Memory and executive functions in adults with Gilles de la Tourette syndrome and chronic tic disorder

Abstract

Introduction: The main aim of the current study was to assess whether adults with either Tourette syndrome (TS) or chronic tic disorder (CTD) show a similar neuropsychological profile. Neuropsychological investigations of tic disorders have been mostly focused on children, mainly because symptoms peak during that period. Little has been carried out on adults, even if a significant proportion of the tic population experience moderate or marked levels of tic frequency throughout adulthood. Still, it is not clear whether neuropsychological performances are affected to the same degree in adults with TS and CTD.

Method: Patients diagnosed with TS were compared with a CTD group and a control group free of psychiatric or neurological diagnosis, comparable in terms of age, gender, and intelligence. All participants completed two tests of memory (Rey-Osterreich Complex Figure, California Verbal Learning Test), one test of motor dexterity (Purdue pegboard), and four tasks of executive function (Stroop, Color Trail Test, Tower of London, Wisconsin Card Sorting Test).

Results: TS and CTD patients showed nonverbal memory impairments while verbal memory and executive functioning remained intact. Results also indicated that nonverbal memory performances decrease as a function of tic severity.

Conclusion: Both TS and CTD patients present a specific nonverbal deficit whilst the executive and motor functions are relatively intact. The two tic disorder subgroups might be part of a spectrum implicating mainly nonverbal memory.