Transcranial Photobiomodulation for autism spectrum disorder: Prospective open-label case series across age groups

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by deficits in social communication, restricted and repetitive behaviors, and frequently co-occurring symptoms such as impulsivity and attention deficits. Emerging non-invasive neuromodulatory approaches, such as transcranial photobiomodulation (tPBM), show promise in addressing underlying dysfunctions implicated in ASD. This prospective open-label case series aimed to explore daily tPBM targeting the right prefrontal cortex (PFC) in individuals with ASD across age groups, and to report exploratory pre-post changes in self-/caregiver-reported measures and behavioral tasks. Eight participants (ages 6–38 years; 2 females, 6 males) with varying ASD severity completed daily 10-minute tPBM sessions (1064 nm; 100 mW/cm²; 60 J/cm²) for eight weeks. The primary outcome was the Autism Spectrum Quotient (AQ). Secondary outcomes were Continuous Performance Task (CPT), weekly behavioral check-ins, and health questionnaires assessing sleep, diet, and gastrointestinal function. Seven participants demonstrated reductions in AQ scores, particularly within the attention to detail, imagination, and communication subscales. CPT data indicated improved sustained attention and reduced impulsivity in participants who completed the task. Weekly check-ins revealed improved emotional regulation, focus, and sleep quality. Five participants reported improvements in stool consistency and dietary variety. Adverse effects were minimal, limited to brief nightmares. tPBM was safe and tolerable and associated with cognitive, behavioral, and physiological improvements in ASD. These changes potentially involve enhanced mitochondrial efficiency, cerebral blood flow, and reduced neuroinflammation. Future studies should aim for larger sample sizes, more diverse populations, and stronger experimental controls to confirm these findings.