Feedback Type May Change the EMG Pattern and Kinematics During Robot Supported Upper Limb Reaching Task.

Haptic interfaces and virtual reality (VR) technology have been increasingly introduced in rehabilitation, facilitating the provision of various feedback and task conditions. However, correspondence between the feedback/task conditions and movement strategy during reaching tasks remains a question. To investigate movement strategy, we assessed velocity parameters and peak latency of electromyography. Ten neuromuscularly intact volunteers participated in the measurement using haptic interface and VR. Concurrent visual feedback and various terminal feedback (e.g., visual, haptic, visual and haptic) were given. Additionally, the object size for the reaching task was changed. The results demonstrated terminal haptic feedback had a significant impact on kinematic parameters; showed [Formula: see text] s ([Formula: see text]) shorter movement time and [Formula: see text] m/s ([Formula: see text]) higher mean velocity compared to no terminal feedback. Also, smaller peak latency was observed in different muscle regions based on the object size.

The size and behavior of virtual objects have influence on functional exercise and motivation of persons with multiple sclerosis: a randomized study.

The consequences of multiple sclerosis are problems with limb movement, coordination, and vision. Heretofore a combination of therapy and additional medications can alter the course of the disease and reduce upper extremity disability. We developed a virtual environment for pick-and-place tasks as a supportive tool to address the problem of challenging task in occupational therapy. The primary objective of the study was to investigate the influence of size and bounce on proximal and fine motor performance and intrinsic motivation. The secondary objective was to examine how the absence of challenge may decrease intrinsic motivation and heart rate. The randomized trial involved 84/107 eligible inpatients with multiple sclerosis. They were divided into 4 groups by computer randomization: Group 1 small and bouncing, Group 2 small and non-bouncing, Group 3 large and bouncing, and Group 4 large and non-bouncing virtual cubes. Each participant completed 50 sessions of up to 2 min each in approximately 14 days. Before commencement of the study the participants completed visuospatial and cognitive tests. Participants' subjective experiences were assessed daily using the intrinsic motivation inventory. Before and after the study, the box and block test and the 9-hole peg test were administered. Kinematic analysis showed significant differences between groups (average manipulation time p = 0.008, inserted cubes p = 0.004). Group 4 was the most successful (inserted cubes > 9) and the fastest (63.4 SD 25.8 s), but had low pressure/tension and heart rate. Group 1 was the slowest (88.9 SD 28.2 s) but had increased interest/enjoyment in the task under higher pressure/tension. There were substantial differences in intrinsic motivation between the 1st and last sessions within groups (Cohen's U3 < 0.3 or > 0.8). The size and behavior of virtual objects may be important for training proximal movements and fine motor skills in people with multiple sclerosis. Furthermore, the demonstrated approach proved to be effective and may reduce upper extremity disability in the long term if intrinsic motivation can be sustained longer with a challenging task.Trial registration The small scale randomized pilot trial has been registered at ClinicalTrials.gov Identifier: NCT04266444, 12/02/2020, https://clinicaltrials.gov/ct2/show/NCT04266444 .

Exergaming as Part of the Telerehabilitation Can Be Adequate to the Outpatient Training: Preliminary Findings of a Non-randomized Pilot Study in Parkinson's Disease.

Parkinson's disease is a long-term and progressive degenerative disorder of the nervous system, affecting primarily motor coordination, noticeable as a tremor in one hand. Recent studies reported on positive outcomes of intensive physiotherapy of upper extremities. We built a telerehabilitation system with virtual pick and place tasks for small scale hand movements, and designed a pilot study to find whether such exergaming as a telerehabilitation service provides comparable outcomes as an outpatient exergaming service. A non-randomized pilot trial was designed. Hospital outpatients (28/40) with Parkinson's disease were recruited. Those meeting the inclusion criteria were divided into two groups; seven outpatients were assigned to the home (H) group and 21 outpatients to the hospital (URI) group. Both groups received 10 days of exergaming over the course of 2 weeks, each daily session lasting a maximum of 1 h. Primary outcomes were clinical tests; Box and Blocks Test (BBT), Jebsen Hand Function Test (JHFT), and Unified Parkinson's Disease Rating Scale (UPDRS part III) were carried out before and after the study. Secondary outcomes were hand kinematics and exergaming results; number of successfully moved objects and task time. Statistical analysis was carried out to find significant (p < 0.05) differences and Cohen's U3 was used to determine effect sizes. The differences between the groups in gender (p = 0.781), age (p = 0.192), and duration of the disease (p = 0.195) were tested with Bartlett's test and no statistical differences were found with an F test. Both groups demonstrated statistically significant improvements in clinical test UDPRS III (p = 0.006 and p = 0.011) and the hospital group also in BBT (p = 0.002) and JHFT (p = 0.015) and with UDPRS III and JHFT even in favor of the home group (χ2 = 5.08, p = 0.024, χ2 = 7.76, p = 0.005). Nevertheless, the exergaming results show significant improvement after training (U3 > 0.86). Exergaming has already been suggested as an effective approach in the planning of rehabilitation tasks for persons with Parkinson's disease. We have prepared a pilot study demonstrating that exergaming at home with telerehabilitation support may provide comparable clinical outcomes. The study shall be followed by a randomized study with higher statistical power to provide clinical evidence. Nevertheless, carrying out even part of the rehabilitation program at home is crucial for the development of future telerehabilition clinical services. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03175107.

High-density electromyography biofeedback during robotic wrist exercises for reducing co-activation of antagonist muscles: a case report.

High-density (HD) electrodes have been introduced in research and diagnostic electromyography. Recent advances in technology offer an opportunity for using the HDEMG signal as biofeedback in stroke rehabilitation. The purpose of this case study was to test the feasibility of using two 5 × 13 electrode arrays for providing real-time HDEMG biofeedback and the preliminary outcome of combining HDEMG biofeedback with robotic wrist exercises over 4 weeks in a person who suffered a stroke 26 months earlier. The isometric wrist flexion/extension task required to keep the paretic agonist activity within variable preset limits with minimal activation of the antagonists. The participant was able to utilize the provided biofeedback interface and after eight sessions significantly decreased co-activation in the antagonist wrist extensor muscles during isometric wrist flexion. The HDEMG biofeedback seems feasible and may be used alone or in combination with robotic therapy for increasing the selectivity of muscle activation after stroke.

Movement strategy and EMG activities of the upper extremity at assisted reaching exercise with a 7 DOF collaborative robot.

Recovering of upper extremity functions is important for stroke patients to perform various tasks in daily life. For better rehabilitation outcomes and accurate measurement, robot assisted exercises have been developed. However, there are limited number of studies related to arm muscles activities corresponding to task complexity. We conducted a preliminary case study on strategy and activities of upper extremity muscles in a healthy volunteer at reaching exercise with haptic feedback by a robot with seven degree-of-freedom when a different target was presented in the virtual environment. Impedance control for Franka Emika Panda robot arm has been developed. The study protocol consisted of 4 sets of 40 reaching trials. The trials had two modes with two different feedback: big target task mode and the small target task mode. In each mode both options, with/without haptic feedback were tested. The preliminary results suggest that different distance to target and target's size is related to the change of activation order and intensity of muscle activities at reaching task. Additionally, the haptic feedback required different activation order and higher intensity regardless of the task difficulty.

Multi-Exergames to Set Targets and Supplement the Intensified Conventional Balance Training in Patients With Stroke: A Randomized Pilot Trial.

People who survive a stroke usually suffer movement disorders resulting in involuntary abnormal movements. Intensive and repetitive physiotherapy is often a key to functional restoration of movements. Rehabilitation centers have recently offered balance training supported by exergames in addition to conventional therapy. The primary objective was to investigate different types of balance training (multi-exergaming and conventional) in addition to a conventional 6-week physiotherapy program. Furthermore, we examined the choice of an appropriate exergame to target balance training. We designed a randomized pilot trial. Hospital inpatients with stroke aged 33-65 were recruited and randomized into 2 groups by drawing lots; a control group receiving 1 week of conventional balance training and an exergaming group 1 week of multiple-game exergaming, comprising single leg exercises, weight shifting, balancing and standing up. Center of pressure was monitored for the exergaming group and clinical data were collected (non-blinded assessment) using Four Square Step Test, Timed Up and Go, 10 m Walk Test, Romberg, Sharpened Romberg, Clinical Test for Sensory Interaction in Balance in both groups. Statistical tests were used to find significant (p < 0.05) differences and Cohen's U3 for effect sizes. Recruited participants (20/30) met the inclusion criteria and were randomized; 10 per group. 1 participant of the exergaming group was excluded from center of pressure analysis. Both groups demonstrated substantively and statistically significant improvements of functional balance, in particular the exergaming group (FSST p = 0.009, U3 = 0.9 and 10 MWT p = 0.008, U3 = 0.9). However, significant differences between the groups were found in tests with eyes closed, Sharpened Romberg test (p = 0.05) and standing on the right leg (p = 0.035). The center of pressure area decreased up to 20% for the exergaming group. Both types of additional balance training demonstrated comparable outcomes, however, the multi-exergaming could target specific motor control disorders by the selection of exergames according to Gentile's taxonomy. We may not prioritize exergaming due to the low statistical power of clinical outcomes. However, exergaming enables independent balance training, which is feasible without strenuous physiotherapy and may thus be crucial for future home or telerehabilitation services. Clinical Trial Registration: www.clinicaltrials.gov/, identifier NCT03282968.

Estimation of Muscle Co-Activations in Wrist Rehabilitation After Stroke is Sensitive to Motor Unit Distribution and Action Potential Shapes.

We evaluated different muscle excitation estimation techniques, and their sensitivity to Motor Unit (MU) distribution in muscle tissue. For this purpose, the Convolution Kernel Compensation (CKC) method was used to identify the MU spike trains from High-Density ElectroMyoGrams (HDEMG). Afterwards, Cumulative MU Spike Train (CST) was calculated by summing up the identified MU spike trains. Muscle excitation estimation from CST was compared to the recently introduced Cumulative Motor Unit Activity Index (CAI) and classically used Root-Mean-Square (RMS) amplitude envelop of EMG. To emphasize their dependence on the MU distribution further, all three muscle excitation estimates were used to calculate the agonist-antagonist co-activation index. We showed on synthetic HDEMG that RMS envelopes are the most sensitive to MU distribution (10 % dispersion around the real value), followed by the CST (7 % dispersion) and CAI (5 % dispersion). In experimental HDEMG from wrist extensors and flexors of post-stroke subjects, RMS envelopes yielded significantly smaller excitations of antagonistic muscles than CST and CAI. As a result, RMS-based co-activation estimates differed significantly from the ones produced by CST and CAI, illuminating the problem of large diversity of muscle excitation estimates when multiple muscles are studied in pathological conditions. Similar results were also observed in experimental HDEMG of six intact young males.

Movement analysis of pick-and-place virtual reality exergaming in patients with Parkinson's disease.

BACKGROUND: Reduced coordination of precise small movements of the hand, wrist and fingers in Parkinson's disease (PD) has been mostly solved by medications and deep brain stimulation. The effects have been evaluated by clinical tests only. OBJECTIVE: Virtual reality-based exergaming may enhance fine movements, decrease the medications dosage and provide an additional non-subjective evaluation. METHODS: 3D pick-and-place task (10Cubes) has been developed in a virtual world. The person placed the virtual cubes by the virtual hand, an avatar of the real hand tracked by a Leap Motion Controller (LMC). The system computed the time of manipulating the cube, the total time, the average time, the speed, and the distance. It counted and managed the number of cubes touched, and calculated the hand shake level, i.e. the average tremor index. A pilot test was carried out in a healthy neurologically intact person and a patient with PD using a 3D head-mounted device (HMD) or LCD screen. RESULTS: The results indicate that substantial and also statistically significant (p< 0.05) differences exist between both participants in all objective parameters; the most noteworthy is the average tremor index. However, we found the parameters only marginally different with 2D equipment. CONCLUSIONS: The evaluation system of 10Cubes has proved applicable at an unchanged medication plan, but its clinical effectiveness could be confirmed with a randomized study.

Advantages of using 3D virtual reality based training in persons with Parkinson's disease: a parallel study.

BACKGROUND: Parkinson's disease (PD) is a slowly progressive neurodegenerative disease. There are mixed reports on success of physiotherapy in patients with PD. Our objective was to investigate the functional improvements, motivation aspects and clinical effectiveness when using immersive 3D virtual reality versus non-immersive 2D exergaming. METHODS: We designed a randomized parallel study with 97 patients, but only 20 eligible participants were randomized in 2 groups; the one using 3D Oculus Rift CV1 and the other using a laptop. Both groups participated in the 10-session 3 weeks training with a pick and place task in the virtual world requiring precise hand movement to manipulate the virtual cubes. The kinematics of the hand was traced with Leap motion controller, motivation effect was assessed with modified Intrinsic Motivation Inventory and clinical effectiveness was evaluated with Box & Blocks Test (BBT) and shortened Unified Parkinson's disease rating scale (UPDRS) before and after the training. Mack-Skilling non-parametrical statistical test was used to identify statistically significant differences (p < 0.05) and Cohen's U3 test to find the effect sizes. RESULTS: Participants in the 3D group demonstrated statistically significant and substantially better performance in average time of manipulation (group x time, p = 0.009), number of successfully placed cubes (group x time, p = 0.028), average tremor (group x time, p = 0.002) and UPDRS for upper limb (U3 = 0.35). The LCD and 3D groups substantially improved their BBT score with training (U3 = 0.7, U3 = 0.6, respectively). However, there were no statistically significant differences in clinical tests between the groups (group x time, p = 0.2189, p = 0.2850, respectively). In addition the LCD group significantly decreased the pressure/tension (U3 = 0.3), the 3D did not show changes (U3 = 0.5) and the differences between the groups were statistically different (p = 0.037). The 3D group demonstrated important increase in effort (U3 = 0.75) and perceived competences (U3 = 0.9). CONCLUSIONS: The outcomes of the study demonstrated that the immersive 3D technology may bring increased interests/enjoyment score resulting in faster and more efficient functional performance. But the 2D technology demonstrated lower pressure/tension score providing similar clinical progress. A study with much larger sample size may also confirm the clinical effectiveness of the approaches. TRIAL REGISTRATION: The small scale randomized pilot study has been registered at ClinicalTrials.gov Identifier: NCT03515746 , 4 May 2018.

Pilot Long-term Evaluation of Competitive and Cooperative Exercise Games in Inpatient Stroke Rehabilitation.

Interpersonal rehabilitation games, which allow patients to compete or cooperate with other patients or unimpaired loved ones, have demonstrated promising short-term results, but have not yet been tested in longer-term studies. This paper thus presents a preliminary 9-session evaluation of interpersonal rehabilitation games for post-stroke arm exercise. Two pairs of stroke survivors were provided with a system that included one competitive and one cooperative rehabilitation game, and exercised with it for 9 sessions in addition to their conventional therapy. They were able to choose the game they wanted to play in each session, and had to exercise for at least 10 minutes per session. Both pairs completed the protocol without any issues, reporting high levels of motivation and consistent levels of exercise intensity (measured using inertial sensors) across the sessions. Furthermore, the maximum difficulty levels reached in the cooperative game increased over time, and improvements of 1-8 points were observed on the Box and Block test. These results indicate that 2 different interpersonal games are sufficient to promote high levels of motivation and exercise intensity for 9 sessions performed over a 3-week period. As the next step, our system will be expanded with additional competitive, cooperative and single-player games, then tested in full clinical trials in both clinical and home environments.

Comparison of Convolutive Kernel Compensation and Non-Negative Matrix Factorization of Surface Electromyograms.

We compared non-negative matrix factorization (NMF) and convolution kernel compensation techniques for high-density electromyogram decomposition. The experimental data were recorded from nine healthy persons during controlled single degree of freedom (DOF) wrist flexion-extension, supination-pronation, and ulnar-radial deviation movements. We assembled the identified motor units and NMF components into three groups. Those active mostly during the first and the second movement direction per DOF were placed in the G1 and G3 groups, respectively. The remaining components were nonspecific for movement direction and were placed in the G2 group. In ulnar and radial deviation, the relative energies of identified cumulative motor unit spike trains (CSTs) and NMF components were similarly distributed among the groups. In other two movement types, the energy of NMF components in the G2 group was significantly larger than the energy of CSTs. We further performed a coherence analysis between CSTs and sums of NMF components in each group. Both decompositions demonstrated a solid match, but only at frequencies <3 Hz. At higher frequencies, the coherence hardly exceeded the value of 0.5. Potential reasons for these discrepancies include the negative impact of motor unit action potential shapes and noise on NMF decomposition.

Can telerehabilitation games lead to functional improvement of upper extremities in individuals with Parkinson's disease?

Parkinson's disease (PD) is treated by medication, less with deep brain stimulation and physiotherapy. Different opinions on the clinical meaningfulness of the physiotherapy or recommended intensive physiotherapy were found. Our objectives were to design intensive target-based physiotherapy for upper extremities suitable for telerehabilitation services and examine the clinical meaningfulness of the exergaming at an unchanged medication plan. A telerehabilitation exergaming system using the Kinect sensor was developed; 28 patients with PD participated in the study. The system followed the participants' movements and adapted the difficulty level of the game in real time. The outcomes of the study showed that seven out of 26 participants could set up the equipment at home alone. Clinical outcomes of Box and Blocks Test (mean: 47 vs. 52, P=0.002, Cohen's d=0.40), UPDRS III (mean: 27 vs. 29, P=0.001, d=0.22), and daily activity Jebsen's test; writing a letter (mean: 24.0 vs. 20.6, P=0.003, d=0.23); and moving light objects (mean: 4.4 vs. 3.9, P=0.006, d=0.46) were statistically significant (P<0.05) and considered clinically meaningful. The Nine-Hole Peg Test showed a statistically nonsignificant improvement (mean: 28.0 vs. 26.5, P=0.089, d=0.22). The participants claimed problems with mobility but less with activities of daily living and emotional well-being (PDQ-39). The findings lead to preliminary conclusions that exergaming is feasible, but may require technical assistance, whereas clinically meaningful results could be achieved according to validated instruments and an unchanged medication plan in individuals with PD.

A multisession evaluation of an adaptive competitive arm rehabilitation game.

BACKGROUND: People with neurological injuries such as stroke should exercise frequently and intensely to regain their motor abilities, but are generally hindered by lack of motivation. One way to increase motivation in rehabilitation is through competitive exercises, but such exercises have only been tested in single brief sessions and usually did not adapt difficulty to the patient's abilities. METHODS: We designed a competitive arm rehabilitation game for two players that dynamically adapts its difficulty to both players' abilities. This game was evaluated by two participant groups: 15 participants with chronic arm impairment who exercised at home with an unimpaired friend or relative, and 20 participants in the acute or subacute phase of stroke who exercised in pairs (10 pairs) at a rehabilitation clinic. All participants first played the game against their human opponent for 3 sessions, then played alone (against a computer opponent) in the final, fourth session. In all sessions, participants' subjective experiences were assessed with the Intrinsic Motivation Inventory questionnaire while exercise intensity was measured using inertial sensors built into the rehabilitation device. After the fourth session, a final brief questionnaire was used to compare competition and exercising alone. RESULTS: Participants who played against an unimpaired friend or relative at home tended to prefer competition (only 1 preferred exercising alone), and exhibited higher enjoyment and exercise intensity when competing (first three sessions) than when exercising alone (last session). Participants who played against each other in the clinic, however, did not exhibit significant differences between competition and exercising alone. For both groups, there was no difference in enjoyment or exercise intensity between the first three sessions, indicating no negative effects of habituation or novelty. CONCLUSIONS: Competitive exercises have high potential for unsupervised home rehabilitation, as they improve enjoyment and exercise intensity compared to exercising alone. Such exercises could thus improve rehabilitation outcome, but this needs to be tested in long-term clinical trials. It is not clear why participants who competed against each other at the clinic did not exhibit any advantages of competition, and further studies are needed to determine how different factors (environment, nature of opponent etc.) influence patients' experiences with competitive exercises. TRIAL REGISTRATION: The study is not a clinical trial. While human subjects are involved, they do not participate in a full rehabilitation intervention, and no health outcomes are examined.

A Cloud-Based Virtual Reality App for a Novel Telemindfulness Service: Rationale, Design and Feasibility Evaluation.

BACKGROUND: Worldwide, there has been a marked increase in stress and anxiety, also among patients with traumatic brain injury (TBI). Access to psychology services is limited, with some estimates suggesting that over 50% of sufferers are not accessing the existing services available to them for reasons such as inconvenience, embarrassment, or stigmatization concerns around mental health. Health service providers have increasingly been turning to drug-free therapies, such as mindfulness programs, as complementary treatments. OBJECTIVE: Virtual reality (VR) as a new delivery method for meditation-based stress and anxiety reduction therapy offers configurable environments and privacy protection. Our objective was to design a serious learning-meditation environment and to test the feasibility of the developed telemindfulness approach based on cloud technologies. METHODS: We developed a cloud-based system, which consisted of a Web interface for the mindfulness instructor and remote clients, who had 3D VR headsets. The mindfulness instructor could communicate over the Web interface with the participants using the headset. Additionally, the Web app enabled group sessions in virtual rooms, 360-degree videos, and real interactions or standalone meditation. The mindfulness program was designed as an 8-week Mindfulness-Based Stress Reduction course specifically for the developed virtual environments. The program was tested with four employees and four patients with TBI. The effects were measured with psychometric tests, the Mindful Attention Awareness Scale (MAAS) and the Satisfaction With Life Scale (SWLS). Patients also carried out the Mini-Mental State Examination (MMSE). An additional objective evaluation has also been carried out by tracking head motion. Additionally, the power spectrum analyses of similar tasks between sessions were tested. RESULTS: The patients achieved a higher level of life satisfaction during the study (SWLS: mean 23.0, SD 1.8 vs mean 18.3, SD 3.9) and a slight increase of the MAAS score (mean 3.4, SD 0.6 vs mean 3.3, SD 0.4). Particular insight into the MAAS items revealed that one patient had a lower MAAS score (mean 2.3). Employees showed high MAAS scores (mean 4.3, SD 0.7) and although their SWLS dropped to mean 26, their SWLS was still high (mean 27.3, SD 2.8). The power spectrum showed that the employees had a considerable reduction in high-frequency movements less than 0.34 Hz, particularly with the 360-degree video. As expected, the patients demonstrated a gradual decrease of high-frequency movements while sitting during the mindfulness practices in the virtual environment. CONCLUSIONS: With such a small sample size, it is too early to make any specific conclusions, but the presented results may accelerate the use of innovative technologies and challenge new ideas in research and development in the field of mindfulness/telemindfulness.

Competitive and cooperative arm rehabilitation games played by a patient and unimpaired person: effects on motivation and exercise intensity.

BACKGROUND: People with chronic arm impairment should exercise intensely to regain their abilities, but frequently lack motivation, leading to poor rehabilitation outcome. One promising way to increase motivation is through interpersonal rehabilitation games, which allow patients to compete or cooperate together with other people. However, such games have mainly been evaluated with unimpaired subjects, and little is known about how they affect motivation and exercise intensity in people with chronic arm impairment. METHODS: We designed four different arm rehabilitation games that are played by a person with arm impairment and their unimpaired friend, relative or occupational therapist. One is a competitive game (both people compete against each other), two are cooperative games (both people work together against the computer) and one is a single-player game (played only by the impaired person against the computer). The games were played by 29 participants with chronic arm impairment, of which 19 were accompanied by their friend or relative and 10 were accompanied by their occupational therapist. Each participant played all four games within a single session. Participants' subjective experience was quantified using the Intrinsic Motivation Inventory questionnaire after each game, as well as a final questionnaire about game preferences. Their exercise intensity was quantified using wearable inertial sensors that measured hand velocity in each game. RESULTS: Of the 29 impaired participants, 12 chose the competitive game as their favorite, 12 chose a cooperative game, and 5 preferred to exercise alone. Participants who chose the competitive game as their favorite showed increased motivation and exercise intensity in that game compared to other games. Participants who chose a cooperative game as their favorite also showed increased motivation in cooperative games, but not increased exercise intensity. CONCLUSIONS: Since both motivation and intensity are positively correlated with rehabilitation outcome, competitive games have high potential to lead to functional improvement and increased quality of life for patients compared to conventional rehabilitation exercises. Cooperative games do not increase exercise intensity, but could still increase motivation of patients who do not enjoy competition. However, such games need to be tested in longer, multisession studies to determine whether the observed increases in motivation and exercise intensity persist over a longer period of time and whether they positively affect rehabilitation outcome. TRIAL REGISTRATION: The study is not a clinical trial. While human subjects are involved, they participate in a single-session evaluation of a rehabilitation game rather than a full rehabilitation intervention, and no health outcomes are examined.

The effects of different types of ankle-foot orthoses on postural responses in individuals with walking impairments.

The aim of this study was to examine the immediate and long-term effects of different ankle-foot orthosis (AFO) types on postural responses in patients with various pathological conditions who, because of their walking disorders, wore an AFO. A total of 37 patients with different pathological conditions who visited the outpatient clinic for orthotics because of walking problems, already used or were referred for an AFO and had no other impairments that may influence balance were included in the study. The participants were divided into four groups according to the type of AFO that they wore. The postural responses were assessed with and without AFO using two force-plates following perturbations in different directions at the level of the pelvis. The centre of pressure was examined in the sagittal and frontal plane and compared with the normative data from healthy individuals. The results showed an improvement in postural responses to the lateral and backward perturbation directions when wearing the AFO, particularly responses in the anterior-posterior direction. The best results were achieved with the custom-made posterior leaf spring AFO for correction of equinovarus deformity. The time of wearing the AFO had an impact on postural responses in perturbation directions where the patients could not rely only on AFO. The custom-made AFO improved overall postural responses, especially dynamic stability, in lateral directions, whereas all stiff AFOs contributed towards an improvement in responses to all perturbations to the affected side. Results showed that long-term use of an AFO can be important for the overall improvement of postural responses.

Postural responses of young adults to collision in virtual world combined with horizontal translation of haptic floor.

Balance and postural response strategies change when subjects are exposed to horizontal translations of the floor or virtual reality or both. This may impact the balance training strategy and balance capabilities assessment in the future telerehabilitation. In the study 15 neurologically intact volunteers participated. Balance standing frame with virtual reality tasks and our novel haptic floor able to generate horizontal translations were used. The postural responses were measured with center of gravity and muscle electromyography of plantar-dorsiflexors, quadriceps, hamstrings, hip and spine muscles in three scenarios. The results demonstrated that center of gravity and electromyographic activity were comparable; with low latency at translation only, longer latency at combination with virtual reality and long latency when only virtual reality was applied. Soleus and semimembranousis demonstrated lower latency at back-right horizontal translations when virtual reality was present. The outcomes suggests that the postural strategy changes from ankle to ankle-hip strategy with availability of additional sensory systems which may be an important issue for objective balance evaluation in the clinical environment and remote telerehabilitation.

Changes in EMG latencies during balance therapy using enhanced virtual reality with haptic floor.

In the paper a research on enhanced experience of virtual reality supported balance training is presented. Haptic floor, mounted on the dynamic standing frame was used as a biofeedback at collisions in virtual environment. Electromyographic muscle activity of soleus, gastrocnemius, tibialis anterior, semimembranosus, rectus femoris, tensor fasciae latae and erector spinae at the time of onset and recovery of postural perturbation were monitored using surface electrodes. 12 neurologically intact young adults participated in the research study. The main goal was to identify the differences in postural response strategies at collisions in the virtual world w/o haptic feedback. We found more dynamic responses in all subjects when applying haptic floor, especially in the ankle complex, stabilizing the tibia at the onset of perturbation. Choosing different strategies using the haptic floor may significantly enhance the telerehabilitation experience and thus increase the effectivness of the tele-balance training. Besides telerehabilitation, such system may be also effective for postural reponse assessment and thus simplified telediagnostics. However, the findings call for further study to support the proposed proof of concept.