ataxias

Ataxia refers to a lack of voluntary coordination of movement, resulting from dysfunction in the cerebellum and its connections. When ataxia is a prominent feature, the condition is described as an ataxia. Presentations include gait ataxia, limb incoordination, dysarthria, and eye movement abnormalities. Ataxias can be hereditary or acquired and may involve the cerebellum, spinal cord, or sensory pathways.

Causes: Hereditary ataxias include spinocerebellar ataxias, largely autosomal dominant, and Friedreich ataxia, autosomal recessive. Many subtypes exist, with onset from childhood to adulthood. Acquired ataxias arise from alcohol or medication toxicity, nutritional deficiencies (notably vitamins B12, E, thiamine), autoimmune cerebellitis or paraneoplastic cerebellar degeneration, infections, metabolic disorders, or toxin exposure. Some ataxias are episodic or related to other neurodegenerative syndromes.

Symptoms: Gait instability, wide-based stance, and falls are common. Limb ataxia causes dysmetria and dysdiadochokinesia. Dysarthria, nystagmus, and ocular pursuit abnormalities may be present. Peripheral neuropathy and proprioceptive loss can accompany cerebellar signs in some forms.

Diagnosis and management: Diagnosis combines clinical assessment with targeted genetic testing for hereditary ataxias and MRI findings of cerebellar or brainstem atrophy. Other tests may include metabolic panels, vitamin levels, autoimmune screening, and CSF studies. Treatment is multidisciplinary and supportive: physical therapy to improve balance, occupational therapy, speech therapy, and management of complications. In some cases, treating the underlying cause may halt progression; for others, symptom management is the focus. Genetic counseling is advised for inherited forms.

Prognosis: Course varies by subtype; many hereditary ataxias are progressively disabling over years. Some forms have slower progression; others involve cardiomyopathy or neuropathy that influences outcome. No cure exists for most ataxias, but interventions aim to maintain function and quality of life.