BackgroundPeople 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.MethodsWe 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.ResultsOf 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.ConclusionsSince 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 registrationThe 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12984-017-0231-4) contains supplementary material, which is available to authorized users.

This paper presents a gait phase detection algorithm for providing feedback in walking with a robotic prosthesis. The algorithm utilizes the output signals of a wearable wireless sensory system incorporating sensorized shoe insoles and inertial measurement units attached to body segments. The principle of detecting transitions between gait phases is based on heuristic threshold rules, dividing a steady-state walking stride into four phases. For the evaluation of the algorithm, experiments with three amputees, walking with the robotic prosthesis and wearable sensors, were performed. Results show a high rate of successful detection for all four phases (the average success rate across all subjects >90%). A comparison of the proposed method to an off-line trained algorithm using hidden Markov models reveals a similar performance achieved without the need for learning dataset acquisition and previous model training.

BackgroundPeople 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.MethodsWe 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.ResultsParticipants 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.ConclusionsCompetitive 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 registrationThe 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.Electronic supplementary materialThe online version of this article (10.1186/s12984-017-0336-9) contains supplementary material, which is available to authorized users.

Previous studies have presented algorithms for detection of turns during gait using wearable sensors, but those algorithms were not built for real-time use. This paper therefore investigates the optimal approach for real-time detection of planned turns during gait using wearable inertial measurement units. Several different sensor positions (head, back and legs) and three different detection criteria (orientation, angular velocity and both) are compared with regard to their ability to correctly detect turn onset. Furthermore, the different sensor positions are compared with regard to their ability to predict the turn direction and amplitude. The evaluation was performed on ten healthy subjects who performed left/right turns at three amplitudes (22, 45 and 90 degrees). Results showed that turn onset can be most accurately detected with sensors on the back and using a combination of orientation and angular velocity. The same setup also gives the best prediction of turn direction and amplitude. Preliminary measurements with a single amputee were also performed and highlighted important differences such as slower turning that need to be taken into account.

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Objective: Competitive exercise games are popular in areas like rehabilitation and weight loss due to their positive effects on motivation. However, it is unclear whether a human opponent is necessary, as the same benefits may be achievable with a ''human-like'' computer-controlled opponent or a human who talks to the player without playing the game. Our objective was to compare four opponent types in a competitive exercise game: a simple computer opponent, ''human-like'' computer opponent, human opponent, and a simple computer opponent accompanied by a player-selected human who chats with the player. Materials and Methods: Sixteen participants (3 women, 24.4 -7.7 years old) played a competitive arm exercise game in the above four conditions. Exercise intensity was measured with inertial sensors, and four motivation scales were measured with the Intrinsic Motivation Inventory. After playing, participants answered several questions regarding their preferences. Results: The human opponent was the favorite for 14 of 16 participants and resulted in the highest interest/ enjoyment and exercise intensity. All participants preferred the human opponent over the computer opponent accompanied by a human companion. Finally, 12 of 16 participants preferred the ''human-like'' computer opponent over the simple one. Conclusion: Our results have two implications for competitive exercise games. First, they indicate that developing computer-controlled opponents with more human-like behavior is worthwhile, but that the best results are achieved with human opponents. Second, social interaction without in-game interaction does not provide an enjoyable, intense experience. However, our results should be verified with different target populations for exercise games.

The goal of our study was the identification of up-regulated genes during axolotl (Ambystoma mexicanum) hindlimb regeneration 4 days after amputation using suppression subtractive hybridization (SSH). Approximately 400 clones that harbored upregulated genes in regenerating blastema tissue were selected for sequence analysis. A BLAST homology search against NCBI non-redundant database and an ambystoma EST database revealed 102 clones that showed homology to known sequences in GenBank with annotated function, 31 were known genes without known function, 74 were novel and 72 belonged to mitochondrial sequences. Differential expression of Hmox1, Orc4L, Pls3, Fen-1, Mcm7 and Mmp3/10a was confirmed using qRT-PCR analysis. Among all genes, only Mmp3/10a has been previously described as involved in limb regeneration. Other important identified genes belong to the group of cell cycle regulators (Orc4L, Nasp, Skp1A and Mcm7, the latter being a possible proliferative marker), those involved in protein synthesis and transport (Sec63, Srp72, Sara2) and V- ATPase pump. The novel genes we identified might be important for the process of blastema formation and the onset of cell proliferation in a regenerating limb.

People with chronic arm impairment should exercise intensely at home after completing their clinical rehabilitation program, but frequently lack motivation. To address this issue, we present a home rehabilitation system that motivates patients by allowing them to perform arm exercises together with friends or relatives in competitive and cooperative games. Inertial sensors are used to track the patient’s arm and control the game. The system was tested with seven adults with arm impairment as well as their friends or spouses. They tested four exercise games (single-player, competitive and two different cooperative games) for 3 minutes each. Of the 7 participants, 4 preferred the competitive game, 2 preferred a cooperative game, and 1 preferred to exercise alone. Competition also increased exercise intensity (measured using inertial sensors) compared to exercising alone. Though preliminary, these results indicate that competitive exercise games could improve arm rehabilitation at home for survivors of neurological and orthopedic injuries.