Type-2 diabetes mellitus and auditory brainstem response

Audiological profile of patients with type 2 diabetes mellitus

BACKGROUND

 South Africa shows a high prevalence of type 2 diabetes with reported association with auditory dysfunction.

OBJECTIVES

 To describe the audiological profile of adults with this metabolic condition.

METHOD

 Employing a descriptive research design, 35 individuals with type 2 diabetes, selected through purposive sampling, underwent a basic audiological assessment in addition to extended high-frequency (EHF) audiometry, distortion product otoacoustic emissions (DPOAE) testing and neurological auditory brainstem response (ABR) test.

RESULTS

 This study revealed a 31.4% prevalence of hearing loss with 81.8% being sensorineural in nature. Poor hearing thresholds were observed at 16 kHz (n = 19; 54.3%), 18 kHz (n = 24; 68.6%) and 20 kHz (n = 30; 85.7%) in the right ear and at 16 kHz (n = 20; 57.1%), 18 kHz (n = 24; 68.6%) and 20 kHz (n = 30; 85.7%) in the left ear. Absent DPOAEs were observed at 6 kHz (n = 20; 51.7%) and 8 kHz (n = 24; 68.6%) in the right ear and at 6 kHz (n = 17; 48.6%) and 8 kHz (n = 29; 82.9%) in the left ear, possibly indicating that type 2 diabetes specifically targets higher frequency hearing. The ABR results revealed a delayed absolute latency of wave III bilaterally (right ear -69%; left ear - 51%), suggesting an impact of this metabolic disease on retro-cochlear pathways.

CONCLUSION

 Hearing loss should be recognised as a comorbidity accompanying type 2 diabetes, which indicates the need for routine comprehensive audiological assessments to facilitate early detection and intervention.Contribution: The present findings have implications for audiology clinical protocols; diabetes related health policies and patient education.

Assessing the Brainstem Auditory Evoked Potentials in Subjects with Family History of Hypertension

Background

Hypertension (HTN) has a genetic predisposition and it also impairs microcirculation, thereby, affecting the well vascularized structures like the brainstem and causing changes in Brainstem Auditory Evoked Potentials (BAEPs).

Purpose

To find out the usefulness of BAEPs as a screening tool in apparently healthy individuals with a family history of HTN.

Methods

One hundred and ten volunteers, aged 17 to 23 years, were enrolled in the study as participants with proper consent. After excluding the subjects with existing diseases or co-morbidities (e.g. diabetes, HTN, schizophrenia, neuropathy, etc.), those on ototoxic or neurotoxic drugs, a preliminary physical examination was performed, following which BAEPs were recorded with a proper device. Statistical analysis is done with SPSS 2016 software using the chi-square test.

Results

A consistent distortion in the inter-peak latency of III-V waves is noted when a family history of HTN is present in either parent or maternal grandparents. Other statistically significant findings are present in V/I% (HTN in mother), wave I (HTN in paternal grandfather), wave III (HTN in maternal grandfather), and inter-peak latency I-V (HTN in maternal grandmother).

Conclusion

BAEP may be used as a screening tool in individuals with a family history of HTN with supportive evidence from further studies in the near future.

The distribution pattern of M2 and Adrenergicα2 receptors on inferior colliculi in male newborns of diabetic rats

AIMS

Despite the high prevalence of diabetes in the world, its possible effects throughut pregnancy on neonatal auditory nervous system development are still unknown. In the present research, maternal diabetes' impact on the M2 and Adrenergic_α2 receptors expression in the inferior colliculus (IC) of male newborn rats was investigated. Main methods Female rats were grouped into three: sham, insulin-treated diabetic, and diabetic. Diabetes was induced through streptozotocin (STZ) injection as one dose intraperitoneally (65 mg/kg). After mating and delivery, male rats were euthanized on P0, P7, and P14. Immunohistochemistry (IHC) was used to study the distribution pattern of receptors. Key findings The present study indicated that the expression of M2 receptors in the diabetic group was significantly increased in pairwise comparisons in the sham and diabetic treated with insulin groups (P<0.001, each). The highest M2 expression was for the diabetic group on P14 and the lowest one was for the sham group on P0. The Adrenergic_α2a receptors expression in the diabetic group was significantly reduced in pairwise comparisons in the sham and diabetic treated with insulin groups (P <0.001, each). The highest Adrenergic_α2a expression was for the sham group on P14 and the lowest one was for the diabetic group on P0. There was no significant difference between the sham and insulin groups regarding all receptors expression.

SIGNIFICANCE

This study demonstrated a time-dependent significant decrease in Adrenergic_α2a but a time-dependent significant increase in M2 receptors expression.

Brainstem auditory evoked potential in cognitive impairment in patients with type 2 diabetes mellitus

PURPOSE

Type 2 diabetes mellitus (T2DM) can cause mild cognitive impairment (MCI) which threatens the health of patients. So the diagnosis of MCI is particularly important. It is reported that brainstem auditory evoked potential (BAEP) is a sensitive tool to detect the brainstem function in patients with T2DM. This study aimed to investigate the relationship between BAEP and MCI in patients with T2DM.

METHODS

A total of 244 T2DM patients with normal hearing, including 117 normal cognition patients and 127 MCI patients, were recruited in this cross-sectional study. Each subject underwent the BAEP examination. The diagnosis of MCI was based on the diagnostic guideline developed by the National Institute on Aging-Alzheimer's Association workgroups. The Montreal Cognitive Assessment (MoCA) was used to assess the cognitive function of the subjects.

RESULTS

Compared with the normal cognition group, the patients in the MCI group had longer latencies of waves III and V and interpeak latencies (IPL) I-V in both ears (P < 0.05). The significant negative correlations were found between the latencies of waves III, V, IPL I-V, and MoCA score in both ears (P < 0.05). Logistic regression showed that the prolongations of latunits of waves III and V and IPL I-V in both ears were still associated with MCI after adjustment for mixed factors (P < 0.05).

CONCLUSION

These results indicate abnormal auditory pathway in brainstem of T2DM patients with MCI. BAEP may contribute to the clinical diagnosis of MCI in patients with T2DM.

To Study Brain Stem Auditory Evoked Potential in Patients with Type 2 Diabetes Mellitus- A Cross- Sectional Comparative Study

INTRODUCTION

Neuropathy is one of the commonest complications of Diabetes Mellitus (DM). Apart from having peripheral and autonomic neuropathy patients with type 2 DM may also suffer from sensory neural hearing loss, which is more severe at higher frequencies. However, few studies have done detailed evaluation of sensory pathway in these patients. In this study brain stem auditory evoked potential is used to detect the acoustic and central neuropathy in a group of patients with type 2 DM with controlled and uncontrolled blood sugar.

AIM

To study brain stem auditory evoked potential in patients of type 2 DM with controlled and uncontrolled blood sugar and to correlate the various parameters e.g., age (years), weight (kilograms), height (meters), BMI (kg/m²), HbA1c (%) in patients with type 2 DM with controlled and uncontrolled blood sugar.

MATERIALS AND METHODS

Cross-sectional comparative study conducted from January 2014 to January 2015. Total 60 patients with type 2 DM of either sex, between age groups of 35-50 years were enrolled from the Diabetic Clinic of Medicine department, of a tertiary care hospital. Based on the value of HbA1c, patients were divided in two groups with controlled and uncontrolled blood sugar and with each group comprising of 30 patients. BERA (Brainstem Evoked Response Audiometry) was done in both the groups on RMS ALERON 201/401. Recordings were taken at 70dB, 80dB and 90dB at 2KHz frequency. Absolute latency of wave I, III, V and interpeak latencies I-III, III-V and I-V were recorded.

RESULTS

Mean±SD of the absolute latency of BERA waves I, III, V and interpeak latencies I-III, III-V and I-V at 2 KHz and at varying intensity of 70dB, 80dB and 90dB in uncontrolled group of DM were delayed and were significant as compared to controlled group of DM.

CONCLUSION

If BERA is done in diabetic patients, central neuropathy can be detected earlier in uncontrolled groups of diabetic patients.

Is there a direct correlation between the duration and the treatment of type 2 diabetes mellitus and hearing loss?

AIM

The aim of the study was to determine the impact of the duration of diabetes and the control of glycemia on the auditory function of patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

This prospective study included 80 patients with T2DM (divided depending on when T2DM was diagnosed, and also according to the control of glycemia), and 50 healthy subjects.

RESULTS

The hearing threshold in T2DM patients was statistically significantly higher for 1,000 Hz, 2,000 Hz, 4,000 Hz and 8,000 Hz. Absolute latencies of brainstem auditory evoked potentials (BAEP) revealed significant differences between average absolute latencies for waves I, III and V, as well as inter-wave latencies I‒V and I‒III (p <0.001). A statistically significant difference was noted in the presence of transitory otoacoustic emissions (TEOAE) (p <0.001). In T2DM patients with poor glycemic control, where the glycated hemoglobin (HbA1c) is above 7%, the hearing threshold levels were statistically significantly higher in both ears at 8,000 Hz and at 2,000 Hz in the right ear, and the absolute latency of wave V was prolonged in the right ear. There was no evidence that the duration of diabetes significantly affected the auditory threshold, absolute and inter-wave BAEP latencies.

CONCLUSION

The patients with T2DM displayed an increased hearing threshold, qualitative changes in BAEP and the absence of TEOAE. The duration of poorly-controlled glycemia had a greater effect on the patients' auditory function than the duration of T2DM. Hippokratia 2016, 20(1): 32-37.

Auditory Impairment in Young Type 1 Diabetics

BACKGROUND AND AIMS

More attention has recently been focused on auditory impairment of young type 1 diabetics. This study aimed to evaluate auditory function of young type 1 diabetics and the correlation between clinical indexes and hearing impairment.

METHODS

We evaluated the auditory function of 50 type 1 diabetics and 50 healthy subjects. Clinical indexes were measured along with analyzing their relation of auditory function.

RESULTS

Type 1 diabetic patients demonstrated a deficit with elevated thresholds at right ear and left ear when compared to healthy controls (p <0.01). The elevated auditory threshold was significantly related with HDL-cholesterol, diabetes duration, and systemic blood pressure (p <0.05). Moreover, latencies of right ear (wave III, V and interwave I-V) and left ear (wave III, V and interwave I-III, I-V) in diabetic group significantly increased compared to those in control subjects (p <0.01). Auditory brainstem response was significantly related with GHbA1C and microalbuminuria (p <0.01). Furthermore, distortion product evoked otoacoustic emissions (DPOAE) of diabetes group were statistically significant in right ears at 4.0, 6.0 kHz and in left ears at 4.0, 6.0, 8.0 kHz (p <0.01) compared with those of controls. Diabetic patients demonstrated lower amplitude responses of the right ear than the left ear at 8.0 kHz. Only triglyceride was positively correlated to the hearing impairment defined by DPOAE (p <0.01). There was no significance of transient evoked otoacoustic emissions (TEOAE) between groups. TEOAE was associated with age and GHbA1C (p <0.01).

CONCLUSIONS

Type 1 diabetics exerted higher auditory threshold, slower auditory conduction time and cochlear impairment. HDL-cholesterol, diabetes duration, systemic blood pressure, microalbuminuria, GHbA1C, triglyceride, and age may affect the auditory function of type 1 diabetics.

Long-term noise exposure and the risk for type 2 diabetes: a meta-analysis

Diabetes mellitus is one of the leading causes for disability and mortality in modern societies. Apart from personal factors its incidence might be influenced by environmental risks such as air pollution and noise. This paper reports a systematic review and meta-analysis on the risk for type 2 diabetes due to long-term noise exposure. Electronic searches in MEDLINE, EMBASE and the Internet yielded 9 relevant studies (5 for residential and 4 for occupational exposure). They were checked against a predefined list of safeguards against bias producing individual quality scores, which were then fed to MetaXL to conduct a quality effects meta-analysis. People exposed at their homes to roughly L(den) > 60 dB had 22% higher risk (95% confidence interval [CI]: 1.09-1.37) for type 2 diabetes in comparison to those exposed to L(den) < 64 dB; when studies reporting contentious exposure categories were excluded, there was still 19% risk (95% CI: 1.05-1.35) for L(den) = 60-70 dB versus L(den) < 60 dB. In occupational environment there was not significant risk (relative risk [RR] = 0.91, 95% CI: 0.78-1.06) for < 85 dB versus >85 dB. There was no heterogeneity in the two groups (I² = 0.00). The results should be interpreted with caution due to methodological discrepancies across the studies; however, they are indicative of the close links that noise pollution might have not only to cardiovascular diseases but to endocrine dysfunction as well.

microRNA-18a is a genetic marker for the early diagnosis of cerebral injury induced by type 2 diabetes

The present study aimed to investigate the value of microRNA (miRNA)-18a for the early diagnosis of cerebral injury in patients with type 2 diabetes. Blood samples were collected from patients with type 2 diabetes, admitted to hospital between January and December 2013. The patients were randomly divided into three groups, which included one control and two experimental groups of severely and mildly diabetic patients (33 individuals per group). The levels of biochemical indicators in the serum, including S100 protein, neuron-specific enolase, myelin basic protein and endothelin-1, were determined. The mRNA and protein expression levels of hypoxia-inducible factor (HIF)-1α in the serum were measured by quantitative polymerase chain reaction (qPCR) and western blot analysis, respectively. In addition, the serum expression levels of miRNA-18a were determined by qPCR. The concentrations of the biochemical indicators in the severe diabetes group were significantly higher compared with those from the other two groups. Furthermore, the mRNA and protein expression levels of HIF-1α in the severe diabetes group were significantly upregulated compared with the other groups. However, the levels of miRNA-18a in the severe diabetes group were significantly downregulated compared with the other groups. The present study demonstrated that the elevation of biochemical indicators in the serum and the upregulation of HIF-1α mRNA and protein expression are associated with the downregulation of miRNA-18a. Therefore, miRNA-18a may be a potential genetic marker for the early diagnosis of cerebral injury induced by type 2 diabetes.