Medical device landscape for communicable and noncommunicable diseases in low-income countries

Abstract Background This study characterized the landscape of commercially available medical devices specifically designed for use in low-income countries (LICs). Methods A state-of-the-art review of peer-reviewed publications, patents, global health databases, and online resources was performed. The criteria established for a health technology’s inclusion in the study were: it met the definition of a medical device; it was designed and developed to address one of the top ten causes of death in LICs, Millennium Development Goal (MDG) 4, or MDG 5; and there was evidence of its commercialization. Results Analysis identified 134 commercialized devices exclusively designed for use in LICs. More than 85% of devices were designed to address infectious diseases or child or maternal health (MDG 4 or 5, respectively). None of the identified devices addressed prevention of noncommunicable diseases (NCDs). Only 8% of devices were designed for use in primary health facilities by non-physician health providers. Conclusion There is a significant mismatch between the projected global burden of disease due to NCDs and the relevant number of commercialized medical devices designed specifically for use in LICs. A limited number of commercialized devices were designed for use by non-physician health providers. These findings suggest the need for medical devices targeting NCDs in LICs and design processes that consider the broader context of design and engage stakeholders throughout all phases of design.https://deepblue.lib.umich.edu/bitstream/2027.42/144540/1/12992_2018_Article_355.pd

Adaptation of the vestibulo-ocular reflex to head movements during short-radius centrifugation

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.Also available online at the MIT Theses Online homepage .Includes bibliographical references (p. 89-93).Short-radius centrifugation is currently being pursued as a potential countermeasure to long duration space flight. Short-radius centrifugation requires relatively high angular velocities (on the order of 30 rpm) to create centripetal accelerations on the order of 1 g. Unfortunately, out-of-plane head movements during centrifugation induce inappropriate vestibulo-ocular reflexes, debilitating motion sickness symptoms, and illusory tilt sensations due to conflicting visual and vestibular signals. Practical use of an intermittent short-radius centrifuge as a countermeasure requires that crew members be capable of rapidly adapting to the unexpected semicircular canal inputs with minimal side- or post-effects. Furthermore, adaptation not only has to be achieved, it also has to be appropriate for the environment (stationary, rotating, 1 g, or 0 g). The purpose of this research was to investigate humans' ability to attain and maintain adaptation to rotating environments. Subjects participated in a series of pre-/per-/and post-rotation data collection sessions consisting of both eye reflex recordings during head movements, a subjective battery of tests, and autonomic measurements. Eight subjects were tested on three days (D=1, 2, 8). Eye movements were measured in response to out-of-plane head movements during rotation at 23 rpm on-board the MIT short-radius centrifuge (r=2 m). Slow phase eye velocity (SPV) was reconstructed from filtered and de-saccaded eye movement data. The significant main effect of day and pre-/post-adaptation phase demonstrated that normalized SPV decreased following adaptation in the light.by Kathleen Helen Sienko.S.M

Perturbation-based detection and prosthetic correction of vestibulopathic gait

Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, February 2007.Includes bibliographical references.While being able to balance is something most of us take for granted, each year approximately 400,000 Americans are diagnosed with a balance disorder. In order to prevent fall-related injuries due to postural instability, it is important to create both diagnosis techniques so that therapy can be applied before a fall occurs and devices which can aid the balance-impaired population. The aims of this research are twofold: 1) to develop metrics that quantify the locomotor stability of individuals with reduced vestibular function and 2) to assess the capability of a noninvasive vibrotactile balance prosthesis for improving postural and gait stability. The clinical standards of practice for assessing vestibular deficiency include testing postural stability while standing but not during locomotion. This research examines one prospective locomotor-based technique involving the analysis of postural recovery from controlled surface perturbations. The research also investigates the use of a novel wearable vibrotactile sensory substitution device for enhanced postural and locomotor stability. The balance prosthesis is composed of an inertial motion-sensing system mounted on the lower back, a vibrotactile display worn around the torso, and a computer controller.(cont.) It can serve as a permanent or temporary replacement of motion cues, a tool for vestibular rehabilitation, or an additional sensory channel for military troops, pilots, and astronauts. This research demonstrates that well-compensated vestibulopathic patients can be differentiated from young and age-matched controls during over ground locomotion based on step width variability. Prior to this research, unilateral and bilateral vestibulopathic patients donning the vibrotactile balance prosthesis have demonstrated increased postural stability during single-axis support surface perturbations using single-axis sway information. This work shows that multi-directional vibrotactile tilt feedback reduces postural sway during multi-directional support surface perturbations, and has both short- and long-term effects on increasing postural stability. Finally, this research demonstrates for the first time that medial-lateral (M/L) tilt feedback can be used by balance-deficient subjects to reduce factors associated with fall risk (M/L tilt and M/L step width variability) during various locomotor tasks.by Kathleen H. Sienko.Ph.D

The effects of actuator selection on non-volitional postural responses to torso-based vibrotactile stimulation

Abstract Background Torso-based vibrotactile feedback may significantly reduce postural sway in balance-compromised adults during quiet standing or in response to perturbations. However, natural non-volitional postural responses to vibrotactile stimulation applied to the torso remain unknown. Methods The primary goal of this study was to determine, for two types of actuators (tactors) and in the absence of instruction, whether vibrotactile stimulation induces a directional postural shift as a function of stimulation location. Eleven healthy young adults (20 – 29 years old) were asked to maintain an upright erect posture with feet hip-width apart and eyes closed. Two types of tactors, Tactaid and C2, which differ in design and stimulation strength, were placed on the skin over the right and left external oblique, internal oblique, and erector spinae muscles in a horizontal plane corresponding approximately to the L4/L5 level. Each tactor of the same type was activated twice randomly for each individual location and twice simultaneously for all locations at a frequency of 250 Hz for a period of 5 s. Results Vibration applied over the internal oblique and erector spinae muscle locations induced a postural shift in the direction of the stimulation regardless of the tactor type. For the aforementioned four locations, the root-mean-square (RMS) and power spectral density (PSD) of the body sway in both the A/P and M/L directions were also significantly greater during the vibration than before or after, and were greater for the C2 tactors than for the Tactaid tactors. However, simultaneous activation of all tactors or those over the external oblique muscle locations did not produce significant postural responses regardless of the tactor type. Conclusion The results suggest that the use of a torso-based vibrotactile sensory augmentation display should carefully consider the tactor type as well as the instruction of corrective movements. Attractive instructional cues (“move in the direction of the vibration”) are compatible with the observed non-volitional response to stimulation and may facilitate postural adjustments during vibrotactile biofeedback balance applications.http://deepblue.lib.umich.edu/bitstream/2027.42/112652/1/12984_2012_Article_451.pd

Cell phone based balance trainer

<p>Abstract</p> <p>Background</p> <p>In their current laboratory-based form, existing vibrotactile sensory augmentation technologies that provide cues of body motion are impractical for home-based rehabilitation use due to their size, weight, complexity, calibration procedures, cost, and fragility.</p> <p>Methods</p> <p>We have designed and developed a cell phone based vibrotactile feedback system for potential use in balance rehabilitation training in clinical and home environments. It comprises an iPhone with an embedded tri-axial linear accelerometer, custom software to estimate body tilt, a "tactor bud" accessory that plugs into the headphone jack to provide vibrotactile cues of body tilt, and a battery. Five young healthy subjects (24 ± 2.8 yrs, 3 females and 2 males) and four subjects with vestibular deficits (42.25 ± 13.5 yrs, 2 females and 2 males) participated in a proof-of-concept study to evaluate the effectiveness of the system. Healthy subjects used the system with eyes closed during Romberg, semi-tandem Romberg, and tandem Romberg stances. Subjects with vestibular deficits used the system with both eyes-open and eyes-closed conditions during semi-tandem Romberg stance. Vibrotactile feedback was provided when the subject exceeded either an anterior-posterior (A/P) or a medial-lateral (M/L) body tilt threshold. Subjects were instructed to move away from the vibration.</p> <p>Results</p> <p>The system was capable of providing real-time vibrotactile cues that informed corrective postural responses. When feedback was available, both healthy subjects and those with vestibular deficits significantly reduced their A/P or M/L RMS sway (depending on the direction of feedback), had significantly smaller elliptical area fits to their sway trajectory, spent a significantly greater mean percentage time within the no feedback zone, and showed a significantly greater A/P or M/L mean power frequency.</p> <p>Conclusion</p> <p>The results suggest that the real-time feedback provided by this system can be used to reduce body sway. Its advantages over more complex laboratory-based and commercial balance training systems in terms of cost, size, weight, functionality, flexibility, and accessibility make it a good candidate for further home-based balance training evaluation.</p

Students’ perceptions of the value of stakeholder engagement during engineering design

BackgroundHuman‐centered design approaches promote and facilitate comprehensive understanding of stakeholders to inform design decisions. Successful engagement with stakeholders is critical to favorable design outcomes and requires skillful information gathering and synthesizing processes, which present unique challenges to student designers.Purpose/HypothesisOur study sought to answer the following research question: What factors influence design teams’ perceptions of the value of stakeholder engagement during design decision‐making?Design/MethodDuring a capstone design experience, we conducted four semistructured group interviews with seven capstone undergraduate student design teams and collected their design reports. We analyzed the data across teams to identify factors that influenced teams’ perceptions of the value of stakeholder engagement.ResultsTeams perceived stakeholder specific interactions to be more useful when they prespecified a goal for the interaction, interacted with stakeholders who had specific subject matter expertise, or ceded control of the decision‐making process to stakeholders. Students perceived interactions to be less useful when information gathered varied across stakeholders or when information was not directly applicable to the design decision at hand.ConclusionsThe factors this study identified that influenced students’ perceptions of the usefulness of stakeholder interactions elucidate specific challenges students encounter when engaging with stakeholders. Students could benefit from pedagogical structures that assist them throughout design‐related engagement with stakeholders and when applying the information gathered through engagements with stakeholders to design decision‐making.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163394/2/jee20356.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163394/1/jee20356_am.pd

Development of culturally appropriate pictorial cards to facilitate maternal health histories in rural Ghana

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135249/1/ijgo244.pd

The effects of attractive vs. repulsive instructional cuing on balance performance

Abstract Background Torso-based vibrotactile feedback has been shown to improve postural performance during quiet and perturbed stance in healthy young and older adults and individuals with balance impairments. These systems typically include tactors distributed around the torso that are activated when body motion exceeds a predefined threshold. Users are instructed to “move away from the vibration”. However, recent studies have shown that in the absence of instructions, vibrotactile stimulation induces small (~1°) non-volitional responses in the direction of its application location. It was hypothesized that an attractive cuing strategy (i.e., “move toward the vibration”) could improve postural performance by leveraging this natural tendency. Findings Eight healthy older adults participated in two non-consecutive days of computerized dynamic posturography testing while wearing a vibrotactile feedback system comprised of an inertial measurement unit and four tactors that were activated in pairs when body motion exceeded 1° anteriorly or posteriorly. A crossover design was used. On each day participants performed 24 repetitions of Sensory Organization Test condition 5 (SOT5), three repetitions each of SOT 1–6, three repetitions of the Motor Control Test, and five repetitions of the Adaptation Test. Performance metrics included A/P RMS, Time-in-zone and 95 % CI Ellipse. Performance improved with both cuing strategies but participants performed better when using repulsive cues. However, the rate of improvement was greater for attractive versus repulsive cuing. Conclusions The results suggest that when the cutaneous signal is interpreted as an alarm, cognition overrides sensory information. Furthermore, although repulsive cues resulted in better performance, attractive cues may be as good, if not better, than repulsive cues following extended training.http://deepblue.lib.umich.edu/bitstream/2027.42/134532/1/12984_2016_Article_131.pd

Obstetrics‐based clinical immersion of a multinational team of biomedical engineering students in Ghana

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135577/1/ijgo218.pd