Rubin, Devon I.

Introduction: Nusinersen antisense oligonucleotide infusions have been shown to be effective in the treatment spinal muscular atrophy. The majority of the evidence has been collected in young type 1 and type 2 patients, and evidence of efficacy in adult patients is limited. Case Report: A 48-year-old woman with spinal muscular atrophy type 3 who has received the loading dose and 8 maintenance infusions over an 8-month period. Grip and pinch strength, measured by hand-held dynamometry measured at baseline and in 6 to 12 months interval improved over a 24-month period. She also reported multiple other subjective improvements in function. Conclusions: This is the first published case of nusinersen in a middle-aged adult with spinal muscular atrophy. Sustained clinically meaningful improvement may be possible with nusinersen initiation in mid adulthood.

AbstractIntroductionThe sensitivity of repetitive nerve stimulation (RNS) in myasthenia gravis (MG) is dependent on the cutoff for abnormal decrement.MethodsRNS data of adults with and without MG from 2014 to 2017 were reviewed retrospectively. The maximum reliable RNS amplitude/area decrement before and after exercise from facial, spinal accessory (SA), ulnar, and fibular nerves was recorded. Sensitivity/specificity using 5%, 7%, and 10% cutoffs were calculated.ResultsSeventy‐nine of 141 patients had MG (46 generalized, 21 ocular, 12 bulbar). A total of 608 unique RNS recordings were analyzed. Overall RNS sensitivity/specificity at ≥5%, ≥7%, and ≥10% amplitude cutoffs were as follows: SA, 65.6%/86.3%, 49.2%/94.1%, and 29.5%/96.1%; facial, 51.0%/82.5%, 43.1%/95.0%, and 37.3%/100%; ulnar, 43.6%/100%, 41.0%/100%, and 41.0%/100%; and fibular, 52.6%/89.5%, 42.1%/94.7%, and 42.1%/100%.DiscussionLowering amplitude cutoff from 10% to 7% increased or maintained sensitivity with little loss in specificity. Post‐exercise and area analysis resulted in increased sensitivity in some circumstances.

ABSTRACT Introduction Needle electromyography (EMG) findings help confirm myopathy and may indicate specific pathologic changes on muscle biopsy. Methods We conducted a retrospective chart review of 218 consecutive patients referred for muscle biopsy. Presence of specific needle EMG findings was correlated with pathologic findings of inflammation, necrosis, splitting, and vacuolar changes. Sensitivity, specificity, and positive and negative predictive values of specific EMG findings for pathologic changes were calculated. Results Short‐duration motor unit potentials (MUP) were sensitive (83%–94%) but not specific (34%–49%) for pathologic changes. Fibrillation potentials were 65%–74% sensitive and 58%–81% specific for inflammation, necrosis, splitting, or vacuolar changes. The absence of fibrillation potentials had high negative predictive value (82%–93%) for inflammation, splitting, or vacuolar changes. Discussion Fibrillation potentials and short‐duration MUPs predict pathologic changes of muscle fiber necrosis, splitting, and/or vacuolar changes (as seen with inflammatory myopathies and muscular dystrophies). Absence of fibrillation potentials suggests other myopathologic changes (e.g., congenital myopathy). Muscle Nerve 59 :315–320, 2019

ABSTRACTIntroduction: Routine ulnar nerve conduction studies may be normal in very mild ulnar neuropathies at the elbow (UNE). Short segment ulnar sensory stimulation across the elbow may detect mild abnormalities in these cases. Methods: Short segment ulnar sensory nerve stimulation was performed in 20 controls and 15 patients with clinically suspected mild UNE. Greatest peak latency shift and amplitude drop between 2 adjacent stimulation sites were calculated. Results: The upper limit of normal for peak latency shift and amplitude reduction between sites was 0.7 ms and 15%, respectively. Abnormal latency shift was detected in 12 of 15 patients and focal sensory conduction block in 6 of 15 patients. In 5 of 7 patients in whom all other studies were normal, sensory inching was abnormal. Discussion: Ulnar sensory short segment stimulation may provide diagnostic confirmation and localization of the site of nerve compression in mild UNE, and may improve UNE detection when all other studies are normal. Muscle Nerve 59:125–129, 2019

ABSTRACTIntroductionVoluntary doublets are electrophysiological phenomena thought to be associated with metabolic derangements or neuromuscular conditions.MethodsWe prospectively studied 232 consecutive patients examined by a single examiner during routine electromyography (EMG) to determine the frequency of doublets in individual patients, specific muscles, neuromuscular conditions, electrolyte levels, and doublet characteristics.ResultsOf 232 patients, 25 (10.7%) exhibited doublets. The mean age was 59 (52% men). Only 32 of 1,303 (2.5%) muscles exhibited doublets. Lower extremity and paraspinal groups represented 91% of muscles with doublets. Doublet frequency grouped by EMG diagnoses was: ALS (3 of 11; 27.1%), myopathy (3 of 10; 30.0%), axonal polyneuropathy (7 of 29; 24.1%), and no disease (7 of 109; 6.4%). There were no differences in serum electrolytes between doublet and matched subjects.ConclusionsDoublets occur in approximately 10% of patients, more commonly in lower extremity and paraspinal muscles, and are not correlated with a specific metabolic abnormality or neuromuscular condition. Muscle Nerve 55: 598–600, 2017

ABSTRACTIntroductionEosinophilic fasciitis (EF) is a rare disorder that can present with muscle symptoms that mimic other neuromuscular diseases.MethodsWe report the case of a 43‐year‐old woman with chronic muscle aches, tightness, and stiffness with hypertrophied, well‐defined muscles despite physical inactivity, and thickened skin with reduced elasticity and discoloration.ResultsExcept for mild peripheral eosinophilia, laboratory studies, including blood count, electrolytes, paraneoplastic panel, muscle enzymes, thyroid function, and serum protein electrophoresis, were normal. Nerve conduction studies and needle electromyography were normal. Magnetic resonance imaging of the thighs demonstrated superficial and deep fascial thickening with T2 hyperintensity and post‐gadolinium enhancement. Fascial and muscle biopsy demonstrated an inflammatory exudate in the perimysium and endomysium with fragmented perimysial connective tissue and thickened, inflamed fascia. EF was diagnosed. The patient was treated with methotrexate and prednisone followed by improvement of muscle stiffness and tightness.ConclusionEF should be considered when patients present with muscle pain or enlarged muscles. Muscle Nerve 56: 525–529, 2017