Memory and executive functions in adults with Gilles de la Tourette syndrome and chronic tic disorder.
(73/312)
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. (+info)
Speeded processing of grammar and tool knowledge in Tourette's syndrome.
(74/312)
Tourette's syndrome (TS) is a developmental disorder characterized by motor and verbal tics. The tics, which are fast and involuntary, result from frontal/basal-ganglia abnormalities that lead to unsuppressed behaviors. Language has not been carefully examined in TS. We tested the processing of two basic aspects of language: idiosyncratic and rule-governed linguistic knowledge. Evidence suggests that idiosyncratic knowledge (e.g., in irregular past tense formation; bring-brought) is stored in a mental lexicon that depends on the temporal-lobe-based declarative memory system that also underlies conceptual knowledge. In contrast, evidence suggests that rule-governed combination (e.g., in regular past tenses; walk+-ed) takes place in a mental grammar that relies on the frontal/basal-ganglia-based procedural memory system, which also underlies motor skills such as how to use a hammer. We found that TS children were significantly faster than typically developing control children in producing rule-governed past tenses (slip-slipped, plim-plimmed, bring-bringed) but not irregular and other unpredictable past tenses (bring-brought, splim-splam). They were also faster than controls in naming pictures of manipulated (hammer) but not non-manipulated (elephant) items. These data were not explained by a wide range of potentially confounding subject- and item-level factors. The results suggest that the processing of procedurally based knowledge, both of grammar and of manipulated objects, is particularly speeded in TS. The frontal/basal-ganglia abnormalities may thus lead not only to tics, but also to a wider range of rapid behaviors, including the cognitive processing of rule-governed forms in language and other types of procedural knowledge. (+info)
A measure of functional impairment in youth with Tourette's syndrome.
(75/312)
OBJECTIVE: Tourette's Syndrome (TS) during childhood is linked to varied behavioral and psychological difficulties and functional impairment. The current study was undertaken to examine both tic-related impairment and impairment from other psychological problems in 59 youth (mean age 11.4 years, 69% male) with TS. METHODS: Caretakers completed a checklist about the impact of tics and other psychological difficulties on family, school, and social functioning. In addition, a clinician administered a measure of tic severity to families. RESULTS: Over half of the sample reported one significant problem area due to the presence of tics, with over a third reporting two or more problem areas. Problems were heterogeneous in nature, with no report of a particular problem area in more than 25% of the children. The rate of nontic-related impairment was very high, with 70% of parents reporting at least one problem area. CONCLUSIONS: Treating both tic and nontic-related impairments concurrently may improve functioning more so than treating the symptoms separately. (+info)
A developmental fMRI study of self-regulatory control in Tourette's syndrome.
(76/312)
OBJECTIVE: Disturbances in the maturation of neural systems that mediate self-regulatory processes may contribute to the development of Tourette's syndrome by releasing motor and vocal tics from regulatory control. The purpose of this study was to examine the age correlates of functional activity in neural circuits that subserve self-regulatory control in children and adults with Tourette's syndrome. METHOD: The participants were 136 children and adults, which included 66 Tourette's syndrome patients and 70 healthy comparison subjects. During performance of the Stroop interference task, the authors compared the functional magnetic resonance imaging (fMRI) blood-oxygen-level dependent response in patients with Tourette's syndrome with that of healthy comparison subjects. General linear modeling of Stroop-related activations was used to compare the differential effects of age and behavioral performance on changes in self-regulatory control between the two diagnostic groups. RESULTS: Although the correlations of age with behavioral performance on the Stroop task were similar between patients with Tourette's syndrome and healthy comparison subjects, the two groups differed significantly in their correlations of age with the magnitude of regional brain activation during the task. Interactions of age with diagnosis were detected in the ventral prefrontal (Brodmann's areas 10 and 24) and posterior cingulate cortices (Brodmann's area 31), and post hoc analyses indicated that subjects with Tourette's syndrome deactivated these regions less with advancing age. Greater activation of bilateral frontostriatal regions (Brodmann's areas 9/46, 45/46; lenticular nucleus; and thalamus) accompanied poorer performance in the patient group, which-in the presence of normal behavioral performance on the Stroop task-suggests that greater activation of the frontostriatal systems helps to maintain task performance in individuals with Tourette's syndrome. CONCLUSIONS: Normative developmental correlates of activity in frontostriatal circuits that subserve self-regulatory control are disturbed in persons with Tourette's syndrome. These aberrant developmental correlates are likely a consequence of greater anatomical and functional disturbances in these circuits in adults with Tourette's syndrome, which leads to impaired regulation of tic behaviors. Reduced default-mode processing in ventral prefrontal and posterior cingulate cortices in adults with Tourette's syndrome suggests the presence of greater difficulty in engaging mental processes that become active when freed from the demands of more challenging cognitive tasks. However, individuals with Tourette's syndrome appear to co-opt normal developmental processes in circuits that subserve age-related improvement in self-regulatory control while presumably struggling to maintain adequate task performance. (+info)
Atomoxetine treatment of ADHD in Tourette syndrome: reduction in motor cortex inhibition correlates with clinical improvement.
(77/312)
OBJECTIVE: In children with attention deficit hyperactivity disorder (ADHD), clinical responses to the selective norepinephrine reuptake inhibitor atomoxetine (ATX) vary. We sought to determine in children with Tourette Syndrome (TS) whether clinical responses correlate with changes in short interval cortical inhibition (SICI). METHODS: Fourteen children, ages 8-16, with ADHD and TS were treated open-label with ATX for one month. ADHD rating scale scores and SICI, measured with paired-pulse transcranial magnetic stimulation (pTMS), were assessed blindly and independently at treatment onset and one month later. RESULTS: Eleven children, mean ADHD rating scale scores 31.8 (SD 8.2) at onset, completed the study. After one month, ADHDRS changes ranged from an increase of 4 points to a decrease (improvement) of 24 points (mean change -9.6, SD 9.1). The changes in ADHDRS scores correlated with reduction in SICI (r=.74, p=.010). CONCLUSIONS: In children with TS, one month of atomoxetine treatment appears to induce correlated improvements in ADHD and, paradoxically, further reductions in cortical inhibition. SIGNIFICANCE: PTMS-evoked SICI in ADHD with TS may be a biomarker of both deficiency and compensatory changes within cortical interneuronal systems. Effective atomoxetine treatment may augment compensatory processes and thereby reduce SICI. (+info)
Gilles de la Tourette's syndrome associated with head injury: a case report.
(78/312)
A case of Gilles de la Tourette's syndrome in a Kuwaiti woman is described, and the possibility of antecedent head injury as the organic etiological factor is discussed. (+info)
Neuroimaging of tic disorders with co-existing attention-deficit/hyperactivity disorder.
(79/312)
BACKGROUND: Tourette syndrome (TS) and Attention-Deficit/Hyperactivity Disorder (ADHD) are common and debilitating neuropsychiatric illnesses that typically onset in the preschool years. Recently, both conditions have been subject to neuroimaging studies, with the aim of understanding their underlying neurobiological correlates. OBJECTIVE: The relation of TS and ADHD is discussed against the background of findings from previous Magnetic Resonance Imaging (MRI) studies. METHODS: We review the designs and major findings of previous studies that have examined TS with comorbid ADHD, and we briefly contrast these findings with those in ADHD without comorbid tic disorders. RESULTS: The frequent comorbidity of TS and ADHD may reflect a common underlying neurobiological substrate, and studies confirm the hypothesized involvement of fronto-striatal circuits in both TS and ADHD. However, poor inhibitory control and volumetric reductions in fronto-striatal circuits appear to be core features of ADHD, whereas reduced volumes of the caudate nucleus, together with activation and hypertrophy of prefrontal regions that likely help to suppress tics, seem to be core features of TS. CONCLUSION: The etiological relationship between TS and ADHD must be clarified further with cross-sectional and, if possible, longitudinal imaging studies that examine samples of substantial size, including subgroups with pure TS and ADHD, as well as with comorbid conditions. (+info)
Tourette's syndrome: clinical features, pathophysiology, and therapeutic approaches.
(80/312)
Tourette's syndrome (TS) is a disorder characterized by simple and complex motor tics, vocal tics, and frequently obsessive-compulsive symptoms. Its onset occurs before the age of 21. Typically, TS shows a waxing and waning course, but a chronification of the tics, even during later life, is often observed. TS mainly occurs in boys, and shows genetic heritability with differing penetrance. The pathological mechanism is still unclear Neuroanatomical and neuroimaging studies, as well as effective treatment using antipsychotics, suggest that a disturbance of the dopaminergic system in the basal ganglia plays an important role in the pathogenesis of TS. Several possibly causative mechanisms of the disturbed dopaminergic neurotransmission are discussed, with the main emphasis on the-infection-triggered-inflammatory immune process. Extrapyramidal movement disorders are known to occur as a symptom of poststreptococcal disease, such as in Sydenham's chorea. Cases of childhood TS are proposed to be caused by such a poststreptococcal mechanism, being part of a spectrum of childhood neurobehavioral disorders termed pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS). The overlap between TS and PANDAS is discussed, and a critical view of the PANDAS concept is presented. The therapeutic implications of the different pathological mechanisms are described, taking into consideration not only the acute or chronic natures of different infections, but also an autoimmune process. Moreover, therapeutic strategies using typical and atypical antipsychotics, and also experimental therapies such as repetitive transcranial magnetic stimulation and deep brain stimulation, are critically discussed. (+info)