Elsevier

Brain and Cognition

Volume 60, Issue 1, February 2006, Pages 76-87
Brain and Cognition

Effects of sleep deprivation on Color-Word, Emotional, and Specific Stroop interference and on self-reported anxiety

https://doi.org/10.1016/j.bandc.2005.10.001Get rights and content

Abstract

The aim of this study was principally to assess the impact of sleep deprivation on interference performance in short Stroop tasks (Color-Word, Emotional, and Specific) and on subjective anxiety. Subjective sleepiness and performance on a psychomotor sustained attention task were also investigated to validate our protocol of sleep deprivation. Twelve healthy young subjects were tested at four-hourly intervals through a 36-h period of wakefulness under a constant routine protocol. Analyses of variance for repeated measurements revealed that self-assessment of sleepiness on a visual analogue scale as well as mean reaction time performance on the sustained attention task, both for the first minute and for 10 min of testing, were worsened by sleep deprivation. Analyses revealed an increase in self-reported anxiety scores on the STAI questionnaire but did not reveal any significant effect after sleep deprivation either on indexes of interference or on accuracy in Stroop tasks. However, analyses showed sensitivity to circadian effect on verbal reaction times in the threat-related (Emotional) and sleep-related (Specific) Stroop tasks. We concluded that 36 h of prolonged wakefulness affect self-reported anxiety and Emotional Stroop task resulting in a cognitive slowing. Moreover, total sleep deprivation does not affect interference control in any of the three short Stroop tasks.

Introduction

Sleep deprivation is known to increase degree of sleepiness (Carskadon and Dement, 1979, Gillberg et al., 1994) and to insidiously affect cognitive performance.

Wilkinson (1964) recommended the use of relatively long duration vigilance tasks (i.e., 30–60 min) to observe sleep deprivation effects. However, Lisper and Kjellberg (1972) showed a slowing in performance on a 10-min high signal rate auditory RT task and an interaction with task-duration with one night of sleep deprivation. Nevertheless, Dinges and Kribbs (1991) observed that this misconception for the need of long-duration tasks to show the effects of sleep loss on performance lasted in the literature for decades, whereas short cognitive tasks are sensitive to sleep loss (Dinges, 1992).

Dinges and Kribbs (1991) reviewed evidence for sleep loss leading above all to performance lapsing, cognitive slowing, and time-on-task decrements. The predominant explanation in the past 45 years for sleep loss-related performance decrements has been the “lapse hypothesis” (Williams, Lubin, & Goodnow, 1959). A sleepy participant is thought to perform normally until a microsleep occurs, causing the occurrence of a lapse (i.e., reaction time greater than twice the subject’s baseline mean or no response when extreme sleepiness) whose frequency and duration increase as a function of sleep deprivation. However, the concept of lapsing cannot fully explain cognitive impairment induced by sleep loss. Notably, the variability in PVT performance reflects a combination of normal timely responses, errors of omission (i.e., lapses), and errors of commission (i.e., responding when no stimulus is present). The “state instability” hypothesis (Doran, Van Dongen, & Dinges, 2001) posits that as sleep loss progresses, variability in performance increases in a manner reflecting the interaction of the homeostatic drive for sleep and the endogenous circadian drive for wakefulness, and the compensatory effort exerted by subjects to perform. The state instability hypothesis predicts that normal responding after substantial sleep loss cannot be sustained over time, even in the face of compensatory effort, due to the chronic intrusion of sleep initiation processes into wakefulness. Mean simple reaction time performance on a 10-min psychomotor vigilance task (PVT) is considered as a highly sensitive measure to sleep loss (Dinges et al., 1997, Doran et al., 2001, Jewett et al., 1999, Philip et al., 2003, Philip et al., 2004, Sagaspe et al., 2003, Van Dongen et al., 2003).

Concerning higher cognitive functions, executive tasks are likely to be sensitive to sleep loss. Executive functions notably include the ability to plan and coordinate wilful action in the face of alternatives, to monitor and update action as necessary and to suppress distracting material by focusing attention on the relevant information (i.e., inhibition). Sensitivity to total sleep deprivation of stimulating and short-duration executive tasks such as planning, decision-making, judgment, reasoning, speech, and divergent thinking (i.e., skills requiring spontaneity, creativity, and flexibility) involving the prefrontal cortex (PFC) has been reported (Harrison and Horne, 2000, Jones and Harrison, 2001). For instance, neuropsychological tests such as the “Tower of London Test” (Horne, 1988, Morris et al., 1993), word fluency tasks (Harrison and Horne, 1997, Harrison and Horne, 1998, Harrison et al., 2000, Horne, 1988, Morris et al., 1993), the “Haylings completion sentence test” (Harrison & Horne, 1998), and the “Stroop task” (McCarthy & Waters, 1997) are sensitive to one night of sleep deprivation in young healthy participants. Moreover, Lingenfelser et al. (1994) showed significant impairment on the Stroop task after sleep deprivation. However, confounding factors such as fatigue, stress, and different amounts of sleep debt might have affected performance in their young hospital doctor subjects.

On the other hand, some studies do not present concordant results with the impact of sleep deprivation on executive functions. Binks, Waters, and Hurry (1999) found no effect of short-term sleep deprivation on a Wisconsin Card Sorting Test, a word fluency task and a Stroop task, suggesting that sleep deprivation does not selectively impair prefrontal functioning, notably the cognitive flexibility and the capacity to shift from one response set to another. Moreover, Fallone, Acebo, Arnedt, Seifer, and Carskadon (2001) found that sleep restriction was not associated with impaired performance of healthy children and adolescents performing inhibition tasks. Finally, Sagaspe et al. (2003) concluded that a 36-h period of prolonged wakefulness in young adults does not significantly affect inhibition processes in a short executive task of random letters generation.

One of the most widely used neuropsychological tests to study attention and notably its inhibitory processes is the Stroop Color-Word test (MacLeod, 1991, Stroop, 1935, Vendrell et al., 1995). The Stroop task consists of two conditions. In the first, a subject is required to name the color of the ink in which patches or strings of letters are printed (i.e., xxxx). This measure is used to obtain a baseline value for individuals to name colors. In the second, the subject is required to name the color of the ink in which a word (a color name) is printed (i.e., the word “green” written in blue ink). Subjects find the incongruity of color names distracting because the word meaning interferes with the speed of color naming. The longer the color naming, the larger the conflict between the two stimuli dimensions. This has been called “Stroop interference.” This task has been used extensively to study limitations in the ability to fully suppress the influence of a dominant source of information, such as automatic word reading. Therefore, the magnitude of the Stroop interference has been used as an indicator of the efficiency of the inhibitory function. Because of the controversy related to divergent findings, we decided to conduct a controlled study on the effects of sleep deprivation on inhibition with a Stroop Color-Word task.

Moreover, few experiments have been conducted on the effects of sleep deprivation on anxiety. Routine studies determine the effects of sleep deprivation on mood by broadly using the Profile of Mood States (POMS). The POMS questionnaire measures mood on 6 scales: (1) tension–anxiety, (2) depression–dejection, (3) anger–hostility, (4) vigor–activity, (5) fatigue–inertia, and (6) confusion–bewilderment (McNair, Lorr, & Droppleman, 1971). Previous studies on healthy young adults have revealed negative effects of sleep deprivation on emotional measures, globally reflecting a decrease in vigor–activity and an increase in fatigue–inertia, confusion–bewilderment, and tension–anxiety (Brendel et al., 1990, Dinges et al., 1997, Mikulincer et al., 1989, Pilcher and Huffcutt, 1996). The aim of our study was to determine whether sleep deprivation significantly increases state–anxiety measured by STAI (Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983).

A new cognitive approach should investigate the effects of sleep deprivation and anxiety on cognitive tasks implying an emotional component. A modified version of the Stroop Color-Word task is the Emotional Stroop task (Williams, Mathews, & MacLeod, 1996). The emotional variant contains threat-related and neutral words and has been widely used to investigate the association between attentional bias and emotion. This version was created on the hypothesis that words of pictorial stimuli having affective significance can produce interference and tend to capture attention more effectively than do neutral stimuli. In this version there is no response competition as in the classical one. The interference is considered to be the result of other cognitive processes initiated by the semantic content of the word. Anxiety patients present an attentional bias towards threat information. On the Emotional Stroop task, they take longer to name the color of anxiety-related words than neutral control words, and in particular, the kind of words that are related to their specific fear. Interference effects have been demonstrated for anxiety patients (Mathews & MacLeod, 1985), for patients with spider phobia (Watts, McKenna, Sharrock, & Trezise, 1986), etc. For instance, in a study by Watts et al. (1986), two different versions of the Emotional Stroop task were used, one containing words such as fear, death, and grief and another containing stimuli specifically related to the psychopathology presented by the participants (spider-avoidants) such as crawl and hairy. Participants showed a greater interference in color-naming spider words. Nevertheless, similar effects have also been demonstrated in healthy subjects, with regard to personally relevant words referring to their current concerns (Riemann & McNally, 1995). An approach to examine anxiety effects on performance in the Emotional Stroop test is to experimentally induce increased levels of anxiety (Amir et al., 1996, Richards et al., 1992) or to use stressful situations like sleep deprivation. We decided to test the attentional bias in sleep-deprived subjects by using an Emotional Stroop task and a Specific Stroop task. The idea for this modified version with sleep-related words came about from a study with insomniac patients (Lundh, Froeding, Gyllenhammar, & Broman, 1997). We hypothesize that the anxious state induced by sleep deprivation will precipitate attention towards anxiety and sleep-related threat cues.

The present study assesses the impact of one night of sleep deprivation on inhibitory processes and anxiety levels. To do so, we used three different versions of the Stroop tasks (Color-Word, Emotional, and Specific) and a self-measure of anxiety on a 36-h period of constant routine protocol. Self-reported sleepiness measures and the simple reaction time performance on a sustained attention task, which is very sensitive to sleep deprivation according to the literature, were a guarantee of the effectiveness of our protocol.

Section snippets

Participants

Twelve healthy male subjects, ranging in age from 18 to 26 years (mean = 21.5 years, SD = 2.3), were recruited through advertisements around local universities. To eliminate the presence of any sleep or mood disorder in our sample, they completed the French version of the Basic Nordic Sleep Questionnaire (BNSQ) (Partinen & Gislason, 1995) and the Self-report symptoms inventory SCL-90R (Derogatis, Lipman, & Covi, 1973). Subjects showing no evidence of psychopathology (SCL-90R score <60 on the

Subjective sleepiness

The scores for the VAS of sleepiness (Fig. 1) were analysed using a one-way within-subjects ANOVA, with “session” (8H, 12H, 16H, 20H, 24H, 4H, 8H, 12H, and 16H) as factor. A significant main effect of this factor was found [F (8, 88) = 13.722, p < .001]. Mean self-reported sleepiness increased after the night of sleep deprivation from 12H (day 1) to 12H (day 2) (20.66 vs. 50.75) [t (11) = −7.199, p < .001] and from 16H (day 1) to 16H (day 2) (22.16 vs. 47) [t (11) = −4.722, p < .001].

Simple sustained attention task

A two-way repeated

Discussion

This study investigated the impact of one night of total sleep deprivation through a 36-h period under constant routine protocol on interference performance, verbal reaction times and percentage of errors in three short Stroop tasks (Color-Word, Emotional, and Specific) and on subjective state-anxiety levels. Interest was given to subjective sleepiness and to simple sustained attention.

Acknowledgments

The authors gratefully acknowledge the support for this research provided by the CHU of Bordeaux (France) and the Conseil Régional d’Aquitaine.

References (59)

  • Bruchon-Schweitzer, M., & Paulhan, I. (1993). Adaptation française et validation du STAI-Y de C. D. Spielberger. Revue...
  • M.A. Carskadon et al.

    Effects of total sleep loss on sleep tendency

    Perceptual and Motor Skills

    (1979)
  • A. Content et al.

    BRULEX. Une base de données lexicales informatisée pour le français écrit et parlé. BRULEX: A computerized lexical data base for the French language

    L’Année Psychologique

    (1990)
  • C.A. Czeisler et al.

    Exposure to bright light and darkness to treat physiologic maladaptation to night work

    New England Journal of Medicine

    (1990)
  • L.R. Derogatis et al.

    SCL-90: An outpatient psychiatric rating scale-preliminary report

    Psychopharmacology Bulletin

    (1973)
  • D.F. Dinges

    Probing the limits of functional capability: The effects of sleep loss on short-duration tasks

  • D.F. Dinges et al.

    Performing while sleepy: Effects of experimentally-induced sleepiness

  • D.F. Dinges et al.

    Cumulative sleepiness, mood disturbance and psychomotor vigilance performance decrements during a week of sleep restricted to 4–5 hours per night

    Sleep

    (1997)
  • S.M. Doran et al.

    Sustained attention performance during sleep deprivation: Evidence of state instability

    Archives Italiennes de Biologie

    (2001)
  • S.P.A. Drummond et al.

    Increased cerebral response during a divided attention task following sleep deprivation

    Journal of Sleep Research

    (2001)
  • C.L. Dulaney et al.

    Mechanisms underlying reduction in Stroop interference with practice for young and old adults

    Journal of Experimental Psychology: Learning, Memory, and Cognition

    (1994)
  • G. Fallone et al.

    Effects of acute sleep restriction on behavior, sustained attention, and response inhibition in children

    Perceptual and Motor Skills

    (2001)
  • A. Feinstein et al.

    Effects of practice of serial tests of attention in health subjects

    Journal of Clinical and Experimental Neuropsychology

    (1994)
  • M. Gillberg et al.

    Relations between performance and subjective ratings of sleepiness during a night awake

    Sleep

    (1994)
  • Y. Harrison et al.

    Sleep deprivation affects speech

    Sleep

    (1997)
  • Y. Harrison et al.

    Sleep loss impairs short and novel language tasks having a prefrontal focus

    Journal of Sleep Research

    (1998)
  • Y. Harrison et al.

    The impact of sleep deprivation on decision making: A review

    Journal of Experimental Psychology: Applied

    (2000)
  • Y. Harrison et al.

    Prefrontal neuropsychological effects of sleep deprivation in young adults—A model for healthy aging?

    Sleep

    (2000)
  • J.A. Horne

    Sleep loss and “divergent” thinking ability

    Sleep

    (1988)
  • Cited by (175)

    • The effect of 24-hour sleep deprivation on subjective time perception

      2023, International Journal of Psychophysiology
    View all citing articles on Scopus
    View full text