Photobiomodulation for Cognitive Dysfunction (Brain Fog) in Post-COVID-19 Condition: A Randomized Sham-Controlled Pilot Trial

Post-COVID-19 condition (PCC) affects millions globally, with cognitive dysfunction (“brain fog”) impairing daily functioning in up to 88% of patients. No effective treatments exist for PCC-related cognitive impairment. We conducted a randomized, double-blind, sham-controlled pilot clinical trial to evaluate the efficacy of home-based photobiomodulation (PBM) using the Vielight Neuro RX Gamma device in 43 adults with PCC. Participants received 8 weeks of daily 20-minute PBM or sham treatment, targeting the default mode network. The primary outcome was change in cognitive performance (Creyos battery) at Day 56. Active PBM showed greater improvement in composite cognitive scores (p=0.088), with significant gains in participants under 45 years (p=0.028). Attention tasks improved consistently across groups. PBM was safe, with high compliance and no serious adverse events. These findings suggest PBM’s potential as a non-invasive intervention for PCC cognitive impairment, warranting larger trials to confirm efficacy.