Cerebellar Motor Disorders

Abstract

Many of the clinical manifestations of cerebellar damage were described at the turn of the nineteenth and twentieth centuries by the pioneers of the cerebellar physiopathology, including Luciani, Babinski, and Holmes. Cerebellar diseases result in lack of coordination and disturbances of accuracy of movements, causing a constellation of symptoms and motor signs which can be grouped into four categories: oculomotor disturbances, speech deficits, deficits of limb movements, and abnormalities of gait and posture. Instability of gaze and nystagmus, hypermetria/hypometria of saccades, saccadic pursuit, skew deviation (ocular misalignment), and disorders of vestibulo-ocular reflex/optokinetic responses are the main oculomotor alterations observed in cerebellar diseases. Gaze-evoked nystagmus is the most common form of nystagmus encountered in disorders of the cerebellum. Ataxic dysarthria has a typical scanning quality; it is often explosive, with a staccato rhythm and a nasal character. Ataxic speech tends to become slow with slurring, and words may be unintelligible. Cerebellar damage typically results in impairment of performance of limb movements. Ataxia of G. Grimaldi (*) Unité d'Etude du Mouvement (UEM), Neurologie -ULB Erasme, Bruxelles, Belgium