Sleep Assessment in Patients with Inner Ear Functional Disorders: A Prospective Cohort Study Investigating Sleep Quality Through Polygraphy Recordings

Abstract

Background/Objectives: The vestibulo-respiratory reflex regulates the tension of the respiratory muscles, which prevents apneas and awakenings during sleep. This study aimed to determine whether functional deficits in the inner ear disturb sleep quality. Methods: We compared sleep parameters in patients with their first episode of acute inner ear deficit (Group A: sudden idiopathic vertigo attack, sudden sensorineural hearing loss), chronic functional inner ear impairment (Group B: chronic peripheral vertigo, permanent hearing loss), and in healthy individuals (Group C). Polygraphy recordings were performed twice, in Group A at the onset of acute otoneurological symptoms and the second time after their withdrawal with an interval of 1 to 13 days, in Group B after 1 to 6 days, and in Group C after 1 to 8 days. Results: In Group A during the symptomatic night, overall and central apnea-hypopnea indices were significantly higher and snoring time was longer. Group A also had higher central apnea-hypopnea index on the first night compared to healthy individuals. In chronic disorders, sleep recordings showed lower autonomic arousal index than in controls or symptomatic nights in Group A. Conclusions: These findings highlight the severity of sleep apnea indicators in Group A. Our results suggest that acute dysfunction of the inner ear substantially impacts central neuronal signaling responsible for regulating normal sleep-related breathing and leads to a deterioration in sleep quality in contrast to individuals with chronic inner ear impairments. It can also be assumed that people with chronic vertigo or hearing loss experience less interrupted sleep than healthy individuals.

Keywords: apnea; breathing; labyrinth; perception; wakefulness.

Figure 1

Statistics of recorded sleep parameters: (a) AHI, apnea-hypopnea index; (b) cAHI, central apnea-hypopnea index; (c) oAHI, obstructive apnea-hypopnea index; (d) AAI, autonomic arousal index; (e) AAIre, autonomic arousal index related to respiratory events; (f) RERA, respiratory effort-related arousal index; 1, first night, 2, second night measurement; A, Group A—acute idiopathic functional inner ear disease, B, Group B—chronic functional inner ear disease, C, Group C—healthy controls. box: 25–75%, whisker: non-outlier range, □ median, ° outliers, • extreme outliers, * p < 0.05.