Impairment in the Sensorineural Elements of the Cochlea and Vasculature in Diabetes Mellitus :a Human Temporal Bone Study
Aims/hypothesis : To evaluate impairment in the sensorineural elements of the cochlea in patients with type 2 diabetes mellitus his top athologically. Methods : Temporal bones from 18 patients (mean age, 52.8 years) with type 2 diabetes mellitus and ones from 26 age-matched normal subjects (mean age, 52.9) were examined by light microscopy. Thickening of the walls of the cochlear vessels, the percentage of loss of cochlear hair cells and the number of spiral ganglion cells were compared between the groups. Results : In the diabetes group, the walls of the vessels of the basilar membrane in all turns (P < 0.01) were significantly thicker than those in controls. Loss of cochlear outer hair cells was significantly greater in the lower basal (P<0.001), upper basal and lower middle turns (P< 0.05) in the diabetic group. There was no significant difference in the number of spiral ganglion cells or inner hair cells between the groups. Conclusion/interpretation : This study demonstrates that there is cochlear microangiopathy and degeneration of cochlear outer hair cells in patients with type 2 diabetes mellitus.
