Impaired Tactile Spatial Discrimination in Parkinson's disease

ABSTRACT

BACKGROUND: The basal ganglia plays a major role in regulating motor, cognitive and emotional functions. In addition, it has been proposed that the functions of the basal ganglia is also related to control of sensory discrimination and sensorimotor integration. One possible way to test this hypothesis would be to investigate sensory functions in patients with various diseases affecting basal ganglia functions. Since idiopathic Parkinson's disease (IPD) is caused by selective impairment of basal ganglia functions, it could be a good model for this purpose. METHODS: We measured the grating resolution threshold (GRT) using the JVP (Johnson-Van Boven-Phillips) dome in 52 patients with IPD and 25 age-matched healthy controls. Statistical analysis employed unpaired t-test, paired t-test and simple regression analysis. P-values less than 0.05 were considered as significant. RESULTS: Patients showed significantly higher GRT than controls (3.07 +/- 0.74 vs 2.03 +/- 0.80; p<0.05). In patients, the mean GRT was not different between symptomatically dominant and non-dominant hands (3.10 +/- 0.95 vs 2.93 +/- 0.82). In the patients with hemiparkinsonism, GRT was also significantly higher in asymptomatic hands compared with controls (3.00 +/- 0.71 vs 2.03 +/- 0.80; p<0.05). The severity of sensory dysfunction in patients was not correlated with symptom duration or to symptom severity, measured by the modified Columbia rating scale (MCRS). CONCLUSIONS: The present results demonstrate that spatial discrimination is impaired in IPD, suggesting the basal ganglia plays a role in sensory regulation.