Chung Sun Kim

Use of Virtual Reality to Enhance Balance and Ambulation in Chronic Stroke: A Double-Blind, Randomized Controlled Study

Kim JH, Jang SH, Kim CS, Jung JH, You JH: Use of virtual reality to enhance balance and ambulation in chronic stroke: A double-blind, randomized controlled study. Objective: To examine an additive effect of virtual reality on balance and gait function in patients with chronic hemiparetic stroke. Design: Twenty-four adults with hemiparetic stroke were randomly assigned to either an experimental group (n = 12) or a control group. Both groups underwent conventional physical therapy, 40 mins a day, 4 days a week for 4 wks. The experimental group received an additional 30 mins of virtual reality therapy each session. Balance performance was determined by the Balance Performance Monitor and Berg Balance Scale tests. Gait performance was determined by the 10-m walking test and Modified Motor Assessment Scale, and spatiotemporal parameters were obtained using GAITRite. Analysis of variance and correlation statistics were performed at P < 0.05. Results: In the balance test, the experimental group had improved Berg Balance Scale scores, balance and dynamic balance angles (ability to control weight shifting) compared with the controls (P < 0.05). In the gait performance test, the experimental group showed significant improvements in velocity, Modified Motor Assessment Scale scores, cadence, step time, step length, and stride length (P < 0.05). Improvement in dynamic balance angles was correlated with velocity and cadence (P < 0.01). Conclusions: This study demonstrates that virtual reality has an augmented effect on balance and associated locomotor recovery in adults with hemiparetic stroke when added to conventional therapy.

The effect of transcranial direct current stimulation on the cortical activation by motor task in the human brain: An fMRI study

OBJECTIVES We attempted to evaluate whether cortical activation resulting from hand movements is changed by transcranial direct current stimulation (tDCS) applied on the primary motor cortex for the hand in the human brain, using functional MRI (fMRI). METHODS Fourteen normal subjects were recruited; subjects were randomly assigned to either the tDCS group (n=7) or the sham group (n=7). fMRI was performed with hand grasp-release movements at 1Hz before and after 20 min of intervention (the tDCS group: anodal tDCS, the sham group: sham stimulation). RESULTS The activation of the tDCS underlying primary sensorimotor cortex (SM1) was significantly increased in the tDCS group (p<0.05). By contrast, the SM1 was significantly decreased in the sham group in terms of the voxel count and intensity (p<0.05). No subjects complained of any adverse symptoms or signs. CONCLUSION We demonstrated that anodal tDCS increased the cortical excitability of the underlying motor cortex in the human brain. It seems that tDCS is an effective modality to modulate brain function.

Functional Role of the Corticoreticular Pathway in Chronic Stroke Patients

Background and Purpose— The corticoreticular pathway (CRP) is known to be an important extrapyramidal tract for walking ability. However, little is known about the functional role of the CRP in recovery of walking ability. We investigated relation between the CRP and walking ability in chronic hemiparetic stroke patients. Methods— Among 209 consecutive patients, 54 patients, who showed complete injury of the corticospinal tract (CST) in the affected hemisphere on diffusion tensor tractography, and 20 normal subjects were recruited. Functional ambulation category was used in measurement of walking ability. The fractional anisotropy value, apparent diffusion coefficient value, and fiber volume of the CRP and CST were used for the diffusion tensor imaging parameters. Results— In the affected hemisphere, no significant difference in diffusion tensor imaging parameters of the CRP was observed between patient subgroups. In the unaffected hemisphere, patients who were able to walk showed significantly increased fiber volume of the CRP, compared with patients who could not walk and normal control subjects (P<0.05), without significant difference in fractional anisotropy and apparent diffusion coefficient values. In addition, the fiber volume of the CRP in the unaffected hemisphere showed positive correlation with functional ambulation category (P<0.05). In contrast, diffusion tensor imaging parameters of the CST in the unaffected hemisphere showed no correlation with functional ambulation category (P>0.05). Conclusions— The increased fiber volume of the CRP in the unaffected hemisphere seems to be related to walking ability in patients with chronic stroke. Therefore, the compensation of the CRP in the unaffected hemisphere seems to be one of the mechanisms for recovery of walking ability after stroke.

The effect of transcranial direct current stimulation on the motor suppression in stop-signal task.

PURPOSE This study examined whether transcranial direct current stimulation (tDCS) of the primary motor cortex alters the response time in motor suppression using the stop-signal task (SST). METHODS Forty healthy subjects were enrolled in this study. The subjects were assigned randomly to either the tDCS condition or sham control condition. All subjects performed a stop-signal task in three consecutive phases: without, during or after the delivery of anodal tDCS on the primary motor cortex (the pre-tDCS motor phase, on-tDCS motor phase, and after-tDCS motor phase). RESULTS The response times of the stopping process were significantly lower in each SST motor phase during or after tDCS (p < 0.05) and shorter immediately during delivery of the tDCS, whereas there was no change after the delivery of tDCS compared to sham condition. In contrast, the response times of the going process were similar under the two conditions (p > 0.05). No subjects complained of any adverse symptoms or signs. CONCLUSION Anodal tDCS enhances voluntary going and stopping of movement in executive control. tDCS appears to be an effective modality to modulate motor suppression and its related dynamic behavioral changes in motor sequential learning.

Differences of ground reaction forces and kinematics of lower extremity according to landing height between flat and normal feet

The study compared lower extremity kinematics and kinetics between male subjects with flat and normal feet when landing on both feet from platforms at different heights. Ten subjects with a flat feet arch and 10 subjects with a normal foot arch were recruited. They performed a double limb drop landing from 20, 40, and 60 cm onto a force-plate. A three-dimensional motion analysis system, force plates, and electromyography were used to analyze lower extremity kinetic and kinematic data. The GRF and angle of sagittal plane significantly increased with landing height in the flat foot group. In particular, hip joint angles at a height of 60 cm were significantly greater. The electromyography values were significantly higher for the tibialis anterior and vastus lateralis muscles, but were significantly lower in the abductor hallucis, gastrocnemius, and biceps femoris muscles in the flat foot group. GRF, joint angles, and muscle activity patterns in the lower extremities increases more with height in flat footed individuals than in people with a normal foot arch. Flat feet may aggravate the risk of shock on landing from a height; this might be ameliorated by a compensatory strategy at the hip joints to facilitate load distribution.

Changes of plantar pressure distributions following open and closed kinetic chain exercise in patients with stroke

OBJECTIVE The aim of this study is to investigate whether progressive resistive training with closed-kinetic chain (CKC) and open-kinetic chain (OKC) exercises could change plantar pressure distribution during walking in patients with stroke. METHODS Thirty-nine stroke patients were recruited and randomly divided into a CKC exercise group (n = 13), an OKC exercise group (n = 13), and a control group (n = 13). Both CKC and OKC exercise groups performed their own respective training programs 5 times per week for 6 weeks, whereas no training was done in the control group. Barefoot plantar pressure distribution was measured during walking in terms of contact area (CA), peak contact force (PCF), and contact impulse (CI) on each of three foot regions (i.e. forefoot (FF), midfoot (MF), and hindfoot (HF)). RESULTS In the CKC exercise group, there were significant changes in only the CA and PCF of HF. In the OKC exercise and control groups, no significant differences were found for all variables of plantar pressure distributions. CONCLUSION We found that resistive training with closed kinetic chain exercises could be an effective treatment method for improving normal gait patterns in stroke patients. These findings may be attributed to the fact that CKC exercise induced use of the ankle and knee muscles and provided repetitive sensory input from the affected foot.

Adverse effects of motor-related symptoms on the ipsilateral upper limb according to long-term cane usage.

OBJECTIVE Although the cane is prescribed to aid in daily living and social participation in stroke patients, this study aimed to identify whether long-term cane usage affected sensorimotor functions in the distal part of the non-affected upper limb in relation to a tracking task, a nine-hole pegboard test, and proprioceptive joint sense. PATIENT AND METHOD Forty stroke patients who were divided into a cane using group (CUG) or a non-cane using group (NCUG) participated in this study. Subjects were evaluated in a tracking task for visuomotor coordination, a nine-hole pegboard test for dexterous hand motion, and a joint reposition test for proprioceptive sense integrity. RESULT Comparison of the CUG and NCUG revealed significant differences in performance of the tracking task, the nine-hole pegboard test, and the joint reposition test (p < 0.05). The CUG had more difficulty performing visuomotor coordination and dexterous hand motion tasks compared with the NCUG. Proprioceptive joint sense was also deteriorated in the CUG. CONCLUSION These results suggest that stroke patients who use a cane for a long period, could experience decreased sensorimotor function in the ipsilateral upper limb of a damaged hemisphere. Therefore, it will be necessary to provide careful evaluation and appropriate therapeutic intervention for stroke patients who require the use of a cane over a long period.