Background: The emergence of smartphones and wearable sensor technologies enables easy and unobtrusive monitoring of physiological and psychological data related to an individual’s resilience. Heart rate variability (HRV) is a promising biomarker for resilience based on between-subject population studies, but observational studies that apply a within-subject design and use wearable sensors in order to observe HRV in a naturalistic real-life context are needed. Objective: This study aims to explore whether resting HRV and total sleep time (TST) are indicative and predictive of the within-day accumulation of the negative consequences of stress and mental exhaustion. The tested hypotheses are that demands are positively associated with stress and resting HRV buffers against this association, stress is positively associated with mental exhaustion and resting HRV buffers against this association, stress negatively impacts subsequent-night TST, and previous-evening mental exhaustion negatively impacts resting HRV, while previous-night TST buffers against this association. Methods: In total, 26 interns used consumer-available wearables (Fitbit Charge 2 and Polar H7), a consumer-available smartphone app (Elite HRV), and an ecological momentary assessment smartphone app to collect resilience-related data on resting HRV, TST, and perceived demands, stress, and mental exhaustion on a daily basis for 15 weeks. Results: Multiple linear regression analysis of within-subject standardized data collected on 2379 unique person-days showed that having a high resting HRV buffered against the positive association between demands and stress (hypothesis 1) and between stress and mental exhaustion (hypothesis 2). Stress did not affect TST (hypothesis 3). Finally, mental exhaustion negatively predicted resting HRV in the subsequent morning but TST did not buffer against this (hypothesis 4). Conclusions: To our knowledge, this study provides first evidence that having a low within-subject resting HRV may be both indicative and predictive of the short-term accumulation of the negative effects of stress and mental exhaustion, potentially forming a negative feedback loop. If these findings can be replicated and expanded upon in future studies, they may contribute to the development of automated resilience interventions that monitor daily resting HRV and aim to provide users with an early warning signal when a negative feedback loop forms, to prevent the negative impact of stress on long-term health outcomes.
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Background: The Strengths and Difficulties Questionnaire (SDQ) is widely used to screen for psychosocial problems among adolescents. As the severity of such problems is known to be related to age and gender, screening could be improved by interpreting SDQ scale scores with age-specific and perhaps gender-specific norms. Up to now, such norms are lacking. The aim of the current study is to present gender-specific and joint normative data per year of age for the Dutch self-reported and parent-reported SDQ versions for use among 12- to 17-year-old adolescents. Methods: The norm groups for the self-reported and parent-reported SDQ versions consisted of 993 adolescents and 736 parents, respectively, from the general Dutch population. Per SDQ version, both gender-specific norms and joint norms (percentiles and cutoffs) per year of age were calculated through regression-based norming (Rigby in J Roy Stat Soc Ser C 54:507, 2005). Additionally, these norms were compared to the widely used British norms that are neither age-specific nor gender-specific. Results: By design, gender-specific ‘abnormal’ cutoffs (i.e., cutoffs aimed at identifying max. 10% of the most extremely scoring males and max. 10% of the most extremely scoring females) resulted in about equal percentages of ‘abnormal’ scoring male and female adolescents per SDQ scale. In contrast, joint ‘abnormal’ cutoffs (i.e., cutoffs aimed at identifying max. 10% of the most extremely scoring adolescents) resulted in relatively more male (7.6 to 13.6%, depending on age) than female (3.3 to 8.9%, depending on age) adolescents as scoring ‘abnormal’ on scales measuring externalizing behavior (self-reported and parent-reported SDQ versions), and relatively more female (3.9 to 14.3%, depending on age) than male (1.8 to 6.9%, depending on age) adolescents as scoring ‘abnormal’ on scales measuring internalizing behavior (self-reported SDQ version). In both types of norms, minor age effects were present. Among Dutch adolescents, the British norms yielded detection rates much lower than the expected 10%. Conclusions: Our findings indicate that detection rates depend on the reference group that is used (British or Dutch general adolescent population; specific gender group or not). The normative data in this paper facilitate the comparison of an adolescent’s scores to different reference groups, and allow for cross-country/cultural comparisons of adolescents’ psychosocial behavior.
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Background: Recent technological developments such as wearable sensors and tablets with a mobile internet connection hold promise for providing electronic health home-based programs with remote coaching for patients following total hip arthroplasty. It can be hypothesized that such a home-based rehabilitation program can offer an effective alternative to usual care.Objective: The aim of this study was to determine the effectiveness of a home-based rehabilitation program driven by a tablet app and remote coaching for patients following total hip arthroplasty.Methods: Existing data of two studies were combined, in which patients of a single-arm intervention study were matched with historical controls of an observational study. Patients aged 18-65 years who had undergone total hip arthroplasty as a treatment for primary or secondary osteoarthritis were included. The intervention consisted of a 12-week home-based rehabilitation program with video instructions on a tablet and remote coaching (intervention group). Patients were asked to do strengthening and walking exercises at least 5 days a week. Data of the intervention group were compared with those of patients who received usual care (control group). Effectiveness was measured at four moments (preoperatively, and 4 weeks, 12 weeks, and 6 months postoperatively) by means of functional tests (Timed Up & Go test and the Five Times Sit-to Stand Test) and self-reported questionnaires (Hip disability and Osteoarthritis Outcome Score [HOOS] and Short Form 36 [SF-36]). Each patient of the intervention group was matched with two patients of the control group. Patient characteristics were summarized with descriptive statistics. The 1:2 matching situation was analyzed with a conditional logistic regression. Effect sizes were calculated by Cohen d.Results: Overall, 15 patients of the intervention group were included in this study, and 15 and 12 subjects from the control group were matched to the intervention group, respectively. The intervention group performed functional tests significantly faster at 12 weeks and 6 months postoperatively. The intervention group also scored significantly higher on the subscales "function in sport and recreational activities" and "hip-related quality of life" of HOOS, and on the subscale "physical role limitations" of SF-36 at 12 weeks and 6 months postoperatively. Large effect sizes were found on functional tests at 12 weeks and at 6 months (Cohen d=0.5-1.2), endorsed by effect sizes on the self-reported outcomes.Conclusions: Our results clearly demonstrate larger effects in the intervention group compared to the historical controls. These results imply that a home-based rehabilitation program delivered by means of internet technology after total hip arthroplasty can be more effective than usual care.Keywords: home-based rehabilitation program; internet; osteoarthritis; physiotherapy; rehabilitation; remote coaching; tablet app; total hip arthroplasty; total hip replacement; usual care.
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