Use of the auditory brainstem response testing in the clinical evaluation of the patients with diabetes mellitus

Hyperglycemia-induced oxidative stress exacerbates mitochondrial apoptosis damage to cochlear stria vascularis pericytes via the ROS-mediated Bcl-2/CytC/AIF pathway

OBJECTIVES

Diabetes is closely linked to hearing loss, yet the exact mechanisms remain unclear. Cochlear stria vascularis and pericytes (PCs) are crucial for hearing. This study investigates whether high glucose induces apoptosis in the cochlear stria vascularis and pericytes via elevated ROS levels due to oxidative stress, impacting hearing loss.

METHODS

We established a type II diabetes model in C57BL/6J mice and used auditory brainstem response (ABR), Evans blue staining, HE staining, immunohistochemistry, and immunofluorescence to observe changes in hearing, blood-labyrinth barrier (BLB) permeability, stria vascularis morphology, and apoptosis protein expression. Primary cultured stria vascularis pericytes were subjected to high glucose, and apoptosis levels were assessed using flow cytometry, Annexin V-FITC, Hoechst 33342 staining, Western blot, Mitosox, and JC-1 probes.

RESULTS

Diabetic mice showed decreased hearing thresholds, reduced stria vascularis density, increased oxidative stress, cell apoptosis, and decreased antioxidant levels. High glucose exposure increased apoptosis and ROS content in pericytes, while mitochondrial membrane potential decreased, with AIF and cytochrome C (CytC) released from mitochondria to the cytoplasm. Adding oxidative scavengers reduced AIF and CytC release, decreasing pericyte apoptosis.

DISCUSSION

Hyperglycemia may induce mitochondrial apoptosis of cochlear stria vascularis pericytes through oxidative stress.

Exploring auditory temporal resolution and dichotic listening skills among individuals with type 2 diabetes mellitus

The study aimed to explore the auditory temporal resolution and dichotic listening skills in patients with type 2 diabetes mellitus (T2DM) and identify associated health-related factors. Using a cross-sectional design, 87 adults with T2DM and 48 non-diabetic controls, all with normal hearing, participated. The two central auditory processing (CAP) skills were assessed through the Gaps-In-Noise (GIN) and Dichotic-Digits Listening (DDL) tests. T2DM participants underwent blood tests to measure various health-related factors. In the GIN test, the shortest gap threshold (GapTh) obtained across both ears was significantly higher in the diabetic group (9.1 ± 2.4 ms) compared to the non-diabetic group (7.5 ± 1.5 ms), and the score of correctly identified gaps (GapSc) in the diabetic group (45±11 %) was significantly lower than GapSc in the non-diabetic group (52±9 %), p < 0.001. In the DDL test, the free-recall score (73.8 ± 18.5 %) across both ears and the right-ear advantage (-1.3 ± 20.6 %) in the diabetic group were significantly lower than the free-recall score (85.8 ± 11.9 %) and right-ear advantage (6.9 ± 11.9 %) in the non-diabetic group, p < 0.005. Furthermore, the duration of diabetes, eGFR level, retinopathy, carotid plaque, fasting blood glucose level, and HDL-C (good cholesterol) level were factors significantly associated with performances in the GIN and/or DDL tests for T2DM participants. In conclusion, individuals with T2DM are at risk of reduced auditory processing skills in temporal resolution and dichotic listening, impacting their speech understanding. Six health-related factors were identified as significantly associated with CAP skills in T2DM patients.

Subclinical Auditory Neural Deficits in Patients With Type 1 Diabetes Mellitus

Supplemental Digital Content is available in the text.

Objectives:

Diabetes mellitus (DM) is associated with a variety of sensory complications. Very little attention has been given to auditory neuropathic complications in DM. The aim of this study was to determine whether type 1 DM (T1DM) affects neural coding of the rapid temporal fluctuations of sounds, and how any deficits may impact on behavioral performance.

Design:

Participants were 30 young normal-hearing T1DM patients, and 30 age-, sex-, and audiogram-matched healthy controls. Measurements included electrophysiological measures of auditory nerve and brainstem function using the click-evoked auditory brainstem response, and of brainstem neural temporal coding using the sustained frequency-following response (FFR); behavioral tests of temporal coding (interaural phase difference discrimination and the frequency difference limen); tests of speech perception in noise; and self-report measures of auditory disability using the Speech, Spatial and Qualities of Hearing Scale.

Results:

There were no significant differences between T1DM patients and controls in the auditory brainstem response. However, the T1DM group showed significantly reduced FFRs to both temporal envelope and temporal fine structure. The T1DM group also showed significantly higher interaural phase difference and frequency difference limen thresholds, worse speech-in-noise performance, as well as lower overall Speech, Spatial and Qualities scores than the control group.

Conclusions:

These findings suggest that T1DM is associated with degraded neural temporal coding in the brainstem in the absence of an elevation in audiometric threshold, and that the FFR may provide an early indicator of neural damage in T1DM, before any abnormalities can be identified using standard clinical tests. However, the relation between the neural deficits and the behavioral deficits is uncertain.

Possíveis implicações audiológicas do diabetes melito: uma revisão de literatura

RESUMO: O objetivo deste trabalho é realizar uma revisão bibliográfica procurando analisar a relação entre diabetes melito, tipos I e II, e as possíveis alterações audiológicas. De acordo com os estudos analisados, pode-se concluir que existe relação entre alterações audiológicas e diabetes melito. Acredita-se ainda que há uma série de fatores que contribuem para tal associação, sendo necessários estudos mais criteriosos que estabeleçam o verdadeiro papel desses fatores.

Amelioration of Auditory Response by DA9801 in Diabetic Mouse

Diabetes mellitus (DM) is a metabolic disease that involves disorders such as diabetic retinopathy, diabetic neuropathy, and diabetic hearing loss. Recently, neurotrophin has become a treatment target that has shown to be an attractive alternative in recovering auditory function altered by DM. The aim of this study was to evaluate the effect of DA9801, a mixture of Dioscorea nipponica and Dioscorea japonica extracts, in the auditory function damage produced in a STZ-induced diabetic model and to provide evidence of the mechanisms involved in enhancing these protective effects. We found a potential application of DA9801 on hearing impairment in the STZ-induced diabetic model, demonstrated by reducing the deterioration produced by DM in ABR threshold in response to clicks and normalizing wave I–IV latencies and Pa latencies in AMLR. We also show evidence that these effects might be elicited by inducing NGF related through Nr3c1 and Akt. Therefore, this result suggests that the neuroprotective effects of DA9801 on the auditory damage produced by DM may be affected by NGF increase resulting from Nr3c1 via Akt transformation.

Hearing loss as a function of aging and diabetes mellitus: a cross sectional study

Background

Although hearing loss may be caused by various factors, it is also a natural phenomenon associated with the aging process. This study was designed to assess the contributions of diabetes mellitus (DM) and hypertension, both chronic diseases associated with aging, as well as aging itself, to hearing loss in health screening examinees.

Methods

This study included 37,773 individuals who underwent health screening examinations from 2009 to 2012. The relationships between hearing threshold and subject age, hearing threshold at each frequency based on age group, the degree of hearing loss and the presence or absence of hypertension and DM were evaluated.

Results

The prevalence of hearing loss increased with age, being 1.6%, 1.8%, 4.6%, 14.0%, 30.8%, and 49.2% in subjects in their twenties, thirties, forties, fifties, sixties, and seventies, respectively (p<0.05). Hearing value per frequency showed aging-based changes, in the order of 6000, 4000, 2000, 1000 and 500 Hz, indicating greater hearing losses at high frequencies. The degree of hearing loss ranged from mild to severe. Aging and DM were correlated with the prevalence of hearing loss (p<0.05). There was no statistically significant association between hearing loss and hypertension after adjusting for age and DM.

Conclusions

The prevalence of hearing loss increases with age and the presence of DM. Hearing loss was greatest at high frequencies. In all age groups, mild hearing loss was the most common form of hearing loss.

Cochleopathy in Egyptian adolescents with Type 1 diabetes mellitus

BACKGROUND

Diabetic neuropathy is recognized as the most common clinical picture of nervous system disorders caused by diabetes mellitus (DM). Although peripheral and autonomic nervous system involvements are frequently encountered, data about the incidence of central diabetic neuropathies is limited.

OBJECTIVE

Our study aimed to detect early asymptomatic auditory impairment whether at the level of outer hair cells (OHCs), inner hair cells (IHCs) and or olivo-cochlear bundle and the relationship between these abnormalities and other variables such as diabetes duration, degree of the metabolic control, or presence of microvascular complications.

SUBJECTS AND METHODS

Seventy five adolescents with Type 1 DM and thirty three healthy controls participated in the study. Duration of DM, glycated hemoglobin (HbA1c) levels, microvascular complications were analyzed. All underwent basic audiological assessment to ensure normal hearing and normal middle ear function. Other tests comprised: transiently evoked otoacoustic emissions (TEOAEs) testing OHCs, TEOAEs with contralateral suppression (testing the integrity of olivo-cochlear bundle) and threshold equalizing noise (TEN) testing IHCs as evidenced by dead regions within the cochlea.

RESULTS

Early asymptomatic OHCs involvement as reflected by partial pass in 33.3% of cases with diminished suppression as compared to 9.1% control group. Eleven patients (7.33%) showed positive TEN Test reflecting resistance of IHCs to hyperglycemic injury. Diabetic patients had significantly higher amplitude on TEOAEs with noise suppression when compared to controls (P=0.002). The mean difference in amplitude of TEOAEs before and after suppression was significantly higher in diabetics with microvascular complications when compared to diabetic children without complications at all frequencies (P<0.001 for all). Duration of diabetes and microvascular complications (nephropathy, peripheral and autonomic neuropathy) were not correlated with the lack of suppression except for retinopathy (P=0.02). In contrast, poor metabolic control was associated with poor suppression (r=-0.443, P=0.001).

CONCLUSIONS

Cochleopathy can be detected in a relatively high proportion of subjects with Type 1 diabetes in spite of a normal audiometric hearing threshold. It should be considered as early manifestation of diabetic neuropathy which is related to the degree of metabolic control and retinopathy independent of other microvascular complications.

Association between hepatitis B and hearing status

OBJECTIVE

Viral diseases are one of the common causes of hearing loss. The inner ear may be involved directly or by secondary reaction (e.g., polyarthritis nodosa). This study was performed to investigate the relation between positive HBS-Ag (hepatitis B disease) and hearing loss.

METHODS

This case-study research was done on 95 hepatitis-B patients as the case group and 97 normal cases as the control group. They were selected sequentially and audiologic tests were performed on the participants. The hearing thresholds of the two groups were compared using the t-test.

RESULTS

According to audiometry results, pure tone average (mean thresholds of 500, 1000 and 2000 Hz) were 22.1 dB for the left ear and 23.95 dB for the right ear in hepatitis-B group and 8.4 dB for the left ear and 8.95 dB for the right ear in the control group (HBS-Ag negative). The difference between two groups was statistically significant with p-value less than 0.05.

CONCLUSION

The results show that hepatitis-B patients are more prone to hearing loss and that hepatitis B disease can cause hearing loss. This study suggests that hepatitis B prophylaxis is important in decreasing hepatitis-B involvement and therefore, hearing loss.

Diabetes-related changes in auditory brainstem responses

OBJECTIVES/HYPOTHESIS

Determine effects on auditory brainstem response (ABR) of diabetes mellitus (DM) severity.

STUDY DESIGN

A cross-sectional study investigating DM severity and ABR in military Veteran subjects with (166) and without (138) DM and with no more than moderate hearing loss.

METHODS

Subjects were classified by three age tertiles (<50, 50-56, and 57+). DM severity was classified as insulin-dependent (IDDM), non-insulin-dependent (NIDDM), or no DM. Other DM measures included serum glucose, HbA1c, and several DM-related complications. ABR measures included wave I, III, and V latencies; I-III, III-V, and I-V latency intervals; and wave V amplitude; for each ear at three repetition rates (11, 51, and 71 clicks/second), and both polarities. Outcomes were stratified by age tertile and adjusted for pure tone threshold at 3 kHz. Repeated measures multivariate analysis of covariance modeled the ABR response at each repetition rate for DM severity (main effect) and hearing at 3 kHz (covariate). Modeled contrasts between ABR variables in subjects with and without DM were examined.

RESULTS

Significant differences existed between no DM and IDDM groups in the younger tertile only. Adjusting for threshold at 3 kHz had minimal effect. Self-reported noise exposure was not related to ABR differences, but HbA1c and poor circulation were.

CONCLUSIONS

IDDM is associated with an increased wave V latency, wave I-V interval, and reduced wave V amplitude among Veterans under 50 years. Results were related to several DM complications.

Otoacoustic emissions and effects of contralateral white noise stimulation on transient evoked otoacoustic emissions in diabetic children

OBJECTIVE

In this study, our aim was to determine presence of dysfunction in the efferent auditory system of children with type-I diabetes mellitus (DM) presenting no evidence of symptomatic neuropathy.

METHODS

Thirty children with type-I DM (DM group) and 31 age matched healthy children (control group) with normal hearing and middle ear function were entered to the study. Distortion product otoacoustic emissions (DPOAE), transiently evoked otoacoustic emissions (TEOAE), and spontaneous otoacoustic emissions (SOAE) measurements were performed. Then, the TEOAE recording was repeated while a continuous broadband white noise (bandwidth: 50-8000 Hz) presented at 40 dB SL was delivered to the contralateral ear for efferent auditory system suppression.

RESULTS

We found that contralateral stimulation (CS) with white noise resulted in significantly more pronounced suppression of the TEOAE response amplitude in healthy controls compared to DM group at 2000 and 4000 Hz frequencies. Further, a relatively higher percentage of the controls had suppression in at least three frequencies compared to DM group. SOAE prevalence was found to be higher in the DM group.

CONCLUSIONS

Our findings suggest presence of a dysfunction in medial olivocochlear efferent system in diabetic children. This may be regarded as an early central manifestation of diabetic neuropathy.

Pentoxifylline response in alloxan-induced diabetic rats

CONCLUSION

This study in rats shows that pentoxifylline may reverse detrimental effects of diabetes mellitus (DM) on the auditory system.

OBJECTIVE

To investigate whether delayed auditory brainstem responses (ABRs) induced by DM improve following pentoxifylline treatment in rats.

MATERIALS AND METHODS

Baseline ABRs were recorded in 25 ears of 13 normal-hearing rats. DM was induced by a single injection of alloxan (75 mg/kg of body weight) in all rats. Following a 1-month diabetic period, ABRs were recorded in six diabetic rats. Then, pentoxifylline treatment was administered for 6 weeks (20 mg/kg in drinking water), and final ABR testing was performed. Absolute latencies of waves I, III and V, and inter-peak latency differences (IPL) of I-V were measured in each stage of the experiment. These parameters were compared to each other in a pair-wise manner.

RESULTS

All wave latencies and IPL I-V were prolonged following induction of DM. Delay in waves III and V, and IPL I-V was significant (p<0.05). Pentoxifylline improved all of the wave latencies and IPL I-V, but significant improvement was observed in waves III and V (p<0.05). There was no significant difference between baseline measurements and measurements following pentoxifylline treatment.

Brainstem auditory evoked potentials and middle latency auditory evoked potentials in patients with impaired glucose tolerance

AIMS

The aim was to investigate the effects of impaired glucose tolerance (IGT) on the central nervous system via brainstem auditory evoked potentials (BAEPs) and middle latency auditory evoked potentials (MLAEPs), and on the peripheral nervous system via nerve conduction studies (NCS).

METHODS

Thirty patients with IGT and 20 control subjects underwent NCS, BAEPs and MLAEPs.

RESULTS

Tibial distal motor latencies were significantly prolonged in the IGT group; no differences in other parameters, including BAEPs and MLAEPs, were observed between the IGT and control subjects.

CONCLUSION

Brainstem involvement may not be seen in IGT patients as in DM. The was no obvious electrophysiological finding indicating peripheral nervous system disfunction in our patients.

Auditory Impairment in Patients with Type 2 Diabetes Mellitus

BACKGROUND

We assessed the auditory function of 94 patients with type 2 diabetes mellitus and 94 age- and sex-matched healthy subjects.

METHODS

To study the influence of the clinical characteristics of the disease on the auditory function, after a clinical interview with ophthalmological assessment, subjects were evaluated using pure-tone audiometry, speech audiometry, auditory brainstem responses, the Michigan Diabetic Neuropathy Score and albuminuria. The mean age when diabetes was diagnosed was 42.8 +/- 6.5 years (mean +/- SD) and the time elapsed since diabetes diagnosis was 7.2 +/- 5.4 years.

RESULTS

Forty-eight patients (62%) had HbA1c >8%; diabetic retinopathy was evident in 14 patients (14%) and microalbuminuria was identified in 12 patients. Compared to healthy subjects, diabetic patients showed an increase of the perception threshold at 8000 Hz (p <0.01), higher hearing levels to discriminate at least 90% of 10 monosyllables (p <0.01), and longer latencies of wave V, interwave I-V and interwave III-V (p <0.01). Significant correlation was found between the hearing threshold at 8 KHz and patient age, and the former and the time elapsed since the diabetes was diagnosed (p <0.001).

CONCLUSIONS

Patients with type 2 diabetes mellitus can have subclinical hearing loss and impaired auditory brainstem response, independent of peripheral neuropathy, retinopathy or nephropathy.

Hearing status in brucellosis

BACKGROUND

Although brucellosis can lead to multisystem complications, involvement of the ear in brucellosis is rarely reported in the literature. The purpose of this study was to assess the hearing status of patients with brucellosis.

STUDY DESIGN

Thirty-two patients with brucellosis were included in the study. Pure tone and speech audiometry and tympanometry were performed in the patients.

RESULTS

The mean pure tone averages of the patients were within normal limits and were similar in both ears (P > 0.05). The pure tone averages of the patients with or without anti-Brucella treatment were not significantly different (P > 0.05) and were within the normal limits. When the hearing levels of these patients were compared at the frequencies of 250, 500, 1000, 2000, 4000, and 8000 Hz, there was no significant difference as well (P > 0.05).

CONCLUSIONS

Peripheral brucellosis does not appear to be associated with hearing loss.

Neurotologic manifestations of the fibromyalgia syndrome

The purpose was to assess otologic symptoms, and audiologic and vestibular findings in fibromyalgia (FM) syndrome. Twenty-four female patients with FM syndrome (FMS) were included in the study. The assessments were based on history, physical examination, audiometry, bithermal caloric testing and auditory brainstem response (ABR) testing. Dizziness was the most common complaint of the patients, and was followed by tinnitus, hearing loss and vertigo. Almost 50% of the patients had some sort of otologic symptoms.Dix-Halpike maneuver proved positional rotary vertigo in 5 (20.8%) patients. The audiometry results of 23 patients were normal. None of the patients had abnormal bithermal caloric testing. Although there were a variety of ABR abnormalities, the ABR results of the patients with and without cochleovestibular symptoms were not significantly different (p<0.05). In conclusion, FM patients can complain otologic symptoms even though they do not have any clinically or audiologically detectable ear disease. A neural disintegration or some other events related to neural mediators may be the mechanisms involved in the pathogenesis of otoneurologic as well as systemic manifestations of the disease that possibly leads to abnormal perception of the stimuli coming from internal or external environment.