Louise Beattie

Social interactions, emotion and sleep: A systematic review and research agenda

Sleep and emotion are closely linked, however the effects of sleep on socio-emotional task performance have only recently been investigated. Sleep loss and insomnia have been found to affect emotional reactivity and social functioning, although results, taken together, are somewhat contradictory. Here we review this advancing literature, aiming to 1) systematically review the relevant literature on sleep and socio-emotional functioning, with reference to the extant literature on emotion and social interactions, 2) summarize results and outline ways in which emotion, social interactions, and sleep may interact, and 3) suggest key limitations and future directions for this field. From the reviewed literature, sleep deprivation is associated with diminished emotional expressivity and impaired emotion recognition, and this has particular relevance for social interactions. Sleep deprivation also increases emotional reactivity; results which are most apparent with neuro-imaging studies investigating amygdala activity and its prefrontal regulation. Evidence of emotional dysregulation in insomnia and poor sleep has also been reported. In general, limitations of this literature include how performance measures are linked to self-reports, and how results are linked to socio-emotional functioning. We conclude by suggesting some possible future directions for this field.

Altered emotion perception in insomnia disorder.

STUDY OBJECTIVES Chronic insomnia is a prevalent sleep disorder that negatively affects daytime functioning and confers risk for the future development of psychiatric disorder. Patients with insomnia often report problems with emotion regulation and impaired social interactions. Moreover, experimental sleep loss in healthy adults is associated with altered reactivity to and interpretation of emotional information. In the current study, we investigated socioemotional processing in patients with chronic insomnia disorder relative to healthy good sleepers. DESIGN Between-groups comparison. SETTING Sleep Research Laboratory. PARTICIPANTS Patients with well-defined psychophysiological insomnia (PI; n = 16), free from psychiatric disorder, and an age- and sex-matched control group of good sleepers (GS; n = 15). INTERVENTIONS N/A. MEASUREMENT AND RESULTS All participants completed a facial expression recognition task, between 18:00 and 19:00, requiring participants to categorize and rate the intensity of four emotional expression categories: anger, fear, happiness, and sadness. People with PI did not differ from GS with respect to categorization of facial expressions. However, in terms of intensity judgements, across all emotion categories, patients tended to rate faces as less emotionally intense (Cohens d = 0.70). Specifically, they rated expressions displaying sadness and fear as significantly less emotionally intense than healthy GS (both P < 0.05; Cohens d = 0.77 and 0.89, respectively). Measures of sleepiness (Psychomotor Vigilance Test, Karolinska Sleepiness Scale) or self-reported sleep were not reliably associated with emotional intensity ratings. However, anxiety and depression were negatively related to intensity ratings. CONCLUSION For the first time we show that chronic insomnia is associated with reduced ratings of emotion intensity for face expressions displaying sadness and fear. Further work is required to elucidate possible mechanisms and pathways underlying insomnia-related emotional impairment.

How are normal sleeping controls selected? A systematic review of cross-sectional insomnia studies and a standardized method to select healthy controls for sleep research

There appears to be some inconsistency in how normal sleepers (controls) are selected and screened for participation in research studies for comparison with insomnia patients. The purpose of the current study is to assess and compare methods of identifying normal sleepers in insomnia studies, with reference to published standards. We systematically reviewed the literature on insomnia patients, which included control subjects. The resulting 37 articles were systematically reviewed with reference to the five criteria for normal sleep specified by Edinger et al. In summary, these criteria are as follows: evidence of sleep disruption, sleep scheduling, general health, substance/medication use, and other sleep disorders. We found sleep diaries, polysomnography (PSG), and clinical screening examinations to be widely used with both control subjects and insomnia participants. However, there are differences between research groups in the precise definitions applied to the components of normal sleep. We found that none of the reviewed studies applied all of the Edinger et al. criteria, and 16% met four criteria. In general, screening is applied most rigorously at the level of a clinical disorder, whether physical, psychiatric, or sleep. While the Edinger et al. criteria seem to be applied in some form by most researchers, there is scope to improve standards and definitions in this area. Ideally, different methods such as sleep diaries and questionnaires would be used concurrently with objective measures to ensure normal sleepers are identified, and descriptive information for control subjects would be reported. Here, we have devised working criteria and methods to be used for the assessment of normal sleepers. This would help clarify the nature of the control group, in contrast to insomnia subjects and other patient groups.

Attention to beds in natural scenes by observers with insomnia symptoms

Attention biases to sleep-related stimuli are held to play a key role in the development and maintenance of insomnia, but such biases have only been shown with controlled visual displays. This study investigated whether observers with insomnia symptoms allocate attention to sleep-related items in natural scenes, by recording eye movements during free-viewing of bedrooms. Participants with insomnia symptoms and normal sleepers were matched in their visual exploration of these scenes, and there was no evidence that the attention of those with insomnia symptoms was captured more quickly by sleep-related stimuli than that of normal sleepers. However, the insomnia group fixated bed regions on more trials and, once fixated on a bed, also remained there for longer. These findings indicate that sleep stimuli are particularly effective in retaining visual attention in complex natural scenes.

Perceptual impairment in face identification with poor sleep

Previous studies have shown impaired memory for faces following restricted sleep. However, it is not known whether lack of sleep impairs performance on face identification tasks that do not rely on recognition memory, despite these tasks being more prevalent in security and forensic professions—for example, in photo-ID checks at national borders. Here we tested whether poor sleep affects accuracy on a standard test of face-matching ability that does not place demands on memory: the Glasgow Face-Matching Task (GFMT). In Experiment 1, participants who reported sleep disturbance consistent with insomnia disorder show impaired accuracy on the GFMT when compared with participants reporting normal sleep behaviour. In Experiment 2, we then used a sleep diary method to compare GFMT accuracy in a control group to participants reporting poor sleep on three consecutive nights—and again found lower accuracy scores in the short sleep group. In both experiments, reduced face-matching accuracy in those with poorer sleep was not associated with lower confidence in their decisions, carrying implications for occupational settings where identification errors made with high confidence can have serious outcomes. These results suggest that sleep-related impairments in face memory reflect difficulties in perceptual encoding of identity, and point towards metacognitive impairment in face matching following poor sleep.

Sleep-related attentional bias for tired faces in insomnia: evidence from a dot-probe paradigm

People with insomnia often display an attentional bias for sleep-specific stimuli. However, prior studies have mostly utilized sleep-related words and images, and research is yet to examine whether people with insomnia display an attentional bias for sleep-specific (i.e. tired appearing) facial stimuli. This study aimed to examine whether individuals with insomnia present an attentional bias for sleep-specific faces depicting tiredness compared to normal-sleepers. Additionally, we aimed to determine whether the presence of an attentional bias was characterized by vigilance or disengagement. Forty-one individuals who meet the DSM-5 criteria for Insomnia Disorder and 41 normal-sleepers completed a dot-probe task comprising of neutral and sleep-specific tired faces. The results demonstrated that vigilance and disengagement scores differed significantly between the insomnia and normal-sleeper groups. Specifically, individuals with insomnia displayed difficulty in both orienting to and disengaging attention from tired faces compared to normal-sleepers. Using tired facial stimuli, the current study provides novel evidence that insomnia is characterized by a sleep-related attentional bias. These outcomes support cognitive models of insomnia by suggesting that individuals with insomnia monitor tiredness in their social environment.

How does sleep affect the perception of facial emotion

In the past 10 years, there has been increasing interest in the role of sleep in socioemotional performance, and this has been reflected in experimental tasks using facial emotion perception paradigms [1]. However, a diversity of tasks have been employed, and these would seem to be linked to apparent discrepant results as to whether and how sleep affects the perception of facial emotion. I will discuss in turn differences in samples, experimental stimuli and tasks, and dependent variables, with regard to these tasks. Firstly, there are clear differences in the samples used. These include healthy participants subject to sleep deprivation (e.g. Refs. 2–5) and sleep restriction (e.g. Refs. 6–8) paradigms, as well as medication which affects sleep (e.g. Refs. 9 and 10]), sleep parameters, and insomnia symptoms [11, 12], and the clinical sleep conditions of insomnia disorder [13, 14], sleep apnea [14], and narcolepsy with cataplexy [15]. Gender-specific effects have been investigated (e.g. Refs. 2, 5–8, and 16). Samples also differ with regard to size and age, which included adolescents (e.g. Ref. 17), young adults (e.g. Refs. 2 and 11), and middle-aged adults (e.g. Ref. 13). However, adolescence is considered to be the period at which mental health conditions first emerge [18, 19] and sleep disruption is common in college students [20]. Future studies should consider the interactions of vulnerability/resilience in regard to tasks (e.g. Refs. 21 and 22). Furthermore, the absence of a clinical sleep disorder does not necessarily mean that participants are “good” sleepers (cf. the work of Beattie et al. [23]). Secondly, there are differences in the experimental stimuli and tasks. Specifically, the numbers of emotions considered varied, as did their intensity levels and presentation duration, and order of presentation. Although a smaller number of emotion categories may make it harder to detect effects, emotion faces have been found to correspond to both basic emotion and dimensional perspectives [24], see also Ref. 25, and additional emotions would be likely to be associated with these general categories. Importantly, it is well known that there can be emotion-specific effects on recognition [26]. Full intensity levels may also make it harder to detect effects; however, precise ways in which the muscle units (action units) of the human face combine to form subtle expressions may not be the mid-point of the “full” expression (cf. Refs. 27–29). Furthermore, the procedure to “morph” faces affects spatial frequency information, and it may therefore be important to consider the effects of sleep on visual perception in general. A longer presentation duration may make it easier for a facial emotion to be recognized [30], although it should be noted that extended presentation durations risk ecological validity (cf. Ref. 31). Similarly, presenting emotion faces in a blocked design also affects ecological validity, and means that categorization is harder to assess. However, such a task would be required in order to assess recognition sensitivity and bias in accordance with signal detection theory. The number of identities on which emotions were depicted also varied, alongside the number of repetitions. It should also be noted that there is recent evidence of effects of sleep on unfamiliar face matching [32], and unfamiliar faces are typically employed. A majority of studies have used static faces (but see the work of Holding et al. [11]). Thirdly, various dependent variables have been used. Behavioral responses include categorization judgements, alongside reaction times and intensity judgements, although emotion matching has also been used [6], as has the identification of specific emotions [17], and rated intensity of specific emotions [2]. The precise combination of stimuli with task demands and response variables also seem likely to matter. Reaction times have been reported less frequently, as have error patterns (but see Refs. 4 SLEEPJ, 2018, 1–3

M-B-027 DOES TIME OF TESTING AFFECT EMOTION PERCEPTION?

Introduction and Objectives: Vigilance and mood are known to be affected by sleep, with circadian phase modulating performance and affective experience. These are also affected by sleep loss, with increased lability to emotional images. Time of testing could therefore affect emotion task performance. The perception of emotion from faces has special significance, as faces can be used to communicate information like threat and danger. Materials and Methods: In a first study, participants (n=55, mean age 25, 43 females) completed an emotion recognition task. Normal sleepers and poor sleepers were identified, and two time of day groups were created. In a follow-up study designed to control for time since awakening, good sleepers (n=36, mean age = 22, 25 females) were asked to categorize emotional faces and images as angry, fearful, happy or sad. Performance was assessed at 3, 6, 9, or 12 hours since waking, based on sleep diary responses. Results: Pilot data indicated a significant interaction of emotion, time of day and sleep group (P<0.05). Follow up tests showed normal sleepers were less sensitive to angry and fearful faces after 3pm (for both, P<0.05). Results from the current study indicate that participants tested at 12 hours are more sensitive towards happy facial expressions than those tested at 3 hours (P<0.05). Participants tested at 9 and 12 hours could also be more sensitive towards angry facial expressions than those tested at 6 hours (for both, P<0.1). Ongoing work aims to clarify these effects. Conclusion: These results indicate that time of day could affect sensitivity towards angry faces in particular, suggesting that sensitivity towards different emotions varies over the course of the day. This finding adds to the literature linking sleep and emotion, and learning how sleep and emotion perception are linked may help inform models of insomnia development. Acknowledgements: This research was supported by an ESRC studentship to L. Beattie, an EPS research bursary to M. Bindemann and N. Forsberg, and a Carnegie Trust vacation scholarship to M. Holm.