Disrupted Rest-Activity Rhythms and Cerebral Small Vessel Disease Pathology in Older Adults.

BACKGROUND AND PURPOSE: The pathogenesis of cerebral small vessel disease remains incompletely understood. The relationship between circadian rhythm disturbances and histopathologic measures of cerebral small vessel disease has not been studied. We hypothesized that disrupted circadian rest-activity rhythms would be associated with a higher burden of cerebral small vessel disease pathology. METHODS: We studied 561 community-dwelling older adults (mean age at death, 91.2, 27.4% male) from the Rush Memory and Aging Project. We used actigraphy to quantify several measures of 24-hour rest-activity rhythmicity, including interdaily stability, intradaily variability, and amplitude, and used ordinal logistic regression models to relate these measures to the severity of cerebral arteriolosclerosis, atherosclerosis, macroinfarcts, and microinfarcts, assessed at autopsy. RESULTS: Lower interdaily stability was associated with a higher burden of arteriolosclerosis, higher intradaily variability was associated with a higher burden of atherosclerosis and subcortical infarcts, and lower amplitude was associated with a higher burden of arteriosclerosis, atherosclerosis and subcortical macroinfarcts. Moreover, the associations between interdaily stability and arteriolosclerosis and intradaily variability and subcortical infarcts were independent of cardiovascular risk factors, sleep fragmentation, and medical comorbidities. CONCLUSIONS: Disrupted rest-activity rhythms are associated with a greater burden of cerebral small vessel disease in older adults.

Practice parameters for the use of actigraphy in the military operational context: the Walter Reed Army Institute of Research Operational Research Kit-Actigraphy (WORK-A).

BACKGROUND: The Walter Reed Army Institute of Research (WRAIR) Operational Research Kit-Actigraphy (WORK-A) is a set of unique practice parameters and actigraphy-derived measures for the analysis of operational military sleep patterns. The WORK-A draws on best practices from the literature and comprises 15 additional descriptive variables. Here, we demonstrate the WORK-A with a sample of United States Army Reserve Officers' Training Corps (ROTC) cadets (n = 286) during a month-long capstone pre-commissioning training exercise. METHODS: The sleep of ROTC cadets (n = 286) was measured by Philips Actiwatch devices during the 31-day training exercise. The preliminary effectiveness of the WORK-A was tested by comparing differences in sleep measures collected by Actiwatches as calculated by Philips Actiware software against WORK-A-determined sleep measures and self-report sleep collected from a subset of ROTC cadets (n = 140). RESULTS: Actiware sleep summary statistics were significantly different from WORK-A measures and self-report sleep (all P ≤ 0.001). Bedtimes and waketimes as determined by WORK-A major sleep intervals showed the best agreement with self-report bedtime (22:21 ± 1:30 vs. 22:13 ± 0:40, P = 0.21) and waketime (04:30 ± 2:17 vs. 04:31 ± 0:47, P = 0.68). Though still significantly different, the discrepancy was smaller between the WORK-A measure of time in bed (TIB) for major sleep intervals (352 ± 29 min) and self-report nightly sleep duration (337 ± 57 min, P = 0.006) than that between the WORK-A major TIB and Actiware TIB (177 ± 42, P ≤ 0.001). CONCLUSIONS: Default actigraphy methods are not the most accurate methods for characterizing soldier sleep, but reliable methods for characterizing operational sleep patterns is a necessary first step in developing strategies to improve soldier readiness. The WORK-A addresses this knowledge gap by providing practice parameters and a robust variety of measures with which to profile sleep behavior in service members.

Association of Circadian Abnormalities in Older Adults With an Increased Risk of Developing Parkinson Disease.

Importance: Disruption in circadian activity rhythms is very common in older adults, particularly among those with neurodegenerative diseases, including Parkinson disease (PD). However, whether circadian disruption could be a prodrome for PD is unclear. Objective: To determine the association between rest-activity rhythm (RAR) and risk of incident PD and to explore whether this association is independent of nighttime sleep disturbances. Design, Setting, and Participants: The ancillary sleep study of the longitudinal cohort Osteoporotic Fractures in Men Study (MrOS) was conducted from December 1, 2003, to March 31, 2005. Of the 3135 community-dwelling men enrolled in the MrOS sleep study, 3049 had technically adequate RAR data; of these, 119 were excluded for having prevalent PD or missing incident data, leaving 2930 men without PD at baseline. Data were analyzed from February 1 through August 31, 2019. Exposures: Twenty four-hour RAR parameters (amplitude, mesor, robustness, and acrophase) generated by wrist actigraphy-extended cosinor analysis. Main Outcomes and Measures: Incident PD based on physician diagnosis. Multivariable logistic regression was used to determine the association between quartiles of RAR parameters and risk of incident PD. Results: Among the 2930 men included in the analysis (mean [SD] age, 76.3 [5.5] years), 78 (2.7%) developed PD during 11 years of follow-up. After accounting for all covariates, the risk of PD increased with decreasing circadian amplitude (strength of the rhythm) (odds ratio [OR] per 1-SD decrease, 1.77; 95% CI, 1.30-2.41), mesor (mean level of activity) (OR per 1-SD decrease, 1.64; 95% CI, 1.22-2.21), or robustness (how closely activity follows a cosine 24-hour pattern) (OR per 1-SD decrease, 1.54; 95% CI, 1.14-2.07) (P < .005 for trend). Those in the lowest quartile of amplitude, mesor, or robustness had approximately 3 times the risk of developing PD compared with those in the highest quartile of amplitude (OR, 3.11; 95% CI, 1.54-6.29), mesor (OR, 3.04; 95% CI, 1.54-6.01), and robustness (OR, 2.65; 95% CI, 1.24-5.66). The association remained after further adjustment for nighttime sleep disturbances and duration in the lowest compared with the highest quartile (OR for amplitude, 3.56 [95% CI, 1.68-7.56]; OR for mesor, 3.24 [95% CI, 1.52-6.92]; and OR for robustness, 3.34 [95% CI, 1.45-7.67]). These associations were somewhat attenuated, but the pattern remained similar after excluding PD cases developed within 2 years after baseline in the lowest compared with the highest quartile (OR for amplitude, 2.40 [95% CI, 1.15-5.00]; OR for mesor, 2.76 [95% CI, 1.35-5.67]; and OR for robustness, 2.33 [95% CI, 1.07-5.07]). Acrophase was not significantly associated with risk of PD. Conclusions and Relevance: In this cohort study, reduced circadian rhythmicity was associated with an increased risk of incident PD, suggesting it may represent an important prodromal feature for PD. Future studies are needed to determine whether circadian disruption could also be a risk factor for PD and whether strategies to improve circadian function affect the risk of PD.

Infant sleep moderates the effect of infant temperament on maternal depressive symptoms, maternal sensitivity, and family functioning.

Observed infant temperamental difficulty and infant sleep efficiency and sleep variability were examined as predictors of maternal depressive symptoms, maternal sensitivity, and family functioning. Eight observations at 8-months postpartum were used to assess infant temperament, and actigraphy was used to measure infant sleep for 1-week at the time of the 8-month assessment. Structured clinical interviews were used to assess maternal depressive symptoms between 5 and 12 months postpartum and at 15 months postpartum, and observational assessments were used to assess maternal sensitivity and family functioning at 15 months postpartum. Variability in infant sleep moderated the effect of infant temperament on maternal depressive symptoms, maternal sensitivity, and family functioning. Infant temperament was positively associated with maternal depressive symptoms when variability in infant sleep efficiency was high, but not when variability in infant sleep efficiency was low. Likewise, infant temperament was negatively associated with maternal sensitivity and family functioning when variability in infant sleep efficiency was high, but not when variability in infant sleep efficiency was low. Results underscore the importance of infant sleep for maternal and family health.

The day after: correlates of patient-reported outcomes with actigraphy-assessed sleep in cancer patients at home (inCASA project).

Subjective sleep assessment in cancer patients poorly correlates with actigraphy parameters that usually encompass multiple nights. We aimed to determine the objective actigraphy measures that best correlated with subjective sleep ratings on a night-by-night basis in cancer patients. Thirty-one cancer patients daily self-rated sleep disturbances using the single dedicated item of the MD Anderson Symptom Inventory (0-10 scale) with 18 other items, and continuously wore a wrist actigraph for 30 days. Objective sleep parameters were computed from the actigraphy nighttime series, and correlated with subjective sleep disturbances reported on the following day, using repeated measures correlations. Multilevel Poisson regression analysis was performed to identify the objective and subjective parameters that affected subjective sleep rating. Poor subjective sleep score was correlated with poor sleep efficiency (rrm = -0.13, p = 0.002) and large number of wake episodes (rrm = 0.12, p = 0.005) on the rated night. Multilevel analysis demonstrated that the expected sleep disturbance score was affected by the joint contribution of the wake episodes (exp(ß) = 1.01, 95% confidence interval = 1.00 to 1.02, p = 0.016), fatigue (exp(ß) = 1.35, 95% confidence interval = 1.15 to 1.55, p < 0.001) and drowsiness (exp(ß) = 1.70, 95% confidence interval = 1.19 to 2.62, p = 0.018), self-rated the following evening, and sleep disturbance experienced one night before (exp(ß) = 1.77, 95% confidence interval = 1.41 to 2.22, p < 0.001). The night-by-night approach within a multidimensional home tele-monitoring framework mainly identified the objective number of wake episodes computed from actigraphy records as the main determinant of the severity of sleep complaint in cancer patients on chemotherapy. This quantitative information remotely obtained in real time from cancer patients provides a novel framework for streamlining and evaluating interventions toward sleep improvement in cancer patients.

Practical aspects of actigraphy and approaches in clinical and research domains.

Actigraphy involves acquisition of data using a movement sensor worn continuously on the nondominant wrist, typically for a week or more. Computer-based algorithms estimate sleep episodes by analysis of continuous minutes of no to low movement, or spans of time when movement is relatively low compared with movements during presumed ambulatory wakefulness. Inherent advantages of actigraphy over polysomnography include its noninvasive nature, cost-effectiveness, lesser burden on patients/research participants, and ability to collect data over multiple days/nights, thereby allowing examination of sleep-wake patterning. Therefore, actigraphy is emerging as a common method to objectively assess sleep parameters providing estimates of sleep duration and continuity. Modes of actigraphy data collection, scoring algorithms, sleep quality/disturbance measures, validation studies, and clinical and research applications are discussed.

Developmental trends in sleep during adolescents' transition to young adulthood.

OBJECTIVE: Poor sleep poses negative health consequences for youth, yet few longitudinal actigraphy studies have examined basic developmental trends in sleep across adolescents' transition to young adulthood. In this longitudinal actigraphy study, stability of individual differences and trajectories of sleep during and after high school were examined. The degree to which sleep trajectories differed by college attendance status was also studied. METHODS: A total of 343 youth with Asian, Latino, and European American backgrounds completed eight days of wrist actigraphy at two-year intervals in Wave 1 (n = 295, Mage = 16.39), Wave 2 (n = 211 including 34 new participants to refresh the sample, Mage = 18.31), and Wave 3 (n = 144, Mage = 20.29). Sleep duration, efficiency, and latency were estimated for weekdays and weekends. Intra-individual variability in duration across nights was also obtained. RESULTS: Sleep parameters were correlated modestly between Wave 1 and Wave 2, but not correlated between Wave 1 and Wave 3, indicating modest shorter-term and little longer-term stability of individual differences. Multilevel growth models demonstrated declines in weekday sleep duration and efficiency across high school and post-high school years. Intra-individual variability in duration increased over the years. Latency trajectories changed more for non-college attendees compared with college attendees. CONCLUSIONS: Overall the findings suggest developmental trends of worsening sleep during adolescents' transition to young adulthood. Interventions to improve sleep may need to target specific issues faced by youth at that particular period in their lives.

Effect of pedometer-based walking interventions on long-term health outcomes: Prospective 4-year follow-up of two randomised controlled trials using routine primary care data.

BACKGROUND: Data are lacking from physical activity (PA) trials with long-term follow-up of both objectively measured PA levels and robust health outcomes. Two primary care 12-week pedometer-based walking interventions in adults and older adults (PACE-UP and PACE-Lift) found sustained objectively measured PA increases at 3 and 4 years, respectively. We aimed to evaluate trial intervention effects on long-term health outcomes relevant to walking interventions, using routine primary care data. METHODS AND FINDINGS: Randomisation was from October 2012 to November 2013 for PACE-UP participants from seven general (family) practices and October 2011 to October 2012 for PACE-Lift participants from three practices. We downloaded primary care data, masked to intervention or control status, for 1,001 PACE-UP participants aged 45-75 years, 36% (361) male, and 296 PACE-Lift participants, aged 60-75 years, 46% (138) male, who gave written informed consent, for 4-year periods following randomisation. The following new events were counted for all participants, including those with preexisting diseases (apart from diabetes, for which existing cases were excluded): nonfatal cardiovascular, total cardiovascular (including fatal), incident diabetes, depression, fractures, and falls. Intervention effects on time to first event post-randomisation were modelled using Cox regression for all outcomes, except for falls, which used negative binomial regression to allow for multiple events, adjusting for age, sex, and study. Absolute risk reductions (ARRs) and numbers needed to treat (NNTs) were estimated. Data were downloaded for 1,297 (98%) of 1,321 trial participants. Event rates were low (<20 per group) for outcomes, apart from fractures and falls. Cox hazard ratios for time to first event post-randomisation for interventions versus controls were nonfatal cardiovascular 0.24 (95% confidence interval [CI] 0.07-0.77, p = 0.02), total cardiovascular 0.34 (95% CI 0.12-0.91, p = 0.03), diabetes 0.75 (95% CI 0.42-1.36, p = 0.34), depression 0.98 (95% CI 0.46-2.07, p = 0.96), and fractures 0.56 (95% CI 0.35-0.90, p = 0.02). Negative binomial incident rate ratio for falls was 1.07 (95% CI 0.78-1.46, p = 0.67). ARR and NNT for cardiovascular events were nonfatal 1.7% (95% CI 0.5%-2.1%), NNT = 59 (95% CI 48-194); total 1.6% (95% CI 0.2%-2.2%), NNT = 61 (95% CI 46-472); and for fractures 3.6% (95% CI 0.8%-5.4%), NNT = 28 (95% CI 19-125). Main limitations were that event rates were low and only events recorded in primary care records were counted; however, any underrecording would not have differed by intervention status and so should not have led to bias. CONCLUSIONS: Routine primary care data used to assess long-term trial outcomes demonstrated significantly fewer new cardiovascular events and fractures in intervention participants at 4 years. No statistically significant differences between intervention and control groups were demonstrated for other events. Short-term primary care pedometer-based walking interventions can produce long-term health benefits and should be more widely used to help address the public health inactivity challenge. TRIAL REGISTRATIONS: PACE-UP isrctn.com ISRCTN98538934; PACE-Lift isrctn.com ISRCTN42122561.

Racial/ethnic disparities in women's sleep duration, continuity, and quality, and their statistical mediators: Study of Women's Health Across the Nation.

STUDY OBJECTIVES: To describe racial/ethnic differences in sleep duration, continuity, and perceived sleep quality in postmenopausal women and to identify statistical mediators of differences in sleep characteristics. METHODS: Recruited from the observational Study of Women's Health Across the Nation (SWAN), 1,203 (548 white, 303 black, 147 Chinese, 132 Japanese, and 73 Hispanic; mean age 65 years, 97% postmenopausal) women participated in a week-long actigraphy and daily diary study in 2013-2015. Actigraphic measures of sleep duration and wake after sleep onset (WASO), and diary-rated sleep quality were averaged across the week. Candidate mediators included health-related variables; stress; and emotional well-being assessed up to 13 times across 18 years from baseline to sleep study. RESULTS: Whites slept longer than other groups; the significant mediators were concurrent financial hardship and increasing number of stressors for Hispanics or Japanese versus whites. Whites had less WASO than blacks and Hispanics; significant mediators were concurrent number of health problems, physical inactivity, waist circumference, vasomotor symptoms, number of life stressors, and financial hardship, and increasing number of health problems from baseline to sleep study. Whites reported better sleep quality than blacks, Chinese, and Japanese; significant mediators were concurrent physical inactivity, vasomotor symptoms, positive affect, and depressive symptoms. CONCLUSIONS: Sleep differences between blacks or Hispanics versus whites were mediated by health problems, number of stressors, and financial hardship, whereas sleep differences between Chinese or Japanese versus whites were mediated by emotional well-being. This is the first study using formal mediational approaches.

Does Spinal Cord Stimulation Really Influence Sleep?

BACKGROUND: To date, clinical pain research has typically used subjective questionnaires to assess effectiveness of treatment. However, in the near future, new technologies may provide us objective outcome measures as an alternative to self-report. The goal of this study is to compare subjective and objective sleep assessments in a population of failed back surgery syndrome (FBSS) patients, treated with spinal cord stimulation (SCS). METHODS: Twenty-two patients diagnosed with FBSS received SCS. Sleep data was collected at three time point: prior to SCS implantation (B), one month after SCS (T1), and two months after SCS (T2). Sleep data measured by actigraphy provided objective sleep data and were compared to Pittsburgh sleep quality index (PSQI) scores. Agreement between sleep parameters, total sleep time (TST), sleep efficiency (SE), and sleep onset latency (SOL), was examined. RESULTS: Nineteen out of 22 patients completed the study. We identified significant differences between objective and subjective measurements for TST and SE at baseline and after two months of SCS, with patients underestimating both parameters on the PSQI in comparison to objective measurements. For SOL no significant differences were found, although patients subjectively overestimated SOL at B. CONCLUSION: The results about sleep measurements shown in this population of chronic pain patients, suggest that the subjective ratings scored worse than the objective measurements. Second, short-term SCS mainly seems to affect subjectively measured sleep parameters, especially SOL. This study shows the discrepancies between objective and subjective assessments in chronic pain research. Objective tools are indispensable for a correct assessment and treatment of sleep parameters. They are also playing a role as a biofeedback tool and are supporting the rehabilitation process.

Association of sleep with neurobehavioral impairments during inpatient rehabilitation after traumatic brain injury.

BACKGROUND: Sleep disturbance is a common sequela after traumatic brain injury (TBI). Many of the impairments following TBI may be exacerbated by impaired sleep-wake cycle regulation. OBJECTIVES: To investigate the relationship between total sleep time (TST), measured by wrist actigraphy and observational sleep logs, and neurobehavioral impairments during inpatient rehabilitation after TBI. METHODS: Twenty-five subjects undergoing inpatient rehabilitation for traumatic brain injury were included. TST was measured using wrist actigraphy and observational sleep logs. Neurobehavioral impairments were assessed using the Neurobehavioral Rating Scale-Revised (NRS-R), a multidimensional clinician-based assessment. RESULTS: Of 25 subjects enrolled, 23 subjects completed the study. A significant negative correlation was found between total NRS-R and TST calculated by observational sleep logs (r = -0.28, p = 0.007). The association between total NRS-R and TST, as calculated by actigraphy, was not significantly correlated (R = -0.01, p = 0.921). CONCLUSIONS: Sleep disturbance during inpatient rehabilitation is associated with neurobehavioral impairments after TBI. TST measured by actigraphy may be limited by sleep detection algorithms that have not been validated in certain patient populations. Considerations should be made regarding the feasibility of using wearable sensors in patients with cognitive and behavioral impairments. Challenges regarding actigraphy for sleep monitoring in the brain injury population are discussed.

New horizons in falls prevention.

Falls pose a major threat to the well-being and quality of life of older people. Falls can result in fractures and other injuries, disability and fear and can trigger a decline in physical function and loss of autonomy. This article synthesises recent published findings on fall risk and mobility assessments and fall prevention interventions and considers how this field of research may evolve in the future. Fall risk topics include the utility of remote monitoring using wearable sensors and recent work investigating brain activation and gait adaptability. New approaches for exercise for fall prevention including dual-task training, cognitive-motor training with exergames and reactive step training are discussed. Additional fall prevention strategies considered include the prevention of falls in older people with dementia and Parkinson's disease, drugs for fall prevention and safe flooring for preventing fall-related injuries. The review discusses how these new initiatives and technologies have potential for effective fall prevention and improved quality of life. It concludes by emphasising the need for a continued focus on translation of evidence into practice including robust effectiveness evaluations of so that resources can be appropriately targeted into the future.

High heritability of adolescent sleep-wake behavior on free, but not school days: a long-term twin study.

Adolescence development is characterized by significant changes in sleep biology. Despite an overall decline in sleep duration and a delay in bedtime, significant interindividual variation in sleep has been reported. The aim of the current study was to examine genetic and environmental influences on sleep in adolescence using long-term (6 month) actigraphy measurements, differentiating between school and free days. Sixteen monozygotic (n = 32) and 10 dizygotic (n = 20) twin pairs (mean age 12.8 ± 1.0 years; 25 females) participated in the study. Structural equation modeling was used to compute genetic, shared environmental and unique environmental contributors to sleep behavior. We found significantly more genetic influence on sleep timing (sleep midpoint; school: 14%, free: 90%) and duration (school: 15%; free: 68%) on free compared with school days. On the other hand, the genetic influence on measures of sleep quality (sleep efficiency and sleep onset latency) was high (>60%) and less dependent on the day of measurement. Only wake after sleep onset (WASO) exhibited a strong shared environmental influence (> 52%) on both school and free days, suggesting that behavioral/environmental interventions may help reduce WASO. In addition, self-reported chronotype was also highly genetically influenced (75%). Disrupted, ill-timed, and insufficient sleep in adolescence is associated with poor mental and physical health outcomes. Our findings of a strong genetic contribution to sleep in adolescence suggest that sleep may mark a genetic vulnerability to poor outcomes.

Circadian rhythm in idiopathic normal pressure hydrocephalus.

OBJECTIVES: The pathogenesis of idiopathic normal pressure hydrocephalus (iNPH) takes place in structures close to the cerebral ventricular system. Suprachiasmatic nucleus (SCN), situated close to the third ventricle, is involved in circadian rhythm. Diurnal disturbances are well-known in demented patients. The cognitive decline in iNPH is potentially reversible after a shunt operation. Diurnal rhythm has never been studied in iNPH. We hypothesize that there is a disturbance of circadian rhythm in iNPH-patients and the aim was to study any changes of the diurnal rhythm (mesor and circadian period) as well as any changes of the diurnal amplitude and acrophase of the activity in iNPH-patients before and after a shunt operation. PATIENTS AND METHODS: Twenty consecutive iNPH-patients fulfilling the criteria of the American iNPH-guidelines, 9 males and 11 females, mean age 73 (49-81) years were included. The patients underwent a pre-operative clinical work-up including 10m walk time (w10mt) steps (w10ms), TUG-time (TUGt) and steps (TUGs) and for cognitive function an MMSE score was measured. In order to receive circadian rhythm data actigraphic recordings were performed using the SenseWear 2 (BodyMedia Inc Pittsburgh, PA, USA) actigraph. Cosinor analyses of accelerometry data were performed in "R" using non-linear regression with Levenburg- Marquardt estimation. Pre- and post-operative data regarding mesor, amplitude and circadian period were compared using Wilcoxon-Mann-Whitney test for paired data. RESULTS: Twenty patients were evaluated before and three month post-operatively. Motor function (w10mt, w10ms, TUGt, TUGs) was significantly improved while MMSE was not significantly changed. Actigraphic measurements (mesor, amplitude and circadian period) showed no significant changes after shunt operation. CONCLUSION: This is the first systematic study of circadian rhythm in iNPH-patients. We found no significant changes in circadian rhythm after shunt surgery. The conceptual idea of diurnal rhythm changes in hydrocephalus is still interesting from a theoretical standpoint and warrants further studies that could include a combination of better designed actigraphic studies in combination with neuroendocrine markers and imaging methods.

Habitual sleep and kidney function in chronic kidney disease: the Chronic Renal Insufficiency Cohort study.

Physiological evidence suggests that sleep modulates kidney function. Our objective was to examine the cross-sectional association between kidney function and objectively-estimated habitual sleep duration, quality and timing in a cohort of patients with mild to moderate chronic kidney disease. This study involved two US clinical centers of the Chronic Renal Insufficiency Cohort (CRIC) study, including 432 participants in a CRIC ancillary sleep study. Habitual sleep duration, quality and timing were measured using wrist actigraphy for 5-7 days. Validated sleep questionnaires assessed subjective sleep quality, daytime sleepiness and risk of sleep apnea. Kidney function was assessed with the estimated glomerular filtration rate using the Chronic Kidney Disease Epidemiology Collaboration equation, and the urinary protein to creatinine ratio. Lower estimated glomerular filtration rate was associated with shorter sleep duration (-1.1 mL min-1  1.73 m-2 per hour less sleep, P = 0.03), greater sleep fragmentation (-2.6 mL min-1  1.73 m-2 per 10% higher fragmentation, P < 0.001) and later timing of sleep (-0.9 mL min-1  1.73 m-2 per hour later, P = 0.05). Higher protein to creatinine ratio was also associated with greater sleep fragmentation (approximately 28% higher per 10% higher fragmentation, P < 0.001). Subjective sleep quality, sleepiness and persistent snoring were not associated with estimated glomerular filtration rate or protein to creatinine ratio. Thus, worse objective sleep quality was associated with lower estimated glomerular filtration rate and higher protein to creatinine ratio. Shorter sleep duration and later sleep timing were also associated with lower estimated glomerular filtration rate. Physicians treating patients with chronic kidney disease should consider inquiring about sleep and possibly sending for clinical sleep assessment. Longitudinal and interventional trials are needed to understand causal direction.

Naturally occurring circadian rhythm and sleep duration are related to executive functions in early adulthood.

Experimental sleep deprivation studies suggest that insufficient sleep and circadian misalignment associates with poorer executive function. It is not known whether this association translates to naturally occurring sleep patterns. A total of 512 of full-term-born members of the Arvo Ylppö Longitudinal Study [mean age = 25.3, standard deviation (SD) = 0.65] (44.3% men) wore actigraphs to define sleep duration, its irregularity and circadian rhythm (sleep mid-point) during a 1-week period (mean 6.9 nights, SD = 1.7). Performance-based executive function was assessed with the Trail-Making Test, Conners' Continuous Performance Test and Stroop. The self-rated adult version of Behavior Rating Inventory of Executive Function was used to assess trait-like executive function. We found that performance-based and self-reported trait-like executive function correlated only modestly (all correlations ≤0.17). Shorter sleep duration associated with more commission errors. Later circadian rhythm associated with poorer trait-like executive function, as indicated by the Brief Metacognitive Index and the Behavior Regulation Index. Those belonging to the group with the most irregular sleep duration performed slower than others in the Trail-Making Test Part A. All associations were adjusted for sex, age, socioeconomic status and body mass index. In conclusion, naturally occurring insufficient sleep and later circadian rhythm showed modest associations with poorer executive function. Shorter habitual sleep duration was associated with lower scores of performance-based tests of executive function, and later circadian rhythm was associated mainly with poorer trait-like executive function characteristics. Our findings suggest additionally that sleep duration and circadian rhythm associate with different domains of executive function, and there are no additive effects between the two.

Variability of activity patterns across mood disorders and time of day.

BACKGROUND: Few actigraphy studies in mood disorders have simultaneously included unipolar (UP) and bipolar (BD) depression or BD mixed states as a separate subgroup from mania. This study compared objectively measured activity in UP, BD depression, mania and mixed states and examined if patterns differed according to time of day and/or diagnostic group. METHODS: Eighty -eight acutely admitted inpatients with mood disorders (52 UP; 18 mania; 12 BD depression; 6 mixed states) underwent 24 hours of actigraphy monitoring. Non-parametric analyses were used to compare median activity level over 24 h (counts per minute), two time series (64-min periods of continuous motor activity) in the morning and evening, and variability in activity across and within groups. RESULTS: There was no between-group difference in 24-h median level of activity, but significant differences emerged between BD depression compared to mania in the active morning period, and between UP and mania and mixed states in the active evening period. Within-group analyses revealed that UP cases showed several significant changes between morning and evening activity, with fewer changes in the BD groups. CONCLUSIONS: Mean activity over 24 hours has limited utility in differentiating UP and BD. In contrast, analysis of non-linear variability measures of activity at different times of day could help objectively distinguish between mood disorder subgroups. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01415323 , first registration July 6, 2011.

Rest-activity rhythms in small scale homelike care and traditional care for residents with dementia.

BACKGROUND: An enriched environment for residents with dementia may have a positive effect on the rest-activity rhythm. A small scaled homelike special care unit might be such an enriched environment. The present study shows whether the rest-activity rhythm of residents with moderate to severe dementia responds positively to a transfer from a regular Special Care Unit (SCU) to a small scaled homelike SCU. METHODS: Initially, a group of 145 residents living in a regular SCU participated. Out of this group, 77 residents moved to a small scaled homelike SCU. This group was compared to the group of 68 residents that remained at the regular SCU. Rest-activity rhythm was assessed by means of actigraphy and observation scales before and after relocation. RESULTS: No significant main effects nor significant interaction effects in intradaily and interdaily activity were found for the data of 38 residents in the small scaled homelike SCU and 20 residents of the regular SCU. The effect sizes, however, ranged from small to large. CONCLUSIONS: Considering the effect sizes, a new study with a larger number of participants is necessary before firm conclusions can be drawn. TRIAL REGISTRATION: Current Controlled Trials ISRCTN11151241 . registration date: 21-06-2017. Retrospectively registered.

How consumer physical activity monitors could transform human physiology research.

A sedentary lifestyle and lack of physical activity are well-established risk factors for chronic disease and adverse health outcomes. Thus, there is enormous interest in measuring physical activity in biomedical research. Many consumer physical activity monitors, including Basis Health Tracker, BodyMedia Fit, DirectLife, Fitbit Flex, Fitbit One, Fitbit Zip, Garmin Vivofit, Jawbone UP, MisFit Shine, Nike FuelBand, Polar Loop, Withings Pulse O2, and others have accuracies similar to that of research-grade physical activity monitors for measuring steps. This review focuses on the unprecedented opportunities that consumer physical activity monitors offer for human physiology and pathophysiology research because of their ability to measure activity continuously under real-life conditions and because they are already widely used by consumers. We examine current and potential uses of consumer physical activity monitors as a measuring or monitoring device, or as an intervention in strategies to change behavior and predict health outcomes. The accuracy, reliability, reproducibility, and validity of consumer physical activity monitors are reviewed, as are limitations and challenges associated with using these devices in research. Other topics covered include how smartphone apps and platforms, such as the Apple ResearchKit, can be used in conjunction with consumer physical activity monitors for research. Lastly, the future of consumer physical activity monitors and related technology is considered: pattern recognition, integration of sleep monitors, and other biosensors in combination with new forms of information processing.

[Quantified self movement--the new mantra of life insurance companies]. / Quantified Self Movement--das neue Mantra der Lebensversicherer.

Wearables are small personal minicomputers that register biometric data. In such a way, the insurance industry hopes to create new sales opportunities and products, and simplify underwriting. Lower premiums will promote the use of wearables. The related possibilities and unanswered questions are discussed in this article. Utilisation of big data offers the insurance industry a range of new opportunities. The benefit must be proven in the future, however.