Elsevier

Sleep Medicine

Volume 2, Issue 1, January 2001, Pages 19-30
Sleep Medicine

Original article
Vocalization during episodes of prolonged expiration: a parasomnia related to REM sleep

https://doi.org/10.1016/S1389-9457(00)00039-3Get rights and content

Abstract

Objective: We report on a sleep-related respiratory dysrhythmia that is characterized by episodes of bradypnea associated with vocalization.

Background: To date, many parasomnias with affinity for NREM sleep, REM sleep or both sleep states have been identified. While the reported clinical syndrome may resemble these known parasomnias, different clinical features are pointed out.

Methods: Ten patients (seven males and three females) aged between 20 and 49 years, were included. All patients underwent standard clinical examinations and full polysomnography.

Results: The principal complaint was unusual sound-making during sleep. Polysomnography demonstrated the presence of clustered bradypneic events associated with prolonged expiration and expiratory sound production. Replay of the sound signal revealed monotonous vocalization, consistent with groaning. These episodes occurred predominantly during REM sleep. Repeated sleep studies showed a remarkably constant night-to-night consistency of these vocalization episodes. Medical and neurological examinations disclosed no particular abnormalities, except in one patient, in whom a frontal meningioma was detected. Different empirical treatments, including pharmacotherapy and nasal continuous positive airway pressure therapy, provided insufficient symptomatic control.

Conclusions: The syndrome described above clearly has distinct features with respect to well-defined sleep disorders, such as central sleep apnea syndrome and somniloquy. Therefore, it is proposed as a separate nosological entity.

Introduction

The term ‘parasomnia’ refers to clinical disorders that are not related to abnormalities of the sleep/wake processes per se, but that are characterized by undesirable physical phenomena occurring predominantly during sleep [1]. To date, many parasomnias with affinity for NREM sleep, REM sleep or both sleep states have been identified. In the International Classification of Sleep Disorders (ICSD, 1990) sleeptalking (somniloquy), sleep terrors (pavor nocturnus), REM sleep behavior disorder are listed as separate diagnostic entries [2]. In the present article, we report on a sleep-related respiratory phenomenon that has features in common with the syndromes mentioned above, that also may be confused with central sleep apnea, but still is distinct on several points. Polysomnography (PSG) typically reveals bradypneic events that tend to cluster and are most prevalent during REM cycles in the latter part of nocturnal sleep. These bradypneas consist of a deep inspiration, followed by prolonged expiration and expiratory monotonous vocalization. In order to support our hypothesis that a specific nosological entity is involved, we report here all pertinent information on this new parasomnia, including the clinical records, the results of descriptive statistical analyses, differential diagnosis and outcomes of therapeutic interventions.

Section snippets

Methods

During a 3-year period, 1836 subjects presenting with various kinds of sleep disorders were studied in our sleep laboratory, which is part of a multidisciplinary sleep disorders center operating in a university hospital setting. The diagnostic work-up of all patients comprised administration of a 91-item sleep questionnaire, medical history, general clinical examination, and full PSG including video-recording of sleep. The parasomnia that is subject of the present article was detected in ten

Clinical records

To date, we have identified ten patients of caucasian race (seven males and three females) showing the particular sleep-related disorder that is subject of the present study. This patient group represents 0.54% of the population admitted to the sleep lab during the 3-year observation period. Their clinical records, including medical history and neurological examination, are summarized in Table 1, Table 2. All patients denied the presence of sleep paralysis, sleep onset hallucinations and

Discussion

The clinical hallmark of the sleep disorder described in this article is nocturnal vocalization. The vocal noise produced by the patients is reported to be loud, to occur on a regular basis and to be of serious annoyance to room-mates or bed partners, at whose instigation medical attention may be sought. The first symptoms typically appear during adolescence or early adulthood. The history is not suggestive of an inherited pattern. Although patients are usually unaware of their breathing

Acknowledgments

We are indebted to M. Neyens for the scoring of sleep studies; F. De Poorter for patient care; Dr R. Deman for referring one of the patients; Professor G. Bullock for review of English grammar. We express our special appreciation to Dr John W. Shepard, Jr, M.D. and Dr Michael Silber, M.D. (Mayo Clinic, Rochester, MN, USA) for review of some polysomnographic data and expert advice. This research was supported by the Flemish Fund for Scientific Research (FWO grant no. 3.0092.93).

References (15)

  • R.D Hamilton et al.

    The effect of lung inflation on breathing in man during wakefulness and sleep

    Respir Physiol

    (1988)
  • A Rechtschaffen et al.

    A manual of standardized terminology, techniques and scoring system for sleep stages of human subjects

    (1968)
  • EEG arousals: scoring rules and examples

    Sleep

    (1992)
  • J De Roeck et al.

    Sleep-related expiratory groaning: a case report [abstract]

    Sleep Res

    (1983)
  • A.M Arkin

    Sleep-talking: a review

    J Nerv Ment Dis

    (1966)
There are more references available in the full text version of this article.

Cited by (75)

  • Catathrenia: sleep related groaning

    2023, Encyclopedia of Sleep and Circadian Rhythms: Volume 1-6, Second Edition
  • Catathrenia, a REM predominant disorder of arousal?

    2017, Sleep Medicine
    Citation Excerpt :

    Apneas and hypopneas were scored following standard AASM definitions to determine the apnea–hypopnea index (AHI) [21]. In line with previous reports [2], a CE was defined as a deep inspiration followed by a prolonged expiration, frequently associated with monotonous vocalization resembling groaning, which was followed by a brief expiration and a deep inspiration (Fig. 1). These breathing events were frequently, but not uniformly, associated with groaning noises of varying amplitudes (Supplementary Videos S1 and S2).

  • Catathrenia: Respiratory disorder or parasomnia?

    2015, Sleep Medicine
    Citation Excerpt :

    In the ICSD-2, catathrenia was included in ‘other parasomnias’, but in other studies it has been indicated that it occurs predominantly during REM sleep. Most of the authors have supported this opinion, including Pevernagie and Oldani [2,20]. According to Pevernagie et al. [2], in fig. 3B on p. 27, long and more pronounced bradypnoeic events occur exclusively during REM sleep and the index of bradypnoeic events seems to increase with consecutive REM cycles, not with the NREM cycles.

View all citing articles on Scopus
View full text