Kaoru Honaga

Motor Improvement and Corticospinal Modulation Induced by Hybrid Assistive Neuromuscular Dynamic Stimulation (HANDS) Therapy in Patients With Chronic Stroke

Background and objective . We devised a therapeutic approach to facilitate the use of the hemiparetic upper extremity (UE) in daily life by combining integrated volitional control electrical stimulation with a wrist splint, called hybrid assistive neuromuscular dynamic stimulation (HANDS). Methods. Twenty patients with chronic hemiparetic stroke (median 17.5 months) had moderate to severe UE weakness. Before and immediately after completing 3 weeks of training in 40-minute sessions, 5 days per week over 3 weeks and wearing the system for 8 hours each day, clinical measures of motor impairment, spasticity, and UE functional scores, as well as neurophysiological measures including electromyography activity, reciprocal inhibition, and intracortical inhibition were assessed. A follow-up clinical assessment was performed 3 months later. Results. UE motor function, spasticity, and functional scores improved after the intervention. Neurophysiologically, the intervention induced restoration of presynaptic and long loop inhibitory connections as well as disynaptic reciprocal inhibition. Paired pulse transcranial magnetic stimulation study indicated disinhibition of the short intracortical inhibition in the affected hemisphere. The follow-up assessment showed that improved UE functions were maintained at 3 months. Conclusion. The combination of hand splint and volitional and electrically induced muscle contraction can induce corticospinal plasticity and may offer a promising option for the management of the paretic UE in patients with stroke. A larger sample size with randomized controls is needed to demonstrate effectiveness.

Transcranial direct current stimulation modulates the spinal plasticity induced with patterned electrical stimulation

OBJECTIVE Patterned sensory electrical stimulation (PES) has been shown to induce plasticity in spinal reciprocal Ia inhibition of the calf muscles. To study the cortical modulation of spinal plasticity, we examined the effects of giving transcranial direct current stimulation (tDCS) to the motor cortex before PES. METHODS Seven healthy volunteers participated in this study. PES involved stimulating the left common peroneal nerve at the fibular head with a train of 10 pulses at 100 Hz every 1.5s for 20 min using an intensity equal to the motor threshold of the tibialis anterior. tDCS was applied for 10 min before PES. For anodal stimulation, the electrode was placed over the motor cortex, and the cathodal electrode over the contralateral supraorbital area. For cathodal stimulation, the electrodes were reversed. Reciprocal inhibition was assessed using a soleus H reflex conditioning-test paradigm. RESULTS PES increased disynaptic reciprocal inhibition from the peroneal nerve to the soleus H reflex. When cathodal tDCS was applied before PES, PES no longer increased reciprocal inhibition. CONCLUSIONS Applying tDCS before PES modulated the effects of PES on spinal reciprocal inhibition in a polarity specific manner. SIGNIFICANCE We suggest that the motor cortex may play a role in spinal plasticity.

State of intracortical inhibitory interneuron activity in patients with chronic stroke

OBJECTIVES Few studies have assessed short intracortical inhibition (SICI) in the affected hemisphere (AH) in a large number of patients with chronic stroke. In this study, SICI was assessed in chronic stroke patients with severe hemiparesis, and its relationship to clinical parameters was examined. METHODS The participants were 72 patients with chronic hemiparetic stroke. SICI of both the AH and the unaffected hemisphere (UH) was assessed. The relationships between SICI and the location of lesion, time from onset, and finger function were studied. Motor function of the paretic finger was assessed with the Stroke Impairment Assessment Set (SIAS) and the Fugl-Meyer test upper extremity motor score. To compare the results with those of healthy subjects, SICI was assessed in seven age-matched control subjects. RESULTS MEPs of the UH were evoked in all 72 subjects, and MEPs of the AH were evoked in 24 subjects. SICI of the AH was inversely correlated with paretic finger motor function and time from stroke onset. SICI of the UH was not correlated with either one. SICI of the UH was higher in the cortical lesion group than in the control group. CONCLUSIONS The state of intracortical inhibitory neuron activity depends on the state of motor function and lesion site even in chronic stroke patients with severe hemiparesis. SIGNIFICANCE The inhibitory system of the AH is involved in functional recovery of the paretic hand even in the chronic stage of stroke.

Modulation of cortical and spinal inhibition with functional recovery of upper extremity motor function among patients with chronic stroke

PURPOSE We hypothesized that recovery of upper extremity motor function is associated with reduction of intracortical inhibition and improved reciprocal inhibition. This study examines the relationships of functional recovery in chronic stroke with the intracortical inhibition and spinal reciprocal inhibition. METHODS Participants were 61 patients with chronic hemiparetic stroke. The participants were applied hybrid assistive neuromuscular dynamic stimulation (HANDS) therapy for 3 weeks. The Fugl-Meyer test upper extremity motor score (FM) and modified Ashworth scale (MAS) were assessed before (T0), immediately after (T1) and 3 months after (T2) the end of HANDS therapy. A paired pulse TMS paradigm was applied to assess short intracortical inhibition (SICI). Reciprocal inhibition (RI) was assessed with H reflex conditioning-test paradigm. RESULTS FM and MAS were improved until T2. The change of FM from T0 to T2 was positively correlated with the change in affected SICI from T0 toT1. The change of wrist MAS from T0 to T1 was positively correlated with the change of RI. CONCLUSIONS In chronic stroke patients with moderate or severe hemiparesis, well-recovered patients showed disinhibition of ipsilesional hemisphere and increased resiprocal inhibition of forearm.

Associated reaction and spasticity among patients with stroke.

Honaga K, Masakado Y, Oki T, Hirabara Y, Fujiwara T, Ota T, Kimura A, Liu M: Associated reaction and spasticity among patients with stroke. Am J Phys Med Rehabil 2007;86:656–661. Objectives:The objectives were to investigate the relationship between associated reaction (AR) and clinical spasticity in the paretic arm. Design:The participants were ten patients with hemiparetic stroke, mean age of 65.2 yrs, and duration of stroke of 13.3 mos. The AR of the hemiparetic arm was analyzed with surface EMG, and AR ratio was calculated on the basis of comparison of the surface amplitude of the affected side to that of the nonaffected side. Simultaneously, we measured M-, H-, and T-wave amplitudes and calculated H/M and T/M in the paretic arm. The AR ratio, H/M, and T/M were compared with spasticity as assessed with the modified Ashworth scale (MAS). We repeated the same measurements after median nerve block to examine its effects on the parameters. Results:The AR ratio correlated significantly with MAS (P < 0.01), whereas H/M and T/M did not. Median nerve block did not alter these relationships. Conclusion:AR, which could be elicited easily in patients with spastic hemiparesis, correlated strongly with spasticity, both before and after the median nerve block. However, the so-called monosynaptic reflex (H- and T reflexes) did not correlate significantly with spasticity. These results indicate that AR and spasticity partially share common pathways.

Hybrid Assistive Neuromuscular Dynamic Stimulation Therapy: A New Strategy for Improving Upper Extremity Function in Patients with Hemiparesis following Stroke

Hybrid Assistive Neuromuscular Dynamic Stimulation (HANDS) therapy is one of the neurorehabilitation therapeutic approaches that facilitates the use of the paretic upper extremity (UE) in daily life by combining closed-loop electromyography- (EMG-) controlled neuromuscular electrical stimulation (NMES) with a wrist-hand splint. This closed-loop EMG-controlled NMES can change its stimulation intensity in direct proportion to the changes in voluntary generated EMG amplitudes recorded with surface electrodes placed on the target muscle. The stimulation was applied to the paretic finger extensors. Patients wore a wrist-hand splint and carried a portable stimulator in an arm holder for 8 hours during the daytime. The system was active for 8 hours, and patients were instructed to use their paretic hand as much as possible. HANDS therapy was conducted for 3 weeks. The patients were also instructed to practice bimanual activities in their daily lives. Paretic upper extremity motor function improved after 3 weeks of HANDS therapy. Functional improvement of upper extremity motor function and spasticity with HANDS therapy is based on the disinhibition of the affected hemisphere and modulation of reciprocal inhibition. HANDS therapy may offer a promising option for the management of the paretic UE in patients with stroke.

After-effects of pedaling exercise on spinal excitability and spinal reciprocal inhibition in patients with chronic stroke.

Purpose of the study: To evaluate the after-effects of pedaling on spinal excitability and spinal reciprocal inhibition in patients with post-stroke spastic hemiparesis. Materials and methods: Twenty stroke patients with severe hemiparesis participated in this study and were instructed to perform 7 min of active pedaling and 7 min of passive pedaling with a recumbent ergometer at a comfortable speed. H reflexes and M waves of paretic soleus muscles were recorded at rest before, immediately after and 30 min after active and passive pedaling. The Hmax/Mmax ratio and H recruitment curve were measured. Reciprocal inhibition was assessed using the soleus H reflex conditioning test paradigm. Results: The Hmax/Mmax ratio was significantly decreased after active and passive pedaling exercise. The decreased Hmax/Mmax ratio after active pedaling lasted at least for 30 min. The H recruitment curve and reciprocal inhibition did not change significantly after active or passive pedaling exercise. Conclusions: Pedaling exercise decreased spinal excitability in patients with severe hemiparesis. Pedaling may be effective in rehabilitation following stroke.

Voluntary contraction enhances spinal reciprocal inhibition induced by patterned electrical stimulation in patients with stroke

BACKGROUND Reciprocal inhibition (RI) may be important for recovering locomotion after stroke. Patterned electrical stimulation (PES) can modulate RI in a manner that could be enhanced by voluntary muscle contraction (VC). OBJECTIVE To investigate whether VC enhances the PES-induced spinal RI in patients with stroke. METHODS Twelve patients with chronic stroke underwent three 20 min tasks, each on different days: (1) PES (10 pulses, 100 Hz every 2 s) applied to the common peroneal nerve; (2) VC consisting of isometric contraction of the affected-side tibialis anterior muscle; (3) PES combined with VC (PES + VC). RI from the tibialis anterior to the soleus muscle was assessed before, immediately after, and 10, 20, and 30 min after the task. RESULTS Compared to the baseline, PES + VC significantly increased the changes in reciprocal inhibition at immediately after and 10 min after the task. PES alone significantly increased this change immediately after the task, while VC alone showed no significant increase. CONCLUSION VC enhanced the PES-induced plastic changes in RI in patients with stroke. This effect can potentially increase the success rate of newer neurorehabilitative approaches in achieving functional recovery after stroke.

Cancer Functional Assessment Set: a new tool for functional evaluation in cancer.

Objective The aim of this study was to develop and evaluate the psychometric properties of a new measurement tool, the Cancer Functional Assessment Set (cFAS). Design A total of 119 inpatients with cancer participated in this prospective cohort study. This study took place in three phases: (1) item generation, literature search, and a round-table discussion by 32 rehabilitation specialists; (2) item reduction and selection of appropriate items from the first item pool; and (3) evaluation of psychometric properties. Concurrent validity (Spearman correlation coefficients with existing scales), internal reliability (Cronbach coefficient alpha), interrater reliability (weighted kappa statistics and intraclass correlation coefficient), cross-validation, and responsiveness (standardized response mean values) were examined. Results The cFAS consisted of 24 items. Significant correlations were found between the cFAS and existing scales. Cronbach &agr; for the total score was 0.92. Weighted &kgr; values for each item ranged from 0.74 to 1.00. The intraclass correlation for the total score was 0.97. Concurrent validity and internal consistency were similar at two different hospitals. The cFAS was more responsive to changes than the other tools. Conclusions The cFAS has acceptable psychometric properties, supporting its broad generalizability. It can be a useful tool in clinical trials and can contribute to the development of cancer rehabilitation.

S4-4. Neurophysiological examination for the assessment of rehabilitation

Plasticity of motor cortex is considered to play an important role for recovery of motor function after stroke. Short intracortical inhibition (SICI) between affected and unaffected hemisphere and interhemispheric inhibition (IHI) are suggested to be involved in this plasticity. We examined SICI and IHI using transcranial magnetic stimulation technique in chronic stroke patients with severe hemiparesis to find out fundamentals for rehabilitation strategy. Results indicated individual variability of SICI in affected and unaffected hemisphere was very large, and SICI in unaffected hemisphere was not necessarily disinhibited. SICI in affected hemisphere was correlated with the period after the onset of stroke and motor function of the paretic hand. On the other hand, IHI varied depending on motor function of the paretic hand. These findings about SICI and IHI showed potential plasticity even in chronic stroke patients. We were investigating therapeutic effects of brain stimulation for the paretic hand. However, no consistent effects were demonstrated by the stimulation of either affected or unaffected hemisphere. Therefore based on the above findings, we would like to propose to checking SICI and IHI individually before treating paretic hand with brain stimulation.