Meigen Liu

Effects of neurofeedback training with an electroencephalogram-based brain-computer interface for hand paralysis in patients with chronic stroke: a preliminary case series study.

OBJECTIVE To explore the effectiveness of neurorehabilitative training using an electroencephalogram-based brain- computer interface for hand paralysis following stroke. DESIGN A case series study. SUBJECTS Eight outpatients with chronic stroke demonstrating moderate to severe hemiparesis. METHODS Based on analysis of volitionally decreased amplitudes of sensory motor rhythm during motor imagery involving extending the affected fingers, real-time visual feedback was provided. After successful motor imagery, a mechanical orthosis partially extended the fingers. Brain-computer interface interventions were carried out once or twice a week for a period of 4-7 months, and clinical and neurophysiological examinations pre- and post-intervention were compared. RESULTS New voluntary electromyographic activity was measured in the affected finger extensors in 4 cases who had little or no muscle activity before the training, and the other participants exhibited improvement in finger function. Significantly greater suppression of the sensory motor rhythm over both hemispheres was observed during motor imagery. Transcranial magnetic stimulation showed increased cortical excitability in the damaged hemisphere. Success rates of brain-computer interface training tended to increase as the session progressed in 4 cases. CONCLUSION Brain-computer interface training appears to have yielded some improvement in motor function and brain plasticity. Further controlled research is needed to clarify the role of the brain-computer interface system.

Identification of a simple screening tool for dysphagia in patients with stroke using factor analysis of multiple dysphagia variables

OBJECTIVE To identify a most useful and simple clinical screening tool to predict videofluoroscopic aspiration in patients with stroke. DESIGN Factor analysis of multiple dysphagia variables and sensitivity and specificity testing with chi-square test. PATIENTS Sixty-one consecutive stroke patients with symptoms suggestive of dysphagia admitted to a university hospital and its 4 affiliated hospitals in Japan. METHODS Factors were extracted from 6 oromotor examinations (lip closure, tongue movement, palatal elevation, gag reflex, voice quality and motor speech function), 2 swallow screen tests (saliva swallowing test and our modified water swallowing test using 30 ml of water) and 4 parameters evaluated with a videofluoroscopic swallow study. Sensitivity and specificity of each dysphagia-related variable was determined against aspiration in a videofluoroscopic swallow study. RESULTS Factor analysis revealed that cough/voice change in the water swallowing test and aspiration on videofluoroscopic swallow study belonged to the same factor. Chi-square analysis showed that cough/voice change in the water swallowing test was the only variable that was significantly associated with aspiration on videofluoroscopic swallow study, with a sensitivity of 72% (95% CI: 61-83%) and a specificity of 67% (CI: 55-79%) as a predictor of aspiration (p<0.05). CONCLUSION We recommend our modified 30 ml water-swallowing test as a useful single task-screening tool to detect aspiration.

Event-related desynchronization reflects downregulation of intracortical inhibition in human primary motor cortex

There is increasing interest in electroencephalogram (EEG)-based brain-computer interface (BCI) as a tool for rehabilitation of upper limb motor functions in hemiplegic stroke patients. This type of BCI often exploits mu and beta oscillations in EEG recorded over the sensorimotor areas, and their event-related desynchronization (ERD) following motor imagery is believed to represent increased sensorimotor cortex excitability. However, it remains unclear whether the sensorimotor cortex excitability is actually correlated with ERD. Thus we assessed the association of ERD with primary motor cortex (M1) excitability during motor imagery of right wrist movement. M1 excitability was tested by motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) with transcranial magnetic stimulation (TMS). Twenty healthy participants were recruited. The participants performed 7 s of rest followed by 5 s of motor imagery and received online visual feedback of the ERD magnitude of the contralateral hand M1 while performing the motor imagery task. TMS was applied to the right hand M1 when ERD exceeded predetermined thresholds during motor imagery. MEP amplitudes, SICI, and ICF were recorded from the agonist muscle of the imagined hand movement. Results showed that the large ERD during wrist motor imagery was associated with significantly increased MEP amplitudes and reduced SICI but no significant changes in ICF. Thus ERD magnitude during wrist motor imagery represents M1 excitability. This study provides electrophysiological evidence that a motor imagery task involving ERD may induce changes in corticospinal excitability similar to changes accompanying actual movements.

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.

Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

BackgroundThe mu event-related desynchronization (ERD) is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS).MethodsSix healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs) were recorded near the left M1. ERD of the mu rhythm (mu ERD) by right hand motor imagery was measured. tDCS (10 min, 1 mA) was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT) of the left M1 were also measured with transcranial magnetic stimulation.ResultsMu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT.ConclusionsOpposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

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.

ADL structure for stroke patients in Japan based on the functional independence measure

Tsuji T, Sonoda S, Domen K, Saitoh E, Liu M, Chino N: ADL structure for stroke patients in Japan based on the Functional Independence Measure. Am J Phys Med Rehabil 1995;74:432—438 The difficulty patterns of FIM (Functional Independence Measure) in Japan were determined and compared with patterns found in the United States to assess whether FIM can be used for worldwide comparisons of ADL (the activities of daily living). The FIM was measured for 190 stroke patients in several hospitals throughout Japan. The scores at admission and discharge were converted to an interval scale by Rasch analysis. Right and left brain lesion patients were analyzed separately. The FIM items were divided into two groups: motor items and cognitive items to minimize misfit. A degree of misfit was acceptable, except for bowel and bladder management, stairs, bathing, and expression. Motor items, eating, and bowel and bladder management were the easiest; stairs, bathing, and tub/shower transfers were the most difficult. The difficulty patterns of patients with left and right hemisphere lesions were almost identical. Bathing and tub/shower transfer were more difficult for Japanese patients than for those studied in the United States. Concerning the cognitive items, expression was easiest for patients with right hemisphere lesions but most difficult for those with left hemisphere lesions. Social interaction was easier for Japanese patients with left hemisphere lesions than the other patients. The item difficulty patterns in Japan differs slightly from those in the United States because of cultural differences. As countries show different patterns of difficulty, we must be careful when making international comparisons of FIM data converted by Rasch analysis.

Muscle Damage Progression in Duchenne Muscular Dystrophy Evaluated by a New Quantitative Computed Tomography Method

The progression of muscle damage was studied in the lower extremity and trunk muscles of patients with Duchenne muscular dystrophy (DMD) with a new quantitative computed tomography (CT) method. The degree of muscle fiber loss and fat tissue replacement was quantified using the indices of percent cross-sectional area (%CSA) of muscle and fat, or the percentages of the area having the CT numbers of normal muscle and fat. A cross-sectional study in 71 patients showed that as the disability stage progressed, both CT number and %CSA of muscle decreased while %CSA of fat increased. The rate of progression was different for each muscle, and the order of involvement was clarified. The CT findings were also significantly correlated with muscle strength, indicating validity of our method. Our findings of the natural course of muscle involvement would be useful in providing appropriate rehabilitative care as well as assessing the efficacy of therapeutic interventions.

Brain-computer interface with somatosensory feedback improves functional recovery from severe hemiplegia due to chronic stroke.

Recent studies have shown that scalp electroencephalogram (EEG) based brain-computer interface (BCI) has a great potential for motor rehabilitation in stroke patients with severe hemiplegia. However, key elements in BCI architecture for functional recovery has yet to be clear. We in this study focused on the type of feedback to the patients, which is given contingently to their motor-related EEG in a BCI context. The efficacy of visual and somatosensory feedbacks was compared by a two-group study with the chronic stroke patients who are suffering with severe motor hemiplegia. Twelve patients were asked an attempt of finger opening in the affected side repeatedly, and the event-related desynchronization (ERD) in EEG of alpha and beta rhythms was monitored over bilateral parietal regions. Six patients were received a simple visual feedback in which the hand open/grasp picture on screen was animated at eye level, following significant ERD. Six patients were received a somatosensory feedback in which the motor-driven orthosis was triggered to extend the paralyzed fingers from 90 to 50°. All the participants received 1-h BCI treatment with 12–20 training days. After the training period, while no changes in clinical scores and electromyographic (EMG) activity were observed in visual feedback group after training, voluntary EMG activity was newly observed in the affected finger extensors in four cases and the clinical score of upper limb function in the affected side was also improved in three participants in somatosensory feedback group. Although the present study was conducted with a limited number of patients, these results imply that BCI training with somatosensory feedback could be more effective for rehabilitation than with visual feedback. This pilot trial positively encouraged further clinical BCI research using a controlled design.

Comorbidities in stroke patients as assessed with a newly developed comorbidity scale

We previously reported reliability and validity of our newly developed comorbidity scale (CS) for stroke outcome research based on a retrospective sample. The objectives of this study were to cross-validate the comorbidity scale in a new prospective sample and to investigate longitudinal changes of the comorbidity scale during hospitalization. In a prospective sample of 175 stroke patients admitted to five nonacute rehabilitation hospitals in Japan, we analyzed the frequency and grading of comorbidities and compared the comorbidity scale with demographic data, impairment as assessed with the Stroke Impairment Assessment Set (SIAS), and disability as measured with the Functional Independence Measure (FIM(SM)). The results were compared with our previous retrospective study. We also studied longitudinal changes by measuring the comorbidity scale on admission, 2 wk later, and at discharge of 67 patients. As a result, the comorbidity scaling was significantly lower in the prospective sample, and it increased at the second measurement and then plateaued. Among the comorbidities, hypertension ranked first, followed by shoulder pain, and diabetes mellitus. Similar to our previous retrospective study, the comorbidity scale correlated positively with age and length of stay and correlated negatively with the SIAS motor item scores and the FIM scores. In conclusion, the present study suggested concurrent and predictive validity of the comorbidity scale in a prospective sample as well and clarified the comorbidity characteristics of stroke inpatients.