On Understanding and Measuring the Cognitive Load of Amputees for Rehabilitation and Prosthetic Development

Abstract

Objective: To derive a definition of cognitive load that is applicable for amputation as well as analyze suitable research models for measuring cognitive load during prosthetic use. Defining cognitive load for amputation will improve rehabilitation methods and enable better prosthetic design. Data Sources: Elsevier, Springer, PLoS, IEEE Xplore, PubMed. Study Selection: Studies on upper-limb myoelectric prosthetics and neuroprosthetics were prioritized. For understanding measurement, lower-limb amputations and studies with healthy individuals were included. Data Extraction: Queries including ‘cognitive load’, ‘neural fatigue’, ‘brain plasticity’, ‘neuroprosthetics’, ‘upper-limb prosthetics’, and ‘amputation’ were used with peerreviewed journals or articles. Papers published within the last 6 years were prioritized. Articles on foundational principles were included regardless of date. A total of 69 articles were found: 12-amputation, 15-cognitive load, 8-phantom limb, 22-sensory feedback, 12- measurement methods. Data Synthesis: The emotional, physiological, and neurological aspects of amputation, prosthetic use, and rehabilitation aspects of cognitive load were analyzed in conjunction with measurement methods, including resolution, invasiveness, and sensitivity to user movement and environmental noise. Conclusions: Usage of ‘cognitive load’ remains consistent with its original definition. For amputation, two additional elements are needed: ‘emotional fatigue’, defined as an amputee’s emotional response, including mental concentration and emotions, and ‘neural fatigue’, the physiological and neurological effects of amputation on brain plasticity. Cognitive load is estimated via neuroimaging techniques, including EEG, fMRI, and fNIRS. Because fNIRS measures cognitive load directly, has good temporal and spatial resolution, and is not as restricted by user movement, fNIRS is recommended for most cognitive load studies.