Abnormal somatosensory temporal discrimination in Parkinson’s disease: Pathophysiological correlates and role in motor control deficits

Publication date: Available online 13 December 2017
Source:Clinical Neurophysiology
Author(s): Myung Sik Lee, Myung Jun Lee, Antonella Conte, Alfredo Berardelli
ObjectiveThe somatosensory temporal discrimination threshold (STDT), defined as the shortest time interval required for two tactile stimuli to be perceived as separate, is longer in patients with Parkinson's disease (PD). In this review, we discuss STDT findings in healthy subjects and in PD patients and the relationship between altered STDT and motor disturbances.MethodsA search was conducted on PubMed for papers dealing with PD and temporal discrimination published from January 1990 to July 2017.ResultsAbnormal STDT in PD correlates with disease duration, disease severity and degree of nigrostriatal dopamine loss, and responds to dopaminergic medication. In PD, a prolonged STDT does not correlate, or only marginally correlates, with clinically assessed bradykinesia of finger tapping. By contrast, a prolonged STDT correlates with the variability in amplitude and speed of finger tapping as assessed by means of neurophysiological techniques and may contribute to impaired finger dexterity in PD.ConclusionsWe suggest that abnormal temporal processing of sensory information in PD generates incorrect signals for the execution and control of voluntary movements.SignificanceThis review sheds light on unsolved questions regarding the relationship between STDT alterations and motor disturbances in PD and proposes directions for future research on this topic.



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