Non-invasive pulse arrival time as a surrogate for oscillometric systolic blood pressure changes during non-pharmacological intervention.

Background.Non-invasive continuous blood pressure (BP) monitoring is of longstanding interest in various cardiovascular scenarios. In this context, pulse arrival time (PAT), i.e., a surrogate parameter for systolic BP (change), became very popular recently, especially in the context of cuffless BP measurement and dedicated lifestyle interventions. Nevertheless, there is also understandable doubt on its reliability in uncontrolled and mobile settings.Objective.The aim of this work is therefore the investigation whether PAT follows oscillometric systolic BP readings during moderate interventions by physical or mental activity using a medical grade handheld device for non-invasive PAT assessment.Approach.A study was conducted featuring an experimental group performing a physical and a mental task, and a control group. Oscillometric BP and PAT were assessed at baseline and after each intervention. Interventions were selected randomly but then performed sequentially in a counterbalanced order. Multivariate analyses of variance were used to test within-subject and between-subject effects for the dependent variables, followed by univariate analyses for post-hoc testing. Furthermore, correlation analysis was performed to assess the association of intervention effects between BP and PAT.Mainresults.The study included 51 subjects (31 females). Multivariate analysis of variances showed that effects in BP, heart rate, PAT and pulse wave parameters were consistent and significantly different between experimental and control groups. After physical activity, heart rate and systolic BP increased significantly whereas PAT decreased significantly. Mental activity leads to a decrease in systolic BP at stable heart rate. Pulse wave parameters follow accordingly by an increase of PAT and mainly unchanged pulse wave analysis features due to constant heart rate. Finally, also the control group behaviour was accurately registered by the PAT method compared to oscillometric cuff. Correlation analyses revealed significant negative associations between changes of systolic BP and changes of PAT from baseline to the physical task (-0.33 [-0.63, 0.01],p< 0.048), and from physical to mental task (-0.51 [-0.77, -0.14],p= 0.001), but not for baseline to mental task (-0.12 [-0,43,0,20],p= 0.50) in the experimental group.Significance.PAT and the used digital, handheld device proved to register changes in BP and heart rate reliably compared to oscillometric measurements during intervention. Therefore, it might add benefit to future mobile health solutions to support BP management by tracking relative, not absolute, BP changes during non-pharmacological interventions.

Usability testing of the first prototype of the Memento system: a technological device to promote an independent living in people with dementia.

PURPOSE: Assistive technologies have the potential for supporting people with memory complaints in their daily life. User-centered interaction design research helps developers to create systems that are suitable for users. The aim of this work is to describe the methodology and the results of the usability test for the first Memento prototype involving users. MATERIALS AND METHODS: In each country, 5 subjects with different levels of cognitive reserve and technical proficiency were enrolled in Italy, Austria and Spain, respectively (15 subjects; 6 M; 9 F, age 72.8 ± 10.8 years, MMSE score 25.6 ± 1.6). Observation methods, performance metrics and the System Usability Scale were used to collect data. RESULTS: The results are presented in terms of design, technical problems, target-group-related challenges and usability perception from the participant perspective. Suggestions for improvement were pointed out by the users. Considering the usability scores interpretation, the first prototype was classified as "OK" and "Good" by users. CONCLUSIONS: The results of the Lab Trials provide important information on usability and the users' needs in order to improve the Memento prototype and to create a final system to be evaluated during the Field Trials phase of the project.Implication for rehabilitationThe MEMENTO project mission is to improve the quality of life of people in the early and middle stages of dementia, by supporting the management of daily activities that are usually affected by the loss of memory and cognition. The Lab Trial phase is essential to have feedback on the usability of the Memento prototype to allow a better understanding of users' needs and expectations.

User experience and acceptance of a device assisting persons with dementia in daily life: a multicenter field study.

BACKGROUND: Assistive technologies have the potential to facilitate everyday life of people with dementia and their families. Close collaboration with affected people and interdisciplinary research are essential to understand and address the needs of prospective users. In this study, we present the results of the evaluation of such an assistive system prototype. AIMS: Challenges from the patient and caregiver side, technical and design problems and acceptance and usability with regard to our special target group were evaluated. METHODS: MEMENTO, a system of two e-ink tablets and a smartwatch, was tested in the domestic environment of dementia patients. Thirty participants from Italy, Spain and Austria took part in a 3-month field trial and compared the MEMENTO system to traditional strategies in everyday life. Quantitative and qualitative data were collected and frequency of use of the system was monitored. RESULTS: There were no significant changes in quantitative measurements, such as activities of daily living and caregiver burden over the duration of the 3-month field trial. More frequent usage was significantly correlated with positive attitude towards technology (r = 0.723, p < 0.05), but not with age. The design of the system was positively emphasized, reducing fear of the technology on the one hand and stigmatization on the other. CONCLUSION: We show that a positive attitude towards technology is the essential variable for successful implementation of such systems, regardless of age. Participants showed great interest in digital solutions and agreed that technological systems will help in maintaining independency of persons with cognitive dysfunction in the future.