Sleep deprivation studies
These are interesting in their own right, but from a
practical point of view can be used:
evidence for the restoration theory of sleep
essay on the methods used in the study of sleep
example of disruption of biological rhythms
Total sleep deprivation
These studies tend to be carried out on student participants
at various universities, for example Loughborough and Edinburgh in the
UK. There are also the two infamous cases of sleep deprivation for the
purposes of charity and notoriety in the Guinness book of records.
Peter Tripp spent 201 hours and 10 minutes awake, much of it sitting in
a glass booth in Times Square, spinning records and bantering into his
microphone three hours a day.
When Mr. Tripp
began to fall asleep, nurses shook him; doctors joked with him, played
games with him and gave him tests to take. After a few days, he began to
hallucinate, seeing cobwebs, mice, kittens; looking through drawers for
money that wasn't there; insisting that a technician had dropped a hot
electrode into his shoe.
His last 66 hours
awake were spent under the influence of drugs administered by the
doctors and scientists observing him. Asked at the end of his stunt what
he wanted the most, Mr. Tripp said, not surprisingly, that he wanted to
sleep, which he then did for 13 hours and 13 minutes.
Mr. Tripp's career
was indelibly tarnished by the 1960 payola scandal, in which he and
several other disc jockeys and radio station employees were indicted on
charges of accepting money from record companies in exchange for playing
their records. Tripp later blamed his involvement, at least in part, to
his sleep deprivation.
during his wakeathon attempt
Randy Gardner (1965) stayed awake for a record breaking 11 nights as part
of a school science project!!!. He reported blurred vision, slurred
speech, mild paranoia in which he began to believe that the researchers
watching him thought he was stupid. When Randy was allowed to sleep he
did so for 14 hours and 40 minutes on the first night and two hours longer
than usual on the next two nights. So, despite losing about 90 hours
sleep he only made up about 11. However, he did catch up on a
disproportionate amount of his lost stage 4 (68%) and REM sleep (53%)
suggesting that these are the vital stages. There were estimated to be 67
hours of sleep that he did not make up. Despite his exploits he suffered
no long term consequences.
In fact Randy
never made it into the Guinness Book of Records because,
according to Wiki, a month later Toimi Soini of Finland beat the
record by a few hours. (Why so little about this effort is
known I’m not sure). In 1989 the record was removed from the
book because of fears that it would encourage others to risk
their health by attempting to beat it. Earlier this
year, Tony Wright of Penzance stayed awake longer than Gardner
but unaware of Toimi Soini’s record fell just short of the last
Guinness World Record
Accounts of the degree to which Gardner suffered during the
attempt vary. The official report by Dement paints a picture of little
or no cognitive disfunction. On the tenth day of his ordeal Dement
interviewed Gardner and then took him for a game of pinball, which
Gardner won. However,
J. Ross a commander of the U.S. Navy Medical Neuropsychiatric Research
Unit in San Diego, who was called in by Gardner’s parents, describes a
more serious loss of ability.
first few days these included problems focusing, inability to repeat
simple tongue twisters and moodiness. By day four there was memory loss
and the first hallucination, he imagined that a street light was a
person. Later in the same day he had a delusional episode, imagining
himself to be a famous black footballer!
end of the first week speech had slowed and become slurred and he was
having problems…. *
last two days his loss of cognitive ability was far more marked than
Dement suggests. When asked to count backwards from 100 in evens he
stopped at 65. When asked why he said he couldn’t remember what he was
supposed to be doing. He became paranoid and his speech was slow and
It is difficult to generalise to the general population with
case studies like this that by definition have a very small sample size,
particularly with such different findings between studies. Most
research since has backed this up. Greatest impairment appears to be in
boring tasks and those requiring close attention. Sleep deprived radar
operators in the war would miss enemy planes appearing on the screen.
Tired car and lorry drivers may have accidents following a few seconds
of micro sleep in which consciousness fades and the eyes de-focus.
In cases of fatal familial insomnia, people sleep normally
until middle age when they suddenly stop. Death is usually within two
years! Lugaressi et al (1986) reported the case of a man with brain
damage who as a result slept very little. He was unable to live a
normal life and eventually died as a result!
Larger studies on
The main study is the meta-analysis carried out by Huber-Wiedman
who collated the data from a large number of sleep deprivation studies.
The findings are summarised in the table:
Urge to sleep especially between 2 and 4 in the morning
Cognitive tasks requiring concentration are seriously
impaired, especially if they are repetitive or boring.
Periods of micro sleep are unavoidable and the volunteer
becomes irritable and confused. The ‘hat phenomenon’ occurs.
Still irritable and confused and may also become
Person becomes depersonalised with a loss of self
identity. This is referred to as ‘sleep deprivation psychosis.’
Webb & Bonnett (1978) used a different method of sleep
deprivation. They got their participants to gradually reduce their
sleep by 2 hours. Participants reported no ill effects. In a follow up
they got them to reduce sleep to only 4 hours per night, again without
Even with larger
sample sizes such as this study there are still serious issues with the
methodology. The participants are under tightly controlled conditions
and know that they’re being watch 24 hours a day. This will involve
massive demand characteristics and presumably with people that have
volunteered to remain awake for long periods they will probably view it
as a competition. This will not only create a level of stress but also
significantly increase motivation.
Dement himself admits that his own observations of participants are a
big source of bias due to his own expectations when observing
Overall evaluation of human deprivation studies
On the face of it they do appear to support the restoration
theory. However, with some of the studies it could be stress resulting
from deprivation rather than deprivation per se that caused the
effects observed. Hence we have problems with cause and effect
Dement’s work was carried out in sleep laboratories and this
in itself may have caused disruption to the night’s sleep. In the case
of Webb & Bonnet there is also the issue of social desirability bias
with participants just wanting to look psychologically tough.
The concept of total sleep deprivation is very artificial.
It is exceptionally rare for people in real life to go completely
without sleep for any length of time. As a result the studies lack
ecological validity, more so than studies of partial deprivation. Betty
Schwartz in the USA studies cases of supposed total insomnia, in which
patients claim that they never sleep. However, when tested under lab
conditions it is usually found that they have quite a good nights sleep,
but without realising it.
One finding that does appear common to animal studies and
human case studies is that total sleep deprivation is fatal and as yet
we don’t understand why!
human studies participants are aware that they are being observed and
this may well affect their behaviour. Bentley (2000) says that Dement
recognised this as being an issue in his 1960 study.
Animal studies (total sleep deprivation)
Rechtschaffen et al (1983) placed rats on a disc over
water. Each time that its EEG suggested it was falling asleep the disc
would rotate forcing the rat to walk to stay out of the water. A second
rat was used as a control. This had to do the same amount of walking
but was able to sleep when the other rat was awake. The experimental
rats started to lose weight after a week due to increased metabolic rate
started to eat more. Despite this, the weight loss continued and after
about three weeks the rats started to die. After 33 days all the sleep
deprived rats were dead.
Partial sleep deprivation
In these procedures volunteers are deprived of part of their
night’s sleep, i.e. deprived of REM or deprived of NREM sleep only.
Dement (1960) deprived volunteers of either REM or NREM
sleep and observed the consequences. He found that REM deprivation was
most dramatic with participants becoming more aggressive and having very
poor concentration. He also reported REM rebound effects, in which
participants would try and catch up on lost REM sleep. For example
going straight into REM when allowed to go back to sleep. By the
seventh night Dement reported that participants were averaging 26
attempts per night to enter REM. After the procedure when they were
allowed an uninterrupted nights sleep they spent much longer in REM.
This is similar to the results reported following the Randy Gardner
study and again reinforces the apparent importance of REM sleep.
In practice partial sleep deprivation is not possible over
any period of time since participants need to be woken so often it
quickly deteriorates into total sleep deprivation.
Jouvet (1967) used the flower pot technique to deprive cats
of REM sleep. They would be placed on an upturned flower pot in a tank
of water. This allowed them to sleep, but when they entered REM and lost
muscle tone they would fall into the water. They then climb back onto
the flowerpot renter the stages and fall back in once REM is reached.
In fact after a number of trials the cats become conditioned. On
reaching REM they wake up before falling into the water on many of the
trials. The study again is very unethical and cruel. On average the
cats survive for 35 days.
I couldn’t find a
picture of Jouvet’s cats on a flowerpot, however, this is a rat on a
flowerpot in a bowl of water.
of animal deprivation studies
animal studies there are clearly issues of generalising to humans.
animal studies are particularly cruel since unlike humans the animals
have no idea that the experiment will eventually end!
Conclusions on sleep function (courtesy of Dwyer and
The evolutionary theories of sleep are unable to explain why
sleep deprivation has such adverse effects whereas theory restoration
can. However, it is clear that sleep is essential for survival and this
is in agreement with the evolutionary theory’s adaptive value of sleep.
Modern ideas assume that restoration does in itself serve an adaptive
function so both evolutionary and restoration theories may be relevant.
Furthermore, sleep may serve other useful purposes as yet not
considered. One of these could be to allow us to dream. As
Shakespeare put it; “to sleep perchance to dream.”