The Auditory System in Sleep

Rev Neurol. Sep ;41(5) [The auditory system in sleep]. [Article in Spanish]. Velluti RA(1), Pedemonte M. Author information: (1)Neurofisiología.
Table of contents

Obstructive sleep apnea causes changes in normal sleep architecture, fragmenting it chronically with intermittent hypoxia, leading to serious health consequences in the long term. It is believed that the occurrence of respiratory events during sleep, such as apnea and hypopnea, can impair the transmission of nerve impulses along the auditory pathway that are highly dependent on the supply of oxygen. However, this association is not well established in the literature. To compare the evaluation of peripheral auditory pathway and brainstem among individuals with and without obstructive sleep apnea.

The sample consisted of 38 adult males, mean age of The groups were classified based on polysomnography in: All study subjects denied a history of risk for hearing loss and underwent audiometry, tympanometry, acoustic reflex and Brainstem Auditory Evoked Response.


  • [The auditory system in sleep]..
  • Stonewall: Stories of Gay Liberation.
  • Services on Demand.
  • Payback!
  • The Philosophical View of the Great Perfection in the Tibetan Bon Religion (Tibetan Bon Philosophy)?
  • .

There was no difference between the groups for hearing thresholds, tympanometry and evaluated Brainstem Auditory Evoked Response parameters. The presence of obstructive sleep apnea is associated with changes in nerve conduction of acoustic stimuli in the auditory pathway in the brainstem. The increase in obstructive sleep apnea severity does not promote worsening of responses assessed by audiometry, tympanometry and Brainstem Auditory Evoked Response.

Obstructive sleep apnea OSA is recognized as one of the major causes of morbidity and mortality, and is associated with a wide range of cardiovascular, metabolic, neurological, physiological changes, as well as patient cognitive impairments, and has been considered as one of the major problems of public health.

The possibility of OSA interfering with the process of generation and transmission of nerve impulses in the auditory system is reported by previous studies, but this association is not well established, and there is doubt as to the actual effect of OSA on hearing.

Auditory System: Neuroanatomy Video Lab - Brain Dissections

This study aimed to compare the findings of the evaluation of the peripheral auditory pathways and of the brainstem among individuals with and without OSA. This study was approved by the Institutional Ethics Committee under protocol number 1. The sample consisted of 38 adult males divided into four groups: All subjects underwent polysomnography. The exclusion criteria adopted in the study were: For the investigation of tympanometry, the tympanometry curve of admittance was recorded with a Hz probe tone, and ipsilateral and contralateral acoustic reflex investigation at frequencies of , , and Hz.

Tympanometry and acoustic reflexes evaluations were performed through the Titan equipment Interacoustics, Denmark. The acoustic stimulus used to record BAER was the click with rarefied polarity with Hz high pass filter and Hz low pass monoaurally presented at 80 dBnHL with time of stimulus of 0. The stimulus with condensed polarity was employed in situations where the amplitudes of the responses showed to be reduced, allowing the selection of the best route of waves for analysis.

Two tracings were recorded to ensure wave reproducibility. BAER results were classified as normal or abnormal on each side of the ear. Models of analysis of variance ANOVA of 3 factors 13 for audiometry and ipsilateral and contralateral acoustic reflexes were used.

In the models, the factors disease group Group , ear side Ear and Frequency were considered, with the latter two factors being considered with repeated measures. Due to the large number of descriptive levels associated with the Frequency factor, the correction proposed by Greenhouse-Geisser was applied. For multiple comparisons the method proposed by Holm was used. To verify the association between the degree of OSA severity and the number of ears with responses out of normal standard for latencies I, III and V, and interpeak I-V, a nonparametric chi-square test was performed.

Through Fisher's exact nonparametric test, multiple comparisons were performed of the number of ears with responses out of normal standard for latencies I, III and V, and interpeak I-V of BAER of each disease group mild, moderate and severe , confronting them with the control group. All statistical analyses were performed using the R software version 3.

The study included a total of 38 subjects, mean age of The average hearing thresholds did not differ among the groups 0. Furthermore, the values for the ipsilateral acoustic reflexes do not differ among the groups, nor in any other factors analyzed. That is, the average of the frequencies of , and Hz were higher than the average frequency of Hz.

There was no statistical difference for any of the effects of interaction between the factors Group and Ear in the BAER parameters evaluated. There was no significant difference for the main effects of the factors Group and Ear. Thus, for BAER variables, there were no significant differences among the averages of the groups and among the means of the ears. Table 2 shows the percentage of changes found in each group in relation to the absolute latencies of waves I, III, V and interpeak I-V, taking the normal range 12 provided by the equipment used in the study into account.

Considering the degree of severity of OSA, Fisher's exact test found the association between the presence of moderate OSA and the presence of change in absolute latency of wave V. Regarding baseline variables, it is observed that the four study groups are properly matched for age and BMI. The age range of the sample of this study was wide.

The Auditory System in Sleep : Ricardo A. Velluti :

However, many studies involving the hearing of individuals with OSA have also included samples in a similar way 8 , 9 , 16 and even greater than that found in this study 17 - 19 Table 3. Regarding audiometry, no statistical difference in auditory thresholds caused by the presence of OSA was observed. Specifically, a subject of the group with severe OSA had mild hearing loss 20 in the left ear, whose average of hearing thresholds of , and Hz was Moreover, few individuals had low auditory threshold in isolated frequencies: A similar result was observed in another study, 16 in which the presence of low auditory threshold was found, specifically in control subjects without OSA, and also without reporting a history of hearing loss.

Unlike the present study, another study 18 found that individuals at high risk for the presence of OSA had lowered tone thresholds when compared to control.

Unisciti a Kobo e inizia a leggere oggi stesso

However, for the above study, the risk for OSA was assessed through a standardized questionnaire, with no polysomnography diagnosis. Also, the fact that a very wide age range was selected years with the presence of tinnitus may have contributed to the difference in the hearing threshold, since the two factors are strongly related to the manifestation of hearing loss. Regarding tympanometry, the results were considered normal for adults, 23 , 24 probably due to the exclusion criteria adopted in this study. These data did not agree with the findings of the literature where tympanometric curves of types B and C were observed in subjects with moderate and severe degree of OSA.

BAER examination provides objective information that can be considered as parameters for diagnostic purposes, as for the structural and functional integrity of the auditory pathways to the brainstem, being widely used clinically, both because it has well-defined generators, and due to the characteristic of reproducibility. Moreover, considering the multiple comparisons of groups with disease compared to the control, the group with moderate OSA showed an association with change in latency of wave V.

Likewise, the groups with higher severity of OSA, moderate and severe, had greater occurrence of change in interpeak I-V compared to the control. The study shows that individuals with severe hypoxemia or hypercapnia have high prevalence of abnormalities in BAER. Neuroimaging of Sleep and Sleep Disorders. Brain Stimulation in Psychiatry. The Neuronal Codes of the Cerebellum. Functional Neuromarkers for Psychiatry. Plasticity in Sensory Systems. Neuroimaging and Neurophysiology in Psychiatry.

Altri titoli da considerare

Brain Plasticity and Behavior. The Little Black Book of Neuropsychology. Pediatric Traumatic Brain Injury. Windows to the Brain. Textbook of Neural Repair and Rehabilitation: Volume 2, Medical Neurorehabilitation. The Neurology of Consciousness. Paediatric Biomechanics and Motor Control. Mark De Ste Croix. Clinical Neurophysiology in Disorders of Consciousness. The Auditory System in Sleep. The Biology of Desire. The Mammalian Auditory Pathways. A Tutorial Study Guide. The Myth of Executive Functioning. Sensorimotor Control of Grasping.

Brain Asymmetry and Neural Systems. Human Sleep and Cognition. Enhancing Performance for Action and Perception. Axons and Brain Architecture. Early Intervention in Psychotic Disorders. The Cerebellum and Cognition. The Neuroscience of Hallucinations. Cultural Influences on Brain Function. Sleep, Epilepsies, and Cognitive Impairment. Systems Neuroscience and Rehabilitation. Latent Inhibition and Its Neural Substrates.

The Auditory System in Sleep

Pain and the Conscious Brain. Current Issues in Developmental Psychology. The Brain and Conscious Unity.

Available on

Space, Time and Number in the Brain. Plasticity of the Auditory System. Psychoses of the Schizophrenic Spectrum in Twins. Integrative Functions in the Mammalian Auditory Pathway. Neural Models of Plasticity.