J.H.M. Tulen

Disagreement between subjective and actigraphic measures of sleep duration in a population-based study of elderly persons

Sleep duration is an important concept in epidemiological studies. It characterizes a night’s sleep or a person’s sleep pattern, and is associated with numerous health outcomes. In most large studies, sleep duration is assessed with questionnaires or sleep diaries. As an alternative, actigraphy may be used, as it objectively measures sleep parameters and is feasible in large studies. However, actigraphy and sleep diaries may not measure exactly the same phenomenon. Our study aims to determine disagreement between actigraphic and diary estimates of sleep duration, and to investigate possible determinants of this disagreement. This investigation was embedded in the population‐based Rotterdam Study. The study population consisted of 969 community‐dwelling participants aged 57–97 years. Participants wore an actigraph and kept a sleep diary for, on average, six consecutive nights. Both measures were used to determine total sleep time (TST). In 34% of the participants, the estimated TST in the sleep diaries deviated more than 1 h from actigraphically measured TST. The level of disagreement between diary and actigraphic measures decreased with subjective and actigraphic measures of sleep quality, and increased with male gender, poor cognitive function and functional disability. Actigraphically measured poor sleep was often accompanied by longer subjective estimates of TST, whereas subjectively poor sleepers tended to report shorter TST in their diaries than was measured with actigraphy. We recommend, whenever possible, to use multiple measures of sleep duration, to perform analyses with both, and to examine the consistency of the results over assessment methods.

Fatigue in primary Sjögren’s syndrome

OBJECTIVE To assess fatigue in relation to depression, blood pressure, and plasma catecholamines in patients with primary Sjögren’s syndrome (SS), in comparison with healthy controls and patients with rheumatoid arthritis. METHODS For the assessment of fatigue the Multidimensional Fatigue Inventory (MFI) was used, a 20 item questionnaire, covering the following dimensions: general fatigue, physical fatigue, mental fatigue, reduced motivation, and reduced activity. Furthermore, the Zung depression scale was used to quantify aspects of depression. Forty nine female primary SS patients, 44 female patients with rheumatoid arthritis (RA), and 32 healthy women filled in both questionnaires. In addition, supine values of blood pressure and plasma catecholamines were measured in the patients with primary SS. RESULTS Primary SS patients were more fatigued compared with the healthy controls on all the five dimensions of the MFI. When the analyses were repeated using depression as a covariate, group differences disappeared for the dimensions of reduced motivation and mental fatigue. In the primary SS patients, significant positive correlations between depression and the dimensions of reduced motivation and mental fatigue were found. Comparing patients with primary SS with those with RA, using depression as covariate, no statistically significant differences were found between these groups. No relation between fatigue and blood pressure was found, but a negative correlation was observed between the general fatigue subscale of the MFI and plasma noradrenaline. CONCLUSION Patients with primary SS report more fatigue than healthy controls on all the dimensions of the MFI and when controlling for depression significant differences remain on the dimensions of general fatigue, physical fatigue, and reduced activity. The negative correlations between levels of noradrenaline and general fatigue in patients with primary SS may imply the involvement of the autonomic nervous system in chronic fatigue.

Quantification of physical activities by means of ambulatory accelerometry: a validation study.

The objective of the study was to assess the validity of an activity monitor (AM) within a psychophysiological study. The AM was based on four body-fixed accelerometers and discriminated postures, transitions, and dynamic activities. Three subjects participated in each of two 4-hr sessions. During each session, consisting of two protocols, ambulatory accelerometer and heart rate measurements were made. The output of the AM was compared with simultaneously recorded video tapes. An overall agreement between AM and video of 88 and 96% was found. The number of transitions and dynamic periods, and the duration of activities were well determined. Posture-related heart rate changes were demonstrated. A three-sensor configuration hardly influenced the validity scores. The AM appeared to be a valid instrument to quantify aspects of physical activity, and offers new possibilities for ambulatory psychophysiological research.

Actigraphic sleep duration and fragmentation are related to obesity in the elderly: the Rotterdam Study.

Objective:The epidemiological evidence for the association between sleep duration and obesity in the elderly is inconsistent and has not been investigated with objective measures. Furthermore, the role of sleep fragmentation in this relationship is unknown. Our aim was to investigate the association of sleep measures with body mass index (BMI) and obesity in a normal elderly population.Design:Cross-sectional study.Subjects:A total of 983 community-dwelling elderly (mean age 68.4±6.9 years, range, 57–97).Measurements:Weight and height were measured, and sleep duration and fragmentation were assessed with on average six nights of actigraphy.Results:A quadratic model adequately described the association between continuous measures of sleep duration and BMI. Actigraphic sleep duration had a significant U-shaped relationship with BMI (β of quadratic term=0.30, 95% confidence interval (CI): 0.08, 0.52). Both short sleepers (<5 h: OR, 2.76 (95% CI: 1.38, 5.49), 5 to <6 h: OR, 1.97 (95% CI: 1.26, 3.08)) and long sleepers (⩾8 h: OR, 2.93 (95% CI: 1.39, 6.16)) were more likely to be obese, compared to participants who slept 7 to <8 h. BMI increased with 0.59 kg m−2 per standard deviation of sleep fragmentation (95% CI: 0.34, 0.84). After adjustment for sleep fragmentation, the association between short sleep and obesity was no longer significant. Exclusion of participants with probable sleep apnea only marginally changed these associations. Self-reported habitual sleep duration was not associated with BMI or obesity.Conclusions:Sleep duration, as measured with actigraphy, had a U-shaped relationship with BMI and obesity in an elderly population. A highly fragmented sleep is associated with a higher BMI and a higher risk of obesity, and may explain why short sleep is related to obesity. To preclude bias that can be introduced by self-report measures of sleep duration, using multiple measures of sleep parameters is recommended in future research.

Characterization of stress reactions to the stroop color word test

Sympatho-adrenal activation induced by stress contributes to the development of pathological states such as hypertension and anxiety disorders. The Stroop Color Word Test (CWT) is evaluated as a test for the study of stress-induced sympathetic effects, on the basis of psychological, physiological and biochemical responses. The CWT induced increases in plasma and urinary adrenaline, heart rate, respiration rate, electrodermal activity, electromyography, feelings of anxiety, and decreased finger pulse amplitude.

Motor activity and autonomic cardiac functioning in major depressive disorder

BACKGROUND The daily pattern of motor activity and the autonomic cardiovascular regulation were studied in major depression to quantify changes in psychomotor function and autonomic cardiac functioning. Additionally, relationships between motor activity parameters, cardiovascular measures and specific clinical features were examined. METHODS Wrist-actigraphy was used to monitor 24-h motor activity for 67 unmedicated (unipolar) depressed inpatients and 64 control subjects. During supine rest, spectral analysis was applied to assess HR and SBP variability, a baroreflex sensitivity (BRS) index and the respiratory frequency, in addition to mean heart rate (HR) and blood pressure (BP) levels for the patient group and a second control group (N=51). RESULTS The patients showed a lower motor activity level and a reduced fragmentation of motor activity during wake, and a higher motor activity level and a decreased immobility during sleep. The mean HR and DBP level and the respiratory frequency were higher in the patient group than in the control group, but no differences in HR and SBP variability or BRS were found. Furthermore, motor activity parameters and cardiovascular measures of the patients were related to agitation and retardation and overall, patients with lower motor activity levels demonstrated lower SBP levels. CONCLUSIONS This study confirms that the 24-h pattern of motor activity is altered in unmedicated depressed inpatients, but limited evidence was found for an autonomic cardiac dysfunction. Within the patient group there were relationships between motor activity parameters, cardiovascular measures, and clinical features, but the underlying neurobiological pathways need to be further explored.

Sleep Duration and Hypertension Are Not Associated in the Elderly

Several large studies have shown that both short and long average sleep durations increase the risk of hypertension in adults. We investigated whether sleep duration is also associated with hypertension in the elderly. This cross-sectional study was conducted in 5058 participants of the population-based Rotterdam Study, aged 58 to 98 years. Blood pressure was measured at the research center. Hypertension was defined as a systolic blood pressure of ≥160 mm Hg and/or a diastolic blood pressure of ≥100 mm Hg or current use of antihypertensive medication. In all of the participants, sleep duration was assessed by self-report. In a subsample of 975 subjects, it was additionally measured with actigraphy, a validated method that infers wakefulness and sleep from the presence or absence of limb movement. After adjustment for age and gender and additionally for body mass index, smoking, depressive symptoms, sleep medication use, diabetes mellitus, myocardial infarction, and stroke, none of the odds ratios (varying from 0.54; 95% CI: 0.27 to 1.08; to 1.19; 95% CI: 0.89 to 1.58) reflected a significant association between sleep duration and hypertension, whether measured by self-report or actigraphy. This study strongly suggests that sleep duration is not associated with hypertension in the elderly.

Cardiovascular variability in major depressive disorder and effects of imipramine or mirtazapine (Org 3770).

Spectral analysis of fluctuations in heart rate (HR) and blood pressure (BP) was applied to assess sympathetic and parasympathetic cardiovascular control mechanisms in patients with unipolar affective disorder before and after treatment with imipramine (IMI) or mirtazapine (MIR). In a double-blind randomized study, 10 patients received treatment with IMI and 10 patients received treatment with MIR. Cardiovascular parameters were studied before and after 4 weeks of treatment: HR and BP (Finapres) were recorded continuously during supine rest (SR) and orthostatic challenge (OC; 60-degrees head-up tilting). During SR and OC, power spectra were calculated for HR and systolic BP. Spectral density was assessed for three frequency bands: low (0.02-0.06 Hz), mid (0.07-0.14 Hz), and high (0.15-0.50 Hz). Before treatment, the depressed patients (N = 20) differed from age-matched controls (N = 20) only in their response to OC: the depressed patients showed more suppression of HR variability (both mid- and high-frequency band fluctuations), indicating stronger vagal inhibition, and a reduced increase of BP variability (mid-frequency band fluctuations), indicating reduced sympathetic activation. After 4 weeks of treatment, patients treated with either antidepressant drug showed significant changes of HR (increase) and HR variability (decrease) during SR and OC; the suppression of mid- and high-frequency fluctuations of HR was larger for IMI than for MIR. The increase in HR and decrease in HR variability may be attributed to the anticholinergic properties of IMI (strong) and MIR (weak), resulting in cardiac vagal inhibition. Whereas MIR had no effect on BP or BP variability, IMI specifically reduced mid-frequency band fluctuations of BP as the result of a suppression of central sympathetic activity. Our data confirm and extend previous observations on the presence of autonomic dysfunctions in unmedicated depressed patients: spectral analysis of HR and BP fluctuations suggested that both parasympathetic and sympathetic mechanisms are involved, specifically during OC. The preexisting autonomic cardiovascular dysfunctions were not normalized by antidepressant drugs. In fact, some of the components of the cardiovascular autonomic dysfunction were further aggravated, depending on the pharmacologic profile of the drug under investigation.

Preoperative and operative predictors of delirium after cardiac surgery in elderly patients

OBJECTIVES Delirium is a common complication in elderly patients after cardiac surgery and is associated with adverse outcomes including prolonged hospital stay and increased mortality. Therefore, prevention or early detection of delirium is indicated. Our objective was to identify preoperative and operative characteristics that could predict delirium after cardiac surgery in elderly patients. METHODS We conducted a prospective cohort study in which we analysed 201 patients of 70 years and older who underwent cardiac surgery, for developing a delirium. Patients were assessed daily using the Confusion Assessment Method-Intensive Care Unit. RESULTS Sixty-three patients (31%) developed a delirium after cardiac surgery. The Mini-Mental State Examination (MMSE) score prior to surgery was lower in the delirious patients when compared with the non-delirious patients (27 vs. 28, P = 0.026), creatinine level was higher (98 vs. 88 μmol/l, P = 0.003) and extracorporeal circulation (ECC) time was longer (145 vs. 113 min, P < 0.001). Mortality during the first 30 days after surgery in patients with delirium was significantly higher than that in the non-delirious patients (14 vs. 0%, P < 0.001). CONCLUSIONS Low MMSE score and high creatinine level prior to surgery as well as increased ECC time are important independent predictors of delirium. In addition, delirium is an important predictor of 30-day mortality. Patients with a substantial risk for delirium should be candidates for interventions to reduce postoperative delirium and to potentially improve overall surgical outcomes.

Autonomic reactivity in clinically referred children attention-deficit/hyperactivity disorder versus anxiety disorder

This study examined whether children with attention-deficit/hyperactivity disorder (ADHD) have lower autonomic nervous system (ANS) activity and show less stress reactivity than children with an anxiety disorder. It also explored whether such a difference was accounted for by comorbid oppositional defiant disorder (ODD) or conduct disorder (CD) in some of the ADHD children. Forty-three referred children performed a stress task, during which skin conductance (SCL) and heart rate (HR) levels were measured. Results showed that the ADHD group had similar SCL responses as the anxiety disorder group, but showed less HR reactivity immediately after the stress task. The ADHD with ODD/CD group had a slightly higher HR level than the pure ADHD group, but showed similar SCL and HR reactivity and recovery. It was concluded that ADHD children have less HR reactivity immediately after stress than children with an anxiety disorder, which was not accounted for by comorbid ODD/CD symptoms, and which may be related to a stronger parasympathetic than sympathetic activation.