Investigating Circadian Rhythms in Youth With Persistent Tic Disorders

Many individuals with Persistent Tic Disorders (PTDs), including Tourette's Disorder (TD) fail to significantly benefit from existing tic treatments. Case studies have shown morning exposure to light therapy, known to advance circadian phase is associated with modest to large tic reductions (Coles \& Strauss, 2013; Niederhofer, 2003) suggesting the presence of circadian abnormalities (i.e., phase delay) in select individuals with PTDs. The present project assesses circadian phase and morningness-eveningness preference in youth with Persistent Tic Disorders (PTDs), including Tourette's Disorder (TD), and examines whether morning use of wearable short wavelength light therapy is associated with shifts in circadian rhythms and reductions in tic severity. Study participation will take place over a three-week period. Clinician-rated tic interview and rating scales of morningness-eveningness preference, sleep, tic, and other symptoms will be completed during an initial screening assessment. Participants will then monitor sleep at home using an actigraph for one week and return for a baseline clinical assessment of tic severity and evening assessment of internal melatonin levels involving saliva sampling every 30 minutes for 6.5 hours in a dimly lit room. Next, participants will complete an abbreviated course (i.e., two weeks) of morning light therapy using wearable short wavelength (i.e., blue-green) light-emitting glasses while continuing to monitor sleep using the actigraph. Following this two-week period participants will return for a final assessment of tic severity and internal melatonin levels.