Relationships between sensory stimuli and autonomic nervous regulation during real and virtual exercises

<p>Abstract</p> <p>Background</p> <p>Application of virtual environment (VE) technology to motor rehabilitation increases the number of possible rehabilitation tasks and/or exercises. However, enhancing a specific sensory stimulus sometimes causes unpleasant sensations or fatigue, which would in turn decrease motivation for continuous rehabilitation. To select appropriate tasks and/or exercises for individuals, evaluation of physical activity during recovery is necessary, particularly the changes in the relationship between autonomic nervous activity (ANA) and sensory stimuli.</p> <p>Methods</p> <p>We estimated the ANA from the R-R interval time series of electrocardiogram and incoming sensory stimuli that would activate the ANA. For experiments in real exercise, we measured vehicle data and electromyogram signals during cycling exercise. For experiments in virtual exercise, we measured eye movement in relation to image motion vectors while the subject was viewing a mountain-bike video image from a first-person viewpoint.</p> <p>Results</p> <p>For the real cycling exercise, the results were categorized into four groups by evaluating muscle fatigue in relation to the ANA. They suggested that fatigue should be evaluated on the basis of not only muscle activity but also autonomic nervous regulation after exercise. For the virtual exercise, the ANA-related conditions revealed a remarkable time distribution of trigger points that would change eye movement and evoke unpleasant sensations.</p> <p>Conclusion</p> <p>For expanding the options of motor rehabilitation using VE technology, approaches need to be developed for simultaneously monitoring and separately evaluating the activation of autonomic nervous regulation in relation to neuromuscular and sensory systems with different time scales.</p

Personal customizing exercise with a wearable measurement and control unit

BACKGROUND: Recently, wearable technology has been used in various health-related fields to develop advanced monitoring solutions. However, the monitoring function alone cannot meet all the requirements of customizing machine-based exercise on an individual basis by relying on biosignal-based controls. We propose a new wearable unit design equipped with measurement and control functions to support the customization process. METHODS: The wearable unit can measure the heart rate and electromyogram signals during exercise performance and output workload control commands to the exercise machines. The workload is continuously tracked with exercise programs set according to personally customized workload patterns and estimation results from the measured biosignals by a fuzzy control method. Exercise programs are adapted by relying on a computer workstation, which communicates with the wearable unit via wireless connections. A prototype of the wearable unit was tested together with an Internet-based cycle ergometer system to demonstrate that it is possible to customize exercise on an individual basis. RESULTS: We tested the wearable unit in nine people to assess its suitability to control cycle ergometer exercise. The results confirmed that the unit could successfully control the ergometer workload and continuously support gradual changes in physical activities. CONCLUSION: The design of wearable units equipped with measurement and control functions is an important step towards establishing a convenient and continuously supported wellness environment

Sensation of presence and cybersickness in applications of virtual reality for advanced rehabilitation

Around three years ago, in the special issue on augmented and virtual reality in rehabilitation, the topics of simulator sickness was briefly discussed in relation to vestibular rehabilitation. Simulator sickness with virtual reality applications have also been referred to as visually induced motion sickness or cybersickness. Recently, study on cybersickness has been reported in entertainment, training, game, and medical environment in several journals. Virtual stimuli can enlarge sensation of presence, but they sometimes also evoke unpleasant sensation. In order to safely apply augmented and virtual reality for long-term rehabilitation treatment, sensation of presence and cybersickness should be appropriately controlled. This issue presents the results of five studies conducted to evaluate visually-induced effects and speculate influences of virtual rehabilitation. In particular, the influence of visual and vestibular stimuli on cardiovascular responses are reported in terms of academic contribution

Long-term observation of fibrillation cycle length in patients under angiotensin II receptor blocker therapy for chronic atrial fibrillation

AbstractIntroductionThe long-term effect of angiotensin II receptor blockers (ARBs) on atrial fibrillation (AF) is unclear. In this study, we evaluated the change in the fibrillation cycle length (FCL) in patients under long-term ARB therapy for chronic AF.Methods and resultsThe study population consisted of 25 chronic AF patients who were prescribed the same medication for more than 6 years and in whom specific ECG recording for FCL evaluation could be performed before and after the 6-year observation period. The patients were divided into 2 groups: those with and without ARB (ARB group and non-ARB group and n=15 and 10, respectively). FCL was calculated by the spectral analysis of the fibrillation waves in the surface ECG. There was no significant difference in the clinical characteristics between the 2 groups. In the ARB group, the mean FCL was prolonged from 154±20ms to 187±37ms (p=0.005), whereas it remained unchanged in the non-ARB group (150±12ms vs. 149±10ms). In the comparison between patients with and those without FCL prolongation (>30ms; n=6 and 19, respectively), a significant difference was observed only in those prescribed ARBs.ConclusionIn cases of chronic AF, FCL might be prolonged under long-term ARB treatment