Abstract:
Objectives: The present study aimed to investigate the possible effects of laterality
and handedness on higher-order sensory functions and manual dexterity of the
elderly.
Methods: In this non-experimental cross-sectional study, 58 elderly people aged
60-75 years (35 right-handed) were recruited through a convenience sampling
method. Laterality of the selected subjects was examined using the Edinburg test,
while the higher-order sensory functions were assessed via haptic performance
along with weight and texture discrimination tests. Gross and fine manual dexterity
functions were assessed with the help of the box-and-block and Purdue pegboard
tests, respectively.
Results: Results showed that the main effects of laterality and handedness, as well
as the interaction effect of laterality × handedness on the haptic performance of the
elderly were not significant. However, the main and interaction effects of laterality
and handedness on the texture and weight discrimination of the elderly were
significant. On the other hand, the main and interaction effects of laterality and
handedness on the gross and fine manual dexterity of the elderly were not found to
be significant.
Discussion: Laterality has no effect on the higher-order sensory functions of rightand
left-handed elderly people. However, effects of laterality on fine motor dexterity
in right-handed individuals were detected.
Machine summary:
Interestingly, it has al- ready been shown that the difference in sensory-motor functions between the dominant and non-dominant hand is completely dependent on the task performed as well as the age and laterality of the individual [5, 6].
No study has ever reported the difference in high-order sensory functions (haptic performance, weight and texture discrimination) between the domi- nant and non-dominant hands of right- and left-handed elderly individuals.
Therefore, the present study was designed to compare weight and texture discrimination, haptic performance as well as fine and gross manual dexterity between the dominant and non-dominant hand of right- and left- handed elderly individuals.
The results of the Shapiro-Wilks test showed that senso- ry-motor functions using the dominant or non-dominant hand were normally distributed in right- and left-handed elderly individuals for all assessments.
Based on these results, it was concluded that the gross manual dexterity function of the dominant and non-dominant hand is not significantly different between the right and left-handed groups (Figure 1E).
4. Discussion The results of the study indicated that the HORT and HAST did not present significant differences between the higher-order sensory functions of the dominant and non- dominant hand in both right and left-handed subjects.
Based on the HAROLD model, asymmetry in complex tasks decreases as age increases, thereby pro- viding results that show lack of significant differences in the functions of the dominant and non-dominant hand of right- and left-handed groups.
This study also showed that there are no significant differences in the motor functions of the dominant and non-dominant hands of right- and left-handed elderly in- dividuals.