Karine Scheuermaier

SF-36: evaluation of quality of life in severe and mild insomniacs compared with good sleepers.

Objective Despite many studies, the impact of chronic insomnia on daytime functioning is not well understood. The aim of our study was to detect this impact by evaluating quality of life (QoL) using a validated instrument, the 36-item Short Form Health Survey of the Medical Outcomes Study (SF-36), in three matched groups of severe insomniacs, mild insomniacs, and good sleepers selected from the general population. Methods Three matched groups of 240 severe insomniacs, 422 mild insomniacs, and 391 good sleepers were recruited from the general French population after eliminating those with DSM-IV criteria for anxiety or depression. All subjects were asked to complete the SF-36. Scores for each QoL dimension were calculated and compared statistically among the three groups. Results Severe insomniacs had lower QoL scores in eight dimensions of the SF-36 than mild insomniacs and good sleepers. Mild insomniacs had lower scores in the same eight dimensions when compared with good sleepers. No dimension was significantly more altered than the other. Conclusions The mental health status and role of emotional QoL dimensions were worse in severe and mild insomniacs than in good sleepers. This result held even though we screened for psychiatric diseases, which shows a clear interrelation between insomnia and emotional state. General health status was also worse in severe and mild insomniacs than in good sleepers. However, we could conclude only that insomnia was related to a worse health status and not whether it was a cause or consequence of this worse health status. Finally, the degradation of QoL scores was correlated with the severity of insomnia.

Light exposure patterns in healthy older and young adults

Aging is associated with an earlier timing of circadian rhythms and a shorter phase angle between wake time and the timing of melatonin secretion or the core body temperature nadir. Light has a phase-dependent effect on the circadian pacemaker, and modifications of habitual light exposure in older people could contribute to a change in the timing of circadian rhythms or in the phase angle of entrainment. In this study, we compare natural light exposure of community-dwelling older and young subjects studied at the same time of year, focusing on the pattern of light exposure across the waking day. We recorded light exposure data for 3 to 8 days from 22 older (aged 66.01 ± 5.83) and 22 young subjects (aged 23.41 ± 4.57), living at home on self-selected sleepwake schedules, and matched for time of year. All subjects were from New England (latitude 42.3° N to 43° N). We compared the percentage of the waking day spent by older and young subjects at 4 different light levels (from very dim to very bright). We compared hourly averaged light exposure data in each group according to clock time and with respect to each subject’s daily sleepwake times. Although both age groups spent more than half of their waking hours in dim or moderate room light intensity (<100 lux), we found that the older subjects spent a significantly greater percentage of their waking day in the brighter light levels (≥1000 lux); their hourly averaged light exposure levels were also significantly greater whether we examined the data with respect to absolute clock time, to wake time, or to bed time, and this was true across all seasons. We found that healthy older people were exposed to significantly higher levels of light throughout their waking day than young people. Differences in natural light exposure may contribute to the age-related phase advance of the circadian pacemaker and its later timing relative to the sleepwake cycle. This hypothesis should be explored further in carefully designed prospective studies.

Effects on subjective and objective alertness and sleep in response to evening light exposure in older subjects

Evening bright light exposure is reported to ameliorate daytime sleepiness and age-related sleep complaints, and also delays the timing of circadian rhythms. We tested whether evening light exposure given to older adults with sleep-wake complaints would delay the timing of their circadian rhythms with respect to their sleep timing, thereby reducing evening sleepiness and improving subsequent sleep quality. We examined the impact of evening light exposure from two different light sources on subjective alertness, EEG activity during wakefulness, and sleep stages. Ten healthy older adults with sleep complaints (mean age=63.3 years; 6F) participated in a 13-day study. After three baseline days, circadian phase was assessed. On the evening of days 5-8 the subjects were exposed for 2h to either polychromatic blue-enriched white light or standard white fluorescent light, and on the following day circadian phase was re-assessed. Subjects were allowed to leave the laboratory during all but the two days when the circadian phase assessment took place. Evening assessments of subjective alertness, and wake and sleep EEG data were analyzed. Subjective alertness and wake EEG activity in the alpha range (9.75-11.25 Hz) were significantly higher during light exposures when compared to the pre-light exposure evening (p<0.05). The light exposures produced circadian phase shifts and significantly prolonged latency to rapid eye-movement (REM) sleep for both light groups (p<0.05). The increase in wake EEG alpha activity during the light exposures was negatively correlated with REM sleep duration (p<0.05). Evening light exposure could benefit older adults with early evening sleepiness, without negatively impacting the subsequent sleep episode.

In vitro effects of thawing fresh-frozen plasma at various temperatures.

Thawing fresh-frozen plasma (FFP) in South Africa is uncontrolled because the plasma is issued frozen from the blood bank and thawing techniques and temperatures are at the discretion of the clinician. Following anecdotal reports of disseminated intravascular coagulation (DIC) developing in patients who received FFP thawed in an uncontrolled manner, the effects of various thawing temperatures on coagulation parameters were studied. Fifteen adult units of FFP were each divided into 4 satellite units by the South African Blood Transfusion Service before freezing at -25°C. These bags were then defrosted in a waterbath at 22°C, 37°C, 45°C and 60°C, respectively, and removed as soon as they had thawed. Samples were collected for measurement of International Normalized Ratio (INR), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and D-dimers. These tests were done according to standard operating procedures. FFP samples were also used in place of agonist in platelet aggregation studies to assess whether the FFP could induce platelet aggregation. Results were analyzed with the percentage similarity model. Using this method the percentage similarity (%sim) of each bag thawed at each temperature with the same donor’s bag thawed at 37°C was calculated. The mean, standard deviation, and percentage coefficient of variation of the percentage similarities were then derived. Data sets were also compared using the Wilcoxon test. The fibrinogen values remained stable at 22-45°C (%sim = 97-99%) while there was a significant decrease in fibrinogen levels at 60°C compared with 37°C (p<0.001,%sim = 75%). INR and PTT values were highest in the bags thawed at 60°C (%sim = 114% and 110%, respectively) with the difference between the INR levels at 60°C compared with 37°C showing statistical significance (p<0.05). D-dimers were high at all temperatures tested with widely ranging results at each temperature. The FFP did not induce platelet aggregation at any of the thawing temperatures. In summary, INR and PTT values increase at a thawing temperature of 60°C compared with 37°C. D-dimers are elevated in thawed FFP. Fibrinogen levels are markedly decreased in FFP thawed at 60°C compared with that thawed at 37°C. FFP should be thawed at 37°C in a strictly controlled environment.

The relationship between alertness and sleep in a population of 769 elderly insomniacs with and without treatment with zolpidem

The sleep and life rhythms of 769 insomniacs aged more than 65 years were recorded during a period of 3 months before and after a treatment with 5 mg or 10 mg zolpidem per day during 27 days. The patients were selected by general practitioners throughout France: all had been suffering from insomnia for more than 3 weeks and were included in the study whether they had or had not been treated for these sleep disturbances. The evaluation of sleep and life rhythms was made by both the practitioners and the patients during 3 months. A single course of 5 or 10 mg per day of zolpidem during 27 days seemed sufficient to improve sleep parameters and increase alertness in a large percentage of insomniacs, thus establishing a clear relationship between sleep and alertness in the elderly.

Reciprocal relationship between age-related sleep disruption and urological symptoms.

Nocturia is common in middle-aged and older patients, affecting 40–60% of people > 55 years old [1-3]. It is classically considered to be a urological disorder, whereby excess production of urine at night, or a reduced nocturnal bladder capacity, leads to an awakening to void. An alternative possibility is that sleep disruption, a common feature of aging [4-6], leads to a nocturnal awakening and a decision to void. To explore the associations between urinary symptoms, sleep disruption and daytime sleepiness, we conducted a survey in two groups of older adults: patients visiting our urology clinic and healthy adults volunteering for sleep or circadian rhythm studies in our research laboratory.

Improved cognitive morning performance in healthy older adults following blue-enriched light exposure on the previous evening

Objectives Exposure to light can have acute alerting and circadian phase‐shifting effects. This study investigated the effects of evening exposure to blue‐enriched polychromatic white (BEL) vs. polychromatic white light (WL) on sleep inertia dissipation the following morning in older adults. Methods Ten healthy older adults (average age = 63.3 yrs; 6F) participated in a 13‐day study comprising three baseline days, an initial circadian phase assessment, four days with 2‐h evening light exposures, a post light exposure circadian phase assessment and three recovery days. Participants were randomized to either BEL or WL of the same irradiance for the four evening light exposures. On the next mornings at 2, 12, 22 and 32 min after each wake time, the participants completed a 90‐s digit‐symbol substitution test (DSST) to assess working memory, and objective alertness was assessed using a wake EEG recording. DSST and power density from the wake EEG recordings were compared between the two groups. Results DSST performance improved with time awake (p < 0.0001) and across study days in both light exposure groups (p < 0.0001). There was no main effect of group, although we observed a significant day x group interaction (p = 0.0004), whereby participants exposed to BEL performed significantly better on the first two mornings after light exposures than participants in WL (post‐hoc, p < 0.05). On those days, the BEL group showed higher EEG activity in some of the frequency bins in the sigma and beta range (p < 0.05) on the wake EEG. Conclusion Exposure to blue‐enriched white light in the evening significantly improved DSST performance the following morning when compared to polychromatic white light. This was associated with a higher level of objective alertness on the wake EEG, but not with changes in sleep or circadian timing. HighlightsWe exposed healthy older adults to evening blue‐enriched vs. ordinary white light.Blue‐enriched light exposure improved working memory performance the next morning.This effect was not due to changes in circadian timing or sleep quality.This effect was not due to waking from REM vs. NREM.Blue‐enriched light exposure also increased objective alertness on the wake EEG the next morning.

Circadian Rhythm Disorders: Does Sex Matter?

There are sex-related differences in circadian rhythms with women having shorter intrinsic periods and earlier phase of both temperature and melatonin rhythms relative to men. Although still equivocal, women may also have different amplitudes of their temperature rhythms, but the extent of the difference appears to depend on menstrual cycle phase and age. These sex-related differences may be due to differences in output of the suprachiasmatic nucleus, which has sex steroid receptors, or due to differences downstream of the circadian pacemaker. Sex-related differences in the prevalence of circadian rhythm sleep disorders require further study although it appears that men and women are equally likely to experience advanced and delayed sleep phase syndrome. However, men are more than two times more likely than women to suffer from non-24-h sleep–wake syndrome. Limited evidence indicates that men and women adapt equally well physiologically to shift work but women show more symptoms of intolerance and greater sleep difficulties than men possibly because of social factors such as maternal responsibilities, which add to the workload and reduce time for sleep. There are special concerns for health-related consequences of shift work in women given that female shift workers are at increased risk for breast cancer, fertility problems, and preterm births compared with female nonshift workers.