par Grimaldi, Giuliana
Référence Handbook of the Cerebellum and Cerebellar Disorders, Springer Netherlands, page (1597-1626)
Publication Publié, 2013-01
Partie d'ouvrage collectif
Résumé : 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 limbs includes: dysmetria, decomposition of movement, dysdiadochokinesia, cerebellar tremor, isometrAtaxia, disorders of muscle tone (both hypotonia and cerebellar fits), loss of check and rebound, abnormal handwriting, and megalographia. Tremor in cerebellar diseases is mainly composed of low frequency oscillations, usually with a kinetic component. Kinetic tremor is often associated with a concomitant postural tremor. Cerebellar patients have increased body sway and a broad-based stance due to the inability to maintain the body in a stationary position (Ataxia of stance). Similarly, gait in cerebellar patients is irregular and broad based. Successive steps are spaced in a staggering way and followed by corrections or falls. Rhythm is distorted and speed is often reduced. Walking trajectory veers erratically with difficulties in initiation, stops, or turns.