Development and validation of the coffee task: a novel functional assessment for prosthetic grip selection

Area of Science:

• Biomedical Engineering
• Rehabilitation Science
• Prosthetics and Orthotics

Background:

• Lack of standardized assessments hinders evaluation of multi-grip prosthetic hand designs and control strategies.
• Quantifying prosthetic grip selection performance is crucial for validating design improvements.

Purpose of the Study:

• To develop and validate a novel assessment, the Coffee Task, for evaluating multi-grip prosthetic performance.
• To establish the reliability, validity, and responsiveness of the Coffee Task.

Main Methods:

• Developed and validated the Continuous and Segmented Coffee Task for myoelectric prosthetic emulator use.
• Assessed inter-rater reliability, known-group validity (emulator vs. intact limb), and convergent validity (vs. Box and Block Test).
• Evaluated responsiveness to practice and control approach using standardized response mean (SRM).

Main Results:

• High inter-rater reliability for both Coffee Task versions (ICC > 0.981).
• Moderate correlation between Coffee Task and Box and Block Test outcomes (|r| ≥ 0.412).
• The task was responsive to practice (SRM ≥ 0.81) but not control approach (SRM ≤ 0.12).

Conclusions:

• The Coffee Task demonstrates reliability, known-group validity, convergent validity, and responsiveness to practice.
• This novel assessment provides a valuable tool for evaluating prosthetic grip selection.
• Future research should focus on the feasibility and reliability of the Coffee Task for individuals with upper limb loss.