Effect on hand kinematics when using assistive devices during activities of daily living

Abstract

Assistive devices (ADs) are products intended to overcome the difficulties produced by the reduction in mobility and grip strength entailed by ageing and different pathologies. Nevertheless, there is little information about the effect that the use of these devices produces on hand kinematics. Thus, the aim of this work is to quantify this effect through the comparison of kinematic parameters (mean posture, ROM, median velocity and peak velocity) while performing activities of daily living (ADL) using normal products and ADs. Twelve healthy right-handed subjects performed 11 ADL with normal products and with 17 ADs wearing an instrumented glove on their right hand, 16 joint angles being recorded. ADs significantly affected hand kinematics, although the joints affected differed according to the AD. Furthermore, some pattern effects were identified depending on the characteristics of the handle of the ADs, namely, handle thickening, addition of a handle to products that initially did not have one, extension of existing handles or addition of handles to apply higher torques. An overview of the effects of these design characteristics on hand kinematics is presented as a basis for the selection of the most suitable AD depending on the patient's impairments.

Keywords: Activities of daily living; Assistive device; Hand kinematics; Hand posture; Instrumented glove.

Conflict of interest statement

The authors declare there are no competing interests.

©2019 Roda-Sales et al.

Figures

Figure 1. Products used during the performance of the ADL (tasks (A) T1 to (K) T11) considered in the experiment.

The labels A1, A2 and A3 refer to the different assistive devices used for the task; the label N refers to the normal product.

Figure 2. Subject wearing the instrumented glove performing the task of eating with a spoon.

Figure 3. Mean values of the mean angle (deg) obtained for each joint, task ((A) T1 to (K) T11) and product.

Joints with significant differences for all the ADs are underlined. Joints with significant differences for some ADs are underlined and marked with an asterisk of the corresponding colour. Tasks and products labelled as described in Table 1 and Fig. 1. Joints labelled as described in main text. Positive values for flexion, abduction of fingers and palmar deviation of thumb.

Figure 4. Mean values of the ROM (deg) obtained for each joint, task ((A) T1 to (K) T11) and product.

Joints with significant differences for all the ADs are underlined. Joints with significant differences for some ADs are underlined and marked with an asterisk of the corresponding colour. Tasks, products and joints labelled as described in Fig. 3.

Figure 5. Mean of the median velocity (deg/s) obtained for each joint, task ((A) T1 to (K) T11) and product.

Joints with significant differences for all the ADs are underlined. Joints with significant differences for some ADs are underlined and marked with an asterisk of the corresponding colour. Tasks, products and joints labelled as described in Fig. 3.

Figure 6. Mean values of the percentile P95 values of velocities (deg/s) obtained for each joint, task ((A) T1 to (K) T11) and product.

Joints with significant differences for all the ADs are underlined. Joints with significant differences for some ADs are underlined and marked with an asterisk of the corresponding colour. Tasks, products and joints labelled as described in Fig. 3.

Figure 7. Box-plots of time of accomplishment of the tasks when performed with the different products.

Tasks and products labelled as described in Table 1 and Fig. 1.

Figure 8. AD design characteristics and global results obtained across the different studies.