Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

Anne Fleur Van Rootselaar*, Sandra M.A. Van Der Salm, Lo J. Bour, Mark J. Edwards, Peter Brown, Eleonora Aronica, Johanna M. Rozemuller-Kwakkel, Peter J. Koehler, Johannes H.T.M. Koelman, John C. Rothwell, Marina A.J. Tijssen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar Purkinje cell degeneration and a normal sensorimotor cortex. Subsequently, we sought to explore the nature of cerebellar and motor system pathophysiology in FCMTE. Eye movement recordings and transcranial magnetic stimulation performed in six related FCMTE patients showed impaired saccades and smooth pursuit and downbeat nystagmus upon hyperventilation, as in patients with spinocerebellar ataxia type 6. In FCMTE patients short-interval intracortical inhibition (SICI) was significantly reduced. Resting motor threshold, recruitment curve, silent period, and intracortical facilitation were normal. The neuropathological and ocular motor abnormalities indicate cerebellar involvement in FCMTE patients. Decreased SICI is compatible with intracortical GABAA-ergic dysfunction. Cerebellar and intracortical functional changes could result from a common mechanism such as a channelopathy. Alternatively, decreased cortical inhibition may be caused by dysfunction of the cerebello-thalamo-cortical loop as a result of primary cerebellar pathology.

Original languageEnglish
Pages (from-to)2378-2385
Number of pages8
JournalMovement Disorders
Volume22
Issue number16
DOIs
Publication statusPublished - 1 Dec 2007

Cite this

Van Rootselaar, A. F., Van Der Salm, S. M. A., Bour, L. J., Edwards, M. J., Brown, P., Aronica, E., ... Tijssen, M. A. J. (2007). Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'. Movement Disorders, 22(16), 2378-2385. https://doi.org/10.1002/mds.21738