Postural control anomalies and gait dysfunction in Tourette's syndrome: a systematic review and meta-analysis

BACKGROUND: Alongside typical manifestations such as motor and vocal tics, recent research has unveiled abnormalities in postural control and gait in patients with Tourette's syndrome (TS). METHODS: To investigate abnormalities in postural control and gait in patients with TS an extensive search of the literature was performed on PubMed, EMBASE, and Cochrane Library, following PRISMA guidelines. The ROBINS-I tool was used for risk of bias assessment. The Newcastle Ottawa scale was used to evaluate the certainty of evidence. Meta-analysis was conducted using a random-effects model to calculate the Standardized Mean Difference of Center of Pressure velocity and range across four clinical studies comparing children with TS to healthy controls. FINDINGS: Six case-control studies were included. Analysis of the selected studies revealed consistent findings of subclinical postural control deficits in patients with TS, characterized by increased sway area and increased range and velocity of center of pressure displacements. Reduced postural stability was found upon altered sensory or attention-demanding tasks. Minor gait dysfunctions were also found, including irregular step length and a larger step length differential. Importantly, these abnormalities appeared to be independent of tic severity, medications and comorbidities, suggesting their intrinsic nature in the context of TS. INTERPRETATION: Postural control deficit and gait dysfunction may be additional phenotypic correlates of cortical connectivity abnormalities in TS. Consequently, testing these domains in the overall assessment of patients with TS is warranted, also to develop effective and targeted therapeutic interventions addressing these aspects of the disease.