Catathrenia (nocturnal groaning): an abnormal respiratory pattern during sleep

The clinical characteristic of catathrenia: a new look at an old issue-a systematic review of existing literature

STUDY OBJECTIVES

The International Classification of Sleep Disorders categorized catathrenia as a respiratory disorder, but there are doubts whether episodes appear during rapid eye movement (REM) sleep or the non-rapid eye movement (NREM), their duration, and symptoms. The main objectives were to identify the most common features and relations of catathrenia.

METHODS

PubMed, Embase, and Web of Science were searched according to the PRISMA 2020 guidelines. The Joanna Briggs Institute and the ROBINS-I tools were chosen to assess the risk of bias.

RESULTS

A total of 288 records were identified, 31 articles were included. The majority of the studies had a moderate risk of bias. 49.57% of episodes occurred during the NREM sleep, while 46% took place during REM. In 60.34% females, catathrenia was more common in the NREM, while in 59.26% of males was in REM sleep (p < 0.05). Females and obese individuals were found to have shorter episodes (p < 0.05). Age was inversely correlated with minimal episodes duration (r =  - 0.34). The continuous positive airway pressure (CPAP) therapy was inversely correlated with the maximal episode duration (r =  - 0.48).

CONCLUSIONS

Catathrenia occurs with similar frequency in both genders. The most frequent symptoms embraced groaning, awareness of disturbing bedpartners, and daytime somnolence-not confirmed by the Epworth Sleepiness Scale. The episodes occur more frequently in NREM than in REM sleep. Catathrenia may be considered as a sex-specific condition. The effects of CPAP treatment leading to shortening episodes duration, which may indicate the respiratory origin of catathrenia.

Lamentations in the night: A systematic review on catathrenia

Catathrenia is a loud expiratory moan during sleep that is a social embarrassment and is sometimes confused with central apnea on polysomnography. It affects about 4% of adults, but cases are rarely referred to sleep centers. Catathrenia affects males and females, children and adults, who are usually young and thin. A "typical" catathrenia begins with a deep inhalation, followed by a long, noisy exhalation, then a short, more pronounced exhalation, followed by another deep inhalation, often accompanied by arousal. The many harmonics of the sound indicate that it is produced by the vocal cords. It is often repeated in clusters, especially during REM sleep and at the end of the night. It does not disturb the sleepers, but their neighbors, and is associated with excessive daytime sleepiness in one-third of cases. The pathophysiology and treatment of typical catathrenia are still unknown. Later, a more atypical catathrenia was described, consisting of episodes of short (2 s), regular, semi-continuous expiratory moans during NREM sleep (mainly in stages N1 and N2) and REM sleep, often in people with mild upper airway obstruction. This atypical catathrenia is more commonly reduced by positive airway pressure and mandibular advancement devices that promote vertical opening.

Ultrasonic vocalisations during rapid eye movement sleep in the rat

Rats are known to use a 22-kHz ultrasonic vocalisation as a distress call to warn of danger to other members of their group. We monitored 22-kHz ultrasonic vocalisation emissions in rats (lean and obese) as part of a sleep deprivation study to detect the eventual presence of stress during the procedure. Unexpectedly, we detected ultrasonic vocalisation emission during rapid eye movement (REM) sleep, but not during non-REM (NREM) sleep, in all the rats. The event occurs during the expiratory phase and can take place singularly or as a train. No difference was detected in the number or duration of these events in lean versus obese rats, during the light versus the dark period, and after sleep deprivation. As far as we know, this is the first report showing that rats can vocalise during REM sleep.

Catathrenia in children: clinical presentation, polysomnographic features, natural history, and response to therapy

STUDY OBJECTIVES

To determine the clinical presentation, polysomnographic appearance, and the response to therapy of catathrenia in children.

METHODS

A retrospective analysis was performed in children referred or evaluated at the Boston Children's Hospital Sleep Center between 1998 and 2021 who were documented to have catathrenia either as a chief complaint or an incidental finding.

RESULTS

Catathrenia was identified in 21 children. The age of onset by parent report was 6.4 ± 4.4 years (range: birth-14 years), but the diagnosis was at 8.3 ± 3.8 years (range: 1.5-14 years). Catathrenia was the chief complaint for 24% of patients and was incidentally identified in 76% referred for breathing concerns. Bruxism was observed in 62% of patients. Catathrenia events most often occur following an electrocortical arousal (79%) and are most common in the second half of the night (73%). Catathrenia was observed exclusively in rapid eye movement (REM) sleep (16%), exclusively in non-REM sleep (32%), and in both sleep states (52%). Treatment of obstructive sleep apnea resulted in resolution or improvement in the obstructive sleep apnea in all patients, but the catathrenia persisted at a reduced level.

CONCLUSIONS

Most catathrenia in children is diagnosed incidentally during evaluation for sleep-disordered breathing, although the groaning often started many years earlier. Catathrenia events decreased considerably after treatment of obstructive sleep apnea, but persisted in all patients. Catathrenia was also observed in children without signs or symptoms of sleep-disordered breathing, indicating that these are distinct conditions. The majority of children with catathrenia had no sleepiness or behavioral concerns.

CITATION

Katz ES, D'Ambrosio C. Catathrenia in children: clinical presentation, polysomnographic features, natural history, and response to therapy. J Clin Sleep Med. 2023;19(8):1505-1511.

Tracheal Sound Analysis

Tracheal sound sensors provide multiple respiratory signals that are valuable for studying upper airway characteristics. This chapter reviews the original work and ongoing research on tracheal sound analysis in relation to upper airway obstruction during sleep. Past and current research suggest that being associated with other sleep study recording sensors and advanced signal processing techniques, tracheal sound analysis can extensively contribute to the diagnosis and assessment of sleep-disordered breathing.

Mandibular advancement device as treatment trial for catathrenia (nocturnal groaning)

STUDY OBJECTIVES

Catathrenia is a rare disease, classified as isolated symptoms and normal variants under sleep-related breathing disorders in the International Classification of Sleep Disorders, third edition. Because of its rarity, the research on its pathogenesis and treatment is insufficient. This study aimed to evaluate whether the mandibular advancement device (MAD) could be considered an alternative treatment trial and if so, to explore factors predicting its effectiveness.

METHODS

Thirty patients (12 males and 18 females, aged 16 to 67 years) with catathrenia participated in the study. They underwent standard clinical evaluation, questionnaires, physical examinations, craniofacial evaluations, video-polysomnography, and imaging of the upper airway before and after the insertion of the MAD. Groaning index (GI, groaning episodes per hour of sleep) and apnea-hypopnea index (AHI) were evaluated and anatomic factors predicting effectiveness were explored.

RESULTS

The sleep efficiency of most patients was higher than 80% and groaning was present throughout all stages of sleep. With the insertion of MAD, GI decreased significantly from 5.8 (2.7, 14.3) to 2.8 (1.3, 12.2) events/h (P = 0.014). Age had a negative effect on efficacy. Mandibular repositioning of MAD, especially the amount of vertical opening and changes of cross-sectional area of hypopharynx, was positively related with efficacy.

CONCLUSIONS

The MAD could be considered a possible treatment trial for those seeking treatment for groaning.

CLINICAL TRIAL REGISTRATION

Registry: Chinese Clinical Trial Registry; Identifier: ChiCTR-COC-17013239; URL: http://www.chictr.org.cn/showproj.aspx?proj=22286.

Catathrenia and Treatment With Positive Airway Pressure in the Pediatric Population

None

Catathrenia, also known as sleep-related groaning, is a relatively rare sleep disorder with characteristics consistent with loud groaning on expiration during sleep. Organic causes of catathrenia are unknown and the decision of whether or not to treat is unclear. Limited research is available concerning appropriate treatment and none of the literature focuses primarily on pediatrics. We report a series of three, male pediatric cases with catathrenia that were treated with continuous positive airway pressure (CPAP) while identifying and comparing clinical symptoms, polysomnogram findings, treatment, and patient response to treatment. Catathrenia may be associated with abnormal nocturnal oxygenation and ventilation and may lead to negative clinical daytime symptoms which may warrant treatment. If catathrenia leads to sleep disruption and negative daytime symptoms, treatment with CPAP should be considered.

Catathrenia (Nocturnal Groaning): A Social Media Survey and State-of-the-Art Review

STUDY OBJECTIVES

Catathrenia is an underrecognized nocturnal vocalization phenomenon that can be a source of perplexity to patients, bed partners, and medical providers. Catathrenia is distinct from both sleep talking (a parasomnia with loud talking during sleep) and snoring (noise due to vibration of upper airway soft tissues related to variations in airway resistance). The objective of this review is to provide an evidence-based resource to help the practitioner reliably evaluate and manage patients with this condition.

METHODS

Data were gathered from: (1) PubMed, Scopus, Web of Science, and Google Scholar; and (2) catathrenia social media groups (Yahoo and Facebook).

RESULTS

Data collected were (1) 15 case reports and 17 case series describing 191 patients with catathrenia; (2) questionnaires from 47 catathrenia subjects; (3) 5 audio files.

CONCLUSIONS

Catathrenia is a noise produced during sleep (distinct from snoring) with identifiable harmonics, a computable main frequency, and high-decibel intensity that involves active adduction and vibration of the vocal cords during expiration. The quality of groaning in catathrenia is monotone, and often presents with a morose or sexual connotation, causing a significant social problem for patients. Although there is no association with risk of physical harm, catathrenia does present a significant disturbance to the bed partner and has been associated with subjective impairments to sleep quality, including unrefreshing sleep and fatigue. Polysomnography can be useful if performed properly to confirm the diagnosis and to evaluate for comorbid sleep disturbances, such as obstructive sleep apnea or parasomnia. Directions for further research could involve consideration of deep breathing exercises, yoga, meditation, or myofunctional therapy to help abate symptoms.

Catathrenia, a REM predominant disorder of arousal?

OBJECTIVES

Catathrenia is an uncommon and poorly understood disorder, characterized by groaning during sleep occurring in tandem with prolonged expiration. Its classification, pathogenesis, and clinical relevance remain debated, substantially due to the limited number of cases reported to date. We report a series of consecutive cases of catathrenia, their clinical and polysomnographic characteristics, and their subsequent management.

METHODS

Consecutive patients with catathrenia who had undergone full polysomnography in our institution over a 5.5-year period were included. Catathrenia events (CEs) were examined in clusters, which formulated catathrenia periods (CPs). The relationships between CPs, sleep stage distribution, electroencephalogram (EEG) arousals, and other sleep parameters were assessed, along with the clinical presentation and management of catathrenic patients.

RESULTS

A total of 427 CPs were identified in 38 patients, 81% arising from rapid eye movement (REM) sleep. EEG arousals preceded or coincided with the onset of 84% of CPs, which were of longer duration than those not associated with an arousal (57.3 ± 56.8 vs. 32.2 ± 29.4 s, p < 0.001). Each CE had a characteristic airflow signal, with inspiration preceding a protracted expiration and a brief more rapid exhalation, followed by deep inspiration. Although the majority of patients were referred on the basis of bed partner complaints, 44.7% complained of daytime sleepiness. Continuous positive airway pressure therapy and sleep-consolidating pharmacotherapy led to subjective improvement, but were limited by poor long-term adherence.

CONCLUSIONS

In the largest series of catathrenia patients reported to date, we found that this rare disorder is characterized by a distinct breathing pattern and arises predominantly from REM sleep, with arousals almost uniformly preceding or coinciding with the onset of CPs.

Anatomical characteristics of catathrenia (nocturnal groaning) in upper airway and orofacial structures

BACKGROUND

Catathrenia is a rare sleep disorder characterized by repeated groaning in a protracted expiration preceded by a deep inspiration. This study aimed to explore whether anatomy is one of pathophysiology of catathrenia by investigating the anatomical features associated with catathrenia in the upper airway, craniofacial structures, and dental patterns.

MATERIAL AND METHODS

Twenty-two patients with catathrenia (7 males, 15 females; age 22 to 69 years) were recruited as well as 66 patients matched by age and gender (matching proportion 1:3) with obstructive sleep apnea syndrome (OSAS). Both groups underwent cephalograms and dental casting, and cephalometric measurements and the Peer Assessment Rating (PAR) index was applied. Differences between the two groups were evaluated and cephalometric measurements in catathrenia group were compared with control values of Chinese patients from previous studies.

RESULTS

As for airway-related measurements, increased PNS-R, PNS-UPW, and H-FH and decreased SPT and TGL were found in catathrenia group compared to normal values. Such trends were found even more evident when compared with the OSAS Group. As for craniofacial parameters, values of U1/NA and U1/SN were found increased in the catathrenia group compared with normal values and values of MP/FH and Y decreased. The differences were more distinct from the OSAS Group. Increased arch lengths and upper inter-first molar widths, and decreased overbite and PAR index, were found in catathrenia group compared with the OSAS Group.

CONCLUSION

Catathrenia patients present with a broad upper airway, yet protrusive upper incisors and flat mandibular angles. Anatomical characteristics of catathrenia are different from those associated with OSAS, namely a wide airway, large skeleton, and good occlusion.

Catathrenia: respiratory disorder or parasomnia?

BACKGROUND

The International Classification of Sleep Disorders-Third Edition (ICSD-3) classifies catathrenia among the respiratory disorders and not as a parasomnia as in ICSD-2. Few patients have been reported during these years, and the clinical description of the sound is different from group to group. In fact, there is no full agreement about its nature, origin, meaning, and treatment.

METHODS AND RESULTS

In this paper we review the literature on catathrenia focusing on the characteristics of the sound, demographics of the patients, aetiology, response to treatment, etc., in order to support its classification as a respiratory disorder or a parasomnia. We also discuss the possibility of Catathrenia being not one disorder but two variants or two different disorders.

Professor Elio Lugaresi's contributions to neurology and sleep disorders

The authors present a brief historical review of the most important contributions by Professor Elio Lugaresi, of the University of Bologna, Italy, to neurology and sleep disorders.

Sleep-related groaning: prevalence and characteristics in a cohort of patients with suspected obstructive sleep apnea

CONCLUSION

Nocturnal groaning has the same prevalence in patients referred for diagnosis of sleep-disordered breathing as among other populations referred for sleep studies. The respiratory tracings in these patients have a distinct appearance that is possible to recognize with a polygraphic recording and thereby prevent the pattern from being misdiagnosed as central apneas.

OBJECTIVES

The aim of this study was first to estimate the prevalence of groaning in patients referred for diagnosis of sleep-related breathing disorders. Second, we wanted to describe the respiratory pattern in order to distinguish the patients from patients with sleep apnea.

METHODS

This was a prospective study in 1004 patients, performed in the Sleep Unit in our ENT Department, during a 12 month period.

RESULTS

Four patients were diagnosed with video polysomnography, and the diagnosis of nocturnal groaning was confirmed. The prevalence of groaning in our sleep laboratory was 0.4%. All the patients had a mild form of sleep-related disturbance, and all groaning episodes occurred during REM sleep. The groaning events appeared in clusters. The length of each groan varied between 4 and 38 s. The number of events in a period varied between 2 and 11, and the length of each groaning period ranged between 11 and 168 s.

Nocturnal moaning and groaning-catathrenia or nocturnal vocalizations

PURPOSE

Descriptions of nocturnal vocalizations, including catathrenia, are few. We undertook a study at our center on patients diagnosed with catathrenia, to evaluate the characteristic features of these events and their response to continuous positive airway pressure (CPAP) treatment.

METHODS

Retrospective study of patients with a diagnosis of catathrenia who had an overnight polysomnogram (PSG) and available synchronized audio video recordings (to confirm the presence of moaning and groaning), at our center between January 2007 and May 2010.

RESULT

Ten patients were included in the analysis. Three (30%) patients presented with the chief complaint of expiratory noises during sleep. The other moaning/groaning sounds were incidental findings noted by the sleep technologist and/or the sleep physician. The number of moaning/groaning events during PSG varied between 2 and 343 per patient with sound duration ranging from 0.4 to 21.4 s. Moaning/groaning events during exhalation (1,026 episodes) were separated into typical catathrenia events (as per the International Classification of Sleep Disorders, 2nd edition [ICSD-2] definition) and atypical/nocturnal vocalization events (moaning/groaning events that did not meet the ICSD-2 criteria). Typical catathrenia events (5% or 52/1,026) were experienced by five of the ten patients and had mean exhalation duration of 14.97 ± 5.13 s (range 5.8-24 s) with a mean sound duration of 8.47 ± 5.97 s (range 2-21.4 s). The typical and atypical events occurred predominantly in NREM sleep. Six of the ten patients had associated sleep-disordered breathing and four underwent CPAP titration. All four patients had significantly fewer events of moaning/groaning (mean reduction was 75.8 ± 26.2%) with CPAP.

CONCLUSION

New and unique features were identified in our series of patients diagnosed with catathrenia. Though all events had the characteristic moaning and groaning sound during exhalation, only a small percentage (5%) met the catathrenia definition as outlined in ICSD-2. Do we label the atypical events as part of the spectrum of nocturnal vocalizations or consider them as catathrenia by redefining the criteria? CPAP appeared to be a reasonable treatment option.

Treatment options for parasomnias

Parasomnias are undesirable physical or experiential events that occur in and around sleep. Treatments include reassurance in some cases, various forms of cognitive-behavioral therapy (CBT), and pharmacologic agents. Cognitive restructuring, imagery rehearsal, relaxation, hypnosis, desensitization, and anticipatory awakenings are some of the common CBT and nonpharmacologic interventions. Medications that are used belong to a wide variety of pharmacologic classes, such as alpha-blockers (prazosin), tricyclic antidepressants (imipramine and clomipramine), selective serotonin reuptake inhibitors, benzodiazepines (diazepam and clonazepam), anticonvulsants (topiramate and gabapentin), desmopressin acetate, and anticholinergic agents (oxybutynin and tolterodine). Data on efficacy are only available from randomized trials on CBT and prazosin for nightmares and on pharmacologic and alarm therapy for enuresis. No large-scale randomized trials are available to assess the efficacy of the other treatments, and most data come from anecdotal case reports, case series, or small open-label trials.