Cochlear changes in patients with type 1 diabetes mellitus.

OBJECTIVE

To evaluate the effects of diabetes on cochlear elements in human beings.

STUDY DESIGN AND SETTING

Twenty-six temporal bones (mean age, 37.5 years) with type 1 diabetes and 30 age-matched controls were examined by light microscopy. We compared the findings of cochlear vessels, hair cells, spiral ganglion cells, and cochlear lateral walls.

RESULTS

In diabetics, the walls of vessels of the basilar membrane (P < 0.001) and vessels of the stria vascularis were (P < 0.01) significantly thicker in all turns and loss of outer hair cells (OHCs) was significantly greater in the lower basal turn (P < 0.01). Atrophy of the stria vascularis in all turns (P < 0.0001) and loss of spiral ligament cells in upper turns (P < 0.01) were significantly higher than controls. No significant difference was obtained in the number of spiral ganglion cells between groups.

CONCLUSION

This study suggests that type 1 diabetes mellitus can cause cochlear microangiopathy and subsequently degeneration of cochlear lateral walls and OHCs.