Replication of Reduced Pattern Electroretinogram Amplitudes in Depression With Improved Recording Parameters

Area of Science:

• Neuroscience
• Ophthalmology
• Psychiatry

Background:

• The retina is increasingly studied in non-ophthalmological research.
• Pattern electroretinogram (PERG) assesses retinal ganglion cell function and has shown reduced contrast gain in depression.
• PERG responses vary with stimulus contrast, check size, and frequency, necessitating optimized recording procedures for psychiatric diagnostics.

Purpose of the Study:

• To evaluate optimized pattern electroretinogram (PERG) recording procedures for major depressive disorder (MDD) diagnostics.
• To investigate the impact of different stimulation frequencies and checkerboard sizes on PERG amplitudes in MDD patients.
• To explore the potential of PERG ratios as an objective biomarker for depression.

Main Methods:

• A pilot study involving 12 patients with major depressive disorder (MDD) and 12 healthy controls.
• PERG amplitudes were recorded using two steady-state pattern reversal frequencies (12.5/18.75 rps) and four checkerboard sizes (0.8°, 1.6°, 3.2°, 16°).
• PERG ratios (0.8°/16°) were calculated, adapting a protocol used for early glaucoma detection.

Main Results:

• MDD patients exhibited smaller PERG amplitudes across all tested parameters, with stimulus-specific reductions.
• The most significant PERG amplitude decline in MDD was observed at higher frequencies and finer patterns.
• Significantly reduced PERG ratios (0.8°/16°) were found in MDD patients at the higher stimulation frequency (18.75 rps).

Conclusions:

• PERG response normalization using ratios shows promise as an objective biomarker for depression.
• This ratio-based approach may facilitate inter-individual assessments of PERG recordings in psychiatric disorders.
• Optimized PERG protocols, including specific check size ratios, could aid in the objective diagnosis of depressive states.