Botulinum toxin modulates cortical maladaptation in post‐stroke spasticity

Huynh, William; Krishnan, Arun V.; Lin, Cindy S.‐Y.; Vucic, Steve; Katrak, Pesi; Hornberger, Michael; Kiernan, Matthew C.

doi:10.1002/mus.23719

Cited by 21 publications

(26 citation statements)

References 54 publications

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“…[29][30][31][32][33][34] The threshold-tracking strategy used a target response of 0.2 mV (±20%) located in the middle of the established linear relationship between the logarithm of the MEP amplitude and the stimulus intensity. 25 As such, selecting a target that is located in the steepest portion of the stimulus-response (SR) curve, relatively large variations in the MEP amplitude translate to relatively small variations in stimulus intensity or threshold.…”

Section: Cortical Excitabilitymentioning

confidence: 99%

Exploring the Evolution of Cortical Excitability Following Acute Stroke

Huynh

Vucic

Krishnan

et al. 2015

Neurorehabil Neural Repair

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The current study has demonstrated that evolution of intracortical excitability, particularly over the contralesional hemisphere, may vary between patients with differing baseline stroke and clinical characteristics, suggesting that ongoing contralesional network recruitment may be necessary for those patients who have significant disruptions to the integrity of ipsilesional motor pathways. Results from the present series have implications for the development of neuromodulatory brain stimulation protocols to harness and thereby facilitate stroke recovery.

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Section: Cortical Excitabilitymentioning

confidence: 99%

Exploring the Evolution of Cortical Excitability Following Acute Stroke

Huynh

Vucic

Krishnan

et al. 2015

Neurorehabil Neural Repair

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“…In addition, reduction of SICI over the contralateral and ipsilateral (unaffected) motor cortex was previously reported in acute stroke and was associated with a greater severity of functional limb impairment (Huynh et al. ,b,c). Of further relevance, normalization of SICI was reported secondary to botulinum toxin therapy and correlated with improvement in limb spasticity, suggesting the importance of modulating maladaptive cortical plasticity as a therapeutic approach (Huynh et al.…”

Section: Discussionmentioning

confidence: 65%

“…Of further relevance, normalization of SICI was reported secondary to botulinum toxin therapy and correlated with improvement in limb spasticity, suggesting the importance of modulating maladaptive cortical plasticity as a therapeutic approach (Huynh et al. ,b,c). Consequently, rehabilitative and pharmacological strategies aimed at restoring the cortical processes involved in regulating complex hand tasks, particularly functional coupling of the descending corticomotoneuronal volleys may prove therapeutically useful in humans.…”

Section: Discussionmentioning

confidence: 99%

Motor cortical function and the precision grip

et al. 2014

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While task‐dependent changes in motor cortical outputs have been previously reported, the issue of whether such changes are specific for complex hand tasks remains unresolved. The aim of the present study was to determine whether cortical inhibitory tone and cortical output were greater during precision grip and power grip. Motor cortex excitability was undertaken by using the transcranial magnetic stimulation threshold tracking technique in 15 healthy subjects. The motor‐evoked potential (MEP) responses were recorded over the abductor pollicis brevis (APB), with the hand in the following positions: (1) rest, (2) precision grip and (3) power grip. The MEP amplitude (MEP amplitude REST 23.6 ± 3.3%; MEP amplitude PRECISION GRIP 35.2 ± 5.6%; MEP amplitude POWER GRIP 19.6 ± 3.4%, F = 2.4, P < 0.001) and stimulus‐response gradient (SLOPEREST 0.06 ± 0.01; SLOPEPRCISION GRIP 0.15 ± 0.04; SLOPE POWER GRIP 0.07 ± 0.01, P < 0.05) were significantly increased during precision grip. Short interval intracortical inhibition (SICI) was significantly reduced during the precision grip (SICI REST 15.0 ± 2.3%; SICI PRECISION GRIP 9.7 ± 1.5%, SICI POWER GRIP 15.9 ± 2.7%, F = 2.6, P < 0.05). The present study suggests that changes in motor cortex excitability are specific for precision grip, with functional coupling of descending corticospinal pathways controlling thumb and finger movements potentially forming the basis of these cortical changes.

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“…BoNT-A on activities related to muscle stretch reflexes, such as an effect on -motor neurons at the neuromuscular junction, a change in stimulation of Ia muscle spindles due to degeneration of -neurons, decreased co-contraction, and decreased Renshaw inhibition of the H reflex 18 . In addition, a study of stroke patients has demonstrated that short-interval intracortical inhibition in the unaffected cerebral hemisphere recovers to a normal level after BoNT-A injection, suggesting an effect on the central nervous system 19 .…”

Section: Discussionmentioning

confidence: 99%

Comparison of Plantar Pressure and Plantar Contact Area before and after Botulinum Toxin Type A(BoNT-A)Therapy in Stroke Patients with Lower Limb Spasticity

Kawate

Matsumoto²,

Iijima

2017

Showa Univ J Med Sci

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: The effectiveness of botulinum toxin type A BoNT-A therapy for reducing muscle spasticity has been reported. We examined changes in the plantar contact area and plantar pressure after BoNT-A injection therapy in stroke patients with spastic hemiparesis. The study participants were 12 male hemiparetic stroke patients treated in our outpatient clinic right hemiparesis, 7 ; left, 5 , who were able to walk without orthoses. They were requested to walk barefoot at their normal walking speed on a sheet with pressure measurement sensors, before, and at one and three months after BoNT-A therapy. Simultaneously the maximum plantar pressures and maximum plantar contact areas of both feet during the standing phase of walking were analyzed using a pressure distribution measuring system. The ratios of the measured values for the affected side to that of the unaffected side were calculated. The mean ratio of the maximum plantar pressure of the affected / unaffected limb on standing changed from 61.5 12.4 to 75.0 9.5 at one month, and 61.2 7.3 at three months after BoNT-A therapy. The mean maximum plantar contact area ratios also changed from 75.3 11.7 to 87.9 8.7 at one month and 77.8 8.8 at three months. For both parameters, the ratios were signi cantly increased at one month after BoNT-A, compared to the other time points P 0.01 . These results suggest that BoNT-A therapy reduces muscle spasticity of the lower limbs, which improves the range of motion of the ankle joints, leading to improved plantar contact during the standing phase of walking. This pressure measurement system may be useful for assessing the effectiveness of BoNT-A therapy.

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Botulinum toxin modulates cortical maladaptation in post‐stroke spasticity

Abstract: Cortical excitability changes were demonstrated in UH, suggesting that the clinical benefits of botulinum toxin relate to modulation of abnormal central reorganization (maladaptive plasticity) in post-stroke spasticity.

Cited by 21 publications

References 54 publications

Exploring the Evolution of Cortical Excitability Following Acute Stroke

Exploring the Evolution of Cortical Excitability Following Acute Stroke

Motor cortical function and the precision grip

Comparison of Plantar Pressure and Plantar Contact Area before and after Botulinum Toxin Type A(BoNT-A)Therapy in Stroke Patients with Lower Limb Spasticity

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