Elsevier

Sleep Medicine Reviews

Volume 10, Issue 5, October 2006, Pages 323-337
Sleep Medicine Reviews

CLINICAL REVIEW
Sleep loss, learning capacity and academic performance

https://doi.org/10.1016/j.smrv.2005.11.001Get rights and content

Summary

At a time when several studies have highlighted the relationship between sleep, learning and memory processes, an in-depth analysis of the effects of sleep deprivation on student learning ability and academic performance would appear to be essential. Most studies have been naturalistic correlative investigations, where sleep schedules were correlated with school and academic achievement. Nonetheless, some authors were able to actively manipulate sleep in order to observe neurocognitive and behavioral consequences, such as learning, memory capacity and school performance. The findings strongly suggest that: (a) students of different education levels (from school to university) are chronically sleep deprived or suffer from poor sleep quality and consequent daytime sleepiness; (b) sleep quality and quantity are closely related to student learning capacity and academic performance; (c) sleep loss is frequently associated with poor declarative and procedural learning in students; (d) studies in which sleep was actively restricted or optimized showed, respectively, a worsening and an improvement in neurocognitive and academic performance. These results may been related to the specific involvement of the prefrontal cortex (PFC) in vulnerability to sleep loss. Most methodological limitations are discussed and some future research goals are suggested.

Introduction

Sleep is an active, repetitive and reversible behaviour serving several different functions, such as repair and growth, learning or memory consolidation, and restorative processes: all these occur throughout the brain and the body.1, 2 Thus, during sleep behavioural, physiological and neurocognitive processes occur: these very processes are susceptible to be impaired by the absence of sleep.

Sleep loss is, in fact, one of the most striking problems of modern society.3 Very often, to cope with our many daily interests, we prefer to sacrifice some sleep time, in the hope that this will not induce dangerous effects but will enable us to carry out several other activities. Unfortunately, this is not true and sleep deprivation has various consequences, such as sleepiness and impairments in neurocognitive and psychomotor performance.4, 5 More specifically, in their classic meta-analysis, Pilcher and Huffcut4 claimed that sleep-deprived individuals functioned at a level that is comparable with the ninth percentile of non-sleep-deprived subjects. These decrements in neurobehavioural functioning after sleep restriction or deprivation are well known and common to all people6, 7 even though some individual differences in vulnerability to sleep loss have been shown.8

The last few years have seen an increasing literature on the relationship between sleep, memory and learning capacity (e.g. Ref.9). Recent findings have shown that sleep plays an important role in learning processes and memory consolidation,10, 11 although no direct relationships were found between different kinds of memory, such as procedural or declarative memory, and different sleep stages, such as REM or NREM sleep.12 These studies clearly show that sleep deprivation can impair learning and memory for both motor procedural (e.g. Ref.10) and declarative memory systems (e.g. Ref.13).

It is well known that the integrity of learning and memory processes are fundamental in school achievement and academic performance, particularly in individuals like children and adolescents who are in a particular developmental phase.14, 15, 16, 17, 18 At this stage in life, adolescents suffer from increasing school, family and social pressure and from an environmentally induced delay of sleep timing,19, 20, 21 together with changes of intrinsic regulatory (both circadian and homeostatic) processes.22 Taken together, these altered sleep patterns lead to a marked increase in sleepiness23 that usually facilitates cognitive, emotional, behavioural and academic failure.22 Surprisingly, not much data exists regarding the specific effects of inadequate sleep and sleepiness on daytime functioning in children.17 Nevertheless, some experimental evidence reinforces the common belief that disrupted or poor sleep is usually followed by inefficient daytime behaviour and variability in performance. Within these activities, academic performance and/or school achievement should be carefully taken into consideration. As recently pointed out in some literature reviews,24, 25, 26 learning abilities and consequent academic performance are particularly dependent on sleep patterns and sleepiness levels. These impairments in neurocognitive functioning can be observed in several kinds of learners: from school to university students, so that the consequent ability to learn from lessons or from practical activities, such as laboratory work, very often proves to be drastically reduced.

The aim of this review is to focus on the effects of sleep deprivation/fragmentation on ‘day-after’ learning capacity and academic performance. In order to discuss these issues, we will briefly introduce the most recent findings on the relationships between sleep and learning-memory processes. Then, we will turn our attention to the studies showing the relationship between sleep patterns and schedules on academic performance and learning. Finally, we will discuss studies investigating the effects of induced sleep loss on academic performance and neurobehavioural functioning, with particular attention to learning capacity.

Section snippets

The relationship between sleep and learning-memory processes

For almost a century, several studies showed the beneficial effects of sleep on memory functioning in animals and humans for different types of learning materials.9, 27, 28 Recent studies in molecular genetics, neurophysiology, and cognitive and behavioural neuroscience have strengthened the idea that sleep may play an important role in learning and memory, although the extent of this role remains hotly debated.29 In fact, there is still poor understanding as regards which aspects of memory

Sleep patterns/schedules and academic performance

As seen in the previous section, sleep has a relevant facilitating role in learning and memory processes. Conversely, sleep deprivation and/or fragmentation usually impairs these functions. In the following, we will review the most relevant contributions in the literature investigating the effects of sleep patterns and schedules on academic performance of school and university students. It should be stressed that most of these studies correlated sleep-wake patterns with subjective (self- or

Effects of imposed sleep loss on learning and academic performance

Results from studies investigating the effects of different sleep patterns and schedules on academic performance showed that students who sleep poorly, with an elevated sleep fragmentation (i.e., reduced sleep quality), with later bedtimes and early awakenings, usually tend to offer a decreased academic performance and a reduced neurobehavioural functioning.14, 25, 26 However, the studies seen so far are only ‘naturalistic’ correlative ones: in this section we shall more deeply review those

Conclusions

The studies discussed here allow us to draw some conclusions. As a first observation, regardless of the theoretical framework adopted (dual process hypothesis or sequential processing hypothesis), both REM and NREM sleep seem necessary for learning and memory: thus, for an efficient consolidation of both (declarative) knowledge and (procedural) skills, the worst risk is sleep loss or fragmentation.

Moreover, it was shown that an increasing daytime sleepiness, as a consequence of poor sleep

Acknowledgements

We wish to thank Giancarlo La Camera, Ph.D. (NIH, Bethesda, USA) and Caterina Cinel, Ph.D. (University of Essex, UK) for their invaluable help in collecting some of the bibliographic material.

References (114)

  • G. Ficca et al.

    Morning recall of verbal material depends on prior sleep organization

    Behav Brain Res

    (2000)
  • M. Walker et al.

    Practice with sleep makes perfect: sleep dependent motor skill learning

    Neuron

    (2002)
  • W. Plihal et al.

    Dexamethasone blocks sleep induced improvement of declarative memory

    Psychoneuroendocrinol

    (1999)
  • J.J. Pilcher et al.

    Sleep quality versus sleep quantity: relationships between sleep and measures of health, well-being and sleepiness in college students

    J Psychosom Res

    (1997)
  • M.R. Steenari et al.

    Working memory and sleep in 6- to 13-year-old schoolchildren

    J Am Acad Child Adolesc Psychiatry

    (2003)
  • P.W. Mercer et al.

    Differences in reported sleep need among adolescents

    J Adol Health

    (1998)
  • K. Jones et al.

    Frontal lobe function, sleep loss and fragmented sleep

    Sleep Med Rev

    (2001)
  • F. Salcedo Aguilar et al.

    Hábitos de sueño y problemas relacionados con el sueño en adolescentes: relación con el rendimiento escolar

    Aten Primaria

    (2005)
  • M. Blaiss

    Current concepts and therapeutic strategies for allergic rhinitis in school-age children

    Clin Ther

    (2004)
  • Y. Harrison et al.

    One night of sleep loss impairs innovative thinking and flexible decision making

    Organ Behav Hum Decis Process

    (1999)
  • J.M. Krueger et al.

    Sleep function

    Front Biosci

    (2003)
  • J.H. Benington

    Sleep homeostasis and the function of sleep

    Sleep

    (2000)
  • M.H. Bonnet

    Sleep Deprivation

  • J.J. Pilcher et al.

    Effects of sleep deprivation on performance: a meta-analysis

    Sleep

    (1996)
  • Y. Harrison et al.

    The impact of sleep deprivation on decision making: a review

    J Exp Psychol Appl

    (2000)
  • H.P. Van Dongen et al.

    The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation

    Sleep

    (2003)
  • J.S. Durmer et al.

    Neurocognitive consequences of sleep deprivation

    Semin Neurol

    (2005)
  • H.P. Van Dongen et al.

    Systematic interindividual differences in neurobehavioral impairment from sleep loss: evidence of trait-like differential vulnerability

    Sleep

    (2004)
  • P. Peigneux et al.

    Sleeping brain, learning brain. The role of sleep for memory systems

    Neuroreport

    (2001)
  • J.A. Hobson et al.

    The cognitive neuroscience of sleep:neuronal systems, counsciousness and learning

    Nature Rev Neurosci

    (2002)
  • G. Rauchs et al.

    The relationships between memory systems and sleep stages

    J Sleep Res

    (2005)
  • S. Gais et al.

    Declarative memory consolidation: mechanisms acting during human sleep

    Learn Mem

    (2004)
  • M.A. Carskadon

    Patterns of sleep and sleepiness in adolescents

    Pediatrician

    (1990)
  • A.R. Wolfson et al.

    Sleep schedules and daytime functioning in adolescents

    Child Dev

    (1998)
  • M.A. Carskadon et al.

    Association between puberty and delayed phase preference

    Sleep

    (1993)
  • S.F. Gau et al.

    The transition of sleep-wake patterns in early adolescence

    Sleep

    (2003)
  • M.A. Carskadon et al.

    Regulation of adolescent sleep: implications for behavior

    Ann N Y Acad Sci

    (2004)
  • M.A. Carskadon et al.

    Regulation of sleepiness in adolescents: update, insights, and speculation

    Sleep

    (2002)
  • J.S. Samkoff et al.

    A review of studies concerning effects of sleep deprivation and fatigue on residents’ performance

    Acad Med

    (1991)
  • J. Jenkins et al.

    Oblivescence during sleep and waking

    Amer J Psychol

    (1924)
  • J. Siegel

    The REM sleep-memory consolidation

    Science

    (2001)
  • J. Born et al.

    Roles of early and late nocturnal sleep for the consolidation of human memories

  • L. Squire

    Declarative and nondeclarative memory: multiple brain systems supporting learning and memory

    J Cogn Neurosci

    (1992)
  • W. Plihal et al.

    Effect of early and late nocturnal sleep on declarative and procedural memory

    J Cogn Neurosci

    (1997)
  • R. Stickgold

    Human studies of sleep and off-line memory processing

  • A. Karni et al.

    Dependence on REM sleep of overnight improvement of a perceptual skill

    Science

    (1994)
  • R. Stickgold et al.

    Visual discrimination learning requires sleep after training

    Nat Neurosci

    (2000)
  • S. Gais et al.

    Early sleep triggers memory for early visual discrimination skills

    Nat Neurosci

    (2000)
  • R. Stickgold et al.

    Visual discrimination task improvement: A multi-step process occurring during sleep

    J Cogn Neurosci

    (2000)
  • S. Fischer et al.

    Sleep forms memory for finger skills

    PNAS

    (2002)
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