Objectively assessed sleep and physical activity in depression subtypes and its mediating role in their association with cardiovascular risk factors.

The aims of this study were to investigate the associations of major depressive disorder (MDD) and its subtypes (atypical, melancholic, combined, unspecified) with actigraphy-derived measures of sleep, physical activity and circadian rhythms; and test the potentially mediating role of sleep, physical activity and circadian rhythms in the well-established associations of the atypical MDD subtype with Body Mass Index (BMI) and the metabolic syndrome (MeS). The sample consisted of 2317 participants recruited from an urban area, who underwent comprehensive somatic and psychiatric evaluations. MDD and its subtypes were assessed via semi-structured diagnostic interviews. Sleep, physical activity and circadian rhythms were measured using actigraphy. MDD and its subtypes were associated with several actigraphy-derived variables, including later sleep midpoint, low physical activity, low inter-daily stability and larger intra-individual variability of sleep duration and relative amplitude. Sleep midpoint and physical activity fulfilled criteria for partial mediation of the association between atypical MDD and BMI, and physical activity also for partial mediation of the association between atypical MDD and MeS. Our findings confirm associations of MDD and its atypical subtype with sleep and physical activity, which are likely to partially mediate the associations of atypical MDD with BMI and MeS, although most of these associations are not explained by sleep and activity variables. This highlights the need to consider atypical MDD, sleep and sedentary behavior as cardiovascular risk factors.

Actigraphic and nursing sleep log measures in moderate-to-severe traumatic brain injury: Identifying discrepancies in total sleep time.

BACKGROUND: Sleep disturbances are common in patients with traumatic brain injury (TBI). In an inpatient rehabilitation setting, clinicians often use information from sleep logs filled out by trained nurses to identify and treat sleep disturbances. However, there are limited data related to accuracy of sleep logs, and patient-reported sleep diaries are poor predictors of total sleep time, which raises concern about the accuracy of sleep logs filled out by a third party. OBJECTIVE: To examine the reliability of sleep logs for participants with TBI by comparing total sleep time determined by sleep logs versus actigraphy. DESIGN: Prospective, cross-sectional study. SETTING: Free-standing, academic inpatient rehabilitation facility. PARTICIPANTS: Thirty individuals (n = 30) participated in the study. Inclusion criteria were (1) diagnosis of moderate-to-severe TBI; (2) age ≥ 18 years at the time of TBI; and (3) participating in inpatient rehabilitation with no prior inpatient rehabilitation admissions. INTERVENTIONS: Actigraph monitoring using ActiGraph GT9X Link devices was initiated within 72 hours of admission and continued for 7 consecutive days. Sleep logs were concurrently filled out by trained nurses. MAIN OUTCOME MEASURES: Sleep parameter correspondence between actigraphy and sleep logs in moderate-to-severe TBI. RESULTS: Only 51.4% of participants' sleep logs and actigraph total sleep time measurements were within 1 hour of each other, and only 23.8% were within 30 minutes. On average, sleep logs overestimated actigraphy-determined total sleep time by 60 minutes compared to actigraphic measurement. CONCLUSIONS: For those with moderate-to-severe TBI undergoing inpatient rehabilitation, sleep logs are poor predictors of sleep time because they overestimate total sleep time compared to actigraphy. Therefore, clinicians should use caution when using sleep log data to make decisions regarding treatment for sleep disturbances in TBI.