The pattern electroretinogram by skin electrodes: effect of spatial frequency and age

Area of Science:

• Ophthalmology
• Neuroscience
• Vision Science

Background:

• The aging process can affect visual function, including the ability to perceive spatial details.
• Pattern electroretinograms (PERG) are a valuable tool for assessing the function of the inner retina and optic nerve.

Purpose of the Study:

• To investigate age-related differences in steady-state pattern electroretinograms (ssPERG) using sinusoidal gratings.
• To quantify changes in the second harmonic amplitude and phase across various spatial frequencies in older versus younger adults.

Main Methods:

• Recorded steady-state (8 Hz) PERGs in response to sinusoidal gratings using skin electrodes.
• Enrolled 18 healthy older adults (mean age 62.7 years) and 22 healthy young adults (mean age 27 years).
• Ensured all participants had corrected visual acuity of 1.0 or better and no ocular pathology.

Main Results:

• Young subjects exhibited spatially tuned second harmonic amplitudes, peaking around 1.7 cycles per degree (c/deg).
• Older subjects showed significantly reduced ssPERG amplitudes across all tested spatial frequencies (P < 0.05).
• The reduction in amplitude was more pronounced at intermediate spatial frequencies in older adults, leading to shallower tuning (P < 0.01). Response phase did not differ significantly between groups.

Conclusions:

• Aging is associated with a significant reduction in the amplitude of steady-state PERG responses to sinusoidal gratings.
• The diminished response in older adults, particularly at intermediate spatial frequencies, suggests age-related alterations in visual pathway function.
• While amplitude is affected, the phase response remains relatively preserved, indicating specific functional changes with age.