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Recent evidence indicates that transcranial ultrasound stimulation (TUS) modulates sensorimotor cortex excitability. However, no study has assessed possible TUS effects on the excitability of deeper brain areas, such as the brainstem. In this study, we investigated whether TUS delivered on the substantia nigra, superior colliculus, and nucleus raphe magnus modulates the excitability of trigeminal blink reflex, a reliable neurophysiological technique to assess brainstem functions in humans. The recovery cycle of the trigeminal blink reflex (interstimulus intervals of 250 and 500 ms) was tested before (T0), and 3 (T1) and 30 min (T2) after TUS. The effects of substantia nigra-TUS, superior colliculus-TUS, nucleus raphe magnus-TUS and sham-TUS were assessed in separate and randomized sessions. In the superior colliculus-TUS session, the conditioned R2 area increased at T1 compared with T0, while T2 and T0 values did not differ. Results were independent of the interstimulus intervals tested and were not related to trigeminal blink reflex baseline (T0) excitability. Conversely, the conditioned R2 area was comparable at T0, T1, and T2 in the nucleus raphe magnus-TUS and substantia nigra-TUS sessions. Our findings demonstrate that the excitability of brainstem circuits, as evaluated by testing the recovery cycle of the trigeminal blink reflex, can be increased by TUS. This result may reflect the modulation of inhibitory interneurons within the superior colliculus.

The R2 component of blink reflex recovery cycle (R2BRrc) is a simple neurophysiological tool to detect the brainstem hyperexcitability commonly occurring in several neurological diseases such as Parkinson’s disease and atypical parkinsonisms. In our study, we investigated for the first time the usefulness of R2BRrc to assess brainstem excitability in patients with idiopathic Normal Pressure Hydrocephalus (iNPH) in comparison with healthy subjects. Eighteen iNPH patients and 25 age-matched control subjects were enrolled. R2BRrc was bilaterally evaluated at interstimulus intervals (ISIs) of 100, 150, 200, 300, 400, 500 and 750 ms in all participants. We investigated the diagnostic performance of R2BRrc in differentiating iNPH patients from control subjects using ROC analysis. Midbrain area and Magnetic Resonance Hydrocephalic Index (MRHI), an MRI biomarker for the diagnosis of iNPH, were measured on T1-weighted MR images, and correlations between R2BRrc values and MRI measurements were investigated. Fourteen (78%) of 18 iNPH patients showed an enhanced R2BRrc at ISIs 100–150–200 ms, while no control subjects had abnormal R2BRrc. The mean amplitude of bilateral R2BRrc at the shortest ISIs (100–150–200 ms) showed high accuracy in differentiating iNPH patients from controls (AUC = 0.89). R2BRrc values significantly correlated with midbrain area and MRHI values. This study represents the first evidence of brainstem hyperexcitability in iNPH patients. Given its low cost and wide availability, R2BRrc could be a useful tool for selecting elderly subjects with mild gait and urinary dysfunction who should undergo an extensive diagnostic workup for the diagnosis of NPH.

Our aim was to investigate the extent and pattern of involved pathways using brainstem and spinal reflexes by comparing primary progressive freezing of gait (PPFOG) progressive supranuclear palsy (PSP) with FOG. Seven patients with PPFOG and age and sex matched seven PSP patients and 16 healthy subjects were included in the study. All subjects underwent blink reflex (BR), trigemino-cervical reflex (TCR), auditory startle reflex (ASR) and long latency flexor reflex (LLFR) investigations under the same conditions. All three groups had normal BR latencies. ASR probability was lowest in the PSP group and was highest in PPFOG (p=0.005). The presence rate of TCR was lowest in PSP and it was highest in PPFOG (p=0.007 for SC and p=0.023 for SCM). The presence rate and amplitude of LLFR (R II) were decreased in the PSP group (p=0.010 and p=0.031, respectively) whereas it was in a continuous pattern in some of PPFOG patients. ASR, TCR and LLFR were all inhibited in PSP and we suggest that suppression of all three reflexes is probably related to degeneration of brainstem reticular formation and basal ganglia connections. However, interestingly, in PPFOG, excitabilities of ASR and TCR circuits are increased suggesting loss of pathways mediating suprasegmental control.

Botulinum toxin (BTX) is the treatment of choice for blepharospasm. To investigate if the locally injected BTX influences the central nervous system and in particular the brain stem, amplitude and latency of compound muscle action potential (CMAP) of orbicularis oculi, blink reflex and brain stem auditory evoked potential were studied in 12 blepharospasm patients before BTX therapy, 9 patients after BTX therapy and 9 age and sex matched healthy controls. The mean amplitude of orbicularis oculi in patients was significantly lower before BTX therapy (p < 0.05) and after BTX therapy (p < 0.02). The amplitudes of R1, R2 and contralateral R2 (CR) was higher in patients than controls but did not reach statistical significance. Following BTX therapy there was a reduction in amplitude of R1, R2 and CR (p

Twenty-two patients with Parkinson's disease (PD) were studied by clinical evaluation, assessments of dementia and depression, as well as electrophysiologic examinations for blink reflex (BR), cortical somatosensory evoked potentials (CSEP), brain stem, and long-latency auditory evoked potentials (BAEP, and LAEP), and cerebrospinal fluid (CSF) assays for monoamine metabolites. Results show that PD patients have a significant decrease of Mini-Mental State Examination (MMSE) scores (p < 0.05) and an increase of Hamilton Depression Scale (HDS) scores (p < 0.01), as well as a longer latencies of R2 in BR, N19 and P22 in CSEP, W4 and W5 in BAEP and P300 in LAEP (p < 0.01), and lower CSF levels of HVA and MHPG (p < 0.05). The findings suggest a correlation between dementia/depression and mesocorticolimbic and mesostriatocortic dysfunction with dopaminergic and noradrenergic deficiencies in PD patients. Furthermore, parkinsonian dementia parallels the length of duration of the disease, but not the severity of motor disability. Parkinsonian depression parallels both the length of duration of the disease and the severity of motor disability.

Thirty-two Japanese patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) were studied by means of the electrically elicited blink reflex and three responses (R1, R2, R3) were registered. 69% of the patients displayed a uni- or bilateral crossed R1 response (R1k) as compared to 11% in the control group. A positive correlation between R1k and an exaggerated jaw jerk reflex was found in the patients. Central abnormalities of the nervous system with diminished presynaptic inhibition acting in the interneuronal input of the brainstem of HAM/TSP patients was the most likely cause. It could lead to the unmasking of crossed trigemino-facial pathway reflex which is present in the normal population from birth. These results strongly support the supraspinal involvement of the central nervous system (CNS) in HAM/TSP more than usually thought.

The neurologic states and activities of daily life of patients with Parkinson's disease were evaluated using a rating scale with subitems, and subsequently the neurologic disturbance scores and the daily activity impairment scores were obtained. Subjects consisted of 19 normal controls, and 55 ambulatory patients without marked dyskinesia who were on various anti-parkinsonian drugs. Blink reflex was elicited by paired electrical stimulation over the supraorbital nerve. The interval time between the conditioning stimulation and the test stimulation was set at 200 ms, and 5 serial ipsilateral maximal R2 amplitudes on the stimulated side were measured. The mean of the paired maximal R2 amplitude ratio (test/conditioning), expressed as a percentage, was defined as the habituation index. The habituation indices in normal controls and those with Parkinson's disease were 17.1 +/- 7.6 and 51.9 +/- 29.3, respectively (P less than 0.01). The degree of akinesia, rigidity, balance/gait and dysarthria was positively correlated with the habituation index (P less than 0.01), while tremor was not. On the whole the habituation index was found to have a significant correlation not only with the neurologic disturbance score but also with the daily activity impairment score (P less than 0.01).

Despite many new developments and studies, multiple Sclerosis (MS) is still difficult to diagnose. Magnetic resonance imaging (MRI) is an important aid in the patients clinically diagnosed as MS. Functional assessment of the patient’s symptoms increases the importance of neurophysiological methods, especially in cases with negative MRI findings. Impulse conduction in MS as a result of demyelination in the central nervous system fibers changes and delays. In this study, we compared blink reflex (BR) which is a neuropsychological methods with MRI examination. We aimed to determine the relationship between the BR abnormalities and lesion localization and their values in the diagnosis of MS. We studied 21 patients (mean age 33 ± 9 years; 7 men and 14 women) and 33 age-matched healthy subjects (mean age 34 years, 19 females and 14 males). MRI and BR were studied in all the subjects. BR showed abnormalities in 66.7% of patients and these abnormalities were apparent in the brainstem lesion. We conclude that BR, which can be easily and rapidly performed in an EMG laboratory can provide useful and objective information about in particular the brainstem lesions.

WCN 2013 No: 907 Topic: 36 — Other topics Compressed sensing technology could accelerate MRI at 7 T G. Zhang, G. Xiao, Z. Dai, S. Li, R. Wu. Shantou University Medical College, Shantou, China; Math and Applied Mathematics, Hanshan Normal University, Chaozhou, China Background: Compressed sensing is an innovative theory of signal acquisition and processing based on the areas of applied mathematics. It works by using the mathematical algorithm to make an appropriate domain transformation for the collected signals and changing them into sparse or compressible signals. Afterwards, gathering the compressed signals directly to reconstruct the original signals at speedy, fine quality by themethod of reconstruction algorithm. Due to its excellent temporal resolution advantages and satisfactory temporal resolution, compressed sensing has become a research hotspot in the field of medical imaging. Objective: Based on the compressed sensing image reconstruction algorithm, we aim to use less data to obtain high quality reconstructed images which is good to accelerate medical imaging speed and reduce the radiation. Material and methods: We firstly make a sparse representation of the image scanned at 7 T via a multiscale wavelet transform by using MATLAB. After being compressed, the retained energy is 99.29%, and the number of zeros is 93.73%. That is, by wavelet transformation, most coefficients are small though nearly all the image pixels have nonzero values. Then we use the histogram method of the original image and synthesized image and make sure that the step of compression is significant. Finally, we reconstruct the image by the way of sequential minimal optimization. Conclusion: This method will be significant to achieve rapid high quality imaging in MRI at 7 T and it can reduce the cost during processing, storage and transmission. doi:10.1016/j.jns.2013.07.2116 Abstract — WCN 2013 No: 888 Topic: 36 — Other topics Blink reflex excitability in patients with fibromyalgia syndrome WCN 2013 No: 888 Topic: 36 — Other topics Blink reflex excitability in patients with fibromyalgia syndrome M.U. Aluclu, A.D. Turhanoglu. Neurology Department, Dicle University, Diyarbakir, Turkey; Department of Physical Medicine and Rehabilitation, Mustafa Kemal University Hospital, Hatay, Turkey Objective: We aimed to investigate the blink reflex excitability in fibromyalgia syndrome. Subjects and methods: A total of 23 women with FMS and 14 healthy female controls were studied. Blink reflexes were elicited by electrical stimulation of the supra-orbital nerve. The stimuli were applied at first single stimulus and then paired stimulus by using ISIs by 100–600 ms. Electromyography signals were recorded from the right orbicularis oculi muscle. Results: There are significant differences between FMS and controls in responses obtained by paired stimulus at 200–400 ms. Responses of R2 obtained by ISI at 100–400 ms were smaller than those obtained by single stimulus in controls. This inhibition disappeared in response to paired stimulus by 500, 600 ISI in controls. Yet, in FMS patients, this expected inhibition only appeared for iR2 and cR2 obtained at 100 ms ISI and then did not appear at the paired stimulus at 200–400 ms ISIs. Conclusions: Lack of BR R2 response inhibition to paired stimulus by ISIs might be an electrophysiologic evidence that indicates central sensitization in FMS. doi:10.1016/j.jns.2013.07.2117 Abstract — WCN 2013 No: 881 Topic: 36 — Other topics Semantic abilities in children with dyslexia S.M. Golubovic, S. Tubin. Faculty of Special Education and Rehabilitation, University of Belgrade, Belgrade, Serbia The goal of this research was to deduct the frequency of dyslexia and achievement of children with dyslexia on the Test of Short-term Verbal Memory, Test of Dominant Lateralization, Triage Articulation Test, Semantic Test, and Test of Voice Analysis and Synthesis. Methodology: From a total of 280 children which were tested at the end of the second, third and fourth grade, with the analysis of handwriting (dictation, explanation of what was happening, transcription), 38 children (13.57%) were singled out with dysgraphia, from which 57.9% with dyslexia and 42.1% with motor dysgraphia. They are all tested with the Tridimensional Reading Test (Helen Sax), and for this sample it singled out 25 (8.9%) children with dyslexia. From the total number of dyslexic children, 88% have dyslexic dysgraphia, and the remaining 12% have graphomotor problems. Children with intellectual dispairment, bilingual children, as also socio-educationally ignored children, are excluded from the research. Results: The best results were shown on the test of metonymswherein 80% of children gave all the answers, and 20% were partially successful, which means, there were no unsuccessful children. There were no incompletely unsuccessful children on the test of homonyms, but 60% of children have given just 2 of the expected 4 answers. On the test of antonyms there were 44% unsuccessful children. The test of synonyms has especially bad results, because 48% of children didn't give any answer, and 24% of children have given just one answer, meaning, only 28% have done well in this part of the test. doi:10.1016/j.jns.2013.07.2118 Abstract — WCN 2013 No: 873 Topic: 36 — Other topics Determination of expression pattern of big-H3 gene in the process of regeneration in a model of zebrafish eye cryoinjury WCN 2013 No: 873 Topic: 36 — Other topics Determination of expression pattern of big-H3 gene in the process of regeneration in a model of zebrafish eye cryoinjury G. Ahmedova, F. Yunusov, G. Rakhimbaeva. Neurology, Tashkent Medical Academy, Tashkent, Uzbekistan Introduction:Humans have a rather limited capacity to regenerate after injury, while other vertebrates such as the zebrafish are capable of regenerating many anatomical structures. One of them is transforming growth factor beta induced regeneration (initially called BIGH3, BIG-H3), which signals have emerged as one of the components of the inductive process. Our investigation focused on the role of BIGH3 in the process of retinal regeneration in zebrafish after cryoinjury, wherein it was important to establish its pattern of expression. Materials and methods: ABTL wild type zebrafish strains of both sexes 10–14 months of age were bred in standard fish facility conditions. In total, 45 zebrafish were used for the investigation of the process of regeneration in the retina. 40 of them were subjected to cryoinjury. Postinjury measurements were grouped into the following periods: 1 day postinjury (dpi), 2 dpi, 3 dpi, 5 dpi, 7 dpi, 15 dpi, 21 dpi and 28 dpi. RNA from retina was obtained by using the TRIZOL reagent. RNA concentrations and purity were measured using UV-spectrophotometry. Equal amounts of RNA were reverse transcribed into cDNA using StrataScript reverse transcriptase. Quantitative RT-PCR was performed for each sample in duplicate, using β-actin primers as control. Results: Pronounced upregulation of the expression was observed at 5 dpi. At 7 dpi, BIGH3 expression reached the highest point as Abstracts / Journal of the Neurological Sciences 333 (2013) e579–e628 e607

WCN 2013 No: 1729 Topic: 36 — Other topic Blink reflex excitability abnormalities in multiple sclerosis C. Cabib, E. Martinez-Heras, S. Llufriu, J. Casanova-Molla, Y. Blanco, A. Saiz, J. Valls-Sole. EMG Unit, Neurology Department, Hospital Clinic, University of Barcelona, Spain; Center for Neuroinmunology, Neurology Service, Hospital Clinic Barcelona and Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain Background: Brainstem dysfunctions in multiple sclerosis (MS) may be caused by either local brainstem lesions or changes in excitability modulation from supranuclear inputs. We hypothesized that while brainstem lesions lead to abnormalities in latency of BR (AbLat), supranuclear lesions lead to abnormalities in excitability measures (AbExc). Objective: To assess abnormalities in BR excitability in MS patients and their correlation with MRI-supranuclear lesions. Patients and methods: In 20 patients and 10 control subjects, we measured latencies and area of R1, R2 and R2c to single unilateral supraorbital stimulation of either side. We calculated the R2c/R2 ratio as a measure of asymmetric excitability enhancement. Patients were classified as having AbLat or AbExc when the values were above the mean + 2SD of our control group reference data. Brainstem and hemispheres (hLL) MRI-lesion load were measured with computer-assisted software (FSL). T-test and Spearman's test were used for statistics. Results:AbLatwere found in 8 patients (7 of them had pontomedullary lesions). AbExc were found in 7 out of the remaining 12 patients. In these patients, a significantly larger R2c/R2 ratio (p = 0.03 with respect to controls) coincided with a significant enhancement of R1 amplitude (p = .0001 with respect to the contralateral side). They also showed a positive correlation between R2c/R2 ratio and ipsilateral hLL (r = 0.357), but only one had a lesion that compromised the trigeminal-facial circuit. Conclusion: Asymmetric BR excitability enhancement correlates with unilateral brain lesions in MS. These tests add information for the functional evaluation of the effects of brain LL on brainstem circuits. doi:10.1016/j.jns.2013.07.2280 Abstract — WCN 2013 No: 2141 Topic: 36 — Other topic Homozygosity for P.Cys183ser mutation in Notch3 gene may influence the severity of clinical presentation? Report of an Italian family S. Bianchi, A. Rufa, C. Vinciguerra, G.N. Gallus, M.T. Dotti, A. Federico. Department of Medical, Surgical and Neurological Sciences, University of

Trigemino-cervical reflexes, recorded from the semispinalis capitis muscle (SCM) in the posterior neck, were studied in 35 healthy volunteers, in response to electrical stimulation of the supraorbital trigeminal nerve and glabellar tapping. Simultaneous responses evoked from the ipsilateral orbicularis oculi muscle (OOM) were also recorded i.e. blink reflexes. Electrical stimulation of the supraorbital nerve elicited a reflex response with a latency of about 50 ms from the ipsilateral SCM which was called C3. An early reflex response, which sometimes had two components with latencies of 18 ms and 35 ms, was elicited with glabellar taps. They were called C1 and C2 respectively. When C1 and C2 were elicited with usual glabellar taps, C3 was suppressed. With electrical stimulation, suppression of C1 and C2 was noted, though C3 could easily be obtained. Electrophysiological characteristics of C1 (and C2) were compatible with an oligosynaptic, innocuous reflex, whereas C3 seemed to be multisynaptic and nociceptive in nature. A negative interaction between these two reflexes was observed.

Fifty patients with Bell's palsy and 30 patients with etiologically different symptomatic peripheral facial nerve palsy were studied by means of electrically evoked blink reflexes 1-23 days after onset of paresis. Their results were compared with a normal control group of 30 healthy subjects. In a significant number of patients (64% in Bell's palsy and 53% in symptomatic facial nerve palsy) a contralateral early blink reflex response (R1) could be elicited upon stimulation of the normal side as compared to 13% in the control group. It is suggested that this result may be explained by synaptic reorganization of the facial nucleus leading to functional unmasking of pre-existing crossed trigemino-facial reflex pathways during regeneration. This view is in line with previous experimental data in animals on the time course of structural changes in the facial nucleus after lesioning of the ipsilateral facial nerve.

Patients with hemifacial spasm (HFS) have an abnormal muscle response (AMR) that can be elicited by stimulating one branch of the facial nerve and recording electromyographically from muscles innervated by other branches of the facial nerve. In addition, the R1 component of the blink reflex can be elicited from the affected side in patients with HFS who are undergoing microvascular decompression (MVD) operations under inhalation anesthesia. A synkinetic component of the blink reflex response that corresponds to the R1 component can be recorded from the mentalis muscle. In the present study we show that the blink reflex elicited by electrical stimulation of the supraorbital nerve can suppress the AMR elicited by electrical stimulation of the temporal branch of the facial nerve in patients with HFS when the interval between stimulation of the supraorbital nerve and stimulation of the temporal branch of the facial nerve (interstimulus interval, ISI) is such that the blink reflex response would appear later than the AMR if they had been elicited independently. Within a short range of ISIs the two responses suppress each other partially or totally. We find evidence that the suppression of the AMR is the result of an interaction in the facial motonucleus. We believe that the results of the present study support the hypothesis that the facial motonucleus is hyperactive in patients with HFS, and we suggest that the AMR is a result of backfiring from the facial motonucleus and that it may thus be an exaggerated F-response.

The blink reflex cannot normally be elicited during surgical anesthesia using inhalation anesthetics. However, in patients with hemifacial spasm (HFS) the early component of the reflex response (R1) can be elicited on the affected side but not on the unaffected side during such anesthesia. The electromyographic (EMG) response from the mentalis muscle to stimulation of the supraorbital nerve was recorded during microvascular decompression (MVD) of the facial nerve to relieve HFS and compared to the response from the same muscle to stimulation of the zygomatic branch of the facial nerve in four patients. During the operation before the facial nerve was decompressed, contractions in both the orbicularis oculi and the mentalis muscles could be elicited by stimulation of the supraorbital nerve (mean latencies 12.2 ± 1.9 and 12.9 ± 2.0 ms, respectively). When the facial nerve had been decompressed the blink reflex could no longer be elicited, and there was no response from the mentalis muscle to stimulation of the zygomatic branch of the facial nerve. Compound action potentials (CAP) recorded from the 7th cranial nerve in response to stimulation of the supraorbital nerve had latencies of 7.5 ms ± 1.4 ms to the negative peak.

The pathway of the blink reflex, elicited by auditory stimulation, was investigated electrophysiologically. The reflex was recorded as microvibrations of the eyelid and was named the auditory-evoked eyelid microvibration (AMV). Pharmacophysiological studies suggest that AMV is closely related to the midbrain reticular formation and studies of electrical lesions in the midbrain reticular formation support this. Lesions in several parts of the central nervous system provide evidence that the inferior colliculus has an important role in AMV, and the cerebral cortex may have an inhibitory influence. Studies of brainstem transections indicate that the reflex pathway of AMV exists between the lower midbrain and the upper medulla. Because of its ease and simplicity, AMV is believed to be a useful test for evaluation of the function of the brainstem.

A blink reflex consists of an early unilateral component, R 1 , and a late bilateral component, R 2 . During an acute phase of hemispheric cerebrovascular accident, R 1 and R 2 were abnormal in 30 and 50 of 66 patients, respectively. Paired stimuli usually corrected R 1 but not R 2 , which was profoundly suppressed. The discrepancy between polysynaptic R 2 and oligosynaptic R 1 indicates a greater disfacilitation at the level of interneurons than at the motoneuron, which serves as the final common path. Abnormality of R 2 occurred bilaterally with stimulation on the affected side of face and contralaterally after stimulation on the normal side in 31 patients. This finding suggests a diffuse loss of internuncial excitability, contralateral to the hemispheric lesion. Changes of R 2 implicated the brainstem pathways forming the afferent and efferent arc of the reflex in 7 and 8 patients, respectively. The remaining 4 comatose patients had no R 2 irrespective of stimulus sites. Clinical localization of the hemispheric lesion showed no consistent correlation with the type of blink reflex abnormalities. The CT scans revealed widely scattered changes in 29 patients with abnormal blink reflex but with a tendency to overlap in the inferior Rolandic area. This contrasted with conspicuous sparing of the inferior postcentral region in 10 patients with normal blink reflex. These findings suggest the presence of crossed facilitation to this reflex from wide areas of the cortex but most prominently from the sensory representation of the face.

In 30 patients with Parkinson's disease, 55 patients with other neurological disorders and 25 normal subjects, both upper eyelid movements and orbicularis oculi reflexes to repetitive glabella taps were simultaneously recorded using a newly devised apparatus for the measurement of eyelid movement. Upper lid movement during the blink reflex has been thought to correspond to the late component of the two components of the orbicularis oculi reflex, and failure of habituation of the late component to repetitive stimuli has been considered to be responsible for the glabella tap sign. However, the present study showed that the eyelid lowered after the early component (R1), and habituation of the late component (R2) was recognized in 31% of subjects with the glabella tap sign. This shows that there is no direct causal relationship between the glabella tap sign and lack of the habituation of the late component.

A group of 89 patients in whom multiple sclerosis (MS) has been clinically diagnosed with varying degrees of certainty, and 25 patients with optic neuritis (ON), were subjected to the following electrophysiological tests: visual evoked response (VER), auditory brainstem-evoked response (ABER), somatosensory-evoked response (SSER), blink reflex and electronystagmography (ENG). All these patients also underwent computerized tomography (CT scan) and analysis of cerebrospinal fluid (CSF). A new diagnostic procedure is proposed, combining optimum detection of definite MS with optimally economical use of the above-mentioned non-clinical tests. The results for the MS patients show that definite MS can be diagnosed much more frequently (72%) if abnormal results in the above-mentioned tests are accepted as evidence of a (subclinical) CNS lesion. Application of the clinical diagnostic criteria of McAlpine yielded “definite MS” only in 27% of our patient material. Our diagnostic criteria showed evidence for MS in 36% of the patients clinically diagnosed as having ON. The test results were inconclusive as regards the possibility of the remaining ON patients developing MS in the future.

Late responses to percutaneous electrical stimulation of the facial nerve of normal man were studied in single facial motoneurones by means of single fibre EMG recordings. On the basis of latency variation and the relationship to direct responses, late responses could be differentiated in 4 types: reflex responses with small and large latency variation respectively; axon reflexes due to branching of the motor axons, and recurrent responses following antidromic activation of the motor axons. The reflex responses were due to stimulation of neighbouring trigeminal afferents and corresponded to the first and second component of the blink reflex. Axon reflexes indicate that branching of the axons may occur even in the intracranial and perhaps in the intracerebral course of the nerve. Recurrent responses exhibited very small variations in latency; they could be facilitated by subthreshold depolarization of the soma-dendritic membrane.

Although the blink reflex is a standard neurophysiological investigation its relationship with eyelid movement has not been clearly established. We studied normal subjects and patients with unilateral facial paralysis to define the pattern of eyelid movement following glabellar tap, supraorbital nerve stimulation, facial nerve stimulation and direct corneal stimulation. We found that eyelid closure did not necessarily occur in a single movement. Following glabellar tap the first component of a two-stage movement was initiated by levator palpebrae relaxation while with supraorbital nerve stimulation orbicularis oculi contraction produced the first movement. The compound muscle action potential following direct facial nerve stimulation produced only minimal eyelid movement, the major closure being associated with a longer latency orbicularis oculi reflex. Corneal stimulation elicited a single component eyelid movement. Thus, the pattern of eyelid movement differed for each stimulus reflecting variations in orbicularis oculi contraction and levator palpebrae inhibition.

Clinical and electrophysiological observations have been carried out on 12 patients with myotonic dystrophy. Neurological examination showed that the tendon reflexes were absent or weak in almost all cases, whereas the cutaneous reflexes were normal. Examination of both deep and superficial sensibility gave normal results. Electromyography confirmed widespread "myopathic" activity and myotonic discharges were recorded on insertion of the needle electrode and at rest. Motor and sensory conduction velocity in the ulnar nerve and motor conduction in the peroneal nerve proved to be normal. Repetitive supramaximal nerve stimulation showed in 10 cases a decrease in potential amplitude, more evident at higher frequencies of stimulation. In the 2 other cases, by contrast, an increase in amplitude was observed, and this was suggestive of a partial presynaptic block. The jaw reflex was absent in 5 cases and reduced in amplitude in the 7 other cases. The results of blink reflex investigations were normal, with the exception of 2 cases where no early response was elicited. Spinal monosynaptic reflexes were absent in 7 cases after both electrical (H reflex) and mechanical stimulation (T reflex), whereas the response to direct stimulation of nerve motor fibres (the M response) was always present, even though reduced in amplitude. Such data lead one to reject the hypothesis that the absence of deep reflexes is due to pathological change in the muscle spindles. It seems more likely that the selective atrophy of Type 1 muscle fibres, known to be involved in deep reflex responses, is responsible for the early disappearance of the tendon reflexes.

Electrical stimulation of the fibres of the ulnar nerve with hypodermic needles inserted at wrist level was carried out in 17 healthy subjects, in 18 patients with grasp reflex and in 12 hemiplegic patients. The electromyographic activity of the flexor carpi ulnaris (FCU) and biceps (Bi) was recorded using surface electrodes. 1. 1. In the normal subject This stimulus evokes a double polysynaptic reflex response: one is of short latency (35–55 msec), and the other, or nociceptive response, is of longer latency. Stimuli of increasing intensity evoke this double activity first in the FCU and then in the Bi. 2. 2. In subjects with a grasp reflex The distribution of the reflex response to ulnar stimulation changes. The short latency response (R2) of the Bi becomes the first activity to be recorded, and this response is not subject to habituation at a frequency of 1 c/s. 3. 3. During hemiplegia The response pattern is different. Disorganization is centred on the nociceptive reflex (R3) which can be evoked by an abnormally low threshold stimulus. The capacity of discriminating the quality of the stimulation appears to be partially lost. It was therefore possible to observe relatively dissociated modifications of one or the other of the polysynaptic reflex components of cutaneous origin during various motor disabilities. Furthermore the responses in the upper limb can be distinguished from those in the lower on a electrophysiological basis by the importance of the short latency (R2) reflex response (this is probably of tactile origin). This reflex in the upper limb appears to be a contact reflex, the physiological function of which is to bring the limb towards the stimulus.