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Myotonic dystrophy type 1 alters muscle twitch properties, spinal reflexes, and perturbation‐induced trans‐cortical reflexes
Author(s) -
Shields Richard K.,
Lee Jinhyun,
Buelow Aaron,
Petrie Michael,
DudleyJavoroski Shauna,
Cross Stephen,
Gutmann Laurie,
Nopoulos Peggy C.
Publication year - 2020
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.26767
Subject(s) - reflex , myotonic dystrophy , medicine , myotonia , h reflex , electromyography , central nervous system , dystrophy , neuroscience , physical medicine and rehabilitation , psychology , pathology
Background Neurophysiologic biomarkers are needed for clinical trials of therapies for myotonic dystrophy (DM1). We characterized muscle properties, spinal reflexes (H‐reflexes), and trans‐cortical long‐latency reflexes (LLRs) in a cohort with mild/moderate DM1. Methods Twenty‐four people with DM1 and 25 matched controls underwent assessment of tibial nerve H‐reflexes and soleus muscle twitch properties. Quadriceps LLRs were elicited by delivering an unexpected perturbation during a single‐limb squat (SLS) visuomotor tracking task. Results DM1 was associated with decreased H‐reflex depression. The efficacy of doublet stimulation was enhanced, yielding an elevated double‐single twitch ratio. DM1 participants demonstrated greater error during the SLS task. DM1 individuals with the least‐robust LLR responses showed the greatest loss of spinal H‐reflex depression. Conclusions DM1 is associated with abnormalities of muscle twitch properties. Co‐occurring alterations of spinal and trans‐cortical reflex properties underscore the central nervous system manifestations of this disorder and may assist in gauging efficacy during clinical trials.