Effect of Ankle-foot Orthosis on Lower Limb Muscle Activities and Static Balance of Stroke Patients Authors' Names

Virtual reality-based balance training system augmented with operant conditioning paradigm

Background

Stroke-related sensory and motor deficits often steal away the independent mobility and balance from stroke survivors. Often, this compels the stroke survivors to rely heavily on their non-paretic leg during weight shifting to execute activities of daily living (ADL), with reduced usage of the paretic leg. Increased reliance on non-paretic leg often leads to learned nonuse of the paretic leg. Therefore, it is necessary to measure the contribution of individual legs toward one’s overall balance. In turn, techniques can be developed to condition the usage of both the legs during one’s balance training, thereby encouraging the hemiplegic patients for increased use of their paretic leg. The aim of this study is to (1) develop a virtual reality (VR)-based balance training platform that can estimate the contribution of each leg during VR-based weight-shifting tasks in an individualized manner and (2) understand the implication of operant conditioning paradigm during balance training on the overall balance of hemiplegic stroke patients.

Result

Twenty-nine hemiplegic patients participated in a single session of VR-based balance training. The participants maneuvered virtual objects in the virtual environment using two Wii Balance Boards that measured displacement in the center of pressure (CoP) due to each leg when one performed weight-shifting tasks. For operant conditioning, the weight distribution across both the legs was conditioned (during normal trial) to reward participants for increased usage of the paretic leg during the weight-shifting task. The participants were offered multiple levels of normal trials with intermediate catch trial (with equal weight distribution between both legs) in an individualized manner. The effect of operant conditioning during the normal trials was measured in the following catch trials. The participants showed significantly improved performance in the final catch trial compared to their initial catch trial task. Also, the enhancement in CoP displacement of the paretic leg was significant in the final catch trial compared to the initial catch trial.

Conclusion

The developed system was able to encourage participants for improved usage of their paretic leg during weight-shifting tasks. Such an approach has the potential to address the issue of learned nonuse of the paretic leg in stroke patients.

Effect of twister wrap orthosis on foot pressure distribution and balance in diplegic cerebral palsy

OBJECTIVES

To evaluate the effectiveness of twister wrap orthosis (TWO) on foot pressure distribution and postural balance in children with spastic diplegic cerebral palsy (CP).

METHODS

Thirty children with spastic diplegic CP, with ages ranging from 6 to 8 years, were assigned randomly into two groups. The control group received the conventional physical therapy and ankle foot orthosis (AFO), whereas the study group received the same program as the control group in addition to TWO. Measurement of foot pressure distribution using a pressure platform as well as stability indices using the Biodex Stability System was performed before and after 12 weeks of the treatment program.

RESULTS

Both groups showed a significant increase in mean and peak planter pressure on forefoot and rear foot with a significant decrease on mid foot after treatment (P⟨0.05). The study group showed a significant improvement in balance after treatment (P⟨0.05) while there was no significant difference in the control group. After treatment, the study group showed significant improvement in planter pressure and balance compared with the control group (P⟨0.05).

CONCLUSIONS

TWO could provide correction of foot pressure distribution and improve postural balance in children with spastic diplegic CP.

Virtual Reality-Based Center of Mass-Assisted Personalized Balance Training System

Poststroke hemiplegic patients often show altered weight distribution with balance disorders, increasing their risk of fall. Conventional balance training, though powerful, suffers from scarcity of trained therapists, frequent visits to clinics to get therapy, one-on-one therapy sessions, and monotony of repetitive exercise tasks. Thus, technology-assisted balance rehabilitation can be an alternative solution. Here, we chose virtual reality as a technology-based platform to develop motivating balance tasks. This platform was augmented with off-the-shelf available sensors such as Nintendo Wii balance board and Kinect to estimate one’s center of mass (CoM). The virtual reality-based CoM-assisted balance tasks (Virtual CoMBaT) was designed to be adaptive to one’s individualized weight-shifting capability quantified through CoM displacement. Participants were asked to interact with Virtual CoMBaT that offered tasks of varying challenge levels while adhering to ankle strategy for weight shifting. To facilitate the patients to use ankle strategy during weight-shifting, we designed a heel lift detection module. A usability study was carried out with 12 hemiplegic patients. Results indicate the potential of our system to contribute to improving one’s overall performance in balance-related tasks belonging to different difficulty levels.

Impact of wearing a functional foot orthotic on the ankle joint angle of frontal surface of young adults with flatfoot

[Purpose] This study investigated the effects of proprietary foot orthotics in young adults with flatfoot to determine changes in the ankle joint angle in the coronal plane during the midstance phase. [Subjects and Methods] The subjects were 15 college students diagnosed with flatfoot. Changes in the ankle joint angle in the coronal plane in the midstance phase were measured using the Vicon Motion System before and after use of the orthotic. The data were analyzed using Statistical Package for the Social Sciences Win 16.0. [Results] The subjects showed significant increases in left and right ankle joint angles in the coronal plane during the midstance phase of the gait cycle after use of the orthotics. However, the difference between the left and right ankle joint angles showed no significant change, even though the difference increased after use of the orthotics. [Conclusion] Young adults with flatfoot showed increased ankle joint angles after use of the orthotics. This suggests that orthotic footwear can shape the plantar arch and affect the ankle joint, and that constant use of orthotics would cause a dynamic change in normal walking.

Effects of wearing functional foot orthotic on pelvic angle among college students in their 20s with flatfoot

[Purpose] This study examined the impact of wearing a functional foot orthotic on the pelvic angle of young adults who have flatfoot. [Subjects and Methods] A total of 15 college students diagnosed with flatfoot were included in the study. Changes in the pelvic angle in the stance period during walking before and after orthotic use were measured using a VICON Motion System (VICON, Hansung, Korea). The data were analyzed using SPSS 12.0 for Windows. [Results] In the experimental group, the pelvic angle during the mid-stance and mid-swing periods of the gait cycle significantly decreased on the left and right sides after wearing the orthotic, compared to the measurements taken before orthotic usage. The pelvic angle change on the left and right sides also decreased after wearing the orthotic, though this difference was not significant. [Conclusion] The pelvic angle of college students with flatfoot decreased after they wore orthotics. This implies that wearing orthotic shoes can greatly benefit individuals during normal walking by promoting passive changes that decrease the pelvic angle.

The influence of an ankle-foot orthosis on the spatiotemporal gait parameters and functional balance in chronic stroke patients

[Purpose] Observational study investigating the influence of various ankle-foot orthoses on the spatiotemporal gait parameters and functional balance in chronic stroke patients. [Subjects and Methods] Fifteen chronic stroke patients participated in this study after providing informed consent. Two groups of patients were differentiated based on the Timed Up and Go Test. Patients were tested in three different conditions: with standard prefabricated ankle-foot orthosis (Maramed), with individualized ankle-foot orthosis (Y-tech), and without any ankle-foot orthrosis. Spatiotemporal gait parameters were obtained by walking on an instrumented walkway (GAITRite(®)) at usual and fastest speed. Balance was assessed with Timed Up and Go Test, Step Test, and Four Square Step Test. [Results] Maramed and Y-tech significantly improved the spatiotemporal parameters while walking at usual and maximal speed (single support time affected side; double support time affected side and step length unaffected side). The Y-tech in addition improved velocity and cadence. Among the balance tests, only the Timed Up and Go test showed improvements in favor of Maramed and Y-tech. [Conclusion] Patients benefited from wearing orthosis at both usual and maximal speed, irrespective of whether they wore Maramed or Y-tech. Only severe stroke patients benefited from wearing an orthoses compared to mild impaired group.

Effects of the ankle angle of an ankle foot orthosis on foot pressure during the gait in healthy adults

[Purpose] The purpose of this study was to investigate the effects of the ankle angle of an ankle foot orthosis (AFO) on foot pressure during the gait in healthy adults. [Subjects] Sixteen healthy males with neither orthopedic nor neurological problems participated in this study. [Methods] Subjects walked on a walkway at a self-selected pace with an AFO set at four different ankle angles (−5°, 0°, 5°, and 10°). Foot pressure was measured randomly according to the ankle angle of the AFO using an F-scan system. Three trials were measured and averaged for data analysis. [Results] The peak foot pressure of the hallux, 2nd–5th toes, 2nd and 3rd metatarsal heads, 4th and 5th metatarsal heads, and the heel showed significant differences among the AFO ankle angles: angles of 0° and −5° increased the foot pressure of the lateral legions, and the peak foot pressure of the heel at an AFO ankle angle of 10° was significantly greater than those of the other angles. [Conclusion] The ankle angle of the AFO affected foot pressure and gait patterns during gait. The results suggest that the appropriate angle for an AFO is between 5° and 10° when AFOs are prescribed by clinicians.

Effects of a functional foot orthosis on the knee angle in the sagittal plane of college students in their 20s with flatfoot

[Purpose] The purpose of this study was to examine the effects of a functional foot orthosis on the knee angle in the sagittal plane of college students in their 20s who had flatfoot. [Subjects and Methods] The subjects of this study were 20 college students diagnosed as having flatfoot. The variations of their knee angle (Q-angle) in the sagittal plane during the stance phase were measured using the VICON Motion System (Vicon, Hansung, Korea) before and while wearing a foot orthosis. The experimental data were analyzed using SPSS 12.0 for Windows. [Results] The Q-angle in the test group during the stance phase showed statistically significant declines on the right and left sides while wearing the foot orthosis during the gait-phases of loading response and midstance. During initial contact, terminal stance, and preswing, the Q-angle also decreased on the right and left sides after wearing the foot orthosis, but the changes were not statistically significant. [Conclusion] The college students with flatfoot exhibited declines in the Q-angle in the sagittal plane while wearing a foot orthosis. In this regard, the application of active gait training using orthotic shoes for long hours is likely to help individuals with flatfoot to achieve normal gait.

The effects of foot orthosis on the gait ability of college students in their 20s with flat feet

[Purpose] This study examined the effects of foot orthosis on the gait ability of college students in their 20s with flat feet. [Subjects and Methods] The subjects were 20 college students who had been diagnosed with flat feet. The subjects’ step time, step length, stride time, stride length, and gait velocity were measured using the VICON Motion System (Vicon, Oxford, UK) prior to and while wearing foot orthoses. The resulting data were analyzed using SPSS v. 12.0. [Results] The subject’s step time and stride time significantly decreased for both feet after they began using foot orthosis, and stride length and gait velocity significantly increased in both feet orthosis; however, step length did not significantly increase on either side. [Conclusions] College students with flat feet saw an improvement in elements of their gait while using the foot orthosis. The results of this study verified that students with flat feet might walk more efficiently if they received active gait training via long-term use of foot orthosis.