Use of Muscle Ultrasonography in Morphofunctional Assessment of Amyotrophic Lateral Sclerosis (ALS)

Abstract

Amyotrophic lateral sclerosis (ALS) is a progressive disease with a high prevalence of malnutrition that can influence prognosis. The main objective of this study is to compare the validity of muscle ultrasonography in the diagnosis of malnutrition and the prognosis of patients with ALS. METHODS: This is a prospective observational study that analyzes the nutritional status of patients at the beginning of nutritional monitoring. The morphofunctional assessment included the examination of anthropometric variables such as weight, height, body mass index (BMI), arm circumference, and calf circumference. Additionally, electrical bioimpedanciometry (BIA) was used to measure electrical parameters and estimate other relevant metrics. Muscle ultrasonography® (quadriceps rectus femoris (QRF)) assessed muscle mass parameters, including muscle area index (MARAI), anteroposterior diameter of the QRF (Y-axis) (cm), transverse diameter of the QRF (X-axis) (cm), and the sum of the quadriceps thickness (RF+VI) (cm), as well as muscle quality parameters such as echogenicity and the Y-X index. RESULTS: A total of 37 patients diagnosed with amyotrophic lateral sclerosis (ALS) were included in this study. Of these patients, 51.4% were men. The mean age was 64.27 (12.59) years. A total of 54.1% of the patients had a bulbar onset of amyotrophic lateral sclerosis, and 45.9% had spinal onset. The percentage of subjects with malnutrition diagnosed by the Global Leadership Initiative on Malnutrition (GLIM) criteria was 45.9% of patients. There was a direct correlation between muscle mass parameters assessed by muscle ultrasonography (RF+VI) and active mass markers measured by bioimpedanciometry (body cellular mass index (BCMI) (r = 0.62; p < 0.01), fat-free mass index (FFMI) (r = 0.75; p < 0.01), and appendicular skeletal mass index (ASMI) (r = 0.69; p < 0.01)). There was a direct correlation between echogenicity and resistance (r = 0.44; p = 0.02), as well as between the fat-free mass index and the Y-X index (r = 0.36; p = 0.14). Additionally, there was a negative correlation between echogenicity and BCMI (r = -0.46; p < 0.01) and ASMI (r = 0.34; p = 0.06). Patients with low quadriceps thickness (male < 2.49 cm; female < 1.84 cm) showed an increased risk of hospital admission adjusted by age, sex, and presence of dysphagia (OR: 7.84 (CI 95%: 1.09-56.07); p-value = 0.04), and patients with low-quality mass (Y-X index < 0.35) had a higher risk of hospital admission adjusted by age, sex, and presence of dysphagia (OR: 19.83 (CI 95%: 1.77-222.46); p-value = 0.02). CONCLUSIONS: In patients with ALS, ultrasonography echogenicity was inversely related to BCMI, FFMI, and ASMI, and the Y-X index was directly related to FFMI. The lowest quartiles of quadriceps thickness and Y-X index are risk factors for hospital admission.