A tool for measuring mental workload during prosthesis use: The Prosthesis Task Load Index (PROS-TLX).

Area of Science:

• Rehabilitation Engineering
• Human-Computer Interaction
• Prosthetics and Orthotics

Background:

• Upper-limb prosthesis use involves significant mental, emotional, and physical effort, often leading to dissatisfaction and rejection.
• Quantifying this workload is crucial for improving prosthetic device design and user support.
• Existing workload measures may not fully capture the unique demands of prosthetic limb use.

Purpose of the Study:

• To design and validate a self-report measure, the Prosthesis Task Load Index (PROS-TLX), for quantifying mental workload in upper-limb prosthesis users.
• To identify and confirm key workload constructs relevant to the prosthetic limb experience.
• To assess the validity of the PROS-TLX during the initial learning phase of prosthesis use.

Main Methods:

• Surveyed upper-limb prosthesis users to identify and confirm eight critical workload constructs.
• Validated the PROS-TLX by comparing able-bodied participants' performance using a prosthesis simulator versus their anatomical hand on a coin-placement task.
• Utilized eye-tracking equipment to measure visual fixation during the task.

Main Results:

• The PROS-TLX successfully encapsulated mental, physical, and emotional demands reported by users.
• Prosthesis simulator use led to slower movements, increased errors, and heightened visual attention to the hand compared to anatomical hand use.
• Performance decrements correlated with significant increases in PROS-TLX subscale scores, demonstrating good convergent and divergent validity.

Conclusions:

• The developed PROS-TLX is a promising tool for assessing the multifaceted workload associated with upper-limb prosthesis use.
• The findings highlight the significant performance and cognitive demands during initial prosthesis learning.
• Further validation is needed to confirm the PROS-TLX's clinical utility for real-world prosthetic users.