Modulation of time in Parkinson's disease: a review and perspective on cognitive rehabilitation

Abstract

Time cognition is an essential function of human life, and the impairment affects a variety of behavioral patterns. Neuropsychological approaches have been widely demonstrated that Parkinson's disease (PD) impairs time cognitive processing. Many researchers believe that time cognitive deficits are due to the basal ganglia, including the striatum or subthalamic nucleus, which is the pathomechanism of PD, and are considered to produce only transient recovery due to medication effects. In this perspective, we focus on a compensatory property of brain function based on the improved time cognition independent of basal ganglia recovery and an overlapping structure on the neural network based on an improved inhibitory system by time cognitive training, in patients with PD. This perspective may lead to restoring multiple functions through single function training.

Keywords: Parkinson’s disease; compensatory property; learning; overlapping structure; rehabilitation; time cognition.

Figure 1

Measurements of time cognition. (A) Time production task. The duration to be generated is indicated by a number on the screen, and the participant creates a subjective duration by button pressing the start and end of the measurement. For example, if a participant creates a 6-second duration when a 10-second duration is required, he or she has underestimated the duration. By measuring subjective duration relative to physical duration, it is possible to evaluate an individual’s reference memory created by previous experience. (B) Time bisection task. This task is comprised of two sessions: In the learning session, figures with relatively short and relatively long durations are randomly presented to the subjects dozens of times for them to learn the respective durations of figures. Then, in the test session, the participant determines whether the duration of figure presented is closer to which of the two previously learned long/short durations. It requires judging the current duration concerning the immediately preceding learned duration and does not involve much reference memory, allowing the perceptual aspect of the duration to be evaluated. (C) Time reproduction task. A figure of specific duration is presented, and the participant reproduces the same duration. For example, even if a participant subjectively judged 6-second duration for physical 10-second duration, if the subject can reproduce the subjective 6-second immediately afterward, the resulting output is the duration of the 10-second. It is possible to assess the working memory of duration rather than reference memory.

Figure 2

Schematic illustration for brain regions involved in time cognition and response inhibition functions. The blue solid circles indicated the regions related to time cognition function and red dotted circles indicated the regions related to response inhibition function. Of these, the DLPFC, STN, insula cortex, substantia nigra, and striatum overlap in both functions.