Assessing the implementation of user-centred design standards on assistive technology for persons with visual impairments: a systematic review

Despite scientific and technological advances in the field of assistive technology (AT) for people with visual impairment (VI), technological designs are frequently based on a poor understanding of the physical and social context of use, resulting in devices that are less than optimal for their intended beneficiaries. To resolve this situation, user-centred approaches in the development process of AT have been widely adopted in recent years. However, there is a lack of systematization on the application of this approach. This systematic review registered in PROSPERO (CRD42022307466), assesses the application of the ISO 9241-210 human-centred design principles in allegedly "user-centred designed" AT developments for persons with VI (see Supplementary PROSPERO Protocol). The results point to a wide variation of the depth of understanding of user needs, a poor characterization of the application of the User Centred Design (UCD) approach in the initial design phases or in the early prototyping, and a vague description of user feedback and device iteration. Among the principles set out in ISO 9241-210, the application of 5.6: "the design team includes multidisciplinary skills and perspectives" is the one for which the least evidence is found. The results show there is not enough evidence to fully assess the impact of UCD in (1) promoting innovation regarding AT products and practices, and (2) Judging if AT produced following such standards is leading to better user access, wellbeing outcomes and satisfaction. To address this gap it is necessary to, first, generate better implementation of UCD in AT development and second, to strengthen evidence regarding the implementation and outcomes of using UCD for AT. To better engage with the realities of persons with VI, we propose capacity building across development teams regarding UCD, its principles and components; better planning for UCD implementation; and cross-fertilization across engineering disciplines and social and clinical science.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=307466 PROSPERO (CRD42022307466).

Assessment of water, sanitation, and hygiene services in district health care facilities in rural area of Mekong Delta, Vietnam

Access to sufficient water, sanitation, and hygiene (WASH) services is a crucial requirement for patients during therapy and general well-being in the hospital. However, in low- and middle-income countries, these services are often inadequate, resulting in increased morbidity and mortality of patients. This study aimed at assessing the current situation of WASH services in six District Health Care Facilities (DHCFs) in rural areas of the Mekong Delta provinces, Vietnam. The results showed that these services were available with inappropriate quality, which did not compromise the stakeholders' needs. The revealed WASH infrastructures have raised concerns about the prolonged hospital stays for patients and push nosocomial infections to a high level. The safety of the water supply was doubted as the high E. coli (> 60%) and total coliform incidence (86%) was observed with very low residual chlorine concentration (< 0.1 mg/L) in water quality assessment. Moreover, water supply contained a high concentration of iron (up to 15.55 mg/L) in groundwater in one DHCF. Technical assessment tool analysis proved that the improper management and lack of knowledge by human resources were the primary roots of the observed status WASH services. Improvement of the perceptions of WASH should be done for the hospital staff with collaboration and support from the government to prevent incidents in the future.

The status of refrigeration solutions for last mile vaccine delivery in low-income settings

Recommendations for storage of most vaccines imply a continuous exposure to a temperature range between 0 °C and 10 °C, from the production to the administration to beneficiaries. According to the World Health Organization, more than 50% of vaccines are wasted around the world. Discontinuities of the cold chain in low-income settings where electricity is scarce contributes to this wastage. Recently, several advances have been made in cooling technologies to store and transport vaccines. This paper presents an overview of refrigeration technologies based on scientific publications, industry white papers and other grey literature. With a focus on vaccine transport, we briefly describe each refrigeration method, its best performing available devices as well as the outstanding research challenges in order to further improve its performance.

A functional approach towards the design, development, and test of an affordable dynamic prosthetic foot

Humanitarian actors involved in physical rehabilitation, such as the International Committee of the Red Cross (ICRC), usually provide their beneficiaries with lower-limb prostheses comprising Solid Ankle Cushion Heel (SACH) feet as these are considered appropriate (price, durability, low profile to fit a majority of patients, appearance) and reliable for all ambulation levels. However, individuals in low-resource settings having higher ambulation abilities would greatly benefit from dynamic prosthetic feet with improved biomechanics and energy storage and release. Some attempts tried to address this increasing need (e.g. Niagara Foot) but most products proposed by large manufacturers often remain unaffordable and unsuitable to the context of low-resource settings. The design requirements and a price target were defined in partnership with the ICRC according to their initial assessment and used as a starting point for the development process and related technological choices. Numerical simulation and modeling were used to work on the design and to determine the required materials properties (mechanical, chemical, wear), and a cost modeling tool was used to select suitable materials and relevant processing routes (price vs. performance). A prosthetic foot comprising an internal keel made of composite materials, a filling foam, and a cosmetic shell with a foot shape was developed. Manufacturing processes meeting the cost criteria were identified and prototype feet were produced accordingly. These were successfully tested using a compression testing system before gait analyses were performed in the laboratory with non-amputees wearing testing boots. After validation in laboratory conditions, the prototype foot was tested in the field (Vietnam) with 11 trans-tibial unilateral amputees, who showed an increased mobility compared with the SACH foot. The collaboration of different research fields led to the development of a prosthetic foot which met the technical requirements determined by the ICRC’s specific needs in its field of operation. The materials and selected production processes led to a manufacturing cost of less than 100 USD per part.

Ending Neonatal Deaths From Hypothermia in Sub-Saharan Africa: Call for Essential Technologies Tailored to the Context

Neonatal death represents a major burden in Sub-Saharan Africa (SSA), where the main conditions triggering mortality, such as prematurity, labor complications, infections, and respiratory distress syndrome, are frequently worsened by hypothermia, which dramatically scales up the risk of death. In SSA, the lack of awareness on the procedures to prevent hypothermia and the shortage of essential infant devices to treat it are hampering the reduction of neonatal deaths associated to hypothermia. Here, we offer a snapshot on the current available medical solutions to prevent and treat hypothermia in SSA, with a focus on Kenya. We aim to provide a picture that underlines the essential need for infant incubators in SSA. Specifically, given the inappropriateness of the incubators currently on the market, we point out the need for reinterpretation of research in the field, calling for technology-based solutions tailored to the SSA context, the need, and the end-user.

X-ray imaging detector for radiological applications adapted to the context and requirements of low- and middle-income countries

This paper describes the development of a novel medical x-ray imaging system adapted to the needs and constraints of low- and middle-income countries. The developed system is based on an indirect conversion chain: a scintillator plate produces visible light when excited by the x rays, and then, a calibrated multi-camera architecture converts the visible light from the scintillator into a set of digital images. The partial images are then unwarped, enhanced, and stitched through parallel field programmable gate array processing units and specialized software. All the detector components were carefully selected focusing on optimizing the system's image quality, robustness, cost-effectiveness, and capability to work in harsh tropical environments. With this aim, different customized and commercial components were characterized. The resulting detector can generate high quality medical diagnostic images with detective quantum efficiency levels up to 60% (@2.34 μGy), even under harsh environments, i.e., 60 °C and 98% humidity.

Study protocol for a two-site clinical trial to validate a smartphone-based artificial intelligence classifier identifying cervical precancer and cancer in HPV-positive women in Cameroon

INTRODUCTION

Cervical cancer remains a major public health challenge in low- and middle-income countries (LMICs) due to financial and logistical issues. WHO recommendation for cervical cancer screening in LMICs includes HPV testing as primary screening followed by visual inspection with acetic acid (VIA) and treatment. However, VIA is a subjective procedure dependent on the healthcare provider's experience. Its accuracy can be improved by computer-aided detection techniques. Our aim is to assess the performance of a smartphone-based Automated VIA Classifier (AVC) relying on Artificial Intelligence to discriminate precancerous and cancerous lesions from normal cervical tissue.

METHODS

The AVC study will be nested in an ongoing cervical cancer screening program called "3T-study" (for Test, Triage and Treat), including HPV self-sampling followed by VIA triage and treatment if needed. After application of acetic acid on the cervix, precancerous and cancerous cells whiten more rapidly than non-cancerous ones and their whiteness persists stronger overtime. The AVC relies on this key feature to determine whether the cervix is suspect for precancer or cancer. In order to train and validate the AVC, 6000 women aged 30 to 49 years meeting the inclusion criteria will be recruited on a voluntary basis, with an estimated 100 CIN2+, calculated using a confidence level of 95% and an estimated sensitivity of 90% +/-7% precision on either side. Diagnostic test performance of AVC test and two current standard tests (VIA and cytology) used routinely for triage will be evaluated and compared. Histopathological examination will serve as reference standard. Participants' and providers' acceptability of the technology will also be assessed. The study protocol was registered under ClinicalTrials.gov (number NCT04859530).

EXPECTED RESULTS

The study will determine whether AVC test can be an effective method for cervical cancer screening in LMICs.

Teaching an engine-driven preparation technique to undergraduates: initial observations

AIM

This paper describes the initial experiences following the introduction of a rotary engine-driven preparation technique into the undergraduate endodontic programme at the Zurich University Dental Centre.

METHODS

Forty third-year students practised the ProFile.04 (PF.04) technique between January and July 2001 in a preclinical course. Between November 2001 and February 2002, 20 of these students (Group A) root-treated 51 teeth in their clinical course using either PF.04, the balanced force technique (BFT) or a combination of both. The second group of 20 students (Group B) similarly treated another 36 randomly selected teeth between April and July 2002. Types of teeth treated by the students and the canal preparation techniques were recorded. The students also completed a short questionnaire, evaluating their opinions of the new course.

RESULTS

Of the 87 teeth endodontically treated during the clinical course, 34, 14 and 39 were shaped using PF.04 alone, a combination of PF.04 and BFT and BFT alone, respectively. No rotary instruments were fractured during the 1-year clinical course, although some instruments were fractured during the preclinical laboratory course. Overall, the students rated the rotary technique as positive.

CONCLUSION

A rotary technique was successfully introduced into an undergraduate endodontic programme (this will be continued in the foreseeable future). However, the continuity between the preclinical and the clinical courses was poor as a result of the constraints of the general teaching programme.

ProTaper rotary root canal preparation: effects of canal anatomy on final shape analysed by micro CT

AIM

To evaluate the relative performance of ProTaper nickel-titanium (Ni-Ti) instruments shaping root canals of varying preoperative canal geometry.

METHODOLOGY

Extracted human maxillary molars were scanned, before and after shaping with ProTaper, employing micro computed tomography (muCT) at a resolution of 36 mum. Canals were three-dimensionally reconstructed and evaluated for volume, surface area, 'thickness' (diameter), canal transportation and prepared surface. Based on median canal volume, canals were divided into 'wide' and 'constricted' groups. Comparisons were made between mesiobuccal (mb), distobuccal (db) and palatal (p), as well as 'wide' and 'constricted' canals, using repeated-measures anova and Scheffé posthoc tests.

RESULTS

Volume and surface area increased significantly and similarly in mb, db and p canals, and gross preparation errors were found infrequently. Root canal diameters, 5-mm coronal to the apex, increased from 0.38 to 0.65 mm, 0.42 to 0.66 mm and 0.57 to 0.79 mm for mb, db and p canals, respectively. Apical canal transportation ranged from 0.02 to 0.40 mm and was independent of canal type; 'wide' canals had a significantly higher (P < 0.05) proportion of unprepared surfaces than 'constricted' canals.

CONCLUSIONS

Canals in maxillary molars were prepared in vitro using ProTaper instruments without major procedural errors. These instruments may be more effective in shaping narrow canals than wider, immature ones.

ProTaper rotary root canal preparation: assessment of torque and force in relation to canal anatomy

AIM

To investigate physical parameters for ProTaper nickel-titanium (NiTi) rotary instruments whilst preparing curved canals in maxillary molars in vitro.

METHODOLOGY

A novel torque-testing platform was used to prepare root canals in 15 extracted human maxillary molars with ProTaper rotary instruments. Peak torque and force was registered along with numbers of rotations required to shape the canals. Canals were divided into 'wide' and 'constricted' groups depending on canal volumes assessed by micro computed tomography. Mean scores for each instrument type were calculated and statistically compared using anova and Scheffé posthoc tests.

RESULTS

Mean torque varied between 0.8 +/- 0.5 and 2.2 +/- 1.4 N cm whilst mean force ranged from 4.6 +/- 2.6 to 6.2 +/- 2.7 N. Mean numbers of rotations totalled up to 21. All three variables registered were significantly correlated to preoperative canal volumes (P < 0.001) and differed significantly between 'wide' and 'constricted' canals (P < 0.001).

CONCLUSIONS

Whilst high forces were used in some cases, no ProTaper instrument fractured when a patent glide path was present. There were significant positive correlations between canal geometry and physical parameters during shaping.

Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography

AIM

The aim of this study was to compare the effects of four preparation techniques on canal volume and surface area using three-dimensionally reconstructed root canals in extracted human maxillary molars. In addition, micro CT data was used to describe morphometric parameters related to the four preparation techniques.

METHODOLOGY

A micro computed tomography scanner was used to analyse root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using Ni-Ti - K-Files, Lightspeed instruments, ProFile.04 and GT rotary instruments. Differences in dentine volume removed, canal straightening, the proportion of unchanged area and canal transportation were calculated using specially developed software.

RESULTS

Instrumentation of canals increased volume and surface area. Prepared canals were significantly more rounded, had greater diameters and were straighter than unprepared canals. However, all instrumentation techniques left 35% or more of the canals' surface area unchanged. Whilst there were significant differences between the three canal types investigated, very few differences were found with respect to instrument types.

CONCLUSIONS

Within the limitations of the micro CT system, there were few differences between the four canal instrumentation techniques used. By contrast, a strong impact of variations of canal anatomy was demonstrated. Further studies with 3D-techniques are required to fully understand the biomechanical aspects of root canal preparation.

Temperature-related reversible birefringence changes in rat tail tendon

By use of a highly sensitive method for measuring slight variations in birefringence it is shown here that a strong reversible correlation exists between rat tail tendon birefringence and temperature. This phenomenon is totally different from the loss of birefringence that results from a denaturation process. Below the threshold temperature leading to denaturation, an increase in temperature is systematically accompanied by a reversible increase in birefringence (0.25% degrees C(-1)). This phenomenon is observed at very fast heating rates (250,000 degrees C s(-1)), such as those induced by pulsed infrared lasers, and confirmed by experiments conducted with slow homogeneous heating of the sample medium (0.1 degrees C s(-1)). The good correlation between birefringence and temperature observed during the fast heating suggests that there are only small modifications of the tissue structure at the fibril level.

Polarization discrimination of coherently propagating light in turbid media

We describe the use of degree of polarization to discriminate unscattered and weakly scattered light from multiply scattered light in an optically turbid material. We use spatially resolved measurements of the degree of polarization to compare how well linearly and circularly polarized light survives in a sample. Experiments were performed on common tissue phantoms consisting of polystyrene and Intralipid microsphere suspensions and on adipose and arterial tissue. The results indicate that polarization is maintained even after unpolarized irradiance through each sample has been extinguished by several orders of magnitude. The results also show that polarized light propagation in common tissue phantoms is distinctly different from polarized light propagation in the two tissues investigated. Further, these experiments illustrate when polarization is an effective discrimination criterion and when it is not. The potential of a polarization-based discrimination scheme to image through the biological and nonbiological samples investigated here is also discussed.

[High-caloric nutrition in chronic obstructive lung disease]

A body weight lower than 90% of the optional value has an unfavorable influence on the prognosis of chronic obstructive pulmonary disease (COPD). Short term studies of up to three months duration have shown improved function of respiratory muscle exercise tolerance and immunologic parameters by an increased caloric intake of 45 kcal/kg body weight. In a randomized trial of twelve months 14 of 30 patients with an average FEV1 of 0.8 l were instructed to take a high calorie diet. For simplicity a part of the calories were administered as Fresubin, a fluid nutrient formula. Although a weight gain of 7 kg (p = 0.003) was obtained the difference to the control group was statistically not significant (p = 0.08). The same was true for skin fold thickness (12.4 vs 5.7 mm), change of ventilatory parameters and the 6 minute walking distance (-33 vs -86 m). Subjective improvement was, however, impressive in all patients with dietary intervention, explainable probably by increased attention. Dietary counselling for increased intake of calories, vitamins and also calcium is thus very important in the treatment of patients with COPD.