Teaching Video NeuroImages: Trapezius myotonia percussion sign in myotonic dystrophy type 2
Associated Data
Abstract
Myotonic dystrophy type 2 (DM2) is an autosomal dominant disorder with proximal weakness, muscle pain, and early-onset cataracts.1 In comparison with myotonic dystrophy type 1 (DM1), myotonia is less symptomatic, more proximal, and harder to detect during clinical and electrodiagnostic testing.2 Here we document the presence of trapezius myotonia in patients with DM2 (video on the Neurology® Web site at www.neurology.org). In our experience, similar proximal percussion does not produce as marked a response in DM1 or nondystrophic myotonic disorders. This sign demonstrates a mechanism to test for proximal myotonia, and in at-risk patients, may be suggestive of an underlying diagnosis of DM2.
Myotonic dystrophy type 2 (DM2) is an autosomal dominant disorder with proximal weakness, muscle pain, and early-onset cataracts.1 In comparison with myotonic dystrophy type 1 (DM1), myotonia is less symptomatic, more proximal, and harder to detect during clinical and electrodiagnostic testing.2 Here we document the presence of trapezius myotonia in patients with DM2 (video on the Neurology® Web site at www.neurology.org). In our experience, similar proximal percussion does not produce as marked a response in DM1 or nondystrophic myotonic disorders. This sign demonstrates a mechanism to test for proximal myotonia, and in at-risk patients may be suggestive of an underlying diagnosis of DM2.
Footnotes
Supplemental data at www.neurology.org
AUTHOR CONTRIBUTIONS
Nicholas E. Johnson: drafting manuscript, data collection. Chad R. Heatwole: revision of manuscript, design of project.
STUDY FUNDING
No targeted funding reported.
DISCLOSURE
N. Johnson reports no disclosures. C. Heatwole receives support through the National Institute of Arthritis and Musculoskeletal and Skin Disorders (1K23AR055947). Go to Neurology.org for full disclosures.

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