Vestibular impairment in alzheimer's disease and mild cognitive impairment

In this study, it was aimed to examine the quantitative relationship between vestibular and cognitive functions in Alzheimer's disease (AD) and mild cognitive impairment (MCI) patients, in comparison with healthy controls (HCs). Comprehensive neuropsychological tests were applied to the patients and HCs. The vestibular system was evaluated with the video Head Impulse Test (vHIT) and vestibular evoked myogenic potentials (VEMPs). A total of 97 people participated in this study, including 31 AD, 34 MCI, and 32 HCs. Age was not statistically different between groups (p = 0.093). Disease duration was not statistically different between patient groups (p = 0.998). Each cognitive domain was statistically significant in separating the groups (p < 0.001). In vestibular tests, vHIT lateral canal gain is statistically lower in AD than in HCs (p = 0.019), and considering the number of people affected at least one semicircular canal, the rate of involvement is in AD (68%), MCI (59%) and HCs (31%), (p = 0.010). Executive functions (p = 0.024), attention (p = 0.004) and visuospatial functions (p = 0.039) were statistically different between the two affected and unaffected groups according to the state of involvement in the left posterior canal. Additionally, executive functions scores was statistically different between groups according to the effect on the posterior canal pair (p = 0.024). On the other hand, VEMPs responses were not statistically different both between groups and in cognitive functions. As a result of this study, it was found that vestibular disorders may have an impact on cognitive functions, the rate of vestibular involvement may increase as the severity of cognitive dysfunction in AD and MCI increases, and visual-spatial functions and MMSE may be related to vestibular involvement measured by vHIT.