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.