Ataxia 

Overview

Ataxia is a neurological condition characterized by impaired coordination and balance due to dysfunction of the cerebellum, the part of the brain responsible for fine-tuning motor control, or due to damage in related sensory or motor pathways. It is a sign, not a disease itself, and can result from various causes, including genetic disorders, stroke, multiple sclerosis, tumors, infections, or toxic exposure. 

Ataxia affects voluntary muscle movements, leading to clumsy or unsteady gait, difficulty with hand coordination, slurred speech, and sometimes involuntary eye movements. It can be acute (sudden onset) or chronic (progressive), and while some causes are reversible, others may lead to permanent neurological impairment. 

Commonly Associated

Ataxia is often associated with several neurological and systemic conditions, including: 

• Cerebellar disorders: Stroke, hemorrhage, tumor, multiple sclerosis. 

• Genetic conditions: Friedreich’s ataxia, spinocerebellar ataxias (SCAs), ataxia-telangiectasia. 

• Toxic exposure: Alcohol, certain medications (e.g., anticonvulsants, chemotherapy agents), heavy metals. 

• Infections: Varicella (chickenpox), Epstein-Barr virus, HIV, prion diseases. 

• Metabolic and nutritional deficiencies: Vitamin E or B12 deficiency, hypothyroidism. 

• Autoimmune conditions: Paraneoplastic cerebellar degeneration, gluten ataxia. 

• Head trauma: Traumatic brain injury affecting the cerebellum or brainstem. 

Causes

Ataxia occurs when the brain, spinal cord, or peripheral nerves involved in movement coordination are damaged or dysfunctional. Major causes include: 

• Cerebellar damage: Most direct cause; the cerebellum integrates sensory input and coordinates movement. 

• Sensory ataxia: Caused by damage to the dorsal columns of the spinal cord or peripheral nerves, disrupting proprioceptive feedback. 

• Vestibular ataxia: Results from inner ear or vestibular pathway disorders affecting balance. 

Specific causes include: 

• Genetic mutations – inherited ataxias such as Friedreich’s ataxia and SCAs. 

• Vascular events – stroke or hemorrhage in cerebellar arteries. 

• Toxic or metabolic insults – chronic alcohol abuse, certain drugs, or deficiencies. 

• Infectious or inflammatory diseases – post-infectious cerebellitis, autoimmune encephalitis. 

• Structural lesions – tumors, abscesses, or congenital malformations. 

Symptoms

Symptoms depend on the cause and part of the nervous system affected but generally include loss of coordination and balance: 

Motor and gait-related: 

• Unsteady, staggering gait (gait ataxia) 

• Poor balance and frequent falls 

• Difficulty with precise movements (e.g., buttoning clothes, writing) 

Limb and trunk coordination: 

• Clumsy hand and arm movements (dysmetria) 

• Overshooting or undershooting targets during movement (intention tremor) 

• Inability to perform rapid alternating movements (dysdiadochokinesia) 

Speech and eye involvement: 

• Slurred, slow, or scanning speech (dysarthria) 

• Abnormal eye movements (nystagmus) 

• Difficulty with smooth pursuit or saccades 

Sensory symptoms (in sensory ataxia): 

• Impaired proprioception (awareness of body position) 

• Worsening balance in the dark or with eyes closed (positive Romberg sign) 

Symptoms often worsen over time in progressive ataxias but may improve with treatment in reversible causes. 

Exams & Tests

Diagnosis requires a detailed neurological evaluation and tests to identify the underlying cause: 

• Physical and neurological examination: 

• Romberg test: Assesses sensory ataxia. 

• Finger-to-nose and heel-to-shin tests: Detect dysmetria. 

• Rapid alternating movement test: Identifies coordination deficits. 

• Imaging: 

• MRI of the brain and spinal cord: Detects cerebellar atrophy, tumors, strokes, or demyelinating lesions. 

• CT scan: For acute hemorrhage or trauma. 

• Blood tests: 

• Check for metabolic causes (thyroid function, vitamin levels). 

• Autoimmune or infectious markers. 

• Genetic testing: 

• Identifies hereditary ataxias such as spinocerebellar ataxia or Friedreich’s ataxia. 

• Nerve conduction studies: 

• Evaluate peripheral nerve involvement in sensory ataxia. 

• Lumbar puncture: 

• Detects infections, inflammatory markers, or paraneoplastic antibodies. 

Treatment

Treatment depends on the underlying cause. While some forms are reversible, others are managed symptomatically to improve quality of life. 

1. Treating Underlying Causes: 

• Vitamin deficiencies: Replace vitamin E or B12. 

• Autoimmune ataxia: Corticosteroids, IV immunoglobulin (IVIG), or plasma exchange. 

• Infections: Appropriate antiviral or antibiotic therapy. 

• Tumors or structural lesions: Surgical removal or radiotherapy. 

• Thyroid dysfunction or metabolic disorders: Specific medical treatment. 

2. Symptomatic and Supportive Management: 

• Physical therapy: Improves balance, strength, and coordination. 

• Occupational therapy: Aids daily living activities and independence. 

• Speech therapy: Helps with dysarthria and swallowing difficulties. 

• Assistive devices: Canes, walkers, or wheelchairs for severe gait instability. 

3. Medications (Symptom Relief): 

• Amantadine or riluzole: May help improve coordination in some patients. 

• Baclofen or clonazepam: For tremors or muscle stiffness. 

4. Genetic Counseling: 

• For hereditary forms, counseling helps families understand inheritance patterns and plan for the future. 

Source 

• Klockgether T. “Sporadic ataxia with adult onset: classification and diagnostic criteria.” Lancet Neurol 2010; 9(1):94–104. 

• Jayadev S, Bird TD. “Hereditary ataxias: overview.” GeneReviews, University of Washington, Seattle, 2023. 

• Finsterer J, et al. “Management of cerebellar ataxia.” Ther Adv Neurol Disord 2020; 13:1756286420937817.