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Ultrasound a Useful Tool for Detecting Dysphagia in ALS and Other Neurological Diseases
Ultrasonography is an effective and convenient method for evaluating common swallowing disorders, like dysphagia, that are common in neurological diseases including amyotrophic lateral sclerosis (ALS). Findings from a systematic review examining the utilization of ultrasound (US) to assess swallowing disorders were published in the journal Dysphagia.
“Because there is a wide variety of ultrasound systems and transducers, the clinician needs to be trained to correctly utilize each system. Ultrasound is a low-cost, portable, non-invasive tool that can use any food material in a swallowing study,” noted lead author Paola Potente, LM, Clinical Unit of Neurology, University Hospital of Trieste ASUGI, University of Trieste, Italy, and co-authors in the study conclusion. “Speech language pathologists can be easily trained to use this technique for clinical evaluations and rehabilitation of neurologic dysphagia.”
While US has been the subject of previous studies to examine its utility in assessing swallowing impairments, there is a “lack of common consensus and specific guidelines” on how to conduct those evaluations. Consequently, researchers reviewed the existing literature to determine how useful US might be for measuring neurogenic dysphagia.
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The systematic review included 10 studies encompassing 292 patients with a neurological disease diagnosis: 181 with stroke, 47 with Parkinson disease, 46 with muscular dystrophies, and 18 with ALS. US measurements were taken to assess tongue, facial, and suprahyoid muscle thickness and echogenicity, and to assess hyoid displacement features.
In the ALS study, the 18 patients were compared with 18 matched healthy controls. US examination was performed using a 3.5 MHz convex array transducer to assess fasciculation. Tongue thickness, or the distance between the upper and lower surfaces of the lingual muscles, of ALS patients was significantly lower than in the control group (p=0.016), which may indicate tongue muscle atrophy. Tongue thickness was also significantly associated with BMI in the ALS group (p=0.003). The ALS group also showed a significant decrease in tongue thickness over the course of the disease (p=0.002), an indicator that aligns with atrophy in bulbar muscles. Overall, US results were an advantageous tool for diagnosing tongue muscle fasciculation for this population
“US is able to detect structural changes caused by dystrophy or denervation of muscles, detect involuntary movements such as fasciculations, and provide dynamic video images of tongue motion during swallowing attempts. Hence, US should be used when evaluating swallowing in neurological disorders,” said Potente and co-authors.
The researchers noted some potential disadvantages to US, including transducer positioning and the lack of precise anatomical markers that may skew the outcome.
“Future studies should aim to propose standard and common protocols to test neurogenic dysphagia with US, and to suggest normative values to help identify pathologically and at-risk conditions,” the authors concluded.
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