Robotic assessment of the influence of age on upper-limb sensorimotor function

Abstract

Purpose

This paper examines the influence of age on several attributes of sensorimotor performance while performing a reaching task. Our hypothesis, based on previous studies, is that aged persons will show differences in one or more of the attributes of sensorimotor performance.

Patients and methods

Fifty-one subjects (aged 20–80 years) with no known neuromotor disorders of the upper limbs participated in the study. Subjects were asked to grasp the end-effector of a pneumatic robotic device with two degrees of freedom in order to reach peripheral targets (1.0 cm radius), “quickly and accurately”, from a centrally located target (1.0 cm radius). Subjects began each trial by holding the hand within the central target for 2000 milliseconds. Afterwards, a peripheral target was illuminated. Then participants were given 3000 milliseconds to complete the movement. When a target was reached, the participant had to return to the central target in order to start a new trial. A total of 64 trials were completed and each peripheral target was illuminated in a random block design.

Results

Subjects were divided into three groups according to age: group 1 (age 20–40 years), group 2 (age 41–60 years), and group 3 (age 61–80 years). The Kruskal–Wallis test showed significant differences (P < 0.05) between groups, except for the variables postural speed in the dominant arm, and postural speed and initial deviation in the non-dominant arm (P > 0.05). These results suggest that age introduces significant differences in upper-limb motor function.

Conclusion

Our findings show that there are objective differences in sensorimotor function due to age, and that these differences are greater for the dominant arm. Therefore for the assessment of upper-limb function, we should take into account the influence of age. Moreover, these results suggest that robotic systems can provide a new and effective approach in the assessment of sensorimotor function.

Keywords:

• aging
• sensorimotor function
• robotics
• rehabilitation

Acknowledgments

This work was partly supported by the European Commission (FP7-ECHORD MAAT experiment) and by the Spanish Government through the project “Interpretation of the human intention and performance through biomedical signals and analysis of kinematic and dynamic motion” (DPI2011-29660-C04-04). AL carried out the study, the statistical analyses and drafted the manuscript; FJ contributed to data acquisition, analysis and drafting the manuscript; RM contributed to modifying the control system and software application of the robotic device to fit with the requirements of the study and drafting the manuscript; NG contributed to data analysis and interpretation and drafting of the manuscript; JM contributed to data acquisition, data analysis, data interpretation and drafting the manuscript; EF conceived the study and participated in its design and coordination and helped draft the manuscript. All authors read and approved the final manuscript.

Disclosure

The authors report no conflicts of interest in this work.