Audiovestibular function in adults with type 2 Diabetes Mellitus

Abstract

Diabetes is one of the most prominent health emergencies of the 21st century affecting millions worldwide. Approximately 415 million individuals had diabetes in 2015, more than 10% living in the Sub-Saharan Africa region. Diabetes is a chronic illness and is classified according to aetiology. Type 2 diabetes accounts for more than 90% of cases. The disease is initially asymptomatic resulting in 30% to 85% of cases remaining undiagnosed. Due to the delayed diagnosis, approximately 20% of the individuals will have developed secondary complications. Disorders of the auditory and vestibular systems are often associated with diabetes; however, the extent and nature of these vestibular manifestations are still unknown. A main aim of this research study was to investigate the audiovestibular function, risk of falling and health related quality of life (HRQL) in adults with type 2 diabetes, compared to findings of non-diabetic age and gender matched controls. This was achieved through testing, the audiovestibular function (pure tone audiometry, video head impulse testing, and cervical and ocular vestibular evoked myogenic potentials), fall risk utilising three assessments (TUG, BBS and DGI), and HRQL utilising a self-administered (EQ-5D-5L). A cross-sectional research design was employed. A purposive sampling method was employed to recruit the type 2 diabetics. The mean age was 49.1 years (± 6.2), 57.1% were female and had an average BMI of 31.6 ±7.6 (p=<0.001; t-test).The HbA1c for the type 2 diabetic participants was 9.3% (±2.2) and had disease durations of 15.36 years (±9.67). No significant difference between the two groups was observed in the pure tone audiometry results. Although there was a significant difference between the two groups at 500Hz in the left ear (p=0.007; t-test), indicating poorer hearing for the type 2 diabetics. Overall, there were no significant difference between the two groups was observed in video head impulse testing. There was, however, a significant difference between the two groups in the presence of saccades for the right lateral canal (p=0.002; McNemar test of symmetry).The type 2 diabetics had a 1.5 times higher risk of having absent cVEMP results. Furthermore, the type 2 diabetics had a 1.3 times higher risk of having absent oVEMP results. For the cVEMPs, 53.6% of the type 2 diabetics cVEMPs were absent (unilateral/bilateral), compared to 25% of the non-diabetic controls. For the oVEMPs, 74.1% of the type 2 diabetics oVEMPs were absent (unilateral/bilateral), compared to 53.6% of the non-diabetic controls. A significant difference between the two groups was obtained for the averaged TUG test (p=0.046; t-test), indicating a risk of falling amongst the type 2 diabetics. There were no significant differences between the two groups in the BBS and DGI scores. There was no significant difference between the two groups for the EQ-5D-5L questionnaire. There was, however, a significant difference between the two groups for the health dimension mobility (p=0.032; t-test). The type 2 diabetic participants had a higher occurrence of audiovestibular dysfunction, higher risk of falling and poorer HRQL than the non-diabetic adults, and should be examined and monitored through the progression of the disease. If there are any auditory or vestibular involvements, further assessments should be considered to minimize the functional limitations of quality of life.