Physical Examination Tests for Ataxia
The most effective physical examination tests for ataxia include the finger-to-nose test, heel-to-shin test, rapid alternating movements, Romberg test, tandem gait assessment, and observation of normal walking patterns. 1
Types of Ataxia and Clinical Differentiation
Ataxia can be classified into three main types based on the affected neurological structures:
- Cerebellar Ataxia: Affects neural information integration, coordination, and planning
- Sensory Ataxia: Affects proprioception via spinal cord and peripheral sensory nerves
- Vestibular Ataxia: Affects balance and maintenance of equilibrium
Key Differentiation Test
- Romberg Test: Distinguishes between cerebellar and sensory ataxia
- Patient stands with feet together, first with eyes open, then closed
- In sensory ataxia: Significant worsening with eyes closed
- In cerebellar ataxia: Minimal difference between eyes open/closed 2
Standardized Physical Examination Tests
1. Coordination Tests
Finger-to-Nose Test:
- Patient alternately touches their nose and the examiner's finger
- Score: 0 (no ataxia), 1 (ataxia in 1 limb), 2 (ataxia in 2 limbs) 1
- Assesses upper limb coordination and intention tremor
Heel-to-Shin Test:
- Patient slides heel down opposite shin while lying supine
- Evaluates lower limb coordination 1
Rapid Alternating Movements (Dysdiadochokinesia):
- Patient rapidly pronates and supinates hands on thighs
- Assesses ability to perform rapid sequential movements 1
- Particularly sensitive for cerebellar dysfunction
2. Gait Assessment Tests
Normal Walking:
- Observe posture, stability, arm swing, and step length/width 1
Tandem Gait (Heel-to-Toe Walking):
- Patient walks in straight line with heel touching toe
- Highly sensitive for detecting mild ataxia 1
Heel Walking and Toe Walking:
- Tests specific muscle groups and balance 1
3. Balance Tests
Modified Romberg Test:
- Quantified version with timed performance
- Shows excellent test-retest reliability 3
- Age-dependent with lower scores above age 65
Stance with Feet Together:
- Observe for swaying or inability to maintain position 1
4. Quantitative Tests
- Tapping Tests:
- For arms: Patient rapidly taps between two targets
- For legs: Patient rapidly taps foot between two positions
- Both show good correlation with ataxia severity scales 3
Gait Pattern Recognition
Different ataxia types produce characteristic gait patterns:
| Gait Pattern | Characteristics | Likely Cause |
|---|---|---|
| Cerebellar ataxia | Wide-based, irregular stepping, variable step length, lateral veering | Cerebellar lesions, spinocerebellar ataxias |
| Sensory ataxia | High-stepping, stomping gait, worsens with eyes closed | Dorsal column or peripheral nerve disorders |
| Vestibular ataxia | Lurching gait triggered by head rotation, often with vertigo | Vestibular system dysfunction |
Supplementary Assessments
Cranial Nerve Assessment:
- Evaluate nystagmus (common in cerebellar disorders)
- Test for dysarthria using standardized word list 1
Motor Function Assessment:
- Test for hypotonia (common in cerebellar ataxia)
- Assess for pyramidal signs (may indicate ataxic hemiparesis) 4
Common Pitfalls to Avoid
- Failing to differentiate between cerebellar and sensory ataxia
- Not accounting for age-related changes in test performance
- Overlooking accompanying neurological signs that help localize the lesion
- Misinterpreting findings due to patient fatigue or poor cooperation 1
Clinical Pearls
- Ataxia with hemiparesis suggests a cerebral infarct involving the thalamus, pons, corona radiata, or internal capsule 4
- Truncal ataxia and titubation (rhythmic swaying) typically indicate midline cerebellar involvement 5
- Gait velocity decline may be an important objective measure to identify disease progression in adults with progressive ataxias 6
- For treatment planning, focus on strategies that reduce movement complexity by minimizing the number of moving joints or stabilizing against inertial effects 2
By systematically applying these physical examination tests, clinicians can effectively evaluate ataxia, determine its likely etiology, and monitor progression over time.