Sleep spindle density is associated with worry in children with generalized anxiety disorder and healthy controls

Sleep spindle activity is associated with state- and trait-based emotion in healthy school-aged children

BACKGROUND

While connections between children's sleep and their daytime functioning are well established, less is known about the microstructural features of sleep that support emotional wellbeing. Investigating these relationships in healthy children may provide insight into adaptive emotional development. We therefore examined associations between non-rapid eye movement (N2) sleep spindles and both state- and trait-based measures of emotion.

METHODS

A sample of 30 children (7-11 years) without psychiatric disorders completed a baseline assessment, one night of at-home polysomnography (PSG), and an in-lab emotional state assessment the next day including self-reported arousal in response to affective images. Trait-based measures of anxiety and depression as well as savoring, a positive emotion regulatory strategy, were also completed. N2 sleep spindle parameters, including spindle density (number/min) and peak frequency in central regions, were detected using an automated algorithm.

RESULTS

Greater spindle density was significantly associated with decreased state-based emotional arousal towards negative affective images, and greater spindle peak frequency was associated with greater trait-based use of savoring. However, neither spindle parameter was associated with child anxiety or depressive symptoms.

CONCLUSIONS

Findings align with and expand on prior research to suggest that N2 sleep spindles support adaptive emotional functioning in school-aged children.

Attentional Control Accounts for the Association Between Anxiety Sensitivity and Sleep Efficiency in Clinic-Referred Youth

Youth with anxiety disorders report difficulty falling asleep and returning to sleep after sleep onset (i.e., poor sleep efficiency). Anxiety sensitivity, the excessive attention to physical symptoms of anxiety and their threatening interpretations, has been linked to poor sleep efficiency. We tested a conceptual model wherein attentional control, attentional focusing and attentional shifting would account for the relationship between anxiety sensitivity and poor sleep efficiency. 255 youths (6-17 years old, 78% Hispanic/Latino) who presented to a university-based research clinic completed measures on anxiety sensitivity, sleep, and attentional control. Poorer sleep efficiency was significantly correlated with higher anxiety sensitivity and lower attentional control, attentional focusing, and attentional shifting. Higher anxiety sensitivity was significantly correlated with lower attentional control and attentional focusing. Attentional control and attentional focusing, not attentional shifting, accounted for the relationship between anxiety sensitivity and poor sleep efficiency. These findings identify attentional control and attentional focusing as variables that may explain the association between anxiety sensitivity and sleep efficiency in youth.

Sleep to Internalizing Pathway in Young Adolescents (SIPYA): A proposed neurodevelopmental model

The prevalence of internalizing disorders, i.e., anxiety and depressive disorders, spikes in adolescence and has been increasing amongst adolescents despite the existence of evidence-based treatments, highlighting the need for advancing theories on how internalizing disorders emerge. The current review presents a theoretical model, called the Sleep to Internalizing Pathway in Young Adolescents (SIPYA) Model, to explain how risk factors, namely sleep-related problems (SRPs), are prospectively associated with internalizing disorders in adolescence. Specifically, SRPs during late childhood and early adolescence, around the initiation of pubertal development, contribute to the interruption of intrinsic brain networks dynamics, both within the default mode network and between the default mode network and other networks in the brain. This interruption leaves adolescents vulnerable to repetitive negative thought, such as worry or rumination, which then increases vulnerability to internalizing symptoms and disorders later in adolescence. Sleep-related behaviors are observable, modifiable, low-stigma, and beneficial beyond treating internalizing psychopathology, highlighting the intervention potential associated with understanding the neurodevelopmental impact of SRPs around the transition to adolescence. This review details support for the SIPYA Model, as well as gaps in the literature and future directions.

Spindle-related brain activation in patients with insomnia disorder: An EEG-fMRI study

Sleep spindles have been implicated in sleep protection, depression and anxiety. However, spindle-related brain imaging mechanism underpinning the deficient sleep protection and emotional regulation in insomnia disorder (ID) remains elusive. The aim of the current study is to investigate the relationship between spindle-related brain activations and sleep quality, symptoms of depression and anxiety in patients with ID. Participants (n = 46, 28 females, 18-60 years) were recruited through advertisements including 16 with ID, according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, and 30 matched controls. Group differences in spindle-related brain activations were analyzed using multimodality data acquired with simultaneous electroencephalography and functional magnetic resonance imaging during sleep. Compared with controls, patients with ID showed significantly decreased bilateral spindle-related brain activations in the cingulate gyrus (familywise error corrected p ˂ 0.05, cluster size 4401 mm³). Activations in the cingulate gyrus were negatively correlated with Pittsburgh Sleep Quality Index scores (r = -0.404, p = 0.005) and Self-Rating Anxiety Scale scores (r = -0.364, p = 0.013), in the pooled sample. These findings underscore the key role of spindle-related brain activations in the cingulate gyrus in subjective sleep quality and emotional regulation in ID.

Changes in sleep structure and sleep spindles are associated with the neuropsychiatric profile in paradoxical insomnia

AIM

Sleep spindles have an important role in the pathophysiology and perception of sleep. We aimed to investigate the link between sleep spindles and microstructural architecture of sleep in regard to psychiatric characteristics in paradoxical insomnia.

METHOD

A total of 40 participants (20 with paradoxical insomnia, 20 healthy controls) were included in the study. All participants were evaluated by somnologists and undergone a full-night polysomnography at sleep laboratory. In addition, psychiatric interview was made by the same psychiatrist, and questionnaires were performed to assess the dimensions of the personality such as the neuroticism or extroversion (Eysenck Personality Questionnaire, EPQR-A); to evaluate the tendency to exaggerate somatic perceptions (Somatosensory Amplification Scale, SSAS), somatic parts of dissociation (Somatoform Dissociation Questionnaire, SDQ-20), and somatization (Somatization Scale, SS); to measure participants' feelings about their health and disease anxiety (Health Anxiety Inventory, HAI-18), and the level of uncontrollable and persistent anxiety (Penn State Worry Questionnaire, PSWQ); to investigate the tendency to ruminative thinking (Ruminative Thought Style Questionnaire, RTSQ), alexithymia (Toronto Alexithymia Scale, TAS-20); and to define the presence and the severity of depressive symptoms (Beck Depression Inventory, BDI).

RESULTS

The duration and frequency of the sleep spindles were similar between two groups, while the density was significantly decreased in paradoxical insomnia. The duration of sleep spindles, on the other hand, showed positive correlations with the extroversion dimension scores of EPQR-A and PSWQ scores.

DISCUSSION

Sleep protective mechanisms are disturbed in paradoxical insomnia as shown by the lower density of sleep spindles. In addition, fast spindle activity is associated with the personality traits, characterized by an increase in the expression of feelings and the level of anxiety.

A meta-analysis of accelerometer sleep outcomes in healthy children based on the Sadeh algorithm: the influence of child and device characteristics

STUDY OBJECTIVES

Children often experience sleep problems, with a negative impact on mood, behavior, cognitive function, and other aspects of mental and physical health. Accelerometers are widely used to assess sleep, but general reference values for healthy children do not yet exist. The aim of this meta-analysis was to determine mean values for wake after sleep onset (WASO), sleep efficiency (SE), total sleep time (TST) and sleep onset latency (SOL), and to determine the effect of child and accelerometer-characteristics.

METHODS

A search included studies with healthy children, 0-18 years, reporting WASO, SE, TST, and/or SOL, calculated with the Sadeh algorithm. Meta-analyses with random effects produced pooled estimate means per outcome. Meta-regression analyses determined the effect of age, sex, placement site and accelerometer type.

RESULTS

Eighty-three studies (9,068 participants) were included. Pooled means were 63 min (95% CI 57 to 69) for WASO, 88% (95% CI 87 to 89) for SE, 477 min (95% CI 464 to 491) for TST and 19 min (95% CI 17 to 22) for SOL. Heterogeneity was high (95%-99%). TST decreased with age and there was an age-effect on SOL. SE differed between wrist and ankle (used in age 0-24 months) placement, and between piezoelectric and MEMS-type accelerometers. No differences were found between boys and girls, although this number of studies was small.

CONCLUSIONS

We found differences in almost all investigated outcomes and heterogeneity was high. Therefore, we advise to use a study-specific control sample until more robust reference values are available. Future research should narrow the methodological heterogeneity and produce larger datasets, needed to establish these reference values.

Sleep spindles in children with restless sleep disorder, restless legs syndrome and normal controls

OBJECTIVE

To analyze and identify differences in sleep spindles in children with restless sleep disorder (RSD), restless legs syndrome (RLS) and normal controls.

METHODS

PSG (polysomnography) from children with RSD, RLS and normal controls were analyzed. Sleep spindle activity was detected on one frontal and one central electrode, for each epoch of N2 and N3 sleep. Sleep spindle density, duration and intensity (density × duration) were then obtained and used for analysis.

RESULTS

Thirty-eight children with RSD, twenty-three children with RLS and twenty-nine controls were included. The duration of frontal spindles in sleep stage N2 was longer in children with RSD than in controls. Frontal spindle density and intensity tended to be increased in RSD children. No significant differences were found for central spindles.

CONCLUSION

Children with RSD had longer frontal spindles. This finding may contribute to explain the occurrence of excessive movement activity during sleep and the presence of daytime symptoms.

SIGNIFICANCE

Recent research has demonstrated that children with RSD have increased NREM instability and sympathetic activation during sleep. Analyzing sleep spindles in children with RSD in comparison with children with RLS and controls adds to our understanding of the pathophysiology or RSD and its effects on daytime impairment.

Association of sleep spindle activity and sleepiness in children with sleep-disordered breathing

STUDY OBJECTIVES

The association of snoring and sleep-disordered breathing (SDB) with daytime sleepiness is well documented; however, the exact mechanisms, and especially the role of sleep microstructure that may account for this association remain incompletely understood. In a cohort of children with SDB, we aimed to compare sleep spindle activity between children with daytime sleepiness versus those without daytime sleepiness.

METHODS

Children with SDB who reported daytime sleepiness were recruited and compared with age- and sex-matched SDB controls. Polysomnographic recordings were analyzed evaluating sleep spindle activity. A statistical comparison was carried out in both groups to assess the association between sleepiness and sleep spindle activity.

RESULTS

Thirty-three children with SDB (mean age: 7.5 ± 1.7 years) were included, 10 with and 23 without daytime sleepiness. Spindle activity was lower in children with daytime sleepiness compared with those without; in stage N2, median (interquartile range) sleep spindle indexes were 77.5 (37.3) and 116.9 (71.2) (P = .015), respectively.

CONCLUSIONS

Spindles were significantly reduced in children with SDB and daytime sleepiness. The exact mechanisms of this association remain unknown and future research is needed in order to establish the exact role of sleep spindle activity on daytime symptoms in children with SDB.