Impaired finger dexterity in patients with parkinson's disease correlates with discriminative cutaneous sensory dysfunction

Abstract

To study the influence of discriminative cutaneous sensory dysfunction on impaired finger dexterity in Parkinson's disease (PD), we evaluated 48 right-handed PD patients during a practically defined off-medication period and 24 healthy age-matched controls. With visual deprivation, a finger tapping task (FTT) was performed to assess the speed of simple repetitive finger movements and a coin rotation task (CRT) was used to assess finger dexterity. The tasks were performed with the right hand. We measured the somesthetic temporal discrimination threshold (sTDT) in the right index finger. The mean ± SD FTT score of the patient group was lower than that of the control group (24.0 ± 8.0 vs. 29.8 ± 7.8; P < 0.01). The patient group performed worse on the CRT than the control group (8.5 ± 3.5 vs. 12.6 ± 1.7; P < 0.001). The mean sTDT value of the patient group was longer than that of the control group (124.0 ± 44.8 vs. 78.1 ± 26.2 ms; P < 0.001). The CRT scores correlated with the sTDT values (Pearson's correlation coefficient = -0.43; P < 0.01), but not with the Unified Parkinson's Disease Rating Scale (UPDRS) finger bradykinesia scores or FTT scores. Multiple regression analysis showed that the sTDT values (parameter estimate = -0.03, SE = 0.01; P < 0.01), but not patient age, UPDRS finger bradykinesia score, or FTT score, affected the CRT score. Slowness of simple repetitive finger movements did not have a strong impact on the impaired manual dexterity of PD. Discriminative sensory dysfunction and consequent abnormal sensorimotor integration seem to be involved in the impaired finger dexterity of PD.

Dopamine Alters Tactile Perception in Parkinson's Disease

“…The present study compared TOJ with and without synchronization in PD patients in the on and off medication states and healthy controls. We hypothesized that TOJ thresholds would be higher in PD versus controls similar to the observations made for TDT measures 8,9,20 . Owing to the perceptual improvements associated with dopaminergic medications, we further predicted that TOJ would be improved in the 'on' versus the 'off' states in PD with and without synchronization stimuli.…”

Point pressure sensitivity in early stage Parkinson's disease

“…While declines in olfactory and visual function are well documented in PD [3,4], deficits in other sensory systems are less so, and most studies have evaluated medicated PD patients of relatively advanced stage. In the case of somatosensation, PD-related decrements in spatial discrimination [5,6], temporal processing [7,8], and haptic perception [9,10] are reasonably well established. However, this is not the case for point pressure sensitivity (PPS), a measure of myelinated Aβ fiber function mediated through Merkel and Meissner mechanoreceptors [11][12][13].…”

Impact of Prolonged Temporal Discrimination Threshold on Finger Movements of Parkinson’s Disease

“…Therefore, prolonged TDT in PD patients may have an impact on parkinsonian motor deficits. Indeed, such prolongation in the index finger of PD patients has a significant impact on the dexterity of finger movements [5]. …”