Disorders of Arousal: A Chronobiological Perspective

Parasomnias During the COVID-19 Pandemic

COVID-19 had a massive impact on sleep, resulting in overall increase of sleep disturbances. During lockdown many factors contributed to sleep disturbances, in particular changes in sleep-wake habits and stress. This article will describe the frequency and features of the principal parasomnias and the impact of the pandemic and the government restriction measures on sleep. Among different pathophysiological hypotheses, we will discuss the role of stress, considered as an expression of the allostatic load. Finally, during the pandemic, parasomnias were mainly investigated by questionnaires, with controversial results; video-polysomnographic studies are crucial to obtain a definitive diagnosis, even in critical conditions.

Diagnosis and Management of NREM Sleep Parasomnias in Children and Adults

Non-rapid eye movement (NREM) sleep parasomnias are recurrent abnormal behaviors emerging as incomplete arousals out of NREM sleep. Mounting evidence on NREM sleep parasomnias calls for an update of clinical and therapeutical strategies. In the current review, we summarize the state of the art and provide the necessary background to stimulate a critical revision of diagnostic criteria of disorders of arousal (DoA), the most common NREM sleep parasomnia. In particular, we highlight the poor sensitivity of the diagnostic items related to amnesia and absence of conscious experiences during DoA episodes, encourage the role of video-polysomnography and home-video recordings in the diagnostic and treatment work-up, and suggest three levels of diagnostic certainty based on clinical and objective findings. Furthermore, we highlight current gaps of knowledge that prevent the definition of standard guidelines and future research avenues.

Violent and Complex Behaviors and Non-Restorative Sleep Are the Main Features of Disorders of Arousal in Adulthood: Real Picture or a More Severe Phenotype?

Disorders of arousal (DoA) are NREM parasomnias characterized by motor and emotional behaviors emerging from incomplete arousals from deep sleep. DoA are largely present in pediatric populations, a period during which they are labeled as self-limited manifestations. However, an extensive literature has shown that DoA can persist in adulthood, with different characteristics from childhood DoA. Adult DoA patients usually report excessive daily sleepiness, sleep-related violence during DoA episodes or potentially harmful behaviors, which are rare in childhood. The semeiological features of DoA episodes in adulthood may complicate differential diagnoses with other motor manifestations during sleep, in particular sleep-related hypermotor epilepsy. However, it cannot be excluded that adults with DoA attending sleep centers constitute a more severe phenotype, thus not being representative of adult DoA in the general population. Video-polysomnographic studies of DoA document a spectrum of motor patterns of different complexities, the simplest of which may often go unnoticed. Despite the different complexities of the episodes, neurophysiologic studies showed the co-existence of deep sleep and wakefulness during DoA episodes or even before their onset. These aspects make DoA an ideal model to investigate the mechanisms regulating local sleep, sleep arousal and cognitive functions including spatial and temporal orientation, attention or memory.

Parasomnias related to shift work disorder among medical residents during the first year of training in Mexico

Shift work disorder (SWD) may affect medical residents because their workload, academic demands and extended work hours. This condition set residents at risk of more sleep disorders. The study compared parasomnias among residents with and without shift work disorder (SWD) and weighed their relative risk (RR) for each parasomnia. One hundred twenty-six residents participated in the study. The Munich Parasomnia Screening questionnaire and the Barger Questionnaire for SWD were used for the screening of parasomnias and SWD, respectively. Means and percentages of studied variables were compared between groups. Relative risk (RR) was calculated for each type of parasomnia. The more frequent parasomnias in residents with SWD the RR (and 95% confidence intervals) were: sleep terrors, 5.60 (1.84-17.01); confusional arousals, 3.73 (1.84-7.56); sleep paralysis, 3.27 (1.53-6.93); hypnagogic/hypnopompic hallucinations, 2.55 (1.03-6.28); somniloquies, 2.45 (1.21-4.92); and nightmares, 2.01 (1.54-2.62). Our data suggest that residents who experience SWD may be at risk of having lower threshold for the occurrence of rapid eye movement (REM) and non-REM (NREM) sleep parasomnias. Additional research is needed to confirm these results, and to further identify the contribution to this association.

EEG Activation Does Not Differ in Simple and Complex Episodes of Disorders of Arousal: A Spectral Analysis Study

PURPOSE

Disorders of arousal (DoA) are characterized by incomplete awakening from NREM sleep, with the admixture of both deep sleep and wake EEG activity. Previous observations suggested that changes in EEG activity could be detected in the seconds preceding DoA episodes. The aims of this work were to characterize the topography of EEG spectral changes prior to DoA episodes and to investigate whether or not behavioral complexity could be predicted by changes in EEG immediately preceding behavioral onsets.

PATIENTS AND METHODS

We collected 103 consecutive video-polysomnographic recordings of 53 DoA adult patients and classified all episodes as simple, rising and complex arousal movements. For each episode, a 5-second window preceding its motor onset ("pre-event") and a 60-second window from 2 to 3 minutes before the episodes ("baseline") were compared. Subsequently, a between-group comparison was performed for the pre-event of simpler versus the more complex episodes.

RESULTS

Spectral analysis over 325 DoA episodes showed an absolute significant increase prior to DoA episodes in all frequency bands excluding sigma, which displayed the opposite effect. In normalized maps, the increase was relatively higher over the central/anterior areas for both slow and fast frequency bands. No significant differences emerged from the comparison between simpler and more complex episodes.

CONCLUSION

Taken together, these results show that deep sleep and wake-like EEG rhythms coexist over overlapping areas before DoA episodes, suggesting an alteration of local sleep mechanisms. Episodes of different complexity are preceded by a similar EEG activation, implying that they possibly share a similar pathophysiology.