- Email: [email protected]
The effects of different intensities of anodal tDCS on spinal plasticity induced by patterned electrical stimulation
Abstracts / Brain Stimulation 8 (2015) 412e427
conventional HD-tDCS had 0.31 V/m of maximum cortical EF, while implanting the channel induced 1.6 V/m and 2.58 V/m peaks for shafts with diameter of 2 mm and 4 mm, respectively and it had more focal effects. T-shaped channels had increased peaks compared to shaft only. Finally, it was found that transcranial channels may yield the improved performance in intensity and focality compared to the conventional HD-tDCS; moreover, T-shaped channel had better performance than shaft only and was better for stabilizing the shaft relative to the skull.
362 Practical considerations for rTMS during pregnancy Praveen P. Fernandes MD Creighton University School of Medicine, Omaha, Nebraska, USA The treatment of depression during pregnancy poses a challenge, particularly during the first trimester when medications are best avoided. Several research articles in recent years have described the safe and effective use of rTMS during pregnancy, which appears to be a promising treatment for depression during pregnancy. While the technique for administering magnetic stimulation may not differ between pregnant and non-pregnant subjects, certain practical steps when followed can ensure a comfortable experience for the pregnant patient and improved discernment of clinical changes during treatment. A case of a woman treated for a depressive episode during the first trimester of pregnancy is described. The patient underwent a course of rTMS starting at the 10th week of pregnancy. Several clinical points are noted during the initiation and course of treatment, with practical suggestions on managing them when the need arises. These cover the areas of 1) diagnostic clarification of mood changes during early pregnancy, in the setting of discontinued maintenance medications, 2) preparing the patient for the sessions, in the setting of physiological changes and discomfort associated with early pregnancy, 3) monitoring mood changes during the course of TMS, in the setting of physical and psychosocial changes with passing weeks, 4) management of common side effects which may appear disproportionate to those experienced by non-pregnant subjects undergoing TMS. The recommendations listed should serve as a useful practical guide for monitoring and managing clinical issues arising during rTMS treatment of pregnant subjects.
363 Folk moxibustion as an effective therapy for cerebral palsy: a new direction for clinical research Tian-Sheng Fu , Qiwen Mu , Guoqiang Xing Intangible Cultural Heritage & Fu’s Moxibustion Clinic, Chengdu, Sichuan Province, Nanchong Hospital, Sichuan Province, PRC Lotus Biotech.com, Rockville, Maryland, USA Cerebral palsy (CP) is the most common neurological disorder that cause motor and language disabilities in children. CP is caused by a nonprogressive brain injury and/or malformation during brain development. Population-based studies report prevalence of CP ranging from 1.5 to more than 4 per 1,000 live births or children of a defined age range worldwide. In the US, 1 in 323 children has been identified with CP. A cross-sectional CP study of 388,192 children aged <7 years showed a prevalence of 1.6 per 1000 children or 2.8 per 1000 birthweightadjusted children in Jiangsu province, China in 1997 or estimated 310000 CP cases nationwide. As the survival of low birthweight infants improves, the prevalence of CP is much higher now. So far there is no proven effective therapeutics for CP. Here we report the clinical evidence of the safety and effectiveness of a folk moxibustion therapy for children with severe symptoms of cerebral palsy. Moxibustion is a traditional Chinese medicine (TCM) therapy using moxa made from dried mugwort (Artemisia argyi). Suppliers usually dry the mugwort and grind it up to a fluff before processing it further into a cigar-shaped
421
stick; Moxibustion practitioners burn the fluff or stick indirectly, with acupuncture needles, or burn it onto the patient’s skin. In this case, the practitioner successfully treated many children with multiple severe symptoms of CP who were diagnosed as impossible to be improved using current therapies by the experts from the nation’s top hospitals. In the presentation, we will present the clinical evidence of the moxibustion and review the current TCM theory underling the moxibustion therapy that improved the motor and language function of the children with CP. Further, we propose that more scientific research such as fMRI should be conducted to provide the scientific evidence and illustrate the mechanism underlying moxibustion therapy. 364 The efficacy of transcranial direct current stimulation in improving cognitive functioning in depression: A meta-analysis R.S.C. Lee a,*, D. Martin b, M. Kaur a, I.B. Hickie a, J. Lagopoulos a a Clincal Research Unit, Brain & Mind Research Institute, University of Sydney, Sydney, Australia b Black Dog Institute, University of New South Wales, Sydney, Australia *E-mail: [email protected]. Background: Evidence is emerging demonstrating the efficacy of transcranial direct current stimulation (tDCS) in the treatment of depression. However, whether tDCS is also efficacious in promoting lasting cognitive improvement remains unclear, despite evidence of cognitive enhancement after just one session. Here we sought to conduct a meta-analysis on randomized, double-blind, shamcontrolled trials of tDCS in depressive disorders. Methods: Electronic databases were searched for studies published between January 2006 and November 2014. Seven independent active tDCS samples from 6 studies met eligibility criteria (total N ¼ 142, mean age ¼ 46.8 years), and were each compared with respective sham tDCS samples (total N ¼ 140, mean age ¼ 46.4 years). All studies delivered anodal stimulation to the left dorsolateral prefrontal cortex (F3) for between 5 and 15 sessions, and currents ranged from 1 to 2 mA. Three studies placed the cathode over the lateral aspects of the contralateral orbits, whereas the others used the supraorbital region. Results: Compared with sham tDCS, active tDCS participants improved across psychomotor speed, attention span, working memory, and response inhibition, whereas verbal fluency and attentional set-shifting improved more after sham tDCS. Each pooled ES, however, was in the very small range (0.0-0.19), and all non-significant (p > 0.05). There was no evidence of significant heterogeneity across studies, or publication bias (all p > 0.05). Conclusions: There is limited evidence to suggest that tDCS as currently employed (electrical current strength, frequency/duration of delivery) is effective in promoting cognitive recovery in depressive disorders. Most studies have used small samples, not co-varied for mood improvement, and focused on recurrent-episode and middle-aged cohorts. Future studies may benefit from adjunctive treatments specifically developed to improve neuropsychological functioning, such as cognitive training, and should consider targeting recent-onset individuals in which cognitive deficits may be less entrenched and potentially more responsive to treatment. 365 The effects of different intensities of anodal tDCS on spinal plasticity induced by patterned electrical stimulation Tomofumi Yamaguchi a, Toshiyuki Fujiwara b, Yun-An Tsai c,d, Meigen Liu a a Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan b Department of Rehabilitation Medicine, Tokai University School of Medicine, Kanagawa, Japan c Center for Neural Regeneration, Taipei Veterans General Hospital, Taipei, Taiwan
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
conventional HD-tDCS had 0.31 V/m of maximum cortical EF, while implanting the channel induced 1.6 V/m and 2.58 V/m peaks for shafts with diameter of 2 mm and 4 mm, respectively and it had more focal effects. T-shaped channels had increased peaks compared to shaft only. Finally, it was found that transcranial channels may yield the improved performance in intensity and focality compared to the conventional HD-tDCS; moreover, T-shaped channel had better performance than shaft only and was better for stabilizing the shaft relative to the skull.
362 Practical considerations for rTMS during pregnancy Praveen P. Fernandes MD Creighton University School of Medicine, Omaha, Nebraska, USA The treatment of depression during pregnancy poses a challenge, particularly during the first trimester when medications are best avoided. Several research articles in recent years have described the safe and effective use of rTMS during pregnancy, which appears to be a promising treatment for depression during pregnancy. While the technique for administering magnetic stimulation may not differ between pregnant and non-pregnant subjects, certain practical steps when followed can ensure a comfortable experience for the pregnant patient and improved discernment of clinical changes during treatment. A case of a woman treated for a depressive episode during the first trimester of pregnancy is described. The patient underwent a course of rTMS starting at the 10th week of pregnancy. Several clinical points are noted during the initiation and course of treatment, with practical suggestions on managing them when the need arises. These cover the areas of 1) diagnostic clarification of mood changes during early pregnancy, in the setting of discontinued maintenance medications, 2) preparing the patient for the sessions, in the setting of physiological changes and discomfort associated with early pregnancy, 3) monitoring mood changes during the course of TMS, in the setting of physical and psychosocial changes with passing weeks, 4) management of common side effects which may appear disproportionate to those experienced by non-pregnant subjects undergoing TMS. The recommendations listed should serve as a useful practical guide for monitoring and managing clinical issues arising during rTMS treatment of pregnant subjects.
363 Folk moxibustion as an effective therapy for cerebral palsy: a new direction for clinical research Tian-Sheng Fu , Qiwen Mu , Guoqiang Xing Intangible Cultural Heritage & Fu’s Moxibustion Clinic, Chengdu, Sichuan Province, Nanchong Hospital, Sichuan Province, PRC Lotus Biotech.com, Rockville, Maryland, USA Cerebral palsy (CP) is the most common neurological disorder that cause motor and language disabilities in children. CP is caused by a nonprogressive brain injury and/or malformation during brain development. Population-based studies report prevalence of CP ranging from 1.5 to more than 4 per 1,000 live births or children of a defined age range worldwide. In the US, 1 in 323 children has been identified with CP. A cross-sectional CP study of 388,192 children aged <7 years showed a prevalence of 1.6 per 1000 children or 2.8 per 1000 birthweightadjusted children in Jiangsu province, China in 1997 or estimated 310000 CP cases nationwide. As the survival of low birthweight infants improves, the prevalence of CP is much higher now. So far there is no proven effective therapeutics for CP. Here we report the clinical evidence of the safety and effectiveness of a folk moxibustion therapy for children with severe symptoms of cerebral palsy. Moxibustion is a traditional Chinese medicine (TCM) therapy using moxa made from dried mugwort (Artemisia argyi). Suppliers usually dry the mugwort and grind it up to a fluff before processing it further into a cigar-shaped
421
stick; Moxibustion practitioners burn the fluff or stick indirectly, with acupuncture needles, or burn it onto the patient’s skin. In this case, the practitioner successfully treated many children with multiple severe symptoms of CP who were diagnosed as impossible to be improved using current therapies by the experts from the nation’s top hospitals. In the presentation, we will present the clinical evidence of the moxibustion and review the current TCM theory underling the moxibustion therapy that improved the motor and language function of the children with CP. Further, we propose that more scientific research such as fMRI should be conducted to provide the scientific evidence and illustrate the mechanism underlying moxibustion therapy. 364 The efficacy of transcranial direct current stimulation in improving cognitive functioning in depression: A meta-analysis R.S.C. Lee a,*, D. Martin b, M. Kaur a, I.B. Hickie a, J. Lagopoulos a a Clincal Research Unit, Brain & Mind Research Institute, University of Sydney, Sydney, Australia b Black Dog Institute, University of New South Wales, Sydney, Australia *E-mail: [email protected]. Background: Evidence is emerging demonstrating the efficacy of transcranial direct current stimulation (tDCS) in the treatment of depression. However, whether tDCS is also efficacious in promoting lasting cognitive improvement remains unclear, despite evidence of cognitive enhancement after just one session. Here we sought to conduct a meta-analysis on randomized, double-blind, shamcontrolled trials of tDCS in depressive disorders. Methods: Electronic databases were searched for studies published between January 2006 and November 2014. Seven independent active tDCS samples from 6 studies met eligibility criteria (total N ¼ 142, mean age ¼ 46.8 years), and were each compared with respective sham tDCS samples (total N ¼ 140, mean age ¼ 46.4 years). All studies delivered anodal stimulation to the left dorsolateral prefrontal cortex (F3) for between 5 and 15 sessions, and currents ranged from 1 to 2 mA. Three studies placed the cathode over the lateral aspects of the contralateral orbits, whereas the others used the supraorbital region. Results: Compared with sham tDCS, active tDCS participants improved across psychomotor speed, attention span, working memory, and response inhibition, whereas verbal fluency and attentional set-shifting improved more after sham tDCS. Each pooled ES, however, was in the very small range (0.0-0.19), and all non-significant (p > 0.05). There was no evidence of significant heterogeneity across studies, or publication bias (all p > 0.05). Conclusions: There is limited evidence to suggest that tDCS as currently employed (electrical current strength, frequency/duration of delivery) is effective in promoting cognitive recovery in depressive disorders. Most studies have used small samples, not co-varied for mood improvement, and focused on recurrent-episode and middle-aged cohorts. Future studies may benefit from adjunctive treatments specifically developed to improve neuropsychological functioning, such as cognitive training, and should consider targeting recent-onset individuals in which cognitive deficits may be less entrenched and potentially more responsive to treatment. 365 The effects of different intensities of anodal tDCS on spinal plasticity induced by patterned electrical stimulation Tomofumi Yamaguchi a, Toshiyuki Fujiwara b, Yun-An Tsai c,d, Meigen Liu a a Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan b Department of Rehabilitation Medicine, Tokai University School of Medicine, Kanagawa, Japan c Center for Neural Regeneration, Taipei Veterans General Hospital, Taipei, Taiwan
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