Ultrasound Is a Reliable Measure of Muscle Thickness in Acute Stroke Patients, for Some, but Not All Anatomical Sites: A Study of the Intra-Rater Reliability of Muscle Thickness Measures in Acute Stroke Patients

This prospective, blinded study investigates the test retest reliability of measures of muscle thickness made by one sonographer across two cohort groups (n = 29) of people hospitalised with acute stroke. Reliability was assessed in cohort one (n = 14) for measurements made bilaterally at the anterior and posterior upper arms, the anterior and posterior thighs (total of eight measurements) and in cohort two (n = 15), for measurements made bilaterally at the lateral forearms, the anterior abdominal wall and the anterior and lower legs (total of eight measurements). Reliability estimates varied between measurement sites; intraclass correlation coefficients (ICCs) ranged from -0.26 (lateral forearm, paretic side) to 0.95 (anterior thigh, nonparetic side), percent mean differences ranged from 0.42% (posterior upper arm, nonparetic side) to 14.68% (anterior lower limb, nonparetic side) and method error ranged from 1.08 (abdomen, nonparetic side) to 9.69 mm (posterior lower limb, nonparetic side). Only four measurement sites (anterior upper arm, posterior upper arm, abdomen and anterior thigh) were within the acceptable ranges (ICC 0.60 to 1.00, mean percent difference range 0%-5% and method error range 0-5 mm) and considered reliable to use for measures of muscle thickness in people hospitalised with acute stroke.