Changes in the cochlear and retrocochlear parts of the auditory system in 19–39 and 40–60 years old patients with type 1 diabetes mellitus

Abstract

Pathophysiological alterations in the cochlea and functional tests of the auditory pathway support that in diabetes both vasculopathy and neural changes could be present. The aim of our research was to study the differential effect of type 1 diabetes mellitus (T1DM) on two different age groups. Audiological investigation was carried out in 42 patients and 25 controls at the same age groups. Investigation of the conductive and sensorineural part of the hearing system by pure tone audiometry, distortion product otoacoustic emission measurement and acoustically evoked brainstem response registration were evaluated. Among the 19-39-year-old people the incidence of hearing impairment was not different in the diabetes and control groups. Among the 40-60-year-old people hearing impairment was more common in the diabetes group (75%) than in the control group (15,4%). Among patients with type 1 diabetes, the mean threshold values were higher in both age groups at all frequencies although significant difference was in 19–39 years old group: 500-4000Hz right ear, 4000Hz left ear, in 40–60 years old group: 4000–8000 Hz both ears. In the 19–39 years old diabetes group only at 8000 Hertz on the left side was a significant (p<0,05) difference in otoacoustic emissions. In the 40–60 years old diabetes group significantly less otoacoustic emissions at 8000 Hz on the right side (p<0,01) and at 4000-6000-8000 Hertz on the left side, (p<0,05, p<0,01, p<0,05 respectively) was present compared to the control group. According to ABR (auditory brainstem response) latencies and wave morphologies, a possible retrocochlear lesion arose in 15% of the 19–39 years old and 25% of the 40–60 years old diabetes group. According to our results, T1DM affects negatively the cochlear function and the neural part of the hearing system. The alterations are more and more detectable with aging.

A systematic review of the association of Type I diabetes with sensorineural hearing loss

“…However, this was not statistically significant (p = 0.4538). This demonstrates that T1D may damage the hearing system, and this effect may increase with age [81].…”

“…The two studies found there was a significant difference between PTAs [80,81], but one found there was no significant difference [83]. Additionally, one study found there was a significant difference in thresholds between the groups [81], but another study did not [82]. However, results showed that PTAs and OAEs were significantly worse in older diabetic individuals compared to younger subjects, indicating an association with age [81].…”

“…The four studies evaluated suggest that there are differences in the auditory system between patients with T1D and healthy controls, but many results were heterogenous. The two studies found there was a significant difference between PTAs [80,81], but one found there was no significant difference [83]. Additionally, one study found there was a significant difference in thresholds between the groups [81], but another study did not [82].…”

“…Additionally, one study found there was a significant difference in thresholds between the groups [81], but another study did not [82]. However, results showed that PTAs and OAEs were significantly worse in older diabetic individuals compared to younger subjects, indicating an association with age [81]. Also, high levels of HbA1C correlated with an increase in speech and high-frequency SNHL [83].…”

“…Horva ´th et al also conducted a prospective observational study to evaluate changes in the auditory system in patients with T1D [81]. In this study, forty-two patients with a diagnosis of T1D were included and were matched with 25 non-diabetic controls.…”