Tai Ryoon Han

Quantification of the path of center of pressure (COP) using an F-scan in-shoe transducer

By tracking the path of the center of pressure (COP) during the stance phase, the balance and pattern of progression can be determined. The path of COP is frequently used in clinical practice, although it is not quantified. In this study, an F-scan pressure sensitive insole system was used to quantify the path of COP. The COP of initial contact and the average during the stance phase corresponded to the center of the heel and to the center of the total plantar surface, respectively. The COP displacement corresponded to 83% of foot contact length and 18% of forefoot contact width. When the longitudinal axis of the insole was plotted as the Y-axis and the transverse axis of the insole as X-axis, the slopes of the COP coordinates during stance phase was 6 degrees inward. Velocities of the COP during each functional rocker action were even and 22-27 cm/s. The changes of quantified COP parameters according to the biomechanical alteration of the foot were confirmed by high-heeled gait.

Functional and Histologic Changes After Repeated Transcranial Direct Current Stimulation in Rat Stroke Model

Transcranial direct current stimulation (tDCS) is associated with enhancement or weakening of the NMDA receptor activity and change of the cortical blood flow. Therefore, repeated tDCS of the brain with cerebrovascular injury will induce the functional and histologic changes. Sixty-one Sprague-Dawley rats with cerebrovascular injury were used. Twenty rats died during the experimental course. The 41 rats that survived were allocated to the exercise group, the anodal stimulation group, the cathodal stimulation group, or the control group according to the initial motor function. Two-week treatment schedules started from 2 days postoperatively. Garcia, modified foot fault, and rota-rod performance scores were checked at 2, 9, and 16 days postoperatively. After the experiments, rats were sacrificed for the evaluation of histologic changes (changes of the white matter axon and infarct volume). The anodal stimulation and exercise groups showed improvement of Garcias and modified foot fault scores at 16 days postoperatively. No significant change of the infarct volume happened after exercise and tDCS. Neuronal axons at the internal capsule of infarct hemispheres showed better preserved axons in the anodal stimulation group. From these results, repeated tDCS might have a neuroprotective effect on neuronal axons in rat stroke model.

Multiple peripheral nerve compressions related to malignantly transformed hereditary multiple exostoses

Autosomal dominantly transmitted hereditary multiple exostoses is an uncommon disorder consisting of multiple projections of bone capped by cartilage. The lesions are most numerous in the metaphyses of long bones but may appear on flat bones. Sarcomatous transformation occurs in 1–25% of patients. We report a 33‐year‐old man with sciatica, previously diagnosed as hereditary multiple exostoses, presenting with multiple peripheral nerve compressions. Electrodiagnostic studies showed profound axon‐loss multiple neuropathies involving the sciatic, superior gluteal, and inferior gluteal nerves. Magnetic resonance imaging of the left pelvis showed a large mass in the sacral area that was suggestive of a chondrosarcoma. An open intralesional excision biopsy confirmed chondrosarcoma transformed from chondromatosis. Excision of the lesion was effective in eliminating the impingement of nerves and retarding progressive osseous growth. We suggest that malignant transformation be suspected in cases with focal compression neuropathy of patients known to have multiple exostoses. Osteochondroma as a possible cause for compression neuropathy is discussed.

Mechanism of functional recovery after repetitive transcranial magnetic stimulation (rTMS) in the subacute cerebral ischemic rat model: neural plasticity or anti-apoptosis?

Repetitive transcranial magnetic stimulation (rTMS) has been studied increasingly in recent years to determine whether it has a therapeutic benefit on recovery after stroke. However, the underlying mechanisms of rTMS in stroke recovery remain unclear. Here, we evaluated the effect of rTMS on functional recovery and its underlying mechanism by assessing proteins associated with neural plasticity and anti-apoptosis in the peri-lesional area using a subacute cerebral ischemic rat model. Twenty cerebral ischemic rats were randomly assigned to the rTMS or the sham group at post-op day 4. A total of 3,500 impulses with 10xa0Hz frequency were applied to ipsilesional cortex over a 2-week period. Functional outcome was measured before (post-op day 4) and after rTMS (post-op day 18). The rTMS group showed more functional improvement on the beam balance test and had stronger Bcl-2 and weaker Bax expression on immunohistochemistry compared with the sham group. The expression of NMDA and MAP-2 showed no significant difference between the two groups. These results suggest that rTMS in subacute cerebral ischemia has a therapeutic effect on functional recovery and is associated with an anti-apoptotic mechanism in the peri-ischemic area rather than with neural plasticity.

Effect of electroacupuncture on motor recovery in a rat stroke model during the early recovery stage.

The effect of acupuncture on motor recovery after stroke continues to be debated. This animal study was designed to determine whether acupuncture improves motor function following experimentally induced cerebral ischemia. In addition, we studied whether the outcome of motor function was associated with the expression of BDNF (brain derived neurotrophic factor), trkB (receptor, trkB) and infarct volume. Cerebral ischemia was induced by permanent middle cerebral artery occlusion (MCAO) or MCAO plus bilateral vertebral artery occlusion in Sprague-Dawley rats. The groups studied were a control, treadmill exercise, electroacupuncture and a combined treatment group with both treadmill exercise and electroacupuncture (ExEA). On postoperative day 16, Western blot analysis for BDNF and trkB and estimation of infarct volume were performed. The motor behavior scores were measured 2 and 16-days postoperatively. Comparison of the motor scores among the groups showed that the motor scores in the exercise only group and ExEA group were higher than in the control group on postoperative day 16. No statistical significance was found among the groups in the Western blot analysis and the infarct volume. This study demonstrates no significant additional effect of electroacupuncture on the motor recovery in rats following mild cerebral ischemia during the early recovery stage. Further studies in a rat model with moderate to severe cerebral ischemia, assessment and reassessment for more extended periods after the cerebral ischemia will be required.

Neuroprotective Effects of Growth Hormone Against Hypoxic-Ischemic Brain Injury in Neonatal Rats: 1H Magnetic Resonance Spectroscopic Study

Using 1H-MRS, we evaluated the effects of growth hormone (GH) as a caspase inhibitor on hypoxic-ischemic injury in neonatal rat brains. The right common carotid arteries of rats were ligated, allowed to recover for 3 hr, and exposed to 8% oxygen for 2 hr. GH was given just prior to HI insult and animals were divided into four groups: control, intracerebroventricular (ICV), intracerebroventricular/intraperitoneal (ICV/IP), and intraperitoneal (IP). Localized in vivo 1H-MRS and TUNEL staining were performed 24 hr after HI injury. Lipid/N-acetyl aspartate (NAA) and lipid/creatine (Cr) ratios were used as apoptotic markers. Gross morphologic changes at 2 weeks were used to evaluate the effects of GH. The lipid/NAA ratio was lower in the ICV and ICV/IP groups than in the control, and the lipid/Cr ratio was lower in the ICV group than in the control. The number of TUNEL positive cells was decreased in the ICV and ICV/IP groups, and the degree of morphologic change indicative of brain injury was lower in the ICV group and somewhat lower in the ICV/IP group. The degree of morphologic change correlated with the lipid/NAA and lipid/Cr ratios. These findings suggest that GH exerts neuroprotective effects in cerebral hypoxic-ischemic injury.

Electromyographic findings in nucleus pulposus-induced radiculopathy in the rat.

Study Design. This study was conducted to investigate the electromyographic changes and their pathophysiologic background in the animal model of nucleus pulposus-induced radiculopathy. Objectives. To observe the abnormal spontaneous activities in the electromyography (EMG) of rats with nucleus pulposus-induced radiculopathy and assess the role of nitric oxide in their development. Summary of Background Data. It has been shown that application of nucleus pulposus to nerve roots induces changes consistent with radiculopathy. However, to our knowledge, electromyographic findings and their background have never been studied in this model of radiculopathy. Methods. Autologous nucleus pulposus was harvested from the tails of Sprague-Dawley rats, and applied to L4 and L5 nerve roots. The rats were tested for mechanical allodynia, motor paresis, and needle EMG, before and after surgery. Specimens of nerve roots were stained histochemically for nitrotyrosine. Results. The rats had mechanical allodynia after surgery, but motor paresis was absent. EMG showed abnormal spontaneous activities after surgery, but only temporarily. Immunoreactivity for nitrotyrosine was detected in the cell bodies and axons of nerve roots. Conclusions. The data indicate that abnormal spontaneous activities can be observed in electromyographic examination of nucleus pulposus-induced radiculopathy. The development of these activities is considered related to nitric oxide-mediated protein nitration and resultant axonal dysfunction.

A new method to measure caudal motor conduction time using magnetic stimulation

Although central motor conduction time (CMCT) has been used for the diagnosis of lumbosacral spinal stenosis (LSSS), its diagnostic value is limited due to the short length of the involved segment compared to the long length of the total conduction distance. To overcome this, we introduce a new method to measure the caudal motor conduction time (caudal MCT) using magnetic stimulation. Magnetic stimulation was applied to the vertex and the T12 and S1 spinous processes for transcortical, thoracic, and sacral stimulation, respectively, and compound muscle action potentials were recorded simultaneously from the rectus abdominis (RA) and the right and left abductor hallucis (AH) muscles using three channels. CMCT was calculated by the latency difference in the AH response between transcortical and sacral stimulation, and between transcortical and thoracic stimulation for RA. Caudal MCT was calculated by subtracting CMCT for RA from that for AH. Caudal MCT was delayed in patients with LSSS compared to normal persons. We suggest that measuring caudal MCT may be useful for the diagnosis of LSSS, but its diagnostic sensitivity and specificity requires prospective study. Muscle Nerve, 2004

Korean Brain Rehabilitation Registry for Rehabilitation of Persons with Brain Disorders: Annual Report in 2009

This first annual report provides a description of patients discharged from rehabilitation facilities in Korea based on secondary data analysis of Korean Brain Rehabilitation Registry V1.0 subscribed in 2009. The analysis included 1,697 records of patients with brain disorders including stroke, traumatic brain injury, brain tumor and other disorders from 24 rehabilitation facilities across Korea. The data comprised 1,380 cases of stroke, 104 cases of brain injury, 55 cases of brain tumor, and 58 cases of other brain diseases. The functional status of each patient was measured using the Korean version of the Modified Barthel Index (KMBI). The average change in the KMBI score was 15.9 for all patients in the inpatient rehabilitation facility. The average length of stay for inpatient rehabilitation was 36.9 days. The transfer rates to other hospitals were high, being 62.4% when all patients were considered. Patients with brain disorders of Korea in 2009 and measurable functional improvement was observed in patients. However, relatively high percentages of patients were not discharged to the community after inpatient rehabilitation. Based on the results of this study, consecutive reports of the status of rehabilitation need to be conducted in order to provide useful information to many practitioners.

Inpatient stroke rehabilitation outcomes in Korea derived from the Korean Brain Rehabilitation Centers' online database system for the years 2007 to 2011.

The purpose of this report was to provide information for patients receiving inpatient rehabilitation after stroke and to identify the possible factors influencing functional outcome after inpatient rehabilitation. Stroke patients (n = 5,212) who were discharged from the Departments of Rehabilitation Medicine (RM) of university hospitals and rehabilitation hospitals from 2007 through 2011 were participants. Prevalence, age, transfer time after onset, length of stay (LOS), functional status at admission and discharge were analyzed. In all stroke subjects, cerebral infarctions (67%) were more common than hemorrhages. Cerebral infarctions in the middle cerebral artery territory were most common, while the basal ganglia and cerebral cortex were the most common areas for hemorrhagic stroke. The LOS decreased from 45 to 28 days. Transfer time after onset decreased from 44 to 30 days. Shorter transfer time after onset was correlated with better discharge functional status and shorter LOS. Initial functional status was correlated with discharge functional status. In ischemic stroke subtypes, cerebellar and brainstem strokes predicted better outcomes, while strokes with more than one territory predicted poorer outcomes with more disabilities. In hemorrhagic stroke subtypes, initial and discharge functional status was the lowest for cortical hemorrhages and highest for brainstem hemorrhages. This report shows that LOS and transfer time after onset has been decreased over time and initial functional status and shorter transfer after onset are predictors of better functional outcome at discharge.