Preface

For progress to be maintained in a clinical field like sleep medicine, unimpeded, unrestricted access to data and the advances in clinical practice should be available. The reason this book is exciting is that it breaks down the barriers to dissemination of information. Researchers at the forefront of areas that have limited funding can find it difficult to get data from randomised, double-blind, (placebo-controlled), crossover or parallel group studies, etc., and so may be limited to the lowest level of scientific research, i.e. single case, or restricted observational series.

Nonetheless, data is data, and whilst the interpretation may be suspect (which can happen with even the best controlled studies), the data is the most valuable asset in a research paper. Of course insight that either consolidates or furthers our understanding is vital, but without data it can be nothing more than an armchair idea. Many journals require the highest levels of scientific rigour, which may make some research inaccessible - really a form of scientific censorship. Also established areas, or newly established areas can develop castes of mind that censor material by exclusion. Finally, access to scientific material can be very expensive. There are now numerous sleep journals but only larger departments are likely to be able to pay for these so a publisher that allows ready and free internet access has to be welcomed.

The chapters in this book reflect leading edge ideas, reflections and observations. Even though the modern era of sleep research evolved from Aserinksky's observations of rapid eye movements in the sleep of babies, most work is nonetheless done in adults. There is much less formal work done in youngsters and virtually none *in utero* and pregnancy itself is virtually unexplored. So, Dr Miller *et al*'s chapter reviewing sleep in pregnancy is particularly welcome as it incorporates current thinking in how disordered sleep impacts other adult pathological processes. Dr Tomoda and Dr Yamakazi's datadriven chapter on adolescents with sleep disturbance focuses on metabolic and endocrine data which sheds light on why gastrointestinal distress may arise in some children. Dr Silvestri and Dr Aricò's review examines the interrelationship of sleep disorders with the growing problem of Attention Deficit/Hyperactivity Disorder, a disorder which attracts considerable debate as to the role of sleep as a fundamental component or a state that exacerbates this complex condition.

Dr Kobal Grum and Dr Kobal's interesting work combines naturalistic observations in a quite unique observational setting found in Hg° mines. Armed with these occupational

#### X Preface

data, they consider the pathological mechanisms, given our current understanding of the neurobiology of sleep, that result in sleep disorders in these workers.

Sleep-related breathing disorders dominate sleep medicine so it is not surprising that there are several chapters in this area. The historical division in medicine of physicians and surgeons can be seen in this area or sleep disorders. It is dominated by respiratory physicians. However, surgeons also have a place, depending on the physical structures. Another curiosity in this area is that, whilst sleep apnoea demands treatment because of the adverse physical and social consequences if it is not treated, "snoring" is not regarded as such an urgent problem. However, there is evidence in terms of personal and social consequences as well as its symptomatic value, that highlight the need for more research in this area. Dr Kotecha's chapter is entirely pragmatic and practical, focussing on the evaluation of the upper airway so that the appropriate therapies can be applied.

Dr Del Campo *et al*'s timely chapter on Upper Airway Resistance Syndrome also highlights an area that is subject to discussion. As a diagnostic entity, it is not clear whether it is at one end of the obstructive sleep apnoea continuum or exists in its own right.

Dr Lovati *et al* take the book into another area, the possible bidirectional processes that can affect sleep and other disorders - in their case the two-way dynamics between sleep and migraine. From another perspective, Dr Rola examines the impact of stroke and neurological disorders on sleep disorders, bringing to the neurologists' attention the need to consider sleep a mediating factor in their nosological entities. Dr Büttner's broad ranging and comprehensive review goes beyond sleep apnoea and considers it and other disorders and their neuropsychiatric consequences on objective measures of performance.

Sleep disorders can be easily classified into three main areas: those that cause unwanted sleep or sleepiness, those that cause unwanted wakefulness and those that involve unwanted behaviours during sleep - the parasomnias. Dr Hizli Sayar and Dr Tarhan's review provides a helpful introduction into this area. Restless Legs Syndrome – a disorder which twenty years ago was 'treated' by a multitude of disparate therapies and which was only unified by its symptomatology. In recent years the mechanisms have become clearer and there is a degree of unification. Dr Taylor-Gjevre and Dr Gjevre's review brings the relevant clinical literature together in one location. The final chapter is extremely helpful in introducing methods of screening and evaluating REM Behaviour Disorder. This disorder is most easily confirmed using sleep laboratory methods (polysomnography and video), but these methods are expensive, so cheaper clinical methods are welcome and are discussed by Dr Miyamoto.

> **Chris Idzikowski**  Director, Edinburgh Sleep Centre and the Sleep Assessment and Advisory Service, Edinburgh, UK

X Preface

right.

performance.

data, they consider the pathological mechanisms, given our current understanding of the

Sleep-related breathing disorders dominate sleep medicine so it is not surprising that there are several chapters in this area. The historical division in medicine of physicians and surgeons can be seen in this area or sleep disorders. It is dominated by respiratory physicians. However, surgeons also have a place, depending on the physical structures. Another curiosity in this area is that, whilst sleep apnoea demands treatment because of the adverse physical and social consequences if it is not treated, "snoring" is not regarded as such an urgent problem. However, there is evidence in terms of personal and social consequences as well as its symptomatic value, that highlight the need for more research in this area. Dr Kotecha's chapter is entirely pragmatic and practical, focussing on the evaluation of the upper airway so that the

Dr Del Campo *et al*'s timely chapter on Upper Airway Resistance Syndrome also highlights an area that is subject to discussion. As a diagnostic entity, it is not clear whether it is at one end of the obstructive sleep apnoea continuum or exists in its own

Dr Lovati *et al* take the book into another area, the possible bidirectional processes that can affect sleep and other disorders - in their case the two-way dynamics between sleep and migraine. From another perspective, Dr Rola examines the impact of stroke and neurological disorders on sleep disorders, bringing to the neurologists' attention the need to consider sleep a mediating factor in their nosological entities. Dr Büttner's broad ranging and comprehensive review goes beyond sleep apnoea and considers it and other disorders and their neuropsychiatric consequences on objective measures of

Sleep disorders can be easily classified into three main areas: those that cause unwanted sleep or sleepiness, those that cause unwanted wakefulness and those that involve unwanted behaviours during sleep - the parasomnias. Dr Hizli Sayar and Dr Tarhan's review provides a helpful introduction into this area. Restless Legs Syndrome – a disorder which twenty years ago was 'treated' by a multitude of disparate therapies and which was only unified by its symptomatology. In recent years the mechanisms have become clearer and there is a degree of unification. Dr Taylor-Gjevre and Dr Gjevre's review brings the relevant clinical literature together in one location. The final chapter is extremely helpful in introducing methods of screening and evaluating REM Behaviour Disorder. This disorder is most easily confirmed using sleep laboratory methods (polysomnography and video), but these methods are expensive, so cheaper clinical

**Chris Idzikowski** 

UK

Director, Edinburgh Sleep Centre and

the Sleep Assessment and Advisory Service, Edinburgh,

methods are welcome and are discussed by Dr Miyamoto.

neurobiology of sleep, that result in sleep disorders in these workers.

appropriate therapies can be applied.

**1** 

*UK* 

**Sleep and Pregnancy: Sleep** 

Michelle A. Miller, Manisha Ahuja

and Francesco P. Cappuccio

*University of Warwick* 

**Deprivation, Sleep Disturbed Breathing** 

There are many factors that can influence an individual's sleep pattern and quantity and quality of sleep. These factors can be cultural, social, psychological, behavioural, pathophysiological and environmental. Sleep patterns can also be influenced by society and by changes within society. In recent times we have seen the introduction of longer working hours, more shift-work and 24-7 availability of commodities. At the same time secular trends of curtailed duration of sleep to fewer hours per day across westernized populations (Akerstedt & Nilsson 2003) has led to increased reporting of fatigue, tiredness and excessive daytime sleepiness (Bliwise, 1996). It is of interest that whilst some studies indicate that women may have better sleep than men in general (Lindberg et al, 1997; Goel et al, 2005), they also report a larger difference in the estimated time of sleep that they believe they require and the actual sleep time they achieve than men. This might indicate that their sleep debt (amount of sleep deprivation) is higher in women than in men (Lindberg et al, 1997). There is now a wealth of evidence to support the epidemiological link between quantity of sleep (short and long duration) and quality of sleep (like difficulties in falling asleep or of maintaining sleep) and cardiovascular risk factors. These include hypertension (Cappuccio et al, 2007; Stranges et al, 2010), type-2 diabetes (Cappuccio et al, 2010a) and obesity (Cappuccio et al, 2008; Stranges et al, 2008; Cappuccio et al 2011a) as well as cardiovascular outcomes (Cappuccio et al, 2011b) and all-cause mortality (Ferrie et al, 2007; Cappuccio et al, 2010b). Additionally, there may be important gender differences in sleep and associated health outcomes (Miller, 2009 et al; Cappuccio et al, 2007). The deleterious effects of sleep deprivation can be seen on a variety of systems within the body, with detectable changes in metabolic (Knutson, et al. 2007; Spiegel, et al. 2009), endocrine (Spiegel, et al. 1999; Taheri, et

al. 2004) and immune pathways (Miller & Cappuccio 2007; Miller et al, 2009).

in pregnant women may also be associated with the risk of gestational diabetes.

The physiological and hormonal changes that occur in pregnancy increase the risk of developing Sleep Disordered Breathing (SDB). It has been estimated that 10-27% of pregnant women may suffer from habitual snoring (Pien & Schwab, 2004) and there is growing evidence to suggest that snoring and sleep apnoea during pregnancy are associated with an increased risk of gestational hypertension and pre-eclampsia. SDB and short sleep duration

**1. Introduction** 

**and Sleep Disorders in Pregnancy** 
