Dysmetrie

Dysmetrie, or dysmetria, is a neurological sign characterized by an impaired ability to judge distance or range of a movement. It most commonly presents as hypermetria (overshooting) or hypometria (undershooting) when reaching for a target, and it can affect one limb or several. Dysmetria is a hallmark of cerebellar dysfunction and is often accompanied by other signs of ataxia, such as an intention tremor, dysdiadochokinesia (impaired rapid alternating movements), rebound phenomena, and broad-based gait.

Causes and associations include focal cerebellar lesions from stroke, tumor, or demyelinating disease; degenerative cerebellar disorders such as spinocerebellar ataxias; traumatic brain injury; chronic alcohol use; and certain drugs or metabolic disturbances. Dysmetria can therefore arise from localized cerebellar damage, diffuse cerebellar dysfunction, or temporary cerebellar impairment.

Diagnosis is primarily clinical, based on observation during targeted maneuvers such as the finger-to-nose test and the heel-to-shin test, as well as assessment of rapid alternating movements and stance. Imaging, typically MRI, is used to identify structural lesions when appropriate. The differential diagnosis includes proprioceptive loss and other coordination disorders.

Management focuses on treating the underlying cause when possible and providing supportive rehabilitation. Physical and occupational therapy aim to improve coordination, balance, and functional skills through targeted exercises and compensatory strategies. The prognosis varies with the etiology: recovery may occur after acute cerebellar injury, while progressive degenerative conditions may lead to chronic, long-term impairment.