Evaluating Cognitive Function in Primary Open Angle Glaucoma Using Functional Near-Infrared Spectroscopy (fNIRS): A Case Control Study.

PRECIS: This study used fNIRS during a Go/No-Go task to reveal altered prefrontal activation in POAG patients, indicating compensatory cortical recruitment and subtle cognitive dysfunction, highlighting glaucoma's broader neurodegenerative and cognitive impact. PURPOSE: To evaluate cognitive function in individuals with primary open-angle glaucoma (POAG) by assessing prefrontal cortical activity during a behavioral inhibition test (Go/No-Go task) using functional near infrared spectroscopy (fNIRS). PATIENTS: Fifteen patients with mild to moderate POAG and fifteen age and gender matched healthy controls. METHODS: In this pilot case-control study, all participants underwent cognitive assessment using Addenbrooke's Cognitive Examination III (ACE-III), and quality-of-life assessment using EuroQol 5-Dimension 5-Level (EQ-5D-5L) questionnaire. Prefrontal cortical activation patterns were assessed in the prefrontal cortex using a 17-channel fNIRS system during a block-design Go/No-Go task assessing sustained attention and response inhibition. Using statistical parametric mapping (SPM) with general linear model (GLM) analysis, the study observed activation/deactivation in prefrontal cortical regions. RESULTS: Mean age and gender ratio were comparable between the two groups. POAG patients demonstrated significantly lower cognitive scores on ACE-III and reduced health-related quality of life compared to healthy controls (P<0.001). fNIRS demonstrated abnormal prefrontal activation in POAG, with significant hyperactivation during Go versus Rest at channels 8, 13, and 14 (P<0.05), not observed in healthy controls. Conversely, in No-Go vs Rest, healthy controls exhibited significant activation at channels 8, 10, and 15 (P<0.05), absent in POAG. Finally, the Go vs No-Go contrast revealed heightened deactivation in POAG at channel 17 (P<0.05), not observed in healthy controls. CONCLUSIONS: Patients with POAG demonstrated altered and less efficient prefrontal cortical activation patterns during tasks requiring attention and inhibition. These fNIRS based findings suggest early cortical dysfunction in glaucoma.