Incoordination

Incoordination, often described as ataxia or dyscoordination, denotes a reduced ability to perform smooth, deliberate movements. It results from dysfunction of the cerebellum and its connections, impaired proprioceptive input from the sensory pathways, vestibular systems, or motor pathways. Clinically, incoordination can affect limb movements, gait, speech, and eye movements, and may be isolated or accompany other neurological signs. Patterns are typically categorized as cerebellar ataxia (limb and/or trunk involvement with decomposition of movement), sensory ataxia (proprioceptive deficit), or vestibular ataxia (gaze instability and vertigo).

Signs and symptoms include dysmetria (overshooting or undershooting movements), dysdiadochokinesia (impaired rapid alternating movements), intention tremor, rebound phenomena, and hypotonia in acute lesions. Gait may be wide-based and unsteady. Nystagmus and vertigo can accompany cerebellar or vestibular involvement, while a positive Romberg test suggests sensory ataxia. Coordinated movement is assessed with tasks such as finger-to-nose, heel-to-shin, and rapid alternating movements.

Common causes span acute intoxication (alcohol, sedatives), cerebrovascular events, tumors, multiple sclerosis, and chronic neurodegenerative disorders (such as spinocerebellar ataxias). Nutritional deficiencies (vitamins B12, E, thiamine), metabolic disturbances, infections, and congenital disorders also contribute. Peripheral neuropathy and vestibular disorders may mimic or contribute to incoordination.

Evaluation combines history, neurological examination, laboratory tests for deficiencies and metabolic issues, and imaging (MRI preferred) when structural lesions are suspected. Management focuses on treating the underlying cause when possible, plus rehabilitation with physical and occupational therapy to improve coordination and safety, along with assistive devices and management of associated symptoms. Prognosis varies by etiology and progression.