Effect of cognitive arousal on sleep latency, somatic and cortical arousal following partial sleep deprivation

Emerging research has shown that sleepiness, defined as the tendency to fall asleep, is not only determined by sleep pressure and time of day, but also by physiological and cognitive arousal. In this study we evaluated (i) the impact of experimentally induced cognitive arousal on electroencephalogram (EEG) defined sleep latency, and subjective, somatic and cortical arousal, and (ii) whether experimentally induced cognitive arousal enhances performance on a driving simulator test. Twelve healthy sleepers each spent three nights and the following day in the sleep laboratory: an adaptation, a cognitive arousal and a neutral testing day. In the cognitive arousal condition, a visit of a television camera crew took place and subjects were asked to be interviewed. On each testing day, a 5-min heart rate recording, subjective sleepiness and arousal scales, Multiple Sleep Latency Test and a 25-min driving simulator task were scheduled three times at 2-h intervals. Experimentally induced cognitive arousal resulted in significant increases in objective sleep latency. Significantly elevated levels of subjective and somatic arousal--as indexed by a subjective arousal scale and heart rate--were also evidenced following cognitive arousal induction. A marginally significant trend for increased cortical arousal, measured by EEG beta activity, was also found. No effects were found on driving simulator performance. These findings support the concept of cognitive arousal as a significant component in determining sleep latency. In addition, it was illustrated that cognitively induced arousal can provoke increases in somatic and possibly even cortical arousal in normal sleepers. However, this was not accompanied by an enhanced ability to perform adequately on a driving simulator test.     

The influence of pre-sleep cognitive arousal on sleep onset processes

Cognitive hyperarousal, resulting in enhanced cognitive activation, has been cited as an important contributor to the development and preservation of insomnia. To further understand this process, our study examined the effects of acutely-induced pre-sleep cognitive hyperarousal on sleep onset processes in healthy volunteers. Following an adaptation night, 15 subjects slept two nights in our sleep laboratory: one reference night and another one with cognitive arousal induction, in a counterbalanced order. In the cognitive arousal condition, subjects worked through half an hour of cognitive tasks without interference of an emotional component prior to retiring to bed. Objective sleep onset latency was significantly prolonged in the cognitive arousal condition compared to the reference condition. Significantly more high frequency activity was recorded during the first and second deep-sleep period. Moreover, differences in heart rate and proximal temperature during and after sleep onset were observed in the nights after the cognitive induction. Pre-sleep cognitive activation successfully induced a significant cognitive load and activation in our subjects to influence subsequent sleep (onset) processes.     

The effects of cognitive complexity and arousal on client perception of counselor nonverbal behavior

This analogue study examined the interaction between cognitive complexity and arousal in client discrimination of counselor positive and negative nonverbal behavior. Thirty university students, divided into low, medium, and high arousal conditions, viewed a videotaped counseling interview in which the counselor nonverbal behaviors were varied systematically and then rated counselor perceived expertness. The results showed that subjects discriminated counselor positive and negative nonverbal behaviors in the early portion of a 30-minute interview, but this tendency deteriorated quickly as the interview progressed. Also, there was a significant interaction between subject cognitive complexity and arousal level. Implications of the findings are discussed.     

Effects of unrecognized physiological residual arousal on emotional experience

This study investigated the effect of residual arousal on perceived positive and negative emotion, and the relationship between the valence of emotion and cardiovascular and cardiorespiratory reactivity. A total of 74 participants were randomly assigned to either a Residual Arousal (exercise‐induced) group or a No Residual Arousal (no exercise) group. Following the arousal manipulation, participants watched a video that elicited positive emotion and a video that elicited negative emotion. Within‐person differences revealed greater discrepancies between participants’ reports of positive and negative emotions in response to the videos, indicating that residual arousal caused stronger positive and negative emotions. With regard to physiological reactivity, participants in the No Residual Arousal group exhibited lower heart rate, respiration amplitude, and heart rate variability (LF /HF ratio) during the negative video than during the positive video, suggesting that the positive and negative videos had different influences on physiology. These results support the hypothesis that autonomic activation may be nonspecific with regard to the genesis of emotion, but once a person becomes emotional, physiological reactivity may differ between emotions.     

When sleep is perceived as wakefulness: an experimental study on state perception during physiological sleep

While electrophysiologically measured sleep and perception of sleep generally concur, various studies have shown this is not always the case. The objective of the present study was to assess the perception of actual state during sleep by the technique of planned awakenings and interviewing subjects on the preawakening state. Sixty-eight (43 females, 25 males) young (mean age: 24.1, SD 5.1 years) normal sleeping subjects were deliberately awakened out of consolidated sleep, either stage 2 (S2), or REM sleep, during the first night in a non-clinical sleep laboratory. While the preawakening state was experienced as sleep in 48 cases (70.6%), it was experienced as wakefulness in 20 cases (29.4%). The percentage of awake judgements was somewhat, but not significantly, higher for awakenings out of S2 (38.2%), to REM sleep (20.6%). The proportion of mismatches between electrophysiologically defined sleep and state judgements was time-dependent with more awake judgements for REM sleep in the second half of the sleep period (41.7%) than in the first one (17.4%). Those subjects who made an awake judgement more frequently had a feeling of being aware of the situation and their surroundings than those who made a sleep judgement (80% versus 33%). Awareness during sleep may be a cognitive style, which favours mismatches between state perception and electrophysiologically defined sleep. Sleep periods with concordant or discordant state judgements did not differ in electrophysiologically defined sleep onset latency, sleep efficiency, or sleep state distribution.     

Effects of age and sleeping position on arousal from sleep in preterm infants

STUDY OBJECTIVES: Preterm infants are at increased risk of sudden infant death syndrome (SIDS). We investigated whether the prone sleeping position impaired arousal from sleep in healthy preterm infants and whether this impairment was related to cardiorespiratory variables, temperature or postnatal age. DESIGN: Longitudinal SETTING/PARTICIPANTS: 14 healthy preterm infants (mean 32 +/- 0.4 weeks) were studied using daytime polysomnography on 4 occasions: 36-38 weeks postconception age, 2 to 3 weeks postterm, 2 to 3 months postterm, and 5 to 6 months postterm. Interventions: N/A. MEASUREMENTS: Multiple measurements of arousal threshold (cm H2O) in response to air-jet stimulation applied alternately to the nares were made in both active sleep and quiet sleep when infants slept both prone and supine. RESULTS: Arousal thresholds were significantly higher in both AS and QS when infants slept prone at 36 to 38 weeks postconception age and 2 to 3 months postterm but not at 2 to 3 weeks or 5 to 6 months postterm. These increases were independent of any sleep position-related changes in either rectal or abdominal skin temperature, respiratory rate, oxygen saturation or heart rate. CONCLUSIONS: At the age when the risk of SIDS is highest, the prone position significantly impairs arousal from both active sleep and quiet sleep in healthy infants born prematurely. This impairment in arousability occurred with no clinically significant changes in cardiorespiratory parameters or body temperature. Decreased arousability from sleep in the prone position may explain its role as a risk factor for SIDS.     

Effects of arousal level on the physiological responding on the Concealed Information Test

This study examined effects of arousal level on the physiological responses in a polygraph examination using the Concealed Information Test (CIT). Thirty-nine healthy college students were tested with or without evaluative observation. Electrodermal activity, blood pressure, heart rate, normalized pulse volume, and respiration were recorded. Observation elevated participants' arousal level, which was manifested in self-reports, high skin conductance level, and low normalized pulse volume (i.e., vasoconstriction). However, differential reactivity to critical and non-critical items on the physiological measures was less affected by observation. These results suggested that participants' arousal level has little effect on differential physiological reactivity on the CIT.     

Psychological stress is associated with heightened physiological arousal during NREM sleep in primary insomnia

The objective of this study was to evaluate cross-sectional relationships among symptoms of psychological stress, sleep, and physiological arousal during non-rapid eye movement (NREM) sleep in a sample of 30 patients with chronic, primary insomnia (mean age, 30.2 years, 60% female). Study measures included indexes of subjective stress, visually scored sleep, and physiological arousal during NREM sleep: quantitative electroencephalogram (QEEG) and quantitative electrocardiogram (QEKG) measures. Psychological stress was more strongly related to indexes of physiological arousal during NREM sleep than to visually scored measures of sleep. Higher levels of perceived stress were associated with decreased EEG delta power (rho = -0.50, p < .01) and increased EEG beta power (rho = 0.38, p < .05). Increased frequency of stress-related avoidance behaviors was associated with decreased EKG high-frequency power (rho = -0.46, p < .05). Although QEEG measures were significantly correlated with sleep maintenance (QEEG delta power rho = 0.45, p < .01; QEEG beta power rho = -0.54, p < .01) and time spent in delta sleep (QEEG delta power rho = 0.65, p < .001; QEEG beta power rho = -0.65, p < .001), QEKG measures were unrelated to visually scored measures of sleep. Perceived stress and stress-related avoidance behaviors were associated with multiple indexes of physiological arousal during NREM sleep in patients with chronic, primary insomnia.     

Effects of total sleep deprivation on the perception of action capabilities

Changes in a subject’s state have been shown to modulate the perceptual update of his or her action capabilities. In parallel, sleep deprivation impairs in cognitive functions. It involves common neural structures that support the perception of successfully achieving a motor task. Thus, the study investigated the effect of 24 h of sleep deprivation on the perception of action capabilities. Twenty-four healthy participants were randomly separated into two groups (control group vs. 24 h sleep deprivation group). Participants in the control group slept at home according to their habitual sleep–wake schedule. The 24-h sleep deprivation group stayed awake in the laboratory. Participants estimated the limit of their maximal height of stepping-over a bar before and after the sleep intervention. These estimations were compared to each participant’s actual maximal stepping-over height. Physical performance (measured by maximal voluntary quadriceps contraction and repetitive vertical jumping tests) and perceptual inhibition tests (measured by choice reaction time tasks) were also performed for three sessions at three time points t ₀, t _+12h, and t _+24h with t ₀ = 8:00 a.m. for all participants. Participants in the 24-h sleep deprivation group showed impairments in perceived over-stepping performance and impaired cognitive functioning (higher reaction time), while no changes were observed in actual performance in the over-stepping, voluntary quadriceps contraction, or jumping tasks. The cognitive processing of inputs that specify the estimated consequences of motor action is discussed as the main explanation for the inability to successfully update the perception of action capabilities after sleep deprivation.     

The nature of arousal in sleep

The role of arousals in sleep is gaining interest among both basic researchers and clinicians. In the last 20 years increasing evidence shows that arousals are deeply involved in the pathophysiology of sleep disorders. The nature of arousals in sleep is still a matter of debate. According to the conceptual framework of the American Sleep Disorders Association criteria, arousals are a marker of sleep disruption representing a detrimental and harmful feature for sleep. In contrast, our view indicates arousals as elements weaved into the texture of sleep taking part in the regulation of the sleep process. In addition, the concept of micro-arousal (MA) has been extended, incorporating, besides the classical low-voltage fast-rhythm electroencephalographic (EEG) arousals, high-amplitude EEG bursts, be they like delta-like or K-complexes, which reflects a special kind of arousal process, mobilizing parallely antiarousal swings. In physiologic conditions, the slow and fast MA are not randomly scattered but appear structurally distributed within sleep representing state-specific arousal responses. MA preceded by slow waves occurs more frequently across the descending part of sleep cycles and in the first cycles, while the traditional fast type of arousals across the ascending slope of cycles prevails during the last third of sleep. The uniform arousal characteristics of these two types of MAs is supported by the finding that different MAs are associated with an increasing magnitude of vegetative activation ranging hierarchically from the weaker slow EEG types (coupled with mild autonomic activation) to the stronger rapid EEG types (coupled with a vigorous autonomic activation). Finally, it has been ascertained that MA are not isolated events but are basically endowed with a periodic nature expressed in non-rapid eye movement (NREM) sleep by the cyclic alternating pattern (CAP). Understanding the role of arousals and CAP and the relationship between physiologic and pathologic MA can shed light on the adaptive properties of the sleeping brain and provide insight into the pathomechanisms of sleep disturbances. Functional significance of arousal in sleep, and particularly in NREM sleep, is to ensure the reversibility of sleep, without which it would be identical to coma. Arousals may connect the sleeper with the surrounding world maintaining the selection of relevant incoming information and adapting the organism to the dangers and demands of the outer world. In this dynamic perspective, ongoing phasic events carry on the one hand arousal influences and on the other elements of information processing. The other function of arousals is tailoring the more or less stereotyped endogenously determined sleep process driven by chemical influences according to internal and external demands. In this perspective, arousals shape the individual course of night sleep as a variation of the sleep program.     

Effects of sleep deprivation on cognitive ability and skills of pediatrics residents

The stress and long working hours of medical residency have become the basis for controversy over whether current training structures and processes adversely affect residents' skills and well-being and the quality of patient care. The authors measured cognitive and skills performances of 45 sleep-deprived pediatrics residents by using questions like those on the pediatrics board certification examination and using patient-care tasks that required coordination and dexterity. The residents were randomly divided into two groups--one stayed awake for 24 hours, the other for 34 hours--and were tested on cognitive and skills performances before and after sleep deprivation. Sleep deprivation did not have a significant effect on cognitive performance. Of the three skills tested, the residents overall needed more time to perform umbilical artery catheterization, but the group deprived of sleep for 34 hours performed vein cannulation more quickly than the group deprived for 24 hours. Implications for these findings are discussed in the context of the ongoing controversy over the structure and process of medical education.     

Effects of sleep deprivation and exercise on cognitive, motor performance and mood

This study examined the effect of 30 h of sleep deprivation and intermittent physical exercise, on both cognitive and psychomotor function as well subjective ratings of mood. Six subjects with the following physical characteristics participated in the study (Mean +/- S.D.): age 22 +/- 0.3 years, height 180 +/- 5 cm, body mass: 77 +/- 5 kg, VO2peak 44 +/- 5 ml kg(-1) min(-1). Three subjects engaged in normal sedentary activities while three others cycled on a cycle ergometer at 50% VO2peak for 20 min out of every 2 h during 30 h of sleep deprivation. One week later sleep deprivation was repeated with a cross over of subjects. Every 4 h, subjects completed simple and two-choice reaction time tasks at both rest and during exercise, a computerized tracking task, a number cancellation task, and an assessment of subjective mood state as measured by the POMS questionnaire. A 3 x 4 repeated measures ANOVA revealed that resting but not exercising reaction times were significantly slower with sleep deprivation. Sleep deprivation was also associated with significantly greater negative disturbances to subjective vigour, fatigue and depression assessed by the Profile of Mood States questionnaire. Compared to those who have been deprived of sleep alone, individuals that performed 5 h of intermittent moderate exercise during 30 h of sleep deprivation appeared to be more vulnerable to negative mood disturbances and impairment in reaction times. This could result in greater risk of accident due to a reduced capacity to respond quickly.     

Clonidine has a paradoxical effect on cyclic arousal and sleep bruxism during NREM sleep

Study Objective:

Clonidine disrupts the NREM/REM sleep cycle and reduces the incidence of rhythmic masticatory muscle activity (RMMA) characteristic of sleep bruxism (SB). RMMA/SB is associated with brief and transient sleep arousals. This study investigates the effect of clonidine on the cyclic alternating pattern (CAP) in order to explore the role of cyclic arousal fluctuation in RMMA/SB.

Design:

Polysomnographic recordings from a pharmacological study.

Setting:

University sleep research laboratory.

Participants and Interventions:

Sixteen SB subjects received a single dose of clonidine or placebo at bedtime in a crossover design.

Measurements and Results:

Sleep variables and RMMA/SB index were evaluated. CAP was scored to assess arousal instability between sleep-maintaining processes (phase A1) and stronger arousal processes (phases A2 and A3). Paired t-tests, ANOVAs, and cross-correlations were performed. Under clonidine, CAP time, and particularly the number of A3 phases, increased (P ≤ 0.01). RMMA/SB onset was time correlated with phases A2 and A3 for both placebo and clonidine nights (P ≤ 0.004). However, under clonidine, this positive correlation began up to 40 min before the RMMA/SB episode.

Conclusions:

CAP phase A3 frequency increased under clonidine, but paradoxically, RMMA/SB decreased. RMMA/SB was associated with and facilitated in CAP phase A2 and A3 rhythms. However, SB generation could be influenced by other factors besides sleep arousal pressure. NREM/REM ultradian cyclic arousal fluctuations may be required for RMMA/SB onset.

Citation:

Carra MC; Macaluso GM; Rompré PH; Huynh N; Parrino L; Terzano MG; Lavigne GJ. Clonidine has a paradoxical effect on cyclic arousal and sleep bruxism during NREM sleep. SLEEP 2010;33(12):1711-1716.     

The effects of self-induced mood states on behavior and physiological arousal

The effects of reading emiotionally loaded statements on behavioral tasks and physiological measures were investigated. Statements were constructed to arouse elation depression, or neutrality. Ss were both pre- and posttested on Writing Speed, Reaction Time, Decision Time, and Spontaneous Verbaliza-tions. Base rates were obtained for heart rate and galvanic skin response. Elation Ss significantly outperformed both Neutral and Depression Ss on the Reaction Time task. Scores for Neutral Ss fell between those of Elation and Depression Ss on three of the four behavioral measures. No significant differences were found on the physiological measures.     

Effects of a structured problem-solving procedure on pre-sleep cognitive arousal in college students with insomnia

Pre-sleep cognitive arousal, more specifically worry, is often reported as a distressing symptom that interferes with sleep. Using a controlled group design, a “constructive worry” intervention, similar to Espie and Lindsay's (1987) “worry control” procedure, was tested for its effects on pre-sleep cognitive arousal in an undergraduate population reporting insomnia. After 2 baseline nights, participants (N = 33) either recorded possible solutions to worries (constructive worry group) or recorded worries and completed worry questionnaires (worry group) for 5 nights. As hypothesized, the constructive worry group had decreased pre-sleep cognitive arousal relative to the worry group and relative to baseline scores. This study provides further support for augmenting existing insomnia treatments with cognitive interventions to successfully treat the complaint of pre-sleep cognitive arousal.     

Cluster arousal analysis in chronic pain-disturbed sleep

A new cluster arousal analysis system was developed to quantify microdisturbances in the sleep architecture. The system was evaluated in 10 healthy volunteers and the sleep of 23 outpatients with chronic low back pain was investigated before and after a special rehabilitative training. The comparison of sleep parameters before and after the treatment showed a significant reduction of the cluster disturbed sleep (CDS), whereas sleep efficiency and the number of stage shifts remained unchanged. The reduction of the CDS correlated with a reduction of depression scale. This cluster arousal analysis appears to be a sensitive tool for evaluating alterations in the sleep microstructure.     

On arousal from sleep: time-frequency analysis

Time-frequency analysis of the heart rate variability during arousal from sleep, with and without EMG activation, coming from five obese healthy subjects was performed. Additionally, a comparative analysis of three time-frequency distributions, smooth pseudo Wigner–Ville (SPWVD), Choi–Williams (CWD) and Born–Jordan distribution (BJD) is presented in this study. SPWVD showed higher capacity for eliminating the cross terms independently of the signal. After applying Hilbert transformation to real signals BJD and CWD lost some important mathematic properties as marginals, on the contrary PSWVD remains unchanged. BJD showed results comparable with CWD. During arousal episodes, analogous energy distribution and spectral indexes were obtained by the three time-frequency representations. Arousals with chin activity presented stronger changes in RR intervals and LF (related to sympathetic activity) component, being statistically different with respect to arousal without chin activity, only around the period of maximum change in β activity on the EEG. These results suggest a more evident stress for the heart when an arousal is related to external muscular activity.     

The relationship between women's subjective and physiological sexual arousal

Previous literature presents discordant results on the relationship between physiological and subjective sexual arousal in women. In this study, the use of hierarchical linear modeling (HLM) revealed a significant concordance between continuous measures of physiological and subjective sexual arousal as assessed during exposure to erotic stimuli in a laboratory setting. We propose that past studies that have found little or no association between the two measures may have been in part limited by the methodology and statistical analyses employed.