Visual Temporal Perception in Parkinson’s Disease Analyzed Using a Computer-Generated Graphical Tool

Non-motor symptoms of Parkinson’s Disease (PD) are present in all stages of the disease, significantly affecting patient quality of life. Some previous work on temporal perception has seen abnormalities occurring in PD, highlighting the Basal Ganglia’s (BG) role on this perception. However, these studies have not considered patient perceptual ability based on the tested time scale, even though the BG’s postulated influence on temporal processing is limited to certain time scales. Furthermore, it is not clear what effect Levodopa medication has on temporal perception for PD patients. This study examines the perception of vision-based temporal perception in different time scales for PD patients, and the effect of Levodopa medication via a two-forced alternative choice task using a computer-generated graphical tool. For this, perceptual ability (quantified using the subject’s difference threshold obtained through cumulative Gaussian functions) of 21 patients with PD was evaluated OFF and ON Levodopa medication, compared to 17 age-matched healthy participants. Individuals with PD displayed no impairments in perceiving time in the range of milliseconds, however in the range of seconds temporal perception was significantly impaired. This provides evidence for current timing models involving cerebellar control for millisecond timing, and BG influenced timing in the range of seconds to minutes. Furthermore, Levodopa showed no significant effects on visual temporal discrimination.