Assessing Function and Endurance in Adults with Spinal and Bulbar Muscular Atrophy: Validity of the Adult Myopathy Assessment Tool

Abstract

Purpose. The adult myopathy assessment tool (AMAT) is a performance-based battery comprised of functional and endurance subscales that can be completed in approximately 30 minutes without the use of specialized equipment. The purpose of this study was to determine the construct validity and internal consistency of the AMAT with a sample of adults with spinal and bulbar muscular atrophy (SBMA). Methods. AMAT validity was assessed in 56-male participants with genetically confirmed SBMA (mean age, 53 ± 10 years). The participants completed the AMAT and assessments for disease status, strength, and functional status. Results. Lower AMAT scores were associated with longer disease duration (r = −0.29; P < 0.03) and lower serum androgen levels (r = 0.49–0.59; P < 0.001). The AMAT was significantly correlated with strength and functional status (r = 0.82–0.88; P < 0.001). The domains of the AMAT exhibited good internal consistency (Cronbach's α = 0.77–0.89; P < 0.001). Conclusions. The AMAT is a standardized, performance-based tool that may be used to assess functional limitations and muscle endurance. The AMAT has good internal consistency, and the construct validity of the AMAT is supported by its significant associations with hormonal, strength, and functional characteristics of adults with SBMA. This trial is registered with Clinicaltrials.gov identifier NCT00303446.

Plasma pNfH differentiate SBMA from ALS

“…This data supports the recent hypothesis of a primary muscle origin of damage in SBMA patients 2,4,13,14 and is consistent with results of NfL in SBMA 14 .…”

“…Clinical assessment SBMA patients had a genetical confirm of diagnosis, while ALS patients had a diagnosis of definite or probable ALS according to the revised El-Escorial criteria 10 . Disease severity was assessed using ALSFRSr 11 , SBMA Functional-Rating-Scale (SBMAFRS) 12 and Adult-Myositis-Assessment-Tool (AMAT) 13 scale in SBMA patients and using ALSFRS-r scale in ALS patients. Demographic and clinical data of patients are gathered in Table 1.…”

Clinical Assessment of Fatigability in Multiple Sclerosis: A Shift from Perception to Performance

“…Current functional exams of performance in MS are not strongly associated with fatigue as a trait characteristic (20–22). Tests which may hold promise include the Short Physical Performance Battery Protocol (28), Adult Myopathy Assessment Tool (29), and the Functional Capacity Test developed by Dalgas et al (30). These tests attempt to combine various repetitive tasks which mimic daily function.…”

Reliability of the Adult Myopathy Assessment Tool in Individuals With Myositis

“…The AMAT was later adopted by investigators seeking performance-based measures of functional performance appropriate for individuals with rare myopathies. Our recent findings indicate that the AMAT has moderate to good internal consistency, construct validity, and responsiveness, and also features cut scores that exhibit discriminative validity in individuals with neuromuscular disease [19,27]. In addition, we conducted pilot work involving 8 participants with myositis (age 62.6 ±10.4 years of age, 6 males, 2 females, 3 with PM and 5 with sIBM) early in the AMAT’s development to assess interrater reliability.…”