Abnormalities of the acoustic startle reflex and reaction time in gilles de la tourette syndrome.

OBJECTIVE

To study the startle reflex and the effect of the startle reflex stimulus over reaction time (start-react effect) in Gilles de la Tourette syndrome (GTS).

METHOD: Ten GTS patients and ten matched healthy volunteers underwent a simple RT paradigm (4 blocks of 50 trials). Forty acoustic startle reflex stimuli (110 dB) were randomly delivered with a 20% occurrence probability and presented unexpectedly at the same time as the imperative stimuli of the RT. Variables of interest were: amplitude, onset latency, degree of spread and rate of habituation of the startle response, and RT and the start-react effect caused by the startle stimuli.

RESULTS

GTS patients showed a significantly higher amplitude, a major degree of spread and fewer habituation phenomena of the startle reflex. GTS patients showed poorer non statistically significant RT performance compared to controls, with a significant correlation between RT and severity of the disease. The start-react effect was significantly less pronounced in GTS patients.

CONCLUSIONS

The present study confirms that GTS has an exaggerated startle reflex response and extend the spectrum of abnormalities to the start-react effect. A state of dopaminergic hyperactivity may have contributed to these results.