Curriculum standards: LG12: Scientific foundations of sleep medicine (including investigations and measurements)

Knowledge guides

LG12: Scientific foundations of sleep medicine (including investigations and measurements)

Epidemiology, pathophysiology, and clinical sciences

Advanced Trainees will have in-depth knowledge of the topics listed under each clinical sciences heading.

For the statistical and epidemiological concepts listed, trainees should be able tdescribe the underlying rationale, the indications for using one test or method over another, and the calculations required tgenerate descriptive statistics.

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Investigations, procedures, and clinical assessment tools

Advanced Trainees will know the scientific foundation of each investigation and procedure, including relevant anatomy and physiology. They will be able tinterpret the reported results of each investigation or procedure.

Advanced Trainees will know how texplain the investigation or procedure tpatients, families, and carers, and be able texplain procedural risk and obtain informed consent where applicable.

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Important specific issues

Advanced Trainees will identify important specialty-specific issues and the impact of these on diagnosis, management, and outcomes.

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Pathophysiology of normal and abnormal sleep

Anatomy and physiology of upper airway
- Changes of the above with age and maturity, from the neonatal period through adolescence
- Concept of the pharyngeal airway as a collapsible tube
- Dynamic behaviour of the pharynx during breathing, when awake and asleep, and the concept of critical pressure
- Effects of craniofacial structure, obesity, upper airway muscle function, and ventilatory control on upper airway patency
- Effects of nasal resistance on pharyngeal collapsibility
- Role of upper airway muscles in the control of breathing when asleep and awake
- Structure and functions of the upper airway
Physiology of sleep and breathing
- Breathing changes during sleep, and REM versus NREM sleep
- Control of breathing during sleep:
  - central and peripheral chemoreceptors, and hypoxic and hypercapnic ventilatory responses
  - central pattern generator as the basis for respiratory control
  - effect of sleep on respiratory neurons
  - neuroanatomical and neurophysiologic basis of control of breathing
  - normal expected changes with age and development, including the effects of prematurity on these systems
  - peripheral and central afferents and inputs
- Effect of sleep on breathing in respiratory and neuromuscular diseases
- Effect of sleep on other systems, including cardiovascular, gastrointestinal and neurological disease (such as decreased seizure threshold in NREM sleep in some epilepsy syndromes)
- Explain the mechanics of breathing in a child / adolescent
Sleep and circadian neurophysiology
- Anatomy and physiology of the circadian system
- Circadian, homeostatic, and ultradian processes that underpin sleep
- Circulating hormones and inflammatory cytokines’ impact on sleep-wake patterns
- Cultural, physical environmental, and social factors’ impact on sleep
- Distinctions between REM and NREM sleep
- Effects of sleep deprivation in terms of health and daytime functioning
- Impact of circadian and homeostatic systems on sleep-wake cycles and propensity daytime sleepiness
- Influence of NREM and REM sleep and sleep arousal on cardiovascular, endocrine, gastrointestinal, and respiratory physiology, and the neurohormonal and circadian factors that might underpin these effects on different biological systems, such as the understanding of why asthma is worse in sleep
- Influence of NREM and REM sleep and sleep arousal on the autonomic nervous system
- Interactions between sleep and wakefulness and the sensory nervous system, perception and cognition, the cardiovascular system, temperature regulation, and the endocrine system
- Molecular and neural basis of the circadian system
- Neuroanatomical and neurophysiological basis for arousal from sleep
- Neuroanatomical, neurobiological, and neurophysiological basis for sleep and wakefulness and for REM versus NREM sleep
- Normal sleep architecture, including the current classification of sleep stages, normal arousal patterns, and normal sleep movements
- Ontogeny of sleep and breathing irregularities in sleep
- Psychophysiology of the drowsy state
- Sleep stages
- Sleep structure and sleep architecture changes with age, from the neonatal period through adolescence

Assessment tools

Actigraphy
Computerised polysomnography (PSG) systems
Hardware and software of the computerised equipment used in a sleep service
Scoring of:
- arousals
- cardiac events
- movements
- respiratory events
- sleep
Sensor devices used measure physiological variables as part of sleep studies
Sleep diaries
Sleep monitoring equipment

Procedures / Treatments

Compliance monitoring (remotely or locally)
Mask fitting, including acclimatisation, and troubleshooting for positive airway pressure (PAP) therapy
Medication
Non-pharmacological treatment, such as cognitive behavioural therapy for insomnia (CBT-I)

Sleep measurement and investigations

Indications for sleep investigations:
- circumstances when sleep investigations are not indicated
- clinical features, mechanisms, and specific measurements of common sleep disorders
- common questionnaire measurements of sleepiness and quality of life scores, and know the limitations of these measurements
- effects of medications and comorbidities, such as psychiatric and medical conditions and lifestyle, on sleep-wake patterns, and how these factors can affect measurements of sleep propensity
- indications and use of tests for sleep propensity
- indications for investigation with type I-IV devices
- the role of (PSG) in sleep disorders that are predominantly behavioural
- what measurements are possible and appropriate for disorders listed in the International Classification of Sleep Disorders (ICSD-3)
Principles of measurement parameters:
- basic principles underlying the recordings of bioelectrical signals, such as appropriate filters, frequency, understanding of common artefacts in PSG
- measurements across the range of sleep studies, and determine adequacy of recording techniques
- measurements indicated for further evaluation in the event of a non-diagnostic sleep study
PSG recording, including normal and abnormal patterns:
- age-appropriate normal sleep stage distribution and proportions
- arousals
- infant sleep scoring versus standard paediatric sleep scoring
- periodic limb movements (PLMs)
- raw data from sleep studies, including:
  - airflow parameters
  - airway pressures
  - body position
  - chin electromyography
  - effort parameters
  - ECG
  - electroencephalogram (EEG)
  - electro-oculogram (EOG)
  - leg electromyography derivations
  - measures of CO2 (end tidal versus transcutaneous and their pros and cons)
  - oxygen saturation
- REM sleep without atonia (RSWA)
- respiratory events:
  - apnoeas – central, mixed, and obstructive
  - hypopnoeas
  - respiratory effort related arousals
- scoring criteria, and recognising how different scoring criteria may alter results and therefore interpretation of severity

The use of scoring concordance software

Appropriateness of performing sleep investigations based on clinical features
Brain CT scan
Brain MRI scan
Cephalometry
Chest x-ray
Continuous oximetry and measurements of CO2 in sleep
Diaphragmatic electromyography monitoring
Diaphragm testing (e.g. SNIFF test)
Drug-induced sleep endoscopy (DISE)
Limited channel sleep studies:
- cardiorespiratory sleep studies
- limited channel PSG studies
- overnight oximetry
- safety and technical limitations of studies performed in the home
Maintenance of wakefulness test (MWT)
Methods of measuring respiration during sleep
Multiple sleep latency test (MSLT)
Oesophageal pressure monitoring
PAP titration and review studies
PLMs
Questionnaire measurements for sleepiness and sleep disorders
Repeat investigations
Respiratory function tests to assess sleep breathing disorders:
- arterial blood gases (role of capillary and venous blood gas measurements)
- cardiopulmonary exercise testing, and other tests of ventilatory response
- fitness to fly / hypoxic challenge
- gas transfer
- lung volumes
- oximetry
- spirometry
- tests of respiratory muscle strength (including peak cough flow)
Sensitivity of the different measurements of respiration
Sleep investigation report
Sleep propensity tests
Upper airway imaging
Upper airway examination, including nasoendoscopy
Video and EEG during paroxysmal events at night

Explain sensors, filters, gain, sampling times (frequencies), and linearity of the equipment used in the sleep laboratory to technical and other staff
Infection control and prevention of cross-infection
Influence of other disease processes on common measurement parameters, including:
- cardiovascular disease, such as heart failure
- chronic respiratory illness, such as cystic fibrosis
- epilepsy and its treatments, such as effect of antiepileptics on sleep EEG
- obesity
- prematurity
- respiratory muscle weakness
- stroke
Limitations and common parameters in sleep investigation
Referring (where appropriate), depending on sleep disorder (e.g., dentist, dietitian, neurologist, respiratory physician, sleep psychologist)
Teach patients, their families, health professionals, and the public about the nature and importance of normal sleep