SLEEP DISORDERS Flashcards
What are the functions of sleep?
Cognitive processing e.g. memory consolidation
Emotional regulation
Metabolic e.g. tissue repair, protein synthesis, hormone secretion, glucose relation, appetite control
Growth of nerve cells
Regulation of bp
Immune regulation
What are some problems with not getting enough sleep?
Psychiatric problems can be made worse
Increased risk of dementia
Increased rates of accidents, particularly RCTs
Reduced cognitive performance
Physical health problems e.g. T2 Diabetes, CVD, poor immune system, hypertension, stroke, kidney disease
Reduced fertility
Reduced QOL
How much sleep do we need as adults?
7-9 hours
(Once over 65 you only need 7-8 hours)
How is sleep studied?
Using a polysomnography
What does a polysomnography measure?
brain activity (EEG), eye movements (EOG), muscle activity or skeletal muscle activation (EMG), and heart rhythm (ECG)
Outline the structure of sleep?
Sleep begins with a short period of NREM stage 1 -> stage 2 -> stage 3 -> stage 4
Then it moves onto REM sleep
This cycle continues 4-6 times
The first NREM-REM cycle is 70-100 minutes and after this they are 90-120 minutes
How does the structure of the sleep cycle change as sleep progresses?
In normal adults, REM sleep increases as the night progresses and is longest in the last 1/3rd of the sleep episodes
As the sleep episode progresses, stager 2 begins to account for the majority of NREm and stages 3+4 may disappear altogether
What are the stages of sleep?
Awake
Drowsy/relaxed
Stage 1 sleep
Stage 2 sleep
Stage 3 sleep
Stage 4 sleep
REM sleep
What does drowsy/relaxed state look like on polysomnography?
Alpha waves
What does an awake state look like on polysomnography?
Beta waves (highest frequency, lowest amplitude EEG)
What does stage 1 state look like on polysomnography?
Theta waves (4-7Hz and some alpha waves)
What does stage 2 state look like on polysomnography?
Sleep spindles (sigma waves) and K complexes (negative sharp waves followed by positive slow waves)
What do stage 3 and 4 states look like on polysomnography?
Delta waves (lowest frequency, highest amplitude EEG)
What does REM sleep look like on polysomnography?
High (fast waves) and mixed frequency with low voltage
When does dreaming occur during sleep?
Dreams can happen during any stage of sleep, but the vivid ones that you remember tend to happen during REM sleep.
Why do we remember some dreams and not others?
It depend as when you wake
If you wake during the REM period you are likely to remember it
As we sleep, the REM portion of our sleep cycle becomes longer, and we’re more able to remember those dreams
When do we have the most energy-intensive sleep?
In REM sleep
Our heightened brain activity requires more glucose, leading to a higher metabolism
What proportion of the sleep period is spent in NREM:REM?
NREM is 75-80% of total time spent asleep
REM is 20-25%
How long is NREM stage 1 and what are its characteristics?
1-7 minutes
Easily interrupted by disruptive noise
How long is NREM stage 2 and what are its characteristics?
10-25 minutes and lengthens with every successful cycle, eventually constituting between 45-55% of a total sleep episode
Requires more intense stimuli than in stage 1 to awaken
The sleep spindles are important for memory consolidation; those who learn a new test have a significantly high density of sleep spindles
How long is NREM stage 3+4 and what are its characteristics?
Stage 3 lasts a few minutes and stage 4 lasts 20-40 in the first cycle
The arousal threshold is highest for all stages in stage 4
How is REM sleep characterised?
Desynchronised brain activity
Muscle atonia
Bursts of rapid eye movements
Why do we not act out our dreams?
Loss of muscle tone and reflexes prevents us from acting them out
Inhibition of motor neurons in the spinal cord and removal of brainstem excitatory inputs to motor neurones
Whats the 2 process model for sleep-wake regulation?
Process S promotes sleep and process C maintains wakefulness
What regulates process C?
Circadian system
What regulates process S?
Neurones in the preoptic area of the hypothalamus that inhibit neuronal communication and turn off the arousal systems during sleep
What is cicrcadium rhythm?
the 24-hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment.
What do circadian rhythms control?
Sleep-wake cycle
Physical activity
Food consumption
Regulate body temp, HR, muscle tone and hormone secretion over the day
What regulates circadian rhythms?
Suprachiasmatic nucleus
What is the suprachiasmatic nucleus?
2 paired nuclei located in the anterior part of the hypothalamus
It received direct inputs from photoreceptor cells in retina along the retinohypothalamic tract.
Norepinephrine is released from SCN of hypothalamus
It regulates rhythmic secretion of melatonin from pineal gland
= sleep induction
When are melatonin levels highest?
At night
Associated with an increase in tiredness
How can melatonin production be inhibited?
Exposure to blue-wavelength light
(Avoid electronic devices before bedtime)
What areas of the brain are responsible for sleep?
Visual cortex
Motor cortex
Hippocampus
Amygdala and cingulate gyrus
Why is it suggested that dreaming may be necessary to recover from traumatic experiences?
Dreaming reduces the reactivity of the amygdala and helps restore functioning of the prefrontal cortex. This supports emotional regulation
It allows emotional content of memories to be processed and stored in autobiographic memory
How does sleep change across the lifespan?
In babies sleep is polyphasic
By age 4 sleep is biphasic
After that sleep is monophasic
At what point after being awak is our drive for sleep strong?
16 hours fo wakefulness
What causes the drive for sleep?
A build up of adenosine
Why does coffee keep us awake?
It’s an adenosine antagonist
What are the sleep hygiene advice?
• exposure to light in day and dark room at night
• Avoid screens before sleep and try relaxation techniques
• Try to avoid baths near bed time and avoid large meals
• Alcohol, drugs, stress can disturb homeostatic sleep drive
• Importance of regular bedtime and waking time
• Desireabilitu of bedtime in late evening
• Dont go to bed too early
• Avoiding napping (relieves adenosine based drive)
• Risks of shift work to sleep pattern
• Exercise during the day
• Eliminate stimulates e.g. alcohol, caffeine, nicotine
• Condition the brain by only use the bed for sleeping and sex
• Do not lie awake for longer than 15 minutes. Get yp and do another relaxing activity and then try sleeping later
What is the reticular activating system?
a complex bundle of nerves in the brain that’s responsible for regulating wakefulness and sleep-wake transitions
It’s found in the anterior-most segment of the brainstem and received input from spinal cord, sensory pathways, thalamus and cortex
What are the nuclei that make up the RAS?
locus coeruleus, raphe nuclei, posterior tuberomammillary hypothalamus, and pedunculopontine tegmentum
What neurotransmitters are used in RAS?
acetylcholine, serotonin, noradrenalin, dopamine, histamine, and hypocretin (orexin)
What types of medications can be used to promote sleep?
acetylcholine, serotonin, noradrenalin, dopamine, histamine, and hypocretin (orexin) antagonists
GABA, adenosine and melatonin agonists
What are the types of sleep disorders?
Insomnia
HYPERSOMNIA
Parasomnia
Circadian rhythm disorders
Sleep-related breathing disorders
Movement disorders
What is insomnia?
difficulty in getting to sleep, difficulty maintaining sleep, early wakening, or non-restorative sleep which occurs despite adequate opportunity for sleep and results in impaired daytime functioning.
Whats the difference between short-term and chronic insomnia?
Short-term - Insomnia symptoms occurring for less than 3 months duration (typically a few days or weeks).
Chronic insomnia - Insomnia symptoms occurring on at least 3 nights per week for three months or more.
What can cause short-term insomnia?
Very common
Stressful events such as bereavement, illness, changes in employment, exams, pending deadlines or financial difficulties.
Changes in sleeping patterns due to the birth of a child or environmental disturbance such as excess noise or light or extremes of temperature.
What can cause chronic insomnia?
Psychiatric disorders such as anxiety and depression.
Medical disorders such as COPD, heart failure, neurodegenerative diseases, malignancy, musculoskeletal conditions and chronic pain.
Substance misuse such as alcohol and illicit drugs
Physical - pain, urinary frequency, breathing difficulties
Environmental - noise shift work, jet lag
Whats the prevalence of insomnia?
Around 1/3rd of adults in Western countries experience sleep problems at least once a week with 6-10% fulfilling the criteria for insomnia disorder
Prevalence of insomnia is 1.5–2 times higher in females than males
most common in older adults
Prevalence of insomnia is higher in people with comorbid conditions e.g. COPD or chronic pain
What are the complications for insomnia?
Cognitive difficulties such as impaired memory, attention, and concentration.
Decreased quality of life and function including:
Impaired work performance and increased work absenteeism.
Increased risk of motor vehicle accidents.
Increased risk of falls in older people.
Psychiatric complications including anxiety, depression and substance misuse.
Medical complications - particularly CVD and T2 diabetes
A possible increase in all-cause mortality
What are some daytime symptoms of insomnia?
fatigue, decreased mood or irritability, malaise, and cognitive impairment.
How do we manage all insomnia conservatively?
Sleep diary
Address precipitating factors
Sleep hygiene
Metronome or ticking clock at <60bpm
How do we manage short term insomnia that causes significant distress?
if sleep hygiene fails and symptoms are likely to resolve soon - 3-7 days of a non-benzodiazepine hypnotic drug ‘Z drug’
• If sleep hygiene fails and symptoms unlikely to resolve soon - CBT and then consider adjunctive hypnotic (Z drug or prolonged release melatonin if >55 years old)
How do we manage insomnia disorder (i.e. >3 months history)?
• CBT
• Avoid pharmacological treatment if possible / but if severe then use Z drugs (preferably <once a week) or modified-release melatonin if >55 (for 3 weeks, extended by up to 10 weeks if effective)
What are the Z-drugs?
These are non-benzodiazepines - psychoactive drugs that are very like benzos
Zopiclone
zolpidem
What is hypersomnia?
Excessive sleepiness that manifests as either a prolonged period of sleep or sleep episodes that occur during normal waking hours. Peristss for 1 month of longer.
How do we grade someone on their sleep?
Epworth sleepiness scale
What can cause hypersomnia?
Insufficiency sleep syndrome (most common)
Depression
Neurological disorders
Sedating medication
Primary sleep disorders
What is insufficiency sleep syndrome?
a lack of adequate habitual sleep results in daytime sleepiness
What are the 2 types of primary sleep disorders?
Parasomnia sleep disorders.
Dyssomnia sleep disorders
What are parasomnia sleep disorders?
These cause abnormal activities during sleep
E.g. sleep terrors, sleepwalking, nightmare disorder, sleep-related eating disorder and sleep paralysis
What are dyssomnia sleep disorderS?
These cause trouble falling asleep or staying asleep. Perhaps the most well-known dyssomnia is obstructive sleep apnea.
What is sleep apnoea?
a sleep-related breathing disorder characterized by recurrent episodes of complete or partial obstruction of the upper airway during sleep, causing apnoea or hypopnoea (decreased airflow), respectively.
This is usually associated with symptoms such as excessive daytime sleepiness, irregular breathing at night, and cycles of transient arousal from sleep to restore normal airway muscle tone and airflow.
What causes sleep apnoea?
When the muscles of the throat relax during sleep it causes a narrowing that obstructs there airway leading to briefing interruption.
It occurs due to excessive collapsing forces around the pharynx that exceed the decreased muscle tone during sleep.
What are risk factors for sleep apnoea?
increasing age
male sex
obesity
family history of OSAS
nasopharyngeal obstruction (for example adenotonsillar hypertrophy)
craniofacial abnormalities
neuromuscular disorders
lifestyle factors (such as smoking, alcohol, and sleeping supine).
When should a diagnosis of obstructive sleep apnoea be suspected?
Suspect if…
Excessive daytime sleepiness, snoring, and fatigue.
Witnessed breathing pauses, gasping, or choking while sleeping.
Unrefreshing sleep, impaired concentration.
Unexplained morning headache (typically resolves within hours of waking).
Frequent nocturnal awakenings.
Unexplained nocturia.
Nocturnal gastro-oesophageal reflux disease (GORD).
Associated conditions such as obesity, depression, hypertension, or stroke disease.
Who needs urgent referral to a sleep clinic?
Has excessive sleepiness impacting on their role as a professional driver or other safety-critical worker (for example pilot, bus or lorry driver, or operator of dangerous machinery).
Has a comorbid condition such as COPD, poorly controlled arrhythmia, nocturnal angina, heart failure, treatment-resistant hypertension, pulmonary hypertension, or respiratory failure.
Is pregnant.
Is undergoing pre-operative assessment for major surgery.
Has non-arteritic anterior ischaemic optic neuropathy.
What is used to confirm a diagnosis of obstructive sleep apnoea?
Polysomnography (PSG) or a limited sleep study
How is obstructive sleep apnoea managed?
Lifestyle changes - weight loss, stopping smoking, reducing alcohol, avoiding sedatives
CPAP (first line for mod-sev)
Mandibular advancement device
Upper airway surgery if evidence of nasopharyngeal obstruction
How does CPAP work to treat OSA?
Airway pressure may be delivered through a nasal or face mask for airflow delivery at night, and the pressure acts to splint the upper airways to prevent collapse during inspiration.
How do Mandibular advancement devices help treat OSA?
Mandibular advancement devices consist of plates made to fit the upper and lower teeth to be worn during sleep, and vary in complexity and cost. They provide forward advancement of the mandible and attached tongue during sleep, to maintain an open upper airway and reduce airway collapsibility.
What is narcolepsy?
A long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes.
What proportion of those with narcolepsy also have cataplexy?
About 70% of those affected also experience episodes of sudden loss of muscle strength, known as cataplexy
Whats the classic tetrad of narcolepsy?
Excessive daytime sleepiness with irresistible sleep attacks
Cataplexy
Vivid hallucinations - Hypnagogic or hypnopompic
Sleep paralysis
What are the 2 main types of narcolepsy?
Type 1: Narcolepsy with Cataplexy
Type 2: Narcolepsy without Cataplexy
Whats the cause of narcolepsy?
Although the cause of narcolepsy is not completely understood, current research suggests that narcolepsy may be the result of a combination of factors working together to cause a lack of hypocretin
Nearly all people with narcolepsy who have cataplexy have extremely low levels of the naturally occurring chemical hypocretin, which promotes wakefulness and regulates REM sleep. Hypocretin levels are usually normal in people who have narcolepsy without cataplexy.
Why is narcolepsy with cataplexy considered an autoimmune disorder?
Researchers believe that in individuals with narcolepsy and cataplexy, the body’s immune system selectively attacks the hypocretin-containing brain cells because of a combination of genetic and environmental factors.
What is cataplexy?
transient muscle weakness triggered by emotion (e.g. anger/extreme laughing) and is a specific feature of narcolepsy.
It is muscle atonia during wakefulness which causes body paralysis or weakness. It often begins in the facial muscles and neck and can manifest with slackening of the jaw or brief dropping of the head. However, episodes can be more dramatic and, if the trunk and limb muscles are affected, can result in collapsing to the ground
Can last from a few seconds to 2 minytes
What is sleep paralysis?
a state, during waking up or falling asleep, in which one is conscious but is unable to move or speak During an episode, one may hallucinate (hear, feel, or see things that are not there), which often results in fear.
Episodes generally last less than a couple of minutes
What can cause sleep paralysis?
Not clear but it has been linked to
Insomnia, disrupted sleeping patterns, narcolepsy, PTSD, GAD, panic disorder, Fhx of sleep paralysis
How is narcolepsy managed?
good sleep hygiene e.g. brief planned naps and sticking to a strict bedtime routine.
Accessing counselling and support may also be important for people to come to terms with the sleep disorder and its implications.
Several medicines are used to treat the symptoms of narcolepsy. These include stimulants such as modafinil, dexamfetamine or methylphenidate (stimulant duering day); sodium oxybate (to help sleep at night); or antidepressants such as SSRI, SNRI or TCAs
Whats the difference between initial, middle and late insomnia?
Initial insomnia is trouble going to sleep - common in mania, anxiety, depressive disorders and substance misuse
Middle insomnia is when you wake in the middle of the night - likely with sleep apnoea and prostatism
Late insomnia is early morning wakening - common in depressive illness and malnutrition
What are examples of non-REM parasomnias?
sleepwalking, sleep terrors, confusional arousals, sexsomnia, and sleep-related eating disorder (SRED)
What are examples of REM parasomnias?
nightmares, REM-sleep behavior disorder, and hypnagogic and hypnopompic hallucinations
What are night terrors?
when the pt wakes abruptly in stage 3 of NREM, usually with vocalisation or sitting up. They may try to escape from the room and will appear very agitated, fearful, tachycardia and sweating due to the sympathetic NS being activated. They usually return to sleep right afterwards. There is often amnesia for the episode and no recall of any dream/nightmare. (Different to nightmares which occur in REM, pt wake up and are able to recall it)
Sleep terrors usually last 1-10 minutes. Usually occur during stage 3/4 of sleep and are therefore predominant in the first 1/3rd of the night.
Who do night terrors typically affect?
0-40% of children have one episode and the peak age is 2-3. Possible in 2% of adults and usually at times of stress.
Whats the treatment for night terrors?
Treatment is to avoid triggers like alcohol and stress, secure the environment, paroxetine and clonazepam.
(Tend to resolve spontaneously by puberty!)
What is sleep walking?
automatic behaviour at night that often occurs in deep NREM. Unresponsive to surroundings and others and there will be no recollection
Whats the treatment for sleep walking?
Treatment is minimise triggers, make environment safe, paroxetine, clonazepam.
What are nightmares?
distressing dreams sometimes with s recurring theme. Pt is orientated on waking and can describe the dream. Especially occur in PTSD and depression.
Who do nightmares typically affect?
10-50% of children aged 3-5 and occasionally occur in up to 50% of adults.
Whats the treatment for recurrent nightmares in those with PTSD?
imagery work
prazosin (reduces central nor adrenergic activity which facilitates REM emotionally processing)
What is REM behaviour disorder?
parasomnia characterized by dream-enactment behaviors that emerge during a loss of REM sleep atonia. RBD dream enactment ranges in severity from benign hand gestures to violent thrashing, punching, and kicking. They can usually be wakened easily and will have good recall. History from partner is crucial and they can be at risk.
Whats the prognosis of REM behavioural disorder?
over 70% will develop parkinsonism or dementia within 12 years of their diagnosis
Whats the treatment for REM behaviour disorder?
safeguard environment and partner, diagnose and treat underlying condition, clonazepam and melatonin may work.
What is delayed sleep disorder?
Recurrent delay in sleep onset and waking times
What are risk factors for delayed sleep disorder?
puberty, use of stimulants e.g. caffeine, irregular sleep
What is advanced sleep phase disorder?
Earlier than desired sleep onset and awakening times
What are risk factors for advanced sleep phase disorder?
Old age
What is jet lag disordr?
Insomnia or hypersomnia due to travel across time zones
What are risk factors for jet lag disorder?
sleep deprivation prior to travel
What is shift-work disorder?
Misaligned circadian rhythm due to nightly working hours and sleep deprivation
What are risk factors for shift-work disorder?
shifts >16 hours and or night shifts
What is non-24 hour sleep-wake disorder?
Inability for individuals biological clock to align with the environmental 24 hours rhythm
What are risk factors for non-24 hour sleep-wake disorder?
Blindness
Impaired light sensitivity
What are examples of circadian rhythm disorders?
Delayed sleep disorder
Advanced sleep phase disorder
Jet lag disorder
Shift-work disorder
Non-24 hour sleep-wake disorder
How can we manage circadian rhythm disorders?
Phototherapy
Melatonin therapy
Good sleep hygeiene
Modafinil if severe
What is modafinil?
a central nervous system stimulant medication used to treat sleepiness due to narcolepsy, shift work sleep disorder, and obstructive sleep apnea
How would you assess obstructive sleep apnoea?
Ask about duration and severity of symptoms, such as snoring, gasping during sleep (apnoeas), and excessive daytime sleepiness including during high-risk activities such as driving.
A collateral history from a partner
The impact of symptoms on quality of life (relationships, mood, sleep, and social activities)
Any impact of symptoms on driving and work-related safety
Any risk factors for OSAS.
Any associated conditions.
Examine the person for Jaw abnormalities such as micrognathia (small jaw) or retrognathia (abnormal jaw positioning with mandible set back from the maxilla). Signs of nasopharyngeal obstruction such as mouth breathing or nasal speech (for example due to adenotonsillar enlargement, nasal polyps, or a deviated nasal septum). Signs of COPD, respiratory failure, or pulmonary hypertension. Blood pressure, body mass index (BMI), and neck circumference in adults.
Consider using a screening questionnaire to assess the extent and severity of symptoms. E.g. STOP-Bang questionnaire or Epworth sleepiness scale.
What is enuresis?
When individuals repeatedly urbanite on themselves whilst asleep
Must happen 2 times a week for >3 consecutive months in someone over 5
What is important to rule out when considering ensuresis as a diagnosis?
UTI
Structural urologic abnormalities
How do we manage enuresis?
Usually children grow out of it and it resolves spontaneously
If it persists then we can use behavioural modification techniques - restricting fluid consumption in evening, voiding at scheduled times before bed, positive reinforcement
Bed wetting alarm
Meds - Desmopressin, imipramine (although the latter as severe side effects so tends to be avoided)
Why is alcohol-induced sleep said to be ‘low quality’?
Alcohol can decrease sleep latency and increase total night sleep time however… it reduces the amount of slow wave sleep and decreases the total amount of REM sleep - these 2 phases are important for memory consolidation, learning and brain development
Alcohol can also cause issues breathing during sleep, particularly for people with sleep apnoea, which can further disrupt sleep quality
