A longitudinal study of oculomotor function in normal older people

Area of Science:

• Gerontology
• Neuroscience
• Ophthalmology

Background:

• Previous cross-sectional studies indicate age-related declines in oculomotor function.
• No longitudinal studies have previously tracked oculomotor changes in the same older individuals over time.

Purpose of the Study:

• To longitudinally assess changes in various oculomotor functions in healthy older adults.
• To investigate the relationship between oculomotor function decline and gait/balance performance over time.

Main Methods:

• Longitudinal study of 53 healthy subjects (over 75 years) with at least 9 yearly evaluations.
• Measured saccade peak velocity, saccade delay time, smooth pursuit, optokinetic nystagmus (OKN), visual-vestibular-ocular-reflex (VVOR), fixation suppression of the vestibulo-ocular reflex (VOR-fix), and vestibulo-ocular reflex (VOR).
• Included yearly gait and balance assessments (Tinetti score), medical history, mini-mental status, and visual acuity.

Main Results:

• Smooth pursuit gain and saccade peak velocity remained stable over the study duration.
• Significant declines were observed in OKN, VVOR, and VOR.
• Decline in OKN, VVOR, and VOR correlated significantly with decreased gait and balance scores, even after controlling for age.

Conclusions:

• In healthy aging, smooth pursuit and saccade peak velocity are maintained, while OKN, VVOR, and VOR functions decline.
• The correlation between declining oculomotor and gait/balance measures suggests a common underlying aging mechanism affecting both systems.