CHAPTER 73: ARM MOTOR ABILITY TEST (AMAT-9)

Description

The Arm Motor Ability Test (AMAT), developed by McCulloch, Cook, Fleming, Novack, and Taub (1988), is a standardized assessment of select activities of daily living (ADLs) that quantify a person’s unilateral or bilateral performance of their upper extremity and, in particular, arm movement. The original AMAT consisted of 16 compound tasks, broken down into categories of 3 movements each that comprise differential contributions from the 2 arms or of the distal and proximal musculature of the affected arm (Kopp et al., 1997) The assessment is generally stroke-specific and has gone through several revisions with the nine item AMAT-9 being the most recent. ADLs on the scale include such items as cutting meat, eating with a spoon, combing hair, opening a jar, tying shoelaces, and using a telephone where some items have multiple components. During assessment the person is scored according to his or her functional performance and the quality of each movement as well as the time to complete each task. The AMAT-9 uses a 6-point ordinal scale (0 to 5) for each item with higher scores indicating better performance. The test takes approximately 40 minutes to complete.

Psychometrics

An initial reliability assessment of the AMAT with 30 subjects at varying periods after a cerebrovascular accident (CVA) and 10 age-matched unaffected controls indicated high inter-rater reliability (range = 0.96 to 0.99, median = 0.97) (McCulloch et al., 1988). A study of 32 community-dwelling stroke survivors found the AMAT-9 to be a reliable measure with a Cronbach’s alpha of α = 0.93, significant correlation with the Action Research Arm Test at 0.79, Fugl-Meyer Assessment (FMA) at 0.79, and the Wolf Motor Function Test at 0.78, suggesting that they have similar constructs as well as testing equivalent phenomenon. The same study found a moderate correlation with the Stroke Impact Scale (hand subscore) at 0.40 as well as a significant negative correlation with the Stroke Impact scale (communication subscore) at –0.16 (O’Dell et al., 2013). A study by Chae, Labatia, and Yang (2003) also found a significant correlation with the FMA (0.94); however, AMAT-9 time of performance exhibited significant ceiling and floor effects and the same study found that it had a negative impact correlation with FMA time at -0.92.

Advantages

The AMAT-9 is unique in that it uses ADLs to test arm motor ability making it specific to occupational therapy practice. There is also a fair amount of research in support of its use in clinical practice. It has also shown to significantly correlate with other more well-known assessments such as the FMA and the Wolf Motor Function test. No special training is required for administration.

Disadvantages

Research by Chae et al. (2003) has suggested that the AMAT quality of movement section is redundant and somewhat based on qualitative observation of the clinician. They also found that the clinical utility of time of performance remains uncertain. The administration of the AMAT can also be longer than other assessments and for more-impaired subjects the test can be tiresome and/or frustrating to complete. A study by Chae et al. (2003) found that the FMA upper extremity arm subtest took less than 5 minutes to complete, whereas the average time to administer the AMAT was approximately 40 minutes.

Administration

The AMAT is composed of 9 bilateral and unilateral ADL-specific tasks. The unilateral activities are performed with the affected arm and the bilateral tasks are performed using (or attempting to use) the dominant or affected limb in the same roles as before onset of the stroke (i.e., tying shoe laces) (Chae et al., 2003). Each task is rated along a 6-point ordinal scale (0 to 5) with respect to functional ability and quality of movement. Each task is also timed, and subjects are given a maximum time limit of 60 or 120 seconds depending on the task (Chae et al., 2003).

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