Tailored light intervention for sleep and cognition in World Trade Center (WTC) cohort.

World Trade Center rescue and recovery workers and volunteers (WTC RRWV) are vulnerable to circadian rhythm disruption due to stress and environmental exposures during the 9/11 operation, with high rates of cognitive impairment and poor sleep quality. This exploratory pilot study assessed the feasibility and preliminary effect of a 12-week light-based intervention targeting sleep and cognition. Twenty-three WTC RRWV aged ≥50 years with mild cognitive impairment and sleep disturbances completed the intervention. Sleep, cognition, and circadian-effective light exposures were measured pre-and post-intervention using actigraphy, Pittsburgh Sleep Quality Index, cognitive tasks (go/no-go, digit span, Stroop), and a Daysimeter. Results showed significant improvements in sleep quality and cognitive performance. Greater circadian-effective light exposure was positively associated with improved cognitive accuracy. These preliminary observations suggest that light-based interventions may enhance sleep and cognitive function in at-risk populations.