Sensory pathways evaluation in children and adolescents with tic disorder

Background: Tic and Tourette disorders are not just movement disorders. Non-motor elements either sensory or cognitive are frequently associated with the expression of tics, commonly referred to as ‘premonitory urge’. Older children with tic disorder are able to describe their sensory sensitivity, but this may remain undetected and underestimated in toddlers and young children. Although an important element in the pathophysiology of tic disorder, sensory pathways have not been widely evaluated neither in the clinical nor in a research setting. Objective: To elucidate associated sensory symptoms in children presenting with tic disorder. Methods: We studied 81 children and adolescents with tics and Tourette syndrome, (N = 62 children with provisional tic disorder, Ν = 12 children with chronic motor tic disorder, Ν = 7 children with Tourette syndrome), aged 3,5 to 15,5 years. In order to assess their sensory symptoms, all subjects underwent evaluation through the following YGTSS (Yale Global Tic Severity Scale) for the assessment of tic severity, Premonitory Urge for Tics Scale (PUTS) for the assessment of premonitory urge and Sensory Profile (SPQ) for the assessment of sensory disorders. Additionally, sensory pathways were evaluated using sensory evoked potentials (SEPs). Results: A significant positive correlation was found between age and Total YGTSS score (rho = 0.335, p < 0.05), as well as a between age and PUTS (rho = 0.445, p < 0.05) and PUTS and Yale (rho = 0.482, p < 0.05). According the results of regression analysis, we conclude that PUTS can be used as a prediction of Yale with the aid of a specific mathematic formula. Yale = 1.389*PUTS + 4.836 No significant correlation was found in median nerve SEP cortical latencies between patients and age-matched controls. Conclusion: The evaluation of sensory symptoms in children with tic disorders could be of benefit in the design of individualized management and specific interventions and thus should be part of their routine assessment.