dysdiadokinesi

Dysdiadochokinesia, also spelled dysdiadochokinesis, is a neurological sign defined by an impaired ability to perform rapidly alternating movements. It most often indicates dysfunction of the cerebellum or its connections and is commonly assessed during the cerebellar portion of a neurological examination.

Clinically, individuals have difficulty with rapid pronation-supination of the hands, fast finger tapping, or alternating foot movements. Movements may be slow, irregular in rhythm, and with variable amplitude. Dysdiadochokinesia is often accompanied by other cerebellar signs such as dysmetria, intention tremor, ataxia, and a broad-based gait.

Causes include acute or chronic cerebellar lesions (such as ischemic or hemorrhagic stroke) affecting cerebellar hemispheres or the vermis, cerebellar degeneration (including spinocerebellar ataxias), demyelinating diseases like multiple sclerosis, chronic alcohol use, thiamine deficiency, or intoxication from sedatives or certain medications. While classically a central sign, dysdiadochokinesia can be influenced by other neurologic conditions as well.

Pathophysiologically, the sign reflects impaired timing, sequencing, and coordination of opposing muscle groups due to cerebellar dysfunction, leading to disrupted rate and rhythm of alternating movements.

Diagnosis is based on clinical examination and history, with imaging (often MRI) used to identify underlying causes. Management targets the underlying condition and may include rehabilitative therapy to improve coordination and balance. The prognosis varies with etiology and the extent of cerebellar involvement.