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Immobility and F‐waves: Impact on lower motor neuron excitability
Author(s) -
Pereira Mariana,
Swash Michael,
Carvalho Mamede
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.26817
Subject(s) - antidromic , f wave , h reflex , latency (audio) , lower limb , stimulation , reflex , medicine , psychology , physical medicine and rehabilitation , anesthesia , surgery , nerve conduction velocity , electrical engineering , engineering
Immobility of the upper limbs has been associated with reduction of F‐wave frequency. However, there are no similar studies on lower limb (LL) F‐waves. We investigated the impact of LL rest on F‐wave and H‐reflex parameters. Methods The LLs of 14 healthy participants were studied after 90 minutes rest. F‐waves (frequency, latencies, chronodispersion, and mean amplitude) and H‐reflexes (latency and recruitment curve) were investigated bilaterally. In seven participants the protocol was repeated, but the temperature of one limb was reduced. Results Immobility only changed F‐wave latencies, which increased significantly (mean value of 2 ms, P < .01). Limb cooling did not influence results. Discussion Contrary to what occurred in cervical lower motor neurons (LMN), LL LMNs did not show a reduced F‐wave response to immobility, but their latency increased significantly. This could have been due to reduced Renshaw inhibition of small LMNs, thus facilitating their response to antidromic stimulation and causing delayed late responses.