Differential Temporal Perception Abilities in Parkinson\u2019s Disease Patients Based on Timing Magnitude

Matthew Bernardinis,Rajni V Patel,S Farokh Atashzar,Mandar S Jog

doi:10.1038/s41598-019-55827-y

Matthew Bernardinis, Rajni V Patel + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-55827-y

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Abstract

Non-motor symptoms in Parkinson’s Disease (PD) predate motor symptoms and substantially decrease quality of life; however, detection, monitoring, and treatments are unavailable for many of these symptoms. Temporal perception abnormalities in PD are generally attributed to altered Basal Ganglia (BG) function. Present studies are confounded by motor control facilitating movements that are integrated into protocols assessing temporal perception. There is uncertainty regarding the BG’s influence on timing processes of different time scales and how PD therapies affect this perception. In this study, PD patients using Levodopa (n = 25), Deep Brain Stimulation (DBS; n = 6), de novo patients (n = 6), and healthy controls (n = 17) completed a visual temporal perception task in seconds and sub-section timing scales using a computer-generated graphical tool. For all patient groups, there were no impairments seen at the smaller tested magnitudes (using sub-second timing). However, all PD groups displayed significant impairments at the larger tested magnitudes (using interval timing). Neither Levodopa nor DBS therapy led to significant improvements in timing abilities. Levodopa resulted in a strong trend towards impairing timing processes and caused a deterioration in perceptual coherency according to Weber’s Law. It is shown that timing abnormalities in PD occur in the seconds range but do not extend to the sub-second range. Furthermore, observed timing deficits were shown to not be solely caused by motor deficiency. This provides evidence to support internal clock models involving the BG (among other neural regions) in interval timing, and cerebellar control of sub-second timing. This study also revealed significant temporal perception deficits in recently diagnosed PD patients; thus, temporal perception abnormalities might act as an early disease marker, with the graphical tool showing potential for disease monitoring.

Highlights

Of the studied non-motor deficits occurring in Parkinson’s Disease (PD), abnormalities in some perceptual processes have been observed[4]
Levodopa and Deep Brain Stimulation (DBS) therapies were shown to elicit minimal effect on the temporal discrimination, and, perceptual coherency was generally disrupted in PD patients
These findings provide an interesting view on how patients at different disease stages and utilizing different treatments are affected with regard to temporal perception ability

Summary

Introduction

Of the studied non-motor deficits occurring in PD, abnormalities in some perceptual processes have been observed[4]. Further shortcomings of work studying temporal perception in PD are seen with few perceptual discrimination (ability to discern between two stimuli differing in magnitude) studies occurring in favour of detection (ability to detect stimuli apart from a baseline) tasks, with many of these past discrimination studies involving goal-directed movements and one neural timing mechanism (i.e. interval timing in the range of seconds)[21,22] This is exemplified in research conducted by Artieda et al that concluded that those with PD display deficits in both motor timing tasks and time estimation tasks across multiple sensory modalities[14,19]. This paper systematically analyzes visual temporal discrimination at different time scales in PD patients independent of goal directed movements that could influence participant timing ability, while evaluating the effect of the two common PD therapies and analyzing the coherency of the perceptual capability being studied

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