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

Table 5

AMAT cut scores. Use of AMAT cut scores to discriminate among low, moderate, and high levels of performance across several ICF domains of function.

AMAT			QMA		2MWT (m)		PCS		ADL
Functional level	Score	𝑁	Mean (SD)
1-low	0–24	19	2.48 (±0.70)		58.7 (±24.0)		27.3 (±7.3)		21.0 (±3.0)
2-moderate	25–34	18	3.27 (±0.77)		103.1 (±27.7)		31.5 (±8.3)		26.0 (±3.1)
3-high	35–45	19	5.48 (±1.26)		163.7 (±24.3)		43.9 (±9.81)		30.7 (±3.4)
ANOVA			𝐹 value (all 𝑃 values, <0.001)
			52.9		60.1		18.3		44.7
Tukey’s HSD			𝑃 values
1-2			0.02		0.003		0.341		<0.001
2-3			<0.001		<0.001		<0.001		<0.001
1–3			<0.001		<0.001		<0.001		<0.001

Note: Cut scores are based on the tertiles of the AMAT total score. QMA values have been scaled to body weight.
Abbreviations: AMAT: Adult Myopathy Assessment Tool; ICF: International Classification of Functioning; QMA: quantitative muscle assessment; 2MWT: timed 2 minute walk; (m) meters; PCS: Physical Component Summary (obtained from the Medical Outcomes Study 36-Item Short Form, Version 2); ADL: activities of daily living; (SD) standard deviation; ANOVA: analysis of variance; Tukey’s HSD: Tukey’s Honestly Significant Difference.