Vestibular end-organ impairment in an animal model of type 2 diabetes mellitus.
OBJECTIVE
To define and assess the functional impairment of the vestibular part of the inner ear in a diabetic state, using a direct and objective test for evaluating the vestibular end-organ and an animal model for diet-induced type 2 diabetes mellitus.


METHODS
Prospective controlled animal study.


METHODS
Two groups of sand rats (Psammomys obesus) were maintained on two different diets. The experimental group received a specially designed high-energy diet known to induce a diabetic state, and the control group a low-energy diet maintaining these animals in a normal metabolic state. After 1 month of documented hyperglycemia in the experimental group, recordings of vestibular evoked potentials (VsEPs) and recordings of auditory brainstem response (ABR) were conducted in all animals. The latency and the amplitude of the first wave of both responses, shown to reflect end-organ activity, were compared between the two groups.


RESULTS
The mean latency of the first wave of the VsEPs was significantly (P = .002) prolonged and the amplitude was significantly (P = .005) decreased in the diabetic group in comparison to the control group. The latency of the first wave of ABR was significantly (P = .02) prolonged, the amplitude was not significantly decreased, and threshold was significantly elevated (P = .01) in the diabetic group.


CONCLUSIONS
For the first time, using an objective assessment test, functional impairment of the vestibular part of the inner ear has been demonstrated in the diabetic metabolic state. Despite this being an animal study, these findings would seem to indicate that the vestibular-end-organ should be added to the long list of organs and tissues adversely affected by diabetes.
Perez
R
R
Department of Otolaryngology-Head and Neck Surgery, Shaare Zedek Medical Center, Jerusalem, Israel.
Ziv
E
E
Freeman
S
S
Sichel
J Y
JY
Sohmer
H
H
D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D004195:Disease Models, Animal; D005072:Evoked Potentials, Auditory / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005849:Gerbillinae; D006943:Hyperglycemia / Q000503:physiopathology; D007759:Labyrinth Diseases / Q000209:etiology; D011446:Prospective Studies; D011930:Reaction Time / Q000502:physiology; D018709:Statistics, Nonparametric; D014722:Vestibule, Labyrinth / Q000503:physiopathology*