VEMP responses are not affected in non-insulin-dependent diabetes mellitus patients with or without polyneuropathy

When, where, and why should we look for vestibular dysfunction in people with diabetes mellitus?

The biochemistry of diabetes mellitus results in multi-system tissue compromise that reduces functional mobility and interferes with disease management. Sensory system compromise, such as peripheral neuropathy and retinopathy, are specific examples of tissue compromise detrimental to functional mobility. There is lack of clarity regarding if, when, and where parallel changes in the peripheral vestibular system, an additional essential sensory system for functional mobility, occur as a result of diabetes. Given the systemic nature of diabetes and the plasticity of the vestibular system, there is even less clarity regarding if potential vestibular system changes impact functional mobility in a meaningful fashion. This commentary will provide insight as to when we should employ diagnostic vestibular function tests in people with diabetes, where in the periphery we should look, and why testing may or may not matter. The commentary concludes with recommendations for future research and clinical care.

The impact of vestibular dysfunction on falls and postural instability in individuals with type 2 diabetes with and without diabetic polyneuropathy

Aim

This study aimed to determine the association between vestibular dysfunction, falls, and postural instability in individuals with type 2 diabetes (T2D) compared to healthy control individuals and to examine the impact of diabetic polyneuropathy (DPN).

Methods

This cross-sectional study included individuals with T2D with DPN (n = 43), without DPN (n = 32), and healthy controls (n = 32). Cervical and ocular vestibular evoked myogenic potentials (VEMP) were recorded, and latencies and amplitudes were determined. DPN was diagnosed based on nerve conduction studies and clinical scores. Postural instability was examined using a static posturographic balance system and calculated as an instability index (ST). Falls were recorded retrospectively during the past year. Group comparisons were conducted by using univariate and bivariate statistics.

Results

Individuals with T2D experienced more falls than healthy controls (T2D with DPN n = 12[38%], T2D without DPN n = 15[35%], controls n = 5[16%], p = 0.04). Individuals with T2D had decreased postural stability, T2D with DPN, ST (median of 52[iqi = 33; 77]), T2D without DPN, ST (median of 31[iqi = 24; 39]), controls ST (median of 26[iqi = 19; 33], p = 0.01), when comparing all three groups. Individuals with T2D had a greater number of no-responses in oVEMP compared to controls (T2D with DPN, n = 15[46.9%] T2D without DPN n = 25[58.1%], controls n = 9[28.1%], p = 0.04). No difference was found in cVEMP and oVEMP amplitudes in any of the groups. Irrespectively of DPN, fallers with T2D had decreased oVEMP and cVEMP latencies on the right ears, when comparing to non-fallers, respectively, n10 (fallers [median of 16, iqi=15;19 ms.] vs. non-fallers [median of 25 iqi=16;35 ms]); p13 (fallers [median of 16, iqi=15;17 ms.] vs. non-fallers [median of 15, iqi=8;16 ms.], p < 0.05).

Conclusion

Falls and postural instability were more frequent in individuals with T2D compared to healthy controls. Fallers with T2D had vestibular end-organ impairments based on the oVEMP and cVEMP latencies on the right but not the left ears, irrespective of DPN. Individuals with T2D had more frequent no-response of the oVEMP, indicating impaired vestibular nerve function.

Cervical Vestibular-Evoked Myogenic Potentials in Individuals with Diabetes Mellitus: A Systematic Review and Meta-Analysis

Vestibular evoked myogenic potentials (VEMPs) in individuals with diabetes mellitus (DM) provide evidence as how diabetes can bring about changes in the peripheral nervous system. Cervical VEMP (cVEMP) evaluates the function and integrity of the sacullo- collic pathway and ocular VEMP (oVEMP) evaluates the utriculo-collic pathway. cVEMP is an ipsilateral inhibitory response of the sternocleidomastoid muscle. cVEMP is recorded at higher intensity above 80-85 dBnHL with biphasic waveforms having initial peak positivity P13 followed by a negativity N23. We performed a systematic review following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines to evaluate cVEMP in diabetes mellitus. The search was conducted in the databases: PubMed, Cumulative Index of Nursing and Allied Health Literature, Scopus, and Cochrane library using the keywords "diabetes mellitus" and "vestibular evoked myogenic potential" or "cVEMP." A two-phase selection process was used for the final inclusion of studies, and the methodological quality of these studies was assessed using the Newcastle Ottawa scale (NCOS). Meta-analysis was performed using a random-effects model. For comparisons between DM and healthy controls, a significant difference was observed for cVEMP amplitude (P = 0.01). Our meta-analysis's results suggest peripheral vestibular dysfunction can be observed in DM. It appears that cVEMPs may be useful in the early detection of neuropathy in DM.

Vestibular function for children with insulin dependent diabetes using cervical vestibular evoked myogenic potentials testing

BACKGROUND

Healthy vestibular system adjusts balance during static and dynamic conditions. This is important for normal development (standing up and walking). Vestipulopathies (central and peripheral) are common complications of diabetes in adult population. Related studies are scare in children with type 1 diabetes (T1D).

AIM

To assess saccular function of otolith organ in children with T1D and predictors for its dysfunction.

METHODS

Cervical vestibular evoked myogenic potential (cVEMP) was used for objective evaluation.

RESULTS

The study included 40 patients (boys = 15; girls = 25). Patients had mean age of 13.63 ± 1.50 years, duration of diabetes of 5.62 ± 2.80 years, frequent attacks of diabetic ketoacidosis (55%) and hypoglycemia (30%), hyperlipidemia (20%), hypertension (12.5%) and peripheral neuropathy (40%). Dizziness was found in 10%. Compared to healthy children (n = 25), patients had prolonged cVEMP P1 and N1 latencies and reduced P1-N1 amplitude. Bilateral cVEMP abnormalities were found in 60% (vs 25% for unilateral abnormalities). Higher frequencies and severe vestibulopathies were found with chronic diabetes of > 5 years, hemoglobin A1c values > 7%, frequent diabetic ketoacidosis and hypoglycemic attacks and presence of dizziness. Regression analyses showed that predictors for prolonged P1 latencies and reduced P1-N1 amplitudes were only chronic diabetes (> 5 years) {odds ratio (OR) = 2.80 [95% confidence interval (CI): 1.80–5.33], P = 0.01; OR = 3.42 (95%CI: 2.82–6.81)} and its severity (hemoglobin A1c > 7%) [OR = 3.05 (95%CI: 2.55–6.82), P = 0.01; OR = 4.20 (95%CI: 3.55–8.50), P = 0.001].

CONCLUSION

Dysfunction or injury of the saccular macula and its pathways is prevalent in children with T1D. Optimum glycemic control is important to prevent diabetes related vestipulopathies.

Auditory and Vestibular Functioning in Individuals with Type-2 Diabetes Mellitus: A Systematic Review

Introduction  Diabetes mellitus is a metabolic disease associated with a rise in the level of blood glucose. Individuals with diabetes mellitus are more likely to develop hearing loss, tinnitus, and dizziness due to macro- and microvascular complications. The extent to which auditory and vestibular functions are impaired in individuals with type-2 diabetes mellitus is still under debate.

Objective  To systematically review studies focusing on auditory and vestibular functions in individuals with type-2 diabetes mellitus.

Data Synthesis  A search was conducted in the PubMed, MedlinePlus, Ingenta Connect and Google Scholar databases for articles published until June 2019. A total of 15,980 articles were primarily retrieved, 33 of which were shortlisted based on the inclusion criteria set by the investigators for the systematic review. Out of 33 full-length articles, 26 evaluated the functioning of the auditory system, while 7 evaluated the functioning of the vestibular system. Most studies related to auditory functioning reported a significant effect of type-2 diabetes mellitus on the peripheral auditory system, whereas studies on vestibular functioning reported no significant effect of diabetes mellitus on the functioning of the peripheral vestibular end-organ.

Conclusion  Overall, the results of various audiological and peripheral vestibular tests reveal distinctive peripheral and/or central auditory and vestibular end-organ impairments in individuals with type-2 diabetes mellitus.

Diabetes and the Vestibular System

Falls are among the most injurious, costly, and feared conditions affecting older adults. Patients with diabetes have a significantly greater risk for falling due to complications affecting the sensory systems required for balance: vision, proprioception, and vestibular. The effects of diabetes mellitus on the vestibular system are perhaps the least understood of these systems. The vestibular system is complex, includes multiple structures, and is difficult and expensive to thoroughly assess. There is pathophysiologic evidence suggesting a direct effect of diabetes mellitus complications on the vestibular system, but there is limited clinical evidence regarding which specific vestibular structures are most adversely affected. Nevertheless, large population-based studies show that patients with diabetes are more likely to have vestibular loss, have a high prevalence of a specific vestibular disorder called benign paroxysmal positional vertigo, and are at a greater risk for falling. Based on the available evidence, a balance screening and an evaluation of benign paroxysmal positional vertigo, a common but easy to treat pathology, in patients with diabetes is recommended as well as counseling on falls risk and home modifications.

Vestibular evoked myogenic potentials in patients with diabetes mellitus

Although the exact mechanism and most involved region of the vestibular system have not yet been fully clarified, vestibular dysfunction has been demonstrated in patients with diabetes mellitus (DM). Vestibular evoked myogenic potential (VEMP) is a short latency electromyographic response to sound or vibration stimuli that may reflect otolith organ or related reflex functions. Since its first description in 1992, VEMP has become a significant part of the vestibular test battery as an objective measurement tool. In diabetic patients, VEMP responses have been studied in order to determine any otolith organ or related reflex dysfunctions. Here, we review the literature with regard to VEMP findings representing any peripheral vestibular end-organ dysfunction in patients with DM. Distinctive vestibular end-organ impairments seem to be demonstrated in patients with DM either with or without DNP via objective vestibular testing tools including VEMP recordings according to relevant studies. However, further studies with larger sample sizes are required to reveal the more definitive findings of VEMP recordings regarding the vestibular pathologies in patients with DM.

Diabetes in the practice of otolaryngology

Diabetes mellitus is the most common endocrine disease, characterized by chronic hyperglycemia. The hyperglycemic milieu leads to endothelial injury in blood vessels of variant size, which results in microangiopathy and macroangiopathy (atherosclerosis). Consequential ischemia of nerves and hyperglycemia by itself lead to nerve degeneration and generalized neuropathy, affecting most often the sensory peripheral nerves and the autonomic nervous system. Auditory, vestibular and olfactory sensorium may be compromised by DM. People with DM have an increased susceptibility to infection, as a result of neutrophil dysfunction and impaired humoral immunity. Therefore DM predisposes to certain infectious diseases, such as fungal sinusitis or malignant otitis externa, which are rare in general population. Recovery from infections or from injuries may be compromised by coexisting DM. In this review we discuss complications of DM in the head and neck region. Otolaryngologists and general practitioners should be alert to specific conditions related to DM and be minded of the relevant complications and consequences.

Hyperglycemia and diabetes mellitus are related to vestibular organs dysfunction: truth or suggestion? A literature review

Diabetes mellitus is an independent risk factor for falling, particularly in the elderly. Due to chronic hyperglycemia and hyperinsulinemia patients with diabetes mellitus may have neurological deficits as peripheral neuropathy that is a debilitating micro-vascular complication affecting the proximal and distal peripheral sensory and motor nerves. Sensory neuropathy is prominent and represents the chief contributor to postural instability in diabetic subjects. Diabetic retinopathy is another complication consequent to a breakdown of the inner blood-retinal barrier with accumulation of extracellular fluids in the macula and growth of new vessels causing retinal detachment. Together peripheral neuropathy and retinopathy contribute to increase the risk of falls in diabetic patients, but a certain vestibular organs impairment should not be underestimated. Nevertheless, the exact mechanism and localization of peripheral vestibular damage consequent to chronic hyperglycemia and hyperinsulinemia are currently not still understood. Moreover it is not defined the possible role of these two blood conditions in worsening the prognosis of typical vestibular pathologies like "benign paroxysmal positional vertigo" and "Meniere disease". The aim of this review was to retrieve all studies investigating about the balance system alterations in patients suffering of diabetes. A search thorough Ovid MEDLINE was performed to enroll all eligible articles. Fourteen studies comprising a total of 1364 patients were included and analyzed in detail. On the basis of data reported in our review it appears plausible to hypothesize a direct connection among chronic hyperglycemic/hyperinsulinemic damage and peripheral vestibular organ dysfunction.

Otolith Dysfunction in Persons With Both Diabetes and Benign Paroxysmal Positional Vertigo

OBJECTIVE

Vestibular dysfunction is a well-recognized complication of type 2 diabetes (DM) that may contribute to increased fall risk. The prevalence of benign paroxysmal positional vertigo (BPPV) is higher in people with DM. The impact of DM on the otolith organs of the vestibular system in people with BPPV is unknown. The purpose of this study was to analyze otolith function using vestibular-evoked myogenic potential (VEMP) tests in people with DM and concurrent BPPV (BPPV + DM), and to examine the relationships between VEMP variables and diabetes-related variables.

STUDY DESIGN

Prospective, cross-sectional study.

SETTING

Tertiary academic medical center.

SUBJECTS AND METHODS

Participants 40 to 65 years were recruited in four groups: controls (n = 20), people with DM (n = 19), BPPV (n = 18), and BPPV + DM (n = 14). Saccule and utricle function were examined using cervical VEMP (cVEMP) and ocular VEMP (oVEMP), respectively. Diabetes-related variables such as HbA1c, duration of diabetes, and presence of sensory impairment due to diabetes were collected.

RESULTS

The frequency of abnormal cVEMP responses was higher in the DM (p = 0.005), BPPV (p = 0.003), and BPPV + DM (p <0.001) groups compared with controls. In the participants with diabetes, higher HbA1c levels were correlated with prolonged P1 (p = 0.03) and N1 latencies (p = 0.03). The frequency of abnormal oVEMP responses was not different between groups (p = 0.2).

CONCLUSION

Although BPPV and DM may independently affect utricle and saccule function, they do not seem to have a distinct cumulative effect.

Vascular and Neuroepithelial Histopathology of the Saccule in Humans With Diabetes Mellitus

HYPOTHESIS

This study aimed to determine if there are quantitative differences in the neuroepithelium and microvasculature of the saccule between subjects with and without diabetes mellitus (DM).

BACKGROUND

Histopathologic changes that may underlie the association between DM and vestibular dysfunction have not been characterized in humans.

METHODS

Human temporal bones (HTBs) from 39 subjects with DM (n = 16 type I DM [T1DM], n = 23 type II DM [T2DM]) were compared with 40 group age-matched controls. Vessel wall thickness was measured from the saccular arteriole. Type I and type II vestibular hair cell (VHC) counts were performed on perpendicularly oriented saccular maculae using differential interference contrast microscopy (T1DM: 5HTB/3 subjects; T2DM: 9HTB/8 subjects; controls: 25HTB/20 subjects).

RESULTS

The mean density of type I VHCs was 16 to 17% lower in the DM groups compared to controls (T1DM 52.21 [4.26], T2DM 53.3 [5.34], control 63.14 [2.49] cells/mm, p = 0.02). There were no differences between T1DM, T2DM, and control groups in type II VHC density (T1DM 40.89 [5.17], T2DM 40.44 [6.93], control 42.80 [1.79] cells/mm, p = 0.92) or in mean vessel wall thickness (T1DM 2.23 [0.62], T2DM 2.18 [0.53], control 2.00 [0.53] μm, p = 0.26).

CONCLUSION

Neuroepithelial pathology, manifested as lower density of type I VHCs, was observed in the saccules of subjects with DM. Saccular microangiopathy, expressed as alterations in arteriole thickness, was not observed. These findings are consistent with histologic observations in animals with experimentally induced diabetes. DM may have a selective and deleterious effect on human vestibular sensory epithelia.

Characterization of Vestibulopathy in Individuals with Type 2 Diabetes Mellitus

Objective

Previous observational studies suggest higher rates of vestibular dysfunction among patients with type 2 diabetes mellitus (DM) compared with those without diabetes. This study aims to functionally localize vestibular dysfunction in adults with type 2 DM.

Study Design

Prospective cohort study.

Setting

Tertiary academic medical center.

Subjects and Methods

Adults 50 years of age and older with ≥10-year history of type 2 DM were recruited (December 2011–February 2013, n = 25). Vestibular function was assessed by cervical and ocular vestibular-evoked myogenic potentials (VEMPs), testing the saccule and utricle, respectively. Head thrust dynamic visual acuity testing assessed semicircular canal (SCC) function in all canal planes. Results were compared with nondiabetic age-matched controls (n = 25).

Results

Subjects were 64.7 ± 7.6 years old, were 40% female, and had a mean hemoglobin A1c of 8.3% ± 1.7%. SCC dysfunction was more common than otoconial organ dysfunction, with 70% of subjects with DM demonstrating impaired performance of at least 1 SCC (ΔlogMAR ≥0.18) and 50% demonstrating otoconial organ impairment (absent ocular VEMP and/or cervical VEMP). Adults with type 2 DM had poorer lateral and superior SCC performance ( P < .05) but similar posterior SCC performance compared with controls ( P = .16). Both cervical VEMP peak-to-peak amplitude and ocular VEMP n1 amplitude were also decreased with diabetes ( P < .01).

Conclusion

Adults with type 2 DM have poorer performance on tests of vestibular function related to both SCC and otoconial organ function compared with nondiabetic age-matched adults. Future studies are needed to better understand the relationship between vestibular function and functional disability in persons with diabetes.

Epidemiology of vestibular evoked myogenic potentials: Data from the Baltimore Longitudinal Study of Aging

OBJECTIVE

To evaluate whether age-related changes in vestibular evoked myogenic potentials (VEMPs) differ by demographic and cardiovascular risk groups.

METHODS

Participants in the Baltimore Longitudinal Study of Aging underwent cervical and ocular VEMP testing. VEMP latency, amplitude, asymmetry ratios, and prevalence of absent responses were compared across demographic and cardiovascular risk groups.

RESULTS

In 257 participants (mean age 72.9, 57% female), ocular VEMP (oVEMP) n10 latency increased by 0.12ms/decade while amplitude decreased by 2.9μV/decade. Black participants had better oVEMP function (shorter latency, increased amplitude, and decreased odds of absent responses) relative to white participants. In 250 participants (mean age 72.6, 54% female), EMG-corrected cervical VEMP (cVEMP) amplitude decreased by 0.14μV/decade and p13 latency was 0.38ms longer in males. The odds of absent responses were significantly higher in individuals age ⩾80 for oVEMPs, and age ⩾70 for cVEMPs. Cardiovascular risk factors had no association with VEMP parameters.

CONCLUSIONS

We confirmed age-related declines in otolith function, and observed a protective effect of black race on oVEMP latency and amplitude.

SIGNIFICANCE

These results illustrate how measures of otolith function change with age in community-dwelling adults. Further investigations are needed to ascertain whether better otolith function in blacks might contribute to a lower risk of mobility disability and falls.

Electrophysiologic vestibular evaluation in type 2 diabetic and prediabetic patients: Air conduction ocular and cervical vestibular evoked myogenic potentials

OBJECTIVE

Chronically increased blood glucose levels may affect the vestibular system by damaging cells and neural structures in diabetes mellitus (DM). We aimed to search the effects of neurovascular degeneration on the vestibular system in type 2 DM and prediabetic patients by using air-conducted ocular (oVEMP) and cervical (cVEMP) vestibular evoked myogenic potentials.

DESIGN

Prospective study.

STUDY SAMPLE

Thirty diabetic, 30 prediabetic patients, and 31 age- and sex-matched controls having no peripheral or central vestibular disease, were enrolled. All participants were evaluated by audiovestibular tests, oVEMP, and cVEMP.

RESULTS

In the diabetic group, mean values of both oVEMP and cVEMP p1, n1 latencies were significantly longer compared to the prediabetic group and the control group, whereas latencies were similar in prediabetic and the control groups. Bilateral neural dysfunction was recognized in both tests and lateralization was not seen in VEMP asymmetric ratios. In the diabetic group, prevalence of pathological p1 and n1 latencies in oVEMP were 30.4% and 37.5%, whereas they were 53.7%, 59.3% in cVEMP, respectively. p1 latencies of cVEMP and oVEMP were positively correlated with HbA1c and fasting plasma glucose level in the diabetic group.

CONCLUSION

Subclinical vestibular neuropathy can be a newly defined diabetes-related complication.

Diabetes, vestibular dysfunction, and falls: analyses from the National Health and Nutrition Examination Survey

OBJECTIVE

Patients with diabetes are at increased risk both for falls and for vestibular dysfunction, a known risk factor for falls. Our aims were 1) to further characterize the vestibular dysfunction present in patients with diabetes and 2) to evaluate for an independent effect of vestibular dysfunction on fall risk among patients with diabetes.

STUDY DESIGN

National cross-sectional survey.

SETTING

Ambulatory examination centers.

PATIENTS

Adults from the United States aged 40 years and older who participated in the 2001-2004 National Health and Nutrition Examination Survey (n = 5,86).

INTERVENTIONS

Diagnosis of diabetes, peripheral neuropathy, and retinopathy.

MAIN OUTCOME MEASURES

Vestibular function measured by the modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces and history of falling in the previous 12 months.

RESULTS

We observed a higher prevalence of vestibular dysfunction in patients with diabetes with longer duration of disease, greater serum hemoglobin A1c levels and other diabetes-related complications, suggestive of a dose-response relationship between diabetes mellitus severity and vestibular dysfunction. We also noted that vestibular dysfunction independently increased the odds of falling more than 2-fold among patients with diabetes (odds ratio, 2.3; 95% confidence interval, 1.1-5.1), even after adjusting for peripheral neuropathy and retinopathy. Moreover, we found that including vestibular dysfunction, peripheral neuropathy, and retinopathy in multivariate models eliminated the significant association between diabetes and fall risk.

CONCLUSION

Vestibular dysfunction may represent a newly recognized diabetes-related complication, which acts as a mediator of the effect of diabetes mellitus on fall risk.