Search

Objective To develop an asleep motor mapping paradigm for accurate detection of the corticospinal tract during glioma surgery and compare outcomes with awake patients undergoing glioma resection. Methods A consecutive cohort of adult patients undergoing craniotomy for suspected diffuse glioma with tumor in a perirolandic location who had awake or asleep cortical and subcortical motor mapping with positive areas of motor stimulation were assessed for postoperative extent of resection (EOR), permanent neurological deficit, and proximity of stimulation to diffusion tensor imaging–based corticospinal tract depiction on preoperative magnetic resonance imaging. Outcome data were compared between asleep and awake groups. Results In the asleep group, all 16 patients had improved or no change in motor function at last follow-up (minimum 3 months of follow-up). In the awake group, all 23 patients had improved function or no change at last follow-up. EOR was greater in the asleep group (mean [SD] EOR 88.71% [17.56%]) versus the awake group (mean [SD] EOR 80.62% [24.44%]), although this difference was not statistically significant (P = 0.3802). Linear regression comparing distance from stimulation to corticospinal tract in asleep (n = 14) and awake (n = 4) patients was r = −0.3759, R2 = 0.1413, P = 0.1853, and 95% confidence interval = −0.4453 to 0.09611 and r = 0.7326, R2 = 0.5367, P = 0.2674, and 95% confidence interval = −7.042 to 14.75, respectively. Conclusion In this small patient series, asleep motor mapping using commonly available motor evoked potential hardware appears to be safe and efficacious in regard to EOR and functional outcomes.

The cholinergic neurotransmitter system in the brain is crucial in processing information related to cognitive, behavioral, and motor functions. A cholinergic dysfunction has been correctly described as one of the primary causes of neurodegenerative diseases. Differences in levels of acetylcholine or expression and function of receptors in selected brain areas have been indicated as one of the causes of sexual dimorphism in neurotransmission. However, variability in results among studies based on different mice strains could affect conclusions on this topic. Visual evoked potentials (VEPs) of male and female DBA/2J and C57BL/6J mice, which are two of the most common strains backgrounds in use for developing transgenic mice models of neurological diseases, have been studied. Effects induced by a single low dose of physostigmine have also been performed to evaluate the cholinergic system involvement. VEPs responses to luminous stimuli in C57BL/6J mice have shown a consistently lower latency than in DBA/2J, confirming the previous observation of strain differences in cholinergic function. Interestingly, strains present an opposite-sex difference in VEP latency not apparently related to sensitivity to physostigmine. These findings point at paying extreme attention to the choice of the genetic background of the animal model, especially in those basic and pre-clinical experiments that involve visual functioning.

Theoretical frameworks such as predictive coding suggest that the perception of the body and world – interoception and exteroception – involve intertwined processes of inference, learning, and prediction. In this framework, attention is thought to gate the influence of sensory information on perception. In contrast to exteroception, there is limited evidence for purely attentional effects on interoception. Here, we empirically tested if attentional focus modulates cortical processing of single heartbeats, using a newly-developed experimental paradigm to probe purely attentional differences between exteroceptive and interoceptive conditions in the heartbeat evoked potential (HEP) using EEG recordings. We found that the HEP is significantly higher during interoceptive compared to exteroceptive attention, in a time window of 524–620 ms after the R-peak. Furthermore, this effect predicted self-report measures of autonomic system reactivity. Our study thus provides direct evidence that the HEP is modulated by pure attention and suggests that this effect may provide a clinically relevant readout for assessing interoception., NeuroImage, 186, ISSN:1053-8119, ISSN:1095-9572

Neuropathy may cause fecal incontinence and mixed fecal incontinence/constipation, but its prevalence is unclear, partly due to the lack of comprehensive testing of spino-anorectal innervation.This study aimed to develop and determine the clinical usefulness of a novel test, translumbosacral anorectal magnetic stimulation for fecal incontinence.This observational cohort study was conducted from 2012 to 2018.This study was performed at a tertiary referral center.Patients with fecal incontinence, patients with mixed fecal incontinence/constipation, and healthy controls were included.A translumbosacral anorectal magnetic stimulation test was performed by using an anorectal probe with 4 ring electrodes and magnetic coil, and by stimulating bilateral lumbar and sacral plexuses, uses and recording 8 motor-evoked potentials at anal and rectal sites.The prevalence of lumbar and/or sacral neuropathy was examined. Secondary outcomes were correlation of neuropathy with anorectal sensorimotor function(s) and morphological changes.We evaluated 220 patients: 144 with fecal incontinence, 76 with mixed fecal incontinence/constipation, and 31 healthy controls. All 8 lumbar and sacral motor-evoked potential latencies were significantly prolonged (p0.01) in fecal incontinence and mixed fecal incontinence/constipation groups compared with controls. Neuropathy was patchy and involved 4.0 (3.0) (median (interquartile range)) sites. Lumbar neuropathy was seen in 29% to 65% of the patients in the fecal incontinence group and 22% to 61% of the patients in the mixed fecal incontinence/constipation group, and sacral neuropathy was seen in 24% to 64% and 29% to 61% of these patients. Anal neuropathy was significantly more (p0.001) prevalent than rectal neuropathy in both groups. There was no correlation between motor-evoked potential latencies and anal sphincter pressures, rectal sensation, or anal sphincter defects.No comparative analysis with electromyography was performed.Lumbar or sacral plexus neuropathy was detected in 40% to 75% of patients with fecal incontinence with a 2-fold greater prevalence at the anal region than the rectum. Lumbosacral neuropathy appears to be an independent mechanism in the pathogenesis of fecal incontinence, unassociated with other sensorimotor dysfunctions. Translumbosacral anorectal magnetic stimulation has a high yield and is a safe and clinically useful neurophysiological test. See Video Abstract at http://links.lww.com/DCR/B728.ANTECEDENTES:La neuropatía puede causar incontinencia fecal y una combinación de incontinencia fe-cal/estreñimiento, pero su prevalencia no está clara, en parte debido a la falta de pruebas comple-tas de inervación espino-anorrectal.OBJETIVO:Desarrollar y determinar la utilidad clínica de una nueva prueba, estimulación magnética trans-lumbosacral anorrectal para la incontinencia fecal.DISEÑO:Estudio de cohorte observacional del 2012 al 2018.ENTORNO CLINICO:Centro de referencia terciario.PACIENTES:Pacientes con incontinencia fecal, combinación de incontinencia fecal/estreñimiento y controles sanos.INTERVENCIONES:Se realizó una prueba de estimulación magnética translumbosacral anorrectal utilizando una sonda anorrectal con 4 electrodos anulares y bobina magnética, y estimulando los plexos lumbares y sacros bilaterales y registrando ocho potenciales evocados motores las regiones anal y rectal.PRINCIPALES MEDIDAS DE RESULTADO:Se examinó la prevalencia de neuropatía lumbar y/o sacra. Los resultados secundarios fueron la correlación de la neuropatía con las funciones sensitivomotoras anorrectales y cambios morfológi-cos.RESULTADOS:Evaluamos 220 pacientes, 144 con incontinencia fecal, 76 con combinación de incontinencia fe-cal/estreñimiento y 31 sujetos sanos. Las ocho latencias de los potenciales evocadas motoras lum-bares y sacras se prolongaron significativamente (p0,01) en la incontinencia fecal y el grupo mixto en comparación con los controles. La neuropatía fue irregular y afectaba 4,0 (3,0) (mediana (rango intercuartílico) sitios. Se observó neuropatía lumbar en 29-65% en la incontinencia fecal y 22-61% en el grupo mixto, y neuropatía sacra en 24-64% y 29-61 % de pacientes respectivamen-te. La neuropatía anal fue significativamente más prevalente (p0,001) que la rectal en ambos grupos. No hubo correlación entre las latencias de los potenciales evocadas motoras y las presio-nes del esfínter anal, la sensación rectal o los defectos del esfínter anal.LIMITACIONES:Sin análisis comparativo con electromiografía.CONCLUSIÓNES:Se detectó neuropatía del plexo lumbar o sacro en el 40-75% de los pacientes con incontinencia fecal con una prevalencia dos veces mayor en la región anal que en el recto. La neuropatía lumbo-sacra parece ser un mecanismo independiente en la patogenia de la incontinencia fecal, no asocia-do con otras disfunciones sensitivomotoras. La estimulación magnética translumbosacral anorrec-tal tiene un alto rendimiento, es una prueba neurofisiológica segura y clínicamente útil. Consulte Video Resumen en http://links.lww.com/DCR/B728.

To evaluate and compare efficacy of intraoperative neurophysiological monitoring (IONM) and intraoperative transcranial Doppler (TCD) techniques for identification of hypoperfusion during carotid artery clamp and hyperperfusion after release of occlusion during carotid endarterectomy.This was a retrospective, consecutive case series of 152 patients undergoing carotid endarterectomy between June 2018 and March 2020. Somatosensory evoked potentials, motor evoked potentials, electroencephalogram, and TCD were obtained.Three patient cohorts were observed after clamping the carotid artery: A, in 132 of 152 patients (87%), TCD blood flow velocity decreased by50% and there were no changes in IONM; B, in 5 of 152 (3%) patients, TCD blood flow rate was reduced 50%-100% with no changes in IONM; C, in 15 patients (10%), blood flow velocity was reduced by 50%-100% and all IONM modalities met warning criteria. With increased blood pressure, IONM and blood flow velocities improved to less than warning criteria in 8 of 15 patients. In 6 of the 7 remaining patients, IONM modalities recovered to baseline immediately after clamps were removed from the carotid artery. The 1 patient with persistent motor evoked potential deterioration experienced postoperative proximal muscle weakness, which recovered 48 hours later. In 22 patients, TCD detected hyperperfusion at the moment of clamp release.TCD blood flow velocity is correlated with motor evoked potential and somatosensory evoked potential amplitude changes after clamping. After declamping, TCD can detect hyperperfusion and help regulate blood pressure to prevent hyperperfusion.

Objective Hepatic encephalopathy (HE) is a potentially reversible brain dysfunction caused by liver failure. Altered synaptic plasticity is supposed to play a major role in the pathophysiology of HE. Here, we used paired associative stimulation with an inter-stimulus interval of 25 ms (PAS25), a transcranial magnetic stimulation (TMS) protocol, to test synaptic plasticity of the motor cortex in patients with manifest HE. Methods 23 HE-patients and 23 healthy controls were enrolled in the study. Motor evoked potential (MEP) amplitudes were assessed as measure for cortical excitability. Time courses of MEP amplitude changes after the PAS25 intervention were compared between both groups. Results MEP-amplitudes increased after PAS25 in the control group, indicating PAS25-induced synaptic plasticity in healthy controls, as expected. In contrast, MEP-amplitudes within the HE group did not change and were lower than in the control group, indicating no induction of plasticity. Conclusions Our study revealed reduced synaptic plasticity of the primary motor cortex in HE. Significance Reduced synaptic plasticity in HE provides a link between pathological changes on the molecular level and early clinical symptoms of the disease. This decrease may be caused by disturbances in the glutamatergic neurotransmission due to the known hyperammonemia in HE patients.

EEG has been central to investigations of the time course of various neural functions underpinning visual word recognition. Recently the steady-state visual evoked potential (SSVEP) paradigm has been increasingly adopted for word recognition studies due to its high signal-to-noise ratio. Such studies, however, have been typically framed around a single source in the left ventral occipitotemporal cortex (vOT). Here, we combine SSVEP recorded from 16 adult native English speakers with a data-driven spatial filtering approach—Reliable Components Analysis (RCA)—to elucidate distinct functional sources with overlapping yet separable time courses and topographies that emerge when contrasting words with pseudofont visual controls. The first component topography was maximal over left vOT regions with a shorter latency (approximately 180 ms). A second component was maximal over more dorsal parietal regions with a longer latency (approximately 260 ms). Both components consistently emerged across a range of parameter manipulations including changes in the spatial overlap between successive stimuli, and changes in both base and deviation frequency. We then contrasted word-in-nonword and word-in-pseudoword to test the hierarchical processing mechanisms underlying visual word recognition. Results suggest that these hierarchical contrasts fail to evoke a unitary component that might be reasonably associated with lexical access.

Background High-resolution MR imaging enables the visualization of individual nerves in the internal auditory canal (IAC). Cochlear nerve deficiency (CND) is recognized as one of the major causes of sensory neural hearing loss (SNHL), especially in cases of unilateral hearing loss in childhood. Some patients with CND are thought to have accompanying vestibular nerve deficiency (VND). However, there have been few reports focusing on VND and vestibular function in these children. Aims The aim of this study was to evaluate the frequency of VND and vestibular dysfunction in children with unilateral SNHL caused by CND. Material and methods Thirty-eight children with unilateral SNHL, who were diagnosed with CND by 3 T-MRI, were evaluated for VND and underwent caloric testing and cervical vestibular evoked potential (cVEMP). Results Fourteen of 38 patients (37%) had VND, and eleven (29%) of the patients [ten of the patients (71%) with VND] had at least one vestibular dysfunction. The patients with VND had significantly worse hearing and an IAC of smaller diameter than did patients without VND. Conclusions and significance We should pay attention to VND as well as vestibular dysfunction in hearing loss patients with CND.

Although voluntary muscle contraction modulates spinal reflex excitability of contracted muscles and other muscles located at other segments within a limb (i.e., intra-limb modulation), to what extent corticospinal pathways are involved in intra-limb modulation of spinal reflex circuits remains unknown. The purpose of the present study was to identify differences in the involvement of corticospinal pathways in intra-limb modulation of spinal reflex circuits among lower-limb muscles during voluntary contractions. Ten young males performed isometric plantar-flexion, dorsi-flexion, knee extension, and knee flexion at 10% of each maximal torque. Electromyographic activity was recorded from soleus, tibialis anterior, vastus lateralis, and biceps femoris muscles. Motor evoked potentials and posterior root-muscle reflexes during rest and isometric contractions were elicited from the lower-limb muscles using transcranial magnetic stimulation and transcutaneous spinal cord stimulation, respectively. Motor evoked potential and posterior root-muscle reflex amplitudes of soleus during knee extension were significantly increased compared to rest. The motor evoked potential amplitude of biceps femoris during dorsi-flexion was significantly increased, whereas the posterior root-muscle reflex amplitude of biceps femoris during dorsi-flexion was significantly decreased compared to rest. These results suggest that corticospinal and spinal reflex excitabilities of soleus are facilitated during knee extension, whereas intra-limb modulation of biceps femoris during dorsi-flexion appeared to be inverse between corticospinal and spinal reflex circuits.

Gut microbiota may affect function of the dorsolateral prefrontal cortex (DLPFC). However, there have been a few studies on modification of brain-gut interactions with repetitive transcranial magnetic stimulation (rTMS) to the DLPFC. We hypothesized that stimulation of the right or left DPFC by rTMS modifies the brain-gut interactions in humans. Subjects were 25 healthy males. Viscerosensory evoked potential (VEP) with sham (0 mA) or actual (30 mA) electrical stimulation (ES) of the rectum was taken after sham, low frequency rTMS at 0.1 Hz, and high frequency rTMS at 10 Hz to the right or left DLPFC. Rectal tone was measured with a rectal barostat. Visceral perception and emotion were analyzed using ordinates scale, rectal barostat, and viscerosensory evoked potential. Low frequency rTMS to the right DLPFC significantly reduced the visceral sensation and emotion composite score evoked by ES at 30 mA (p < 0.05). Plasma ACTH was significantly increased by high frequency rTMS to the right or left DLPFC (p < 0.05). Rectal fine contractions were significantly induced by low frequency rTMS to the right or left DLPFC and high frequency rTMS to the right DLPFC (p < 0.05). These results suggest that stimulation of the right or left DPFC by rTMS modifies the brain-gut interactions in humans.

Visual perception is biased by the preceding visual environment. A well-known perceptual bias is the negative bias where a current percept is biased away from the preceding image (adaptor). The preceding adaptor induces augmentation of early visual evoked potential (the P1 enhancement) of the following test image; the adaptor may invoke certain visual processing for the subsequent test image. However, the visual mechanism underlying P1 enhancement remains unclear. The present study assessed what the P1 alteration reflects in relation to the occurrence of the negative bias. In terms of inter-individual differences, we report that the P1 enhancement of the Necker lattice significantly correlated with the reduction of the reverse-bias effect. Further analyses revealed that the P1 enhancement was insusceptible to neural adaptation to the adaptor at the level of perceptual configuration. The present study suggests that prolonged exposure to a visual image induces modulatory visual processing for the subsequent image (reflected in the P1 enhancement), which is relevant to counteraction of the negative bias.

Towards eliminating stimulus artifacts, alternating polarity stimuli have been widely adopted in eliciting the auditory brainstem response. However, considering the difference in the physiologic basis of the positive and negative polarity stimuli on the auditory system, it is unclear whether alternating polarity stimuli would adversely affect the auditory brainstem response characteristics. This research proposes a new polarity method for stimulus artifacts elimination, Sum polarity, that separately utilized the rarefaction and condensation stimuli and then summed the two evoked responses. We compared the waveform morphology and latencies of the auditory brainstem responses evoked by familiar stimuli (including click, tone-burst, and chirp) with different polarity methods in normal-hearing subjects to investigate the new method’s effectiveness. The experimental results showed that alternating polarity of the click and chirp had little effect on the auditory brainstem response. In contrast, alternating polarity affected the waveform morphology and latencies of the auditory brainstem responses to the low-frequency tone-burst, with the effect decreasing as the stimulus frequency increased. These results demonstrated the performance of any polarity method is related to the characteristics of the stimulus signal itself, and no polarity method is optimal for all types of stimuli. Based on the analysis of experimental results, a fixed polarity and alternating polarity were recommended for the click and chirp auditory brainstem responses, respectively. Furthermore, considering the apparent latency differences between the responses to opposite polarity stimuli, the Sum polarity was suggested for the tone-burst auditory brainstem responses. Moreover, this work verified the feasibility of the Sum polarity, which offers another choice for eliminating stimulus artifacts in an evoked potential acquisition.

It is now widely accepted that seizures arise from the coordinated activity of epileptic networks, and as a result, traditional methods of analyzing seizures have been augmented by techniques like single‐pulse electrical stimulation (SPES) that estimate effective connectivity in brain networks. We used SPES and graph analytics in 18 patients undergoing intracranial EEG monitoring to investigate effective connectivity between recording sites within and outside mesial temporal structures. We compared evoked potential amplitude, network density, and centrality measures inside and outside the mesial temporal region (MTR) across three patient groups: focal epileptogenic MTR, multifocal epileptogenic MTR, and non‐epileptogenic MTR. Effective connectivity within the MTR had significantly greater magnitude (evoked potential amplitude) and network density, regardless of epileptogenicity. However, effective connectivity between MTR and surrounding non‐epileptogenic regions was of greater magnitude and density in patients with focal epileptogenic MTR compared to patients with multifocal epileptogenic MTR and those with non‐epileptogenic MTR. Moreover, electrodes within focal epileptogenic MTR had significantly greater outward network centrality compared to electrodes outside non‐epileptogenic regions and to multifocal and non‐epileptogenic MTR. Our results indicate that the MTR is a robustly connected subnetwork that can exert an overall elevated propagative influence over other brain regions when it is epileptogenic. Understanding the underlying effective connectivity and roles of epileptogenic regions within the larger network may provide insights that eventually lead to improved surgical outcomes., Hays et al. utilize evoked potentials from single‐pulse electrical stimulation to map effective networks in mesial temporal epilepsy patients. Graph theoretical analysis of these connections is applied to characterize the role of mesial temporal structures within broader epileptogenic networks, revealing a highly hyperexcitable and influential densely connected subnetwork. This approach provides additional groundwork to better understand epilepsy as a network disorder and identify epileptogenic hubs of connectivity for network targeted treatments.

STUDY DESIGN Prospective multicenter study. OBJECTIVE To examine transcranial motor evoked potential (Tc-MEP) waveforms in intraoperative neurophysiological monitoring (IONM) in surgery for intradural extramedullary (IDEM) tumors, focused on the characteristics for cervical, thoracic and conus lesions. SUMMARY OF BACKGROUND DATA IDEM tumors are normally curable after resection, but neurological deterioration may occur after surgery. IONM using Tc-MEPs during surgery is important for timely detection of possible neurological injury. METHODS The subjects were 233 patients with IDEM tumors treated surgically with Tc-MEP monitoring at 9 centers. The alarm threshold was ≥70% waveform deterioration from baseline. A case with a Tc-MEP alert that normalized and had no new motor deficits postoperatively was defined as a rescue case. A deterioration of manual muscle test (MMT) score ≥1 compared to the preoperative value was defined as postoperative worsening of motor status. RESULTS The 233 patients (92 males, 39%) had a mean age of 58.1 ± 18.1 years, and 185 (79%), 46 (20%) and 2 (1%) had schwannoma, meningioma, and neurofibroma. These lesions had cervical (C1-7), thoracic (Th1-10), and conus (Th11-L2) locations in 82 (35%), 96 (41%) and 55 (24%) cases. There were no significant differences in preoperative motor deficit among the lesion levels. Thoracic lesions had a significantly higher rate of poor baseline waveform derivation (0% cervical, 6% thoracic, 0% conus, p

OBJECTIVE Identification of the motor area during awake craniotomy is crucial for preservation of motor function when resecting gliomas located within or close to the motor area or the pyramidal tract. Nevertheless, sometimes the surgeon cannot identify the motor area during awake craniotomy. However, the factors that influence failure to identify the motor area have not been elucidated. The aim of this study was to assess whether tumor localization was correlated with a negative cortical response in motor mapping during awake craniotomy in patients with gliomas located within or close to the motor area or pyramidal tract. METHODS Between April 2000 and May 2019 at Tokyo Women’s Medical University, awake craniotomy was performed to preserve motor function in 137 patients with supratentorial glioma. Ninety-one of these patients underwent intraoperative cortical motor mapping for a primary glioma located within or close to the motor area or pyramidal tract and were enrolled in the study. MRI was used to evaluate whether or not the tumors were localized to or involved the precentral gyrus. The authors performed motor functional mapping with electrical stimulation during awake craniotomy and evaluated the correlation between identification of the motor area and various clinical characteristics, including localization to the precentral gyrus. RESULTS Thirty-four of the 91 patients had tumors that were localized to the precentral gyrus. The mean extent of resection was 89.4%. Univariate analyses revealed that identification of the motor area correlated significantly with age and localization to the precentral gyrus. Multivariate analyses showed that older age (≥ 45 years), larger tumor volume (> 35.5 cm3), and localization to the precentral gyrus were significantly correlated with failure to identify the motor area (p = 0.0021, 0.0484, and 0.0015, respectively). Localization to the precentral gyrus showed the highest odds ratio (14.135) of all regressors. CONCLUSIONS Identification of the motor area can be difficult when a supratentorial glioma is localized to the precentral gyrus. The authors’ findings are important when performing awake craniotomy for glioma located within or close to the motor area or the pyramidal tract. A combination of transcortical motor evoked potential monitoring and awake craniotomy including subcortical motor mapping may be needed for removal of gliomas showing negative responses in the motor area to preserve the motor-related subcortical fibers.

Objective To explore the value of multi‐mode neuroelectrophysiological monitoring (MIOM) in evaluating spinal cord and nerve root function in the treatment of thoracic tuberculosis via costal transverse process approach. Methods From December 2017 to September 2019, a retrospective study of thoracic tuberculosis patients in our hospital was conducted. This study included 25 patients (14 men and 11 women). The average age of patients at the time of surgery was 63.3 years (range, 20–83 years). All patients (three cases with the destruction of a single vertebral body, 13 cases with the destruction of two vertebral bodies, and nine cases with the destruction of three or more vertebral bodies) underwent costal transverse process approach with debridement and bone grafting and internal fixation combined with intraoperative multimodal neuroelectrophysiological monitoring. During the operation, somatosensory evoked potential (SEP), transcranial electrical stimulation motor evoked potential (TES‐MEP), and spontaneous electromyography (EMG) were used to monitor progress. ESR, visual analogue scale (VAS), Cobb angle, and Oswestry disability index (ODI) were statistically analyzed to evaluate the treatment effects and patient satisfaction. Results All 25 patients were successfully monitored. The follow‐up time ranged from 12 to 21 months, with an average of 15.3 months. SEP waveform abnormalities occurred in five patients during the operation, the incidence rate was 28%. Of these five patients, three patients changed their instruments and postures, and adjusted the flushing water flow in time; one patient received pressure therapy in time; the operation was suspended for 10 min for one patient. There were seven cases with abnormal TES‐MEP waveform, the incidence rate was 28%. Among these seven cases, five cases adjusted the nail path during the operation and adjusted the nail position in time. One case adjusted the inclination angle of the operating table in time; one case completed the contralateral nail stick correction in time; five of them had abnormal TES‐MEP waveforms, and EMG burst potential was also detected, the incidence rate was 20%. After prompt treatment, the abnormal waveforms of all patients returned to normal; no abnormal waveforms, recurrence of tuberculosis, loosening of internal fixation, nerve and spinal cord dysfunction, etc. The VAS score, erythrocyte sedimentation rate (ESR), Cobb angle, and ODI scores of the patients 1 year after operation were significantly improved compared with 1 week after operation (P, This article of mine is a clinical category, and the four pictures each reflect the method of surgery, intraoperative monitoring and imaging data, and the four pictures collectively reflect the entire clinical observation.

Objective Cortico-cortical evoked potential (CCEP) by single-pulse electrical stimulation (SPES) is useful to investigate effective connectivity and cortical excitability. We aimed to clarify the safety of CCEPs. Methods We retrospectively analyzed 29 consecutive patients with intractable partial epilepsy undergoing chronic subdural grid implantation and CCEP recording. Repetitive SPES (1 Hz) was systematically applied to a pair of adjacent electrodes over almost all electrodes. We evaluated the incidences of afterdischarges (ADs) and clinical seizures. Results Out of 1283 electrode pairs, ADs and clinical seizures were observed in 12 and 5 pairs (0.94% and 0.39%, per electrode pair) in 7 and 3 patients (23.3% and 10.0%, per patient), respectively. Of the 18–82 pairs per patient, ADs and clinical seizures were induced in 0–4 and 0–3 pairs, respectively. Stimulating 4 SOZ (seizure onset zone) (2.5%) and 8 non-SOZ pairs (0.75%) resulted in ADs. We observed clinical seizures in stimulating 4 SOZ (2.5%) and 1 non-SOZ pair (0.09%). The incidence of clinical seizures varied significantly between SOZ and non-SOZ stimulations (p = 0.001), while the difference in AD incidence tended towards significance (p = 0.058). Conclusion Although caution should be taken in stimulating SOZ, CCEP is a safe procedure for presurgical evaluation. Significance CCEP is safe under the established protocol.

Objective The current methods used to assess visual function in blind retinitis pigmentosa (RP) patients are mostly subjective. We aimed to identify effective, objective methods. Methods We enrolled patients diagnosed with blindness associated with RP; we finally selected 26 patients (51 eyes) with a visual field radius less than 10 degrees and divided them into the following 4 groups by best-corrected visual acuity (BCVA): group 1, no light perception (NLP, 4 eyes); group 2, light perception (LP, 12 eyes); group 3, hand movement or finger counting (faint form perception, FFP, 22 eyes); and group 4, BCVA from 0.1 to 0.8 (form perception, FP, 13 eyes). All patients underwent optometry, optical coherence tomography (OCT), color fundus photography, fundus autofluorescence (FAF), full field electroretinography (ffERG), pattern electroretinography (PERG), multifocal electroretinography (mf-ERG), pattern visual evoked potential (PVEP), flash visual evoked potential (FVEP), and pupillary light response (PLR) assessments. Five patients in groups 1, 2, and 3 (1, 2, and 2 subjects, respectively) underwent functional magnetic resonance imaging (fMRI) scans and were compared with five healthy subjects. Results The outer plexiform layer was thinner in group 1, and the outer nuclear layer was thinner in groups 1 and 2. The ffERG, PERG, and mf-ERG findings were unrecordable in all four groups. The P2 amplitude of the FVEP was significantly lower in groups 1 and 2, while the P100 amplitude of the PVEP was higher in groups 2, 3 and 4 than in group 1. After white- and blue-light stimuli, the PLR thresholds in the patients without form perception were significantly higher. The threshold of the PLR stimulated by blue and white light was negatively correlated with the amplitudes of P2 and P100. Moreover, the fMRI findings showed that some RP patients have significant visual cortex activation in response to certain types of stimulation. However, statistical analysis was not performed because of the small number of cases. Conclusions OCT, VEP, PLR and fMRI assessments can evaluate residual visual pathway function in blind RP patients. Significance Our study may have clinical significance for the potential prediction of RP patient prognoses and the effects after clinical trials.

Objective To correlate intraoperative changes of the laryngeal adductor reflex (LAR), alone or in combination with corticobulbar motor evoked potential of vocal muscles (vocal-CoMEPs), with postoperative laryngeal function after posterior fossa and brainstem surgery. Methods We monitored 53 patients during cerebellar-pontine angle and brainstem surgeries. Vocal-CoMEPs and LAR were recorded from an endotracheal tube with imbedded electrodes or hook-wires electrodes. A LAR significant change (LAR-SC) defined as ≥ 50% amplitude decrement or loss, was classified as either transient or permanent injury to the vagus or medullary pathways by the end of the surgery. Results All patients with permanent LAR loss (n = 5) or LAR-SC (n = 3), developed postoperative laryngeal dysfunction such as aspiration/pneumonia and permanent swallowing deficits (5.6%). Vocal-CoMEP findings refined postoperative vocal motor dysfunction. All seven patients with transient LAR-SC or loss, reverted by changing the surgical approach, did not present permanent deficits. Conclusions Permanent LAR-SCs or loss correlated with postoperative laryngeal dysfunction and predicted motor and sensory dysfunction of the vagus nerve and reflexive medullary pathways. In contrast, a LAR-SC or loss, averted by a timely surgical adjustment, prevented irreversible damage. Significance Monitoring of the LAR, with vocal-CoMEPs, may enhance safety to resect complex posterior fossa and brainstem lesions.

Aim: The aim of the study was to determine the morphological and functional findings in a patient after methanol poisoning. Examination methods: The patient (male, 38 years old) was suffered methanol poisoning in eight years ago (2012). The following tests and examinations were performed: neurological visual field XR test (Medmont M700), retinal nerve fibre layer (RNFL), ganglion cell complex (GCC) and peripapillary vessel density (all using Avanti RTvue, Optovue), pattern electroretinography (PERG) and pattern visual evoked potential (PVEP) examination according to ISCEV methodology (Roland Consult Instrument) and brain MRI examination (Philips Achieva Dstream 3 T). Results: The biggest changes were found in RNFL and VD. PERG also showed damage to retinal ganglion cell axons. In left eye we determined decrease in oscillations (in comparison with contralateral eye) at N35-P50 and P50-N95. VEPs in both eyes were significantly reduced, almost inconspicuous in the left eye. Extension of latency time of P100 was not identified. Functional MRI showed a bilateral decrease in voxel activity with a greater decrease in the left eye. There were postmalatical changes in the dorsal parts of the putamen on MRI. The width of the optic nerve and chiasm was physiological. Conclusion: Asymmetric damaging of RNFL and cortical centres of the brain were determined. We registered large pathological changes in VD, which are probably responsible for the deepening of optic nerve excavation and further loss of nerve fibers of retinal ganglion cells, which have not yet been described in the literature. Following these results is possible to define direct damage of nerve structures and blood vessels by toxins of methanol metabolism in the acute stage and upcoming reparation processes in following periods.

Precise monitoring of the brain after a stroke is essential for clinical decision making. Due to the non-invasive nature and high temporal resolution of electroencephalography (EEG), it is widely used to evaluate real-time cortical activity. In this study, we investigated the stroke-related EEG biomarkers and developed a predictive model for quantifying the structural brain damage in a focal cerebral ischaemic rat model. We enrolled 31 male Sprague–Dawley rats and randomly assigned them to mild stroke, moderate stroke, severe stroke, and control groups. We induced photothrombotic stroke targeting the right auditory cortex. We then acquired EEG signal responses to sound stimuli (frequency linearly increasing from 8 to 12 kHz with 750 ms duration). Power spectral analysis revealed a significant correlation of the relative powers of alpha, theta, delta, delta/alpha ratio, and (delta + theta)/(alpha + beta) ratio with the stroke lesion volume. The auditory evoked potential analysis revealed a significant association of amplitude and latency with stroke lesion volume. Finally, we developed a multiple regression model combining EEG predictors for quantifying the ischaemic lesion (R2 = 0.938, p value

Rationale: The combination of medical and tissue engineering in neural regeneration studies is a promising field. Collagen, silk fibroin and seed cells are suitable options and have been widely used in the repair of spinal cord injury. In this study, we aimed to determine whether the implantation of a complex fabricated with collagen/silk fibroin (SF) and the human umbilical cord mesenchymal stem cells (hUCMSCs) can promote cerebral cortex repair and motor functional recovery in a canine model of traumatic brain injury (TBI). Methods: A porous scaffold was fabricated with cross-linked collagen and SF. Its physical properties and degeneration rate were measured. The scaffolds were co-cultured with hUCMSCs after which an implantable complex was formed. After complex implantation to a canine model of TBI, the motor evoked potential (MEP) and magnetic resonance imaging (MRI) were used to evaluate the integrity of the cerebral cortex. The neurologic score, motion capture, surface electromyography (sEMG), and vertical ground reaction force (vGRF) were measured in the analysis of motor functions. In vitro analysis of inflammation levels was performed by Elisa while immunohistochemistry was used in track the fate of hUCMSCs. In situ hybridization, transmission electron microscope, and immunofluorescence were used to assess neural and vascular regeneration. Results: Favorable physical properties, suitable degradation rate, and biocompatibility were observed in the collagen/SF scaffolds. The group with complex implantation exhibited the best cerebral cortex integrity and motor functions. The implantation also led to the regeneration of more blood vessels and nerve fibers, less glial fibers, and inflammatory factors. Conclusion: Implantation of this complex enhanced therapy in traumatic brain injury (TBI) through structural repair and functional recovery. These effects exhibit the translational prospects for the clinical application of this complex.

Objective To investigate how functional integrity of ascending sensory pathways measured by visual and somatosensory evoked potentials (VEP & SEP) is associated with abnormal glycemia and brain injury in newborns treated with hypothermia for hypoxic-ischemic encephalopathy (HIE). Methods Fifty-four neonates ≥ 36 weeks gestational age with HIE underwent glucose testing, VEPs, SEPs, and magnetic resonance imaging (MRI) the first week of life. Minimum and maximum glucose values recorded prior to evoked potential (EP) testing were compared with VEP and SEP measures using generalized estimating equations. Relationships between VEP and SEP measures and brain injury on MRI were assessed. Results Maximum glucose is associated with decreased P200 amplitude, and increased odds that N300 peak will be delayed/absent. Minimum glucose is associated with decreased P22 amplitude. Presence of P200 and N300 peaks is associated with decreased odds of brain injury in the visual processing pathway, with delayed/absent N300 peak associated with increased odds of brain injury in posterior white matter. Conclusions Deviations from normoglycemia are associated with abnormal EPs, and abnormal VEPs are associated with brain injury on MRI in cooled neonates with HIE. Significance Glucose is a modifiable risk factor associated with atypical brain function in neonates with HIE despite hypothermia treatment.

Objective To collect preliminary data on the effects of mexiletine on cortical and axonal hyperexcitability in sporadic amyotrophic lateral sclerosis (ALS) in a phase 2 double-blind randomized controlled trial. Methods Twenty ALS subjects were randomized to placebo and mexiletine 300 mg or 600 mg daily for 4 weeks and assessed by transcranial magnetic stimulation and axonal excitability studies. The primary endpoint was change in resting motor threshold (RMT). Results RMT was unchanged with 4 weeks of mexiletine (combined active therapies) as compared to placebo, which showed a significant increase (p=0.039). Reductions of motor evoked potential (MEP) amplitude (p=0.013) and accommodation half-time (p=0.002), secondary outcome measures of cortical and axonal excitability, respectively, were also evident at 4 weeks on mexiletine. Conclusions The relative stabilization of RMT in the treated subjects was unexpected and could be attributed to unaccounted sources of error or chance. However, a possible alternative cause is neuromodulation preventing an increase. The change in MEP amplitude and accommodation half-time supports the reduction of cortical and axonal hyperexcitability with mexiletine. This article is protected by copyright. All rights reserved.

PURPOSE Acute focal demyelination is the characteristic feature of multiple sclerosis, with the majority of damaged axons undergoing limited remyelination and forming chronic lesions. Potential remyelinating agents are currently under development and there is therefore an urgent need for reliable in vivo biomarkers of remyelination. This study aimed to investigate potential changes in multifocal visual evoked potentials' (mfVEPs) latency in a cohort of relapsing-remitting multiple sclerosis (RRMS) patients. The potential sample size required for a remyelination-based clinical trial using different treatment effect sizes and the mfVEP latency as an outcome measure was also estimated. METHODS A total of 50 RRMS consecutive patients with no previous history of optic neuritis in at least one eye and 15 normal controls of similar age and gender composition were prospectively enrolled. Fifteen patients had a history of unilateral ON more than 12 months earlier, whereas 41 patients demonstrated optic radiations lesions on MRI at baseline. Most patients were on disease modifying therapy. A mfVEP was recorded at baseline and 12 months later. RESULTS At baseline, the mfVEP latency in RRMS patients was delayed compared with normal controls in both optic neuritis and nonoptic neuritis eyes. Latency delay was significantly correlated to optic radiation lesion volume (R2 = 0.38, P < 0.001). There was no significant latency change in multiple sclerosis patients' eyes or optic neuritis and nonoptic neuritis eyes over the follow-up period with latency remaining remarkably constant. This was despite the fact that 46 of 50 patients were on disease-modifying therapies, implying current treatments do not affect myelination in chronic RRMS cases. Sample size calculations to evaluate an additional or alternative remyelinating agent, based on a 40% treatment effect, revealed that a relatively small sample size (78 patients) would be required to demonstrate efficacy in future trials of remyelination therapies. CONCLUSIONS Given its known sensitivity for latency changes and the stability found in this RRMS population, the mfVEP represents an ideal biomarker to assess the degree of latency recovery that may be achieved by remyelination in multiple sclerosis.

INTRODUCTION Hyperactivity of the sympathetic nervous system is considered as an important component involved in the pathological mechanisms of premature ejaculation (PE). However, the neural mechanisms of PE with high sympathetic activity are still not well understood. METHODS The activity of the sympathetic innervations in the penis was evaluated by the sympathetic skin response of the penis (PSSR) with an electromyograph and evoked potential equipment. Resting-state functional magnetic resonance imaging (fMRI) data were acquired from 18 PE patients with high sympathetic activity (sPE), 17 PE patients with normal sympathetic activity (nsPE), and 24 healthy controls (HC). We investigated the neural basis of sPE based on the measure of regional homogeneity (ReHo). Moreover, the correlations between brain regions with altered ReHo and PEDT scores and PSSR latencies in the patient group were explored. RESULTS Altered ReHo values among three groups were found in the temporal, cingulated, and parietal cortex in the default mode network (DMN), as well as the temporal cortex in the auditory network (AUD). Compared with HC, Patients with sPE had increased ReHo values of brain regions in DMN, AUD, and decreased ReHo values of brain regions in DMN. In addition, increased ReHo values were found in DMN of patients with nsPE, while decreased ReHo values were found in DMN and the attention network (AN). Moreover, sPE patients had increased ReHo values in AUD and decreased ReHo values in DMN when compared with nsPE patients. Finally, altered ReHo values of brain regions in DMN and AUD were associated with PEDT scores and PSSR latencies in the patient group. CONCLUSION Our results suggested that PE patients had abnormal ReHo values in DMN, AUD, and AN. Patients with sPE were characterized by increased neuronal activity in AUD and decreased activity in DMN. This highlighted the significances of DMN, AUD, and AN in the pathophysiology of PE and also provided potential neuroimaging biomarkers for distinguishing sPE from nsPE and HC.

Our recent report demonstrated that hesperetin (Hst) as a citrus flavonoid, significantly reduces the levels of demyelination in optic chiasm of rats. Previous evidence also indicated that nano-hesperetin (nano-Hst) possesses beneficial impacts in experimental models of Alzheimer's disease and autism. In this study, the effects of nano-Hst on latency of visual signals, demyelination levels, glial activation, and expression of Olig2 and MBP were evaluated in lysolecithin (LPC)-induced demyelination model. Focal demyelination was induced by injection of LPC (1%, 2 μL) into the rat optic chiasm. Animals received oral administration of nano-Hst at dose of 20 mg/kg for 14 or 21 days post LPC injection. Visual evoked potential (VEP) recording showed that nano-Hst reduces the latency of visual signals and ameliorates the extent of demyelination areas and glial activation. Expression levels of the Olig2 and MBP were also significantly increased in nano-Hst treated rats. Overall, our data suggest that nano-Hst reduces the latency of visual signals through its protective effects on myelin sheath, amelioration of glial activation, and enhancement of endogenous remyelination.

Objective The role of motor cortex reorganization in the development and maintenance of phantom limb pain (PLP) is still unclear. This study aims to evaluate neurophysiological and structural motor cortex asymmetry in patients with PLP and its relationship with pain intensity. Methods Cross-sectional analysis of an ongoing randomized-controlled trial. We evaluated the motor cortex asymmetry through two techniques: i) changes in cortical excitability indexed by transcranial magnetic stimulation (motor evoked potential, paired-pulse paradigms and cortical mapping), and ii) voxel-wise grey matter asymmetry analysis by brain magnetic resonance imaging. Results We included 62 unilateral traumatic lower limb amputees with a mean PLP of 5.9 (SD = 1.79). We found, in the affected hemisphere, an anterior shift of the hand area center of gravity (23 mm, 95% CI 6 to 38, p = 0.005) and a disorganized and widespread representation. Regarding voxel-wise grey matter asymmetry analysis, data from 21 participants show a loss of grey matter volume in the motor area of the affected hemisphere. This asymmetry seems negatively associated with time since amputation. For TMS data, only the ICF ratio is negatively correlated with PLP intensity (r = −0.25, p = 0.04). Conclusion There is an asymmetrical reorganization of the motor cortex in patients with PLP, characterized by a disorganized, widespread, and shifted hand cortical representation and a loss in grey matter volume in the affected hemisphere. This reorganization seems to reduce across time since amputation. However, it is not associated with pain intensity. Significance These findings are significant to understand the role of the motor cortex reorganization in patients with PLP, showing that the pain intensity may be related with other neurophysiological factors, not just cortical reorganization.

Objective Sub-motor threshold 5 Hz repetitive paired associative stimulation (5 Hz-rPAS25ms) produces a long-lasting increase in corticospinal excitability. Assuming a spike-timing dependent plasticity-like (STDP-like) mechanism, we hypothesized that 5 Hz-rPAS at a shorter inter-stimulus interval (ISI) of 15 ms (5 Hz-rPAS15ms) would exert a lasting inhibitory effect on corticospinal excitability. Methods 20 healthy volunteers received two minutes of 5 Hz-rPAS15ms. Transcranial magnetic stimulation (TMS) was applied over the motor hotspot of the right abductor pollicis brevis muscle at 90% active motor threshold. Sub-motor threshold peripheral electrical stimulation was given to the left median nerve 15 ms before each TMS pulse. We assessed changes in mean amplitude of the unconditioned motor evoked potential (MEP), short-latency intracortical inhibition (SICI), intracortical facilitation (ICF), short-latency afferent inhibition (SAI), long-latency afferent inhibition (LAI), and cortical silent period (CSP) before and for 60 minutes after 5-Hz rPAS15ms. Results Subthreshold 5-Hz rPAS15ms produced a 20–40% decrease in mean MEP amplitude along with an attenuation in SAI, lasting at least 60 minutes. A follow-up experiment revealed that MEP facilitation was spatially restricted to the target muscle. Conclusions Subthreshold 5-Hz rPAS15ms effectively suppresses corticospinal excitability. Together with the facilitatory effects of subthreshold 5-Hz rPAS25ms (Quartarone et al., J Physiol 2006;575:657–670), the results show that sub-motor threshold 5-Hz rPAS induces STDP-like bidirectional plasticity in the motor cortex. Significance The results of the present study provide a new short-time paradigm of long term depression (LTD) induction in human sensory-motor cortex.

Significance Measuring pupil diameter may provide an additional objective method to detect and monitor glaucoma. Purpose The purposes of this study were to evaluate whether pupillometry can be used in the assessment of glaucomatous damage and to determine whether pupillometer can be used in glaucoma screening. Methods In this retrospective study, patients with early stages of glaucomatous optic neuropathy were tested using visual evoked potential (VEP), standard automated perimetry, and pupillometer. The VEP record was made using two consecutive check sizes (1° and 15') at 1-Hz frequency. Patients with a mean deviation of -6 dB were included in the study. Pupil size measurements were performed under photopic conditions at 60-, 100-, and 130-cd/m luminance levels with the OPD Scan (Nidek, Gamagori, Japan) device. Results In all, 24 eyes of 24 patients (14 women and 10 men) with newly diagnosed open-angle glaucoma were included, and 30 eyes of 30 healthy subjects (15 women, 15 men) were used as controls. There was no significant difference between sexes in photopic pupil diameters in either group. Comparing the pupil diameters in different luminance levels, the diameters were significantly larger in the patient group. When age-corrected values in the glaucoma group were compared with an age-matched control group, the differences in P100 latency and amplitudes were statistically significant. There were significant correlations between photopic pupil diameters and timing of VEP waveforms. Conclusions There is a relationship between pupil diameters and VEP results in eyes with early glaucoma.

The purpose of this study was to measure the auditory evoked potentials for speech and non-speech sounds with similar spectral distributions.We developed two types of sounds, comprising naturally spoken vowels (natural speech sounds) and complex synthesized sounds (synthesized sounds). Natural speech sounds consisted of 5 Japanese vowels. Synthesized sounds consisted of a fundamental frequency and its second to fifteenth harmonics equivalent to those of natural speech sounds. The synthesized sound was filtered to have a similar spectral distribution to that of each natural speech sound. These sounds were low-pass filtered at 2000 Hz. The auditory evoked potential elicited by the natural speech sound /o/ and synthesized counterpart for /o/ were measured in 10 right-handed healthy adults with normal hearing.The natural speech sounds were significantly highly recognized as speech compared to the synthesized sounds (74.4% v.s. 13.8%, p 0.01). The natural speech and synthesized sounds for the vowel /o/ contrasted strongly for speech perception (96.9% vs. 9.4%, p0.01). However, the vowel /i/ and its counterpart were barely recognized as speech (4.7 v.s. 3.1%, p = 1.00). The N1 peak amplitudes and latencies evoked by the natural speech sound /o/ were not different from those evoked by the synthesized sound (p = 0.58 and p = 0.28, respectively). The P2 amplitudes evoked by the natural speech sound /o/ were not different from those evoked by the synthesized sound (p = 0.51). The P2 latencies evoked by the natural speech sound /o/ were significantly shorter than those evoked by the synthesized sound (p0.01). This modulation was not observed in a control study using the vowel /i/ and its counterpart (p = 0.29).The early P2 observed may reflect central auditory processing of the 'speechness' of complex sounds.

Objective The relevance of motor evoked potential (MEP) recovery during mechanical endovascular thrombectomy (MT) in patients with ischemic stroke is unclear. We correlated MEP recovery during MT to symptom improvement and to ischemia in eloquent motor areas on magnetic resonance imaging (MRI) and compared the predictive value of MEPs to visual angiographic reperfusion status, classified by modified Thrombolysis in Cerebral Infarction grading (mTICI). Methods Patients with hemisyndrome and large-vessel occlusion undergoing MT were included (n35, 49% females; 73.9 ± 14.5 years; n31 anterior circulation). MEPs were elicited transcranially and recorded at the abductor pollicis brevis muscle bilaterally throughout the procedure. An MRI was acquired within 7 days after MT. Results The median door-to-needle time was 3.5 hours. Median National Institutes of Health Stroke Scale at presentation was 16 (7 – 37). Median Modified Rankin Scale score was 4 at day 7 and 3 months. After MT, MEP-recovery occurred in 21 cases after a median time span of 4.5 min [range 2 – 11 min]. Symptom improvement at day 7 (3 months) was noted in 22 (21) cases. Absence of ischemia on postinterventional MRI was noted in 21 cases, 19 of whom showed MEP-recovery. Stratified for symptom improvement at day 7, sensitivity (specificity) of MEP-recovery was 86% (85%) and of mTICI ≥ 2b was 95% (23%). Stratified for absence of ischemia on postinterventional MRI, sensitivity (specificity) of MEP-recovery was 90% (86%) and of mTICI ≥ 2b was of 95% (21%). Conclusions MEP recovery occurs early after successful endovascular mechanical revascularization and is superior to mTICI grading in predicting postoperative neurological outcome and postoperative motor-pathway ischemia. Significance This is a new, significant and clinically important study since it emphasizes the additional value of MEP monitoring in a field, which has been traditionally unaffiliated with neurophysiological monitoring.

Short-interval intracortical inhibition (SICI) is often assessed to investigate inhibitory responses in the primary motor cortex representation of the quadriceps. However, determining appropriate paired-pulse transcranial magnetic stimulation (TMS) parameters to optimise SICI measurement can be impractical and time-consuming. This study investigated the intensity required to elicit maximal and 50% of maximum inhibition, and the test-retest reliability of a time-efficient approach for SICI measurement in quadriceps. Nine men and six women (26.6 ± 4.4 years) underwent single and paired-pulse (3-ms interval) TMS during 10% maximal voluntary isometric contraction on two days. Responses were recorded from vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM). Test stimulus intensity was 140% of active motor threshold (AMT), and conditioning stimulus intensities (CSIs) ranged from 55% to 90% (eight intensities) of AMT (five test and five paired responses for each intensity). With CSI of 55% AMT, SICI was minimal (conditioned:test motor evoked potential [MEP]; 1.00, 0.96 and 0.95 for VL, RF and VM, respectively

Objectives: The objectives of the present study were to analyze the possibility of using pattern VEPs (VEP of pattern type) in glaucoma patients and their role in the follow-up and coordination/ management of anti-glaucoma treatment. Patients and Methods: This is a prospective study on 54 eyes of 30 consecutive glaucoma patients, whose compliance capacity did not allow automatic perimetry and OCT scan to be carried out. The patients were divided into two groups: group A – the study group and group B – the control group. All patients underwent FO exam and pachymetry, plus VEP exam for group A patients. Patients were analyzed at the initial visit and at 1 month, 3, 6, 12 months. Statistical analysis was made using t-test, ANOVA, Fisher test and Pearson correlation coefficient. Results: These participants presented a positive correlation between C/ D ratio and the latency of the P100 wave at 1 degree and a negative correlation between C/ D ratio and the amplitude of the P100 wave both at 1 degree (60 arc minutes) and at 0.25 degrees (15 arc minutes). During the study, the values of the latent P100 changed statistically at 6 months and at 1 year. Using all the data, the authors of the study considered it necessary to modify the treatment for 2 patients out of 13 in group B and for 9 patients out of 16 in group A (p = 0,02892). Conclusions: VEP supplies additional/ further data that significantly help guiding the treatment and monitoring the progression, therefore, it should be part of the routine examination for these patients. Further studies are necessary to deepen our understanding of the visual evoked potentials utility.

Background This study focused on developing an upper limb rehabilitation program. In this regard, a steady state visual evoked potential (SSVEP) triggered brain computer interface (BCI)-functional electrical stimulation (FES) based action observation game featuring a flickering action video was designed. Objective In particular, the synergetic effect of the game was investigated by combining the action observation paradigm with BCI based FES. Methods The BCI-FES system was contrasted under two conditions: with flickering action video and flickering noise video. In this regard, 11 right-handed subjects aged between 22-27 years were recruited. The differences in brain activation in response to the two conditions were examined. Results The results indicate that T3 and P3 channels exhibited greater Mu suppression in 8-13 Hz for the action video than the noise video. Furthermore, T4, C4, and P4 channels indicated augmented high beta (21-30 Hz) for the action in contrast to the noise video. Finally, T4 indicated suppressed low beta (14-20 Hz) for the action video in contrast to the noise video. Conclusion The flickering action video based BCI-FES system induced a more synergetic effect on cortical activation than the flickering noise based system.

ObjectivePreterm infants are exposed earlier than their term counterparts to unattenuated sounds from the external environment during the sensitive period of the organization of the auditory cortical circuitry. In the current study, we investigate the effect of preterm birth on the course of development of auditory cortical areas by evaluating how gestational age (GA) correlates with the latency of the P1 component of the cortical auditory evoked potential (CAEP) of two experimental groups measured at 1 or 3 months of age.ResultsOur sample consisted of 23 infants delivered at GA ranging from 31.28 to 41.42 weeks and separated into two groups evaluated transversally at 1 or 3 months of corrected age (CA). In the group evaluated at 1-month CA, the latency of the component P1 was similar in both terms and infants classified as late-preterm (GA > 32 weeks). However, in the group evaluated at 3 months CA, P1 latency was significantly smaller in preterms. These preliminary results suggest an acceleration of the development of auditory cortical pathways in preterms, probably due to their early exposure to socially relevant auditory stimuli from the external environment.

Objective To propose a method for intraoperative mapping and monitoring of the medial frontal motor areas (MFMA). Methods We estimated the location of the MFMA using the corticocortical evoked potential (CCEP) provoked by electric stimuli to the primary motor area (M1) of the upper limb. We localized or defined the MFMA by recording the motor evoked potentials (MEPs) provoked by electric stimuli to the medial frontal cortex around the estimated area. We monitored the patients' motor function during awake craniotomy and sequentially recorded the MEPs of the upper and/or lower limbs. This method was applied to 8 patients. Results Four patients who had part of the areas identified as the MFMA removed showed transient hemiparesis postoperatively (supplementary motor area [SMA] syndrome). The MEP from the M1 was preserved in the 4 patients. The resection of the identified MFMA might have caused their SMA syndrome. The CCEP showed a strong connection between the M1 and the SMA of the upper limb. Our method did not provoke any seizures. Conclusions This is a safe and sensitive method for intraoperative mapping and monitoring of the MFMA by combining electrophysiologic monitoring and awake craniotomy. It is clinically useful for mapping the MFMA and can prevent permanent motor deficits.

OBJECTIVE: Deep brain stimulation (DBS) is an increasingly applied treatment for various neuropsychiatric disorders including drug-resistant epilepsy, and it may be optimized by rationalizing the stimulation protocol based on increased knowledge of its mechanism of action. We evaluated the effects of minutes to hours of hippocampal DBS on hippocampal evoked potentials (EPs) and local field potentials (LFPs) in freely moving male rats to further investigate some of the previously proposed mechanisms of action.METHODS: Hippocampal high-frequency (130 Hz) DBS was administered for 0, 1, or 6 min every 10 min for 160 min. Stimulation parameter settings were similar to those that had previously been shown to reduce seizures in epileptic rats. EPs and LFPs were recorded in the stimulation-free intervals. We investigated both the immediate temporary effects of 1 or 6 min of DBS and the effects of 160 min of intermittent DBS. Input specificity was investigated by using two different stimulation electrodes.RESULTS: Relatively low DBS intensities corresponding to only 1.8% of the intensity evoking a maximum EP were required to prevent unintended seizure occurrence in healthy rats. Both 1 and 6 min of DBS caused input-specific short-lasting (P = .005). We observed longer-lasting, input-specific EP reductions during the 160 min intermittent DBS, with statistically significant reductions (3%-4%) of the fEPSP slope (P = .009-.018). The LFP spectrogram remained unaltered.SIGNIFICANCE: Deep brain stimulation induced both acute temporary effects compatible with axonal block and/or synaptic depression, and longer-lasting potentially cumulative EP reductions, suggesting the involvement of homeostatic plasticity or long-term depression. This dual time course may parallel the different temporal patterns of improvement observed in clinical trials. The longer-lasting reductions provide a potential neurophysiological basis for the use of intermittent DBS-as typically used in epilepsy patients-as an alternative to continuous DBS.

Background Surgery is usually the treatment of choice for patients with cervical compressive myelopathy (CCM). Motor evoked potential (MEP) has proved to be helpful tool in evaluating intraoperative cervical spinal cord function change of those patients. This study aims to describe and evaluate different MEP baseline phenotypes for predicting MEP changes during CCM surgery. Methods A total of 105 consecutive CCM patients underwent posterior cervical spine decompression were prospectively collected between December 2012 and November 2016. All intraoperative MEP baselines recorded before spinal cord decompression were classified into 5 types (I to V) that were carefully designed according to the different MEP parameters. The postoperative neurologic status of each patient was assessed immediately after surgery. Results The mean intraoperative MEP changes range were 10.2% ± 5.8, 14.7% ± 9.2, 54.8% ± 31.9, 74.1% ± 24.3, and 110% ± 40 in Type I, II, III, IV, and V, respectively. There was a significant correlation of the intraoperative MEP change rate with different MEP baseline phenotypes (r = 0.84, P Conclusions The MEP baselines categories for predicting intraoperative cervical cord function change is proposed through this work. The more serious the MEP baseline abnormality, the higher the probability of intraoperative MEP changes, which is beneficial to early warning for the cervical cord injury.

Background Transcranial magnetic stimulation (TMS) is a rapidly expanding technology utilized in research and neuropsychiatric treatments. Yet, conventional TMS configurations affect primarily neurons that are aligned parallel to the induced electric field by a fixed coil, making the activation orientation-specific. A novel method termed rotational field TMS (rfTMS), where two orthogonal coils are operated with a 90° phase shift, produces rotation of the electric field vector over almost a complete cycle, and may stimulate larger portion of the neuronal population within a given brain area. Objective To compare the physiological effects of rfTMS and conventional unidirectional TMS (udTMS) in the motor cortex. Methods Hand and leg resting motor thresholds (rMT), and motor evoked potential (MEP) amplitudes and latencies (at 120% of rMT), were measured using a dual-coil array based on the H7-coil, in 8 healthy volunteers following stimulation at different orientations of either udTMS or rfTMS. Results For both target areas rfTMS produced significantly lower rMTs and much higher MEPs than those induced by udTMS, for comparable induced electric field amplitude. Both hand and leg rMTs were orientation-dependent. Conclusions rfTMS induces stronger physiologic effects in targeted brain regions at significantly lower intensities. Importantly, given the activation of a much larger population of neurons within a certain brain area, repeated application of rfTMS may induce different neuroplastic effects in neural networks, opening novel research and clinical opportunities.

To evaluate the effectiveness of Visual Evoked Potential (VEP) biofeedback rehabilitation in selected low vision patients with advanced age-related macular degeneration (AMD).Retrospective observational cohort study.Patients affected by advanced AMD, central macular atrophy with unstable fixation and best corrected visual acuity (BCVA) between 20/100 and 20/320 were considered. Selected patients underwent fundus photography and microperimetry with fixation analysis for the selected eye (highest BCVA). Ten consecutive training sessions of 10 min each were performed twice a week in the selected eye with Retimax Vision Trainer (CSO, Florence). BCVA, reading acuity and reading speed, contrast sensitivity, fixation, retinal sensitivity and quality of life questionnaire (VFQ-25) were evaluated at baseline and 7 days following the final session.Significant improvements in terms of BCVA [Preliminary results support VEP biofeedback rehabilitation improvements for visual function and quality of life in advanced AMD patients with low vision.

In recent years, electroencephalography and magnetoencephalography (MEG) have both been used to investigate the response in human auditory cortex to musical sounds that are perceived as consonant or dissonant. These studies have typically focused on the transient components of the physiological activity at sound onset, specifically, the N1 wave of the auditory evoked potential and the auditory evoked field, respectively. Unfortunately, the morphology of the N1 wave is confounded by the prominent neural response to energy onset at stimulus onset. It is also the case that the perception of pitch is not limited to sound onset; the perception lasts as long as the note producing it. This suggests that consonance studies should also consider the sustained activity that appears after the transient components die away. The current MEG study shows how energy-balanced sounds can focus the response waves on the consonance-dissonance distinction rather than energy changes and how source modeling techniques can be used to measure the sustained field associated with extended consonant and dissonant sounds. The study shows that musical dyads evoke distinct transient and sustained neuromagnetic responses in auditory cortex. The form of the response depends on both whether the dyads are consonant or dissonant and whether the listeners are musical or nonmusical. The results also show that auditory cortex requires more time for the early transient processing of dissonant dyads than it does for consonant dyads and that the continuous representation of temporal regularity in auditory cortex might be modulated by processes beyond auditory cortex. NEW & NOTEWORTHY We report a magnetoencephalography (MEG) study on transient and sustained cortical consonance processing. Stimuli were long-duration, energy-balanced, musical dyads that were either consonant or dissonant. Spatiotemporal source analysis revealed specific transient and sustained neuromagnetic activity in response to the dyads; in particular, the morphology of the responses was shaped by the dyad’s consonance and the listener’s musicality. Our results also suggest that the sustained representation of stimulus regularity might be modulated by processes beyond auditory cortex.

BACKGROUND AND PURPOSE Even a single bout of aerobic exercise (AE) enhances corticospinal excitability (CSE), a biomarker of neuroplasticity. Because neurodegeneration limits capacity for neuroplasticity, it is not clear whether AE would induce CSE changes in people with progressive multiple sclerosis (MS). METHODS People with progressive MS (n = 10) requiring ambulatory assistive devices completed a graded maximal exercise test. Dual-energy x-ray absorptiometry was used to quantify body fat and lean mass. Before and following one 40-minute AE session using body weight-supported (

Objective A central concern in aging is the preservation of cognitive skills. Tools to detect cognitive decline are sparse. The aim of this study was to ascertain whether cognitive decline is accompanied by alterations in the temporal dynamics of steady-state visual evoked potentials (SSVEPs). Methods We included 162 men from the Danish Metropolit birth cohort. Their cognitive trajectory was based on their intelligence test score at youth (age ~18), middle age (age ~56), and late middle age (age ~62). Subjects underwent cognitive tests and steady-state visual stimulation. Temporal dynamics of SSVEPs were assessed in terms of amplitude and phase coherence. Results The latency and magnitude of the amplitude modulation of the 36-Hz response correlated negatively with subjects’ cognition indices. Furthermore, negative cognition index was associated with loss of SSVEPs at 36 Hz, and both 8 Hz and 36 Hz in severe cases. Conclusion Latency and magnitude of gamma frequency SSVEPs increase with cognitive decline. This suggests that the facilitation of SSVEPs first becomes problematic at gamma frequencies, then at alpha frequencies. Significance Our data suggests that the temporal dynamics of SSVEPs can be used as an indicator of cognitive impairment. Furthermore, evoked gamma oscillations are especially vulnerable in cognitive decline.

PURPOSE To investigate possible sex-related differences in group III/IV muscle afferent feedback with isometric fatigue, we aimed to assess the effect of a sustained submaximal elbow extensor contraction on motoneuronal excitability (cervicomedullary motor evoked potential [CMEP]) and voluntary activation (VA). METHODS Twenty-four participants (12 females) performed a 15-min contraction at the level of EMG activity recorded at 15% of maximal torque. Each minute, CMEP were elicited by cervicomedullary stimulation with and without conditioning transcranial magnetic stimulation (TMS) delivered 100 ms earlier. Unconditioned and conditioned motor evoked potentials (MEP) in response to TMS were also recorded to assess motor cortical excitability. CMEP and MEP were normalized for changes in downstream excitability and expressed as percentage of their prefatigue (control) values. Postfatigue, VA was calculated from superimposed and resting tetani evoked by stimulation over triceps brachii. RESULTS Males were twice as strong as females, but the sexes did not differ for any variable during the fatigue protocol. On a 0-10 scale, RPE increased from ~2.5 to 9. The unconditioned CMEP did not change, whereas the conditioned CMEP was reduced by ~50%. By contrast, the unconditioned and conditioned MEP increased to ~200% and ~320% of the control values, respectively. At task termination, maximal torque was reduced ~40%, and VA was ~80%, down from a prefatigue value of ~96%. CONCLUSIONS Results support the scant published data on the elbow extensors and indicate no sex-related differences for isometric fatigue of this muscle group. The motoneuronal and VA data suggest that metabolite buildup and group III/IV muscle afferent activity were similar for females and males.

Purpose Anesthetic fade refers to the time-dependent decrease in the amplitude of the intraoperative motor-evoked potential. It is thought to be caused by the accumulation of propofol. The authors examined whether normalization by the compound muscle action potential (CMAP) after peripheral nerve stimulation could compensate for anesthetic fade. Methods In 1,842 muscles in 578 surgeries, which did not exhibit a motor-neurologic change after the operation, the motor-evoked potential amplitude was normalized by the CMAP amplitude after peripheral nerve stimulation, and the CMAP amplitude and operation times were analyzed. Results The amplitudes of both motor-evoked potential and CMAP increased over time after peripheral nerve stimulation because of the disappearance of muscle-relaxant action. Especially, after peripheral nerve stimulation, CMAP significantly increased from the beginning to the end of the operation. Anesthetic fade in transcranial motor-evoked potential monitoring seemed to occur at more than 235 minutes of surgery based on the results of a receiver operating characteristic analysis of the operation time and relative amplitudes. Although the mean amplitude without CMAP normalization at more than 235 minutes was significantly lower than that at less than 235 minutes, the mean amplitude with normalization by CMAP after peripheral nerve stimulation at more than 235 minutes was not significantly different from that at less than 235 minutes. Conclusions Compound muscle action potential after peripheral nerve stimulation normalization was able to avoid the effect of anesthetic fade. Anesthetic fade was seemed to be caused by a decrease in synaptic transmission at the neuromuscular junction because of propofol accumulation by this result.

Purpose To report toxic posterior segment syndrome after dropless cataract surgery using locally compounded triamcinolone-moxifloxacin. Methods A retrospective case review of 7 patients presenting with a decrease in visual acuity after dropless cataract surgery. Results All patients experienced significant reductions in best-corrected visual acuity of the postoperative eye ranging from 20/40 to count finger at 4 feet (average best-corrected visual acuity 20/220) immediately after surgery. The presenting symptoms included flashes, floaters, photophobia, glare, halos, visual distortions, and problems assessing colors. In three cases, foveal retinal pigment epithelium changes were noted on dilated fundus exam (DFE). Ellipsoid zone loss was noted on ocular coherence tomography in five of the seven affected eyes. Electrophysiology testing in five of the seven affected eyes demonstrated large decreases in full-field electroretinogram amplitude, oscillatory potentials, multifocal electroretinogram, and visual evoked potential, along with a negative electroretinogram. One patient was treated with a dexamethasone implant, but no improvement in visual acuity was noted. Conclusion This is the first case series of toxic posterior segment syndrome occurring secondary to intracameral compounded triamcinolone-moxifloxacin in dropless cataract surgery. The FDA has attributed the toxicity to abnormally high levels of the binding agent poloxamer 407 in the compounded medication. Clinicians should be aware of this phenomenon and exhibit caution when using compounded medications.

Blood flow occlusion (BFO) has been used to study the influence of group III/IV muscle afferents after fatiguing exercise, but it is unknown how BFO-induced activity of these afferents affects motor cortical and motoneuronal excitability during low-intensity exercise. Therefore, the purpose of this study was to assess the acute effect of BFO on peripheral [maximal M wave (Mmax)], spinal [cervicomedullary motor evoked potential (CMEP) normalized to Mmax], and motor cortical [motor evoked potential (MEP) normalized to CMEP] excitability. Nine healthy men completed a sustained isometric contraction of the elbow flexors at 20% of maximal force under three conditions: 1) contractile failure with BFO, 2) a time-matched trial without restriction [free flow (FFiso)], and 3) contractile failure with free flow (FFfail). Time to failure for BFO (and FFiso) were ~80% shorter than that for FFfail ( P < 0.05). For FFfail and FFiso, Mmax area decreased ~17% and ~7%, respectively ( P < 0.05), with no change during BFO. CMEP/Mmax area increased ~226% and ~80% during BFO and FFfail, respectively ( P < 0.05), with no change during FFiso ( P > 0.05). The increase in normalized CMEP area was greater for BFO and FFfail compared with FFiso and for BFO compared with FFfail. MEP/CMEP area was not different among the protocols ( P > 0.05) and increased ~64% with time ( P < 0.05). It is likely that group III/IV muscle afferent feedback to the spinal cord modulates the large increase in motoneuronal excitability for the BFO compared with FFfail and FFiso protocols. NEW & NOTEWORTHY We have observed how blood flow occlusion modulates motor cortical, spinal, and peripheral excitability during and immediately after a sustained low-intensity isometric elbow flexion contraction to failure. We conclude that blood flow occlusion causes a greater and more rapid increase in motoneuronal excitability.

Background: Spinal cord dysfunction/compression and ataxia are common in horses. Presumptive diagnosis is most commonly based on neurological examination and cervical radiography, but the interest into the diagnostic value of transcranial magnetic stimulation (TMS) with recording of magnetic motor evoked potentials has increased. The problem for the evaluation of diagnostic tests for spinal cord dysfunction is the absence of a gold standard in the living animal. Objectives: To compare diagnostic accuracy of TMS, cervical radiography, and neurological examination. Animals: One hundred seventy-four horses admitted at the clinic for neurological examination. Methods: Retrospective comparison of neurological examination, cervical radiography, and different TMS criteria, using Bayesian latent class modeling to account for the absence of a gold standard. Results: The Bayesian estimate of the prevalence (95% CI) of spinal cord dysfunction was 58.1 (48.3%-68.3%). Sensitivity and specificity of neurological examination were 97.6 (91.4%-99.9%) and 74.7 (61.0%-96.3%), for radiography they were 43.0 (32.3%-54.6%) and 77.3 (67.1%-86.1%), respectively. Transcranial magnetic stimulation reached a sensitivity and specificity of 87.5 (68.2%-99.2%) and 97.4 (90.4%-99.9%). For TMS, the highest accuracy was obtained using the minimum latency time for the pelvic limbs (Youden's index = 0.85). In all evaluated models, cervical radiography performed poorest. Clinical Relevance: Transcranial magnetic stimulation-magnetic motor evoked potential (TMS-MMEP) was the best test to diagnose spinal cord disease, the neurological examination was the second best, but the accuracy of cervical radiography was low. Selecting animals based on neurological examination (highest sensitivity) and confirming disease by TMS-MMEP (highest specificity) would currently be the optimal diagnostic strategy.