Muscle velocity recovery cycles in myopathy

TY - JOUR

T1 - Muscle velocity recovery cycles in myopathy

AU - Meldgaard, M

AU - Kristensen, R S

AU - Z'Graggen, W J

AU - Tan, S V

AU - Søndergaard, K

AU - Qerama, E

AU - Andersen, H

AU - Fuglsang-Frederiksen, A

AU - Tankisi, H

PY - 2023/7

Y1 - 2023/7

N2 - OBJECTIVE: To understand the pathophysiology of myopathies by using muscle velocity recovery cycles (MVRC) and frequency ramp (RAMP) methodologies.METHODS: 42 patients with quantitative electromyography (qEMG) and biopsy or genetic verified myopathy and 42 healthy controls were examined with qEMG, MVRC and RAMP, all recorded from the anterior tibial muscle.RESULTS: There were significant differences in the motor unit potential (MUP) duration, the early and late supernormalities of the MVRC and the RAMP latencies in myopathy patients compared to controls (p < 0.05 apart from muscle relatively refractory period (MRRP)). When dividing into subgroups, the above-mentioned changes in MVRC and RAMP parameters were increased for the patients with non-inflammatory myopathy, while there were no significant changes in the group of patients with inflammatory myopathy.CONCLUSIONS: The MVRC and RAMP parameters can discriminate between healthy controls and myopathy patients, more significantly for non-inflammatory myopathy. MVRC differences with normal MRRP in myopathy differs from other conditions with membrane depolarisation.SIGNIFICANCE: MVCR and RAMP may have a potential in understanding disease pathophysiology in myopathies. The pathogenesis in non-inflammatory myopathy does not seem to be caused by a depolarisation of the resting membrane potential but rather by the change in sodium channels of the muscle membrane.

AB - OBJECTIVE: To understand the pathophysiology of myopathies by using muscle velocity recovery cycles (MVRC) and frequency ramp (RAMP) methodologies.METHODS: 42 patients with quantitative electromyography (qEMG) and biopsy or genetic verified myopathy and 42 healthy controls were examined with qEMG, MVRC and RAMP, all recorded from the anterior tibial muscle.RESULTS: There were significant differences in the motor unit potential (MUP) duration, the early and late supernormalities of the MVRC and the RAMP latencies in myopathy patients compared to controls (p < 0.05 apart from muscle relatively refractory period (MRRP)). When dividing into subgroups, the above-mentioned changes in MVRC and RAMP parameters were increased for the patients with non-inflammatory myopathy, while there were no significant changes in the group of patients with inflammatory myopathy.CONCLUSIONS: The MVRC and RAMP parameters can discriminate between healthy controls and myopathy patients, more significantly for non-inflammatory myopathy. MVRC differences with normal MRRP in myopathy differs from other conditions with membrane depolarisation.SIGNIFICANCE: MVCR and RAMP may have a potential in understanding disease pathophysiology in myopathies. The pathogenesis in non-inflammatory myopathy does not seem to be caused by a depolarisation of the resting membrane potential but rather by the change in sodium channels of the muscle membrane.

KW - Electromyography

KW - Frequency ramp

KW - Inflammatory myopathy

KW - Muscle velocity recovery cycles

KW - Non-inflammatory myopathy

KW - Membrane Potentials

KW - Humans

KW - Muscular Diseases

KW - Muscle Contraction/physiology

KW - Muscle, Skeletal

UR - http://www.scopus.com/inward/record.url?scp=85156177182&partnerID=8YFLogxK

U2 - 10.1016/j.clinph.2023.04.001

DO - 10.1016/j.clinph.2023.04.001

M3 - Journal article

C2 - 37148747

SN - 1388-2457

VL - 151

SP - 41

EP - 49

JO - Clinical Neurophysiology

JF - Clinical Neurophysiology

ER -