Elevated heart rate is considered to be an indicator of stress. Thus, noticing one’s own heartbeat can have a negative connotation. Yet, the heartbeat is simply a physiological function, neither positive nor negative in itself, that is experienced in diverse contexts, such as medical, athletic, or intimate. This study uses first-person  research through design and soma design to increase awareness of the heartbeat from both an individual and social angle and examines the potential benefits of using external sensory stimuli to convey biofeedback information. It also opens up the design space around the heartbeat and sensory stimuli and reflects upon comfort and relaxation, biofeedback and digital mindfulness, the Sensiks sensory reality pod as a tool and space, and the heartbeat as a spectrum and a way of getting to know people. The study results in four deliverables: a design critique of the Sensiks sensory reality pod, a design fiction publication, a design proposal, and an experience prototype. The study proposes the design for the Gallery of Heartbeats – a sensory experience aimed at externalising and sharing the heartbeat of self and others. The Gallery of Heartbeats supports individual reflections, providing the user with real-time numerical, graphical, and auditory biofeedback on their heart rate. It also encourages social communication of this commonly unnoticed physiological feature, allowing users to record and store their heartbeat to an archive and experience the pre-recorded heartbeats of others in a multisensory way. The evaluation of the Gallery of Heartbeats prototype shows that the design succeeds in making people more aware of their cardiovascular activity, triggers their curiosity, and increases empathy. However, the Gallery of Heartbeats also makes the users want to control or change their heart rate which goes against the mindfulness principles of presence-in and presence-with the design was inspired by. Sensory stimuli, especially sound and visuals, are assessed as beneficial for creating feelings of immersion, whereas different representations of the biofeedback information have different effects and use cases. / En förhöjd hjärtfrekvens anses vara en indikator på stress. Därför kan en hög puls tolkas som något negativt. Likväl har hjärtats pulserande enbart en fysiologisk funktion, som i sig varken har en positiv eller negativ betydelse, och som kan erfaras under olika omständigheter, såsom i medicinska sammanhang, vid fysisk träning eller under intima stunder.  Denna studie är en forskning-genom-design ur ett förstapersonsperspektiv samt soma-design för att öka medvetenheten om sina hjärtslag, både från en individuell och en social vinkel, samt en undersökning av de potentiella fördelar som kan finnas med att använda ett yttre stimuli för att ge biofeedback. Den öppnar också upp designrymden kring hjärtslag och sensorisk stimuli, reflekterar kring välbefinnande och avslappning, biofeedback och digital mindfulness, Sensiks sensoriska kapsel som ett verktyg och en plats, samt hjärtfrekvens som ett spektrum och ett sätt att lära känna människor. Resultatet av studien framställs i fyra olika delar: en designkritik av Sensiks sensoriska kapsel, en fiktiv design publikation, ett designförslag, och en prototyp av upplevelser. Detta examensarbete utmynnar i ett förslag på en design kallad “Gallery of Heartbeats” - en sensorisk upplevelse avsedd att ge en yttre form och för att dela hjärtslagen med sig själv och andra. “Gallery of Heartbeats” skapar utrymme för individuell reflektion, och ger användaren i realtid en numerisk, grafisk och ljudmässig biofeedback på sin hjärtfrekvens. Den uppmuntrar också till samtal av detta vanligtvis omärkbara fysiologiska fenomen, den möjliggör användaren att spela in och spara sina hjärtslag i ett arkiv, och användaren ges möjlighet att uppleva förinspelade hjärtslag av andra personer på ett multisensoriskt sätt. Utvärdering av prototypen för “Gallery of Heartbeats” visar att designen lyckas få människor mer medvetna om sin kardiovaskulära aktivitet, väcker deras nyfikenhet och ökar empatin. Dock gör även “Gallery of Heartbeats” att användaren vill kontrollera eller ändra sin hjärtfrekvens, vilket går emot de principerna inom mindfulness av att vara ‘presence-in’ och ‘presence-with’. Sensorisk stimuli, särskilt ljud och bild, ses som främjande av att skapa känslan av att vara absorberad, medan andra signaler från biofeedback har en annan påverkan och andra användningsområden.

Objective: Restorative sleep is associated with increased autonomous parasympathetic nervous system activity that might be improved by heart rate variability-biofeedback (HRV-BF) training. Hence the aim of this study was to investigate the effect of a four-week mobile HRV-BF intervention on the sleep quality and HRV of healthy adults. - Methods: In a prospective study, 26 healthy participants (11 females; mean age: 26.04 ± 4.52 years; mean body mass index: 23.76 ± 3.91 kg/m²) performed mobile HRV-BF training with 0.1 Hz breathing over four weeks, while sleep quality, actigraphy and HRV were measured before and after the intervention. - Results: Mobile HRV-BF training with 0.1 Hz breathing improved the subjective sleep quality in healthy adults [t(24) = 4.9127, p ≤ 0.001, d = 0.99] as measured by the Pittsburgh Sleep Quality Index. In addition, mobile HRV-BF training with 0.1 Hz breathing was associated with an increase in the time and frequency domain parameters SDNN, Total Power and LF after four weeks of intervention. No effect was found on actigraphy metrics. - Conclusions: Mobile HRV-BF intervention with 0.1 Hz breathing increased the reported subjective sleep quality and may enhance the vagal activity in healthy young adults. HRV-BF training emerges as a promising tool for improving sleep quality and sleep-related symptom severity by means of normalizing an impaired autonomic imbalance during sleep.

Most manual wheelchair users will experience upper extremity injury and pain during their lifetime, which can be partly attributed to the high load requirements, repetitive motions and extreme joint postures required during wheelchair propulsion. Recent efforts have attempted to determine how different propulsion techniques influence upper extremity demand using broad measures of demand (e.g., metabolic cost). However studies using more specific measures (e.g., muscle stress), have greater potential to determine how altering propulsion technique influences demand. The goal of this research was to use a musculoskeletal model with forward dynamics simulations of wheelchair propulsion to determine how altering propulsion technique influences muscle demand. Three studies were performed to achieve this goal. In the first study, a wheelchair propulsion simulation was used with a segment power analysis to identify muscle functional roles. The analysis showed that muscles contributed to either the push (i.e. delivering handrim power) or recovery (i.e. repositioning the hand) subtasks, with the transition period between the subtasks requiring high muscle co-contraction. The high co-contraction suggests that future studies focused on altering transition period biomechanics may have the greatest potential to reduce upper extremity demand. The second study investigated how changing the fraction effective force (i.e. the ratio of the tangential to total handrim force, FEF) influenced muscle demand. Simulations maximizing and minimizing FEF both had higher muscle work and stress relative to the nominal simulation. Therefore, the optimal FEF value appears to balance increasing FEF with minimizing upper extremity demand and care should be taken when using FEF to reduce demand. In the third study, simulations of biofeedback trials were used to determine the influence of cadence, push angle and peak handrim force on muscle demand. Although minimizing peak force had the lowest total muscle stress, individual stresses of many muscles were >20% and the simulation had the highest cadence, suggesting that this variable may not reduce demand. Instead minimizing cadence may be most effective, which had the lowest total muscle work and slowest cadence. These results have important implications for designing effective rehabilitation strategies that can reduce upper extremity injury and pain among manual wheelchair users. / text

Attention deficit hyperactivity disorder (ADHD) is a psychopathology commonly characterized by general inattentiveness and/or a lack of impulse control resulting in hyperactive tendencies. ADHD is estimated to cost the United States roughly $266 billion every year. ADHD is currently treated via medications, cognitive behavioral therapy, or more recently, neurofeedback. Neurofeedback – and biofeedback in general – is the process of providing a patient with information about autonomic bodily functions so that they may control said autonomic function. In the case of ADHD, neurofeedback focuses on reinforcing the behaviors and sensations associated with attentiveness. Currently however, neurofeedback systems are large and require a patient to travel to a clinic. Furthermore, the current offering of portable neuro/biofeedback devices do not have the technological capabilities to provide effective neurofeedback therapy. Current wearable tech devices – such as the Apple Watch and Samsung Gear – possess the technological capabilities to measure important bodily functions, and provide appropriate biofeedback therapy while remaining discrete and most importantly, portable.

Cognitive therapy for the treatment of depression has generated substantial research indicating its effectiveness and it is currently considered among the most viable conceptualizations of depression. However, it has remained controversial because its methods do not directly address emotional symptoms in depressed persons. Treatment of depressed emotions is a primary focus of hypnotic mood elevating techniques. These techniques enable depressed persons to experience positive emotions during hypnosis sessions and to re-experience them daily concurrent with performance of certain specified behaviors. This study evaluated the efficacy of a multicomponent treatment which combines the techniques of cognitive therapy and hypnotic mood elevation in the treatment of depressed persons. The three treatment conditions constructed for this investigation were cognitive therapy plus hypnotic mood elevation, cognitive therapy plus pseudo-biofeedback, and no treatment waiting list.

The forced Oscillation Technique (FOT) can be used to measure lung impedance continuously during breathing. However, spectral overlap between the breathing waveform and the applied flow oscillation can be problematic if the frequency content of spontaneous breathing is unknown. This problem motivated us to develop a modification to the FOT system called the Tracked Breathing Trainer. The modification uses biofeedback to constrain subjects to breathe at a single predetermined frequency. This thesis investigates the engineering and physiological aspects of the modification we made. We studied 8 adult non-asthmatic and 8 adult asthmatic subjects. Three 16 s perturbatory flow oscillation signals ranging from 1-40 Hz were used on the subjects. Each subject received three trials per perturbation for both spontaneous and tracked breathing. We then fitted a resistance-elastance-inertance model of the lung to each data set. For non-asthmatic subjects, the average resistance (R) and elastance (E) values for the first spontaneous breathing trial were 2.5±0.15 cmH2O.s.ml-1 and 18.1±3.55 cmH2O.ml-1, and for the third spontaneous breathing trial were 2.4±0.12 cmH2O.s.ml-1 and 21.8±4 cmH2O.ml-1. R and E for the first tracked breathing trial were 2.3±0.21 cmH2O.s.ml-1 and 33.6±7.4 cmH2O.ml-1, and for the third tracked breathing trial were 2.4±0.14 cmH2O.s.ml-1 and 25.75±4.3 cmH2O.ml-1, respectively. For asthmatic subjects, the average R and E values for the first spontaneous breathing trial were 3.32±0.68 cmH2O.s.ml-1 and 39.13±9.8 cmH2O.ml-1, and for the third spontaneous breathing trial were 3.12±0.15 cmH2O.s.ml-1 and 39.91±6.2 cmH2O.ml-1. R and E for the first tracked breathing trial were 2.86±0.15 cmH2O.s.ml-1 and 32.47±4.1 cmH2O.ml-1, and for the third tracked breathing trial were 2.86±0.21 cmH2O.s.ml-1 and 33.89±10 cmH2O.ml-1, respectively. These results show that R was consistently lower during tracked breathing than spontaneous breathing in both non-asthmatic and asthmatic subjects. However, an increase in E was observed during tracked breathing. We suspect this effect may have resulted from dynamic hyperinflation. These results also show that R and E are reproducible with both spontaneous and tracked breathing, and that R and E were not noticeably different between both breathing maneuvers. We conclude that using biofeedback to control the breathing pattern during application of the FOT in normal subjects does not significantly affect impedance measurements, and thus may be useful for avoiding spectral overlap between FOT perturbations and the breathing pattern.

Respiratory motion poses significant problems in the radiotherapy of tumors located at sites (lung, liver, pancreas, breast) that are affected by such motion. Effects of respiratory motion on the different stages of the radiotherapy process (imaging, treatment planning and treatment delivery), has formed the focus of significant research over the last decade. Results from such research have revealed that respiratory motion affects the instantaneous position of almost all structures in the thorax and abdomen to different degrees based on their corresponding anatomic location and muscular attachments. As an example, diaphragm motion was found to be of the order of 1.5 cm, predominantly in the superior-inferior (SI) direction during normal breathing. This indicates a similar magnitude of motion for tumors located in the lower lobes of the lung and in the abdomen.The conventional method of accounting for such motion is to add a margin (based on an estimate of the expected range of organ motion) around the clinical target volume (CTV) that is delineated from the image data. This margin also includes errors due beam-bony anatomy alignment during radiation delivery and errors in patient position between simulation and subsequent treatment delivery sessions. Such a margin estimate may or may not encompass the "current" extent of motion exhibited by the tumor, resulting in either a higher dose to the surrounding normal tissue or a potential cold spot in the tumor volume. Several clinical studies have reported the existence of a direct relationship between the reduction in mean dose to the lung and the incidence of radiation induced pneumonitis. Therefore, subjecting additional normal lung tissue to high dose radiation by adding large margins based on organ motion estimates may result in an increased risk of radiation induced lung injury.Monitoring and accounting for respiratory motion can however potentate a reduction in the amount of normal tissue that receives high dose radiation, thereby decreasing the probability of normal tissue complication and also increasing the possibility for dose escalation to the actual tumor volume. The management (monitoring and accounting) of respiratory motion during radiation oncology forms the primary theme of this dissertation.Specific aims of this thesis dissertation include (a) identifying the deleterious effects of respiratory motion on conventional radiation therapy techniques (b) examining the different solutions that have been proposed to counter the deleterious effects of respiratory motion during radiotherapy (c) summarizing the relevant work conducted at our institution as part of this thesis in addressing the issue of respiratory motion and (d) visualizing the future direction of research in the management of respiratory motion in radiation oncology.Among the various techniques available to manage respiratory motion in radiation oncology such as respiratory gated and breath hold based radiotherapy, our research initially focused on respiratory gated radiotherapy, employing a commercially available external marker based real time position monitoring system. Multiple session recordings of simultaneous diaphragm motion and external marker motion revealed a consistent linear relationship between the two signals indicating that the external marker motion (along the anterior-posterior (AP) direction) could be used as a "surrogate" for motion of internal anatomy (along the SI direction). The predictability of diaphragm motion based on such external marker motion both within and between treatment sessions was also determined to be of the order of 0.1 cm.Analysis of the parameters that affected the accuracy and efficacy of respiratory gated radiotherapy revealed a direct relationship between the amount of residual motion and the width of the "gate" window. It also followed therefore that a trade-off existed between the width of the "gate" and the accuracy of gated treatments and also the overall "Beam ON" time. Further, gating during exhale was found to be more reproducible than gating during inhale. Although, it was evident that a reduction in the width of the "gate" implied a reduction in the margins added around the clinical target volume (CTV), such a reduction was limited by setup error.A study of the potential gains that could be derived from respiratory gating (based on motion phantom experimental set up) indicated a potential CTV-PTV margin reduction of 0.2-1.1 cm while employing gating alone in combination with an electronic portal imaging device, thus decreasing the amount of healthy tissue receiving radiation. In addition, gating also improved the quality of images obtained during simulation by reducing the amount of motion artifacts that are typically seen during conventional spiral CT imaging.Imparting some form of training was hypothesized to better enable patients to breathe in a reproducible fashion, which was further thought to increase the accuracy and efficacy of gated radiotherapy, especially when the "gate" was set close to the inhale portion of the breathing cycle. An analysis of breathing patterns recorded from five patients over several sessions under conditions of normal quiet breathing, breathing with audio instructions and breathing with visual feedback indicated that training improved the reproducibility of amplitude or frequency of patient breathing cycles.An initial exploration into respiration synchronized radiotherapy was thought to facilitate realization of reduced margins without having to hold the radiation beam delivery during a breathing cycle (as is the case with gating). A feasibility study based on superimposition of respiratory motion of a tumor (simulated by a sinusoidal motion oscillator) onto the initial beam aperture as formed by the multileaf collimator (MLC) revealed that tumor dose measurements obtained with such a set up were equivalent to those delivered to a static tumor by a static beam.Finally, a feasibility study for a method to acquire respiration synchronized images of a motion phantom and a patient (in order to perform respiration synchronized treatment planning and delivery) yielded success in the form of a 4D CT data set with reduced motion artifacts.In summary, respiratory gated radiotherapy and respiration synchronized are both viable approaches to account for respiratory motion during radiotherapy. While respiratory gated radiotherapy has been successfully implemented in some centers, several technical advances are required to enable similar success in the implementation of respiration synchronized radiotherapy. However, the potential clinical gains that can be obtained from either of the above approaches and their relative contributions to margin reduction will determine their future applicability as routine treatment procedures.

Commercial technologies for the objective assessment of balance exist in clinical settings. Training requires integration of sensory information to produce a coordinated motor response related to balance. These systems have had measurable phase delays of up to 250ms in the visual feedback provided to the patient. This provokes an unnatural response, requiring prediction from the subject. The proposed research investigates the impact of visual feedback phase delays on the performance of weight shift tracking tasks in a population of individuals with no known balance deficits.Visual feedback delays were investigated by simulating popular balance training software which utilizes force plates to measure center of pressure and display the results in a stimulus and response study. Ten healthy young-adult subjects with no known balance deficits were recruited to participate in this study. Subjects were asked to stand on a pair of force platforms that were linked to a computer. The system was designed to provide visual feedback corresponding to lateral weight shifts. A computer generated target provided a moving stimulus the subjects attempted to match. The stimulus files presented approximately 20 seconds of movement in a periodic (sinusoidal) or non-periodic pattern. Stimulus frequencies ranged between 0.2 and 1.0 Hz with amplitude sufficient to require the subject to move safely within 50% of his/her base of support. Stimulus presentation was randomized and included both normal (control) and phase delayed (experimental) trials. Results of the experiment point to a noticeable improvement of performance with repeated trials. Regardless of introduced phase delays, study participants improved their performances as they were exposed to more trials, suggesting learning and predictive behavior. Random stimuli produced no noticeable improvements in performance across days of testing, as expected. Visual biofeedback systems may skew performance assessments of balance training because they contain periodic stimuli that are predictable.

Title: An examination of pelvic floor activity following the application of special exercises Objectives: The aim of this thesis is to validate the usefulness of carrying out local pelvic floor muscle examinations as an indication and education for therapy. A second objective is for the women involved in the research to subjectively evaluate the examination methods and therapy. Furthermore, the thesis aims to establish an example of a comprehensive and detailed local examination of the pelvic floor muscles. Methods: We measured the pelvic floor activity per vaginam using an EMG biofeedback device on clients with a pelvic floor dysfunction and grade I stress incontinence symptoms. Based on the results of the examination, therapy using the vaginal device was recommended and in six weeks a follow-up examination was carried out. The changes in pelvic floor activity were evaluated by comparing the initial and follow-up examinations. Thus the usefulness of carrying out an examination of the local pelvic floor muscles before indicating a therapy was validated. At the end of the examination an interview with participating clients was conducted in order to subjectively evaluate the method. Results: All of the women participating in the research had previously undergone a different method of pelvic floor...

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Bibliography: leaf 88. / by Cheryl A. Gira. / B.S.