Reliability of the Thickness Measurement and Histogram of Elbow Flexors by Ultrasonography in Patients with Fascioscapulohumoral Dystrophy and Healthy Subjects

Abstract

Introduction: Ultrasonography is a non-invasive and available technique used to assess normal and pathological tissue in people with neuromuscular diseases. The aim of this study was to determine relative and absolute reliability of ultrasonography in evaluation of thickness and histogram of elbow flexor muscles in patients with facioscapulohumeral muscular dystrophy (FSHD and healthy subjects. Materials and Methods: The present study was carried out on an experimental group of six patients with FSHD and a control group comprising 6 healthy individuals. The thickness and histogram of elbow flexors were evaluated while subjects were in sitting position with knees bent, arms at 90 degrees abduction, elbows at 90 degrees flexion and forearms in neutral position. The probe was placed on the anterior surface of arm at 2/3 distance between the lateral tip of acromion and the lateral epicondyle of the humerus. Standard deviation of echogenicity based on histogram curve was also used to estimate the echogenic uniformity of muscle tissue (STDE), subsequently two parameters including L-mean and STDE were recorded. The intra-class correlation coefficient (ICC), standard error measurement (SEM) and minimal detectable changes (MDC) tests were applied to measure relative and absolute reliability and to estimate the measurement errors. Results: The values of the reliability of muscle thickness measurement were ICC=0.95, SEM=2.14 and MDC=5.94 and ICC=0.95, SEM=1.34 and MDC=3.72 in the experimental group and the control group respectively. Additionally, for L-mean measurements it appeared to be ICC=0.89, SEM=1.75 and MDC=4.86 among patients and ICC=0.66, SEM=1.04 and MDC=2.89 in healthy subjects. Finally, the reliability of STDE measurement was revealed to be ICC=0.98, SEM=0.18 and MDC=0.51 and (ICC=0.75, SEM=0.63 and MDC=1.74) among the participants of the experimental and the control groups. Conclusion: The results of this study showed that ultrasonography method used in this study had a high level of accuracy to measure the thickness and histogram of elbow flexors in both healthy subjects and patients with FSHD. The method can be recommended to compare or determine the effectiveness of different treatment methods in patients with FSHD. Key words: Elbow Flexors, Fascioscapulohumoral Dystrophy Histogram, Reliability; Thickness, Ultrasonography