Sleep

Question 1

What is sleep?

Answer 1

Normal, recurring, reversible state in which there is an inability to respond to the external environment.

Question 2

What is unconsciousness?

Answer 2

Lack of full awareness of self and environment.

Question 3

What is consciousness?

Answer 3

Awareness of self and environment, and the ability to respond when stimulated.

Question 4

What is REM sleep?

Answer 4

Rapid eye movement.

Question 5

When does most NREM sleep occur?

Answer 5

At the start of the night.

Question 6

What percentage of sleep for young adults is NREM?

Answer 6

Around 3/4.

Question 7

Describe non rapid eye movement sleep.

Answer 7

• Synchronised rhythmic electroencephalography (EEG) activity, partial muscle relaxation and reduced cerebral blood flow.
• Reduced heart rate, blood pressure and tidal volumes.
• Some non-narrative images.

Question 8

Describe REM sleep.

Answer 8

• Occurs mostly at the end of the night.
• EEG shows fast activity, fMRI (functional MRI) shows increased brain activity - similar to wakefulness.
• Atonic muscles with the exception of diaphragm and extraocular muscles.
• Increased cerebral blood flow and impaired thermal regulation.
• Narrative dreaming.

Question 9

Why is deep sleep essential?

Answer 9

To allow cortex recovery after busy day.

Question 10

What is the function of REM sleep?

Answer 10

• Mainly for early brain development.
• Likely dispensible.
• Seen as “non-wakefulness, not sleep”.

Question 11

Which common drugs suppress REM sleep with no effect?

Answer 11

Tricyclics.

Question 12

Neonates spend 16 hours a day asleep, what percentage of this is REM sleep?

Answer 12

50%.

Question 13

Describe sleeping pattern of the elderly.

Answer 13

Increased awakenings, reduced REM latency and total sleep time and daytime napping.

Question 14

What controls sleep?

Answer 14

• Biology and physiology.
  NOT psychology.
• Circadian rhythm is important for sleep-wake, appetite and hormone secretion.

Question 15

Function of REM sleep?

Answer 15

• Consolidates memory and possibly deletes unnecessary memory files.
• Maintains immunocompetence.

Question 16

What are circadian rhythms?

Answer 16

Endogenously controlled human processes.

e.g. sleep-wake, appetite, body temperature and hormone secretion, alertness.

Question 17

Normal circadian rhythm lasts how long?

Answer 17

24 hours and 20 mins.

Question 18

What entrains the body clock?

Answer 18

• Light. Uses retinal ganglion cells projecting to suprachiasmatic nucleus.
• Non-rod, non-cone cells.

Question 19

There is no clinical evidence to suggest that muscle recovery occurs during sleep, but what does sleep help to repair?

Answer 19

Tissue repair.

Question 20

What peaks during sleep?

Answer 20

• Cell division.

- Skin mitosis.

Question 21

Most effects of lack sleep affect which part of the cortex?

Answer 21

Prefrontal - impaired alertness.

However, old and well rehearsed tasks, routine behaviour and logic tasks remain unaffected.

Question 22

Effects of lack of sleep?

Answer 22

• Irritable, suspicious.
• Visual illusions.
• Microsleeps and concentration lapses.

Question 23

What percentage of RTAs attended by police are sleep related?

Answer 23

= 10%.
Most are acute deprivation.

Double on non-urban roads.

Question 24

Most likely cause of accidental death at work?

Answer 24

Truck driver falling asleep at wheel.

Total loss of truck and load £1.2million.

Question 25

Most studies suggest what length of sleep is acceptable?

Answer 25

7 - 7.5 hours.

Question 26

A mid afternoon nap of 15 minutes is equivalent to how many minutes of sleep overnight?

Answer 26

90 minutes.

Question 27

What are parasomnias?

Answer 27

Abnormal events occurring during sleep.

Question 28

Non-REM parasomnias occur from non-REM sleep, usually when?

Answer 28

During deep sleep - stage N3.

Question 29

What is the most common type of parasomnia?

Answer 29

Non-REM, occurring in up to 20-30% of children.

Question 30

Give some examples of non-REM parasomnias.

Answer 30

- Non-dreaming. - Confusion arousals. - Sleep walking. - Sleep terrors and paralysis. - Bruxism (grinding teeth). - Restless legs and periodic limb movement of sleep (PLMS). These are often complex behaviours.

Question 31

Describe REM parasomnias.

Answer 31

- Often seen preceding parkinson's. - Dreaming. - Much simpler behaviour then NREM parasomnias. - Usually in the latter third of the night.

Question 32

What is narcolepsy?

Answer 32

Rare long-term brain disorder causing someone to suddenly fall asleep at inappropriate times. Sleep disorder characterised by excessive sleepiness, sleep paralysis, hallucinations. Sometimes episodes of cataplexy (partial or total loss of muscle control, often triggered by strong emotion e.g. laughter).

Question 33

Peak ages of narcolepsy onset?

Answer 33

15 and 36.

Question 34

Clinical presentation of narcolepsy?

Answer 34

- Daytime sleepiness. - Cataplexy. - Hypnagogic hallucinations. - Sleep paralysis. - RBD: rem sleep behaviour disorder.

Question 35

What are the features of daytime sleepiness that suggest a diagnosis of narcolepsy?

Answer 35

- Involuntary somnolence during eating/talking. | - Possibly severe and impossible to resist.

Question 36

What is cataplexy?

Answer 36

- "To strike down with fear". - Present in 70% of those with narcolepsy. - Loss of muscle tone often triggered by strong emotion e.g. laughing.

Question 37

What are hypnagogic hallucinations?

Answer 37

Hallucinations which occur at sleep onset.

Question 38

What is sleep paralysis?

Answer 38

Unable to move upon falling asleep or awakening with retained consciousness.

Question 39

What percent of patients with REM sleep behaviour disorder (RBD) have narcolepsy?

Answer 39

Anywhere between 7-36%.

Question 40

What is the delay between narcolepsy onset and diagnosis?

Answer 40

10 years. | 50% of adults report symptom onset as teenagers.

Question 41

What is the impact of narcolepsy?

Answer 41

- Impaired social and academic performance. - Impaired job performance (sleep attacks, memory problems). - Increased risk of death in automobile accidents.

Question 42

Investigation of narcolepsy?

Answer 42

- Overnight polysomnography. - Multiple sleep latency test. - Lumbar puncture.

Question 43

What is a multiple sleep latency test?

Answer 43

- 4 x 25 minute naps scheduled 2 hours apart. - EEG, muscle activity and eye movement are recorded. - Measures time from start of daytime nap to the first signs of sleep (sleep latency). - Patients fall asleep faster if they are sleepier.

Question 44

What is checked in a lumbar puncture in narcolepsy?

Answer 44

CSF hypocretin levels.

Question 45

What CSF hypocretin levels of a lumbar puncture are consistent with narcolepsy?

Answer 45

Low i.e. <110pg/ml or 1/3 of the mean control value.

Question 46

What advice should be given to someone with narcolepsy with regards to driving?

Answer 46

Cease driving on diagnosis until control is achieved. Permanently excluded from driving Group 2 (lorries and buses).