Effects of Transcranial Photobiomodulation on Motor Symptoms in Individuals with Parkinson’s Disease – A Pilot Study

• Victoria Lugo, Psychology, University of Delaware

• John Jeka, Kinesiology and Applied Physiology, University of Delaware

Parkinson’s Disease (PD) is the second-most common neurodegenerative disease, with the highest rate of growth. With the loss of dopaminergic neurons within the cortico-striatal network, motor symptoms arise that significantly affect daily living. Currently, there is no known treatment that can slow PD progression. While effective at managing symptoms, PD medications (e.g. levodopa) can result in motor fluctuations and dyskinesia. Deep-brain-stimulation proves effective for some, but is an invasive procedure with risks. Considering these limitations, the potential of transcranial photobiomodulation (tPBM)—a non-invasive and safe form of light therapy—as an additive treatment to reduce symptoms necessitates further exploration. Studies suggest tPBM enhances cerebral metabolism, reduces neuroinflammation, and increases cerebral blood flow. With PD animal models, research shows tPBM to have a neuroprotective effect, reduce oxidative stress, and improve mobility. Clinical trials assessing tPBM on PwP show improvements with gait, speed, and balance. However, tPBM research with human PD subjects is still in the early stages. This study aims to explore the effects of tPBM (laser, 810 nm, 3.5 W) on motor symptoms when applied to the frontal cortex region; stimulating this region may enhance motor planning and executive functioning. Four participants with PD (age 64.25 ± 7.76; 3 male, 1 female) received tPBM via a helmet (NeuroThera, Inc) for 12 minutes, 3 times a week, for 6 weeks. Motor assessments were collected pre- and post-intervention, following overnight withdrawal from PD medications. Preliminary results suggest overall symptom severity was reduced for participants’ more affected side, as average MDS-UPDRS-III scores decreased pre- to post-intervention. Improvements were shown with the upper limb, while lower limb measures showed little change. Results from KinesiaOne, an objective motor assessment system, indicated that rhythmicity of hand movements improved more than speed, likely reflecting tPBM’s stimulation of cortical regions involved with motor timing and coordination. Although these findings suggest a degree of effectiveness of tPBM on PD motor symptomatology, a larger sample size and a placebo group is necessary to attribute these changes to the tPBM intervention.