A validation of wrist actigraphy against polysomnography in patients with schizophrenia or bipolar disorder

Sleep and physical activity patterns in relation to daily-life symptoms in psychosis: An actigraphy and experience sampling study

Sleep disturbances and reduced physical activity (PA) are important risk factors for poor physical and mental health outcomes in people with psychosis. However, the precise interrelations between sleep, PA and psychopathology remain unclear. This study combined experience sampling (ESM) and actigraphy in thirty-two patients with a schizophrenia spectrum disorder to investigate interrelations of day-to-day variations in actigraphic estimates of PA and sleep and psychotic and affective symptoms. Multilevel mixed-models show that subjects reported more positive affect on more physically active days. Unexpectedly, participants reported worse next-day negative affect and/or psychotic symptoms after nights with higher sleep continuity, as consistently indicated by sleep efficiency and the mean duration of bouts of wake and sleep. Lastly, PA was higher after nights with higher sleep continuity and shorter total sleep duration. These results highlight that modifiable lifestyle factors such as PA and sleep have an intricate, but clinically relevant relationship with psychotic and affective symptoms. Future studies are needed to further examine the complex effects of these behaviors in order to develop effective, targeted treatment strategies to improve clinical outcome in psychosis.

A systematic review of passive data for remote monitoring in psychosis and schizophrenia

There is increasing use of digital tools to monitor people with psychosis and schizophrenia remotely, but using this type of data is challenging. This systematic review aimed to summarise how studies processed and analysed data collected through digital devices. In total, 203 articles collecting passive data through smartphones or wearable devices, from participants with psychosis or schizophrenia were included in the review. Accelerometers were the most common device (n = 115 studies), followed by smartphones (n = 46). The most commonly derived features were sleep duration (n = 50) and time spent sedentary (n = 41). Thirty studies assessed data quality and another 69 applied data quantity thresholds. Mixed effects models were used in 21 studies and time-series and machine-learning methods were used in 18 studies. Reporting of methods to process and analyse data was inconsistent, highlighting a need to improve the standardisation of methods and reporting in this area of research.

The behavioral and physiological correlates of affective mood switching in premenstrual dysphoric disorder

Premenstrual dysphoric disorder (PMDD), a more severe manifestation of premenstrual syndrome (PMS), is characterized by emotional, behavioral, and physical symptoms that begin in the mid-to-late luteal phase of the menstrual cycle, when estradiol and progesterone levels precipitously decline, and remit after the onset of menses. Remotely monitoring physiologic variables associated with PMDD depression symptoms, such as heart rate variability (HRV), sleep, and physical activity, holds promise for developing an affective state prediction model. Switching into and out of depressive states is associated with an increased risk of suicide, and therefore, monitoring periods of affective switching may help mitigate risk. Management of other chronic health conditions, including cardiovascular disease and diabetes, has benefited from remote digital monitoring paradigms that enable patients and physicians to monitor symptoms in real-time and make behavioral and medication adjustments. PMDD is a chronic condition that may benefit from real-time, remote monitoring. However, clinical practice has not advanced to monitoring affective states in real-time. Identifying remote monitoring paradigms that can detect within-person affective state change may help facilitate later research on timely and efficacious interventions for individuals with PMDD. This narrative review synthesizes the current literature on behavioral and physiological correlates of PMDD suitable for remote monitoring during the menstrual cycle. The reliable measurement of heart rate variability (HRV), sleep, and physical activity, with existing wearable technology, suggests the potential of a remote monitoring paradigm in PMDD and other depressive disorders.

Revisiting Cognitive Deficits in Outpatients with Psychotic Disorders: A Transdiagnostic Comparison of Cognitive Performance While Accounting for Putative Confounding Factors

Recent research suggests that cognitive deficits in individuals with psychotic disorders could be overestimated because poor cognitive test performance is partly attributable to non-cognitive factors. To further test this, we included non-hospitalized individuals with psychotic disorders (PSY, n = 38), individuals with attenuated psychotic symptoms (n = 40), individuals with obsessive-compulsive disorders (n = 39), and healthy controls (n = 38). Relevant cognitive domains were assessed using the MATRICS Consensus Cognitive Battery. Putative confounding non-cognitive factors-heart rate, self-reported stress, negative affect, performance-related beliefs, and actigraphy-derived sleep-were assessed before cognitive testing. A multivariate analysis of covariance was calculated to examine group differences in cognitive performance while controlling for non-cognitive factors. PSY showed decreased test performance in graphomotor speed, attention, and verbal tasks compared to the other groups, whereas non-verbal/visual-spatial tasks were unimpaired. After accounting for non-cognitive factors, group differences diminished in verbal learning, whereas differences in the other domains remained significant. Against our hypotheses, the present findings indicate that some cognitive deficits in PSY cannot be attributed to momentary confounding factors.

Combining actigraphy and experience sampling to assess physical activity and sleep in patients with psychosis: A feasibility study

BACKGROUND

Sleep disorders and reduced physical activity are common in patients with psychosis and can be related to health-related outcomes such as symptomatology and functioning. Mobile health technologies and wearable sensor methods enable continuous and simultaneous monitoring of physical activity, sleep, and symptoms in one's day-to-day environment. Only a few studies have applied simultaneous assessment of these parameters. Therefore, we aimed to examine the feasibility of the simultaneous monitoring of physical activity, sleep, and symptoms and functioning in psychosis.

METHODS

Thirty three outpatients diagnosed with a schizophrenia or other psychotic disorder used an actigraphy watch and experience sampling method (ESM) smartphone app for 7 consecutive days to monitor physical activity, sleep, symptoms, and functioning. Participants wore the actigraphy watch during day and night and completed multiple short questionnaires (eight daily, one morning, and one evening) on their phone. Hereafter they completed evaluation questionnaires.

RESULTS

Of the 33 patients (25 male), 32 (97.0%) used the ESM and actigraphy during the instructed timeframe. ESM response was good: 64.0% for the daily, 90.6% for morning, and 82.6% for evening questionnaire(s). Participants were positive about the use of actigraphy and ESM.

CONCLUSION

The combination of wrist-worn actigraphy and smartphone-based ESM is feasible and acceptable in outpatients with psychosis. These novel methods can help both clinical practice and future research to gain more valid insight into physical activity and sleep as biobehavioral markers linked to psychopathological symptoms and functioning in psychosis. This can be used to investigate relationships between these outcomes and thereby improve individualized treatment and prediction.

Quality Evaluation of Free-living Validation Studies for the Assessment of 24-Hour Physical Behavior in Adults via Wearables: Systematic Review

Background

Wearable technology is a leading fitness trend in the growing commercial industry and an established method for collecting 24-hour physical behavior data in research studies. High-quality free-living validation studies are required to enable both researchers and consumers to make guided decisions on which study to rely on and which device to use. However, reviews focusing on the quality of free-living validation studies in adults are lacking.

Objective

This study aimed to raise researchers’ and consumers’ attention to the quality of published validation protocols while aiming to identify and compare specific consistencies or inconsistencies between protocols. We aimed to provide a comprehensive and historical overview of which wearable devices have been validated for which purpose and whether they show promise for use in further studies.

Methods

Peer-reviewed validation studies from electronic databases, as well as backward and forward citation searches (1970 to July 2021), with the following, required indicators were included: protocol must include real-life conditions, outcome must belong to one dimension of the 24-hour physical behavior construct (intensity, posture or activity type, and biological state), the protocol must include a criterion measure, and study results must be published in English-language journals. The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool with 9 questions separated into 4 domains (patient selection or study design, index measure, criterion measure, and flow and time).

Results

Of the 13,285 unique search results, 222 (1.67%) articles were included. Most studies (153/237, 64.6%) validated an intensity measure outcome such as energy expenditure. However, only 19.8% (47/237) validated biological state and 15.6% (37/237) validated posture or activity-type outcomes. Across all studies, 163 different wearables were identified. Of these, 58.9% (96/163) were validated only once. ActiGraph GT3X/GT3X+ (36/163, 22.1%), Fitbit Flex (20/163, 12.3%), and ActivPAL (12/163, 7.4%) were used most often in the included studies. The percentage of participants meeting the quality criteria ranged from 38.8% (92/237) to 92.4% (219/237). On the basis of our classification tree to evaluate the overall study quality, 4.6% (11/237) of studies were classified as low risk. Furthermore, 16% (38/237) of studies were classified as having some concerns, and 72.9% (173/237) of studies were classified as high risk.

Conclusions

Overall, free-living validation studies of wearables are characterized by low methodological quality, large variability in design, and focus on intensity. Future research should strongly aim at biological state and posture or activity outcomes and strive for standardized protocols embedded in a validation framework. Standardized protocols for free-living validation embedded in a framework are urgently needed to inform and guide stakeholders (eg, manufacturers, scientists, and consumers) in selecting wearables for self-tracking purposes, applying wearables in health studies, and fostering innovation to achieve improved validity.

Comparing polysomnography, actigraphy, and sleep diary in the home environment: The Study of Women's Health Across the Nation (SWAN) Sleep Study

Study Objectives

Polysomnography (PSG) is considered the "gold standard" for assessing sleep, but cost and burden limit its use. Although wrist actigraphy and self-report diaries are feasible alternatives to PSG, few studies have compared all three modalities concurrently across multiple nights in the home to assess their relative validity across multiple sleep outcomes. This study compared sleep duration and continuity measured by PSG, actigraphy, and sleep diaries and examined moderation by race/ethnicity.

Methods

Participants from the Study of Women's Health Across the Nation (SWAN) Sleep Study included 323 White (n = 147), African American (n = 120), and Chinese (n = 56) middle-aged community-dwelling women (mean age: 51 years, range: 48-57). PSG, wrist actigraphy (AW-64; Philips Respironics, McMurray, PA), and sleep diaries were collected concurrently in participants' homes over three consecutive nights. Multivariable repeated-measures linear models compared time in bed (TIB), total sleep time (TST), sleep efficiency (SE), sleep latency (SL), and wake after sleep onset (WASO) across modalities.

Results

Actigraphy and PSG produced similar estimates of sleep duration and efficiency. Diaries yielded higher estimates of TIB, TST, and SE versus PSG and actigraphy, and lower estimates of SL and WASO versus PSG. Diary SL was shorter than PSG SL only among White women, and diary WASO was lower than PSG and actigraphy WASO among African American versus White women.

Conclusions

Given concordance with PSG, actigraphy may be preferred as an alternative to PSG for measuring sleep in the home. Future research should consider racial/ethnic differences in diary-reported sleep continuity.

Toward a Digital Future in Bipolar Disorder Assessment: A Systematic Review of Disruptions in the Rest-Activity Cycle as Measured by Actigraphy

BACKGROUND

Disruptions in rest and activity patterns are core features of bipolar disorder (BD). However, previous methods have been limited in fully characterizing the patterns. There is still a need to capture dysfunction in daily activity as well as rest patterns in order to more holistically understand the nature of 24-h rhythms in BD. Recent developments in the standardization, processing, and analyses of wearable digital actigraphy devices are advancing longitudinal investigation of rest-activity patterns in real time. The current systematic review aimed to summarize the literature on actigraphy measures of rest-activity patterns in BD to inform the future use of this technology.

METHODS

A comprehensive systematic review using PRISMA guidelines was conducted through PubMed, MEDLINE, PsycINFO, and EMBASE databases, for papers published up to February 2021. Relevant articles utilizing actigraphy measures were extracted and summarized. These papers contributed to three research areas addressed, pertaining to the nature of rest-activity patterns in BD, and the effects of therapeutic interventions on these patterns.

RESULTS

Seventy articles were included. BD was associated with longer sleep onset latency and duration, particularly during depressive episodes and with predictive value for worsening of future manic symptoms. Lower overall daily activity was also associated with BD, especially during depressive episodes, while more variable activity patterns within a day were seen in mania. A small number of studies linked these disruptions with differential patterns of brain functioning and cognitive impairments, as well as more adverse outcomes including increased suicide risk. The stabilizing effect of therapeutic options, including pharmacotherapies and chronotherapies, on activity patterns was supported.

CONCLUSION

The use of actigraphy provides valuable information about rest-activity patterns in BD. Although results suggest that variability in rhythms over time may be a specific feature of BD, definitive conclusions are limited by the small number of studies assessing longitudinal changes over days. Thus, there is an urgent need to extend this work to examine patterns of rhythmicity and regularity in BD. Actigraphy research holds great promise to identify a much-needed specific phenotypic marker for BD that will aid in the development of improved detection, treatment, and prevention options.

A Study of Factors Causing Sleep State Misperception in Patients with Depression

PURPOSE

Sleep state misperception, which is the discrepancy between subjective and objective sleep, is often observed in patients with depression. This phenomenon may delay the remission of depression. Previous studies have focused on the total sleep time (TST) misperception, with many of these studies using actigraphy. Thus, our study investigated depressed patients with the exploratory aim of clarifying factors associated with the sleep state misperception including the wake after sleep onset (WASO) misperception, with their objective sleep additionally evaluated by polysomnography (PSG).

PATIENTS AND METHODS

We conducted a cross-sectional study. Before undergoing overnight PSG monitoring, 40 patients with depression completed questionnaires that included the Beck Depression Inventory (BDI), Epworth sleepiness scale, Temperament and Character Inventory, and the Pittsburgh sleep quality index. Patients were also asked to estimate their subjective sleep duration after they woke up in the morning. Based on this data, we calculated the misperception using the following formula: subjective sleep duration minus objective sleep duration. We compared each factor between negative and positive misperception groups and the multiple regression analysis was performed for TST and WASO misperception, respectively.

RESULTS

Although sleep architectures, age, severity of depression and obstructive sleep apnea (OSA) exhibited differences in underestimating or overestimating the WASO, only sex differences were associated with underestimating or overestimating their total sleep time (TST). Moreover, BDI, the severity of OSA, sleep architectures (N1% and N2%), and benzodiazepine (BZD) use were significantly correlated with WASO misperception, whereas only OSA severity was significantly correlated with TST misperception. A subsequent multiple regression analysis demonstrated the BDI was independently correlated with the WASO misperception (β=0.341, p=0.049).

CONCLUSION

In clinical practice, interventions especially for OSA, and the reduction of depressive symptoms are an important method for improving patient sleep perception. Moreover, current results suggest that BZD prescriptions should be avoided as well.

Relevance of Objective Measures in Psychiatric Disorders-Rest-Activity Rhythm and Psychophysiological Measures

PURPOSE OF REVIEW

We present a review of recent methods of objective measurement in psychiatry and psychology with a focus on home monitoring and its utility in guiding treatment.

RECENT FINDINGS

For individualized diagnostics and treatment of insomnia, actigraphy can generate clinically useful graphical presentations of sleep timing and patterns. Psychophysiological measures may complement psychometrics by tracking parallel changes in physiological responses and emotional functioning, especially during therapy for trauma symptoms and emotion regulation. It seems that rather than defining universal cut-offs, an individualised range of variability could characterize treatment response. Wearable actigraphy and psychophysiological sensors are promising devices to provide biofeedback and guide treatment. Use of feasible and reliable technology during experimental and clinical procedures may necessitate defining healthy and abnormal responses in different populations and pathological states. We present a "call for action" towards further collaborative work to enable large scale use of objective measures.

Loneliness and sleep in the American Indian Blackfeet community

BACKGROUND

Sleep is largely understudied in American Indians (AIs), even though sleep is implicated in the chronic diseases which disproportionately affect AI communities.

OBJECTIVE

To investigate relationships between daily self-reported loneliness and sleep as measured with actigraphy.

METHODS

In a sample of 98 Blackfeet adults living on the Blackfeet reservation in Montana, we used Ecological Momentary Assessment and actigraphy over a week-long period to investigate relationships between loneliness and sleep. Loneliness was measured daily using the Short Loneliness Scale and actigraphy was used to measure total sleep time, sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE).

RESULTS

Using a series of generalized linear mixed-effects models controlling for demographic characteristics, anxiety and depressive symptoms, and adverse childhood experiences, we found that those who were lonelier had higher WASO and SOL, and lower SE relative to those who were less lonely. Within-subject effects indicate that participants who were lonelier for a given day relative to their own weekly average had higher WASO that night relative to their own weekly average.

CONCLUSIONS

Our findings provide initial preliminary evidence suggesting that loneliness may be a psychosocial factor which contributes to poor sleep in AI communities.

Diagnostic value of actigraphy in hypersomnolence disorders

OBJECTIVE

Differentiating between the central hypersomnias presents a challenge to the diagnosis of patients with hypersomnolence. Actitigraphy may support efforts to distinguish them. We aimed to evaluate: 1) the ability of actigraphy to quantify sleep continuity measures in comparison with polysomnography in patients with hypersomnolence; 2) whether actigraphy can distinguish patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid from patients with narcolepsy type 1 and from sleep-healthy controls; and 3) the distinct activity profiles and circadian rhythms of patients with narcolepsy type 1, patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid, and sleep-healthy controls.

METHOD

Polysomnography, multiple sleep latency tests and actigraphy were conducted in 14 patients with narcolepsy type 1, 29 patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid and 15 sleep-healthy controls.

RESULTS

Actigraphy quantified several sleep continuity measures consistently with polysomnography in all the patients. Actigraphy distinguished patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid from patients with narcolepsy type 1 and sleep-healthy controls. Patients with narcolepsy type 1 had poor sleep quality and altered circadian rest-activity rhythm compared with controls.

CONCLUSION

Actigraphy is an adequate tool for establishing the amount of night sleep and supports the differential diagnosis of patients with hypersomnolence.

"Assessing the Psychometric Properties of the PROMIS Sleep Measures in Persons with Psychosis."

An accumulation of research has indicated that persons with psychotic disorders experience a variety of sleep disturbances. However, few studies have examined the psychometric properties of sleep assessments that are utilized in this population. We conducted two studies to examine the reliability and validity of the PROMISTM Sleep Disturbance and Sleep-Related Impairment scales in outpatient samples of persons with psychosis. In Study 1, we examined the internal consistency and convergent validity of the PROMIS sleep scales in individuals with various psychotic disorders (N = 98) and healthy controls (N = 22). The PROMIS sleep scales showed acceptable internal consistency and convergent validity in both healthy controls and individuals with psychotic disorders. In addition, replicating prior research, the PROMIS scales identified greater sleep disturbance and sleep-related impairment in participants with psychotic disorders compared to healthy controls. In Study 2, we examined the test-retest reliability (M = 358 days) of the PROMIS sleep scales in a subset (N = 37) of persons with psychotic disorders who previously participated in Study 1. We also assessed the relation between these self-report measures and actigraph sleep parameters. The results showed that PROMIS sleep measures demonstrated modest temporal stability in the current sample. Contrary to our hypothesis, there was a lack of correspondence between these scales and actigraph sleep parameters. Overall, these findings indicate that the PROMIS sleep scales are psychometrically sound measures for populations with psychosis and highlight the importance of utilizing a multi-method approach to assess sleep.

Sleep disturbances and cognitive impairment in schizophrenia spectrum disorders: a systematic review and narrative synthesis

Individuals with schizophrenia spectrum disorders (SSD) experience frequent sleep disturbances in addition to enduring cognitive impairments. The purpose of the present review was to systematically summarise our current understanding of the association between sleep disturbances and cognition in SSD. Through this, it was aimed to identify features of disturbed sleep that are reliably associated with cognitive deficits in SSD and identify the gaps within the current literature that require future investigation. Eighteen relevant studies were identified following a two-stage screening process. Following a structured narrative synthesis of key study components, no clear and consistent pattern emerged. Considerable methodological variability was present amongst the reviewed studies. Although some broad consistencies were identified, such as associations between sleep spindle density and sleep-dependent memory consolidation, the overall pattern of results lacked a cohesive composition due to the diverse list of sleep parameters and cognitive domains investigated, as well as a lack of replication. Additional research is needed before more definitive remarks can be made regarding the influence of sleep disturbances on cognitive function in SSD.

Misperception of sleep in bipolar disorder: an exploratory study using questionnaire versus actigraphy

Background

The concept of misperception of sleep refers to the estimated discrepancy between subjective and objective measures of sleep. This has been assessed only in a few prior studies in individuals with Bipolar Disorder (BD) as compared to Healthy Controls (HC) and with mixed results.

Methods

We assessed a sample of 133 euthymic individuals with BD and 63 HC for retrospective subjective (Pittsburgh Sleep Quality Index) and objective (21 days of actigraphy recording) measures of total sleep time, sleep latency and sleep efficiency. We first investigated the correlations between these subjective and objective measures in the two groups. We then compared individuals with BD and HC for the absolute values of the differences between subjective and objective sleep parameters, used as a proxy of the magnitude of misperception of sleep. Finally, we undertook regression analyses to assess associations between clinical groups, core demographics, clinical factors and misperception of sleep.

Results

The correlation coefficients between subjective and objective measures of sleep did not differ between groups (total sleep time: rho = .539 in BD and rho = .584 in HC; sleep latency: rho = .190 in BD and rho = .125 in HC; sleep efficiency: rho = .166 in BD and rho = .222 in HC). Individuals with BD did not differ from HC in the magnitude of misperception of total sleep time, sleep latency nor sleep efficiency. Individuals with BD type 1 misperceived their sleep efficiency significantly more than individuals with BD type 2, with no further difference between BD type 1 and BD type 2 regarding sleep latency and sleep duration misperceptions. Three factors (age, symptoms of obstructive sleep apnea, and mild depressive symptoms), were the main contributors to the magnitude of misperception of sleep.

Conclusions

Misperception of sleep was not associated with a diagnosis of BD. In this sample, mild depressive symptoms, older age, or symptoms of obstructive sleep apnea may be related to greater sleep misperception. In that case, the reliability of subjective measures may decrease as the misperception of sleep increases. This study may help guide clinicians in selecting the best approach for assessing sleep (objective versus subjective measures) in individuals with BD.

The Association between Sleep Duration and Quality with Readmissions: An Exploratory Pilot-Study among Cardiology Inpatients

Background: Readmissions within 30 days of discharge are prominent among patients with cardiovascular disease. Post hospital syndrome hypothesizes that sleep disturbance during the index admission contributes to an acquired transient vulnerability, leading to increased risk of readmission. This study evaluated the association of in-hospital sleep (a) duration and (b) quality with 30-day all-cause unplanned readmission. Methods: This prospective observational cohort study included patients admitted to the coronary care unit of a South Australian hospital between 2016–2018. Study participants were invited to wear an ActiGraph GT3X+ for the duration of their admission and for two weeks post-discharge. Validated sleep and quality of life questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), were administered. Readmission status and questionnaires were assessed at 30 days post-discharge via patient telephone interview and a review of hospital records. Results: The final cohort consisted of 75 patients (readmitted: n = 15, non-readmitted: n = 60), of which 72% were male with a mean age 66.9 ± 13.1 years. Total sleep time (TST), both in hospital (6.9 ± 1.3 vs. 6.8 ± 2.9 h, p = 0.96) and post-discharge (7.4 ± 1.3 h vs. 8.9 ± 12.6 h, p = 0.76), was similar in all patients. Patient’s perception of sleep, reflected by PSQI scores, was poorer in readmitted patients (9.13 ± 3.6 vs. 6.4 ± 4.1, p = 0.02). Conclusions: Although an association between total sleep time and 30-day readmission was not found, patients who reported poorer sleep quality were more likely to be readmitted within 30 days. This study also highlighted the importance of improving sleep, both in and out of the hospital, to improve the outcomes of cardiology inpatients.

Sleep and Circadian Rhythm Disturbance in Remitted Schizophrenia and Bipolar Disorder: A Systematic Review and Meta-analysis

BACKGROUND

Sleep and circadian rhythm disturbances in schizophrenia are common, but incompletely characterized. We aimed to describe and compare the magnitude and heterogeneity of sleep-circadian alterations in remitted schizophrenia and compare them with those in interepisode bipolar disorder.

METHODS

EMBASE, Medline, and PsycINFO were searched for case-control studies reporting actigraphic parameters in remitted schizophrenia or bipolar disorder. Standardized and absolute mean differences between patients and controls were quantified using Hedges' g, and patient-control differences in variability were quantified using the mean-scaled coefficient of variation ratio (CVR). A wald-type test compared effect sizes between disorders.

RESULTS

Thirty studies reporting on 967 patients and 803 controls were included. Compared with controls, both schizophrenia and bipolar groups had significantly longer total sleep time (mean difference [minutes] [95% confidence interval {CI}] = 99.9 [66.8, 133.1] and 31.1 [19.3, 42.9], respectively), time in bed (mean difference = 77.8 [13.7, 142.0] and 50.3 [20.3, 80.3]), but also greater sleep latency (16.5 [6.1, 27.0] and 2.6 [0.5, 4.6]) and reduced motor activity (standardized mean difference [95% CI] = -0.86 [-1.22, -0.51] and -0.75 [-1.20, -0.29]). Effect sizes were significantly greater in schizophrenia compared with the bipolar disorder group for total sleep time, sleep latency, and wake after sleep onset. CVR was significantly elevated in both diagnoses for total sleep time, time in bed, and relative amplitude.

CONCLUSIONS

In both disorders, longer overall sleep duration, but also disturbed initiation, continuity, and reduced motor activity were found. Common, modifiable factors may be associated with these sleep-circadian phenotypes and advocate for further development of transdiagnostic interventions that target them.

A systematic review of the accuracy of sleep wearable devices for estimating sleep onset

The accurate estimation of sleep onset is required for many purposes, including the administration of a behavioural treatment for insomnia called Intensive Sleep Retraining, facilitating power naps, and conducting objective daytime sleepiness tests. Specialised equipment and trained individuals are presently required to administer these applications in the laboratory: a costly and impractical procedure which limits their utility in practice. A wearable device could be used to administer these applications outside the laboratory, increasing accessibility. This systematic review aimed to identify practical wearable devices that accurately estimate sleep onset. The search strategy identified seventy-one articles which compared estimations of sleep onset latency from wearable devices against polysomnography (PSG). Actigraphy devices produced average estimations of sleep onset latency that were often not significantly different from PSG, but there was large inter-individual variability depending on participant characteristics. As expected, electroencephalography-based devices produced more accurate and less variable estimates. Devices that measured behavioural aspects of sleep onset consistently overestimated PSG-determined sleep onset latency, but to a comparatively low degree. This sleep measurement method could be deployed in a simple wearable device to accurately estimate sleep onset and administer Intensive Sleep Retraining, power naps, and objective daytime sleepiness tests outside the laboratory setting.

Pineal gland and schizophrenia: A systematic review and meta-analysis

Melatonin (MLT), the main hormone of the pineal gland (PG), is assumed to support initiation and maintenance of sleep, and a stable sleep-wake cycle, exerting antioxidative and neuroprotective actions. Evidence demonstrates that sleep and circadian rhythm abnormalities are very common in schizophrenia patients. Some imaging studies suggest structural abnormalities of the PG in these patients as well. We aimed to critically appraise the literature on PG imaging and melatonin secretion in schizophrenia patients, in comparison to matched healthy controls, and to review placebo-controlled trials of add-on exogenous MLT treatment in schizophrenia patients. In this systematic review, twenty-nine studies were included. Meta-analytical evaluation of data was possible only for MLT secretion finding that midnight plasma levels were significantly reduced in individuals with schizophrenia as compared to healthy controls (Hedge`s g = 1.32, p < 0.01). Imaging studies demonstrated greater prevalence of enlarged calcifications (>1 cm) of the PG (2 out of 2 computed tomography studies) and smaller PG volume (2 out of 3 magnetic resonance studies) compared with healthy controls. Anatomic and functional abnormalities of the PG were not associated with duration of illness or with treatment factors, maybe suggesting them to be primary characteristics of the disease and genetically based. Add-on MLT treatment leads to a modest improvement of objective and subjective sleep quality, of metabolic adverse effects of antipsychotics, and of tardive dyskinesia symptoms in schizophrenia patients. It remains to be established whether MLT treatment in prodromal phases of the disease could prevent neurostructural abnormalities.

Agreement between actigraphic and polysomnographic measures of sleep in adults with and without chronic conditions: A systematic review and meta-analysis

Wrist actigraphy (ACT) may overestimate sleep and underestimate wake, and the agreement may be lower in people with chronic conditions who often have poor sleep and low activity levels. The purpose of this systematic review is to compare the agreement between ACT and polysomnographic (PSG) measures of sleep in adults without chronic conditions and sleep complaints (healthy) and with chronic conditions. We conducted a systematic review and meta-analysis using PRISMA guidelines. We searched PubMed, OVIDEMBASE, OVIDMEDLINE, OVIDPsycINFO, CENTRAL, CINAHL, ClinicalTrials.gov, International Clinical Trials Registry, and Open Grey. We included 96 studies with a total of 4134 participants, of whom 762 (18.4) were healthy adults and 724 (17.5%) were adults with chronic conditions. Among adults with chronic conditions, ACT overestimated TST, compared to PSG [M = 22.42 min (CI 95%: 11.92, 32.91 min)] and SE [M = 5.21% (CI 95%: 1.41%-9.00%)]. ACT underestimated SOL [M = -7.70 min (CI 95%: -15.22, -0.18 min)], and WASO [M = -10.90 min (CI 95%: -26.01, 4.22 min)]. These differences were consistently larger between ACT and PSG sleep measures compared to healthy adults. Research is needed to better understand factors that influence the agreement between ACT and PSG among people with chronic conditions.

Assessment of diurnal melatonin, cortisol, activity, and sleep-wake cycle in patients with and without diabetic retinopathy

OBJECTIVE

To assess the diurnal melatonin, cortisol, and activity/rest levels, as well as sleep quality, in patients with and without nonproliferative diabetic retinopathy (DR).

METHODS

We included 25 diabetic patients with DR and 29 without DR. A total of 21 healthy subjects constituted the control group. We assessed the circadian rhythm by actigraphy and diurnal salivary melatonin and cortisol measurements. Sleep quality was evaluated by actigraphy and the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaires. Light exposure was quantified by actigraphy. The primary outcome was peak salivary melatonin level. Secondary outcomes were mean melatonin and cortisol levels during dark hours, activity-rest rhythm, sleep quality, as well as level of white, red, green, and blue light exposure.

RESULTS

Peak melatonin concentration at 04:00 and mean nocturnal melatonin level were significantly reduced in all diabetic patients, regardless of retinopathy stage (p < 0.001). Levels of light exposures during dark hours were not significantly different in patients with and without DR and healthy controls. Only patients with DR showed increased intradaily variability in their activity-rest interval, indicating circadian misalignment (p = 0.04). Neither the objective actigraphic sleep quality parameters nor the subjective PSQI or ESS scores were significantly different between healthy controls and diabetic patients.

CONCLUSIONS

Reduced nocturnal melatonin concentration and increased fragmentation of activity-rest intervals revealed circadian rhythm disturbance in diabetic patients with DR.

Discrepancy between wrist-actigraph and polysomnographic measures of sleep in patients with stable heart failure and a novel approach to evaluating discrepancy

Wrist-actigraphy is often used to measure sleep characteristics in a variety of populations, but discrepancies between actigraphic and polysomnographic measures have been noted in populations experiencing poor sleep quality. The purpose of this study is to examine the discrepancy between these measures and risk factors for discrepancy in people with heart failure using a novel index. We used sleep measures simultaneously recorded by actigraphy and polysomnography, and clinical data from a cross-sectional study of 155 patients with heart failure (age = 60.5 [16.1] years; 65.2% male) recruited from evidence-based heart failure disease management programmes. The discrepancy and consistency between the two measures were evaluated using Bland-Altman plots, intra-class correlations and a newly developed index that represents activity counts in wake episodes. Overall, participants had short total sleep time (327.7 [95.9] min) and poor sleep efficiency (71.3 [16.0]%) on polysomnography. The discrepancies between sleep measures were small in patients less than 60 years old, and there was excellent consistency (intra-class correlation = 0.81) compared with older patients who had poorer consistency (intra-class correlation = 0.53) on total sleep time. Higher daytime motor activity, poor sleep quality and more severe insomnia were associated with smaller discrepancies in older, but not younger, patients, and associations were more sensitively detected by the new index. These findings suggest the importance of aging, disability and co-morbidity that may influence motor activity from which sleep estimates are scored with actigraphy. The new index may be useful in identifying factors associated with the correspondence between actigraphy and polysomnography.

A survey on sleep assessment methods

Purpose

A literature review is presented that aims to summarize and compare current methods to evaluate sleep.

Methods

Current sleep assessment methods have been classified according to different criteria; e.g., objective (polysomnography, actigraphy…) vs. subjective (sleep questionnaires, diaries…), contact vs. contactless devices, and need for medical assistance vs. self-assessment. A comparison of validation studies is carried out for each method, identifying their sensitivity and specificity reported in the literature. Finally, the state of the market has also been reviewed with respect to customers’ opinions about current sleep apps.

Results

A taxonomy that classifies the sleep detection methods. A description of each method that includes the tendencies of their underlying technologies analyzed in accordance with the literature. A comparison in terms of precision of existing validation studies and reports.

Discussion

In order of accuracy, sleep detection methods may be arranged as follows:

Questionnaire < Sleep diary < Contactless devices < Contact devices < Polysomnography

A literature review suggests that current subjective methods present a sensitivity between 73% and 97.7%, while their specificity ranges in the interval 50%–96%. Objective methods such as actigraphy present a sensibility higher than 90%. However, their specificity is low compared to their sensitivity, being one of the limitations of such technology. Moreover, there are other factors, such as the patient’s perception of her or his sleep, that can be provided only by subjective methods. Therefore, sleep detection methods should be combined to produce a synergy between objective and subjective methods. The review of the market indicates the most valued sleep apps, but it also identifies problems and gaps, e.g., many hardware devices have not been validated and (especially software apps) should be studied before their clinical use.

Subjective and objective sleep discrepancy in symptomatic bipolar disorder compared to healthy controls

BACKGROUND

Bipolar disorder (BD) is associated with sleep misperception. The objective of this study was to investigate the correlation between subjective and objective measures of sleep in persons with symptomatic bipolar disorder (BDS) compared to healthy controls (HC).

METHODS

We studied 24 BDS and 30 HC subjects similar in age, race and sex. Subjective sleep was measured with Pittsburgh Sleep Quality Index (PSQI) and objective sleep with 7-days of actigraphy. Absolute discrepancy variables were calculated by subtracting objective sleep latency (SL) and total sleep time (TST) on actigraphy from their respective subjective estimates from PSQI. Mood symptoms were measured with Young Mania Rating Scale and Hamilton Depression Rating Scale.

RESULTS

In the BDS group, subjective TST did not significantly correlate with objective TST, while it correlated in the HC group. The BDS group had significantly higher absolute discrepancy between subjective and objective SL and TST compared to the HC group. Multivariable regression analysis showed that severity of depression was associated with greater absolute discrepancy between subjective and objective TST within the BDS group.

LIMITATIONS

Subjects are from a tertiary care center and were on medications for treatment of BD symptoms.

CONCLUSION

There is low correlation between subjective and objective TST in BDS subjects and more severe depressive symptoms are associated with greater absolute discrepancy in TST. Objective rather than subjective measures of sleep, such as actigraphy, may be needed to evaluate sleep in BD subjects. Cognitive-behavioral interventions to address sleep misperception and associated depressed mood may be indicated in BD.

Calibrating actigraphy to improve sleep efficiency estimates

Actigraphy (ACT) can enhance treatment for insomnia by providing objective estimates of sleep efficiency; however, only two studies have assessed the accuracy of actigraphy-based estimates of sleep efficiency (ACT-SE) in sleep-disordered samples studied at home. Both found poor correspondence with polysomnography-based estimates (PSG-SE). The current study tested that concordance in a third sample and piloted a method for improving ACT-SE. Participants in one of four diagnostic categories (panic disorder, post-traumatic stress disorder, comorbid post-traumatic stress and panic disorder and controls without sleep complaints) underwent in-home recording of sleep using concurrent ambulatory PSG and actigraphy. Precisely synchronized PSG and ACT recordings were obtained from 41 participants. Sleep efficiency was scored independently using conventional methods, and ACT-SE/PSG-SE concordance examined. Next, ACT data recorded initially at 0.5 Hz were resampled to 30-s epochs and rescaled on a per-participant basis to yield optimized concordance between PSG- and ACT-based sleep efficiency estimates. Using standard scoring of ACT, the correlation between ACT-SE and PSG-SE across participants was statistically significant (r = 0.35, P < 0.025), although ACT-SE failed to replicate a main effect of diagnosis. Individualized calibration of ACT against a night of PSG yielded a significantly higher correlation between ACT-SE and PSG-SE (r = 0.65, P < 0.001; z = 1.692, P = 0.0452, one-tailed) and a significant main effect of diagnosis that was highly correspondent with the effect on PSG-SE. ACT-based estimates of sleep efficiency in sleep-disordered patients tested at home can be improved significantly by calibration against a single night of concurrent PSG.

Assessment for the possibility of a first night effect for wrist actigraphy in adolescents

OBJECTIVES

Evidence of a 'first night effect' has been documented for polysomnography. The possibility of this has not been previously assessed in wrist actigraphy, yet may have important implications for the study design of future sleep research. We sought to examine potential evidence of a 'first night effect' for wrist actigraphy in adolescents across weekdays and weekend nights for multiple sleep outcomes.

DESIGN

3-year prospective cohort study (Midlands Adolescent Schools Sleep Education Study).

SETTING

8 secondary schools in the Midlands region of the UK.

PARTICIPANTS

Adolescents (aged 11-13 years at baseline) were recruited to the study and were requested to wear a wrist actigraph for 7 consecutive days/nights at baseline and then annually for 2 years during the second term of the academic year.

PRIMARY OUTCOME MEASURES

We compared multiple sleep outcomes (total sleep time, wake after sleep onset, sleep efficiency, sleep onset latency, number of awakenings, length of awakenings, sleep onset time) when the device was worn on a weekday and weekend and compared these to other nights to identify possible evidence of a 'first night effect' for wrist actigraphy.

RESULTS

No significant differences were found between any sleep outcomes when the first night of wrist actigraphy was on a weekday compared with other weekdays. When the first night was measured on a weekend (Friday), average total sleep time was significantly greater (486±5 min) compared with the second night (Saturday; 469±6 min), p=0.01.

CONCLUSIONS

We found no evidence to support a 'first night effect' for wrist actigraphy in our adolescent sample. The first night of actigraphy data should not be disregarded in future studies that deploy this technique to measure sleep over prolonged time periods.