Karen Redhead & Sarah Barclay Sleep Karen Redhead & Sarah Barclay

What is Sleep... and why do we do it? A natural and healthy, but temporary and periodical, suspension of the functions of organs of sense.

Why do we sleep? Theories are Sleep has a restorative function. Why sleep at all? It seems like a big waste of time. Think of all you could be doing if you did not sleep. Theories are Sleep has a restorative function. Sleep has an adaptive function. Memory What happens if we don’t sleep?

Sleep studies Electro encephalograph- EEG Look at ‘Brain waves’ Stages of sleep - Stage 1 - Stage 2 - Stage 3 - Stage 4 - REM

EEG – electroencephalograph The 10-20 International placement system is used to measure the locations of electrodes By placing electrodes in different positions it is possible to detect abnormalities in different areas of the brain The areas that are looked at are - Frontal – working memory, executive functioning, personality, motor function, speech production - Temporal – Auditory processing, language comprehension, long-term memory - Occipital – Primary visual processing - Parietal – Sensory processing, spatial reasoning

Relaxed Stage Wake (eyes open) EEG low voltage, mixed frequency activity Alpha waves 8-13Hz EOG Voluntary control of the eyes blinks observed Slow eye movements, rolling eyes, observed when drowsy EMG Relatively high voluntary movement

Relaxed Stage Wake (eyes closed) EEG rhythmic activity prominent in the occipitals Alpha waves, 8-13Hz EOG There is voluntary control of the eyes Slow eye movements, rolling eyes, observed when drowsy EMG Relatively high voltage voluntary movement

Stage 1 EEG EOG EMG Relatively low voltage Mixed frequency Theta waves (3-7Hz) <50% alpha (8-13Hz) Vertex sharp waves EOG Slow eye movements EMG Tonic Activity May be slightly decreased from wake

Stage 2 EEG EOG EMG Relatively low voltage, mixed frequency Sleep spindles observed K-complexes observed EOG Occasionally slow eye movements (observed near sleep onset) EMG Tonic activity Low voltage

Stage 3 EEG > 20 but < 50% high amplitude Delta waves (<2Hz) Observed maximally in the frontal region May observe sleep spindles and K-complexes EOG No eye movements Usually picks up EEG activity EMG Tonic activity Low voltage

Stage 4 EEG EOG EMG > 50% Delta waves, 2hz Can observed sleep spindles K-complexes may be present but hard to detect among high voltage waves EOG No eye movements Usually pics up EEG activity EMG Tonic activity Low voltage

REM EEG EOG EMG Relatively low voltage mixed frequency Often resembles Stage 1 Occasional “sawtooth” waves usually in conjunction with REMs Alpha can be present but usually 1-2 Hz slower than during wakefulness EOG Phasic Rapid Eye Movements EMG Tonic suppression phasic twitches, usually occur with REMs

Activity There are 4 people one in - REM- eye movements, relaxed chin - Stage 4- slow brain waves with big amplitude and low frequency - Stage 2- EEG-k- complexes and spindles - Awake- fast brain waves with low amplitude and high frequency

Universal Colour Hypnogram Normal Sleep Universal Colour Hypnogram Yellow = Stage 1 Green = Stage 2 Teal = Stage 3 Dark Blue = Stage 4 Red = REM

Normal Sleep Patterns 1st cycle is approx 100- 120mins, cycles then occur approx 90- 100 mins As the night progresses the amount of SWS is reduced and REM sleep increased

Sleep Deprivation Can be chronic- reduced sleep over a long period , or acute- no sleep last night Affects include-aching muscles, confusion, memory lapses or loss, depression, hallucinations, hand tremors, headaches, irratability, obesity, yawning, temper tantrums in children, high blood pressure, increased stress hormones, increased risk of diabetes, symptoms similar to ADHD.

Sleep deprivation affects Mood- linked to depression Weight- linked to weight gain- obesity Memory- impaired memory Brain function- reduced activity in temporal lobe Ability- driving while sleep deprived has been shown to be equivalent to driving drunk( 0.08- 0.1 alcohol limit) Total sleep deprivation results in death

Affect of sleep deprivation on memory Affects routine applications more than complex tasks Tested by PVT (psychomotor vigilance task)- press a button in response to random light In chronic sleep deprivation results are not predictable by peoples perception of impairment

Rebound sleep After a period of sleep deprivation experience rebound SWS and REM sleep Show a significant increase in slow wave sleep and REM sleep Decrease in stage 2 sleep Recover from sleep deprivation in a few nights

REM Rebound hypnogram

Delayed Sleep Onset Hypnogram

Adolescent sleep Experience delayed sleep phase syndrome due to the release of melatonin later this is compounded by social factors and results in: Feel tired later and have trouble waking in the morning Often are sleep deprived and sleep on weekends to catch up on sleep

Tips to try and help Stay away from caffeine and nicotine after noon. Also avoid or limit alcohol which can disrupt sleep. Avoid using a computer before bed. Avoid trying to sleep with a computer or TV flickering in the room. Avoid bright light in the evening, but open blinds or turn on lights as soon as the morning alarm goes off. Sleep in on the weekend, but no more than 2 or 3 hours later than their usual.