Kosuke Oku

Revision of the Predictive Method Improves Precision in the Prediction of Stroke Outcomes for Patients Admitted to Rehabilitation Hospitals

[Purpose] The purpose of this study was to confirm the accuracy of a revised method for predicting the Functional Independence Measure (FIM) at discharge when stroke patients are first admitted to a rehabilitation hospital. [Subjects and Methods] The predictive equation with logarithmic trend line was calculated based on the total score of the FIM at admission and discharge in 93 patients with cerebral infarction (CI) and 60 patients with intracerebral hemorrhage (ICH). In other patients with CI or ICH (validation group), the differences between the actual FIM and the predicted FIM at discharge calculated by the CI or ICH equation and the combined (CI + ICH) equation, as well as by the CI or ICH equation and combined equation used in a previous study, were calculated. [Results] The multiple correlation coefficients of the CI equation, ICH equation, and combined equation were 0.87, 0.71, and 0.8. The residual of the actual FIM and predicted FIM at discharge calculated by the CI equation was the smallest in the CI validation group. In the ICH validation group, the residual calculated for ICH patients alone was smaller than that calculated by the previous ICH equation. [Conclusion] This easy-to-use method using a new equation for prediction was more precise than the previous equation. Therefore, we should revise the equation for predicting stroke patient outcome strata according to data from within the governing medical administration system.

Task dependency of the long-latency facilitatory effect on the soleus H-reflex by cerebellar transcranial magnetic stimulation.

We investigated whether cerebellar transcranial magnetic stimulation (C-TMS) facilitates the excitability of the ipsilateral soleus motoneuron pool in resting humans, and whether the facilitation is modulated by a task that promotes cerebellar activity. A test tibial nerve stimulus evoking the H-reflex from the right soleus muscle was delivered before or after conditioning C-TMS in prone individuals. The amplitude of the H-reflex was significantly increased at conditioning-test interstimulus intervals of 110, 120, and 130 ms. Furthermore, we revealed that this facilitation effect was inhibited while the individuals tapped their right index finger. These findings indicate that C-TMS facilitates spinal motoneuronal excitability with an ∼100 ms latency in resting humans, and that this cerebellar spinal facilitation is modulated by a task that might increase cerebellar activity. Cerebellar spinal facilitation could thus be useful for assessing the excitability of the cerebellum, or the cerebellar output to spinal motoneurons.

Effect of gaze-stabilization exercises on vestibular function during postural control

Gaze-stabilization exercise (GSE) is often conducted in vestibular rehabilitation, but its effect on vestibular function in postural control is not clear. We investigated whether GSE affects vestibular function during static upright standing and vestibulospinal reflex (VSR) in healthy young adults. First, the center of pressure of the total trajectory length (CoP-L) was measured before each GSE task or control (only standing) task (pre), immediately after (post), and 10 min after (post10) in the static standing position on foam rubber with the eyes open or closed (EC). Second, the H-reflex on the soleus muscle was measured after the onset of ipsilateral anodal galvanic vestibular stimulation before and after a GSE or a control task to estimate the amount of VSR induced by electrical vestibular input. CoP-L for the pre, post, and post10 control tasks and the GSE in EC did not differ significantly; the CoP-L for the post and post10 tasks in EC were significantly lower than that for the pretask. The H-reflex was inhibited by galvanic vestibular stimulation in the pre-GSE tasks. The inhibition increased after GSE, but not during control tasks. These findings suggest that GSE immediately improves the postural stability required for vestibular function and can be mediated by VSR improvements.

Effect of cerebellar transcranial magnetic stimulation on soleus Ia presynaptic and reciprocal inhibition.

Previously, we reported that cerebellar transcranial magnetic stimulation (C-TMS) facilitates spinal motoneuronal excitability in resting humans. In this study, we aimed to characterize the descending pathway that is responsible for the C-TMS-associated cerebellar spinal facilitation. We evaluated the effect of C-TMS on ipsilateral soleus Ia presynaptic inhibition (PSI) and reciprocal inhibition (RI) because the vestibulospinal and reticulospinal tracts project from the cerebellum to mediate spinal motoneurons via interneurons associated with PSI. PSI and RI were measured with a soleus H-reflex test following operant conditioning using electrical stimulation of the common peroneal nerve. C-TMS was delivered before test tibial nerve stimulation with conditioning-test interstimulus intervals of 110 ms. C-TMS did not generate motor-evoked potentials, and it did not increase electromyography activity in the ipsilateral soleus muscle, indicating that C-TMS does not directly activate the corticospinal tract and motoneurons. However, C-TMS facilitated the ipsilateral soleus H-reflex and reduced the amount of soleus Ia PSI, but not RI. These findings indicate that C-TMS may facilitate the excitability of the spinal motoneuron pool via the vestibulospinal or reticulospinal tracts associated with PSI. Cerebellar spinal facilitation may be useful for assessing the functional connectivity of the cerebellum and vestibular nuclei or reticular formation.

Prediction of Advisability of Returning Home Using the Home Care Score

Purpose. The aim of this study was to assess whether the home care score (HCS), which was developed by the Ministry of Health and Welfare in Japan in 1992, is useful for the prediction of advisability of home care. Methods. Subjects living at home and in assisted-living facilities were analyzed. Binominal logistic regression analyses, using age, sex, the functional independence measure score, and the HCS, along with receiver operating characteristic curve analyses, were conducted. Findings/Conclusions. Only HCS was selected for the regression equation. Receiver operating characteristic curve analysis revealed that the area under the curve (0.9), sensitivity (0.82), specificity (0.83), and positive predictive value (0.84) for HCS were higher than those for the functional independence measure, indicating that the HCS is a powerful predictor for advisability of home care. Clinical Relevance. Comprehensive measurements of the condition of provided care and the activities of daily living of the subjects, which are included in the HCS, are required for the prediction of advisability of home care.

Prediction of destination at discharge from a comprehensive rehabilitation hospital using the home care score

[Purpose] This study investigated whether it is possible to predict return to home at discharge from a rehabilitation hospital in Japan using the home care score of patients with cerebrovascular or osteoarticular disease and low activities of daily living at admission. [Subjects and Methods] The home care score and functional independent measurement were determined for 226 patients at admission and at discharge from five hospitals, and receiver operating characteristic analyses were conducted. [Results] The home care score cutoff point for the prediction of return to home at admission and at discharge was 11, and the area under the curve was more than 0.8. The area under the curve of the home care score was 0.77 for patients with low activities of daily living and within this group, the probability of return to home was approximately 50%, as predicted by the functional independent measurement. The home care score increased after receiving intervention at a rehabilitation hospital. [Conclusion] The home care score is useful for the prediction of return to home from a rehabilitation hospital, although prediction using the functional independent measurement is difficult for patients with low activities of daily living. Moreover, comprehensive interventions provided by the rehabilitation hospitals improve the ability to provide home care of the patient’s family, which is assessed by the home care score.

Gaze stabilization exercises derive sensory reweighting of vestibular for postural control

[Purpose] The aim of this study was to investigate whether gaze stabilization exercise derives sensory reweighting of vestibular for upright postural control. [Subjects and Methods] Twenty-three healthy volunteers participated in this study. The center of pressure of the total trajectory length was measured before (pre), immediately after (post), and 10 min after (post10) gaze stabilization exercise, in the static standing position, with the eyes open or closed, on the floor or on foam rubber. The sensory contribution values of the visual, somatosensory, and vestibular systems were calculated using center of pressure of the total trajectory length value in these measuring conditions. [Results] The center of pressure of the total trajectory length on foam rubber in post and post10 were significantly lower than that in the pre. The sensory contribution values of vestibular in post10 stages were significantly higher than that in pre-stage. [Conclusion] Gaze stabilization exercise can improve the static body balance in a condition that particularly requires vestibular function. The possible mechanism involves increasing sensory contribution of the vestibular system for postural control by the gaze stabilization exercise, which may be useful to derive sensory reweighting of the vestibular system for rehabilitation.

Vibration Applied to the Lateral Muscle of the Neck Induces Ipsilateral Body Sway during Sit-to-Stand Exercise in Healthy Adults â A Pilot Study

Background: The aim of this study was to investigate whether vibration that is applied to the lateral muscles of the neck induces the illusion that the body is swaying and compensatory body sway during sit-to-stand movements. Methods: Ten healthy adults participated in this examination. The center of pressure’s position during the sit-tostand exercise was measured immediately after the participant sat for 1 minute with their eyes closed, with or without vibration applied to the right side of the neck. The average center of pressure position in the anteriorposterior and left-right directions during the sit-to-stand exercise after the vibration was compared with and without vibration. After the task, we asked the participants about their sensation of body sway during the sit-to-stand movement, and the ratio of the appearance of the body sway and direction were compared between vibration conditions. Results: The sensation that the body swayed to the right due to vibration was significantly higher than that without vibration. The center of pressure’s position in the vibration condition was significantly deviated to the left compared with that without vibration. Conclusion: Our findings indicate that vibration applied to the right side of the neck induces the sense that the body is swaying to the right, although the body is actually swaying to the left. This actual body sway during the sit-tostand motion may compensate for an illusion that is induced by muscle vibrations, and this technique is possibly effective for posture control training.