Functional impairment in Tourette syndrome: parent and child perspectives

Tourette syndrome is a neurodevelopmental condition associated with a number of potential clinical phenotypes and impairment across several domains, making it difficult to delineate the disabilities and determine their differential impact on a patient’s function in order to appropriately direct treatment. Scales used to measure tics in Tourette syndrome are usually geared toward quantifying the motor and vocal tics, but are not as good in measuring the effect of tics on different dimensions of life, the differential effect of tics versus other comorbidities on the patient’s life, and the patient’s view of the disease. Moreover, the perception of the patient’s disease impact on different aspects of life, and the physician’s assessment on disease-generated disability, can often diverge from each other. Traditionally, generic health-related quality of life (QoL) instruments have been used to assess the functional impact of Tourette syndrome and its different components, although a few disease-specific instruments for QoL in Tourette syndrome have been developed and used. Cloes et al. use the Child Tourette Syndrome Impairment Scale to compare QoL in patients with Tourette syndrome and healthy controls. They conclude that the Tourette syndrome parent and child ratings are higher than the healthy controls and correlate with clinicians’ ratings of tic severity. Limitations of the design in this study include the fact that the healthy control data was not obtained from a person-to-person interview, no neurological controls were used, and the parent sample consisted overwhelmingly of mothers. Even though further validation and comparison with other Tourette syndrome-specific QoL scales is needed, this is an important step in further expanding our knowledge of the patients’ and families’ perception of how their health impacts their life, and in developing tools to accurately measure it in order to tailor our treatments more effectively. The usefulness of self-reported instruments to assess function has been questioned in children with Tourette syndrome with concerns of decreased insight, especially in regard to comorbidities. In one study, the impact of tics and comorbid conditions on health-related QoL was assessed from the point of view of the children compared to their parents, with children being more concerned about tics, and parents putting more weight on comorbidities. Similarly, in another study, the children’s self-reported QoL inversely correlated to a measure of tic severity while the parent’s reported QoL weakly correlated with tics, with the caveat that the correlations between parent and child ratings of QoL for children 8 to 11 years were generally higher than those for young people aged 12 to 17 years. The present study by Cloes et al. reproduces these observations, highlighting the fact that children do have insight into their symptoms but their concerns can be different to those of their parents. Tourette syndrome can affect an individual’s physical, psychological, and social well-being. When contemplating treatment, the physician’s role is to weigh in all the manifestations of the disease and the functional impact on the patient’s life. In the case of children, differing perspectives between the patient and the parents can add to the complexity of decision-making. Developing and validating good clinical and research tools to better understand this disparity and direct our outcomes remains an unmet need and the study by Cloes et al. is a step in the right direction.