STATE OF BIOELECTRICAL ACTIVITY OF THE BRAIN IN PATIENTS WITH SNORING
DOI:
https://doi.org/10.37219/h3szga49Keywords:
snoring, obstructive sleep apnea, central sleep apnea, electroencephalography, brain bioelectrical activity, diencephalic-brainstem structures, hyperventilation testAbstract
Background: Obstructive sleep-related breathing disorders (SRBD) and snoring represent a significant medico-social issue, substantially increasing the risk of traffic accidents and occupational injuries, while imposing a heavy economic burden. In clinical practice, the verification of central sleep apnea (CSA) – the genesis of which is directly linked to central nervous system pathology – poses particular challenges. Unlike routine diagnostics of obstructive events, CSA cases are often established solely through instrumental screening without a proper evaluation of the underlying pathophysiological mechanisms and neurofunctional changes driving this phenomenon.
Objective: The aim of the study was to investigate the features of the neurofunctional state and bioelectrical activity of the brain using electroencephalography in patients with snoring complicated by episodes of central sleep apnea to elucidate the central mechanisms of this pathology.
Materials and Methods: A total of 101 patients with snoring and 15 somatically healthy controls were examined. Depending on the nature of their respiratory disorders, the patients were divided into two groups: Group 1 (comparison group) comprised 53 individuals with isolated obstructive sleep apnea (OSA); Group 2 (main group) included 48 patients with a verified mixed form of apnea, in whom CSA episodes were recorded concurrently with obstructive ones. The respiratory status was evaluated via overnight cardiorespiratory monitoring using the Somnocheck Micro system (Löwenstein Medical, Germany). Electroencephalographic (EEG) examinations were performed using the "DX-Systems" complex (Ukraine) with qualitative (visual-graphic) and quantitative spectral analysis. Statistical analysis was carried out using Fisher's exact test via angular transformation (φ*).
Results and Discussion: Expert evaluation of native EEGs revealed significant differences in cerebral bioelectrical activity in patients with snoring compared to the control group. In Group 2 (with a central apnea component), the following patterns were recorded with a statistically significant higher frequency: absence of the activation response to eye opening (56.3% vs. 37.7% in Group 1, (p < 0.05), diffuse desorganization and desynchronization of the main cortical rhythms (89.5% vs. 67.9%, (p < 0.05)), and hypersynchronization phenomena (37.5% vs. 22.6%, (p < 0.05)).
The most pronounced intergroup differences (p < 0.01) were found in the rates of overall EEG amplitude reduction (54.1% in Group 2 vs. 28.3% in Group 1) and signs of diencephalic-brainstem structure irritation (68.8% vs. 45.3%). The hyperventilation test proved particularly indicative, provoking an exacerbation of pathological and paroxysmal activity in 77.1% of patients with central apnea compared to 34.0% in the isolated OSA group (p < 0.01). This underscores the extreme sensitivity of their limbic-diencephalic complex to fluctuations in blood gas composition amid chronic nocturnal hypoxia. The detection rate of "acute wave – slow wave" complexes in Group 2 was 43.8% versus 28.4% in Group 1 (p < 0.05). Concurrently, the prevalence of limbic-diencephalic irritation signs and flattened zonal differences was comparable between both groups (p > 0.05), proving the universal nature of these impairments under respiratory stress.
Conclusions
1. Patients with snoring present with pronounced impairments in cerebral bioelectrical activity, manifested by a statistically significant (p < 0.05) increase in the frequency of rhythm desorganization, flattened zonal differences, suppression of the activation response, and an elevated slow-wave activity index with an amplitude accent in the frontal and occipital leads.
2. Neurofunctional impairments demonstrate a distinct pathogenic differentiation: in patients with a central sleep apnea component, destructive EEG changes are substantially deeper and more widespread than in patients with isolated obstructive sleep apnea.
3. The presence of diencephalic-brainstem irritation signs, a generalized reduction in EEG amplitude, exacerbation of pathological activity during the hyperventilation test, an increased slow-wave activity index, and the presence of "acute wave – slow wave" complexes serve as objective prognostic markers for the development of central sleep apnea.
References
1. Pataka A, Kotoulas S, Kalamaras G, Schiza S, Sapalidis K, Giannakidis D, et al. Gender differences in obstructive sleep apnea: the value of an integrated health-related quality of life approach. J Clin Med. 2020;9(1):130. doi: 10.3390/jcm9010130.
2. Abbasi A, Gupta SS, Sabharwal N, Meghrajani V, Sharma S, Kamholz S. A comprehensive review of obstructive sleep apnea. Sleep Sci. 2021;14(2):142–154. doi: 10.5935/1984-0063.20200056.
3. McNicholas WT, Bonsigore MR. Obstructive sleep apnoea as a multisystem disease. Eur Respir Rev. 2022;31(164):210261. doi: 10.1183/16000617.0261-2021.
4. Lv R, Bao F, Chen G, et al. Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome. Signal Transduct Target Ther. 2023;8:229. doi: 10.1038/s41392-023-01496-3.
5. Randerath W, Bassetti CLA, Bonsignore MR, et al. Central sleep apnoea: not just one phenotype. Eur Respir Rev. 2024;33(171):230171. doi: 10.1183/16000617.0171-2023.
6. Kasurak E, Randerath W, Hedner J, Grote L, Bonsignore MR, et al. Gender differences in obstructive sleep apnea with comorbid depression and anxiety. Sleep Breath. 2023;27(2):789–797. doi: 10.1007/s11325-022-02689-1.
7. Imen T, Wanberg LJ, Ayeb J, Bouchareb S. Prevalence of sleepiness and associations with quality of life in obstructive sleep apnoea. ERJ Open Res. 2021;7(4):00543-2021. doi: 10.1183/23120541.00543-2021.
8. Benjafield AV, Ayas NT, Eastwood PR, Heinzer R, Ip MSM, Morrell MJ, et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir Med. 2019;7(8):687–698. doi: 10.1016/S2213-2600(19)30198-5.
9. Roberts EG, Owens RL. The pathogenesis of central and complex sleep apnea. Curr Neurol Neurosci Rep. 2022;22(5):215–223. doi: 10.1007/s11910-022-01199-2.
10. Zheng Y, Xie Y, Pépin JL. Management of central sleep apnoea: a review of non-hypercapnic causes. Breathe. 2024;20(3):230235. doi: 10.1183/20734735.0235-2023.
11. Zin DM. [Assessment of the impact of snoring and obstructive sleep apnea on patients' quality of life: results of a questionnaire-based study]. Otorhinolaryngology. 2025;6(8):52-57. doi: 10.37219/2528-8253-2025-6-52. [Article in Ukrainian].
12. Zin D, Shydlovska T. Drug-induced sleep endoscopy as an effective diagnostic tool for obstructive sleep apnea. Ukrainian Scientific Medical Youth Journal. 2025;3(157):25-31. doi: 10.32345/USMYJ.3(157).2025.25-31. [Article in Ukrainian].
