Investigating Circadian Rhythms in Youth With Persistent Tic Disorders

This study examines circadian rhythms and morningness-eveningness preference in youth with Persistent Tic Disorders (PTDs), including Tourette's Disorder (TD); and assesses the effects of wearable short wavelength light therapy on circadian rhythms and tic symptoms.

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.

The clock time at which salivary melatonin concentration reaches a threshold of 4 picograms (pg) per milliliter.

The YGTSS (Leckman et al., 1989) is a clinician-administered measure of tic severity encompassing tic number, frequency, intensity, complexity, and interference. The measure yields independent severity ratings for motor and vocal tics, a combined total tic severity score (0 to 50), and an independent tic-related impairment score (0 to 50).

The CGI-I (Guy, 1976) is a clinician-rated scale that has been used in a number of clinical trials for over 25 years, and in several studies with TD patients. The CGI-I is a clinician-rated measure of global patient improvement relative to baseline based on the clinician's perspective. Scores of Much (2) or Very Much (1) Improved indicate positive treatment response.

The CMEP (Carskadon et al., 1993) is a 10-item measure of diurnal or nocturnal activity preference in recent past weeks. It will be modified to assess symptoms in the past week for the present study. The measure yields a total score ranging from 10 (extreme evening preference) to 42 (extreme morning preference).

The PTQ (Chang et al., 2008) is a parent-reported measure of tic severity assessing both motor and vocal tics present within the past week. Individual tics are rated separately according to frequency and intensity. The measure yields separate scores for motor and vocal tics, in addition to a combined total tic severity score.

Inclusion Criteria: DSM-5 diagnosis of Tourette's Disorder, Persistent Motor Tic Disorder, or Persistent Vocal Tic Disorder Yale Global Tic Severity Scale Score ≥ 14 for Tourette's Disorder or ≥ 10 for Persistent Motor Tic Disorder or Persistent Vocal Tic Disorder fluency in English Exclusion Criteria: Current or lifetime diagnosis of Bipolar Disorder, psychosis, or autism spectrum disorder Suicidality, severe depression or anxiety (i.e., Depression or anxiety diagnosis is more severe than Tourette's Disorder; equivalence in severity is allowed), or substance dependence, present within the past 6 months Current diagnosis of Obstructive Sleep Apnea, Restless leg syndrome, Periodic Limb Movement Disorder, or Narcolepsy Intellectual functioning below the low average range (WASI-II IQ score < 80) Hypnotic medications, or melatonin within 8 weeks of study enrollment Changes in dosage of any psychiatric medications within the past month Behavior therapy for tics within the past 3 months Prior use of light therapy Current pregnancy or travel across > 2 time zones in the past month Medical or neurological condition (e.g., seizure disorder, migraines) that would interfere in the individual's ability to participate in the study

Carskadon MA, Vieira C, Acebo C. Association between puberty and delayed phase preference. Sleep. 1993 Apr;16(3):258-62. doi: 10.1093/sleep/16.3.258.

Chang S, Himle MB, Tucker BTP, Woods DW. Initial psychometric properties of a brief-parent-report instrument for assessing tic severity in children with chronic tic disorders. Child and Family Behavior Therapy 31(3): 181-191, 2009.

Coles ME, Strauss GP. Shedding light on tics. Psychiatry Res. 2015 Feb 28;225(3):743. doi: 10.1016/j.psychres.2014.12.024. Epub 2014 Dec 23. No abstract available.

Guy W. ECDEU assessment manual for psychopharmacology. Rev. Rockville, Md.: National Institute of Mental Health. (DHEW publication no. (ADM) 76-338), 1976.

Leckman JF, Riddle MA, Hardin MT, Ort SI, Swartz KL, Stevenson J, Cohen DJ. The Yale Global Tic Severity Scale: initial testing of a clinician-rated scale of tic severity. J Am Acad Child Adolesc Psychiatry. 1989 Jul;28(4):566-73. doi: 10.1097/00004583-198907000-00015.

Niederhofer H. Bright light therapy may be a therapeutic option for Tourette's syndrome. Acta Neuropsychologica 7(4): 283-285, 2009.