dysdiadochokinese

Dysdiadochokinese (also spelled dysdiadochokinesia) is a neurologic sign characterized by an impaired ability to perform rapidly alternating movements, such as pronation and supination of the hands or rapid finger tapping. It most often points to cerebellar dysfunction, particularly involving the cerebellar hemispheres, and can be unilateral or bilateral depending on the location of the lesion.

In dysdiadochokinese, movements tend to become decomposed and clumsy. Instead of smooth, alternating actions, the sequence may slow, pause, or display an irregular rhythm, with undershoot or overshoot of movements and difficulty maintaining cadence. The sign is usually identified during a cerebellar examination and is often accompanied by other signs of cerebellar disease such as dysmetria, intention tremor, ataxia, nystagmus, or scanning speech.

Assessment is typically performed with rapid alternating movements (RAM). The patient is asked to repeatedly pronate and supinate the hands or to rapidly tap the thigh; slowness, irregularity, or breakdown of the sequence indicates dysdiadochokinese. Unilateral lesions tend to produce the deficit on the ipsilateral side.

Causes include acute or chronic cerebellar pathology, such as stroke, tumors in the posterior fossa, degenerative cerebellar diseases, multiple sclerosis, alcohol-related cerebellar degeneration, and certain vitamin deficiencies. Diagnosis combines neurological examination with imaging, usually MRI, and laboratory studies as indicated to identify metabolic or inflammatory etiologies.

Management focuses on treating the underlying cause and may include coordination-focused rehabilitation. Prognosis varies with etiology and extent of cerebellar involvement.