Facioscapulohumeral muscular dystrophy (FSHD) is a hereditary muscle disorder. One of its most distinct symptoms is facial weakness, which can lead to diminished facial expression. This can significantly impact the psychosocial wellbeing of those affected. Despite its importance, research on facial weakness in FSHD is limited, and effective imaging techniques for assessing facial muscles are lacking.
PhD candidate and neurology resident Sanne Vincenten investigated the potential of using facial muscle ultrasound in a large cohort of FSHD patients. Her study aimed to assess the reliability of this imaging method and to characterize facial muscle involvement in FSHD. The research group, led by Nens van Alfen and Karlien Mul from the department of Neurology, published the results in Muscle & Nerve on the 8th of October 2024.
The study involved 107 participants with FSHD, who were clinically evaluated before undergoing the facial muscle ultrasound protocol that included nine orofacial muscles. All obtained ultrasound images were evaluated visually, using a semi-quantitative scale, and quantitatively, using grayscale levels. While the visual analysis of the images showed a wide range of reliability, the quantitative analyses proved to be highly consistent. The quantitative results showed that the muscles responsible for facial expression were affected most frequently, with 15 to 39% of the participants showing signs of involvement. In contrast, the muscles involved in chewing and swallowing were rarely affected (<5%). The additionally calculated ultrasound compound score correlated weakly to moderately to the clinical measures used.
Their findings add to our understanding of orofacial weakness in FSHD and demonstrate that muscle ultrasound can be a reliable tool for assessing facial muscles quantitatively. However, further longitudinal studies are needed to track the progression of facial weakness in FSHD over time, and to track changes in the facial muscle ultrasound abnormalities we found. The research group is currently analyzing the data from a 1.5-year follow-up study and they anticipate providing answers to these remaining questions soon.
About the publication
Vincenten SCC, van Doorn JLM, Teeselink S, Rasing NB, Padberg GW, Voermans NC, van Engelen BGM, van Alfen N, Mul K. The other face of facioscapulohumeral muscular dystrophy: Exploring orofacial weakness using muscle ultrasound. Muscle Nerve. 2024 Sep 19. doi: 10.1002/mus.28254. Epub ahead of print. PMID: 39297366.