WORD-FREQUENCY MONITORING IN PARKINSON DISEASE - AN ANALYSIS OF ACCURACY AND PRECISION

The judgment of frequency of occurrence of stimuli appearing in a task is a complicated decision. This decision can be independently analyzed using estimates of subject accuracy (where their estimate resembles the true frequency of the stimuli) and precision (sensitive to response bias). In this study, the accuracy and precision of Parkison's disease (PD) patients estimates of the frequency of occurrence of word stimuli were analyzed. The results indicated that the accuracy estimates of PD patients were not significantly different from normal controls whereas their precision of frequency judgments was impaired. Poorer precision scores were associated with fewer categories achieved on the Wisconsin Card Sorting Test. Using accuracy and precision estimates should improve the characterization of the cognitive processes required in frequency judgments.