Do prenatal and perinatal complications influence tic severity in patients with gilles de la tourette syndrome?

OBJECTIVE: Evidence for the role of complex genetics in the clinical expression of Gilles de la Tourette (GTS) is widespread. Streptococcal autoimmunity as another aetiology is under intense investigation but there is relatively little evidence for other environmental factors. It has long been suggested that perinatal problems increase vulnerability to Tourette syndrome. The aim of this project was to investigate whether prenatal or perinatal complications are associated with an increased tic severity in patients who develop GTS.

METHOD: 193 patients with GTS attending St George's Hospital between 2004-2011 were retrospectively reviewed for exposure to prenatal and perinatal complications (Mean age 20.3 ± 13.55; age range 3-76; 145 males: 48 females) The Yale Global Tic Severity Score (YGTSS) was used to assess current tic severity, giving each patient a score out of 25 for phonic and motor tics, and a score out of 50 for total tic severity. An additional score was given for overall impairment caused by GTS ranging from 0 (no impairment) to 50 (severe impairment). Records were also reviewed for the presence of current co-morbidity associated with GTS (ADHD/OCB/OCD); and assessed for any family history of GTS, tics, ADHD, OCD or OCB. The mean tic severity and impairment scores for the group who reported prenatal or perinatal complications were assessed in comparison to those of the group reporting no complications.

RESULTS: Perinatal complications were reported in 92 out of 193 patients (48%). The mean total tic score compared to patients with a history of complications was 25.94 vs. 24.88 and the mean impairment scores were 29.01 vs. 25.24 respectively.

CONCLUSION: Previous multivariate analyses have correlated perinatal factors with tic severity e.g. maternal smoking. In this cohort, prenatal and perinatal complications were not associated with increased motor, phonic or total tic severity or increase in impairment and there was no increased level of comorbidity or family history. Limitations include recall bias for perinatal events, a univariate approach and the measure of severity in all studies which applies to one time-point in a fluctuating condition.