Overnight Delta Dynamics Associated with Daytime Psychomotor Performance in Adults with Insomnia and Healthy Controls

Sleep Physiology and Neurocognition Among Adolescents With Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Few studies have characterized the nature of sleep problems among adolescents with attention-deficit/hyperactivity disorder (ADHD) using polysomnography (PSG). Additionally, although adolescents with ADHD and adolescents with sleep disturbances display similar neurocognitive deficits, the role of sleep in contributing to neurocognitive impairment in adolescent ADHD is unknown. This study investigated differences in PSG-measured sleep among adolescents with ADHD compared with non-psychiatric controls and associations with neurocognition.

METHOD

Medication-free adolescents aged 13 to 17 (N = 62, n = 31 with ADHD; mean age = 15.3 years; 50% female) completed a diagnostic evaluation, 3 nights of ambulatory PSG, the Cambridge Neuropsychological Test Automated Battery, and subjective reports of sleep and executive functioning. Linear regressions covarying for age, sex, and pubertal status examined group differences in sleep indices, and partial Pearson correlations assessed relations between sleep and neurocognition.

RESULTS

Although adolescents with ADHD did not exhibit differences in PSG-measured sleep duration, awakenings, or latency (ps > .05) compared with non-psychiatric controls, they displayed lower slow wave sleep percentage (β = -.40) and non-rapid eye movement (NREM) electroencephalogram (EEG) delta power (β = -.29). They also exhibited greater stage 2 percentage (β = .41), NREM EEG sigma power (β = .41), and elevated self-reported sleep disturbances (ps < .05). Lower NREM EEG delta power, increased high-frequency power, and slower decline in NREM EEG delta power overnight were associated with poorer neurocognition among adolescents with ADHD.

CONCLUSION

Adolescents with ADHD reported more sleep disturbances than non-psychiatric controls and exhibited differences in sleep stage distribution and NREM sleep EEG frequency. Sleep-EEG spectral indices were associated with impaired neurocognition, suggesting that physiological sleep processes may underlie neurocognitive deficits in ADHD. Future studies may clarify whether sleep plays a causal role in neurocognitive impairments in adolescent ADHD and whether interventions normalizing sleep improve neurocognition.

PLAIN LANGUAGE SUMMARY

This study investigated the sleep physiology in a sample of 62 adolescents, 31 with attention-deficit/hyperactivity disorder (ADHD) and 31 with no psychiatric diagnoses, aged 13 to 17. The authors found that medication-free adolescents with ADHD displayed reduced time in deep slow wave sleep, and increased time in lighter stage 2 sleep, than adolescents without a psychiatric diagnosis. Results indicate that disruptions in the amount and pattern of slow wave electroencephalogram (EEG) activity, as well as increased high frequency EEG power during sleep, were associated with lower cognitive performance among adolescents with ADHD. The study findings suggest that sleep physiology may contribute to cognitive deficits in ADHD and future research should assess whether interventions normalizing sleep improve cognitive performance in adolescents with ADHD.

CLINICAL TRIAL REGISTRATION INFORMATION

Sleep Dysfunction and Neurocognitive Outcomes in Adolescent ADHD; https://clinicaltrials.gov/; NCT02897362.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. We actively worked to promote sex and gender balance in our author group. While citing references scientifically relevant for this work, we also actively worked to promote sex and gender balance in our reference list.

Sleep electroencephalography biomarkers of cognition in obstructive sleep apnea

Obstructive sleep apnea has been associated with cognitive impairment and may be linked to disorders of cognitive function. These associations may be a result of intermittent hypoxaemia, sleep fragmentation and changes in sleep microstructure in obstructive sleep apnea. Current clinical metrics of obstructive sleep apnea, such as the apnea-hypopnea index, are poor predictors of cognitive outcomes in obstructive sleep apnea. Sleep microstructure features, which can be identified on sleep electroencephalography of traditional overnight polysomnography, are increasingly being characterized in obstructive sleep apnea and may better predict cognitive outcomes. Here, we summarize the literature on several major sleep electroencephalography features (slow-wave activity, sleep spindles, K-complexes, cyclic alternating patterns, rapid eye movement sleep quantitative electroencephalography, odds ratio product) identified in obstructive sleep apnea. We will review the associations between these sleep electroencephalography features and cognition in obstructive sleep apnea, and examine how treatment of obstructive sleep apnea affects these associations. Lastly, evolving technologies in sleep electroencephalography analyses will also be discussed (e.g. high-density electroencephalography, machine learning) as potential predictors of cognitive function in obstructive sleep apnea.

Dual orexin antagonist normalized sleep homeostatic drive, enhanced GABAergic inhibition, and suppressed seizures after traumatic brain injury

STUDY OBJECTIVES

Traumatic brain injury (TBI) can result in posttraumatic epilepsy (PTE) and sleep disturbances. We hypothesized that treatment with sleep aids after TBI can ameliorate PTE.

METHODS

CD-1 mice underwent controlled cortical impact (CCI), sham injury, or no craniotomy. Sham and CCI groups underwent a monthlong daily treatment with sleep aids including a dual orexin antagonist (DORA-22) or THIP (gaboxadol) or a respective vehicle starting on the day of CCI. We performed continuous EEG (electroencephalography) recordings at week 1 and months 1, 2, and 3 for ~1 week each time. Seizure analysis occurred at all-time points and sleep analysis occurred in week 1 and month-1/2 in all groups. Subsets of CCI and sham groups were subjected to voltageclamp experiments in hippocampal slices to evaluate GABAergic synaptic inhibition.

RESULTS

DORA-22 treatment suppressed seizures in month 1-3 recordings. TBI reduced the amplitude and frequency of miniature inhibitory synaptic currents (mIPSCs) in dentate granule cells and these changes were rescued by DORA-22 treatment. Sleep analysis showed that DORA-22 increased nonrapid eye movement (NREM) sleep during lights-off whereas THIP increased REM sleep during lights-on in week 1. Both treatments displayed subtle changes in time spent in NREM or REM at month-1/2 as well. TBI not only increased normalized EEG delta power (NΔ) at week-1 and month-1 but also resulted in the loss of the homeostatic diurnal oscillation of NΔ, which was restored by DORA-22 but not THIP treatment.

CONCLUSIONS

Dual orexin antagonists may have a therapeutic potential in suppressing PTE potentially by enhancing GABAergic inhibition and impacting sleep homeostatic drive.