Systematic review of severity scales and screening instruments for tics: Critique and recommendations

Background: Several clinician, informant, and self-report instruments for tics and associated phenomena have been developed that differ in construct, comprehensiveness, and ease of administration. Objective: A Movement Disorders Society subcommittee aimed to rate psychometric quality of severity and screening instruments for tics and related sensory phenomena. Methods: Following the methodology adopted by previous Movement Disorders Society subcommittee papers, a review of severity and screening instruments for tics was completed, applying a classification as “recommended,” “suggested,” or “listed” to each instrument. Results: A total of 5 severity scales (Yale Global Tic Severity Scale, Tourette Syndrome Clinical Global Impression, Tourette's Disorder Scale, Shapiro Tourette syndrome Severity Scale, Premonitory Urges for Tics Scale) were “recommended,” and 6 (Rush Video-Based Tic Rating Scale, Motor tic, Obsessions and compulsions, Vocal tic Evaluation Survey, Tourette Syndrome Global Scale, Global Tic Rating Scale, Parent Tic Questionnaire, Tourette Syndrome Symptom List) were “suggested.” A total of 2 screening instruments (Motor tic, Obsession and compulsions, Vocal tic Evaluation Survey and Autism-Tics, Attention Deficit/Hyperactivity Disorder and Other Comorbidities Inventory) were “recommended,” whereas 2 others (Apter 4-questions screening and Proxy Report Questionnaire for Parents and Teachers) were “suggested.”. Conclusions: Our review does not support the need for developing new tic severity or screening instruments. Potential objectives of future research include developing a rating instrument targeting the full spectrum of tic-related abnormal behaviors, assessing/screening malignant forms of tic disorders, and developing patient-reported outcome measures.