Development of high frequency vestibulo-ocular responses to active head shaking

Area of Science:

• Neuroscience
• Ophthalmology
• Gerontology

Background:

• The Vestibular-Ocular Reflex (VOR) is crucial for maintaining gaze stability during head movements.
• Traditional VOR testing methods have limitations, particularly at higher frequencies.
• Computer-aided active head shaking offers a promising alternative for comprehensive VOR assessment.

Purpose of the Study:

• To evaluate Vestibular-Ocular Reflex (VOR) gain and phase across different age groups using active head shaking.
• To investigate the impact of aging on high-frequency VOR responses.
• To establish the utility of a novel computer-aided measurement system for VOR analysis.

Main Methods:

• Development of an original measurement system integrating electrooculography (EOG), an angular velocity sensor, and a microcomputer.
• Assessment of VOR gain and phase using transfer function analysis.
• Examination of 40 healthy subjects aged 10 to 75 years during active head shaking at frequencies > 2 Hz.

Main Results:

• VOR gain remained comparable to that of children under 10 years old at frequencies above 2 Hz.
• VOR gain was approximately 1 within 2 Hz, decreasing significantly above 4 Hz.
• Age-related decline in VOR gain was evident at frequencies > 4 Hz, particularly in subjects over 50 years old; no significant phase lag was observed below 5 Hz.

Conclusions:

• Computer-aided active head shaking effectively assesses high-frequency VOR responses.
• Aging impacts VOR gain at frequencies above 4 Hz, becoming noticeable after 50 years of age.
• This method provides valuable insights into age-related changes in vestibular function.