Pain in your day? Get sleep treatment anyway! The role of pain in insomnia treatment efficacy in women veterans.

Insomnia and pain disorders are among the most common conditions affecting United States adults and veterans, and their comorbidity can cause detrimental effects to quality of life among other factors. Cognitive behavioural therapy for insomnia and related behavioural therapies are recommended treatments for insomnia, but chronic pain may hinder treatment benefit. Prior research has not addressed how pain impacts the effects of behavioural insomnia treatment in United States women veterans. Using data from a comparative effectiveness clinical trial of two insomnia behavioural treatments (both including sleep restriction, stimulus control, and sleep hygiene education), we examined the impact of pain severity and pain interference on sleep improvements from baseline to post-treatment and 3-month follow-up. We found no significant moderation effects of pain severity or interference in the relationship between treatment phase and sleep outcomes. Findings highlight opportunities for using behavioural sleep interventions in patients, particularly women veterans, with comorbid pain and insomnia, and highlight areas for future research.

Comparing actigraphy and diary to measure daily and average sleep in firefighters: a Bland-Altman analysis.

STUDY OBJECTIVES: This study sought to examine the relationship between actigraphy and the Consensus Sleep Diary to contribute information on their concurrent validity in a sample of career firefighters. METHODS: Sixty firefighters were recruited from a large, urban fire department in the southwest United States that utilizes a fire-based emergency medical services system and a 5/6 shift schedule. A total of 329 differences were recorded during participants' 6-day between-shift recovery period. Data was collected utilizing the two most common forms of sleep analysis in an outpatient setting, wrist actigraphy (Actiwatch-2) and the Consensus Sleep Diary. Nine major sleep indices were computed: wake time after sleep onset, total sleep time, sleep onset latency, sleep offset, in-bed time, lights-off time, out-of-bed time, wake time, and sleep efficiency. RESULTS: Firefighters overestimated sleep efficiency and underestimated wake after sleep onset by values that were greater than the American Academy of Sleep Medicine a priori clinical significance thresholds. All indices showed very broad limits of agreement. For example, the 95% confidence interval for diary and actigraphic total sleep time estimates fell within a 4.7-hour range. CONCLUSIONS: Firefighters receiving recovery sleep between tours demonstrated significantly large disagreements between their daily self-reported sleep and measured actigraphic sleep. Sleep findings from actigraphic and Consensus Sleep Diary sleep assessments in this population should be interpreted cautiously until each method is compared against other reliable sleep analysis methods. Currently it is unclear if clinicians are using properly validated tools when diagnosing shift work disorder or other sleep disorders in firefighters. CITATION: Marmis R, McGoldrick-Ruth L, Kelly MR, Haynes PL. Comparing actigraphy and diary to measure daily and average sleep in firefighters: a Bland-Altman analysis. J Clin Sleep Med. 2024;20(4):497-503.

Values Expressed by Women Veterans Receiving Treatment for Chronic Insomnia Disorder.

OBJECTIVES: Insomnia may contribute to fewer value-consistent choices and less engagement in meaningful life activities. We sought to identify values commonly expressed by women veterans engaged in a trial testing psychological treatment of insomnia disorder. METHODS: Seventy-four women veterans (mean age = 48.3 [±13] years), meeting DSM-5 diagnostic criteria for insomnia disorder received an acceptance-based behavioral treatment for insomnia. In the first session, participants responded to questions regarding personal values and the impact of insomnia on those values. Responses were categorized into values domains informed by the Bull's Eye Values survey (level 1 categories) and the Valued Living Questionnaire (level 2 categories). RESULTS: Raters reached 100% agreement after independent coding and adjudication. Level 1 value categories in frequency order were: relationships (n = 68), personal care/health (n = 51), work/education (n = 46), pets (n = 12), and leisure (n = 5). The most frequently reported level 2 value categories were: family (other than marriage/parenting; n = 50), parenting (n = 31), work (n = 31), physical health (n = 30), and spirituality (n = 19). The level 1 value categories impacted by insomnia in frequency order were: personal care/health (n = 65), relationships (n = 58), work/education (n = 46), pets (n = 12), and leisure (n = 5). CONCLUSIONS: Women veterans undergoing insomnia treatment highly value relationships and personal care/health, which should be considered patient-centered outcomes of insomnia treatments. CLINICAL TRIALS REGISTRATION: NCT02076165.

Novel treatment based on acceptance and commitment therapy versus cognitive behavioral therapy for insomnia: A randomized comparative effectiveness trial in women veterans.

OBJECTIVE: This randomized comparative effectiveness trial evaluated a novel insomnia treatment using acceptance and commitment therapy (ACT) among women veterans. Participants received either the acceptance and the behavioral changes to treat insomnia (ABC-I) or cognitive behavioral therapy for insomnia (CBT-I). The primary objectives were to determine whether ABC-I was noninferior to CBT-I in improving sleep and to test whether ABC-I resulted in higher treatment completion and adherence versus CBT-I. METHOD: One hundred forty-nine women veterans with insomnia disorder (Mage = 48.0 years) received ABC-I or CBT-I. The main sleep outcomes were Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), and sleep efficiency (SE) by actigraphy (objective) and sleep diary (subjective). Measures were collected at baseline, immediate posttreatment, and 3-month posttreatment follow-up. Treatment completion and adherence were assessed during the interventions. RESULTS: Both interventions improved all sleep outcomes from baseline to immediate posttreatment and 3-month posttreatment follow-up. At immediate posttreatment, ABC-I was statically noninferior for sleep diary SE and objective SE, but noninferiority was not statistically confirmed for ISI or PSQI total scores. At 3-month posttreatment follow-up, ABC-I was noninferior for all four of the key outcome variables. There was not a statistically significant difference between the number of participants who discontinued CBT-I (11%) versus ABC-I (18%; p = .248) before completing treatment. ABC-I was superior to CBT-I for some adherence metrics. CONCLUSIONS: Overall, ABC-I was similar in effectiveness compared to CBT-I for the treatment of insomnia and may improve adherence to some behavioral elements of treatment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Insomnia severity predicts depression, anxiety, and posttraumatic stress disorder in veterans with spinal cord injury or disease: a cross-sectional observational study.

STUDY OBJECTIVES: To assess the association of insomnia symptoms and psychiatric symptoms in patients with spinal cord injury or disease (SCI/D). METHODS: In this cross-sectional observational study, veterans with SCI/D (n = 72; mean = 59.85 ± 10.4 years; 92% male) completed baseline measures, including the Insomnia Severity Index (ISI) during the baseline phase of a clinical trial on treatment of sleep disorders in veterans with SCI/D. Depression severity was measured by the Patient Health Questionnaire (PHQ-9; sleep items excluded), anxiety severity was measured by the Generalized Anxiety Disorder screener (GAD-7), and probable posttraumatic stress disorder (PTSD) was measured by the Primary Care PTSD screener. Blocked regression was used to evaluate the impact of insomnia symptoms (ISI) on mental health measures after accounting for demographics and level of spinal cord injury/disease. RESULTS: On average, participants scored in the mild range for depression (PHQ-9 = 7.4 ± 5.9) and anxiety severity (GAD-7 = 6.1 ± 6.1). In total, 36.1% (n = 26) screened positive for probable PTSD. ISI explained 19% of the variance in PHQ-9 and 20% of the variance in GAD-7 (P < .001) over and above demographics and SCI/D level of injury/disease. Odds of probable PTSD were increased 1.22-fold for each 1 unit increase in ISI (P = .001) after accounting for demographics and level of injury/disease. CONCLUSIONS: In veterans with SCI/D, insomnia severity was linked to depression and anxiety symptom severity and risk of PTSD. Study results warrant further research to evaluate the impact of insomnia treatment on depression, anxiety, and PTSD in patients with SCI/D. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Treatment of Sleep-disordered Breathing in Patients With SCI; URL: https://clinicaltrials.gov/ct2/show/NCT02830074; Identifier: NCT02830074. CITATION: Kelly MR, Zeineddine S, Mitchell MN, et al. Insomnia severity predicts depression, anxiety, and posttraumatic stress disorder in veterans with spinal cord injury or disease: a cross-sectional observational study. J Clin Sleep Med. 2023;19(4):695-701.

Identifying gaps in clinical evaluation and treatment of sleep-disordered breathing in women veterans.

PURPOSE: Sleep-disordered breathing (SDB) is a common sleep disorder in veterans; however, limited research exists in women veterans. We sought to estimate patterns of care in terms of evaluation, diagnosis, and treatment among women veterans with factors associated with elevated SDB risk. METHODS: Within one VA healthcare system, women identified through electronic health record data as having one or more factors (e.g., age >50 years, hypertension) associated with SDB, completed telephone screening in preparation for an SDB treatment study and answered questions about prior care related to SDB diagnosis and treatment. RESULTS: Of 319 women, 111 (35%) reported having completed a diagnostic sleep study in the past, of whom 48 (43%) were diagnosed with SDB. Women who completed a diagnostic study were more likely to have hypertension or obesity. Those who were diagnosed with SDB based on the sleep study were more likely to have hypertension, diabetes, or be ≥50 years old. Of the 40 women who received treatment, 37 (93%) received positive airway pressure therapy. Only 9 (24%) had used positive airway pressure therapy in the prior week. Few women received other treatments such as oral appliances or surgery. CONCLUSIONS: Findings support the need for increased attention to identification and management of SDB in women veterans, especially those with conditions associated with elevated SDB risk.

Endogenous Diurnal Patterns of Adrenal and Gonadal Hormones During a 24-Hour Constant Routine After Simulated Shift Work.

Context: Night-shift work causes circadian misalignment, predicts the development of metabolic diseases, and complicates the interpretation of hormone measurements. Objective: To investigate endogenous circadian rhythms, dissociated from behavioral and environmental confounds, in adrenal and gonadal steroids after simulated shift work. Methods: Fourteen healthy adults (ages 25.8 ± 3.2 years) were randomized to 3 days of night or day (control) shift work followed by a constant routine protocol designed to experimentally unveil rhythms driven endogenously by the central circadian pacemaker. Blood was sampled every 3 hours for 24 hours during the constant routine to concurrently obtain 16 Δ4 steroid profiles by mass spectrometry. Cosinor analyses of these profiles provided mesor (mean abundance), amplitude (oscillation magnitude), and acrophase (peak timing). Results: Night-shift work marginally increased cortisol by 1 µg/dL (P = 0.039), and inactive/weak derivatives cortisone (P = 0.003) and 18-hydroxycortisol (P < 0.001), but did not alter the mesor of potent androgens testosterone and 11-ketotestosterone. Adrenal-derived steroids, including 11-ketotestosterone (P < 0.01), showed robust circadian rhythmicity after either day- or night-shift work. In contrast, testosterone and progesterone showed no circadian pattern after both shift work conditions. Night-shift work did not alter the amplitude or acrophase of any of the steroid profiles. Conclusion: Experimental circadian misalignment had minimal effects on steroidogenesis. Adrenal steroids, but not gonadal hormones, showed endogenous circadian regulation robust to prior shift schedule. This dichotomy may predispose night-shift workers to metabolic ill health. Furthermore, adrenal steroids, including cortisol and the main adrenal androgen 11-ketostosterone, should always be evaluated during the biological morning whereas assessment of gonadal steroids, particularly testosterone, is dependent on the shift-work schedule.

Change in Dysfunctional Sleep-Related Beliefs is Associated with Changes in Sleep and Other Health Outcomes Among Older Veterans With Insomnia: Findings From a Randomized Controlled Trial.

BACKGROUND: Cognitive behavioral therapy for insomnia (CBTI) targets changing dysfunctional sleep-related beliefs. The impact of these changes on daytime functioning in older adults is unknown. PURPOSE: We examined whether changes in sleep-related beliefs from pre- to post-CBTI predicted changes in sleep and other outcomes in older adults. METHOD: Data included 144 older veterans with insomnia from a randomized controlled trial testing CBTI. Sleep-related beliefs were assessed with the Dysfunctional Beliefs and Attitudes about Sleep-16 (DBAS-16, subscales: Consequences, Worry/Helplessness, Sleep Expectations, Medication). Outcomes included sleep diary variables, actigraphy-measured sleep efficiency, Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), Flinders Fatigue Scale (FFS), Patient Health Questionnaire-9, and health-related quality of life. Analyses compared slope of change in DBAS subscales from baseline to posttreatment between CBTI and control, and assessed the relationship between DBAS change and the slope of change in outcomes from baseline to 6 months. RESULTS: Compared to controls, the CBTI group demonstrated stronger associations between improvement in DBAS-Consequences and subsequent improvement in PSQI, ISI, ESS, and FFS. The CBTI group also demonstrated stronger associations between improvement in DBAS-Worry/Helplessness and subsequent improvements in PSQI, ISI, and FFS; improvements in DBAS-Medication and PSQI; and improvements in DBAS-Sleep Expectations and wake after sleep onset (sleep diary) and FFS (all p < .05). CONCLUSIONS: Significant reduction in dysfunctional sleep-related beliefs following CBTI in older adults predicted improvement in several outcomes of sleep and daytime functioning. This suggests the importance of addressing sleep-related beliefs for sustained improvement with CBTI in older veterans. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00781963.

Actigraphy prior to Multiple Sleep Latency Test: nighttime total sleep time predicts sleep-onset latency.

STUDY OBJECTIVES: To evaluate the clinical utility of actigraphy as compared with sleep questionnaires prior to the Multiple Sleep Latency Test (MSLT) in a sleep disorders clinic population. METHODS: Twenty-eight clinically referred participants (mean age: 42.3 ± 18.8 years) completed the study protocol. On day 1, participants completed the following questionnaires: Epworth Sleepiness Scale (ESS), Insomnia Severity Index, Pittsburgh Sleep Quality Index (PSQI), Visual Analog Scale (affect, vigor), Patient Health Questionnaire, and Multidimensional Fatigue Symptom Inventory-Short Form. On days 1-8, participants wore an actigraph and completed a sleep diary to assess mean nighttime and mean daytime total sleep time and sleep efficiency or sleep percentage. On day 9, participants repeated the ESS and completed an MSLT. Correlations assessed mean MSLT sleep-onset latency (MSLT-SOL) vs actigraphy, sleep diary, and questionnaires. Chi-square analyses assessed abnormal MSLT-SOL (≤ 8 minutes) or daytime sleepiness (ESS ≥ 10) and referral question (ie, sleep-disordered breathing vs hypersomnolence disorder). RESULTS: Mean MSLT-SOL was correlated with nighttime total sleep time assessed via both actigraphy and diary, but not with questionnaires. Significant correlations emerged for ESS score on day 1 vs 9, actigraphy vs sleep diary mean nighttime total sleep time, and PSQI vs mean sleep diary sleep efficiency. There was no significant relationship between mean MSLT-SOL and referral question. CONCLUSIONS: Our finding that total sleep time measured by actigraphy was associated with MSLT-SOL suggests it is useful in informing the interpretation of MSLT findings; however, it does not appear to be a viable substitute for MSLT for the measurement of objective sleepiness in clinical settings. CITATION: Kelly MR, Zeidler MR, DeCruz S, et al. Actigraphy prior to Multiple Sleep Latency Test: nighttime total sleep time predicts sleep-onset latency. J Clin Sleep Med. 2022;18(1):161-170.

Benefits of Cognitive Behavioral Therapy for Insomnia for Women Veterans with and without Probable Post-Traumatic Stress Disorder.

OBJECTIVE: This study compared the benefits of cognitive-behavioral therapy for insomnia for sleep, mental health symptoms, and quality of life (QoL) in a sample of women veterans with and without probable post-traumatic stress disorder (PTSD) comorbid with insomnia disorder. METHODS: Seventy-three women veterans (30 with probable PTSD) received a manual-based 5-week cognitive-behavioral therapy for insomnia treatment as part of a behavioral sleep intervention study. Measures were completed at baseline, post-treatment, and 3-month follow-up. Sleep measures included the Insomnia Severity Index, Pittsburgh Sleep Quality Index, sleep efficiency measured by actigraphy, and sleep efficiency and total sleep time measured by sleep diary. Mental health measures included the PTSD Checklist-5, nightmares per week, Patient Health Questionnaire-9, and Generalized Anxiety Disorder-7 scale. QoL was measured with the Short Form-12. Linear mixed models compared changes over time across groups. Independent t tests examined PTSD symptom changes in women veterans with probable PTSD. RESULTS: Both groups demonstrated improvements across sleep (ps < .001-.040), mental health symptoms (ps < .001), and QoL measures (ps < .001). The probable PTSD group reported greater improvements in diary sleep efficiency (p = .046) and nightmares per week (p = .001) at post-treatment and in total sleep time (p = .029) and nightmares per week (p = .006) at follow-up. Most participants with probable PTSD experienced clinically significant reductions in PTSD symptoms at post-treatment (66.7%) and follow-up (60.0%). Significant reductions in intrusive and arousal/reactivity symptoms were maintained at follow-up. CONCLUSIONS: Cognitive-behavioral therapy for insomnia improves insomnia, mental health symptoms, and QoL among women veterans, with greater improvement in those with probable PTSD.

Recovery Sleep versus Emotion Regulation in Predicting Fire Service Shift Workers Stress, Fatigue and Irritability.

Objective/Background: Fire service shift workers are at risk of developing mental health difficulties related to sleep loss and emotion dysregulation. We aimed to clarify the relationship between off-shift recovery sleep and emotion regulation on stress, fatigue and irritability. Participants: A total of 61 fire service shift workers (e.g. firefighter, captain, engineer, paramedic) on a "5/6" shift. Methods: Following five 24-hour shifts, participants reported on emotion regulation as well as daily sleep, stress, fatigue and irritability during six consecutive off-shift recovery days. Mediation analyses examined (1) emotion regulation as a predictor and sleep as a mediator of stress, fatigue and irritability outcomes; and (2) sleep as a predictor and emotion regulation as a mediator of stress, fatigue and irritability outcomes. Results: Greater self-reported total sleep time predicted lower recovery stress, fatigue, and irritability. Greater subjective sleep efficiency predicted lower recovery stress and fatigue, but not irritability. No significant relationships emerged for objective sleep or emotion regulation variables predicting stress, fatigue or irritability. There were no significant findings with either emotion regulation or sleep variables included as mediators. Conclusions: These findings suggest that stress management programs for fire service shift workers may be most effective when targeting sleep efficiency and quantity rather than emotion regulation strategies in the off-shift recovery period.

Unemployed Individuals Reporting Hindrance Work Stress at Previous Job Have Increased Likelihood of Insomnia Disorder.

BACKGROUND: Workplace stress and unemployment are each associated with disturbances in sleep. However, a substantial gap exists in what we know about the type of workplace stress preceding job loss and the lasting effect workplace stressors may have on long-term health outcomes. We hypothesized that a specific type of workplace stress, hindrance stress, would be a stronger predictor of current insomnia disorder, compared to challenge stress. METHOD: Cross-sectional data were analyzed from 191 recently unemployed individuals participating in the ongoing Assessing Daily Patterns through occupational Transitions (ADAPT) study. Participants were administered the Cavanaugh et al. (J Appl Psychol. 85(1):65, 2000) self-reported work stress scale regarding their previous job and the Duke Sleep Interview (DSI-SD), a semi-structured interview assessing ICSD-3 insomnia disorder (chronic and acute). RESULTS: Results from logistic regression analyses indicated that hindrance work stress was associated with an increased likelihood of current overall, chronic, and acute insomnia disorder, when controlling for challenge stress and significant demographic factors. Challenge stress was associated with an increased likelihood of chronic insomnia disorder when controlling for hindrance stress and covariates. The association between challenge stress and acute insomnia differed as a function of sex. CONCLUSION: Hindrance work stressors were associated with increased odds of current insomnia disorder, even after employment ended. Across each of the tested models, hindrance stress had stronger effects on insomnia than challenge stress. These findings support and extend both the challenge-hindrance framework of work-related stress and the 3 P model of insomnia.

Insomnia Precipitating Events among Women Veterans: The Impact of Traumatic and Nontraumatic Events on Sleep and Mental Health Symptoms.

OBJECTIVE/BACKGROUND: The current study describes insomnia precipitating events reported by women Veterans and examines differences in sleep and psychological distress variables in those who endorsed traumatic, nontraumatic, or no insomnia precipitating events. PARTICIPANTS: Baseline data were collected from 347 women Veterans enrolled in a behavioral sleep intervention study (NCT02076165). METHODS: Participants completed self-report measures of insomnia symptoms, sleep quality, sleep efficiency (SE), nightmare frequency, and depression and posttraumatic stress disorder (PTSD) symptoms; SE was also assessed by wrist actigraphy. Participants responded to 2 open-ended questions assessing stressful life events and health changes that coincided with insomnia symptom onset. Responses were coded as traumatic, nontraumatic, and no events. Analyses of covariance examined the effect of insomnia precipitating event type on sleep and psychological symptom variables after controlling for sociodemographic factors. RESULTS: Overall, 25.80% of participants endorsed traumatic events, 65.80% endorsed only nontraumatic events, and 8.41% endorsed no events. Participants who endorsed traumatic events reported more severe insomnia (p = .003), PTSD (p = .001), and depression symptoms (p = .012), and poorer quality of sleep (p = .042) than participants who endorsed no events. Participants who endorsed traumatic events reported more severe PTSD symptoms (p = .004), a longer duration of sleep problems (p = .001), and poorer quality of sleep (p = .039) than participants who endorsed nontraumatic events. Participants who endorsed nontraumatic events reported more severe insomnia (p = .029) and PTSD (p = .049) symptoms than participants who endorsed no events. CONCLUSIONS: Trauma as a precipitant for insomnia may be related to higher symptom severity in women Veterans. Implications for treatment engagement and effectiveness remain unstudied.

Social rhythm regularity moderates the relationship between sleep disruption and depressive symptoms in veterans with post-traumatic stress disorder and major depressive disorder.

Approximately 50% to 80% of individuals with posttraumatic stress disorder (PTSD) also meet criteria for major depressive disorder (MDD). Sleep disturbance is a major concern in both PTSD and MDD, and is associated with poor treatment response, poor functional outcome and increased suicide risk. Social rhythm regularity, or the consistency of daily habitual behaviors, is theoretically linked to circadian rhythms and may be disturbed in both PTSD and MDD. The present study examined the relationship between social rhythm regularity, sleep disruption and MDD and PTSD symptoms in a sample of veterans with comorbid PTSD and MDD. Baseline data were obtained from 56 male veterans who met DSM-IV criteria for PTSD and MDD. Veterans completed the Social Rhythm Metric (SRM), a self-report questionnaire that assesses the regularity of routines by determining how regularly individuals completed 17 different types of activities. In a linear regression model, increased minutes awake after sleep onset (WASO) was a significant predictor of increased depression scores on the Hamilton Rating Scale for Depression (p < .05). SRM scores did not significantly predict depressive symptoms, however the interaction of WASO and SRM significantly predicted depressive symptoms (p = <.05), with significant relationships found at SRM scores less than 3.62. Neither minutes awake after sleep onset, SRM scores, nor their interaction was associated with PTSD symptom severity. Social and possibly circadian rhythm regularity may represent a risk or resilience factor for individuals with comorbid PTSD and MDD. Findings highlight the importance of exploring the interactions of sleep and social/circadian rhythms in depression in order to inform continued treatment development.

Delivering Cognitive Behavioral Therapy for Insomnia in Military Personnel and Veterans.

Insomnia is commonly reported by military populations, especially those with comorbid mental and physical health conditions. Co-occurring conditions result in an altered presentation of insomnia symptoms, and complicate provision of cognitive-behavioral therapy for insomnia (CBT-I), requiring supplementary assessment or modifications to traditional techniques. CBT-I has consistently demonstrated positive outcomes for active-duty service members and veterans, even in the context of significant comorbidities such as post-traumatic stress disorder, depression, sleep apnea, and chronic pain. Despite its promise, studies of CBT-I in some populations, including women and individuals with substance use disorders, remain relatively understudied in active-duty and veteran populations.

Evaluation of an automated single-channel sleep staging algorithm.

BACKGROUND: We previously published the performance evaluation of an automated electroencephalography (EEG)-based single-channel sleep-wake detection algorithm called Z-ALG used by the Zmachine(®) sleep monitoring system. The objective of this paper is to evaluate the performance of a new algorithm called Z-PLUS, which further differentiates sleep as detected by Z-ALG into Light Sleep, Deep Sleep, and Rapid Eye Movement (REM) Sleep, against laboratory polysomnography (PSG) using a consensus of expert visual scorers. METHODS: Single night, in-lab PSG recordings from 99 subjects (52F/47M, 18-60 years, median age 32.7 years), including both normal sleepers and those reporting a variety of sleep complaints consistent with chronic insomnia, sleep apnea, and restless leg syndrome, as well as those taking selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor antidepressant medications, previously evaluated using Z-ALG were re-examined using Z-PLUS. EEG data collected from electrodes placed at the differential-mastoids (A1-A2) were processed by Z-ALG to determine wake and sleep, then those epochs detected as sleep were further processed by Z-PLUS to differentiate into Light Sleep, Deep Sleep, and REM. EEG data were visually scored by multiple certified polysomnographic technologists according to the Rechtschaffen and Kales criterion, and then combined using a majority-voting rule to create a PSG Consensus score file for each of the 99 subjects. Z-PLUS output was compared to the PSG Consensus score files for both epoch-by-epoch (eg, sensitivity, specificity, and kappa) and sleep stage-related statistics (eg, Latency to Deep Sleep, Latency to REM, Total Deep Sleep, and Total REM). RESULTS: Sensitivities of Z-PLUS compared to the PSG Consensus were 0.84 for Light Sleep, 0.74 for Deep Sleep, and 0.72 for REM. Similarly, positive predictive values were 0.85 for Light Sleep, 0.78 for Deep Sleep, and 0.73 for REM. Overall, kappa agreement of 0.72 is indicative of substantial agreement. CONCLUSION: This study demonstrates that Z-PLUS can automatically assess sleep stage using a single A1-A2 EEG channel when compared to the sleep stage scoring by a consensus of polysomnographic technologists. Our findings suggest that Z-PLUS may be used in conjunction with Z-ALG for single-channel EEG-based sleep staging.

Performance evaluation of an automated single-channel sleep-wake detection algorithm.

BACKGROUND: A need exists, from both a clinical and a research standpoint, for objective sleep measurement systems that are both easy to use and can accurately assess sleep and wake. This study evaluates the output of an automated sleep-wake detection algorithm (Z-ALG) used in the Zmachine (a portable, single-channel, electroencephalographic [EEG] acquisition and analysis system) against laboratory polysomnography (PSG) using a consensus of expert visual scorers. METHODS: Overnight laboratory PSG studies from 99 subjects (52 females/47 males, 18-60 years, median age 32.7 years), including both normal sleepers and those with a variety of sleep disorders, were assessed. PSG data obtained from the differential mastoids (A1-A2) were assessed by Z-ALG, which determines sleep versus wake every 30 seconds using low-frequency, intermediate-frequency, and high-frequency and time domain EEG features. PSG data were independently scored by two to four certified PSG technologists, using standard Rechtschaffen and Kales guidelines, and these score files were combined on an epoch-by-epoch basis, using a majority voting rule, to generate a single score file per subject to compare against the Z-ALG output. Both epoch-by-epoch and standard sleep indices (eg, total sleep time, sleep efficiency, latency to persistent sleep, and wake after sleep onset) were compared between the Z-ALG output and the technologist consensus score files. RESULTS: Overall, the sensitivity and specificity for detecting sleep using the Z-ALG as compared to the technologist consensus are 95.5% and 92.5%, respectively, across all subjects, and the positive predictive value and the negative predictive value for detecting sleep are 98.0% and 84.2%, respectively. Overall κ agreement is 0.85 (approaching the level of agreement observed among sleep technologists). These results persist when the sleep disorder subgroups are analyzed separately. CONCLUSION: This study demonstrates that the Z-ALG automated sleep-wake detection algorithm, using the single A1-A2 EEG channel, has a level of accuracy that is similar to PSG technologists in the scoring of sleep and wake, thereby making it suitable for a variety of in-home monitoring applications, such as in conjunction with the Zmachine system.