Using Rasch Analysis to Validate the Motor Activity Log and the Lower Functioning Motor Activity Log in Patients With Stroke
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I-Ching Chuang1, Keh-Chung Lin2,3, Ching-Yi Wu1,4
1Department of Occupational Therapy and Graduate Institute of Behavioral Sciences, College of Medicine, Chang Guang University.
Background:
The Motor Activity Log (MAL) and Lower-Functioning MAL (LF-MAL) are used to assess the amount of use of the more impaired arm and the quality of movement during activities in real-life situations for patients with stroke.
Objective:
This study used Rasch analysis to examine the psychometric properties of the MAL and LF-MAL in patients with stroke.
Design:
This is a methodological study.
Methods:
The MAL and LF-MAL include 2 scales: the amount of use (AOU) and the quality of movement (QOM). Rasch analysis was used to examine the unidimensionality, item difficulty hierarchy, targeting, reliability, and differential item functioning (DIF) of the MAL and LF-MAL.
Results:
A total of 403 patients with mild or moderate stroke completed the MAL, and 134 patients with moderate/severe stroke finished the LF-MAL. Evidence of disordered thresholds and poor model fit were found both in the MAL and LF-MAL. After the rating categories were collapsed and misfit items were deleted, all items of the revised MAL and LF-MAL exhibited ordering and constituted unidimensional constructs. The person-item map showed that these assessments were difficult for our participants. The person reliability coefficients of these assessments ranged from .79 to .87. No items in the revised MAL and LF-MAL exhibited bias related to patients' characteristics.
Limitations:
One limitation is the recruited patients, who have relatively high-functioning ability in the LF-MAL.
Conclusions:
The revised MAL and LF-MAL are unidimensional scales and have good reliability. The categories function well, and responses to all items in these assessments are not biased by patients' characteristics. However, the revised MAL and LF-MAL both showed floor effect. Further study might add easy items for assessing the performance of activity in real-life situations for patients with stroke.