Unexpected worsening of progressive multifocal leucoencephalopathy following COVID-19 pneumonia.

Progressive multifocal leucoencephalopathy is a serious side effect of natalizumab, a humanized monoclonal antibody approved for the treatment of multiple sclerosis. Here, we report a case of unexpected worsening of natalizumab-related progressive multifocal leucoencephalopathy following COVID-19. After natalizumab discontinuation, a slight neurological improvement was observed, but, two months later the patient was admitted to the hospital because of neurological deterioration and COVID-19 mild pneumonia. Except for SARS-CoV-2 infection, no other potential factors of neurological worsening were identified. Thus, we pose the hypothesis that SARS-CoV-2 was instrumental in the progressive multifocal leucoencephalopathy deterioration.

[The clinical use of the IWG diagnostic criteria for Alzheimer's disease: A retrospective study in a memory clinic]. / L'application en clinique des critères diagnostiques IWG pour la maladie d'Alzheimer: Etude rétrospective dans une clinique de la mémoire.

INTRODUCTION: In recent years knowledge about Alzheimer's disease (AD) presented a major change since the availability of new diagnostic criteria incorporating biomarkers within the known cl inical criteria. Such criteria were elaborated by NIA-AA (National Institute on Aging - Alzheimer's Association) for clinical use and IWG (International Working Group) for research purpose. The aim of this study is to investigate the use of complementary examinations included in the NIA-AA and IWG criteria in a memory clinic characterized by a heterogenous population of patients. METHODS: We retrospectively reviewed patient's characteristics of cases consulting between 01/01/2010 and 31/12/2013 based on the implementation of three additional tests: neuropsychological testing, measurement of cerebrospinal fluid (CSF) biomarkers and brain MRI. Patients were compared according to their origins. RESULTS: 919 patients' medical records were included in the study, 20 % of which were from immigrant background. Non-European Union migrants underwent less neuropsychological testing and more lumbar punctures in comparison with the local population. CONCLUSION: CSF biomarkers allow defining an objective diagnostic component of AD by suppressing the variability due to language, culture, education and the clinical presentation of the disease. Despite the known use in the research domain but not yet validated for clinical use, the IWG criteria are applied in heterogeneous populations with a high percentage of migrants, especially when the results of the neuropsychological testing are poorly contributive. We expect recommendations for clinical use of the CSF biomarkers or better cognitive assessment methods for these populations in the future.

INTRODUCTION: A ce jour, notre vision de la maladie d'Alzheimer (MA) connaît un changement majeur depuis l 'apparition de nouveaux critères diagnostiques incorporant des biomarqueurs aux critères cliniques connus. La NIA-AA (National Institute on Aging - Alzheimer's Association) en a élaboré pour la pratique courante et l'IWG (International Working Group) pour le domaine de la recherche. L'objecti f de cette étude est d'analyser la réalisation des examens complémentaires cités dans les critères NIA-AA et IWG au sein d'une clinique de la mémoire rassemblant une population hétérogène. METHODES: Nous avons revu de manière rétrospective les caractéristiques de patients ayant consulté entre le 1/01/2010 et le 31/12/2013 selon 3 paramètres : la réalisation ou non de l'examen neuropsychologique, du dosage de biomarqueurs dans le liquide céphalo-rachidien (LCR) et de l'imagerie par résonance magnétique cérébrale. Les patients ont ensuite été comparés selon leur origine. RESULTATS: Sur les 919 dossiers analysés dans l'étude, 20 % des patients sont issus de l'immigration. Les migrants non européens ont reçu moins d'examens neuropsychologiques et plus de ponctions lombaires que les patients belges. CONCLUSIONS: Les biomarqueurs du LCR permettent de définir une composante diagnostique objective de la MA en supprimant les variables liées à la langue, la culture, la scolarité et l'expression de la maladie. Malgré leur application connue dans le domaine de la recherche mais actuellement non validée en clinique, les critères IWG prédominent en pratique dans les populations hétérogènes comprenant un haut taux de migrants lorsque les examens neuropsychologiques sont peu contributifs. Des recommandations d'utilisation des biomarqueurs du LCR en pratique courante ou des outils d'évaluation cognitive plus performants dans ces types de population sont attendues.

The relation between the symbol digit modalities test, fatigue, depression, and anxiety symptoms in a Belgian MS cohort.

BACKGROUND: Multiple sclerosis (MS) is associated with high prevalence of cognitive impairment, ranging from 40 to 80%. The purpose of this single-center retrospective study was to examine the relation between cognitive function, as measured by Symbol Digit Modalities Test (SDMT), with fatigue, anxiety, and depression symptoms in a Belgian cohort of patients with MS. METHODS: Sociodemographic and clinical data were analyzed in 66 (F:40, M:26) Belgian patients with a diagnosis of MS. The cognitive function was assessed with the oral version of SDMT, depression and anxiety symptoms with the Hospital Anxiety and Depression scale (HAD), fatigue symptoms with the French valid version of the Fatigue Impact Scale in MS (EMIF-SEP), which is a scale composed of four dimensions (cognitive, physical, social, and psychological) allowing a multidimensional evaluation of fatigue. RESULTS: The multivariate linear regression analysis demonstrated that lower SDMT scores were associated with higher EDSS score and psychological dimension of fatigue symptoms. No association were found between SDMT and anxiety or depression symptoms. Conversely, higher depression and anxiety symptoms were associated with higher total fatigue symptoms, but lower physical dimension of fatigue symptoms. Higher anxiety symptoms were also independently associated with higher social dimension of fatigue symptoms. CONCLUSION: A complex relationship exists between cognitive performance, fatigue, and neuropsychiatric symptoms in Belgian people with MS. The level of disability and fatigue adversely affects the cognitive function in MS, whereas depression and anxiety seem to not have a significant effect. A more complex relationship exists between fatigue and neuropsychiatric symptoms, with a divergent interplay between the different dimensions of fatigue that supports the multidimensional approach to assessing fatigue in MS.

[Frontal syndrome post cerebral malaria. Case report]. / Un cas de syndrome frontal post-neuropaludisme.

Cerebral malaria is one of the most serious complications of Plasmodium falciparum infection, this protozoa of the Plasmodium family is the only known to induce cerebral malaria. This case is about a frontal lobe syndrome post cerebral malaria in a young man living in an endemic malaria area. This complication is rare and most common during childhood.

Electrophysiological assessment of the effect of intrathecal baclofen in spastic children.

OBJECTIVES: To evaluate the effect of intrathecal baclofen in a group of spastic children using electrophysiological procedures described in adults. METHODS: Six children (aged 1-14 years) with severe spasticity of various aetiologies underwent transcranial magnetic stimulation, H reflex and flexor reflex studies before and after intrathecal injection of baclofen. Ashworth scale was used for clinical evaluation of spasticity. RESULTS: Motor evoked potentials, present in two patients before baclofen, were preserved after injection. Before baclofen, H reflex was present in 5 patients (H(max)/M(max) from 0.23 to 0.84) and absent in one who had infantile neuroaxonal dystrophy. After baclofen, it was absent in 4 patients and markedly reduced in one. Surface of flexor reflex significantly decreased after baclofen (P=0.01), while threshold significantly increased (P=0.003). CONCLUSIONS: In spastic children, the action of baclofen on spinal pathways may be quantified by the same electrophysiological procedures as in adults. This approach may contribute to select optimal dosage.

Facilitation of motor evoked potentials in ischemic stroke patients: prognostic value and neurophysiologic correlations.

OBJECTIVE: To investigate the predictive value of paired transcranial magnetic stimulation (TMS) at rest in stroke patients in comparison with the predictive value derived from data obtained by single TMS during facilitation. METHODS: Fifty-six patients with a single ischemic lesion and no electromyographic responses from single TMS in the resting affected hand muscles participated in the study. TMS assessment was performed 32 days post-stroke. It consisted of a single stimulation at maximal output during facilitation (controlateral hand grip and elbow flexion) and a paired-pulse stimulation at rest with two stimuli at maximal output at interstimulus intervals ranging from 15 to 100 ms. Two blind clinical assessments using the 'motricity index' were carried out 26 and 76 days post-stroke. RESULTS: Thirty-seven percent of patients were responsive to single TMS during facilitation, had better clinical scores at both evaluations and better clinical recovery. Fifty-four percent of patients responded to paired TMS, had better clinical scores at the second evaluation and better clinical recovery. All patients who responded to the single stimulation paradigm also responded to the paired one. CONCLUSIONS: A positive correlation was found between the responsiveness to both the TMS paradigms (facilitation procedure and paired stimulation) and clinical recovery. This underlines the importance of facilitation during single TMS in stroke patients and suggests that paired TMS at rest might supplement this procedure in stroke studies.

Electrophysiology of spatial scene analysis: the mismatch negativity (MMN) is sensitive to the ventriloquism illusion.

OBJECTIVES: The ventriloquism effect is the tendency to underestimate the spatial separation between synchronous auditory and visual signals moderately separated in space. If, as it is thought, this effect is pre-attentive, it could modulate the mismatch negativity (MMN) that indexes the automatic, pre-attentive detection of deviant auditory stimuli rarely occurring in a sequence of standard stimuli. We assessed the existence of an MMN evoked by auditory and visual signals made up of standard sounds coming from the same location as the visual signal and deviant sounds coming from lateral deviations (20 or 60 degrees). As first observed in a behavioral study, a ventriloquism effect occurred for 20 degrees spatial separation but not for 60 degrees. METHODS: Cortical evoked potentials were recorded using the oddball paradigm on 8 adults in auditory alone and audiovisual conditions. RESULTS: In the auditory alone condition, each spatial localization contrast elicited a significant MMN. In the audiovisual condition, a significant MMN was only evoked for the 60 degrees contrasts. CONCLUSIONS: The MMN evoked by spatial separation contrasts (20 and 60 degrees) in the auditory alone condition was suppressed by the corresponding audiovisual condition only when the latter yielded a ventriloquism effect, suggesting that this effect occurs at an early perceptual level.

Transcranial magnetic stimulation and other evoked potentials in pediatric multiple sclerosis.

In children, multiple sclerosis is rare and has some clinical and paraclinical differences compared with adults. The assessment of corticospinal motor tracts is expected to be relevant because of their frequent early involvement in this disease. Reported are the results of transcranial magnetic stimulation in two children who presented at 12 and 9 years of age with clinically probable and definite multiple sclerosis, respectively. In Patient 1 the excitatory cortical threshold for the upper limbs was abnormally raised. In Patient 2 the latency of the motor-evoked potentials was considerably increased for the right tibialis anterior muscle, with a slowing of the central conduction time. Although these abnormalities may be consistent with central conduction impairment, they may alternatively suggest early axonal damage because irreversible axonal lesions occurring at the onset of the disease have recently been reported. Testing of central motor tracts, in addition to visual, auditory, and somatosensory pathways, therefore appears appropriate in the multimodal assessment of pediatric patients with suspected multiple sclerosis.

Anterior spinal artery syndrome after aortic surgery in a child.

Anterior spinal artery syndrome is rare in children. In adults, where it is observed most frequently after resection of thoracoabdominal aortic aneurysms, spinal magnetic resonance imaging is considered the first-line investigation to confirm the clinical diagnosis. A 3-year-old male who presented with this syndrome after palliative cardiac surgery for a complex cardiac malformation associated with aortic coarctation is presented. Clinical diagnosis of anterior horn cell impairment below the L2 level was confirmed by electromyography and F-wave studies. Sparing of dorsal sensory tracts was documented by normal somatosensory-evoked potentials, which confirmed the anterior localization of the lesion. Spinal magnetic resonance imaging performed on day 15 and day 105 after surgery was normal. Neurologic deficits, including flaccid paraplegia, remained stable except for the reappearance of patellar reflexes on day 83. Neurophysiologic conduction studies were consistent with lower motoneuron loss. In this patient, magnetic resonance imaging was less sensitive in demonstrating spinal cord lesion than clinical neurophysiology. Somatosensory-evoked potentials failed to detect the insult. Prevention may therefore require other neurophysiologic monitoring techniques.

[Horner's syndrome associated with Guillain-Barré syndrome]. / Syndrome de Claude-Bernard Horner associé à un syndrome de Guillain-Barré

Autonomic dysfunctions are classically described during the acute phase of Guillain-Barré syndrome (GBS). This involvement concerns visceral afferent, parasympathetic and/or sympathetic efferent fibers and is closely related to sudden deaths in the acute phase of the disease. We report a case of a patient suffering from a GBS associated with a transient Horner syndrome without extraocular muscle involvement. Pharmacological tests of the pupils pointed to an orthosympathetic pre-ganglionic disturbance. Neither clinical nor electrophysiological parameter suggested a broader involvement of the autonomic nervous system.

[Lower limb monoplegia and dissociated hypoesthesia after peridural anesthesia]. / Monoplégie du membre inférieur et hypoesthésie dissociée après une anesthésie péridurale.

Neurological sequelae reported after epidural anesthesia include epidural hematoma, spinal cord ischemic injury and lumbosacral nerve root injury. We describe here a case of monoplegia of the right lower limb associated with an ipsilateral loss of perception of pain and temperature following an epidural anesthesia. MRI was compatible with a right centrolateral infarction in the gray matter of the spinal cord below D8. Hypotension, vascular spasm, trauma, arteriosclerosis, pressure increase in the epidural space are potential causative mechanisms. Unilateral symptoms might result from injury to a sulcocommissural artery or an anterior spinal artery when duplicated.

Sensory recovery after microsurgical repair of digital nerves.

The authors study 65 cases of repair of digital nerve lesions performed in 60 patients. They evaluate the quality of sensory recovery by clinical (Dellon and Weber Tests) and electrophysiological tests (velocity, amplitude and duration of the Compound Sensory Action Potential). The results show a complete recovery in 26%, a recovery of discrimination sensitivity in 73.8% and a recovery of protective sensation in 96.9% of the cases. Age and severity of the associated trauma are the most important factors influencing the quality of the sensory recovery.

[Sleep studies in adults: interest in snoring disorders and the sleep apnea syndrome]. / Les études de sommeil chez l'adulte: intérêt dans la ronchopathie et dans le syndrome d'apnée du sommeil.

The authors review the concept of sleep apnea syndrome in adults. A description of a polysomnigraphic study is given. Personal results in a population of obese heavy snorers are summarized.

[Contribution of polysomnography in the assessment of patients with chronic obstructive bronchopneumopathy]. / Apport de la polysomnographie à la mise au point des malades atteints d'une bronchopneumopathie chronique obstructive (BPCO).

15 COPD patients underwent a polysomnographic study demonstrating poor quality of sleep, a mean of SAO2 of 88.8 +/- 3.9% and a apneic-hypopnea index (AHI) of 5.7 +/- 11.8. AHI was higher in sleep stages I and II than in REM sleep. SAO2 showed a progressive drop when going from an awake stage to REM sleep. Respiratory events responsible for the most important desaturation where mostly observed in REM sleep and corresponded in 8 patients to obstructive events (overlap syndrome). The lower mean SAO2 in REM probably explains the best the importance in desaturation related to the respiratory events (Hb dissociation curve). Ear oximetry recordings however interesting are not able to quantify and recognise correctly the respiratory events. Therefore a polysomnographic study remains necessary in order to diagnose adequately the overlap syndrome.

Yield of training exchanges between Europe and Sub-Saharan Africa.

Opportunities that allow neurologists-in-training from Western Europe and Sub-Saharan Africa to benefit from exchanges between their respective neurological departments are rare. In a pilot exchange program, we compare the patterns of neurological diseases encountered in neurological wards of public hospitals in Brussels and Yaoundé to underline educational benefits. For 5 months the age, sex, mortality, HIV cases and clinical characteristics of admitted patients were prospectively analyzed. Eighty Cameroonian and 105 Belgian patients were classified into the following neurological entities: infectious, vascular, immune-related, epileptic, degenerative, neoplastic, psychogenic and movement disorders. Means and proportions were compared using Student's test and Fisher's exact test, respectively. Patients were younger in Yaoundé (mean age 45.3 vs. 54.0 years, p = 0.002), but died four times more (23.75 vs. 4.75 % of admissions, p < 0.001). HIV proportion was 43.75 % in Yaoundé and nil in Brussels. Infectious complications were responsible for 100 % of deaths in HIV-positive patients against 44 % in HIV-negative patients (p = 0.0108). The proportions of vascular, neoplastic and movement disorders were comparable. Neurological complications of infections occurred ten times more in Yaoundé (69 vs. 6.7 %, p < 0.0001). Multiple sclerosis accounted for 11.4 % of admissions in Brussels but other immune-related diseases were more frequent in Yaoundé (8.75 vs. 2 %, p = 0.04). Epileptic, degenerative and psychogenic diseases were more frequent in Brussels: 38.1 versus 12.5 % (p < 0.001), 16.2 versus 5 % (p < 0.0194) and 3.75 versus 14.3 % (p < 0.0224), respectively. Exchanges between Western Europe and Sub-Saharan neurological wards could offer neurologists-in-training firsthand experience with diseases seldom met; otherwise, an understanding of different healthcare systems and a better understanding of the concept of neurology as a public health challenge.

The H reflex as a diagnostic tool for Miller Fisher syndrome in pediatric patients.

Miller Fisher syndrome (MFS) is characterized by gait ataxia, external ophthalmoplegia and areflexia. Immunohistochemical studies suggest a pathophysiological role for anti-GQ1b antibodies at the paranodal regions of the oculomotor nerves, at some neurons of the dorsal root ganglia (DRG) and at motor nerve terminals. The variability of abnormal electrophysiological findings reported is significant. Nerve conduction studies, H reflex and F waves were performed in three pediatric patients with MFS. The H reflex was absent in all three patients. It was the sole abnormality in two patients whereas the third patient also had extended motor and sensory nerve conduction impairments. The transient character of this isolated absence has been confirmed in one patient. These data point to a proximal demyelinating process near the DRG. This may involve selective demyelination of Ia spinocerebellar afferent fibers originating in muscle spindles. In a pediatric practice, the H reflex seems to be a useful tool in the diagnostic approach to MFS.

The role of evoked potentials (EPs) in the assessment of the human central auditory nervous system (CANS).

This paper presents an overview of the use of EPs in the assessment of the CANS. Emphasis is laid on recent developments and research efforts centered on appraising how the auditory neural code is processed by the central pathways. It is shown how, in addition to their classical site-of-lesion testing role, EPs can, especially when combined with ecological (mostly speech-like) stimuli, yield highly valuable information on the neurophysiological processes leading to the perception of auditory objects as well as speech. Special space is devoted to the Mismatch Negativity that currently provides the only objective measure of the accuracy with which the CANS detects auditory and phonetic contrasts.

[Value of monitoring of tracheal respiratory sounds in the diagnosis of nocturnal respiratory dysrhythmias]. / Intérêt du suivi des bruits respiratoires trachéaux dans le diagnostic de dysrythmies respiratoires nocturnes.

Twenty-six patients underwent a polysomnigraphic study allowing sleep staging and respiratory events scoring with the use of the oronasal flow, abdominal, thoracic and total displacement (Respitracet), and ear oximetry. Moreover the patients were also equipped with a tracheal microphone giving a power rectified envelope (sonospirogram). Eleven patients showed abnormal respiratory events that were scored by visual lecture using all respiratory parameters (excluding the sonospirogram) and were classified as obstructive central and mixed apneas-hypopneas. Periodic breathing was also appreciated. Detection of the same events was tried with the sonospirogram alone. The sonospirogram could accurately detect snoring and periodic breathing and finally central obstructive mixed apnea (the apneic index being well correlated: p less than 0.001 as well as the mean apnea duration: p less than 0.005). In contrast hypopneic events related to snoring could not be accurately appreciated. We conclude that a sonospirogram may be useful for the detection of abnormal respiratory events when used alone (screening) as when added to other respiratory signals.