Postural control anomalies in children with Tourette syndrome

Comorbidity of physical illnesses and mental disorders in outpatients with tic disorders: a retrospective study using the outpatient case system

Background

Tic disorder, a chronic neurodevelopmental disorder that typically onsets during childhood, is characterized by sudden, involuntary, rapid, and non-rhythmic motor and vocal tics. Individuals with tic disorders often experience physical health issues. The purpose of our retrospective analysis was to elucidate the common comorbid physical diseases and mental disorders and their characteristics of outpatient children with tic disorders in a large public children's hospital in China over the past 5 years.

Methods

Participants were outpatients with tic disorders who visited Beijing Children's Hospital, from January 1, 2018 to December 31, 2022. After the inclusion screening, a total of 523,462 patient visits were included in the analysis. Based on the International Classification of Diseases, 10th Revision (ICD-10) diagnostic system, we employed descriptive statistical analysis to examine the frequently co-occurring somatic diseases in patients with tic disorders, as well as the influence of variables such as age and seasonal variation on these comorbidities.

Results

The top five diseases of total outpatient visits were as follows: Respiratory diseases, Mental and behavioral disorders, Diseases of the eye and adnexal, Digestive disorders, Diseases of the skin and subcutaneous tissue. Among the top five comorbid disease system, the most commonly third- level classification of diseases were upper respiratory tract infections, attention deficit and hyperactivity disorder, conjunctivitis, dyspepsia, dermatitis. Respiratory system diseases experienced a peak in April, while the other four types of diseases reached their peak in August. Additionally, each disease system showed the lowest number of patient visits in February. Additional to the mental and behavioral disorders, the other four disease systems would experience a peak in medical visits between the ages of 4 and 6.

Conclusion

Our study highlighted the most common physical diseases and mental disorders in tic disorders, namely the respiratory diseases, specifically upper respiratory tract infections, and mental and behavioral disorders, with ADHD being the most common co-occurring condition.

Assessment of gait and sensorimotor deficits in the D1CT-7 mouse model of Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by multiple motor and phonic tics. While TS patients have been also shown to exhibit subtle abnormalities of sensorimotor integration and gait, animal models of this disorder are seldom tested for these functions. To fill this gap, we assessed gait and sensorimotor integration in the D1CT-7 mouse, one of the best-validated animal models of TS. D1CT-7 mice exhibit spontaneous tic-like manifestations, which, in line with the clinical phenomenology of TS, are markedly exacerbated by environmental stress. Thus, to verify whether stress may affect sensorimotor integration and gait functions in D1CT-7 mice, we subjected these animals to a 20-min session of spatial confinement, an environmental stressor that was recently shown to worsen tic-like manifestations. Immediately following this manipulation (or no confinement, for controls), animals were subjected to either the sticky-tape task, to test for sensorimotor integration; or a 60-min session in an open field (42×42cm) force-plate actometer for gait analysis. Gait analyses included spatial, temporal, and dynamic (force) parameters. D1CT-7 mice displayed a longer latency to remove a sticky tape, indicating marked impairments in sensorimotor integration; furthermore, these mutants exhibited shortened stride length, increased stride rate, nearly equal early-phase velocity, and higher late-phase velocity. D1CT-7 mice also ran with greater force amplitude than wild-type (WT) littermates. None of these phenotypes was worsened by spatial confinement. These results highlight the potential importance of testing sensorimotor integration and gait functions as a phenotypic correlate of cortical connectivity deficits in animal models of TS.

Deficits in sensory organization for postural stability in children with Tourette syndrome

Tourette syndrome (TS) is a childhood-onset developmental disorder characterized by involuntary motor and vocal tics. Previous studies have indicated that children with TS demonstrate postural control anomalies when standing. The aim of this study was to compare postural stability under normal and altered sensory conditions in children with TS and healthy control (HC) children. A convenience sample of twelve children with TS (9 boys and 3 girls; 9.4 ± 1.1 yr) and 12 HC age- and gender-matched children (9.2 ± 1.1 yr) participated in this study. The Sensory Organization Test (SOT) was used to assess postural stability under six altered sensory conditions (1. normal vision, fixed support; 2. eyes closed, fixed support; 3. vision sway-referenced, fixed support; 4. normal vision, support sway-referenced; 5. eyes closed, support surface sway-referenced; 6. both vision and support surface sway-referenced) using the SMART Balance Master® 8.2 (NeuroCom® International, Inc, Clackamas, OR, USA). The results showed significant differences between the two groups in conditions 5 and 6 (p=0.003 and 0.002, respectively). The mean composite equilibrium score in children with TS was significantly lower than that of HC children (p<0.000). The results suggested that children with TS had greater difficulty in maintaining postural stability, especially when vestibular information was challenged. The results of this study provide supporting evidence for possible deficits in impaired access to vestibular information and sensorimotor integration of postural control in children with TS.

Spatio-temporal gait characteristics in children with Tourette syndrome: a preliminary study

Earlier studies had suggested that variability of stride length in gait is a pathological sign of basal ganglia disease. Some evidence implicates the involvement of the basal ganglia and related thalamocortical circuitry in Tourette syndrome (TS). To date, the gait of subjects with TS has only discussed in case reports. This investigation compared the spatial and temporal gait characteristics of a sample of children with TS (N=8) with those of healthy controls (HC; N=8). All children were instructed to walk under two speed conditions: "preferred" and "fastest." Gait parameters were measured using an electronic walkway. Spatial and temporal gait parameters were compared using a two-way (group)×(conditions) repeated measures ANOVA. The preliminary results suggested that similar to HC children, children with TS were capable of regulating temporal characteristics of gait based on walking speed. They also exhibited subtle gait anomalies such as irregular step length, as evidenced by significant differences in step length differential (p=0.003), detectable despite the small sample size. These findings warrant further investigation into the gait control of children with TS.

Effects of a secondary task on postural control in children with Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by involuntary motor and vocal tics. Sub-clinical postural control anomalies have recently been reported in children with TS. The goal of the present study was to determine whether these anomalies interact with attention in postural control. Thirty-two younger (below 10 years) and 21 older (above 10 years) children with TS were compared to 13 younger and 15 older age-matched controls. Postural control was examined during standing with and without a secondary visual attention task. Sway velocity was higher in younger children than older ones and also higher in children with TS than in controls. The secondary task exacerbated the velocity anomalies in younger children with TS. The effects were independent of tic severity, medication, and attention deficit. The results suggest that postural control anomalies in TS are sensitive to attentional requirements.

Patterns of postural sway in high anxious children

Background

Current research suggests that elevated levels of anxiety have a negative impact on the regulation of balance. However, most studies to date examined only global balance performance, with little attention to the way body posture is organized in space and time. The aim of this study is to examine whether posturographic measures can reveal (sub)clinical balance deficits in children with high levels of anxiety.

Methods

We examined the spatio-temporal structure of the centre-of-pressure (COP) fluctuations in children with elevated levels of anxiety and a group of typically developing children while maintaining quiet stance on a force plate in various balance challenging conditions. Balance was challenged by adopting sensory manipulations (standing with eyes closed and/or standing on a foam surface) and using a cognitive manipulation (dual-tasking).

Results

Across groups, postural performance was strongly influenced by the sensory manipulations, and hardly by the cognitive manipulation. We also found that children with anxiety had overall more postural sway, and that their postural sway was overall less complex than sway of typically developing children. The postural differences between groups were present even in the simple baseline condition, and the group differences became larger with increasing task difficulty.

Conclusion

The pattern of postural sway suggests that balance is overall less stable and more attention demanding in children with anxiety than typically developing children. The findings provide further evidence for a neuro-behavioral link between psychopathology and the effectiveness of postural control.

Gross motor performance and self-perceived motor competence in children with emotional, behavioural, and pervasive developmental disorders: a review

AIMS

Motor performance and self-perceived motor competence have a great impact on the psychosocial development of children in general. In this review, empirical studies of gross motor performance and self-perception of motor competence in children with emotional (depression and anxiety), behavioural, and pervasive developmental disorders are scrutinized, with the objective of identifying specific motor characteristics that may be relevant to clinical practice.

METHOD

A systematic search of studies published between 1997 and 2007 was performed using nine search engines.

RESULTS

Children in all three categories (emotional, behavioural, and pervasive developmental disorders) exhibit poor gross motor performance and problematic self-perception of motor competence, with certain indications of disorder-specific characteristics. In particular, children with emotional disorders have balance problems and self-perceived motor incompetence; children with behavioural disorders show poor ball skills and tend to overestimate their motor performance; children with pervasive developmental disorders demonstrate poor gross motor performance and self-perceived motor incompetence. As a result, children with developmental and emotional disorders are restricted in participating in games and play, which may lead to inactive lifestyles and further disruption of their psychosocial and physical development.

INTERPRETATION

Motor problems need more, to some extent disorder-specific, attention in clinical practice than has been provided to date.

Prefrontal and anterior cingulate cortex abnormalities in Tourette Syndrome: evidence from voxel-based morphometry and magnetization transfer imaging

Background

Pathophysiological evidence suggests an involvement of fronto-striatal circuits in Tourette syndrome (TS). To identify TS related abnormalities in gray and white matter we used optimized voxel-based morphometry (VBM) and magnetization transfer imaging (MTI) which are more sensitive to tissue alterations than conventional MRI and provide a quantitative measure of macrostructural integrity.

Methods

Volumetric high-resolution anatomical T1-weighted MRI and MTI were acquired in 19 adult, unmedicated male TS patients without co-morbidities and 20 age- and sex-matched controls on a 1.5 Tesla neuro-optimized GE scanner. Images were pre-processed and analyzed using an optimized version of VBM in SPM2.

Results

Using VBM, TS patients showed significant decreases in gray matter volumes in prefrontal areas, the anterior cingulate gyrus, sensorimotor areas, left caudate nucleus and left postcentral gyrus. Decreases in white matter volumes were detected in the right inferior frontal gyrus, the left superior frontal gyrus and the anterior corpus callosum. Increases were found in the left middle frontal gyrus and left sensorimotor areas. In MTI, white matter reductions were seen in the right medial frontal gyrus, the inferior frontal gyrus bilaterally and the right cingulate gyrus. Tic severity was negatively correlated with orbitofrontal structures, the right cingulate gyrus and parts of the parietal-temporal-occipital association cortex bilaterally.

Conclusion

Our MRI in vivo neuropathological findings using two sensitive and unbiased techniques support the hypothesis that alterations in frontostriatal circuitries underlie TS pathology. We suggest that anomalous frontal lobe association and projection fiber bundles cause disinhibition of the cingulate gyrus and abnormal basal ganglia function.

Structural changes in the somatosensory system correlate with tic severity in Gilles de la Tourette syndrome

Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder characterized by multiple motor and vocal tics. Previous structural MRI studies have identified regional abnormalities in grey matter, especially in the basal ganglia. These findings are consistent with the assumption of alterations in cortico-striato-thalamo-cortical circuits and dopaminergic neurotransmission playing a major role in the pathophysiology of GTS. Additionally, recent imaging studies suggested an involvement of sensory-motor cortices in the pathophysiology of GTS. However, little is known about the role of white matter changes in GTS. In this study, we aimed to examine whether GTS is associated with abnormalities in white matter microstructure and whether these changes are correlated with tic severity. In a morphometric study based on diffusion tensor MRI of the whole brain, we compared brain tissue diffusion characteristics between 15 unmedicated adults with GTS without psychiatric co-morbidity and 15 healthy age- and sex-matched controls. We performed voxel-based morphometry (VBM) of regional fractional anisotropy (FA) values to identify regional differences in white matter microstructure between the groups. We also tested for a linear relationship between regional FA values and clinical scores of tic severity. Probabilistic fibre tracking was applied to characterize anatomical connectivity of those areas showing differences in regional FA. Compared with healthy controls, GTS patients showed bilateral FA increases in white matter underlying the post- and precentral gyrus, below the left supplementary motor area, and in the right ventro-postero-lateral part of the thalamus. The peak increase in FA was located below the left postcentral gyrus. Probabilistic tractography identified transcallosal and ipsilateral cerebello-thalamo-cortical pathways of the somatosensory system passing through this subcortical region. In patients, regional FA in this region showed an inverse linear relationship with tic severity. These findings demonstrate, for the first time, structural alterations in somatosensory pathways in GTS. Changes of water diffusion characteristics point towards reduced branching in somatosensory pathways in GTS patients. The negative correlation between higher regional FA values and fewer tics suggests that these alterations of white matter microstructure represent adaptive reorganization of somatosensory processing in GTS.