Reliability of Ultrasound Measurements in Patients with Amyotrophic Lateral Sclerosis
In a study published in the journal Muscle & Nerve, researchers suggest diagnostic ultrasound may provide a reliable biomarker for amyotrophic lateral sclerosis (ALS). This study used ultrasound, performed and evaluated by both a novice and an experienced ultrasonagrapher, to measure the thickness of 4 muscles: the bilateral biceps/brachialis, bilateral hemidiaphragm (at inspiration and expiration), geniohyoid, and bilateral tibialis anterior. Interrater and intrarater correlation coefficients were measured in 10 healthy control subjects and 10 individuals with a diagnosis of ALS. In addition, a novice ultrasonographer took same 9 measurements serially in 10 different individuals with ALS over a 6 month period.
Across the 9 muscle measurements, interrater and correlation coefficients ranged from .80 to .97 for healthy control subjects (n = 10) and .78 to .99 for those with ALS (P < .006 for all measurements). Intrarater correlation coefficients for measurements in healthy control subjects ranged from .83 to .99 (P < .008 for all measurements). The mean percentage decline in muscle thickness over 6 months for patients with ALS (n = 6) was 20.25%.
Together these results suggest that ultrasound may be a useful diagnostic tool for ALS and the authors suggest a larger trial with more sonographers, more subjects, and age-matched controls would be useful for confirming this.