Neil Stanley

A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality

Abstract Rationale: The effects of caffeine, especially caffeinated coffee, on human performance have been extensively studied. However, few studies have been naturalistic representations of how tea/coffee is normally consumed in terms of dose and time of consumption. Objectives: This study investigated the effects of day-long consumption of tea, coffee and water on cognitive and psychomotor performance, and sleep quality at night. Methods: Thirty healthy volunteers received equal volume drinks equivalent to either 1 or 2 cups of tea (containing 37.5 mg or 75 mg caffeine), or coffee (75 mg or 150 mg caffeine), or water, in a randomised five-way crossover design. Drinks were administered on four occasions during the day (0900, 1300, 1700 and 2300 hours). A psychometric battery consisting of critical flicker fusion (CFF), choice reaction time (CRT) and subjective sedation (LARS) tests, was administered pre-dose and at frequent time points post-dose. The Leeds Sleep Evaluation Questionnaire (LSEQ) was completed each morning and a wrist actigraph was worn for the duration of the study. Results: Caffeinated beverages maintained CFF threshold over the whole day (P<0.05), independent of caffeine dose or beverage type. During the acute phase of beverage ingestion, caffeine significantly sustained performance compared to water after the first beverage for CFF and subjective sedation (P<0.05), and after the second beverage for the Recognition component of the CRT task (P<0.05). Additionally, there were significant differences between tea and coffee at 75 mg caffeine after the first drink. Compared to coffee, tea produced a significant increase in CFF threshold between 30 and 90 min post-consumption (P<0.01). However, following the second beverage caffeinated coffee at 75 mg significantly improved reaction time (P<0.05), compared to tea at the same dose, for the Recognition component of the CRT task. Caffeinated beverages had a dose dependent negative effect on sleep onset (P<0.001), sleep time (P<0.001) and sleep quality (P<0.001). Conclusions: These results indicate that ingestion of caffeinated beverages may maintain aspects of cognitive and psychomotor performance throughout the day and evening when caffeinated beverages are administered repeatedly. This study also demonstrates that day-long tea consumption produces similar alerting effects to coffee, despite lower caffeine levels, but is less likely to disrupt sleep. Other differences between tea and coffee were more subtle, and require further investigation.

Job strain, work rumination, and sleep in school teachers

The objectives of this study were, firstly, to examine the association between job strain and sleep quality in a sample of primary and secondary school teachers and, secondly, to assess whether the relationship between job strain and sleep quality is mediated or moderated by an individuals inability to “switch-off ” from work-related issues during leisure time. School teachers (N = 143) completed an hourly record of their work-related thoughts over a workday evening between 5 p.m. and bedtime, and then rated their sleep quality the following morning. Individuals were classified as reporting high (n = 46) or low (n = 52) job strain using predetermined cut-off scores. Consistent with previous research, the results showed that both groups demonstrated a degree of unwinding and disengagement from work issues over the evening. However, compared to the low job strain group, the high job strain teachers took longer to unwind and ruminated more about work-related issues, over the whole evening, including bedtime. There was no difference in total sleep time between the groups, but high job strain individuals reported poorer sleep quality compared to low job strain individuals. With respect to the second objective, across the whole sample (N = 143), work rumination and job strain were significantly correlated with sleep quality, but work rumination was not found to mediate, or moderate the relationship between job strain and sleep quality. It was speculated that the initial low contribution of job strain to sleep quality (r = −.18) may have contributed to this null finding. The current findings may have implications for how we assess and manage sleep disturbance in stressed workers.

The physiology of sleep and the impact of ageing

Abstract Sleep is an essential part of life. It is not a passive state of unconsciousness, but rather a dynamic brain processthat is the result of the interaction between two largely independent basic mechanisms: the circadian rhythm and the homeostatic drive to sleep. Its exact role has yet to be elucidated but it is known that sleep plays an important role in the restoration of physical and mental functioning. Sleep can be described both quantitatively and qualitatively, subjectively and objectively. Recent research hasled to a substantially improved understanding of both normal and altered sleep patterns, and their impact on health. A large diversity of factors has been described that can either favourably or adversely influence sleep, including sleep deprivation, sleep fragmentation, medical conditions and external stimuli. Normal sleep patterns vary significantly across the life-course, with more disrupted and less efficient sleep seeming to occur in the elderly. Sleep disorders are frequent and diverse in their origin, and commonly result in excessive daytime somnolence, which can have a major impact on daytime performance and safety in the individual. Also, chronic sleep disturbance is associated with increased morbidity and mortality. It is thus important that the quality of sleep is maintained, and situations and conditions known to have a negative impact on sleep initiation and maintenance should be prevented or treated.

Allergy medication in Japanese volunteers: treatment effect of single doses on nocturnal sleep architecture and next day residual effects.

ABSTRACT Objectives: To evaluate the acute effects of two histamine H1-receptor antagonists on nocturnal sleep architecture and on next day cognitive function and psychomotor performance. Methods: This was a single-site, randomized, double-blind, 3-way crossover study, comparing the effects of a single dose of chlorpheniramine (6 mg), fexofenadine (120 mg) and placebo in 18 healthy (male and female) Japanese volunteers aged 20–55 years. Volunteers were resident for 3 days and each period was separated by a minimum 5‐day washout period. The three treatments were administered at 23.00 h. Overnight sleep was measured from 23.00 h to 07.00 h using polysomnography. Residual effects were studied at 07.00 h and 9.00 h the next morning, with the latency to sleep (sleep latency test) measured at 09.30 h. Results: Compared with placebo, chlorpheniramine increased the latencies to sleep onset and rapid eye movement (REM) sleep ( p ≤ 0.05 for both), and reduced the duration of REM sleep ( p ≤ 0.01), but this was not observed with fexofenadine. As far as residual effects the next morning were concerned there were decrements in performance with chlorpheniramine, but not with fexofenadine. Chlorpheniramine 6 mg impaired divided attention ( p < 0.001), vigilance ( p < 0.05), working memory ( p < 0.0001) and sensori-motor performance ( p < 0.01), and the latency to daytime sleep was reduced ( p < 0.0001). Six adverse events possibly related to study medication were reported during the study, three of which were related to placebo, two to fexofenadine and one to chlorpheniramine. Conclusion: These findings suggest that a single nocturnal dose of fexofenadine has advantages over the first-generation antihistamine chlorpheniramine, being free of disruption of night-time sleep and detrimental effects on cognitive performance the next day. It is likely that this advantage will remain with chronic ingestion, but this would need to be confirmed.

The effects of cigarette smoking on overnight performance.

Abstract Fifteen healthy smokers and 15 non-smokers were enrolled into this study investigating the effects of smoking on overnight performance. Subjects arrived at the test centre at 1930 hours and were assessed at baseline (2000 hours) and at 2200, 0000, 0200, 0400, 0600, and 0800 hours on a battery of tests (including Critical Flicker Fusion, CFF; Choice Reaction Time, CRT; Compensatory Tracking Task, CTT; Short Term Memory Task, STM; and the Line Analogue Rating Scale, LARS). Results showed that the performance of the smokers was more consistent with baseline measures than that of the non-smokers, which became more impaired throughout the night on a number of tasks [CFF (P < 0.005), Total Reaction Time (TRT, P < 0.05), CTT (P < 0.05) and the Reaction Time (RT) aspect of the CTT task (P < 0.0005)]. The Recognition Reaction Time (RRT) aspect of the CRT task showed that the performance of the non-smokers became more impaired from baseline (P < 0.005), while that of the smokers remained at baseline levels until 0400 hours, when it deteriorated to become comparable to that of the non-smoking controls. Subjective sedation ratings (LARS) resulted in comparable levels of impairment for both study groups (P < 0.00005). Findings from the STM task failed to reach significance. These data suggest that when performance is being measured overnight, smokers show little or no impairment, whilst the performance of non-smokers showed performance decrements.

Standard procedures for adults in accredited sleep medicine centres in Europe

The present paper describes standardized procedures within clinical sleep medicine. As such, it is a continuation of the previously published European guidelines for the accreditation of sleep medicine centres and European guidelines for the certification of professionals in sleep medicine, aimed at creating standards of practice in European sleep medicine. It is also part of a broader action plan of the European Sleep Research Society, including the process of accreditation of sleep medicine centres and certification of sleep medicine experts, as well as publishing the Catalogue of Knowledge and Skills for sleep medicine experts (physicians, non‐medical health care providers, nurses and technologists), which will be a basis for the development of relevant educational curricula. In the current paper, the standard operational procedures sleep medicine centres regarding the diagnostic and therapeutic management of patients evaluated at sleep medicine centres, accredited according to the European Guidelines, are based primarily on prevailing evidence‐based medicine principles. In addition, parts of the standard operational procedures are based on a formalized consensus procedure applied by a group of Sleep Medicine Experts from the European National Sleep Societies. The final recommendations for standard operational procedures are categorized either as ‘standard practice’, ‘procedure that could be useful’, ‘procedure that is not useful’ or ‘procedure with insufficient information available’. Standard operational procedures described here include both subjective and objective testing, as well as recommendations for follow‐up visits and for ensuring patients’ safety in sleep medicine. The overall goal of the actual standard operational procedures is to further develop excellence in the practice and quality assurance of sleep medicine in Europe.

Effects of fluoxetine and dothiepin on 24-hour activity in depressed patients

Psychomotor retardation is a recognised symptom of depressive illness, and improvement in psychomotor function is associated with the amelioration of the severity of depressive symptoms. Actigraphy permits behavioural activity to be continuously assessed, allowing changes in psychomotor activity to be monitored over time. A randomised, parallel-group, double-blind study was conducted in 14 general practice patients with a diagnosis of major depression. This pilot study was designed to investigate the utility of actigraphy in this patient population and to investigate possible differences between fluoxetine and dothiepin in their effects on 24-hour behavioural activity monitored for the first 10 days of treatment. Patients taking dothiepin (75 mg rising to 150 mg in the second week, nocte) were found to be significantly (p < 0.05) less active over the course of the day compared to those treated with fluoxetine (20 mg, mane). This lower level of behavioural activity in the dothiepin group was particularly noticeable in the early morning (06:00–08:00 h).

European guidelines for the certification of professionals in sleep medicine: report of the task force of the European Sleep Research Society

In recent years, sleep medicine has evolved into a full‐grown discipline, featuring a multidisciplinary approach to diagnosis and treatment of patients with sleep disorders. Sleep medicine cuts across the boundaries of different conventional disciplines and is therefore open to medical and non‐medical professionals with different specialty backgrounds. The aim of the current paper is to introduce a qualification for those professionals whose main occupation is to practice sleep medicine in the setting of a sleep medicine centre. The drafting of guidelines dealing with requirements for such qualification was entrusted to a task force by the European Sleep Research Society. The guidelines are the result of a progressive consensus procedure in which standards were defined for education, training, and evaluation. The final step along this pathway is a theoretical and practical examination, providing proof of proficiency in the field of sleep medicine. This paper describes the object of specific competences, the scope of sleep medicine, and the qualification procedures that pertain to three professional categories: medical specialists, non‐medical professionals with a university master degree (such as psychologists and biologists), and nurses and technologists. Indices of preceding practical experience and theoretical knowledge are presented in Appendices 1 and 2 . These guidelines are a European standard. They may be adapted in the future according to new scientific insights. National certification programs that comply with these guidelines may be subject to homologation by the ESRS.

Investigating couples' sleep: an evaluation of actigraphic analysis techniques.

‘Blip’ analysis, fast wavelet transformations (FWT) and correlation analysis have all been used to actigraphically assess the impact one person is having on anothers sleep, yet no review exists as to the differences between, and applicability of, these methods for investigating couples’ sleep. Using actigraphy data and audio sleep diaries collected from 18 couples, this paper provides such a review. This paper constructs and assesses two novel, analytical methods: Lotjonens sleep/wake algorithm, and the partner impact on sleep wake analysis (PISWA). Both ‘blip’ analysis and correlation suggest that the strongest relationship between bed partners occurs on an epoch‐to‐epoch basis. However, ‘blips’ deal strictly with onset of movement and fail to incorporate strength and duration of movement. Conversely, correlation analysis incorporates some elements of strength and duration of movement but makes identification of onset problematic. FWT offer useful ‘relativistic’ pattern recognition, identifying onset, strength and duration of movement, but are difficult to quantify. Although audio diary data support the potential of Lotjonens sleep/wake algorithm to identify sleep non‐movement, sleep movement, wake non‐movement (or quiet wakefulness) and wake movement, the problem remains that this method also relies on visualization. Of most promise, we argue, is the PISWA, which examines ‘impact’ of bed partners through incorporating elements of ‘blip’ analysis and the sleep/wake algorithm.

Dissociating Effects of Global SWS Disruption and Healthy Aging on Waking Performance and Daytime Sleepiness

STUDY OBJECTIVE To contrast the effects of slow wave sleep (SWS) disruption and age on daytime functioning. DESIGN Daytime functioning was contrasted in three age cohorts, across two parallel 4-night randomized groups (baseline, two nights of SWS disruption or control, recovery sleep). SETTING Sleep research laboratory. PARTICIPANTS 44 healthy young (20-30 y), 35 middle-aged (40-55 y), and 31 older (66-83 y) men and women. INTERVENTIONS Acoustic stimulation contingent on appearance of slow waves. MEASUREMENTS AND RESULTS Cognitive performance was assessed before sleep latency tests at five daily time-points. SWS disruption resulted in less positive affect, slower or impaired information processing and sustained attention, less precise motor control, and erroneous implementation, rather than inhibition, of well-practiced actions. These performance impairments had far smaller effect sizes than the increase in daytime sleepiness and differed from baseline to the same extent for each age group. At baseline, younger participants performed better than older participants across many cognitive domains, with largest effects on executive function, response time, sustained attention, and motor control. At baseline, the young were sleepier than other age groups. CONCLUSIONS SWS has been considered a potential mediator of age-related decline in performance, although the effects of SWS disruption on daytime functioning have not been quantified across different cognitive domains nor directly compared to age-related changes in performance. The data imply that two nights of SWS disruption primarily leads to an increase in sleepiness with minor effects on other aspects of daytime functioning, which are different from the substantial effects of age.