Min-Kyun Oh

A Portable Gait Asymmetry Rehabilitation System for Individuals with Stroke Using a Vibrotactile Feedback

Gait asymmetry caused by hemiparesis results in reduced gait efficiency and reduced activity levels. In this paper, a portable rehabilitation device is proposed that can serve as a tool in diagnosing gait abnormalities in individuals with stroke and has the capability of providing vibration feedback to help compensate for the asymmetric gait. Force-sensitive resistor (FSR) based insoles are used to detect ground contact and estimate stance time. A controller (Arduino) provides different vibration feedback based on the gait phase measurement. It also allows wireless interaction with a personal computer (PC) workstation using the XBee transceiver module, featuring data logging capabilities for subsequent analysis. Walking trials conducted with healthy young subjects allowed us to observe that the system can influence abnormality in the gait. The results of trials showed that a vibration cue based on temporal information was more effective than intensity information. With clinical experiments conducted for individuals with stroke, significant improvement in gait symmetry was observed with minimal disturbance caused to the balance and gait speed as an effect of the biofeedback. Future studies of the long-term rehabilitation effects of the proposed system and further improvements to the system will result in an inexpensive, easy-to-use, and effective rehabilitation device.

The Effect of Extracorporeal Shock Wave Therapy on Lower Limb Spasticity in Subacute Stroke Patients

Objective To evaluate the effect of extracorporeal shock wave therapy (ESWT) on lower limb spasticity in subacute stroke patients. Methods We studied thirty hemiplegic subacute stroke patients with ankle plantar flexor spasticity. ESWT was applied for 1 session/week, with a total of 3 sessions at the musculotendinous junction of medial and lateral gastrocnemius muscles. Patients were evaluated both clinically and biomechanically at baseline, after sham stimulation, and at immediately 1 week and 4 weeks after ESWT. For clinical assessment, Modified Ashworth Scale (MAS), clonus score, passive range of motion of ankle, and Fugl-Myer Assessment for the lower extremity were used. A biomechanical assessment of spasticity was conducted by an isokinetic dynamometer. Two parameters, peak eccentric torque (PET) and torque threshold angle (TTA), were analyzed at the velocities of 60°/sec, 180°/sec, and 240°/sec. Results After sham stimulation, there were no significant changes between each assessment. MAS and PET (180°/sec and 240°/sec) were significantly improved immediately and 1 week after ESWT. However, these changes were not significant at 4 weeks after ESWT. PET (60°/sec) and TTA (60°/sec, 180°/sec, and 240°/sec) were significantly improved immediately after ESWT. Yet, these changes were not significant at 1 week and 4 weeks after ESWT as well. Conclusion Lower limb spasticity in subacute stroke patients was significantly improved immediately after ESWT. Although the therapeutic effect of ESWT reduced with time and therefore was not significant at 4 weeks after ESWT, the degree of spasticity was lower than that of the baseline. Future studies with a larger sample of patients are warranted in order to verify the protocols which can optimize the effect of ESWT on spasticity.

Medial Antebrachial Cutaneous Nerve Injury After Brachial Plexus Block: Two Case Reports

Medial antebrachial cutaneous (MABC) nerve injury associated with iatrogenic causes has been rarely reported. Local anesthesia may be implicated in the etiology of such injury, but has not been reported. Two patients with numbness and painful paresthesia over the medial aspect of the unilateral forearm were referred for electrodiagnostic study, which revealed MABC nerve lesion in each case. The highly selective nature of the MABC nerve injuries strongly suggested that they were the result of direct nerve injury by an injection needle during previous brachial plexus block procedures. Electrodiagnostic studies can be helpful in evaluating cases of sensory disturbance after local anesthesia. To our knowledge, these are the first documented cases of isolated MABC nerve injury following ultrasound-guided axillary brachial plexus block.

Reliability of the Pinch Strength with Digitalized Pinch Dynamometer

Objective To examine the intra-rater, inter-rater, and inter-instrumental reliability of the digitalized pinch muscle strength dynamometer. Method Thirty normal subjects were examined for pinch strength, using both the Preston pinch gauge and the digitalized pinch dynamometer. The participants performed all pinch strength tests in the seated position as recommended by the American Society of Hand Therapists (ASHT). Three successive measurements were taken for each hand. The mean of the three trials was used for data analysis. The pinch strength tests performed used a repeated measure design and measurements were taken by each rater. Results The relationship between the Preston pinch gauge and the digitalized pinch dynamometer in pinch strength was reliable (the ICC were 0.821 and 0.785 in rater 1 and rater 2 respectively). The relationship between the first session and second session in pinch strength using the digitalized pinch dynamometer was reliable (the ICC were 0.872 and 0.886 in rater A and rater B respectively). The relationship between rater A and rater B in pinch strength using the digitalized pinch dynamometer was reliable (the ICC was 0.754). Conclusion The pinch strength measurement using the digitalized pinch dynamometer is reliable within the rater and between raters. Thus, the Preston pinch gauge and the digitalized dynamometer measure grip strength equivalently, and can be used interchangeably.

The Availability of Radiological Measurement of Tibial Torsion: Three-Dimensional Computed Tomography Reconstruction

Objective To assess the intra-rater and inter-rater reliability for measuring tibial torsion measurements by a radiographic method using three-dimensional computed tomography reconstruction (3D-CT) and to compare the physical measures to those of 3D-CT. Method The study included 33 children who presented with intoeing gait. Tibial torsion was measured by 3D-CT. Distal reference point was the bimalleolar axis. Proximal reference points were the transtibial axis and posterior condylar axis. Physical measurements included thigh-foot angle (TFA) and bimalleolar angle (BMA). 3D-CT measurement and physical measurement were performed twice at both lower extremities by each rater. The intra-rater and inter-rater reliability were calculated by intraclass correlation coefficiency (ICC). The relationship between radiological and physical examination was calculated by Spearman correlation coefficient. Results The 3D-CT measures for tibial torsion were reliable within individual raters and between different raters. However, physical measures for tibial torsion were reliable within an individual rater but not reliable between raters. The 3D-CT measures by any proximal reference axis were more reliable within a rater and between raters than physical measurements. There was no significant impact introduced by the selection of the proximal reference axis. The correlation coefficiency between 3D-CT and physical measurement methods was low. Conclusion Because the 3D-CT measurements for tibial torsion are more reliable than physical measurements, we recommend that accurate diagnosis of internal tibial torsion should be detected by using 3D-CT measurements. Also, considering the disadvantages of radiological measurements, physical measurement may be used for short term follow-up by same raters, as intra-rater reliability is relatively good.

Haptic based gait rehabilitation system for stroke patients

Among most existing gait rehabilitation robots, it is difficult to find adequate devices for gait rehabilitation of chronic stroke patients who can already stand and move but still need to rehabilitate the affected lower limb through simple, compact, and easy-to use devices. This paper presents a novel haptic based gait rehabilitation system (HGRS) which has the potential to provide over-ground gait training regimens for post-stroke ambulatory subjects. It consists of a portable cane for kinesthetic sensing and a wearable vibrotactor array for tactile biofeedback. Contact of user with the handle provides light grip force, it serves the purpose of balance assurance and increased muscle activity through light touch concept and vibrotactors contribute in enhancing the gait modification through afferent signal of vibration. Walking trials conducted with stroke patients indicate increased muscle activation and balance, and improved temporal symmetry with use of HGRS. HGRS is capable of assisting physical therapists in training individuals with stroke suffering from gait abnormalities. In addition, it is easy to use and low-cost which makes it reachable to a vast domain of subjects suffering from gait abnormalities.

Development of an augmented feedback system for training of gait improvement using vibrotactile cues

Gait rehabilitation following stroke is often stated as the primary goal to improve quality of life. A wearable augmented feedback system which provides vibrotactile cues for post-stroke gait training is presented in this research. The system is capable of determining temporal gait parameters and thus identifies gait irregularities. A pair of custom-made insole, containing four Force Sensitive Resistors (FSRs) each, is being utilized to detect gait phase information. Each Insole is connected to a lily pad Arduino. Besides, the lily pad communicates with an XBee Wi-Fi, to provide connectivity with an operator PC in real-time. At the PC, the data from FSRs is being received in a custom-made LabVIEW® program. This program processes the data for real-time detection of temporal gait parameters and phase transitions. At the wearable system six vibrotactors are positioned at each shank to provide vibrotactile cues. These vibrotactors receive command of actuation from the LabVIEW program at PC, through lilypad over the XBee Wi-Fi. In the current research, a time-discrete vibrotactile cue is implemented for providing augmented feedback during walking. Five healthy subjects participated in an experimental trial to determine the capability of the system in delivery of time-discrete vibrotactile cues. Results indicate the systems usability and effectiveness in provision of augmented feedback for gait training.

Development of a multimodal biofeedback system for balance training

Biofeedback based exercises results in post-training improvements of postural stability. Various modalities have been used to provide a biofeedback system for training of balance control and postural stability. However a multimodal biofeedback system can offer more individualized training methods and hence provide therapists with a comprehensive solution for diverse patients. Individually, visual and haptic biofeedback has been identified as effective to reduce body sway in patients suffering from balance. So we have developed a novel multimodal system which provides biofeedback with both visual and haptic modality. Our system features a waist-attached smartphone, software running on a computer, a dedicated monitor for visual biofeedback and a dedicated Phantom Omni® device for haptic biofeedback. Experimental trials conducted with young healthy subjects demonstrate the effectiveness of the biofeedback system. The results indicate that a multimodal biofeedback system is found to be more effective in comparison with lone biofeedback of visual or haptic modality.

A novel robotic knee device with stance control and its kinematic weight optimization for rehabilitation

It is important to develop a robotic orthosis or exoskeleton that can provide back-drivable and good assistive performances with lightweight structures for overground gait rehabilitation of stroke patients. In this paper, we describe a robotic knee device with a five-bar linkage to allow low-impedance voluntary knee motion within a specified rotation range during the swing phase, and to assist knee extension during the stance phase. The device can provide free motion through the five-bar linkage with 2-degree-of-freedom (DOF) actuation via the patients shank using a linear actuator, and can assist knee extension at any controlled knee angle while bearing weight via a geared five-bar linkage with 1 DOF actuation of the linear actuator. The kinematic transition between the two modes can be implemented by contact with a circular structure and a linear link, and the resultant range of motion can be determined by the linear actuator. The kinematic weight of the device was optimized using the simple genetic algorithm to reduce the mass. The optimization cost function was based on the sum of the total link lengths and the actuator power. The optimization results reduced the total link length and motor power by 47% and 43%, respectively, compared to the initial design. We expect that the device will facilitate rehabilitation of stroke patients by allowing safe and free overground walking while providing support for stumbling.

The Effect of Human Placental Extract on Rheumatoid Arthritis in an Animal Model

Objective To assess the efficacy of human placental extract (HPE) in an animal model of rheumatoid arthritis (RA). Method We used (i) KRN C57BL/6 TCR transgenic x NOD mice (KBx/N) serum transfer arthritis and (ii) collagen-induced arthritis (CIA) mice to evaluate the effi cacy of HPE (1 ul or 100 ul, intra-peritoneal, three times per week) on RA. Incidence, severity of arthritis, and hind-paw thickness were quantifi ed. Joint destruction was analyzed using modifi ed mammographic imaging. Histopathological analysis for inflammation, cartilage, and osteoclasts was performed using Hematoxylin-eosin (H-E), safranin-O, and tartrate-resistant acidic phosphatase (TRAP). ELISAs were used for detection of various cytokines in serum and joint tissue. Results There were no significant differences in incidence of arthritis, clinical scores of arthritis, and hind-paw thickness between HPE-treated and vehicle-treated groups for up to 2 weeks in the KBx/N serum transfer arthritis model. Histopathological analysis also showed no differences 2 weeks after treatment. Levels of TNF-α, IL-1β, IL-6, IL-10, and RANKL in serum and joint tissues were similar in all groups. Furthermore, there were no differences in clinical, radiological, and histological parameters between HPE-treated and vehicle-treated group for 3 weeks in the CIA model. Conclusion Systemic treatment with HPE has no beneficial effects on arthritis in animal models of RA. Therefore, indiscreet use of HPE in RA should be forbidden.