Abstract
Purpose :
Patients with prodromal (early) Alzheimer’s Disease (AD) with minimal cognitive impairment have been shown to have abnormalities in retinal ganglion cells (RGCs) as measured by electroretinography (ERG). Herein, we tested the hypothesis that patients with preclinical AD who are asymptomatic, will exhibit a reduction in the Pattern Electroretinogram (PERG) P50 and N95-waves and Photopic Negative Response (PhNR) amplitudes measured by ERG to detect earlier pathology of RGC function.
Methods :
We prospectively enrolled participants aged 60-100 with preclinical AD (15 patients, 30 eyes) and cognitively healthy adults (control; 15 patients, 30 eyes), classified after medical, neuropsychological, ophthalmic and cerebrospinal fluid Ab42/pTau ratio examination. Standard PERG and ISCEV standard full-field ERG were performed in the preclinical stage of AD compared to normal healthy controls. Recorded data were statistically analyzed using Welch’s t-test.
Results :
PERG and PhNR detected RGC dysfunction in preclinical AD. In PERG examination, amplitude reduction in N95-waves (P < 0.04) were observed indicating impairment of RGCs. Mean full-field PhNR amplitudes attenuated significantly in preclinical AD compared to controls (P < 0.03), confirming RGC abnormalities. Scotopic and photopic ISCEV standard full-field ERG showed no significant difference among preclinical AD and controls.
Conclusions :
The present study demonstrated RGC dysfunction in patients with preclinical AD as measured by PERG and PhNR but not ISCEV standard full-field ERG. Our findings suggest that electroretinography may serve as a feasible and non-invasive means of assessing AD prior to the onset of cognitive deficits which may be used in conjunction with other retinal and neurological biomarkers as outcome measures for candidate treatments.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.