Changes in vestibulo-ocular reflex of elderly people

Area of Science:

• Gerontology
• Neuroscience
• Otolaryngology

Background:

• Dizziness is a prevalent symptom in the elderly population.
• Previous studies using the head autorotation test (HART) indicated no significant vestibulo-ocular reflex (VOR) disturbances in healthy elderly individuals.
• Vestibular system function, crucial for balance, can decline with age.

Purpose of the Study:

• To evaluate vestibulo-ocular reflex (VOR) function in elderly volunteers using a recently developed head autorotation test (HART).
• To identify age-related changes in VOR gain and phase across different frequencies.
• To correlate VOR abnormalities with the prevalence of dizziness and falls in the elderly.

Main Methods:

• Utilized a newly developed head autorotation test (HART) to assess VOR in 14 elderly volunteers without otoneurological conditions or sedative use.
• Measured VOR gain and phase across five frequency bands (0.5 to 5 Hz).
• Compared elderly subject data with normative control values.

Main Results:

• Elderly subjects exhibited significantly increased VOR gain (1.11-1.27) at higher frequencies (3-5 Hz) compared to controls.
• A significant phase lead (7-8 degrees) was observed in the 2 Hz and 4 Hz bands in the elderly.
• High-frequency head movements were limited in 50% (3 Hz) and 36% (4 Hz) of elderly participants, versus 100% and 95% in controls, respectively.
• Individual HART results were abnormal in 86% of elderly participants, indicating inaccurate high-frequency VOR magnitude and timing.

Conclusions:

• The high-frequency vestibulo-ocular reflex (VOR) is significantly impaired in magnitude and timing in elderly individuals.
• A majority of elderly subjects struggle to generate rapid head movements, contributing to VOR inaccuracies.
• These VOR deficits likely contribute to the high incidence of dizziness and falls observed in the aging population.