Neurocognitive predictors of treatment response to randomized treatment in adults with tic disorders

Abstract

Tourette’s disorder (TS) and chronic tic disorder (CTD) are neurodevelopmental disorders characterized by involuntary vocal and motor tics. Consequently, TS/CTD have been conceptualized as disorders of cognitive and motor inhibitory control. However, most neurocognitive studies have found comparable or superior inhibitory capacity among individuals with TS/CTD relative to healthy controls. These findings have led to the hypothesis that individuals with TS/CTD develop increased inhibitory control due to the constant need to inhibit tics. However, the role of cognitive control in TS/CTD is not yet understood, particularly in adults. To examine the role of inhibitory control in TS/CTD, the present study investigated this association by assessing the relationship between inhibitory control and treatment response in a large sample of adults with TS/CTD. As part of a large randomized trial comparing behavior therapy versus supportive psychotherapy for TS/CTD, a battery of tests, including tests of inhibitory control was administered to 122 adults with TS/CTD at baseline. We assessed the association between neuropsychological test performance and change in symptom severity, as well as compared the performance of treatment responders and non-responders as defined by the Clinical Global Impression Scale. Results indicated that change in symptoms, and treatment response were not associated with neuropsychological performance on tests of inhibitory control, intellectual ability, or motor function, regardless of type of treatment. The finding that significant change in symptom severity of TS/CTD patients is not associated with impairment or change in inhibitory control regardless of treatment type suggests that inhibitory control may not be a clinically relevant facet of these disorders in adults.

A Review of the Neuropsychological Dimensions of Tourette Syndrome

“…A recent review reported that studies on this matter failed to reach a conclusive outcome, citing reasons such as comorbidity, patients’ age and control measures to explain discrepancies [ 138 ]. Yet, more recent research with the one of the largest sample to date among neuropsychological studies of TS patients found a fine and gross motor dexterity performance that was one SD below the mean of normative data [ 134 ]. This suggests that prior studies might have lacked the power to detect such impairments in TS patients.…”

“…In adults with TS, most studies found Purdue Pegboard impairments [ 33 , 72 , 132 , 133 , 134 ], but normal performance was also reported [ 107 ]. Importantly, the study of Abramovitch et al [ 134 ] had one of the largest sample among the neuropsychological literature in TS, and reported that patients performed one standard deviation below the norms on the bimanual Purdue Pegboard. Bornstein [ 135 ] found impaired Grooved Pegboard performance for the dominant hand, but not for the non-dominant hand.…”

“…Few studies found no impact of comorbidity on the Purdue Pegboard [ 90 ], the Grooved Pegboard [ 90 , 137 ] and the Finger tapping test [ 137 ]. While performance on the Purdue Pegboard was shown to improve following CBT [ 133 ], a recent study showed that performance on this task was unrelated to symptoms improvement following CBT in a very large sample of adults with TS [ 134 ]. This difference could be explained by the use of different therapies.…”

“…This difference could be explained by the use of different therapies. While Abramovitch et al [ 134 ] used the comprehensive behavioral intervention for tics (CBIT) and psychoeducation and supportive therapy (PST), Lavoie et al [ 133 ] used the cognitive–psychophysiological (CoPs) therapy, which aims to reduce overall motor activation and muscle tension.…”

Investigating Habituation to Premonitory Urges in Behavior Therapy for Tic Disorders

“…This may be seen as indicating that top-down inhibition, manipulated by proxy in this study via the used of reinforcement for tic suppression, led to decreased tic severity in the presence of urges. There are, however, negative findings that contradict the notion that inhibitory control is correlated with improved tic suppression, as a recent study found that improvements in tic severity during CBIT were not associated with performance on a neuropsychological measure of response inhibition (Abramovitch et al, 2017). …”