Dopamine transporter density of the basal ganglia assessed with [123I]IPT SPECT in drug-naive children with Tourette's disorder

There is evidence that abnormalities in the dopaminergic system involving the dopamine transporter (DAT) are involved in the pathophysiology of Tourette's disorder (TD) from previous studies using [(123)I]2beta-carbomethoxy-3-(4-iodophenyl)tropane ([(123)I]beta-CIT) and single photon emission tomography (SPECT). However, because those studies were performed in medicated adult patients with TD, we decided to compare DAT densities in nine drug-naive children with TD and eight normal children. The children with TD did not suffer from associated psychiatric problems such as obsessive-compulsive symptoms, attention deficit hyperactivity disorder, anxiety, depression and developmental difficulties. We performed brain SPECT 2 h after the intravenous administration of I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl)tropane ([(123)I]IPT) and carried out both quantitative and qualitative analyses using the obtained SPECT data, which were reconstructed for the assessment of the specific/non-specific DAT binding ratio in the basal ganglia. We then investigated the correlation between the severity of tics in children with TD assessed with the Yale Global Tic Severity Scale (YGTSS) and the specific/non-specific DAT binding ratio of the basal ganglia. Drug-naive children with TD showed a significantly increased specific/non-specific DAT binding ratio in the basal ganglia compared with normal children that did not correlate significantly with the severity of tics. Our results with drug-naive children with TD between the ages of 6 and 12 may help to clarify previous findings concerning DAT binding in adult patients with TD and suggest that DAT densities may be associated directly with the pathophysiology of TD, regardless of disease progress or drug effect.

Association of cortical disinhibition with tic, ADHD, and OCD severity in Tourette syndrome

Hyperkinetic disorders may involve excess excitatory output from thalamus to cerebral cortex. Case-control, neurophysiological studies in persons with Tourette Syndrome (TS), Attention Deficit Hyperactivity Disorder (ADHD), and Obsessive-Compulsive Disorder (OCD) support this model. To compare the strength of association between motor cortex inhibition and tic, ADHD, and OCD severity in TS, we used transcranial magnetic stimulation to measure motor cortex inhibition in 36 children and adults with TS. Current symptom severity was assessed with standard clinical rating scales and compared with neurophysiological measures using correlational and multivariate regression analyses. Severity of ADHD symptoms and motor tics were associated significantly and independently with short interval intracortical inhibition (SICI) (r(2) = 0.50; F[2,27] = 13.7; P < 0.001), particularly in subjects not taking neuroleptics (r(2) = 0.68; F[2,17] = 17.8; P < 0.0001). The correlation of cortical disinhibition was greater with ADHD symptoms severity (r = 0.53; P = 0.003) than with tic severity (r = 0.42; P = 0.02), suggesting that in TS, the association between SICI and ADHD symptoms may be more consistent or direct than the association between SICI and tics.

Phenomenology of tics and natural history of tic disorders

Tic symptoms, the hallmark of Tourette's syndrome (TS), may simply be fragments of innate behavior. As such, the sensory urges that precede tics may illuminate some of the normal internal cues that are intimately involved in the assembly of behavioral sequences. The occurrence of tics in time appears to have fractal characteristics that may help to explain the waxing and waning course of tic disorders. Longitudinal studies are currently underway that should permit a close examination of the natural fluctuations in tic severity using valid and reliable clinician-rated scales of tic severity. The natural history of tics typically shows a marked decline during the course of adolescence. However, TS can also be associated with social, emotional, and academic difficulties in early adulthood. Comorbid attention deficit/hyperactivity disorder and obsessive-compulsive disorder are likely to influence the long-term adaptive outcomes of individuals with TS. Future progress may also be expected as endophenotypes, and possibly genetic markers, are identified that are associated with specific comorbid conditions and etiologically distinct forms of TS.

Clinical characteristics of adult patients with tics and/or Tourette's syndrome

OBJECTIVE

This study was conducted to describe the natural course of tic disorders over a long period of time in Japanese adults patients with Tourette's syndrome (TS) in terms of symptomatology.

METHODS

An extensive literature on TS cases was reviewed selectively and 31 TS patients (mean age: 31.4 years; sex: 28 males and 3 females) at our outpatient clinic were examined. The mean follow-up period of the patients was 7.6 years (SD: 8.1; 0 to 26). All the data available for this study, including medical charts, were examined systematically by two experienced child psychiatrists.

RESULTS

The adult patients with tic disorders could be classified into the four groups: group A - tics only, group B - tics + comorbidities, group C - comorbidities only and group D - sub-clinical (remission) cases. Our 31 subjects consisted of 10 patients (32.3%) for group A, 14 (45.2%) for group B, 7 (22.6%) for group C, and 0 for group D.

CONCLUSIONS

Further investigation into the natural course and clinical characteristics of adult TS needs to be done in order to acquire a better understanding of the broad spectrum of TS and to make improvements to the treatment for this illness.

Abnormalities of voluntary saccades in Gilles de la Tourette's syndrome: pathophysiological consideration

Gilles de la Tourette's syndrome (TS) is a neurobehavioral disorder. Although the etiology and the pathophysiology of TS are still unknown, the involvement of the basal ganglia has long been postulated. On the other hand, saccadic eye movement was shown to be a useful measure to assess order and disorder of the function of the basal ganglia. To investigate the dysfunction of the basal ganglia of TS, we examined voluntary saccades in children with TS in comparison with the saccades in age-matched control children. Two kinds of saccades, visually-guided saccades (VGS) and memory-guided (MGS) saccades were evaluated. During the MGS, distracted saccades (DS), which indicate the distractibility, were examined. The results revealed the abnormalities in the parameters of the MGS, i.e. longer latencies and hypometric amplitudes, and decrease in the frequency of MGS. Whereas, the frequency of DS, the saccade to the predicted cue was significantly lower in younger patients (6-<9-years) than normal, but it was higher in the older TS children (9-<12-years). In addition, some of the patients showed large involuntary saccades, usually associated with eye blinks, during the task performance. These results suggest that in TS the basal ganglia fails to disinhibit the saccade neuron in the superior colliculus with the input of the frontal eye field to the striatum, and later allow the neurons to evoke non-goal directed saccades. In reference to abnormal saccades in other basal ganglia disorders with dopamine deficiency and to animal experiments with MPTP monkeys, these findings postulate primary hypodopaminergic state followed by upward regulation of dopamine receptors later in TS.

Pathophysiology of Tourette's syndrome: striatal pathways revisited

Stereotypic behaviors and thoughts are manifested in a range of neuropsychiatric disorders including Tourette's syndrome. To understand and to treat these pathologic stereotypies it is important to establish the molecular, pharmacological and systems-level alterations in brain circuits that accompany such behaviors. We review here experiments performed in rodents and primates that focus on neural concomitants of stereotypies induced by dopaminergic treatments. These studies emphasize the functional importance of the compartmental organization of the striatum and raise the possibility that differential activation of striosomes is related to the severity of the expressed stereotypies and sensitized responses.

Neurobiology of Tourette's syndrome: concepts of neuroanatomic localization and neurochemical abnormalities

Despite a preponderance of evidence suggesting an organic rather than psychogenic origin for Tourette syndrome, the precise neurobiological abnormality remains speculative. Neuroanatomically, there is expanding confirmation that cortico-striato-thalamo-cortical pathways represent the site of origin for tics and accompanying neuropsychiatric problems. Pathophysiological hypothesis are generally defined based on involvement of (1) a specific anatomical site (striato-thalamic circuits, striatal compartments), (2) physiologic abnormality (excess thalamic excitation, impaired intracortical inhibition), or (3) involvement of a specific neurotransmitter or synaptic component. This review provides information essential for understanding current and future proposals pertaining to the neurobiology of this intriguing disorder.

Neurophysiology of Tourette's syndrome: pathophysiological considerations

At present the neurophysiology of Tourette's syndrome (TS) has been investigated largely from two perspectives; one for evaluation of the dysfunction of the cerebral cortex and the other for clarification of the neuronal mechanisms that underlie tics and related symptoms. For the former the following examinations have been conducted: quantitative analyses of scalp electroencephalography (EEG), premovement EEG potentials, contingent negative variation, transcranial magnetic stimulation, and neuroimaging studies, including echo-planar images and positron emission tomography scans. These explorations have revealed the likely involvement of the subcortical and the cortical structures, particularly of the basal ganglia, in the pathophysiology of TS. For the latter, surface electromyography, evoked potentials, saccadic eye movements, and polysomnographies have been performed, and again have suggested a dysfunction of the basal ganglia and the brainstem neurons in TS patients. These neurophysiological studies suggest dysfunction of both motor and non-motor basal ganglia-thalamocortical circuitries in TS patients, which is hypothesized to be caused by hypofunction of the dopamine (DA) neurons associated with DA receptor supersensitivity, a well as hypofunction of the serotonergic neurons of the brainstem. Polysomnographical examination suggests that the dysfunction of the nigrostriatal (NS)-DA neurons is not a progressive process, but that the dysfunction is closely associated with an early occurrence of the developmental decrement of the activities of the NS-DA system to mature in a normal fashion. The associated DA receptor supersensitivity is assumed to be a consequence of this developmental abnormality and not due to denervation supersensitivity.

Does an imbalance between the dorsal and ventral striatopallidal systems play a role in Tourette's syndrome? A neuronal circuit approach

Tourette's syndrome is characterized by simple, involuntary muscle contractions and/or more complex movements or stereotyped behaviors, including vocalizations. There are strong indications that the basal ganglia play an important role in the pathophysiology of Tourette's syndrome. The present account reviews the functional anatomy of the basal ganglia, with an emphasis on the prefrontal cortex-ventral striatopallidal system. Different parts of the basal ganglia and thalamocortical system, with a focus on the premotor and prefrontal cortices, are connected with each other via parallel, functionally segregated basal ganglia-thalamocortical systems. These parallel circuits, representing sensorimotor, cognitive and emotional-motivational behavioral processes, are connected with each other through specific pathways that serve to integrate these various functions. In the context of the discussion on the pathophysiological mechanisms that lead to the expression of tics, emphasis is placed on the pathways that lead from the ventral striatum via the dopaminergic substantia nigra to the dorsal striatum. The dorsal striatum is crucial for habit formation. A conclusion of this overview of the anatomical organization of the basal ganglia is that via dopaminergic pathways limbic-relation information can influence the expression of (fragments of) motor and behavioral repertoires. Whether such mechanisms indeed play a role in the expression of tics in Tourette's syndrome remains to be established.

Neurology of Tourette's syndrome (TS) TS as a developmental dopamine disorder: a hypothesis

The favorable effect of dopamine (DA) depletors or DA receptor blockers suggested the state of increased transmission of DA system as the pathophysiology of Tourette's syndrome (TS). We have analysed the neurological signs of TS and evaluated the role of levodopa on the symptoms of TS. The data were compared with age-matched patients with Hereditary Progressive Dystonia (HPD) with marked diurnal fluctuation. Neurological examination of 81 drug naive TS patients revealed the clumsiness of rapid alternating pronation-supination movements of the arms and induced rigidity in the contralateral arm, which responded to the oral levodopa, and suggested hypofunction of the nigrostriatal (NS)-DA system. Postural asymmetry or scoliosis and abnormal tilting response suggested the asymmetric involvement of DA. The rotation to the side of less affected DA neuron on stepping with closed eyes suggested DA receptor supersensitivity. The favourable effects of a small dose of levodopa on these signs suggest the existence of DA receptor supersensitivity, because a small dose of levodopa is considered to alleviate the supersensitized DA receptors.

Pilot study of effect of emotional stimuli on tic severity in children with Tourette's syndrome

To assess objectively the effects of emotional stimuli on the severity of tics and to determine if such effects were mediated by the autonomic nervous system, we carried out videotape ratings of tics and electrophysiological monitoring of heart beat and respiration on 4 children with Tourette's syndrome while they were watching a movie known to elicit emotional responses relevant to normal childhood events. Measured tic severity was highest during periods associated with anticipation, resolution of emotional changes, and lower concentration, lowest during periods of anger and happiness, and intermediate during periods of sadness and fear. Tic severity did not correlate with heart or respiratory rate. Thus, tics seem influenced differentially by various emotional states, but this effect does not seem to be autonomically mediated.

Objective assessments of longitudinal outcome in Gilles de la Tourette's syndrome

OBJECTIVE

To define the long-term outcome in Gilles de la Tourette syndrome (GTS) using objective rating measures.

BACKGROUND

Previous historical studies suggest spontaneous improvement of tic symptoms after adolescence, but objective longitudinal data are limited.

METHODS

The authors reviewed all videotapes in their database (1978 through 1991) of children with GTS (ages 8 to 14) who were seen in their tertiary care movement disorder center and underwent a standardized 5-minute filming protocol (n = 56). Through multiple contact methods, they successfully located 36 of these patients, who are now adults (age >20 years), and recruited 31 (28 men and 3 women) to volunteer for a second videotape and in-person assessment. A blinded rater evaluated the 62 tapes and rated five tic domains: body areas involved, motor and phonic tic frequency, and motor and phonic tic severity. Using standardized GTS videotape rating scale and Wilcoxon signed-rank tests with Bonferroni correction for multiple comparisons, the authors compared the two videotapes for each tic domain as well as the composite tic disability score.

RESULTS

Ninety percent of adult patients still had tics. Adult patients who considered themselves tic-free were often inaccurate in their self-assessment: 50% had objective evidence of tics. Mean objective tic disability diminished in comparison to childhood (mean composite tic disability score childhood 9.58 vs adulthood 7.52, p = 0.014). All domains improved by adulthood, and significant improvements occurred in motor tic severity (p = 0.008). The improvements in tic disability did not relate to medication use, as only 13% of adults received medications for tics, compared with 81% of children.

CONCLUSIONS

In GTS syndrome, tics objectively improve over time but most adults have persistent tics.

[Control of inner speech and Gilles de la Tourette's syndrome]

Inner speech is the little voice in the head which comments on everyday life activities. To some aspect, trouble in monitoring the inner speech has been regarded as relevant in auditory hallucinations in psychosis. Another disorder that may involve inner speech is the difficulty inhibiting its vocal utterance (the so-called verbal impulsion ). Verbal impulsion is a classic feature of Gilles de la Tourette's syndrome, during which patients complain of difficulties inhibiting socially undesirable behaviors, especially vocalization (i.e. coprolalia). In a previous paper, we reported on a patient with frontotemporal dementia, whose pathology was revealed by a difficulty inhibiting the verbal utterance of reading (inability to read silently). Later in the course of the disorder, the patient exhibited a severe frontal lobe syndrome with compulsive activities and coprolalia. Externally triggered inner speech has been proposed by the author to be represented by silent reading. In this setting, loss of silent reading can be regarded as the equivalent of a loss of control of the verbal utterance of the inner speech.

CASES REPORT

In the present paper, a loss of control of inner speech is suggested as partly involved in two cases of Gilles de la Tourette's syndrome with coprolalia. Two adult patients with a diagnosis of Gilles de la Tourette's syndrome since age 7 and 10, respectively, have been asked to comment on their present or previous abilities to read silently. The first case never silent read as a child while the second case read silently but had a tendency to move his lips.

DISCUSSION

The frequency of observed difficulties in silent reading is likely to be a function of the age at which the subject is asked about such difficulties. Nevertheless, theoretical arguments are presented in this part of the paper which suggest that silent reading, considered as a way to challenge the control of inner speech, has been variably impaired at different stages of the disease. The author speculates that the key role of prefrontal cortex, especially the orbito-frontal areas, in the inhibitory control of current behavior, can be responsible for the deficit in the control of inner speech. In this setting, recent functional brain imaging performed in patients with Gilles de la Tourette's syndrome showed a striking deficit in the activation of these areas during tics. It would be of great interest to address this specific question in determining the frequency of difficulties in silent reading in Gilles de la Tourette's syndrome individuals as compared to those without Gilles de la Tourette's syndrome. In this way, the so-called Stroop-test should be adequate in addressing this pivotal issue. In this well-known neuropsychological test the subject is asked to orally report the color in which the name of color has been written. The discrepancy between the color of the written word and the name of the color that have been read can challenge the ability of the subject to correctly inhibit the reading (in example the word blue ) in order to say another color (in example red , if the word blue is red colored).

CONCLUSION

Loss of silent reading observed in such patients is suggestive of the failure of the prefrontal inhibitory control on the verbal utterance of inner speech. Further research is needed to confirm these findings.

Developmental processes and brain imaging studies in Tourette syndrome

OBJECTIVES

It is often difficult to discern how findings of a neuroimaging study relate to the pathophysiology of an illness because imaging correlates may variously represent causes, consequences, or epiphenomena of the condition. The objective of this paper is to exemplify the complexities of interpreting neuroimaging data by reviewing anatomical and functional studies of Tourette syndrome (TS).

METHODS

Medline and Psychological Abstracts (PsycInfo) databases were searched for functional and anatomical neuroimaging studies of TS.

RESULTS

9 anatomical and 21 functional cross-sectional imaging studies of TS contributed to this review. Anatomical studies comparing TS patients to age-matched controls have found that lenticular nucleus volumes are reduced in TS adults, while caudate nucleus volumes are reduced in both adults and children with TS. In a study of the cerebral cortex, prefrontal volumes in TS adults were smaller, but in TS children were larger than in those of age-matched controls. Complementing the anatomical findings of reduced volumes of the caudate nucleus in TS, functional studies have suggested that frontal-striatal projections play an important role in the regulation of tic symptoms. The majority of functional studies to date, however, have been limited to the study of adults. These functional studies have yielded variable results that have limited generalizability to the pathophysiology of children with TS.

CONCLUSIONS

Although many of the findings in TS imaging may represent pathological causes of the disease, they may also be indicative of compensatory changes in the nervous system of TS subjects. Prospective studies of young children at risk will be necessary to help clarify the relationship between brain abnormalities and the course of the disease.

Cavum septi pellucidi in Tourette syndrome

BACKGROUND

An enlarged cavum septum pellucidum (CSP) is a putative marker of disturbed brain development, and it has been associated with a variety of neuropsychiatric disorders. The goal of this study was to characterize systematically the CSP and the related cavum vergae in individuals with Tourette syndrome (TS).

METHODS

The overall size and anteroposterior length of the CSP in 161 children (97 with TS and 64 normal pediatric control subjects) and 107 adults (43 with TS and 64 normal adult control subjects) were rated on high-resolution magnetic resonance images in the coronal view. The associations of CSP size with diagnosis and symptom severity scores were assessed using ordinal logistic regression.

RESULTS

CSP size in TS children was significantly smaller than in normal control subjects, and it was inversely associated with attention-deficit/hyperactivity disorder symptom severity in the TS subjects. CSP size was not significantly associated with the comorbid diagnoses of OCD or ADHD. These results were replicated in the independent sample of adults with TS and their same-age control subjects. The presence of a cavum vergae was not significantly associated with a diagnosis of TS.

CONCLUSIONS

These findings suggest that the pathophysiology of TS may involve abnormalities in the early development of the CSP or in the neighboring corpus callosum, septal nuclei, or limbic system.

CNTNAP2 is disrupted in a family with Gilles de la Tourette syndrome and obsessive compulsive disorder

Gilles de la Tourette syndrome (GTS) is a sporadic or inherited complex neuropsychiatric disorder characterized by involuntary motor and vocal tics. There is comorbidity with disorders like obsessive compulsive disorder and attention deficit hyperactivity disorder. Until now linkage analysis has pointed to a number of chromosomal locations, but has failed to identify a clear candidate gene(s). We have investigated a GTS family with a complex chromosomal insertion/translocation involving chromosomes 2 and 7. The affected father [46,XY,inv(2) (p23q22),ins(7;2) (q35-q36;p21p23)] and two affected children [46,XX,der(7)ins(7;2)(q35-q36;p21p23) and 46,XY,der(7)ins(7;2)(q35-q36;p213p23)] share a chromosome 2p21-p23 insertion on chromosome 7q35-q36, thereby interrupting the contactin-associated protein 2 gene (CNTNAP2). This gene encodes a membrane protein located in a specific compartment at the nodes of Ranvier of axons. We hypothesize that disruption or decreased expression of CNTNAP2 could lead to a disturbed distribution of the K(+) channels in the nervous system, thereby influencing conduction and/or repolarization of action potentials, causing unwanted actions or movements in GTS.

Pathophysiology of tics and Tourette syndrome

Tics are involuntary movements that can affect one or more muscles producing simple or complex movements. Blink reflex and startle reflex studies disclose an increased excitability of brainstem interneurons. Analysis of voluntary movement shows that when advance visual information is reduced, patients with tics and Tourette syndrome become progressively slower in completing motor sequences. Sensorimotor integration is abnormally processed. Studies of the contingent negative variation demonstrate abnormalities of movement preparation and the investigation of premotor potentials shows that in some patients tics are not preceded by a normal premotor potential. Magnetic stimulation studies demonstrate an increased excitability of cortical motor cortex. Functional MRI, PET and SPECT studies show abnormal activation of cortical and subcortical areas. Dysfunction of basal ganglia-thalamo-cortical projections affects sensorimotor, language and limbic cortical circuits, and may explain why patients with Tourette syndrome have difficulty in inhibiting unwanted behaviors and impulses.

Disturbed sleep in children with Tourette syndrome: a polysomnographic study

OBJECTIVE

To evaluate objective data on sleep quantity/quality and motor activity during night sleep in children with Tourette syndrome (TS).

METHOD

Polysomnography of 17 unmedicated TS children (ages: 7;11-15;5, mean: 11;10 years) without comorbid attention-deficit hyperactivity disorder (ADHD) was compared with 16 age-, sex- and IQ-matched healthy controls. Sleep analyses according to the procedure of Rechtschaffen and Kales were supplemented by counting epochs with short arousal-related movements (<or=15 s), thus allowing to calculate correlations between motor activity and sleep parameters.

RESULTS

Children with TS demonstrated changes in sleep parameters, including longer sleep period time, longer sleep latency, reduced sleep efficiency, and prolonged wakefulness after sleep onset. Their sleep profiles showed significantly more time awake and less sleep stage II. However, REM sleep variables, slow-wave sleep, and number of sleep stage changes were unaffected. Movement time was similar in both groups, but epochs with short arousal-related movements were increased in TS. Further analyses showed no significant correlations between sleep parameters and nighttime nontic movements, level of psychopathology or tic severity during daytime. Periodic limb movements during sleep (PLMS) were only seen in one TS patient (low PLMS index of 7.8/h).

CONCLUSIONS

Children with TS have disturbed sleep quality with increased arousal phenomena, which both may be intrinsic to the disorder and might trigger tics and other behavioral problems during daytime. This indicates the need for sleep evaluation in patients with TS.

[Gilles de la tourette syndrome: clinical spectrum and management]

OBJECTIVE

To present the current concepts of the clinical phenomenology and natural history of Gilles de la Tourette syndrome (GTS), differential diagnosis with other involuntary movements, its pathogenesis and current management.

DEVELOPMENT

GTS is a disorder characterized by a spectrum of both motor and sonic tics, and a spectrum of behavioral disorders. There is not a biological marker that confirms or refutes the diagnosis of GTS, so this diagnosis remains purely clinical. It has been found to be present in 1 to 3% of school population. An specific cause for GTS is unknown, though most cases appear to occur on an hereditary polygenetic basis. Observations that drugs increasing dopamine neurotransmission, including levodopa and the dopamine receptor agonist pergolide lessen tics, have called into question the dopamine receptor supersensibility hypothesis. The hypothesis proposing basal ganglia and frontostriatal pathways involvement in the pathophysiology of the disorder is the most likely. Frequently, disruption due to tics is overshadowed by comorbid conditions, like obsessive compulsive behaviors, attention deficit hyperactivity disorder, other behavioral disorders and learning disabilities, so the management should be targeted to them.

CONCLUSION

The knowledge about the basic mechanisms and the integral definition of the clinical spectrum of tics and neurobehavioral manifestations, and its natural history in a patient with GTS, allow us to establish a more rational approach for management and prognosis

Delta 9-tetrahydrocannabinol (THC) is effective in the treatment of tics in Tourette syndrome: a 6-week randomized trial

BACKGROUND

Preliminary studies suggested that delta-9-tetrahydrocannabinol (THC), the major psychoactive ingredient of Cannabis sativa L., might be effective in the treatment of Tourette syndrome (TS). This study was performed to investigate for the first time under controlled conditions, over a longer-term treatment period, whether THC is effective and safe in reducing tics in TS.

METHOD

In this randomized, double-blind, placebo-controlled study, 24 patients with TS, according to DSM-III-R criteria, were treated over a 6-week period with up to 10 mg/day of THC. Tics were rated at 6 visits (visit 1, baseline; visits 2-4, during treatment period; visits 5-6, after withdrawal of medication) using the Tourette Syndrome Clinical Global Impressions scale (TS-CGI), the Shapiro Tourette-Syndrome Severity Scale (STSSS), the Yale Global Tic Severity Scale (YGTSS), the self-rated Tourette Syndrome Symptom List (TSSL), and a videotape-based rating scale.

RESULTS

Seven patients dropped out of the study or had to be excluded, but only 1 due to side effects. Using the TS-CGI, STSSS, YGTSS, and video rating scale, we found a significant difference (p <.05) or a trend toward a significant difference (p <.10) between THC and placebo groups at visits 2, 3, and/or 4. Using the TSSL at 10 treatment days (between days 16 and 41) there was a significant difference (p <.05) between both groups. ANOVA as well demonstrated a significant difference (p =.037). No serious adverse effects occurred.

CONCLUSION

Our results provide more evidence that THC is effective and safe in the treatment of tics. It, therefore, can be hypothesized that the central cannabinoid receptor system might play a role in TS pathology.

Gilles de la Tourette's syndrome

Tourette's syndrome (TS) is a childhood onset neurological disorder characterized by motor and vocal tics. It may be associated with a number of co-morbidities including attention deficit hyperactivity disorder, obsessive compulsive symptomatology, and behaviour disorders. Prevalence of TS is higher than previously thought, and may be present in up to 2% of the population. Tourette's syndrome has a significant genetic component. Inheritance may involve several mechanisms including autosomal dominant, bilinear, or polygenic mechanisms. Pathophysiology is still unknown, although is thought to involve striatocortical circuits. Treatment begins with modification of the work and home environment. For more severe cases, medications such as tetrabenazine and neuroleptics may be helpful. Treatment of co-morbidities needs to be considered, as these may result in moredisability than the tics themselves.

A transgenic model of comorbid Tourette's syndrome and obsessive-compulsive disorder circuitry

The tic disorder Tourette's Syndrome (TS) and obsessive-compulsive disorder (OCD) are comorbid behavioral disorders, suggesting a shared but still unknown neuronal basis. To 'circuit-test' such behaviors, we previously engineered transgenic mice expressing a neuropotentiating protein (cholera toxin A1 subunit) within a cortical-limbic subset of dopamine D1-receptor expressing (D1+) neurons known to trigger glutamatergic excitation of orbitofrontal, sensorimotor, limbic and efferent striatal circuits thought to be hyperactive or affected in OCD and TS. These mice exhibited OCD-like behaviors including generalized behavioral perseveration and compulsion-like leaping and grooming-associated pulling and biting of skin and hair. We now report that these OCD-like mice, like humans, also exhibit comorbid TS-like behaviors, including juvenile-onset tics; increased tic number, complexity and flurries; increased tic severity in males; voluntary tic suppression; and tic responsiveness to a non-cataleptic TS+OCD drug therapy (clonidine, 0.01 mg kg(-1)). These data suggest that hormonal gender differences, apart from the influence of genetic or autoimmune etiologic factors, may be sufficient to aggravate tic severity in human TS males compared to TS females. These data also proffer a precise neuronal basis for TS+OCD, wherein tics and primary compulsions or obsessions are evoked by hyperactivity of various cortical-limbic projection neurons' glutamatergic output to efferent targets like the striatum. The 'Cortical-limbic Glutamatergic Neuron' (CGN) neuronal circuit model merges formerly opposed neurotransmitter models of TS and OCD, and is consistent with new clinical reports of increased cortical hyperactivity, striatal glutamate and striatal inhibitory D2 receptors, and reduced striatal responsiveness, in these disorders.

[Dopaminergic modulation of cerebral activity and cognitive functions]

Alterations in dopaminergic system are known to lie in the basis of such diseases as Parkinson's disease, Huntington's disease, Attention Deficit/Hyperactivity Disorder, Tourette syndrome, schizophrenia and drug abuse. This induced broad investigations of dopaminergic system in nearly all the areas of neuroscience. New insights into the pathogenesis of neuropsychiatric diseases have emerged. Research in the field of dopaminergic neurotransmission and memory was awarded Nobel prize in the year 2000. New avenues for the development of more selective drugs have been opened. In their daily practice clinicians are often prescribing medications acting on presynaptic or postsynaptic sites of dopaminergic units. Thus the aim of this review was to renew some knowledge on the architecture of dopaminergic system and also to glance through some of the studies implying its modulating effect on cognitive functions.

[Cognitive disturbances in patients with tics and Tourette's syndrome and their correction with encephabol]

Ninety-four patients with tick hyperkinesis (57) and Tourette's syndrome (37) were studied. Neuropsychological examination revealed memory, attention and audio-motor disturbances and symptoms of dysgraphia and dyslexia. Cognitive impairment may develop before ticks appearance and aggravate during hyperkinesis exacerbation. In the patients with Tourette's syndrome, cortical dysfunctions were mostly pronounced. These cognitive disturbances correlated with the indices of spectral analysis of bioelectrical brain activity in frontal and temporal areas. In 83 patients, an efficacy of encephabol treatment combined with basic therapy was studied. Encephabol given in dosage 200-300 mg daily to patients aged 5-7 years and 600 mg--to those aged over 7 years during 6 weeks significantly improved memory, attention and praxis function.

Tourette syndrome and obsessive-compulsive disorder: event-related brain potentials show similar mechanisms [correction of mechansims] of frontal inhibition but dissimilar target evaluation processes

OBJECTIVES

Tourette Syndrome (TS) and Obsessive-Compulsive Disorders (OCD) share many clinical similarities and show a strong comorbidity. Current theories view a frontal-striatal dysfunction as the underlying cause of many clinical aspects of both disorders. This study sought to investigate mechanisms of conceptual integration and attention in both disorders. We hypothesized that the processing of stimuli with interfering aspects would be altered in a similar way while attentional mechanisms could differ.

METHODS

Event-related brain potentials (ERPs) were recorded in a modified STROOP-paradigm in groups of TS and OCD patients and in a control group. The paradigm involved the presentation of color words in a range of different colors. The subjects had to respond to words of matching word content and color and to ignore mismatching stimuli.

RESULTS

Incongruent stimuli elicited a frontal negative component ("N450") which was enhanced in amplitude and prolonged in latency in both patient groups. Matching stimuli evoked enhanced N2 and P3b components representing target evaluation mechanisms. The OCD group alone displayed a larger P3b amplitude in comparison to both other groups.

CONCLUSIONS

The data are interpreted to indicate that frontal inhibitory mechanisms are altered alike in TS and OCD. In contrast, only the OCD group showed evidence for aberrant target evaluation.

Disturbed monitoring and response inhibition in patients with Gilles de la Tourette syndrome and co-morbid obsessive compulsive disorder

OBJECTIVE

Fronto-striatal dysfunction has been discussed as underlying symptoms of Tourette syndrome (TS) with co-morbid Obsessive Compulsive Disorder (OCD). This suggests possible impairments of executive functions in this disorder, which were therefore targeted in the present study.

METHODS

A comprehensive series of neuropsychological tests examining attention, memory and executive functions was performed in a group of 14 TS/OCD in co-occurrence with OCD patients and a matched control group.

RESULTS

While attentional and memory mechanisms were not altered, TS/OCS patients showed deficits in executive functions predominantly in the areas of response inhibition and action monitoring.

CONCLUSIONS

These findings provide further evidence for a substantial impairment of the frontal-striatal-thalamic-frontal circuit. We propose that the deficits in monitoring, error detection and response inhibition constitute the major impairment of TS/OCD patients in the cognitive domain.

Inhibition of expected movements in Tourette's Syndrome

Tourette's Syndrome (TS) is a basal ganglia (BG) disorder characterized by involuntary motor and vocal tics, impairment of voluntary motor function, and attentional dysfunctions. This experiment aimed to investigate motor reprogramming and inhibitory control in adult TS patients. Ten TS patients and 10 age- and sex-matched controls performed sequences of movements in response to the illumination of LED lights, and were required to interrupt a predictable, reciprocating sequence of leftward and rightward movements in order to move to an unpredictable target that occurred either in the direction opposite to that expected, or in the opposite direction and at twice the expected distance. Results showed that TS patients were no slower than controls in reprogramming the direction and distance of movements, thus showing no overall deficits in inhibitory control. Of interest, however, was a directional asymmetry (right bias) in movement preparation time in TS patients. Patients with TS may have a superiority in allocating attentional resources toward the right side, contralateral to the implicated reduced BG volume in this disorder. These findings extend earlier work reporting anomalous BG lateralization in TS.

Bereitschaftspotential in tic disorders: a preliminary observation

Sensory phenomena in tic disorders such as Tourette's syndrome are known but are substantiated by only a handful of studies. In this preliminary report, we studied premonitory urge, a type of sensory phenomenon in three patients of tic disorders. Bereitschaftspotential, a movement-related cognitive potential indicative of motor preparation, was assessed in these patients. As bereitschaftspotential was observed in all our cases prior to occurrence of tics, it is speculated that tics are not entirely involuntary but are quasi-volitional in nature. Bereitschaftspotential may thus represent a neurophysiological marker of premonitory urge in tic disorders. Implications of exploring the voluntary nature of tics are discussed.

Tourette's syndrome

As our knowledge of Gilles de la Tourette's syndrome increases, so does our appreciation for the pathogenic complexity of this disorder and the challenges associated with its treatment. Advances in the neurosciences have led to new models of pathogenesis, whereas clinical studies have reinvigorated early hypotheses. The interdependent roles of genes and environment in disease formation have yet to be fully elucidated. Results of epidemiological studies have prompted debate on how best to characterise and diagnose this disorder. Absence of ideal anti-tic drugs, combined with knowledge that uncomplicated cases of childhood Tourette's syndrome frequently have a favourable outcome, has led to striking changes in care and treatment of patients. This seminar focuses on these changing views and offers a new perspective on our understanding of the pathogenesis of Tourette's syndrome and on principles for treatment of patients with this disorder.

Tourette syndrome associated with body temperature dysregulation: possible involvement of an idiopathic hypothalamic disorder

Tourette syndrome is a neuropsychiatric disorder that holds the potential to afflict the emotional, familial, social, or scholastic performances of patients with Tourette syndrome in day-to-day life functioning. The disorder is today characterized mainly and diagnosed by clinical observations, yet false-negative results obtained in the diagnosis of Tourette syndrome are numerous and well documented. There is still no laboratory or imaging technique available for the diagnosis of Tourette syndrome. This article reports on changes of the ambient thermal perception (38%) and a circadian dysregulation of the body-temperature profile present in Tourette syndrome probands, irrespective of their chronologic age, sex, or comorbid symptoms. An involvement of idiopathic hypothalamic dysfunctions associated with Tourette syndrome is proposed. Such a phenomenon, if substantiated, could lead to a better understanding of Tourette syndrome and the development of unbiased physical diagnostic criteria of Tourette syndrome and potentiate possible production of novel therapeutic possibilities.

Probabilistic classification learning in Tourette syndrome

Tourette syndrome (TS) is characterised by stereotyped involuntary movements, called tics. Some evidence suggests that structural and functional abnormalities of the basal ganglia may explain these motor symptoms. In this study, the probabilistic classification learning (PCL) test was used to evaluate basal ganglia functions in 10 children with less severe tics (Yale Global Tic Severity Scale (YGTSS) scores<30) and in 10 children with more severe symptoms (YGTSS score>30). In the PCL task, participants are asked to decide whether different combinations of four geometric forms (cues) predict rainy or sunny weather. Each cue is probabilistically related to a weather outcome, and feedback is provided after each decision. After completion of the probabilistic stimulus-response learning procedure, subjects received a transfer test to assess explicit knowledge about the cues. The children with TS exhibited impaired learning in the PCL task in comparison with the 20 healthy control subjects. This impairment was more pronounced in the TS patients with severe symptoms, and there was a significant negative relationship between the final classification performance and the YGTSS scores. The patients showed normal learning in the transfer test. These results suggest that the neostriatal habit learning system, which may play a central role in the acquisition of probabilistic associations, is dysfunctional in TS, especially in the case of more severe motor symptoms. The classification performance and the severity of tics were independent of the explicit knowledge obtained during the test.

Assessment and treatment of vocal tics associated with Tourette's syndrome

A functional analysis suggested that a young man's vocal tics were maintained by automatic reinforcement. A preference assessment was conducted to identify stimuli that effectively competed with the occurrence of vocal tics. When used as components of a reinforcement-based intervention, however, these stimuli were ineffective at reducing the occurrence of vocal tics. Observations conducted in a naturalistic context led to the hypothesis that variations in tics were associated with body positioning. Thus, an additional analysis was conducted to determine if vocal tics occurred less when the participant was lying down versus when he was seated upright. Results suggested that a combination of procedures might be useful in developing idiosyncratic interventions for automatically reinforced problem behavior, such as vocal tics.

[Treatment of tics in Tourette syndrome with atypical antipsychotic drugs]

We reviewed articles in English dealing with research into the effect of atypical antipsychotic drugs on tic reduction in Tourette's syndrome. In Denmark, there are four registered atypical antipsychotic drugs; clozapine, sulpiride, olanzapine, and risperidone. The topic of interest is the effectiveness and side effects of these drugs as compared to the conventional antipsychotic, pimozide, which is today the preferred pharmacological treatment of Tourette's syndrome among the antipsychotics. The conclusion is that risperidone would be a good first-line antipsychotic drug for the treatment of Tourette's syndrome. It is as effective as pimozide, its side effect profile is overall much more favourable, and unlike pimozide it does not contain the risk of causing heart arrhythmia.

Elevated intrasynaptic dopamine release in Tourette's syndrome measured by PET

OBJECTIVE

Dopaminergic abnormalities in frontal-subcortical circuits have been hypothesized as the underlying pathophysiologic mechanism in Tourette's syndrome. The objective of this study was to test the hypothesis that presynaptic dopamine release from the striatum is abnormal in adults with Tourette's syndrome.

METHOD

Seven adults with Tourette's syndrome and five age-matched comparison subjects each received two positron emission tomography (PET) scans with high specific activity [11C]raclopride. The first scan followed an intravenous injection of saline; the second followed an intravenous injection of amphetamine. The relative dopamine release was estimated as the percentage difference in binding potential between the postsaline and postamphetamine scans.

RESULTS

Binding potential determined after the initial [11C]raclopride scan did not significantly differ between Tourette's syndrome and comparison subjects. After amphetamine challenge, the mean value of intrasynaptic dopamine in the putamen (as determined by true equilibrium bolus estimation) increased by 21% in the subjects with Tourette's syndrome and did not change in the comparison subjects; the mean values increased by 16.9% and decreased by 1.8%, respectively, when measured by the constrained method. Dopamine release in the caudate region was not significantly different in the Tourette's syndrome and comparison subjects.

CONCLUSIONS

Greater putamen dopamine release was seen in adults with Tourette's syndrome than in comparison subjects after a pharmacologic challenge with amphetamine. These results suggest that the underlying pathobiology in Tourette's syndrome is a phasic dysfunction of dopamine transmission.

Excessive action monitoring in Tourette syndrome

Tourette Syndrome (TS) has been related to hyperactive basal-ganglia thalamocortical pathways. This suggests that action monitoring might also be hyperactive. The present study used the event-related brain potential (ERP) technique to investigate this hypothesis. A simple "oddball" reaction time experiment was administered to a group of TS patients and a matched control group. In order to investigate variations in attentional allocation separate experimental runs were undertaken with target frequencies of 50% and 80%. The P3b component to targets was taken as an indicator of the target evaluation process and the response locked error-related negativity (ERN) served as an indicator of action monitoring. We hypothesized that the amplitudes of ERN and P3b would vary with respect to target frequency. The TS group would show an overall enhanced ERN but an unchanged P3b.ERN and P3b amplitudes were lower in the 80% target condition than in the 50% condition. In comparison with control subjects TS patients displayed an ERN of overall higher amplitude but with similar variations between target conditions. P3b amplitudes did not differ between groups. The data are interpreted to support the assumption of an abnormal action monitoring system in TS. A number of similarities to Obsessive-Compulsive Disorder are outlined and it is argued that the findings could be related to a hyperactive frontal-striatal-thalamic-frontal circuit.

The segmented regional volumes of the cerebrum and cerebellum in boys with Tourette syndrome

Neuropathological deficits are an etiological factor in Tourette syndrome (TS), and implicate a network linking the basal ganglia and the cerebrum, not a particular single brain region. In this study, the volumes of 20 cerebral and cerebellar regions and their symmetries were measured in normal boys and TS boys by brain magnetic resonance imaging. Brain magnetic resonance images were obtained prospectively in 19 boys with TS and 17 age-matched normal control boys. Cerebral and cerebellar regions were segmented to gray and white fractions using algorithm for semi-automated fuzzy tissue segmentation. The frontal, parietal, temporal, and the occipital lobes and the cerebellum were defined using the semiautomated Talairach atlas-based parcellation method. Boys with TS had smaller total brain volumes than control subjects. In the gray matter, although the smaller brain volume was taken into account, TS boys had a smaller right frontal lobe and a larger left frontal lobe and increased normal asymmetry (left>right). In addition, TS boys had more frontal lobe white matter. There were no significant differences in regions of interest of the parietal, temporal, or the occipital lobes or the cerebellum. These findings suggest that boys with TS may have neuropathological abnormalities in the gray and the white matter of the frontal lobe.

Tc-99m-ECD SPECT brain imaging in children with Tourette's syndrome

We undertook this study to assess the patterns of regional cerebral perfusion (RCP) with SPECT using Technetium- 99m-ethyl cysteinate dimer (Tc-99m-ECD) in children with Tourette's Syndrome (TS), and to compare these with the patterns in a group of normal controls. The study sample consisted of 38 children (7 to 14 years) who met the ICD-10 and DSM/IV criteria for Tourette's Syndrome, and a control group of 18 children (9 to 14 years). The Children's Depression Inventory and Maudsley Obsessional-Compulsive Questionnaire were used for assessment, and the severity of motor and vocal tics were assessed using the Goetz Rating Scale. The RCP values were significantly lower in the TS group in left caudate, cingulum, right cerebellum, left dorsolateral prefrontal, and the left orbital frontal region. A positive correlation was found between the severity of vocal tics and blood flow of mid-cerebellum, right dorsolateral prefrontal and left dorsolateral prefrontal regions. Although no depressive or obsessive patients were included in the study, the depression and obsession scores were found to be negatively correlated with all RCP values, especially in the temporal regions. Further studies are needed to explore the relationship between the hypoperfusion of certain brain areas and the underlying neurophysiology and neurobiology of patients with TS. Additional disturbances such as obsessive-compulsive symptoms and depressive symptoms should also be assessed

The functional neuroanatomy of Tourette's syndrome: an FDG PET study III: functional coupling of regional cerebral metabolic rates

Functional coupling of regional cerebral metabolic rates for glucose measured with [18F]-Fluoro-2-deoxy-D-glucose PET was compared in 18 drug-free patients with Tourette's Syndrome (TS) and 16 age- and sex-matched control subjects. Pearson product-moment correlation matrices containing correlations between metabolic rates in regions sampled throughout the brain were generated independently for TS patients and controls and compared. Significant differences between Z-transformed correlation coefficients were used to identify group differences, and revealed that the connectivity of the ventral striatum was most severely affected in TS. Changes in the coupling of other brain areas-primary motor areas, somatosensory association areas, and insula-also appeared to differentiate TS patients and controls. Evaluation of interrelationships between cortico-striato-thalamo-cortical circuits revealed the existence of functional connections between the motor and lateral orbitofrontal circuits in both groups, however, a reversal in the pattern of these interactions differentiated TS patients and controls. In controls, activity in these circuits appeared to be negatively correlated-i.e. increased activity in one is associated with relative inactivity the other. In TS patients, on the other hand, activity in the motor and lateral orbitofrontal circuits appears to be positively coupled. These results lend further credence to the hypothesis that altered limbic-motor interactions represent a pathophysiological hallmark of this disease.

Tourettism and dystonia after subcortical stroke

The term "tourettism" has been used to describe Tourette syndrome (TS)-like symptoms secondary to some specific cause. Tics associated with attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), or both, are commonly present in TS, but this constellation of symptoms has been rarely attributed to stroke. We describe two boys who suffered a subcortical stroke and subsequently developed hemidystonia, tics, and behavioral comorbidities. Both had right hemispheric stroke involving the basal ganglia at 8 years of age, and in both the latency from the stroke to the onset of left hemidystonia was 2 weeks. In addition to ADHD and OCD, both exhibited cranial-cervical motor tics but no phonic tics. The temporal relationship between the stroke and subsequent TS-like symptoms, as well as the absence of phonic tics and family history of TS symptoms in our patients, argues in favor of a cause and effect relationship, and the observed association provides evidence for an anatomic substrate for TS and related symptoms.

"Dude, you don't have Tourette's:" Tourette's syndrome, beyond the tics

While coprolalia is the most well-known symptom of Tourette's syndrome (TS), it affects only a minority of persons with the condition. TS is a chronic neurobiological condition consisting of vocal and motor tics. Many children with TS have associated obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD), both of which can interfere with school, peer, and family functioning more than the tics themselves. The article distinguishes TS from other tic disorders and reviews literature on epidemiology, etiology, clinical course, and diagnostic and treatment issues. The article discusses the role of primary care pediatric and advanced practice nurses in the diagnosis and management of TS and details helpful interventions in the arenas of personal, family, and educational support, as well as symptom management and indications for medications. The author also suggests areas for future nursing research.

Child clinical/pediatric neuropsychology: some recent advances

The neuropsychological assets and deficits of several types of pediatric neurological disease, disorder, and dysfunction are described. These are examined from the perspective of the syndrome of nonverbal learning disabilities (NLD) and the "white matter model" designed to explain its complex manifestations. It is concluded that children with some of these diseases exhibit the NLD phenotype, whereas others do not. For the most part, the diseases in which the NLD phenotype is particularly evident are those wherein it has been demonstrated that perturbations of white matter (long myelinated fibers) are particularly prominent.

Abnormal line bisection judgements in children with Tourette's syndrome

Tourette's syndrome (TS) has been associated with loss of normal basal ganglia asymmetry, as well as loss of normal functional asymmetry, including the leftward bias on traditional visuospatial tasks such as line bisection and turning bias tests. The aim of the present study was to examine the lateralisation of visuospatial attention in TS. We examined the effect of an irrelevant moving-dot background on line bisection judgements. Nine children with a DSM IV diagnosis of TS participated, in addition to 9 healthy controls, individually matched for age, sex and IQ. Horizontal lines of varying length were presented on a computer screen with either a blank background, or a moving, random-dot field. The dots moved either leftward or rightward across the screen at 40 or 80 mm/s, and participants were instructed to ignore these distracting stimuli when judging the lines. TS children were found to be abnormally right-biased in line bisection in a similar fashion to unmedicated ADHD children who, in a previous study, showed a similar small, yet significant, right-bias in line bisection. Matched controls showed a small, nonsignificant left bias, consistent with past research. Unlike previous findings with hemineglect patients, the irrelevant moving background had no effect on bisection performance for TS children or healthy controls. The present findings suggest a deficit in visuospatial attention consistent with the emerging picture of a lateralised dysfunction of frontostriatal circuitry in TS.

Height distribution in children with Tourette syndrome

Tourette syndrome is characterized by motor and vocal tics, frequently accompanied by attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder, coprolalia, aggressive or self-injurious behavior, and learning disabilities. We investigated the height distribution and clinical characteristics of 38 consecutive patients with Tourette syndrome. Seventeen patients with Tourette syndrome (44.7%) were in the lower height quartile versus 25% from a control group of 44 patients with ADHD (P <.05). The mean standard deviation score differential (patient height - [target height]) was -1.12 +/- 0.82 for patients in the first quartile (group A) compared with 0.42 +/- 0.63 in taller patients with Tourette syndrome (group B) (P < .001). The mean birthweight of boys in group A versus group B was 3023 +/- 351 g and 3363 +/- 486 g, respectively (P <.02); birthweight correlated with standard deviation score (r=.43). Current weight relative to height was normal. Conduct disorder and/or self-injurious behavior were more common in group A patients (P < .05). Relative short stature appears common in Tourette syndrome, and its presence with other features may implicate a neurotransmitter system that interacts with neuroendocrine pathways, controlling height.

Movement control of manipulative tasks in patients with Gilles de la Tourette syndrome

When a hand-held object is moved, grip and load force are accurately coordinated for establishing grasp stability. In the present work, the question was raised whether patients with Gilles de la Tourette syndrome (TS), who show tic-like movements, are impaired in grip-load force control when executing a manipulative task. To this end, we assessed force regulation during action patterns that required rhythmical unimanual or bimanual (iso-directional/anti-directional) movements. Results showed that the profile of grip-load force ratio was characterized by maxima and minima that were realized at upward and downward hand positions, respectively. TS patients showed increased force ratios during unimanual and bimanual movements, compared with control subjects, indicative of an inaccurate specification of the precision grip. Functional imaging data complemented the behavioural results and revealed that secondary motor areas showed no (or greatly reduced) activation in TS patients when executing the movement tasks as compared with baseline conditions. This indicates that the metabolic level in the secondary motor areas was equal during rest and task performance. At the neuronal level, this observation suggests that these cortical areas were continuously involved in movement preparation. Based on these data, we conclude that the ongoing activation of secondary motor areas may be explained by the TS patients' involuntary urges to move. Accordingly, interference will prevent an accurate planning of voluntary behaviour. Together, these findings reveal modulations in movement organization in patients with TS and exemplify degrading consequences for manual function.

Early-onset Tourette syndrome with reversible autistic behaviour: a dysmaturational disorder

Early-onset Tourette syndrome comorbid with reversible autistic behaviour is described in twelve young males. After a normal gestation, delivery and first-year development, regression set in between the age of one and two with loss of various abilities and the emergence of autistic behaviour. At this time, or slightly later, they showed multiple motor and vocal tics, simple and complex: the latter could also be traced to most of their parents. Following an intervention based on intense cuddling, motor activation and paedagogic guidance, these children's abilities rapidly improved, reaching at follow-up a normal or borderline intellectual functioning and with the disappearance of their initial autistic behaviour. At follow-up tics were present in all, usually with the features of a full-blown Tourette syndrome, often comorbid with ADHD, and in some cases with OCD.

Gilles de la Tourette syndrome in a child with congenital deafness

We present the case of a 10-year-old boy, Sam, with congenital deafness and Gilles de la Tourette Syndrome (GTS). GTS is characterised by multiple motor tics and one or more vocal tics that wax and wane. Due to his deafness Sam never developed vocal language but instead used sign language from the age of four. His tic disorder rapidly accelerated from the age of seven over a six-month period and soon sign language was incorporated into tics as complex "vocal" tics. Bursting out "words" in sign language would also occur in front of people unfamiliar with sign language and often with an obscene content although this was not evident to someone not trained in sign language. To our knowledge this is the first reported case of a congenital deaf child with GTS. The case presented here supports previously published work that the intentional share of the tics in GTS is very small. This case also questions former theories on which regions and circuits of the brain are involved in GTS.

Tactile prepuff inhibition of startle in children with Tourette's syndrome: in search of an "fMRI-friendly" startle paradigm

BACKGROUND

Functional magnetic resonance imaging (fMRI) studies in neuropsychiatric populations will be enhanced by "on-line" tasks that assess brain activation linked to neurocognitive and psychophysiological functions. In some cases, task modifications may be required for use in an fMRI environment. Prepulse inhibition (PPI) of the startle reflex is an operational measure of sensorimotor gating that is deficient in specific neuropsychiatric disorders, including schizophrenia, Huntington's disease, and Tourette's syndrome (TS). This study examined whether a modified "fMRI-friendly" PPI paradigm is suitable for use in children and adequately sensitive to detect PPI deficits in TS.

METHODS

Bilateral eyeblink PPI was measured in children using chin air puffs to elicit startle and prepuffs to the dorsal hand surface as inhibiting stimuli. This paradigm involved no metallic objects or acoustic stimuli, making it suitable for an fMRI environment that is magnetically sensitive and acoustically complex. Children were also assessed in a "standard" acoustic PPI paradigm.

RESULTS

Robust startle was elicited via either puffs or noise bursts, and these responses were inhibited by prepuffs and prepulses, respectively. Compared to control subjects, children with TS exhibited comparable startle magnitude and habituation but significantly reduced prepuff inhibition and acoustic PPI.

CONCLUSIONS

Sensorimotor gating can be assessed in an "fMRI-friendly" paradigm that detects inhibitory deficits in TS.

Control of volitional and reflexive saccades in Tourette's syndrome

Tourette's syndrome is characterized by involuntary tics and, although the underlying pathogenesis and pathophysiology of Tourette's syndrome remains unclear, it is suspected that basal ganglia structures are involved. The basal ganglia also play an important role in the control of saccadic eye movements and we therefore hypothesize that Tourette's syndrome patients have abnormal control of saccadic eye movements. In this study, 10 subjects with Tourette's syndrome and 10 age- and sex-matched controls performed four different oculomotor paradigms requiring the execution and/or suppression of reflexive and/or voluntary saccades. In the immediate saccade tasks, subjects were required to look either toward (pro-saccade task) or away from (anti-saccade task) a peripheral target as soon as it appeared. In the delayed saccade tasks, subjects were instructed to wait for a central fixation point to disappear before initiating eye movements. Among Tourette's syndrome subjects, saccadic reaction times were longer in all tasks. Saccadic amplitudes were smaller in Tourette's syndrome subjects, and they made more saccades to reach the eccentric target. The occurrence of direction errors (i.e. reflexive pro-saccades on anti-saccade trials) was normal in the immediate anti-saccade task, suggesting that the ability to inhibit reflexive saccades towards novel stimuli was not impaired in Tourette's syndrome. Timing errors (i.e. eye movements made prior to disappearance of the central fixation point in delayed saccade tasks) were significantly greater among Tourette's syndrome subjects. Moreover, these errors were predominantly made towards the first target of the remembered sequence in a delayed memory-guided sequential saccade task. These results indicate that the ability to inhibit or delay planned motor programmes is significantly impaired in Tourette's syndrome. We hypothesize that altered cortical-basal ganglia circuitry leads to reduced cortical inhibition making it harder for Tourette's syndrome subjects to withhold the execution of planned motor programmes.