Sound analysis of catathrenia: a vocal expiratory sound

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.

Catathrenia in severe obstructive sleep apnea: A novel entity never described before

STUDY OBJECTIVES

Catathrenia, derived from the Greek κατά (kata) meaning below and θρηνώ (threnia) to lament, is characterized by expiratory groaning episodes during sleep. In a case series of nine patients with severe obstructive sleep apnea, we observed a peculiar groaning entity that has not been described before.

METHODS

We described and illustrated the cases with polysomnographic tracings and additional audio recordings.

RESULTS

All patients were men, obese (body mass index 39 ± 6 kg/m2) with an apnea-hypopnea index ranging from 47 to 125/h. In addition, we identified groaning events that were consistently preceded by a cortical arousal associated with a "rescue" respiration after an obstructive hypopnea or apnea. These events exhibited characteristics of "mixed apnea's", but the "central apnea-like part" was a prolonged expiratory groaning phase, with immediately after the terminal expiratory snort appearance of an obstructive apnea. In case the duration of this expiration was at least 10 s we calculated these events separately and the index was 8.4 ± 7.7/h. More rarely (index 0.6 ± 0.5/h) a "central apnea mimicking event" with groaning not followed by an obstruction, was observed. We also observed groaning episodes during expiration with a shorter duration (less than 10 s), not calculated separately. Positive airway pressure, which was well tolerated, eliminated these events.

CONCLUSIONS

This novel catathrenia entity preceded by a cortical arousal and "rescue" respiration in response to obstructive events is intriguing. Possible explanations for these observations are further discussed in this article.

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.

Polysomnographic characteristics and acoustic analysis of catathrenia (nocturnal groaning)

OBJECTIVE

Catathrenia is a sleep disorder characterized by nocturnal groaning sounds emitted during prolonged expiration. As a rare condition, its polysomnographic findings were inconsistent. We aimed to present polysomnographic characteristics of catathrenia patients and perform acoustic analysis of groaning sounds.

APPROACH

Twenty-three patients (eight males and 15 females) diagnosed with catathrenia by video-polysomnography were included. They underwent clinical evaluation and physical examination, and answered a questionnaire. Acoustic analyses (oscillograms and spectrograms) of catathrenia and snoring signals were performed by Praat 6.1.09. Sounds were classified according to Yanagihara criteria.

MAIN RESULTS

The average age of catathrenia patients was 29.6 ± 10.0 years, with a body mass index of 22.3 ± 5.1 kg m^-2. A total of 3728 groaning episodes were documented. Catathrenia events of 16 patients (70%) were rapid eye movement (REM)-predominant. The average duration of groaning was 11.4 ± 4.6 s, ranging from 1.3 to 74.9 s. All signals of groaning were rhythmic or semi-rhythmic, classified as type I and type II, respectively, with formants and harmonics. Snoring events were observed in nine patients. Snoring mainly occurred in the non-REM stage, with a duration of less than 1.5 s. Signals of snoring were chaotic, classified as type III, without harmonics.

SIGNIFICANCE

Catathrenia occurred in all sleep stages but mainly in REM. Durations of groaning varied greatly across patients. Acoustic characteristics of catathrenia were typical. Groaning had rhythmic or semi-rhythmic waveform, formants and harmonics, indicating vocal origin, while snoring had chaotic waveform.

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.

Acoustic Characteristics of Stridor in Multiple System Atrophy

Nocturnal stridor is a breathing disorder prevalent in patients with multiple system atrophy (MSA). An improved understanding of this breathing disorder is essential since nocturnal stridor carries a poor prognosis (an increased risk of sudden death). In this study, we aimed to classify types of stridor by sound analysis and to reveal their clinical significance. Patients who met the criteria for probable MSA and had undergone polysomnography (PSG) were recruited. Patients were then assessed clinically with sleep questionnaires, including the Pittsburgh Sleep Quality Index, and the Hoehn and Yahr scale. Nocturnal stridor and snoring were analyzed with the Multi-Dimensional Voice Program. Nocturnal stridor was recorded in 22 patients and snoring in 18 patients using the PSG. Waveforms of stridors were classified into rhythmic or semirhythmic after analysis of the oscillogram. Formants and harmonics were observed in both types of stridor, but not in snoring. Of the 22 patients diagnosed with stridor during the present study, fifteen have subsequently died, with the time to death after the PSG study being 1.9 ± 1.4 years (range 0.8 to 5.0 years). The rhythmic waveform group presented higher scores on the Hoehn and Yahr scale and the survival outcome of this group was lower compared to the semirhythmic waveform group (p = 0.030, p = 0.014). In the Kaplan Meier's survival curve, the outcome of patients with rhythmic waveform was significantly less favorable than the outcome of patients with semirhythmic waveform (log-rank test, p < 0.001). Stridor in MSA can be classified into rhythmic and semirhythmic types and the rhythmic component signifies a poorer outcome.

HITCal: a software tool for analysis of video head impulse test responses

CONCLUSION

The developed software (HITCal) may be a useful tool in the analysis and measurement of the saccadic video head impulse test (vHIT) responses and with the experience obtained during its use the authors suggest that HITCal is an excellent method for enhanced exploration of vHIT outputs.

OBJECTIVE

To develop a (software) method to analyze and explore the vHIT responses, mainly saccades.

METHODS

HITCal was written using a computational development program; the function to access a vHIT file was programmed; extended head impulse exploration and measurement tools were created and an automated saccade analysis was developed using an experimental algorithm. For pre-release HITCal laboratory tests, a database of head impulse tests (HITs) was created with the data collected retrospectively in three reference centers. This HITs database was evaluated by humans and was also computed with HITCal.

RESULTS

The authors have successfully built HITCal and it has been released as open source software; the developed software was fully operative and all the proposed characteristics were incorporated in the released version. The automated saccades algorithm implemented in HITCal has good concordance with the assessment by human observers (Cohen's kappa coefficient = 0.7).

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.

Sleep related expiratory obstructive apnea in children

STUDY OBJECTIVES

We describe the respiratory, cardiac, and sleep-related characteristics of two types of sleep-related respiratory pauses in children that can fulfill current criteria of pathological apnea, but often seem to be benign: prolonged expiratory apnea (PEA) and post-sigh central apnea (PSCA).

METHODS

All outpatient comprehensive overnight polysomnography completed on children without significant underlying medical conditions completed during an 18-month period were retrospectively reviewed for the presence of augmented breaths followed by a respiratory pause. Events were identified as a PEA or PSCA based on characteristic features. Physiologic parameters associated with the respiratory events were recorded and compared.

RESULTS

Fifty-seven (29 PEA and 28 PEA) events were identified in 17 patients (8.5 ± 3.5 years old). Median durations of PEA and PSCA were not significantly different. For both PEA and PSCA, average heart rate (HR) during the augmented breath before the respiratory pause differed from lowest instantaneous HR during the first half of the pause. When compared to each other, the lowest instantaneous HR recorded in the first half of PEA was lower than that for PSCA (63.9 [59.41-68.3] vs 66.75 [61.7-80.75]) beats per min, p = 0.03. No PEA or PSCA event was associated with an oxygen desaturation more than 3% from baseline.

CONCLUSION

PEA and PSCA have stereotypic HR changes and resemble pathologic apneas but appear to be benign. Clinical significance of PEA and PSCA is yet to be determined. Consistent recognition of the events is required, given their frequency of occurrence and potential for misclassification.

Acoustic characteristic of catathrenia and snoring: different subtypes of catathrenia

OBJECTIVE

Catathrenia (nocturnal groaning) is a rare condition characterized by monotonous irregular sounds that occur during sleep. Not infrequently, catathrenia has been confused with expiratory snoring. We aimed to clarify the subtypes of catathrenia and differentiate them from snoring using sound analyses.

METHODS

We enrolled five patients with catathrenia who were confirmed by overnight polysomnography (PSG). They underwent clinical and physical evaluation, including craniofacial and oromandibular examination, and fulfilled sleep-related questionnaires. Catathrenia and snoring of patients were analyzed acoustically with a Multi-Dimensional Voice Program.

RESULTS

All subjects were young (mean 31.0 years, 22-39) and slim (mean 20.5 kg/m(2) body mass index) women. PSG findings showed normal ranged apnea-hypopnea indices (mean 0.8±1.4/h), respiratory disturbance indices (2.6±1.7/h), and well-preserved sleep architecture. The number of catathrenia during PSG varied between one and 55 per patient, with sound duration ranging from 0.3 to 15.1 s. Of a total of 113 episodes, 70 (61.9%) occurred during REM sleep and 43 (38.1%) during NREM sleep. All patients showed light snoring through the PSG night. In the sound analysis three patients demonstrated monotonous sinusoidal catathrenia sounds, which were of normal ranged fundamental frequency. The other two had sawtooth-shaped catathrenia signals with higher fundamental frequency. In contrast, snoring had an irregular signal in all patients.

CONCLUSIONS

We observed that catathrenia had morphologic regularity, with two types of sound pitches, and snoring had a different signal from catathrenia by sound analysis.

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.