Corticospinal and intracortical excitability of the quadriceps in patients with knee osteoarthritis

Abstract

Deficits in voluntary activation of the quadriceps muscle are characteristic of knee osteoarthritis (OA), contributing to the quadriceps weakness that is also a hallmark of the disease. The mechanisms underlying this central activation deficit (CAD) are unknown, although cortical mechanisms may be involved. Here, we utilize transcranial magnetic stimulation (TMS) to assess corticospinal and intracortical excitability in patients with knee osteoarthritis (OA) and in a comparably aged group of healthy older adults, to quantify group differences and to examine associations between TMS measures and pain, quadriceps strength, and CAD. Seventeen patients with knee OA and 20 healthy controls completed testing. Motor evoked potentials (MEPs) were measured at the quadriceps by superficial electromyographic (EMG) recordings. Corticospinal excitability was assessed by measuring resting motor threshold (RMT) to TMS stimulation of the quadriceps representation at primary motor cortex, and intracortical excitability was assessed via paired pulse paradigms for short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). No statistically significant differences between patients with knee OA and healthy controls were found for RMT, SICI or ICF measures (p>0.05). For patients with knee OA, there were significant associations observed between pain and RMT, as well as between pain and ICF. No associations were observed between CAD and measures of corticospinal or intracortical excitability. These data suggest against direct involvement of corticospinal or intracortical pathways within primary motor cortex in the mechanisms of CAD. However, pain is implicated in the neural mechanisms of quadriceps motor control in patients with knee OA.

The Association Between Corticomotor Excitability and Motor Skill Learning in People With Painful Hand Arthritis

“…36,39,40 Overall, chronic pain tends to be associated with a reduction in SICI, 8,9,11,12,14,15,41 although previous studies involving people with arthritis have failed to find evidence of motor cortex disinhibition. 12,42 We report reduced SICI with a conditioning intensity of 80% RTh but not 70%. It is known that SICF can contaminate measurements of SICI, particularly when using higher conditioning stimulus intensities.…”

Corticospinal and intracortical excitability differ between athletes early after ACLR and matched controls

“…The RMT was identified through single pulse TMS. The RMT was defined as the lowest stimulator intensity able to elicit a measurable response (MEP ≥ 50 μV, unamplified) in at least 5 out of 10 pulses delivered with the limb at rest . RMT is expressed as a percentage of the maximal stimulator output (%MSO) and reflects membrane excitability of the central core region of a muscles representation within the primary motor cortex .…”

Exercícios E Eletroestimulação Na Dor, Função E Plasticidade Cerebral De Indivíduos Com Osteoartrite De Joelho: O Estado Da Arte

“…(27) Entretanto apenas dois estudos examinaram o impacto da OA de joelho na plasticidade cortical avaliada com EMT. (28,29) Hunt et al, (28) em um estudo de um único caso, demonstraram que o PEM do músculo reto femoral estava diminuído na presença de OA de joelho, mas que voltaram ao normal após oito semanas de treinamento de força. (28) Kittelson et al, (29) conseguiram evidenciar correlações positivas entre dor e limiar de repouso e também entre dor e FIC.…”

“…(28,29) Hunt et al, (28) em um estudo de um único caso, demonstraram que o PEM do músculo reto femoral estava diminuído na presença de OA de joelho, mas que voltaram ao normal após oito semanas de treinamento de força. (28) Kittelson et al, (29) conseguiram evidenciar correlações positivas entre dor e limiar de repouso e também entre dor e FIC. (29) EXERCÍCIOS NA OA DE JOELHO O tratamento conservador baseado em exercícios terapêuticos pode melhorar função e a Qualidade de Vida (QV) de sujeitos com AO de joelho.…”

“…(28) Kittelson et al, (29) conseguiram evidenciar correlações positivas entre dor e limiar de repouso e também entre dor e FIC. (29) EXERCÍCIOS NA OA DE JOELHO O tratamento conservador baseado em exercícios terapêuticos pode melhorar função e a Qualidade de Vida (QV) de sujeitos com AO de joelho. (30) Exercícios físicos supervisionados de baixa intensidade são considerados padrão-ouro para dor e disfunção na AO.…”