Katsuhiro Mizuno

Prism adaptation therapy enhances rehabilitation of stroke patients with unilateral spatial neglect: a randomized, controlled trial.

Background and objective. Unilateral spatial neglect (USN) can interfere with rehabilitation processes and lead to poor functional outcome. The purpose of this study was to determine whether prism adaptation (PA) therapy improves USN and functional outcomes in stroke patients in the subacute stage. Methods. A multicenter, double-masked, randomized, controlled trial was conducted to evaluate the effects of a 2-week PA therapy on USN assessed with the Behavioral Inattention Test (BIT), the Catherine Bergego Scale (CBS), and activities of daily living (ADL) as evaluated with the Functional Independence Measure (FIM). A total of 38 USN patients with right-brain damage were divided into prism (n = 20) and control (n = 18) groups. Patients were divided into mild and severe USN groups according to BIT behavioral test (mild ≥ 55 and severe<55). The prism group performed repetitive pointing with prism glasses that induce rightward optical shift twice daily, 5 days per week, for 2 weeks, whereas the control group performed similar pointing training with neutral glasses. Results. The FIM improved significantly more in the prism group. In mild USN patients, there was significantly greater improvement of BIT and FIM in the prism group. Conclusions. PA therapy can significantly improve ADL in patients with subacute stroke.

Development of a new measure to assess trunk impairment after stroke (trunk impairment scale): its psychometric properties.

Fujiwara T, Liu M, Tsuji T, Sonoda S, Mizuno K, Akaboshi K, Hase K, Masakado Y, Chino N: Development of a new measure to assess trunk impairment after stroke (Trunk Impairment Scale): Its psychometric properties. Am J Phys Med Rehabil 2004;83:681–688. Objective:The purpose of this study was to investigate reliability, validity, internal structure, and responsiveness of our newly developed Trunk Impairment Scale (TIS) for patients with stroke. Design:A total of 73 patients with stroke participated in this prospective study. Interrater reliability (weighted kappa statistics), content validity (principal component analysis), concurrent validity (Spearmans rank correlation with the Trunk Control Test), predictive validity (prediction of discharge FIM™ scores), and responsiveness (standardized response mean values) were examined. Internal consistency and item difficulties were analyzed with Rasch analysis. Results:The weighted kappa of each TIS item ranged from 0.66 to 1.0. Principal component analysis revealed that the TIS measured a domain similar to the Stroke Impairment Assessment Set trunk items but different from the Stroke Impairment Assessment Set motor and visuospatial items. The TIS correlated with the Trunk Control Test (r = 0.91). To predict discharge FIM motor scores, addition of the TIS as one of the predictors to age, time from onset, and admission FIM score increased the adjusted R2 from 0.66 to 0.75. With Rasch analysis, the misfit was acceptable, except for the abdominal muscle strength item. The difficulty patterns were similar at admission and discharge, except for the abdominal muscle strength item. The responsiveness of the TIS was satisfactory and comparable with that of the Trunk Control Test (standardized response mean values, 0.94 and 1.06). Conclusions:Our newly developed TIS is reliable, valid, and responsive for use in stroke outcome research.

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.

Early Visual Processing is Affected by Clinical Subtype in Patients with Unilateral Spatial Neglect: A Magnetoencephalography Study

Objective: To determine whether visual evoked magnetic fields (VEFs) elicited by right and left hemifield stimulation differ in patients with unilateral spatial neglect (USN) that results from cerebrovascular accident. Methods: Pattern-reversal stimulation of the right and left hemifield was performed in three patients with left USN. Magnetoencephalography (MEG) was recorded using a 160-channel system, and VEFs were quantified in the 400 ms after each stimulus. The presence or absence of VEF components at around 100 ms (P100m component) and 145 ms (N145m component) after stimulus onset was determined. The source of the VEF was determined using a single equivalent current dipole model for spherical volume conduction. All patients were evaluated using the behavioral inattention test (BIT). Results: In response to right hemifield stimulation, the P100m and N145m components of the VEF were evident in all three patients. In response to left hemifield stimulation, both components were evident in Patient 3, whereas only the P100m component was evident in Patient 1 and only the N145m component was evident in Patient 2. Patient 1 exhibited impairments on the line bisection and cancelation tasks of the BIT, Patient 2 exhibited impairments on the copying, drawing and cancelation tasks of the BIT, and Patient 3 exhibited impairments on the cancelation task of the BIT. Conclusion: These results demonstrate that early VEFs are disrupted in patients with USN and support the concept that deficits in visual processing differ according to the clinical subtype of USN and the lesion location. This study also demonstrates the feasibility of using MEG to explore subtypes of neglect.

The effects of patterned electrical stimulation combined with voluntary contraction on spinal reciprocal inhibition in healthy individuals

The aim of this study was to examine the effects of voluntary contraction (VC) on the modulation of reciprocal inhibition induced by patterned electrical stimulation (PES) in healthy individuals. Twelve healthy volunteers participated in this study. PES was applied to the common peroneal nerve with a train of 10 pulses at 100 Hz every 2 s for 20 min. VC comprised repetitive ankle dorsiflexion at a frequency of 0.5 Hz for 20 min. All participants performed the following three tasks: (i) VC alone, (ii) PES alone, and (iii) PES combined with VC (PES+VC). Reciprocal inhibition was assessed using a soleus H-reflex conditioning-test paradigm at the time points of before, immediately after, 10 min after, 20 min after, and 30 min after the tasks. PES+VC increased the amount of reciprocal inhibition, with after-effects lasting up to 20 min. PES alone increased reciprocal inhibition and maintained the after-effects on reciprocal inhibition for 10 min, whereas VC alone increased only immediately after the task. VC could modulate the plastic changes in spinal reciprocal inhibition induced by PES in healthy individuals. PES combined with VC has a potential to modulate impaired reciprocal inhibition and it may facilitate functional recovery and improve locomotion after central nervous system lesions.

Spatial and temporal dynamics of visual search tasks distinguish subtypes of unilateral spatial neglect: Comparison of two cases with viewer-centered and stimulus-centered neglect

We developed a computerised test to evaluate unilateral spatial neglect (USN) using a touchscreen display, and estimated the spatial and temporal patterns of visual search in USN patients. The results between a viewer-centered USN patient and a stimulus-centered USN patient were compared. Two right-brain-damaged patients with USN, a patient without USN, and 16 healthy subjects performed a simple cancellation test, the circle test, a visuomotor search test, and a visual search test. According to the results of the circle test, one USN patient had stimulus-centered neglect and a one had viewer-centered neglect. The spatial and temporal patterns of these two USN patients were compared. The spatial and temporal patterns of cancellation were different in the stimulus-centered USN patient and the viewer-centered USN patient. The viewer-centered USN patient completed the simple cancellation task, but paused when transferring from the right side to the left side of the display. Unexpectedly, this patient did not exhibit rightward attention bias on the visuomotor and visual search tests, but the stimulus-centered USN patient did. The computer-based assessment system provided information on the dynamic visual search strategy of patients with USN. The spatial and temporal pattern of cancellation and visual search were different across the two patients with different subtypes of neglect.

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.

F75. Hybrid-Assistive-Neuromuscular-Dynamic-Stimulation (HANDS) therapy induces cortical sensory plasticity in patients with chronic stroke

Introduction The hybrid assistive neuromuscular dynamic-stimulation (HANDS) therapy is closed-loop electromyography-controlled neuromuscular electrical stimulation (NMES) with a wrist-hand splint for patients with moderate to severe hemiparesis even including chronic stroke. It is repeatedly reported HANDS therapy induce significant recovery in upper extremity motor function for relatively severe paresis with a minimal ability for volitional muscle activation, who do not meet the criteria for other intensive therapies such as constrained-induced movement therapy. Although almost the half of stroke survivors are suffering from somatosensory impairment, and it is indicated that the sensory recovery would have a certain beneficial impact on motor functional recovery, neither the detailed mechanisms of somatosensory recovery nor the interaction with motor recovery are not determined enough especially for chronic stroke. On these ground, we have investigated the effect of HANDS therapy on the feature of sensory recovery. Methods For 23 chronic stroke patients with hemiplegia, 3 weeks inpatient HANDS therapy intervention was taken place. Median and Tibial nerve Sensory Evoked Potential (SEP) and behavioral sensory assessments including Semmes-Weinstein monofilament test and thumb-localizing test were performed at pre and posttreatment, as well as the motor functional assessments. Results A significant increase in the number of SEP peaks in the Median nerve and a significant reduction in the latency gap between N20 and P45 were observed in the paretic side after the intervention, whereas no significant difference was observed in any of these behavioral assessments. Although motor functional recovery was observed as in the previous studies, there was no significant correlation detected between motor function and each sensory related indices including SEP peak number and behavioral assessments. Conclusion Our result firstly suggests that closed-loop electromyography-controlled NMES training induce a sort of plastic changes especially in the level of cortex even in the chronic stroke patients. SEP would be a good evaluation modality which has higher sensitivity to detect a smaller plastic change induced by rehabilitative intervention.

Feasibility of a Respiratory Movement Evaluation Tool to Quantify Thoracoabdominal Movement for Neuromuscular Diseases

BACKGROUND: An objective method to evaluate thoracoabdominal movement is needed in daily clinical practice to detect patients at risk of hypoventilation and to allow for timely interventions in neuromuscular diseases. The clinical feasibility, reliability, and validity of a newly developed method for quantifying respiratory movement using fiber grating sensors, called the Respiratory Movement Evaluation Tool (RMET), was evaluated. METHODS: The time needed to measure respiratory movement and the usability of the measurement were determined by 5 clinicians using the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) 2.0 questionnaire. Thoracoabdominal movement was measured using RMET 3 times in 10 healthy subjects to evaluate intraclass correlation coefficients (ICC). The subjects were encouraged to breathe 10 times while voluntarily changing the amount of air during ventilation simultaneously with the RMET and a spirometer, and their correlations were evaluated to test validity using Pearsons product-moment correlation coefficients. The same measurements were also performed in 10 subjects with Duchenne muscular dystrophy. RESULTS: Real-time recordings of thoracoabdominal movements were obtained over a mean time of 374 ± 23.9 s. With QUEST 2.0, the median score of each item exceeded 3 (more or less satisfied). In healthy subjects, ICC(1,1) ranged from 0.82 to 0.99, and ICC(2,1) ranged from 0.83 to 0.97. Significant correlations were observed between the respiratory amplitudes measured with RMET, and the amount of air during ventilation was measured with a spirometer (r = 0.995, P < .001). In subjects with Duchenne muscular dystrophy, ICC(1,1) ranged from 0.87 to 0.97, and ICC(2,1) ranged from 0.84 to 0.99. The respiratory amplitudes measured with RMET correlated significantly with the amount of air during ventilation with a spirometer (r = 0.957, P < .001). CONCLUSIONS: We developed a novel method of quantifying respiratory movement called RMET that was feasible to use in daily clinical practice.

1-1-55. Changes of resting-state functional connectivity during prism adaptation in healthy adults: A fMRI study

Prism adaptation (PA) is one of the effective therapies for unilateral spatial neglect (USN), but its mechanism is not well understood. Under the hypothesis that PA is related to functional connectivity (FC) of visual attention network, we investigated the effects of the PA on FC in healthy adults with resting state functional magnetic resonance imaging (rsfMRI). Participants were 5 healthy right-handed volunteers. They wore prism glasses that deviate visual field to the right, and performed reaching task for the target without seeing the trajectory of their own hand. The angle of the prism glasses was gradually increased and the task was repeated 90 times. We estimated brain connectivity with rsfMRI before, immediately after, and one hour after the PA task. With pooled data of all the participants, the FC between left and right middle frontal gyrus decreased significantly immediately after the PA, and returned to baseline in one hour. Leftward deviation as a behavioral after effect seen immediately after the PA seemed to disappear in one hour. These results suggest that the FC in this region is modified by short term visuomotor adaptation. This study suggests that the PA can influence resting-state-functional connectivity between left and right visual attention network.