- Email: [email protected]
Cortical reorganisation of sub-acute transtibial amputees undertaking prosthetic rehabilitation
422 d
Abstracts / Brain Stimulation 8 (2015) 412e427
National Yang Ming University, Taipei, Taiwan
Introduction: Patterned electrical stimulation (PES) induces shortterm plasticity in spinal reciprocal inhibition (RI) (Perez et al. 2003). Fujiwara et al. (2011) showed that the effect of PES on the RI was modulated with motor cortex excitability induced by transcranial direct current stimulation. The aim of this study is to investigate the effects of different intensities of anodal tDCS on spinal plasticity of RI induced by PES. Methods: Seven healthy volunteers (mean age 293.2 SD) participated in this study. We applied electrical stimulation to the right common peroneal nerve with a train of 10 pulses at 100 Hz every 2 s for 20 min. Stimulus intensity was set at the motor threshold of the tibialis anterior muscle. Anodal tDCS was applied to the primary motor cortex for 20 min. The stimulation intensities of anodal tDCS delivered were either at 1 or 2 mA. The following four conditions were randomly tested in all participants: (1) anodal tDCS (1mA) alone; (2) anodal tDCS (2 mA) alone; (3) PES + anodal tDCS (1 mA); (4) PES + anodal tDCS (2 mA). RI was assessed with a soleus H reflex conditioning-test paradigm. The conditioning-test stimulus interval was set at 0, 1 and 2 ms. The RI was measured at baseline, immediately, 10, and 20 min after the paradigms. Results: PES + anodal tDCS (1 mA) significantly increased the amounts of RI immediately after and at 10 min and 20 min after the intervention compared to the baseline values (all p < 0.05). Anodal tDCS (2 mA) and PES + anodal tDCS (2 mA) significantly decreased the amounts of RI immediately after the intervention (in each p < 0.05). Discussion: We found that different intensities of anodal tDCS have different effects on spinal plasticity assessed with RI induced by PES.
366 Effects of caffeine on the quadripulse transcranial magnetic stimulation (QPS) induced long-term potentiation (LTP) Ryosuke Tsutsumi a,b, Nobuyuki Tanaka b, Takahiro Shimizu b, Yasuo Terao b, Yoshikazu Ugawa c, Ritsuko Hanajima a,b a Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan b Department of Neurology, The University of Tokyo, Tokyo, Japan c Department of Neurology, Fukushima Medical University, Fukushima, Japan Introduction: The primary motor cortical (M1) long-term potentiation (LTP)-like effect induced by quadripulse transcranial magnetic stimulation (QPS) is known to be involved and normalized with L-Dopa treatment in Parkinson’s disease (PD). Caffeine inhibits adenosine A1 receptor as well as adenosine A2A receptor. Since the A2A receptor is suggested to relate with PD pathogenesis, we hypothesized that caffeine would change M1 plasticity. In this study, we tested whether or not the caffeine intake affects QPS induced M1 LTP-like effect. Methods: Double-blinded crossover study was performed in 12 healthy subjects (6 women and 6 men; mean age 44.8 years old, SD 1.4). They received a single-dose of caffeine (200mg) or placebo tablet 2 hours before the QPS. We applied QPS over the left M1. The QPS protocol consisted of bursts of 4 monophasic transcranial magnetic stimulation (TMS) pulses separated by inter-stimulus intervals of 5 ms. We recorded motor evoked potentials (MEPs) to single pulse TMS over the left M1 from the relaxed right first dorsal interosseous muscles before and after QPS, every 5 minutes up to 30 minutes. Ten MEPs were recorded at each time point and the MEP ratio for each subject was obtained by dividing the averaged postQPS MEP by pre-QPS MEP. The time courses of MEP ratio for caffeine and placebo was compared using the paired t-test. Results: Eight subjects were “responder” and 4 subjects were “non-responder”, when “non-responder” was defined as those whose average MEP ratio was equal or less than 1. The MEP ratio
was significantly smaller with caffeine than placebo (p ¼ 0.038) in the responder group. Discussion: In the responders, caffeine significantly decreased LTP-like effect by QPS. It is compatible with the findings of previously reported animal experiments that the caffeine, A2A receptor antagonist, reduced LTP at the sensorimotor cortex, hippocampus and striatum.
367 Cortical reorganisation of sub-acute transtibial amputees undertaking prosthetic rehabilitation B.G. Hordacre a, L.V. Bradnam b, C. Barr c, B. Patritti d, M. Crotty c a Robinson Research Institute, University of Adelaide, Australia b Department of Physiotherapy, Flinders University of South Australia, Australia c Department of Rehabilitation and Aged Care, Flinders University of South Australia, Australia d Department of Rehabilitation and Aged Care, Repatriation General Hospital, Australia Extensive reorganisation of the contralateral motor cortex (M1) is well characterised in chronic lower-limb amputees. However, it is unclear how M1 reorganisation evolves during prosthetic rehabilitation, whether it occurs bilaterally and how it is related to lower-limb function. Thirteen acute transtibial amputees (10 male, mean age 61.1 years) and thirteen age-gender matched control participants were recruited. Single- and paired-pulse transcranial magnetic stimulation assessed corticomotor and intracortical excitability of M1 bilaterally. For amputee participants assessments were conducted at key rehabilitation phases (admission, prosthetic casting, first walk and discharge). For three amputees where surgery was elective, an additional pre-amputation neurophysiological assessment was performed 10.0 (SD 7.0) days prior to surgery. Spatial-temporal gait variability was assessed as a marker of lowerlimb function at discharge from rehabilitation. There were no differences for all neurophysiology measures between impending amputees and controls (all p>0.27) in this small subgroup (n¼3). No change in corticomotor excitability was observed across rehabilitation for all amputees. For M1 contralateral to the amputated side, short-latency intracortical inhibition was reduced at first walk compared to discharge (p¼0.003). Reduced inhibition at admission (p¼0.05) and first walk (p¼0.05) were associated with better gait function. For M1 ipsilateral to the amputated side, short-latency intracortical inhibition was reduced at admission (p¼0.01) and casting (p¼0.01) compared to discharge, while long-latency intracortical inhibition was reduced at admission (p¼0.05) and casting (p¼0.02) compared to first walk. Reduced short-latency intracortical inhibition at discharge was associated with poorer gait function (p¼0.05). There were no differences in corticomotor or intracortical excitability measures between amputees and controls at discharge. This study provides evidence of bilateral cortical reorganisation during prosthetic rehabilitation in transtibial amputees. There was a dichotomous relationship between reduced intracortical excitability for each M1 and gait function. This suggests intracortical inhibition may be a sensitive biomarker of gait function in transtibial amputees.
368 Cerebral blood flow augmentation by external counterpulsation enhances corticomotor excitability in subacute stroke patients: a randomized controlled trial J.Y. Liu a, C. Stinear b, H. Leung a, H.L. Ip a, S.Y. Fan a, Y.L. Lau a, W.H. Leung a, X.Y. Chen a, K.S. Wong a a The Chinese University of Hong Kong, Department of Medicine & Therapeutics, Faculty of Medicine, Hong Kong SAR
Abstracts / Brain Stimulation 8 (2015) 412e427
National Yang Ming University, Taipei, Taiwan
Introduction: Patterned electrical stimulation (PES) induces shortterm plasticity in spinal reciprocal inhibition (RI) (Perez et al. 2003). Fujiwara et al. (2011) showed that the effect of PES on the RI was modulated with motor cortex excitability induced by transcranial direct current stimulation. The aim of this study is to investigate the effects of different intensities of anodal tDCS on spinal plasticity of RI induced by PES. Methods: Seven healthy volunteers (mean age 293.2 SD) participated in this study. We applied electrical stimulation to the right common peroneal nerve with a train of 10 pulses at 100 Hz every 2 s for 20 min. Stimulus intensity was set at the motor threshold of the tibialis anterior muscle. Anodal tDCS was applied to the primary motor cortex for 20 min. The stimulation intensities of anodal tDCS delivered were either at 1 or 2 mA. The following four conditions were randomly tested in all participants: (1) anodal tDCS (1mA) alone; (2) anodal tDCS (2 mA) alone; (3) PES + anodal tDCS (1 mA); (4) PES + anodal tDCS (2 mA). RI was assessed with a soleus H reflex conditioning-test paradigm. The conditioning-test stimulus interval was set at 0, 1 and 2 ms. The RI was measured at baseline, immediately, 10, and 20 min after the paradigms. Results: PES + anodal tDCS (1 mA) significantly increased the amounts of RI immediately after and at 10 min and 20 min after the intervention compared to the baseline values (all p < 0.05). Anodal tDCS (2 mA) and PES + anodal tDCS (2 mA) significantly decreased the amounts of RI immediately after the intervention (in each p < 0.05). Discussion: We found that different intensities of anodal tDCS have different effects on spinal plasticity assessed with RI induced by PES.
366 Effects of caffeine on the quadripulse transcranial magnetic stimulation (QPS) induced long-term potentiation (LTP) Ryosuke Tsutsumi a,b, Nobuyuki Tanaka b, Takahiro Shimizu b, Yasuo Terao b, Yoshikazu Ugawa c, Ritsuko Hanajima a,b a Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan b Department of Neurology, The University of Tokyo, Tokyo, Japan c Department of Neurology, Fukushima Medical University, Fukushima, Japan Introduction: The primary motor cortical (M1) long-term potentiation (LTP)-like effect induced by quadripulse transcranial magnetic stimulation (QPS) is known to be involved and normalized with L-Dopa treatment in Parkinson’s disease (PD). Caffeine inhibits adenosine A1 receptor as well as adenosine A2A receptor. Since the A2A receptor is suggested to relate with PD pathogenesis, we hypothesized that caffeine would change M1 plasticity. In this study, we tested whether or not the caffeine intake affects QPS induced M1 LTP-like effect. Methods: Double-blinded crossover study was performed in 12 healthy subjects (6 women and 6 men; mean age 44.8 years old, SD 1.4). They received a single-dose of caffeine (200mg) or placebo tablet 2 hours before the QPS. We applied QPS over the left M1. The QPS protocol consisted of bursts of 4 monophasic transcranial magnetic stimulation (TMS) pulses separated by inter-stimulus intervals of 5 ms. We recorded motor evoked potentials (MEPs) to single pulse TMS over the left M1 from the relaxed right first dorsal interosseous muscles before and after QPS, every 5 minutes up to 30 minutes. Ten MEPs were recorded at each time point and the MEP ratio for each subject was obtained by dividing the averaged postQPS MEP by pre-QPS MEP. The time courses of MEP ratio for caffeine and placebo was compared using the paired t-test. Results: Eight subjects were “responder” and 4 subjects were “non-responder”, when “non-responder” was defined as those whose average MEP ratio was equal or less than 1. The MEP ratio
was significantly smaller with caffeine than placebo (p ¼ 0.038) in the responder group. Discussion: In the responders, caffeine significantly decreased LTP-like effect by QPS. It is compatible with the findings of previously reported animal experiments that the caffeine, A2A receptor antagonist, reduced LTP at the sensorimotor cortex, hippocampus and striatum.
367 Cortical reorganisation of sub-acute transtibial amputees undertaking prosthetic rehabilitation B.G. Hordacre a, L.V. Bradnam b, C. Barr c, B. Patritti d, M. Crotty c a Robinson Research Institute, University of Adelaide, Australia b Department of Physiotherapy, Flinders University of South Australia, Australia c Department of Rehabilitation and Aged Care, Flinders University of South Australia, Australia d Department of Rehabilitation and Aged Care, Repatriation General Hospital, Australia Extensive reorganisation of the contralateral motor cortex (M1) is well characterised in chronic lower-limb amputees. However, it is unclear how M1 reorganisation evolves during prosthetic rehabilitation, whether it occurs bilaterally and how it is related to lower-limb function. Thirteen acute transtibial amputees (10 male, mean age 61.1 years) and thirteen age-gender matched control participants were recruited. Single- and paired-pulse transcranial magnetic stimulation assessed corticomotor and intracortical excitability of M1 bilaterally. For amputee participants assessments were conducted at key rehabilitation phases (admission, prosthetic casting, first walk and discharge). For three amputees where surgery was elective, an additional pre-amputation neurophysiological assessment was performed 10.0 (SD 7.0) days prior to surgery. Spatial-temporal gait variability was assessed as a marker of lowerlimb function at discharge from rehabilitation. There were no differences for all neurophysiology measures between impending amputees and controls (all p>0.27) in this small subgroup (n¼3). No change in corticomotor excitability was observed across rehabilitation for all amputees. For M1 contralateral to the amputated side, short-latency intracortical inhibition was reduced at first walk compared to discharge (p¼0.003). Reduced inhibition at admission (p¼0.05) and first walk (p¼0.05) were associated with better gait function. For M1 ipsilateral to the amputated side, short-latency intracortical inhibition was reduced at admission (p¼0.01) and casting (p¼0.01) compared to discharge, while long-latency intracortical inhibition was reduced at admission (p¼0.05) and casting (p¼0.02) compared to first walk. Reduced short-latency intracortical inhibition at discharge was associated with poorer gait function (p¼0.05). There were no differences in corticomotor or intracortical excitability measures between amputees and controls at discharge. This study provides evidence of bilateral cortical reorganisation during prosthetic rehabilitation in transtibial amputees. There was a dichotomous relationship between reduced intracortical excitability for each M1 and gait function. This suggests intracortical inhibition may be a sensitive biomarker of gait function in transtibial amputees.
368 Cerebral blood flow augmentation by external counterpulsation enhances corticomotor excitability in subacute stroke patients: a randomized controlled trial J.Y. Liu a, C. Stinear b, H. Leung a, H.L. Ip a, S.Y. Fan a, Y.L. Lau a, W.H. Leung a, X.Y. Chen a, K.S. Wong a a The Chinese University of Hong Kong, Department of Medicine & Therapeutics, Faculty of Medicine, Hong Kong SAR