Simple Tool Assesses Daily Function in Myositis

Harris-Love MO, Joe G, Davenport TE et al., Reliability of the adult myopathy assessment tool in individuals with myositis.Arthritis Care & Research. (2014) Accepted article.

A simple test that doesn’t require any special equipment and takes only a half hour may help evaluate everyday problems with function, muscle endurance and fatigue among adults with myositis, say researchers at the US Department of Veterans Affairs.

There are currently few validated performance-based tools to measure performance of activities of daily living in myositis, which limits clinical assessment of patients. So the VA undertook an 8-patient pilot study of the Adult Myopathy Assessment Tool (AMAT), a 13-item performance-based battery of tests that can be done in 20-30 minutes in a clinical setting.

The functional subscale of the AMAT includes sit-ups, modified push-ups, arm raises, sit-to-stand movements, and stair-climbing. The endurance subscale looks at muscle stamina during these activities plus knee extensions, head raises and repeated heel raises.

The study finds that the AMAT can not only accurately measure reduced physical performance, but also the impact of excessive fatigue on performance.

The patients, 3 of whom had polymyalgia rheumatica (PM) and 5 who had sporadic inclusion body myositis (sIBM), were given the test individually by physicians in the rehabilitation department at a VA medical center in Washington, DC.

Before administering the test, the physicians had a single AMAT training session. Physical therapists observed the testing by clinicians and both independently scored videotapes of the testing while blinded to the others’ results.

In addition, 19 clinicians – mostly physical therapists at the facility -- scored and re-scored videotapes of 6 myositis patients performing the AMAT.

The VA researchers say the resulting high intra-rater and inter-rater reliability for the AMAT functional subscale, endurance subscale, and total score, show that the battery is suitable for use in a real-world clinical setting.