Alistair W. MacLean

Sleep disturbance in cancer patients

Sleep difficulty is a prominent concern of cancer patients, yet there has been no large study of the prevalence and nature of sleep disturbance in cancer patients. This cross-sectional survey study examined: (a) the prevalence of reported sleep problems in patients attending six clinics at a regional cancer centre; (b) sleep problem prevalence in relation to cancer treatment; and (c) the nature of reported insomnia (type, duration, and associated factors). For three months, all patients attending clinics for breast, gastrointestinal, genitourinary, gynecologic, lung, and non-melanoma skin cancers were offered a brief sleep questionnaire. Response rate was 87%; the final sample size was 982. Mean age of respondents was 64.9 years (SD 12.5). The most prevalent problems were excessive fatigue (44% of patients), leg restlessness (41%). insomnia (31%), and excessive sleepiness (28%). Chi square tests showed significant variation among clinics in the prevalence of most sleep problems. The lung clinic had the highest or second-highest prevalence of problems. The breast clinic had a high prevalence of insomnia and fatigue. Recent cancer treatment was associated with excessive fatigue and hypersomnolence. Insomnia commonly involved multiple awakenings (76% of cases) and duration > or = 6 months (75% of cases). In 48% of cases, insomnia onset was reported to occur around the time of cancer diagnosis (falling within the period 6 months pre-diagnosis to 18 months post-diagnosis). The most frequently identified contributors to insomnia were thoughts, concerns, and pain/discomfort. In a multivariate logistic regression analysis, variables associated with increased odds of insomnia were fatigue, age (inverse relationship), leg restlessness, sedative/hypnotic use, low or variable mood, dreams, concerns, and recent cancer surgery. This study provides new information about sleep-related phenomena in cancer patients, information which will be useful in planning supportive care services for cancer patients.

How do prolonged wakefulness and alcohol compare in the decrements they produce on a simulated driving task

The effects of alcohol ingestion were compared with those of prolonged wakefulness on a simulated driving task. Eighteen healthy, male subjects aged between 19 and 35 years drove for 30 min on a simulated driving task at blood alcohol concentrations of 0.00, 0.05 and 0.08%. Subjective sleepiness was assessed before and after the driving task. Driving performance was measured in terms of the mean and standard deviation (S.D.) of lane position (tracking); the mean and S.D. of speed deviation (the difference between the actual speed and the posted speed limit); and the number of off-road occurrences. Ratings of sleepiness increased with increasing blood alcohol concentration, and were higher following the driving task. With increasing blood alcohol concentration, tracking variability, speed variability, and off-road events increased, while speed deviation decreased, the result of subjects driving faster. The results were compared with a previous study examining simulated driving performance during one night of prolonged wakefulness [Arnedt, J.T., MacLean A.W., 1996. Effects of sleep loss on urban and motorway driving stimulation performance. Presented at the Drive Alert... Arrive Alive International Forum, Washington DC], using an approach adopted by Dawson and Reid [Dawson, D., Reid, K., 1997. Fatigue, alcohol and performance impairment. Nature 388, 23]. For mean tracking, tracking variability, and speed variability 18.5 and 21 h of wakefulness produced changes of the same magnitude as 0.05 and 0.08% blood alcohol concentration, respectively. Alcohol consumption produced changes in speed deviation and off-road occurrences of greater magnitude than the corresponding levels of prolonged wakefulness. While limited to situations in which there is no other traffic present, the findings suggest that impairments in simulated driving are evident even at relatively modest blood alcohol levels, and that wakefulness prolonged by as little as 3 h can produce decrements in the ability to maintain speed and road position as serious as those found at the legal limits of alcohol consumption.

THE HAZARDS AND PREVENTION OF DRIVING WHILE SLEEPY

In the present paper the literature bearing on the association between sleepiness and driving is reviewed and the current state of prevention is discussed. Sleepiness may be a factor in about 20% of motor vehicle accidents and studies carried out in controlled environments suggest that the most common changes in driving performance attributable to sleepiness include increased variability of speed and lateral lane position. Higher-order functions including judgement and risk taking may also deteriorate. Moreover, prolonging wakefulness even by a few hours may produce deterioration in driving performance comparable to that seen in drivers with blood alcohol concentrations at levels deemed dangerous by legislation. The majority of prevention efforts to date have focussed on short-term solutions that only mask underlying sleepiness and it is suggested that more emphasis be directed toward primary prevention efforts such as educating drivers about the importance of getting sufficient sleep and avoiding circadian performance troughs. Finally, the important role that health professionals can play in the identification, treatment, and education of sleepy drivers is highlighted.

Psychometric evaluation of the Stanford Sleepiness Scale

SUMMARY  Two assumptions underlying the Stanford Sleepiness Scale (SSS) were evaluated: that the descriptors defining each level of the scale are equivalent ways of characterizing a particular level of sleepiness; and that sleepiness, thus measured, is an unidimensional construct. Twenty‐four True/False items were derived from the descriptors at each level of the SSS. This revised scale was administered to 340 undergraduates in a questionnaire which also included: the SSS; four visual analogue scales; items identifying the subjects age, sex, and circadian type; and the time of administration. Analyses of the responses indicated that endorsement of items on the revised scale was not consistent with the SSS level endorsed, indicating that the descriptors at each scale level are not equivalent. A principal components analysis revealed two components, tentatively identified as activation and sleepiness, accounting, respectively, for 24.2 and 20.6% of the variance. It was concluded that sleepiness is not an unidimensional construct. Further studies are necessary to elucidate the nature of its components.

The sleep of remitted bipolar depressives: comparison with sex and age-matched controls.

The sleep of 10 bipolar patients was recorded for five consecutive nights following their recovery from a depressive episode. In all respects except the number of arousals, their sleep did not differ reliably from that of 10 sex and age-matched control subjects. We conclude that sleep measures are unlikely to be useful as trait markers of a depressive diathesis in bipolar disorder.

Changes in paraspinal electromyographic spectral analysis with exercise: Two studies

It has been suggested, but not substantiated, that electromyographic (EMG) power spectrum (PS) analysis of the paraspinal muscles could be a useful method of evaluating low back pain treatment outcome. The use of PS analysis to measure paraspinal muscle adaptations was investigated in two studies: Study 1, involving previously sedentary healthy women who participated in a 12-week fitness class program, and Study 2, involving low back pain sufferers who participated in a 10-week back-care exercise program. All subjects underwent assessments of physical fitness (aerobic capacity, back strength, and flexibility) and EMG PS analysis of the multifidus and iliocostalis muscles (during a constant force contraction), before and after the experimental period. The results in both studies indicated that the EMG PS measures were sensitive to adaptive changes, with findings of (a) decreases in multifidus initial median frequency (IMF) and fatigue (FTG) of the fitness class participants and (b) an increase in multifidus IMF and decreases in multifidus and iliocostalis FTG of the back-care participants. The results are discussed with regard to possible links between spectral changes and alterations in muscle fiber characteristics and functioning, and the need for further research to substantiate such links.

Rapid eye movement latency and mood following a delay of bedtime in healthy subjects: do the effects mimic changes in depressive illness?

The phase advance hypothesis proposes that a phase advance of certain circadian rhythms (such as rapid eye movement (REM) sleep propensity) relative to the sleep‐wake cycle is implicated in the pathophysiology and pathogenesis of depression. In an earlier study, we reported that a 6‐h delay of sleep in normals produced REM changes that resembled the depressive pattern. Mood change was generally modest, although 2 of the 10 subjects became noticeably depressed. This study assessed the replicability of these results, and introduced a phase advance control condition. Predicted changes were observed in REM parameters. Modest but reliable mood change was confined to the first night of the phase delay, and was attributed to sleep loss. These results suggest that the effects of the phase shift were relatively benign, except in a minority of cases. Such individuals may have a susceptibility to depression that manifests itself under certain conducive physiological conditions.

Young drivers' perceptions of culpability of sleep-deprived versus drinking drivers.

INTRODUCTION Sleep-deprived driving can be as dangerous as alcohol-impaired driving, however, little is known about attitudes toward sleep-deprived drivers. This study examined the extent to which young drivers regard sleep-deprived compared to drinking drivers as culpable for a crash, and how their perceptions of driving while in these conditions differ. METHOD University student participants (N=295; M=20.4years, SD=1.3; 81% women) were randomly assigned to read one of five fatal motor-vehicle crash scenarios, which differed by aspects of the drivers condition. Culpability ratings for the drinking driver were higher than those for the sleep-deprived driver. RESULTS Qualitative findings revealed that driving while sleep-deprived was viewed as understandable, and driving after drinking was viewed as definitely wrong. The dangers of sleep-deprived driving remain under-recognized.

Alleviating sleep-related discontinuance symptoms associated with benzodiazepine withdrawal: A new approach

There is limited information on the time course of recovery of sleep architecture in patients withdrawn from benzodiazepines (BDZ). This study examined the effects of substituting a new class of hypnotic drugs, namely the cyclopyrrolones, for current BDZs in patients presenting with BDZ dependence. The results indicated a clear improvement in a variety of sleep parameters after commencing with a cyclopyrrolone (zopiclone). These changes remained to some extent after zopiclone was discontinued. Also, the absence of certain withdrawal effects (i.e. rebound insomnia) upon discontinuation of zopiclone allows for patients to be carried through a potentially difficult period after stopping BDZs, while expediting the eventual discontinuation of all hypnotic medication.

Sleep deprivation: outcome of controlled single case studies of depressed patients.

Six drug-free depressed patients, each of whom acted as their own control, were studied for eleven consecutive days during which they were twice deprived of sleep for either 36 or 40 hours. The sequence of events was baseline (3 days), SD, recovery (3 days), SD, recovery (3 days). Blind ratings of clinical state were made on the basis of four-hourly interviews (standardized for each case), which were videotaped; sleep was monitored by conventional electrophysiological methods. Sleep deprivation had a beneficial, but transient, effect on four of the six patients studied. Changes in sleep were unrelated to changes in clinical state.