Audiological findings in individuals diagnosed with COVID-19

PurposeIt is thought that COVID-19 may cause hearing loss, but its effects on the hearing system are not clear. This study aimed to reveal the effects of COVID-19 on the auditory system by using various audiological measurement methods in individuals diagnosed with COVID-19.MethodsThirty individuals between the ages of 18–45, who were diagnosed with COVID-19 by PCR at least one month ago, and had no pre-COVID-19 hearing loss complaints, constituted the test group. Thirty individuals aged between 18 and 30 years and who had no history of hearing loss constituted the control group. Audiological evaluations of all participants were made with pure-tone audiometry, high-frequency audiometry, transient-evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and auditory brainstem response (ABR) measurements.ResultsA significant difference was found between the groups at all high frequencies between 4 and 14 kHz (p < 0.05). TEOAE amplitudes at 1500 Hz, 2000 Hz and 4000 Hz frequencies and DPOAE amplitudes at 4003 Hz and higher frequencies were significantly lower in the test group (p < 0.05). While there was a significant difference between the I, III and V absolute latencies between the groups (p < 0.05), there was no significant difference between the I-III, III-V and I-V interpeak latencies (p > 0.05) as a result of the ABR test.ConclusionThis study showed that COVID-19 can cause cochlear damage, especially at high frequencies. More studies are needed to determine the effects of COVID-19 on the auditory system.     

Obstructive Sleep Apnea–Hypopnea Ssyndrome and Hearing in Children

ObjectiveTo explore the relationship between hypoxemia and hearing in children with obstructive sleep apnea–hypopnea syndrome. Methods Auditory brainstem responses (ABRs) were recorded in 68 ears and distortion product otoacoustic emissions (DPOAEs) in 60 ears in children with OSAHS and type “A” tympanograms, and in 30 ears in normal children.ResultsABR latencies of waves I, III and V, and I–III, III–V and I–V intervals were not statistically different between OSAHS and normal children. Wave I latency was delayed in children with OSAHS compared to normal children3 (P < 0.05). DPOAE amplitudes in children with mild OSAHS were lower than normal children at 8 kHz (P < 0.05). DPOAEs were lower at 6 kHz and 8 kHz in children with moderate/severe OSAHS than normal children (P < 0.05).ConclusionCochlear function was affected when AHI was at or greater than 10/hour. ABR and DPOAE can be used to detect early changes in auditory function in children with OSAHS.     

obstructive sleep apnea-hypopnea syndrome and hearing in children

Objective To explore the relationship between hypoxemia and hearing in children with obstructive sleep apnea-hypopnea syndrome. Methods Auditory brainstem responses (ABRs) were recorded in 68 ears and distortion product otoacoustic emissions (DPOAEs) in 60 ears in children with OSAHS and type "A" tympanograms, and in 30 ears in normal children. Results ABR latencies of waves Ⅰ, Ⅲ and Ⅴ, and Ⅰ-Ⅲ, Ⅲ-Ⅴ and Ⅰ-Ⅴ intervals were not statistically different between OSAHS and normal children. Wave Ⅰlatency was delayed in children with OSAHS compared to normal children3 (P<0.05). DPOAE amplitudes in children with mild OSAHS were lower than normal children at 8 kHz (P<0.05). DPOAEs were lower at 6 kHz and 8 kHz in children with moderate/severe OSAHS than normal children (P<0.05). Conclusion Cochlear function was affected when AHI was at or greater than lO/hour. ABR and DPOAE can be used to detect early changes in auditory function in children with OSAHS.     

Electrophysiological examinations (ABR and DPOAE) of hearing organ in hemodialysed patients suffering from chronic renal failure

Deterioration of function of hearing organ is one of the most important clinical problem in uremic patients with chronic renal failure. The present study aimed to assess the function of hearing organ using the brainstem auditory evoked responses (ABR), impedance audiometry and distortion product otoacoustic emission cochlear function (DPOAE) in 31 haemodialysed patients with chronic renal failure (16 females and 15 males, mean age 43.0 years). The control group consisted of 15 healthy subjects. The latency of the waves I, III, V and I-V interpeak in evoked response audiometry were significantly longer in the patients with CRF (chronic renal failure) compared to the control group. Measurement of DPOAE showed decrease of DPOAE level in patients suffering from CRF. A influence of single hemodialysis and treatment of hemodialysis by 6 months on ABR latencies and DPOAE values were not observed.     

Interpreting auditory brainstem evoked responses and distortion product otoacoustic emissions in diabetic patients with normal hearing

ObjectiveHearing impairment is a reported late complication of diabetes mellitus (DM). Previous studies have suggested that microangiopathic complications may cause cochlear nerve function deterioration. We evaluated the auditory brainstem evoked responses (ABRs) and distortion product otoacoustic emission (DPOAE) results according to the presence of DM in subjects with normal hearing.MethodsA cross-sectional comparative study was conducted from January 2016 to January 2018. Auditory function tests including ABR and DPOAE were performed for outpatients complaining of unilateral tinnitus. All of analyses were conducted in ears without tinnitus on contralateral side of tinnitus ears. We included subjects showing hearing thresholds within 25 dB at 0.5, 1k, 2k, and 4k on pure tone audiometry. 45 ears in patients with type 2 diabetes mellitus and 85 ears in non-diabetic patients were finally enrolled in our study.ResultsDiabetic subjects showed significantly more prolonged absolute peak latencies (I, III, V) and inter-peak latencies (I–V, III–V) than non-diabetic subjects. However, there was no significant difference in the inter-peak latency (I–III) between these two groups. Diabetic subjects also showed significantly lower amplitudes at f2 frequencies of 1001, 1200, 1587, 4004, 5042, and 6348 Hz than non-diabetic subjects. Additionally, the prevalence of a DPOAE response, defined as 3 dB above the noise floor, was significantly lower in diabetic subjects than that in non-diabetic subjects.ConclusionDiabetic patients with normal hearing can still have abnormal ABR and DPOAE results due to diabetic neuroangiopathy. ABR and DPOAE assessments can help in detecting subclinical auditory dysfunction, which precedes the manifestation of hearing impairment in diabetic patients.     

Age-related changes in auditory function of rhesus monkeys (Macaca mulatta)

The purpose of this study was to investigate the changes in auditory function associated with aging in rhesus monkeys (Macaca mulatta) as a model for age-related changes in humans. One advantage of using monkeys from the Wisconsin Regional Primate Research Center was that lifestyle factors such as diet and excessive noise exposure were controlled. Twenty younger (mean: 10 years, 9 months, S.D.=+/-6 months) and 20 older (mean: 25 years, 11 months, S.D.=+/-11 months) monkeys were used in this study. Cochlear function in these monkeys was measured with distortion product otoacoustic emissions (DPOAEs); neural function was measured with auditory brainstem responses (ABRs) and middle latency responses (MLRs). Older monkeys had (1) significantly smaller DPOAEs, (2) significantly smaller ABR peak amplitudes, and (3) significantly longer ABR peak latencies compared to younger monkeys. Overall, these results suggest that older monkeys have decreased cochlear and neural function to the level of the brainstem as compared to younger monkeys. The decrease in DPOAE level and the increase in age accounted for approximately 70% of the increase in peak IV latency.     

畸变产物耳声发射在唇腭裂婴幼儿听力检查中的应用

目的探讨唇腭裂婴幼儿畸变产物耳声发射（distortion product otoacoustic emission,DPOAE）的特点,并将其与听性脑干反应（auditory brainstem response,ABR）阂值检查的结果加以对照,以探讨DPOAE在这类患儿听力检查中的应用价值。方法DPOAE检查63例（126耳）,年龄2个月-42个月,平均11.83个月。其中单纯腭裂组（以下简称腭裂组）23例（46耳）,腭裂并发唇裂及牙槽裂组（以下简称唇腭裂组）30例（60耳）,单纯唇裂组（以下简称唇裂组）10例（20耳）,每耳均检查8个频率,若2-5kHz4个频点有≥3个频点通过即为该耳通过。在上述患儿中,ABR阈值检查腭裂组17例（34耳）,唇腭裂组10例（20耳）,唇裂组6例（12耳）,以能重复引出V波的最小刺激强度为ABR阈值。结果DPOAE检查：腭裂组通过7耳,未通过39耳,通过率为15.22％;唇腭裂组通过6耳,未通过54耳,通过率为10.00％;唇裂组通过18耳,未通过2耳,通过率为90％。统计分析腭裂组与唇腭裂组无显著差异,而腭裂组与唇裂组,唇腭裂组与唇裂组均有显著差异。ABR阈值检查统计分析结果与DPOAE一致。将各组DPOAE通过率与ABR正常率进行比较,腭裂组及唇腭裂组中二者无差异（P〉0.05）,虽然唇裂组中二者有差异（P〈0.05）,但唇裂组ABR阈值反应的听力下降较轻（均≤50dB nHL）。从总体趋势上说,DPOAE与ABR阈值检查在检测的结果上是一致的。结论唇腭裂患儿DPOAE和ABR检测结果一致,与ABR相比,DPOAE具有快速、简便、易实施等特点,因此DPOAE可以作为唇腭裂婴幼儿听力检查的手段,但仍需进一步结合ABR及其他相关的听力检查,以明确听力损害的程度和类型。     

Cochlear nerve demyelination causes prolongation of wave I latency in ABR of the myelin deficient (md) rat

In this study, we examined the auditory brainstem responses (ABRs), distortion product of otoacoustic emissions (DPOAEs) and cochlear morphology of the myelin deficient (md) rat, which completely lacks central myelin but not peripheral myelin. ABRs showed a marked prolongation not only wave II-IV latencies but also wave I latency. Cochlear nerve fibers near the modiolus lost their myelin halfway into the internal auditory canal. DPOAEs also decreased at a lower frequency of the combined tone. Since nerve fibers ending at the apical turn of the cochlea passed through central portion of the cochlear nerve, wave I prolongation of ABRs and decrease of DPOAEs at a lower frequency might originate mainly from the demyelinated CNS part of the cochlear nerve and efferent olivocochlear bundle in the internal auditory canal.     

The role of auditory brainstem response in diagnosing auditory impairments of Dejerine-Sottas

Dejerine-Sottas disease is classified as hereditary motor sensory neuropathy (HMSN) type III and shows evidence of Friedreich's ataxia, significant reduction in nerve conduction velocity (NCV), hypomyelination and demyelination of the nerve fibers. In this study, a 10-years-old girl with Dejerine-Sottas disease is presented in which routine clinical signs (ataxia and reduced NCV) seem with significant impairments of auditory brainstem pathway. It is indicated that pure tone audiometry, standard tympanometry (tympanometry and acoustic reflex), and otoacoustic emissions (OAEs) showed normal results in both ears (normal peripheral auditory system). In contrast, auditory brainstem responses (ABRs) indicated abnormal findings in absolute latencies of I, III, and V and inter-peak latencies of I-III and I-V. These findings suggested auditory brainstem involvement especially in low and mid regions.     

Short-term pathophysiologic changes and histopathologic findings of the auditory pathway after closed head injury, using a rabbit model

Hearing impairment is a well-known consequence of closed head injury (CHI). The aim of this study was to elucidate the pathogenesis of CHI-induced hearing loss, using a rabbit model. Twelve New Zealand white rabbits were divided into two groups of 6. In the first group, CHI was induced mechanically, whereas the rabbits of the second group served as controls. Baseline distortion product otoacoustic emissions (DPOAEs), contralateral suppression (CS) of the DPOAEs and auditory brainstem response (ABR) were obtained. The same measurements were performed in the first group after CHI. Three hours later, the animals were sacrificed and their brain was excised and subjected to histopathologic examination. Mean I-III ABR latencies were increased and DPOAE amplitudes and CS values were reduced in the trauma group after CHI, at a statistically significant level. Histopathologic examination of the temporal lobe and brainstem showed multiple hemorrhagic and necrotic areas, with edema in the surrounding region. The vestibulocochlear nerve was severely damaged at its emerging site at the brainstem. In conclusion, both peripheral and central involvement of the auditory pathway was found after CHI. Otoacoustic emissions in conjunction with ABR may provide significant information on both peripheral and central auditory function.     

Auditory brainstem response in gas station attendants

Ototoxicity of organic solvents can affect the hearing system up to the cochlea level and the central structures of hearing.ObjectiveTo evaluate the neurophysiological integrity of the hearing system in subjects exposed to fuels using ABR.MethodProspective study. We evaluated attendants from three gas stations in Santa Maria/RS. The sample had 21 subjects, who were evaluated by auditory brainstem response.ResultsWe found an alteration in the absolute latencies of Waves I and III and in all the interpeak latencies, in the right ear. In the left ear there was a change in the absolute latencies of all Waves, and in all the interpeak intervals. A change in the interaural difference of Wave V was found in 19% of the individuals. In the group exposed for more than five years, there were subjects with a statistically significant changes: in the I-V interpeak of the right ear; in the absolute latency of Wave I and in the III-V interpeak of the left year.ConclusionExposure to fuels can cause alterations in the central hearing system.     

Otoacoustic emissions and brainstem evoked potentials in compound carriers of connexin 26 mutations

This study compares the effects of mutations in the gap junction protein connexin 26 (Cx26), on outer hair cells (OHCs), inner hair cells (IHCs) and auditory nerve/brainstem among carriers of these mutations. One hundred and twenty eight individuals, from a village with widespread consanguinity and congenital deafness, due to three Cx26 mutations, were selected among relatives of deaf persons, and divided into non-carriers, carriers of one mutation, homozygous to one mutation, or compound heterozygous carriers of two different mutations. Distortion product otoacoustic emissions (DPOAEs), auditory brainstem responses (ABRs) and audiometric evaluation were compared in these genetic groups. Hearing loss among homozygotes and compound heterozygotes was comparable and ranged from mild to profound. Most ABRs from these groups showed no responses or partial responses (peaks III, V) with prolonged latencies, but some individuals had all peaks at normal latencies. DPOAEs were absent, except sporadic responses. Carriers of one mutation had significantly smaller DPOAEs compared to non-carriers, although normal pure tone audiograms and ABRs were found in these groups. In conclusion, based on DPOAEs, Cx26 mutations may impact OHC function among carriers of one or two Cx26 mutations. IHC/nerve impairment among homozygotes and compound heterozygotes is variable. OHCs may be more susceptible to Cx26 mutations compared to IHCs and the auditory nerve and brainstem pathway activated by them.     

Screening of high-risk infants using distortion product otoacoustic emissions.

Otoacoustic emissions have been used as an objective and noninvasive test of cochlear function. Due to its ease of use, accuracy, and test-retest reliability, otoacoustic emissions testing is considered an excellent tool for evaluating difficult-to-test patients. This project involved screening infants at high risk of congenital hearing loss. These infants were selected from the Special Infant Clinic at Queen's University, Kingston, Ontario. The first part of this project was to establish a distortion product otoacoustic emissions (DPOAEs) "norm" as the reference for this group of patients. A prospective study was then conducted to compare DPOAE and auditory brainstem response (ABR) as screening tools for this group of patients. Auditory brainstem response has been the gold standard for evaluating the hearing status of these infants. We will also present our experience in testing over 50 patients at high risk of congenital hearing loss using DPOAEs.     

Brainstem Auditory Evoked Potentials in Patients With Ischemic Heart Disease

The authors of this study used the method of increased stimulus rate on brainstem auditory evoked potentials (BAEPs) in 30 patients with ischemic heart disease (IHD) and in an equal number of healthy age-matched control subjects. The BAEPs were recorded using 100- to 3000-Hz alternating polarity clicks at a rate of 22.6 per second. Measurements included the absolute latencies of waves I through V, the interpeak latencies I-III, III-V, and I-V, and the peak amplitudes of peaks I, III, and V. The measured absolute latencies and interpeak latencies were found to be significantly increased, and the peak amplitudes were found to be diminished. The audiometric tests revealed no significant hearing loss in IHD patients. This study is the first to demonstrate prolongation of BAEPs in IHD patients. BAEP recording may become an additional noninvasive tool for detecting IHD patients with impaired microcirculation.     

轻度感音神经性听力损失婴儿骨导ABR检测结果分析

目的探讨骨导听性脑干反应(ABR)检测在婴儿轻度感音神经性听力损失诊断中的价值。方法分别对30例(52耳)轻度感音神经性听力损失婴儿(患儿组)和30例(60耳)听力正常婴儿(正常组)行骨、气导ABR检测,并对两组结果进行分析比较。结果从40 dB nHL刺激强度开始,随着刺激强度下降,患儿组骨导ABR波V引出率逐渐下降;在40 dB nHL刺激强度下,患儿组骨导ABR波Ⅰ、Ⅲ、Ⅴ潜伏期较正常组稍延长,但差异无显著统计学意义(P>0.05)。患儿组骨、气导ABR反应阈均较正常组显著升高(P<0.05),但两组骨气导反应阈差值无明显差异(P>0.05)。结论骨导ABR检测对轻度感音神经性听力损失婴幼儿听力损失性质的鉴别诊断和评估具有重要的临床参考价值。     

Acute Effects of Alcohol on Auditory Thresholds and Distortion Product Otoacoustic Emissions in Humans

Objective—To investigate the acute effects of alcohol consumption on pure-tone thresholds (PTs) and distortion product otoacoustic emissions (DPOAEs) in humans. Material and Methods—Eight healthy adults were asked to drink alcohol to the clinical intoxication level. PTs and DPOAEs were determined serially before and after alcohol ingestion. Results—Alcohol had no effect on PTs. DPOAE amplitudes above 5500 Hz dropped 30 min and 1 h after alcohol ingestion, returning to the pre-test level 2 h after ingestion. Conclusion—In humans, acute alcohol consumption to the intoxication level may cause a temporary reduction in DPOAE amplitudes at high frequencies without affecting auditory thresholds.     

Investigation of auditory brainstem function in diabetic patients

We performed brainstem auditory evoked potential (BAEP) examinations in 15 patients with long-standing type 1 diabetes mellitus. We applied cardiovascular reflex tests for assessment of autonomic neuropathy. The aim of our investigation was to compare the BAEP results of this patient group with those of controls and to look for the possible correlation between alteration of the auditory brainstem function and cardiovascular autonomic neuropathy. Analysis of the latencies (waves I, II, III, and V) and the interpeak latencies (I-III and I-V) of BAEP revealed a significant difference between those of diabetics and those of healthy controls. The amplitudes of waves I, III, and V were definitely lower in comparison with amplitudes of healthy controls. We observed a positive correlation between the overall autonomic score and the latencies (waves III and V) and interpeak latencies (I-III, I-V). These data support the hypothesis that long-standing diabetes mellitus and diabetic neuropathy might be revealed as a cause of certain dysfunctions of the central auditory pathways.     

Auditory Brainstem Responses in Senile Presbycusis Patients over 90 years

Objective To analyze the characteristics of auditory brainstem response (ABR) in presbycusis patients el-der than 90 years. Methods Fourteen presbycusis patients elder than 90 years (presbycusis group, 91.1.4 ± 1.3 years, 26 ears) and 9 normal-hearing young adults (control group, 22.7 ± 1.2 years, 18 ears) participated in the study. Alternative click-evoked ABRs were recorded in both groups. The peak latency (PL) of peak I,Ⅲ, and V, and the inter-peak latency (IPI) of I-Ⅲ,Ⅲ-V, and I-V were compared between groups. Results In elder presbycusis patients, the occurrence rate of peak I andⅢwere both 76.9%, and that of peak V was 84.6%. In presbycusis group, the peak latencies of I, Ⅲ, V were significantly longer than that of control group (P<0.001). There was no significant difference between groups in the IPI of peak I-IⅢ (P=0.298, peakⅢ-V (P=0.254) and peak I-V (P=0.364). Conclusions Auditory brainstem responses in presbycusis pa-tients elder than 90 years showed worse wave differentiation.     

Auditory brainstem responses in dyslexia: comparison between acoustic click and verbal stimulus events

OBJECTIVES: This study examined the use of auditory brainstem response (ABR) by classic clicks and verbal stimuli in young dyslexic adults to identify latency abnormalities. METHODS: Subjects included 10 dyslexic adults and 10 age-, sex-, IQ-, education-, and hearing sensitivity-matched normal subjects. Both groups had normal auditory status. Measurements included the absolute latencies of waves I through V; the interpeak latencies I-III, III-V, and I-V elicited by acoustic click; and the negative peak latencies of A and B waves, as well as the interpeak latencies of A-B elicited by the verbal stimulus "ma," created on a digital speech synthesizer. RESULTS: The measured latencies and interpeak latencies in response to both clicks and verbal stimuli were found delayed in eight dyslexic subjects, although they did not reach the level of significant difference. However, two dyslexic subjects had significantly delayed peak and interpeak latencies elicited by verbal stimuli. CONCLUSIONS: There are dyslexic subjects who may have abnormalities in acoustic representation of a speech sound as low as the auditory brainstem, as elicited by the verbal stimulus "ma."     

Effects of PMCA2 mutation on DPOAE amplitudes and latencies in deafwaddler mice

The deafwaddler (dfw) mouse mutant is caused by a spontaneous mutation in the gene that encodes a plasma membrane Ca(2+) ATPase (type 2), PMCA2 (Street et al., 1998. Nat. Genet. 19, 390-394), which is expressed in cochlear and vestibular hair cells. Distortion product otoacoustic emission (DPOAE) amplitudes and latencies were examined in control mice, deafwaddler mutants, and controls treated with the drug furosemide. Furosemide causes a transient reduction of DPOAEs (Mills et al., 1993. J. Acoust. Soc. Am. 94, 2108-2122). We wanted to determine whether DPOAEs obtained in furosemide-treated mice were similar or different from results obtained in +/dfw mice. DPOAE amplitude and phase were measured as a function of f(2)/f(1) ratio. These data were converted into waveforms using inverse fast Fourier transform, and their average latency was used to estimate DPOAE group delay. Homozygous deafwaddlers did not produce DPOAEs. Heterozygous deafwaddlers (+/dfw) had increased DPOAE thresholds and reduced amplitudes at high frequencies, compared to controls. To the extent that DPOAEs depend on functional outer hair cells (OHCs), abnormal DPOAEs in +/dfw mice suggest that PMCA2 is important for OHC function at high frequencies. Similar to the effects of furosemide, the mutation reduced DPOAEs for low-level stimuli; in contrast to furosemide, the mutation altered DPOAEs elicited by high levels.