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Closed-loop caloric, harmonic acceleration and active head rotation tests: norms and reliability
1School of Communicative Disorders, University of Wisconsin, Stevens Point 54481.
Summary
This study evaluated test-retest reliability for bithermal caloric (BC), sinusoidal harmonic acceleration (SHA), and active head rotation (AHR) tests in 20 healthy individuals. SHA and AHR tests demonstrated better reliability than BC, crucial for vestibular function assessment.
Area of Science:
- Vestibular System Physiology
- Neuroscience
- Audiology
Background:
- Accurate assessment of vestibular function is critical for diagnosing balance disorders.
- Standardization and reliability of vestibular testing methods are essential for clinical practice.
- Previous research highlights variability in test-retest data for certain vestibular assessments.
Purpose of the Study:
- To establish norms and evaluate test-retest reliability for bithermal caloric (BC), sinusoidal harmonic acceleration (SHA), and active head rotation (AHR) tests.
- To compare the reliability of different vestibular testing modalities in individuals with normal hearing and balance.
- To identify potential improvements or limitations in current vestibular assessment techniques.
Main Methods:
- Twenty individuals with normal hearing and balance underwent two testing sessions (≥24 hours apart) for BC, SHA, and AHR.
- Bithermal caloric testing utilized a closed-loop irrigator.
- Active head rotation was assessed under three conditions: eyes open (AHR-EO), eyes closed (AHR-EC), and eyes open with a moving target (AHR-FX).
Main Results:
- Bithermal caloric testing requires a 30% unilateral weakness to confidently identify significant inter-ear differences, exhibiting poor test-retest correlations.
- Sinusoidal harmonic acceleration showed generally better test-retest correlations than BC, particularly for phase measures.
- Active head rotation testing revealed high test-retest correlations for AHR-EC, while AHR-EO showed the poorest correlations.
Conclusions:
- Sinusoidal harmonic acceleration and active head rotation (especially AHR-EC) offer superior test-retest reliability compared to bithermal caloric testing for assessing vestibular function.
- The findings suggest that SHA and AHR may be more robust for clinical use due to their higher reliability.
- Variability in BC testing necessitates careful interpretation of inter-ear differences, while AHR-FX shows comparable reliability to previous studies.