SLEEP DISORDER RESEARCH AND AO2

CHRONIC INSOMNIAPoor sleep that happens most nights and last a month or longer.

Can be caused by a combination of factors e.g.

• Genetic condition affecting sleep mechanisms• Underlying mental or physical disorder• arthritis, • heart failure• Sleep Apnea• Sleep medication!!!

TRANSIENT INSOMNIA- lasting for a few nights – SHORT-TERM INSOMNIA - two or four weeks of poor

sleep

Both can be caused by; Stress , Environmental noise, Extreme temperatures change in the surrounding

environment as well as many other.

INSOMNIA RESEARCHNOFZINGER et al

Caused by OVERACTIVITY of certain brain regions.

Found that in insomniacs – The Brainstem, Hypothalamus and Basal Forebrain were all OVERACTIVE. These parts of the brain regulate sleep.

MEASURED WITH PET SCANS AND EEG (AO2 -Scientific)

GONTZAS et al (2001)

Found insomniacs had High levels of ACTH and CORTISOL (Stress hormones) during sleep.

11 PPTS (AO2 SAMPLE SIZE) – MATCHED PAIRS

AO2 - SCIENTIFIC measurement of STRESS HORMONES.

A02 Practical Application – use of TEMAZEPAM – a depressant/relaxant that may counter the effects of the STRESS HORMONES.

Familial Fatal Insomnia

• A genetic condition which causes a degeneration of the thalamus, usually in a person’s 30s or 40s.

• This degeneration interferes with circadian rhythms and affects:• Sleep; blood pressure; heart rate; core body temperature and

hormone flow.• Eventually leading to death• RESEARCH STRONGLY SUGGESTS THAT FFI IS GENETICALLY

DETERMINED

FFI – RESEARCH

Lugaresi and Montagna (1990)

Family in NORTH EAST ITALY

14 MEMBERS of the family (over THREE GENERATIONS) had the disorder that led to death.

ONSET - usually during the 4TH OR 5TH decade of life

(except one who began showing signs at 19 years old)

A02 – just ONE FAMILY!

Medori et al (1992)

AUTOPSY on BRAIN of TWO individuals with FFI. AO2 – sample size

Used WESTERN BLOT ANALYSIS, a SCIENTIFIC TECHNIQUE in order to analyse PROTEINS in BODY TISSUE.

Found that FFI was caused by a genetic mutation of a protein called PRION. This led to the symptoms of FFI.

AO2

SUBJECTIVE JUDGEMENT OF AMOUNT OF SLEEP WE EXPERIENCE…..

Who’s ever felt you haven’t slept all night??

This is rare!

It may be that we have experienced more sleep than we actually believe.

Familial Fatal Insomnia

• FFI is extremely RARE and this makes the study of this sleep disorder DIFFICULT

• This also means that SAMPLE SIZES also tend to be VERY SMALL.

• BUT – It seems pretty clear that its origin is genetic.

• MASSIVE AO2 Point – is all insomnia so easily explained?

Familial Fatal Insomnia

Conventional drug treatments effective with patients with standard INSOMNIA are seen to be INEFFECTIVE when used on individuals with FFI.

These include SEDATIVES and BENZODIAZEPINES. (Julien et al, 1998)

This draws a CLEAR DISTINCTION between standard INSOMNIA and FFI.

Familial Fatal Insomnia (AO2)

• So it would seem that though a very rare form of insomnia is genetic in origin, the most common form of insomnia is much more complex.

Insomnia (AO2)

• Diathesis-stress model = best explanation• Genetic predisposition eg hyperarousal

(Bonnet and Arand 1995) coupled with environmental stressors that precipitate the disorder.

• Other internal/external factors may perpetuate insomnia (keep it going)

GENERAL AO2

Research in to sleep DISORDERS tends to take place in SLEEP LABS – this is an artificial environment and may effect the sleep of the PPTS.

Sample sizes tend to be small due to the low prevalance of these disorders.

AO2

However, conducting research in SLEEP LABS is DESIRABLE for many reasons.

1) Can study the sleep in a controlled environment.

AO2

2) Can gather SCIENTIFIC, QUANTITATIVE DATA which is easy to analyse and can provide information about PHYSIOLOGICAL ACTIVITY during sleep.

Examples of which are POLYSMOGRAPHY and EEG.

Narcolepsy

• http://www.youtube.com/watch?v=3MBCeKn0Oeo narcolepsy 3 mins

•

NARCOLEPSY

• Narcolepsy is a disabling disorder of sleep regulation that AFFECTS THE CONTROL OF WAKE AND SLEEP.

• It may be described as an INTRUSION OF DREAM SLEEP (called REM or rapid eye movement) into the waking state.

• Symptoms generally begin between the ages of 15 and 30.

NARCOLEPSYThe four classic symptoms of the disorder are

EXCESSIVE DAYTIME SLEEPINESS

CATAPLEXY (sudden, brief episodes of muscle weakness or paralysis brought on by strong emotions such as laughter, anger, surprise or anticipation);

SLEEP PARALYSIS(paralysis upon falling asleep or waking up);

HYPNAGOGIC HALLUCINATION(vivid dreamlike images that occur at sleep onset).

NARCOLEPSY (AO1)Honda et al (1983)• Linked to a mutation in the immune system• Increase of one type of HLA in narcoleptics• HLA molecules found on the surface of white blood cells and

coordinate the immune response

• AO2• HLA variant most commonly found in narcoleptics is not found

in all narcoleptics and is also found in non-narcoleptic, so t cannot be the only explanation (Mignot et al 1997)

NARCOLEPSY (AO1)THANICKAL et al (2000)

Due to MUTATION of the GENE which codes for RECEPTORS for the NEUROTRANSMITTER, HYPOCRETIN (or Orexin).

Hypocretin receptors are found in the HYPOTHALAMUS (sleep centre)

Thought to be involved in WAKEFULNESS.

Showed that there is an 85-95% reduction of HYPOCRETIN RECEPTORS in NARCOLEPTIC HUMANS. (AO2 - SCIENTIFIC MEASUREMENT) – PET SCANS

NARCOLEPSY (AO2)Nishino et al (2000)• Narcoleptics had lower levels of hypocretin in cerebrospinal

fluid• However this is unlikely to be genetic because narcolepsy

doesn’t run in families .• Reduction in hypocretin may be due to brain injury, infection

diet, stress or an immune system problem (explaining the HLA link) – Mignot 2000.

NARCOLEPSY

4 NARCOLEPTICS BRAINS compared to 12 NORMAL BRAINS. (AO2 - Small sample)

AO2 - Scientific measurement of BRAIN STRUCTURE (Scanning)

Gained QUALITATIVE DATA (A02 - can analyse)

Genetic BASIS for NARCOLEPSY?

Guilleminault et al (1989) – First degree relatives have a 40-FOLD CHANCE of inheriting NARCOLEPSY.

AO2- DETERMINISTIC – Narcolepsy is predetermined, cannot be address. THERE IS EVIDENCE ON THE CONTRARY of the genetic argument…..

Contradicted by…..

MIGNOT (1998)

Even in MONOZYGOTIC TWINS where one has NARCOLEPSY, the second is only effected 25% of the time.

THIS MAKE THE GENETIC EXPLANATION REDUCTIONIST (A02).

Honda and Matsuki (1990) – environmentally influenced, not just genetic.

MIGNOT et al

Used CANINE DOGS (anthropomorphic)

SCIENTIFIC MEASUREMENT of BRAIN STRUCTURE.

Mutation of gene that codes for HYPOCRETIN RECEPTOR in the HYPOTHALAMUS

AO2 - The breeding of dogs in order to study NARCOLEPSY –ethical?

Sleep Walking

• Most common in children – 20% children, 3% adults

• Only occurs during NREM/SWS sleep• Related to Night Terrors• Sleep walker not conscious and later has no

knowledge of events during sleep walking

Explanations of Sleep Walking (AO1)

• Incomplete Arousal• EEGs show mix of Delta waves (typical of

SWS) and beta waves (waking state)• Likely to be genetic

Explanations of Sleep Walking (AO1)

• Undeveloped GABA system• Children more likely to sleepwalk• GABA should inhibit motor neurons, but if

the system doesn’t work properly, sleepwalking occurs.

• Oliviero(2007) found adults who sleepwalk have underdeveloped systems

Explanations of Sleep Walking (AO2)

• Diathesis-stress model• Broughton (1968) sleepwalking in first-

degree relatives is 10+ times as common as general population

• Lecendreux et al (2003) 50% concordance rate in twins.

• Stress may be environmental factors like frequent awakenings.