Anomalous visual response in Tourette’s syndrome

Abstract

Because haloperidol, a dopamine antagonist, is often successfully used in Tourette’s syndrome, this condition is commonly thought to involve an anomaly of dopamine neurotransmission. It is also believed that the human retina contains dopaminergic amacrine, interamacrine, and interplexiform cells. Since these retinal cells could represent the neural substrate of the psychophysical transientlike response, we conducted a detailed visual study of a Tourette’s patient. Our subject is a 23-year-old male who has been on haloperidol medication since being diagnosed as having Tourette’s syndrome at age 10. He exhibited very good visual acuity, essentially normal visual fields, and steady fixation.

Quantitative layer-by-layer perimetric testing was performed at fixation and different parafoveal eccentricities. All loci tested revealed normal sustained-like response. The transient-like response was often subnormal at 10 degrees eccentricity for random, noncongruous loci in each eye. During a brief gastrointestinal illness which caused interruption of his haloperidol medication, the patient’s transient-like response became supranormal at certain affected test sites. These same data points became subnormal responses after the patient resumed therapy.