Elsevier

Revue Neurologique

Volume 163, Issues 8–9, September 2007, Pages 779-791
Revue Neurologique

Revue générale
Neurophysiologie de la dégénérescence corticobasaleNeurophysiology of corticobasal degeneration

https://doi.org/10.1016/S0035-3787(07)91460-5Get rights and content

Résumé

Introduction

La dégénérescence corticobasale (DCB) est une pathologie neurodégénérative associant un syndrome parkinsonien asymétrique doparésistant à une dystonie ou des myoclonies, à une atteinte corticale s’exprimant par une apraxie, un syndrome de la main étrangère ou un déficit sensitif cortical. Le diagnostic de certitude repose encore à l’heure actuelle sur l’examen anatomopathologique. Les critères cliniques proposés dans la littérature restent insuffisants et notamment peu sensibles à la phase précoce de la maladie. Il apparaît donc nécessaire de rechercher d’autres éléments permettant d’orienter le diagnostic du vivant du patient.

État des connaissances

Les techniques d’électrophysiologie permettent l’exploration fonctionnelle des différentes structures cérébrales (corticales et sous-corticales). L’atteinte corticale (frontopariétale) spécifique de la DCB permet de la différencier des autres syndromes parkinsoniens. Ainsi, l’étude des myoclonies apportent des arguments spécifiques pour la DCB. En effet, bien que les caractéristiques cliniques et électromyographiques des myoclonies correspondent à une origine corticale, d’autres éléments classiques (potentiels évoqués géants, potentiel cortical avant la bouffée myoclonique au moyennage rétrograde) sont absents. Une origine sous-corticale est très certainement associée. L’atteinte frontopariétale est également explorée par l’étude des mouvements oculaires. Un allongement isolé de la latence des saccades latérales oculaires, parfois asymétriques permet de distinguer la DCB de la paralysie supranucléaire progressive (PSP). L’atteinte des fonctions cognitives est reconnue de manière récente, mais elle reste parfois difficile à distinguer de celle caractérisant la PSP et les démences frontotemporales. L’étude des potentiels cognitifs permet de confirmer une atteinte sous corticofrontale dès la phase précoce de la maladie. D’autres techniques électrophysiologiques (étude de la dysautonomie, réflexe palmomentonier et réflexe du clignement) apportent des résultats communs aux syndromes extrapyramidaux ou aux synucléiopathies (étude polysomnographique). Elles apparaissent utiles notamment pour appréhender les mécanismes physiopathologiques de ces pathologies.

Conclusion

Les techniques électrophysiologiques apportent une réelle aide au diagnostic de DCB dès la phase précoce en mettant en évidence des anomalies spécifiques relatives notamment à l’atteinte frontopariétale. Elles permettent également d’approfondir les mécanismes physiopathologiques.

Summary

Introduction

Corticobasal degeneration (CBD) is a neurodegenerative disorder of mid- to late-adult life. From a clinical standpoint, CBD is characterized by (i) an insidious onset and a slowly progressing, unilateral, levodopa-unresponsive parkinsonian syndrome with dystonia or myoclonus and (ii) cerebral features such as apraxia, alien limb phenomena and cortical sensory loss. Decisive clinical diagnostic criteria are not available and thus a neuropathological study remains essential for accurate CBD diagnosis. Consequently, additional non-clinical criteria must be identified in order to improve diagnosis while patients are still alive.

Background

Electrophysiological exploration can yield functional information on a number of brain structures (both cortical and sub-cortical) involved in CBD. The disorder features a specific cortical (frontoparietal) alteration which could help with differential diagnoses for other extrapyramidal syndromes. Hence, exploration of a patient's myoclonus can provide some specific arguments for CBD. Indeed, myoclonus displays a number of clinical and electromyographical characteristics which are consistent with a cortical origin (a shorter latency of the cortical C response, for example). However, some typical cortical features are missing (giant somesthesic evoked potentials, and cortical potentials preceding myoclonus in jerk-locked back-averaging studies). Some authors explain these abnormalities in terms of a sub-cortical origin for the myoclonus. The frontoparietal alteration in CBD has also been explored in studies of oculomotor movement. Indeed, asymmetric lengthening of the lateral ocular saccade latency argues more in favour of CBD than progressive supranuclear palsy. Moreover, cognitive function is also compromised in the early stages of CBD, although it is sometimes difficult to distinguish between CBD, PSP and frontotemporal dementia. Studying cognitive potentials enables one to confirm subcorticofrontal abnormalities and to dissociate CBD patterns from PSP patterns. Other electrophysiological tests (such as the exploration of dysautonomia, the palmomental reflex and the blink reflex) produce results which overlap with those seen in extrapyramidal syndromes and synucleinopathies (polysomnography), prompting discussion of the physiopathological mechanisms of these various diseases.

Conclusion

Electrophysiological exploration is of value for diagnosing CBD in general and for studying specific, frontoparietal dysfunctions in particular. These techniques could also significantly contribute to our understanding of the physiopathology of CBD.

Références (73)

  • I. Arnulf et al.

    Respiratory disorders during sleep in degenerative disease of the brainstem

    Rev Neurol

    (2001)
  • I. Arnulf

    Sleep disorders during synucleopathies and taupathies

    Rev Neurol

    (2003)
  • L. Bartolomei et al.

    Transcranial magnetic stimulation of the motor cortex in 6 patients with probable Cortico Basal Degeneration

    Mov Disrod

    (1998)
  • A. Berardelli et al.

    The corneal reflex and the R2 component of the blink reflex

    Neurology

    (1985)
  • V. Bertasi et al.

    Motor cortical hyperinhibition in corticobasal degeneration

    Mov Disord

    (1998)
  • B.F. Boeve et al.

    Corticobasal degeneration and its relationship to progressive supranuclear palsy and frontotemporal dementia.

    Ann Neurol

    (2003)
  • D.J. Brooks

    Functional imaging studies in corticobasal degeneration

    Adv Neurol

    (2000)
  • E.R. Brunt et al.

    Unique myoclonic pattern in corticobasal degeneration

    Mov Disord

    (1995)
  • J.N. Caviness

    Myoclonus and neurodegenerative disease-what's in a name?

    Parkinsonism Relat Disord

    (2003)
  • R. Chen et al.

    Stimulus-sensitive myoclonus in akinetic-rigid syndromes

    Brain

    (1992)
  • N.J. Cordato et al.

    Corticobasal syndrome with tau pathology

    Mov Disord

    (2001)
  • L. Defebvre et al.

    Neurophysiologie des syndromes parkinsoniens

    Rev Neurol

    (2003)
  • A. Delacourte et al.

    Specific pathological Tau protein variants characterize Pick's disease

    J Neuropathol Exp Neurol

    (1996)
  • A. Delval et al.

    Clinical and electrophysiological features of “cortical tremor”

    Rev Neurol

    (2003)
  • G. Deuschl et al.

    Effects of electric and magnetic transcranial stimulation on long latency reflexes

    Experimental Brain Research

    (1991)
  • D.W. Dickson et al.

    Office of Rare Diseases of the National Institutes of Health

    J Neuropathol Exp Neurol

    (2002)
  • D.S. Goodin et al.

    Electrophysiological differences between subtypes of dementia

    Brain

    (1986)
  • N.L. Graham et al.

    Corticobasal degeneration as a cognitive disorder

    Mov disord

    (2003)
  • P. Grosse et al.

    Coherence analysis in the myoclonus of corticobasal degeneration

    Mov Disord

    (2003)
  • A. Homma et al.

    P300 findings in patients with corticobasal degeneration

    No To Shinkei

    (1996)
  • A.J. Hughes et al.

    The accuracy of diagnosis of parkinsonian syndromes in a specialist movement disorder service

    Brain

    (2002)
  • J. Iriarte et al.

    Unilateral periodic limb movements during sleep in corticobasal degeneration

    Mov Disord

    (2001)
  • A. Kertesz et al.

    The corticobasal degeneration syndrome overlaps progressive aphasia and frontotemporal dementia

    Neurology

    (2000)
  • K. Kimura et al.

    Subclinical REM sleep behavior disorder in a patient with corticobasal degeneration

    Sleep

    (1997)
  • T. Kujirai et al.

    Corticocortical inhibition in human motor cortex

    J Physiol

    (1993)
  • R. Kumar et al.

    Cortical-basal ganglionic degeneration

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