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The Free and Cued Selective Reminding Test (FCSRT) is a largely validated neuropsychological test for the identification of amnestic syndrome from the early stage of Alzheimer’s disease (AD). Previous electrophysiological data suggested a slowing down of the alpha rhythm in the AD-continuum as well as a key role of this rhythmic brain activity for episodic memory processes. This study therefore investigates the link between alpha brain activity and alterations in episodic memory as assessed by the FCSRT. For that purpose, 37 patients with altered FCSRT performance underwent a comprehensive neuropsychological assessment, supplemented by 18F-fluorodeoxyglucose positron emission tomography/structural magnetic resonance imaging (18FDG-PET/MR), and 10 minutes of resting-state magnetoencephalography (MEG). The individual alpha peak frequency (APF) in MEG resting-state data was positively correlated with patients’ encoding efficiency as well as with the efficacy of semantic cues in facilitating patients’ retrieval of previous stored word. The APF also correlated positively with patients’ hippocampal volume and their regional glucose consumption in the posterior cingulate cortex. Overall, this study demonstrates that alterations in the ability to learn and store new information for a relatively short-term period are related to a slowing down of alpha rhythmic activity, possibly due to altered interactions in the extended mnemonic system. As such, a decreased APF may be considered as an electrophysiological correlate of short-term episodic memory dysfunction accompanying pathological aging.

Human brain activity is intrinsically organized into resting-state networks (RSNs) that transiently activate or deactivate at the sub-second timescale. Few neuroimaging studies have addressed how Alzheimer's disease (AD) affects these fast temporal brain dynamics, and how they relate to the cognitive, structural and metabolic abnormalities characterizing AD. We aimed at closing this gap by investigating both brain structure and function using magnetoencephalography (MEG) and hybrid positron emission tomography-magnetic resonance (PET/MR) in 10 healthy elders, 10 patients with subjective cognitive decline (SCD), 10 patients with amnestic mild cognitive impairment (aMCI) and 10 patients with typical Alzheimer’s disease with dementia (AD). The fast activation/deactivation state dynamics of RSNs were assessed using hidden Markov modeling (HMM) of power envelope fluctuations at rest measured with MEG. Correlations were sought between temporal properties of HMM states and participants' cognitive test scores, whole hippocampal grey matter volume and regional brain glucose metabolism. The posterior default-mode network (DMN) was less often activated and for shorter durations in AD patients than matched healthy elders. No significant difference was found in patients with SCD or aMCI. The time spent by participants in the activated posterior DMN state did not correlate significantly with cognitive scores, nor with the whole hippocampal volume. However, it correlated positively with the regional glucose consumption in the right dorsolateral prefrontal cortex (DLPFC). AD patients present alterations of posterior DMN power activation dynamics at rest that identify an additional electrophysiological correlate of AD-related synaptic and neural dysfunction. The right DLPFC may play a causal role in the activation of the posterior DMN, possibly linked to the occurrence of mind wandering episodes. As such, these data might suggest a neural correlate of the decrease in mind wandering episodes reported in pathological aging., info:eu-repo/semantics/published

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered to have potential neuro-invasiveness that might lead to acute brain disorders or contribute to respiratory distress in patients with coronavirus disease 2019 (COVID-19). This study investigates the occurrence of structural brain abnormalities in non-survivors of COVID-19 in a virtopsy framework., info:eu-repo/semantics/published

Published online: 25 April 2018 Background. Electroencephalography (EEG) and magnetoencephalography (MEG) are neurophysiological methods used to investigate noninvasively the spatial, temporal, and spectral dynamics of human brain functions. Objectives. This article reviews data on the use of EEG and MEG for presurgical functional brainmapping in patients with refractory focal epilepsy. The focus is on the localization of the primary sensorimotor (SM1) cortex as well as the verbal language and episodic memory functions. Material andmethods. The English literature was reviewed based on a PubMed search. Relevant references in the selected papers were also included. Results. Presurgical MEG functional localization of the SM1 cortex generally overlaps with intracranial mapping. MEG allows for determination of hemispheric verbal (receptive and expressive) language dominance in neurosurgical patients with a high degree of concordance with the intracarotid amobarbital test. MEG represents an interesting technique for assessing postoperativememory outcome in patients withmesial temporal lobe epilepsy. Very few studies have evaluated the yield of EEG in these three clinical indications. High-density EEG might be a promising technique that needs further validation. Conclusion. MEG is a validated and robust technique for noninvasive functionalmapping of the SM1 cortex and verbal language hemispheric dominance in patients with refractory focal epilepsy. Current data also suggest that MEG is a promising technique for assessing the hemispheric dominance of memory function. Further studies are needed to assess the clinical added value of highdensity EEG in these clinical indications. T. Coolen is a Clinical Master Specialist Applicant to a PhD at the Fonds de la Recherche Scientifique (FRS-FNRS, Brussels, Belgium). A.M. Dumitrescu benefits from financial support of the Fonds Erasme (Research Convention “Les Voies du Savoir”, Brussels, Belgium). M. Bourguignon is supported by the program Attract of Innoviris (grant 2015- BB2B-10), by the Spanish Ministry of Economy and Competitiveness (grant PSI2016-77175-P), and by the Marie Skłodowska-Curie Action of the European Commission (grant 743562). X. De Tiège is Postdoctorate Clinical Master Specialist at the FRS-FNRS. The MEG project at the CUB Hôpital Erasme is financially supported by the Fonds Erasme (Research Convention “Les Voies du Savoir”).

Acute hyperammonemic encephalopathy is a rare but life-threatening condition that might complicate liver disease as well as non-hepatic conditions. It can lead to coma and death, secondary to brain edema and intracranial hypertension. We present three cases of acute hyperammonemic encephalopathy of different etiologies and the observed brain MRI findings. Symmetrical extensive cortical signal abnormalities, typically involving the insular and cingulate cortices, often showing restricted diffusion, are commonly described. These specific imaging features should be recognized by the radiologist since prompt treatment of the condition is paramount., SCOPUS: ar.j, info:eu-repo/semantics/published

Introduction Pulsatile tinnitus is a sound generated by an acoustic source from within the body, which is perceived by the auditory system of the patient. Cases summary We report two puzzling cases of pulsatile tinnitus with normal ENT examinations: the first was due to a cervical internal carotid artery dissection, and the second to the compression of the foramina of Monro by a craniopharyngioma, leading to hydrocephalus. Discussion We review the systematic management and emphasize the decisive role of the ENT clinician regarding this pulsatile tinnitus complaint, because of the potentially severe complications of its underlying pathology.

Fractional flow reserve (FFR) during invasive coronary angiography has become an established tool for guiding treatment. However, only one-third of intermediate-grade coronary artery stenosis (ICAS) are hemodynamically significant and require coronary revascularization. Additionally, the severity of stenosis visually established by coronary computed tomography angiography (CCTA) does not reliably correlate with the functional severity. Therefore, additional angiographic morphologic descriptors affecting hemodynamic significance are required. To evaluate quantitative stenosis analysis and plaque descriptors by CCTA in predicting the hemodynamic significance of ICAS and to compare it with quantitative catheter coronary angiography (QCA). QCA was performed in 65 patients (mean age 63 ± 9 years; 47 men) with 76 ICAS (40-70%) on CCTA. Plaque descriptors were determined including circumferential extent of calcification, plaque composition, minimal lumen diameter (MLD) and area, diameter stenosis percentage (Ds %), area stenosis percentage and stenosis length on CCTA. MLD and Ds % were also analyzed on QCA. FFR was measured on 52 ICAS lesions on CCTA and QCA. The diagnostic values of the best CCTA and QCA descriptors were calculated for ICAS with FFR ≤ 0.80. Of the 76 ICAS on CCTA, 52 (68%) had a Ds % between 40 and 70% on QCA. Significant intertechnique correlations were found between CCTA and QCA for MLD and Ds % (p < 0.001). In 17 (33%) of the 52 ICAS lesions on QCA, FFR values were ≤ 0.80. Calcification circumference extent (p = 0.50) and plaque composition assessment (p = 0.59) did not correlate with the hemodynamic significance. Best predictors for FFR ≤ 0.80 stenosis were ≤ 1.35 mm MLD (82% sensitivity, 66% specificity), and ≤ 2.3 mm(²) minimal lumen area (88% sensitivity, 60% specificity) on CCTA, and ≤ 1.1 mm MLD (59% sensitivity, 77% specificity) on QCA. Quantitative CCTA and QCA poorly predict hemodynamic significance of ICAS, though CCTA seems to have a better sensitivity than QCA. In this range of stenoses, additional functional evaluation is required.

A 76-year-old woman underwent a coronary artery computed tomography angiography (CTA) to exclude coronary occlusive disease after a segmental inferoseptal hypokinesia was discovered at echocardiography in the workup for atypical chest pain. The patient has a body mass index of 40 kg/m2, a history of arterial hypertension, hyperlipidemia, hypothyroidism, and type 2 diabetes. Her drug regimen consists of acenocoumarol, bisoprolol, potassium canrenoate, simvastatin, levothyroxine, and metformin. She also has a history of a second-degree type I atrioventricular block found 18 years earlier during an episode of atrial fibrillation (AF) that has led to several syncopes. A Topaz II pacemaker (Vitatron, Maastricht, the Netherlands) was implanted 10 years ago, replaced 1 year ago, with preservation of the lead, by a Zephyr SR 5620 pacemaker (St. Jude Medical, St. Paul, MN, USA) in the ventricular rate modulated pacing (VVIR mode). The pacemaker control examinations 10 days prior and 6 months after CTA showed a normally functioning stimulator with a virtually permanent ventricular pacing and no alert between both examinations. Stimulation (0.75 then 0.75 V) and sensing (9.6 then 9.3 mV) thresholds and lead impedance (827 then 848 ohms) were within normal ranges and relatively unchanged between both examinations. The activity sensor was turned “on” and the maximum sensor rate was set at 130 beats per minute (bpm). Reaction time was tuned to “fast” and recovery time to “medium.” Stimulation was programmed in the unipolar mode and sensing in the bipolar mode. Battery voltage was 2.79 V with an estimated remaining life of more than 7 years. The 64-row multidetector LightSpeed VCT XT scanner (General Electric, Fairfield, CT, USA)

In Parkinson's disease (PD) the demonstration of neuropathological disturbances in nigrostriatal and extranigral brain pathways using magnetic resonance imaging remains a challenge. Here, we applied a novel diffusion-weighted imaging approach—track density imaging (TDI). Twenty-seven non-demented Parkinson's patients (mean disease duration: 5 years, mean score on the Hoehn & Yahr scale = 1.5) were compared with 26 elderly controls matched for age, sex, and education level. Track density images were created by sampling each subject's spatially normalized fiber tracks in 1 mm isotropic intervals and counting the fibers that passed through each voxel. Whole-brain voxel-based analysis was performed and significance was assessed with permutation testing. Statistically significant increases in track density were found in the Parkinson's patients, relative to controls. Clusters were distributed in disease-relevant areas including motor, cognitive, and limbic networks. From the lower medulla to the diencephalon and striatum, clusters encompassed the known location of the locus coeruleus and pedunculopontine nucleus in the pons, and from the substantia nigra up to medial aspects of the posterior putamen, bilaterally. The results identified in brainstem and nigrostriatal pathways show a large overlap with the known distribution of neuropathological changes in non-demented PD patients. Our results also support an early involvement of limbic and cognitive networks in Parkinson's disease., Highlights • First whole-brain probabilistic tractography study in Parkinson's disease • High quality diffusion-weighted images (120 gradient directions, b = 2500 s/mm2) • Voxel-based group analysis comparing early-stage patients and controls • Abnormal reconstructed track density in the nigrostriatal pathway and brainstem • Track density also increased in limbic and cognitive circuits.