Vestibular Deficits with Type 2 Diabetes Assayed by Motion Perception Thresholds

Abstract

Postural control depends on the coordinated action of many physiologic systems, and sensory feedback about body motion plays a critical role. Individuals with diabetes have increased postural sway and risk of falling. Many studies have implicated somatosensory neuropathy, but a vestibular role has also been suggested. To further explore vestibular deficits, we measured vestibular perceptual thresholds in subjects with type 2 diabetes. These thresholds quantify the smallest motion that an individual can reliably sense. We selected this approach because thresholds are sensitive to pathology, age and balance test performance. We tested four human subjects (ages 52-69, one female) who received a diagnosis of type 2 diabetes between 12 and 17 years before testing. Subjects were not screened for neuropathy or blood sugar control (HbA1c: 6.8, 9.1, 13 and 7.6). Thresholds were tested with the subject sitting in a chair on a moving platform with the head held firmly by a helmet. The platform repeatedly exposed subjects to small motions and subjects reported their perception (“press the button in your left hand if you thought you moved to the left and the button in your right hand if you thought you moved to the right.”) Motion amplitudes were adaptively adjusted to find the stimulus amplitude at which subjects were about 80% correct. Five motion conditions were tested. Subjects with diabetes had higher thresholds than published normative data (repeated-measures ANOVA, p=0.0059): +36% for yaw rotation, +15% for lateral translation, +220% for vertical translation, +13% for roll tilt (1 s motions), +3% for roll tilt (5 s motions). These results emphasize the need for further studies on the effects of diabetes on the vestibular system. Disclosure S. King: None. D.J. Wexler: None. T. Leeder: None. F. Karmali: Employee; Spouse/Partner; Biogen.