New Research on Sleep Deprivation

Posted by Admin on March 30, 2011
New research is looking into ways to reverse the effects of sleep deprivation. The effect of sleep deprivation on cognitive function is well documented even though the underlying reasons are not well understood.

The impact of sleep deprivation on our mental function includes:

Auditory function - The auditory attention of sleep-deprived individuals is affected as the total amount of sleep-deprivation increases.  

Divided attention – The ability to divide our attention decreases dramatically with lack of sleep. Our inability to divide attention can impact our ability to disregard irrelevant information during attention-related tasks.

Exogenous versus endogenous attention – lack of sleep impacts our ability to react to exogenous information – information coming from outside ourselves. As a result we are more often prone to be aware of internal bodily perceptions – both physical and mental.

Supervisory attention – The ability to shift attention quickly and react to responses is affected by sleep deprivation. Often called “supervisor attention” this ability allows us to manage a set of parameters needing limited focus and time and then shift to a new set. It is important in managing a larger scale projects.

Visuospatial attention – Our ability to recognize our position in space, accurately judging distance and relationship between objects is diminished by sleep deprivation.

Executive function – Executive function includes a range of coordinated cognitive skills. These includes decision making, risk assessment, error correction and planning. Each by itself is an important skill set. Yet under the duress of lost sleep the various skills suffer in themselves and are more difficult to coordinate.

Memory – Both short and long term memory are increasing affected by the loss of sleep.

So given all these detrimental effects of the loss of sleep why do many adolescents and young adults harbor a desire to skip sleep in favor of getting more from daily life.

Research  from Wake Forest University School of Medicine now sheds some light on the physiology behind the desire to sleep less.

Orexin-A, has been shown to reverse the effects of sleep deprivation on cognitive performance in monkeys. The research opens the door to a range of new therapeutic modalities, from helping patients with sleep disorders to aiding those people who are employed on varying work shifts. These also include military personnel and other occupations where sleep patterns are disturbed.

Orexin-A or hypocretin-1 is a naturally occurring brain peptide. It was shown that when administered to monkeys in the laboratory it could reverse the effects of sleep deprivation. The primates had been tested at natural alertness, after sleep deprivation and again after application of Orexin-A.

Though normally Orexin-A is secreted by a small number or neurons, it affects many brain regions during the day. People who have normal amounts of orexin-A are able to maintain wakefulness. When people or animals are sleep-deprived, the brain attempts to produce more orexin-A but often not enough to achieve alertness past the normal daily cycle.

During the study, monkeys were kept awake for 30-36 hours until the normal testing time the next day. They then performed their trained tasks with several cognitive problems that varied in difficulty. Researchers observed their performance to be significantly impaired. However, when the sleep deprived monkeys were administered orexin-A either intravenously or through a nasal spray immediately before testing, their cognitive skills improved to normal levels.

Researchers also observed that orexin-a, at moderate dose levels, had no effect on performance if the animals were not sleep-deprived. It is unclear how this peptide spray would effect someone suffering from extreme sleep deprivation.

The military has looked at the issues of sleep deprivation at great length. The evidence is laid out in "Human Performance," a report commissioned by the Pentagon's Office of Defense Research and Engineering. The report shows to what extent sleep deprivation degrades performance and endangers the lives of military personnel in all aspects of the filed – from combat missions to more mundane activities.

The document, issued by a defense science advisory group known as JASON, was originally published in 2008.

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