Schedule of Events | Symposia

Gamma Power is a Timescale-Dependent Biomarker for Cognition in Young Adults with Down Syndrome in a Clinical Trial of Transcranial Photobiomodulation

Poster Session A - Saturday, March 29, 2025, 3:00 – 5:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Lauren Sidelinger^1,2 (lsidelinger@mgh.harvard.edu), Maia Gersten^1,2, Puneet Velidi^1,2, Borja Ferreras^1,2, Katelyn Sylvester^1,2, Carlos Lohmann^1,2, Fabio Luchese^1,2, Paolo Cassano^1,2; ¹Massachusetts General Hospital, ²Harvard Medical School

Down syndrome (DS) is an intellectual disability characterized by alterations in brain oscillatory patterns and mitochondrial dysfunction. More specifically, in the gamma band (30Hz-100Hz), individuals with DS, and other neurodegenerative conditions like Alzheimer's disease, have less gamma power compared to age-matched controls. Gamma power has also been correlated with cognitive performance in an elderly healthy population, suggesting that gamma oscillations could make an effective neuromodulation target. The present analyses investigate whether changes in gamma power correlate with changes on neuropsychological test performance for young adults with DS (n=14) and take place in the context of a double-blind sham-controlled clinical trial for transcranial photobiomodulation (t-PBM) using near-infrared (NIR) light. Neuropsychological testing (such as the Kaufman Brief Intelligence Test-II (KBIT-2)) and an EEG were performed at baseline (BL), 6 weeks (6W) immediately following a treatment block, and 12 weeks. These preliminary analyses investigate whether changes in gamma power, either occurring naturally or induced by t-PBM potentially engaging neural oscillations of the gamma frequency band, correlated with changes in cognitive performance between sessions. We found that the KBIT-2 IQ Standard Score performance correlated with low gamma (31Hz-55Hz) power for baseline performance (r=0.63, p=0.022) and that changes in performance between BL and 6W correlated with changes in lower gamma power at these timepoints (r=0.65, p=0.02). However, changes from BL to 12W (r=-0.14, p=0.66) and 6W to 12W (r=-0.07, p=0.82) were insignificant. This raises interesting questions about the reliability and usability of gamma power as an indicator of cognitive performance and change.

Topic Area: EXECUTIVE PROCESSES: Development &aging