Consciousness and Sleep

Question 1

What is consciousness?

Answer 1

a state of awareness of the self and the environment

Question 2

What are the 3 dimensions of unconciousness?

Answer 2

1. coma (death)
2. deep sleep
3. unconscious mind

Question 3

What are the 3 steps from normal consciousness to coma (including coma)?

Answer 3

clouding = drowsiness/agitation with memory disturbance and disorientation, impaired attention, concentration, recognition, comprehension, understanding and judgement 
drowsiness = tendency to drift into sleep without sensory stimulation, slow actions, slurred speech, reduced reflexes and muscle tone 
coma = reduced eye opening, verbal response and motor response

Question 4

What is delirium tremens (DT)?

Answer 4

acute confusional state often seen as a withdrawal symptom in chronic alcoholics and cause by sudden cessation of alcohol intake.
- anxiety, terror, sweating, vivid and terrifying visual or sensory hallucinations

Question 5

What are some characteristics of normal perception?

Answer 5

• we are able to distinguish perceiving with our sense organs for imagining the same objects
• when we perceive something, we realise its possible relevance to our emotion or actions
• normal sensation has a quality of objectivity
• the observer feels certain that the object exists even if no one else is experiencing it at the same time
• experience of object perception is involuntary
• quality of independence

Question 6

What are the two times of abnormal perception?

Answer 6

sensory distortions i.e. intensity and quality of perception and associated feelings
false perceptions e.g. illusions, hallucinations, pseudo hallucinations

Question 7

What are the three types of illusion?

Answer 7

Completion illusion = you fill in the missing gaps
Affect illusions = these are dependent upon an individuals mood state e.g. being scared leads to incorrectly interpreting a shadow
Pareidolic illusions = these illusions arise due to excessive fantasy thinking e.g. seeing faces in things

Question 8

What is a hallucination?

Answer 8

A percept like experience:

• in the absence of an external stimulus
• which has the full force and impact of a real perception
• which is unwilled, occurs spontaneously and cannot be readily controlled by the subject

Question 9

What is a pseudo hallucination?

Answer 9

A hallucinations which the patient releases is not real

e.g. hearing voices in your head, compared to saying ‘people were talking around me’

Question 10

What is the behavioural definition of sleep?

Answer 10

recurrent regular reversible state characterised by quiescence and diminished responsiveness to external cues:

• lack of mobility
• closed eyes
• reduced response to external stimulation
• characteristic sleeping posture
• reversible unconscious state

Question 11

What measurements are taken in polysomnography?

Answer 11

electroencephalogram (EEG) = brain waves
electrooculogram (EOG) = eye movement
electromyegram (EMG) = muscle tension

Question 12

What are the neurophysiological definitions of sleep?

Answer 12

according to brain activity measured by EEG
Wakefulness: 
eyes open --> beta rhythm 
eyes closed --> alpha rhythm 
Sleep: 5 phases
1 = 5%, alpha waves <50%, alpha, theta transition 
2 = 55%, sleep spindle, k-complex
3 = 5%, delta waves, 20-50%
4 = 10%, delta waves, >50%
REM = theta waves, PGO waves, REM, atonia, sympathetic tone increased 
4-6 cycles/night of around 90mins each
REM duration increase with each cycle

Question 13

What are the physiological determinants of sleepiness?

Answer 13

sleep drive, homeostasis, forebrain, adenosine

circadian drive for wakefulness (supra chiasmatic nucleus)

Question 14

Give an example of a clock gene
What does it two?
What happens if it is deleted?
What is autoregulation?
What is coordination? What is the master clock synchroniser?
What is the average free-running intrinsic period?

Answer 14

Clock genes: Bmal 1 (Mop 3) only non-redundant clock gene: deletion causes immediate loss of circadian rhythm in constant darkness (no re-setting by light)

• autonomous tissue-specific oscillators in mammals: many tissues (SCN, liver, heart) demonstrate circadian oscillation and clock gene expression allows tissue specific ‘fine tuning’
• autoregulation = maintain oscillatory mechanism using transcriptional and translational feedback loops to up or down regulate clock settings
• co-ordination = SCN is master clock synchronising circadian rhythm via neural and endocrine regulators. Average free-running intrinsic period = 24.18 hours

Question 15

What are the 3 main causes of excessive sleepiness?

Give examples of each

Answer 15

sleep-wake dysregulation - narcolepsy, idiopathic/recurrent/post-traumatic hypersomnia,
sleep disruption - OSAHS, depression, parasomnias, RSBD
circadian malalignment - shift work disorder

Question 16

What is OSAHS?

What is RSBD?

Answer 16

both sleep disruption
OSAHS = obstructive sleep apnoea-hypopnoea syndrome
RSBD = REM sleep behavioural disorder

Question 17

Give some examples of slow-wave sleep disorders

Answer 17

stage 4 nonREM sleep arousal disorders
sleep walking = motor activity - walking. independent complex behaviour can occur e.g. dressing and even eating
night terrors = screaming, autonomic hyperarousal sweating, confusion, rapid heart rate

Question 18

What are the common features of slow-wave sleep disorders?

Answer 18

common especially in children
usually unaware of their activity
aeitiology unknown 
risk of injury: forensic aspects 
injury prevention is the primary objective of management

Question 19

Describe REM sleep disorders

Answer 19

• presence of muscle tone during REM sleep associated with active complex behaviours in absence of eplileptiform activity
• act out dramatic and/or violent dreams during REM sleep
• usually amnesia for voluntary muscle activity but can remember dream
• onset 90mins after sleep
• shouting and grunting / assaulting spouse/partener

Question 20

What are the clinical features of Restless Legs Syndrome?

Answer 20

• dyaesthesias (unpleasant sensations) in the legs creeping, crawling, tingling, pulling, pain
• relief with voluntary movement and associated motor hyperactivity
• irresistible urge to move the legs, walk, massage when experiencing dyasthesias
• suppression of activity produces increasing discomfort

Question 21

What is narcolepsy?

Answer 21

• fall asleep uncontrollably throughout the day for periods between 1-30mins
• even when engaged in an activity
• abnormal sleep pattern: decreased REM latency
• classic symptoms include cataplexy, sleep paralysis, and hypnogogic hallucinations

Question 22

What is obstructive sleep apnoea?

Answer 22

• brief interruptions of breathing during sleep
• apnoeic events = breathing pauses, up to 30/hour
• central control of respiration not initiated
• decrease pO2 and increase CO2, central mechanisms to open airway (grunt/gasp)
• clinical symptoms = sleepiness, hypertension, irritability, poor concentration, obestity

Question 23

What are the management option for OSA?

Answer 23

• sleep hygiene, positioning, weight loss
• modafinil 200mg, last dose midday
• continuous positive airway pressure via mask into nasal passages to keep airway open
• surgery - remove obstruction

Question 24

What is the definitions of insomnia?

Answer 24

Perception or complaint of inadequate or poor-quality sleep

• difficulty falling asleep (early)
• waking up frequently during the night with difficulty returning to sleep (middle)
• waking up too early in the morning (late)
• unrefreshing sleep
• causes tiredness, lack of energy, irritability
• transient <2 weeks
• intermittent 2-4 weeks
• chronic >month

Question 25

What are the risk factors for insomnia?

Answer 25

increased age
female
psychiatric disorders: depression, anxiety
medical disorders: hyperthyroidism, chronic pain
substances: caffeine, nicotine, alcohol
other: shift work, exercise, sleep apnoea
iatrogenic

Question 26

What are the non pharmacological interventions for insomnia?

Answer 26

avoid excacerbents
pleasant comfortable, dark environment 
regular schedule
reconditioning
cognitive reconstructing 
relaxation therapy
sleep restriction

Question 27

What are the pharmacological interventions for insomnia?

Answer 27

sedatives

no difference between short acting BZD and Z-drugs