A psychometric evaluation of the Arm Motor Ability Test

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Clinical Assessment

Background:

• Stroke significantly impacts upper limb motor function, necessitating reliable assessment tools.
• Existing measures may have limitations in assessing severely impaired populations.
• The Arm Motor Ability Test (AMAT) has been adapted to a 9-item version (AMAT-9) to improve usability.

Purpose of the Study:

• To evaluate the psychometric properties of the 9-item Arm Motor Ability Test (AMAT-9).
• To assess the validity and responsiveness of the AMAT-9 in individuals post-stroke.
• To determine the suitability of the AMAT-9 for individuals with varying degrees of motor impairment.

Main Methods:

• Construct validity was assessed using Rasch analyses on baseline data from 32 individuals post-stroke.
• Correlation analyses were performed with established measures: Wolf Motor Function Test (WMFT), Fugl-Meyer Assessment (FMA), Action Research Arm Test (ARAT), and Stroke Impact Scale (SIS).
• Responsiveness was evaluated using the standardized response mean (SRM) in 29 participants who completed the protocol.

Main Results:

• The AMAT-9 demonstrated strong correlations with the WMFT, FMA, and ARAT (0.78-0.79, p < 0.001).
• Correlation with the SIS Hand Function sub-score was significant (0.40, p = 0.025), while correlation with the Communication sub-score was not (-0.16, p = 0.39).
• Rasch analyses supported the AMAT-9's hierarchical item structure, unidimensionality, and reliability. The SRM was 0.98.

Conclusions:

• The AMAT-9 is a valid and responsive measure for individuals with stroke, especially those with lower scores on the scale.
• Its functional assessment and elimination of the standing item enhance its utility for severely impaired patients.
• The AMAT-9 offers a practical tool for evaluating arm motor ability in stroke rehabilitation.