Correlation between lower and higher order sensory functions and manual dexterity in dominant and non-dominant hand of patients with idiopathic Parkinson's disease

Objective: To investigate the correlation between lower and higher order sensory functions and manual dexterity as well as to identify the sensory measures that could predict manual dexterity in patients with idiopathic Parkinson’s disease (PD). Materials and methods: In this cross-sectional study, 55 patients with idiopathic PD by mean age of 59.85 ± 11.89 years, and mean Hoehn and Yahr stage of 2.76 ± 1.37 were non-randomly selected. Lower order sensory function (i.e., light touch threshold), higher order sensory functions (i.e., tactile acuity, weight and texture discrimination, haptic performance and wrist proprioception) as well as gross and fine manual dexterity were measured in both hands. Results: The results showed that light touch threshold and tactile acuity (measured by static two point discrimination (TPD) were not significantly associated with gross or fine manual dexterity in dominant or non-dominant hand. Tactile acuity (measured by moving TPD), weight discrimination and wrist proprioception were weakly correlated with gross and fine manual dexterity in both hands. A weak to moderate significant relation was found between texture discrimination and haptic performance and both type of manual dexterity in both hands. Haptic performance predicted the largest proportion of variance in the gross manual dexterity of both hands as well as fine manual dexterity of dominant hand.Conclusion: This study showed the low to moderate correlation between higher order sensory functions and manual dexterity in patients with idiopathic PD. Haptic performance seems to be the most influential higher order sensory function associated with manual dexterity in these patients.