Some of the most impressive functional specialization in the human brain is found in occipitotemporal cortex (OTC), where several areas exhibit selectivity for a small number of visual categories, such as faces and bodies, and spatially cluster based on stimulus animacy.Previous studies suggest this animacy organization reflects the representation of an intuitive taxonomic hierarchy, distinct from the presence of face-and body-selective areas in OTC.Using human fMRI, we investigated the independent contribution of these two factors -the face-body division and taxonomic hierarchy -in accounting for the animacy organization of OTC, and whether they might also be reflected in the architecture of several deep neural networks. We found that graded selectivity based on animal resemblance to human faces and bodies masquerades as an apparent animacy continuum, which suggests that taxonomy is not a separate factor underlying the organization of the ventral visual pathway.

Importance: Given the rising prevalence of patients with dementia and those at risk for it, early identification is prioritized. As vestibular dysfunction is associated with Alzheimer’s disease (AD) and may contribute to its onset, vestibular assessment may yield an opportunity in early dementia screening. Objective: This systematic review structures and compares the different raw outcome measures used to assess vestibular function while comparing older adults with preserved cognition to individuals with cognitive impairment, either suffering from mild cognitive impairment (MCI) or AD. Design: Two investigators independently and systematically searched publications performing objectively measured vestibular testing in a patient population consisting of either MCI or AD, compared with a control group of older adults with preserved cognition. No limitations regarding language or publication date were applied. References of the retrieved articles were hand searched for relevant articles. Results: Seven articles were included for analysis. A total of 235 older adults with impaired cognition (150 AD, 85 MCI) were compared with a control group of 481 older adults with preserved cognition. Evaluation of the peripheral vestibular function included video head impulse test (vHIT), videonystagmography (VNG), electronystagmography (ENG) including bithermal caloric irrigation and vestibular evoked myogenic potentials (VEMP). The VEMP test, assessing otolith function and the elicited vestibulocollic reflex (VCR), was able to differentiate subjects with AD and its prodromal stage from healthy controls, with p13 latency (p < 0.05) and amplitude (p < 0.05) having the most discriminating power. No correlation between cognitive decline and vestibulo-ocular reflex measurements in different frequency ranges of the semicircular canals (using vHIT, rotatory chair testing, and caloric irrigation) was found. Because of the limited number of available studies and the large heterogeneity in outcome measures, these results have to be interpreted with caution. Conclusions: Measurements of the VCR, as evoked by the VEMP test, discriminate between patients with cognitive impairment (MCI and AD) and older adults with preserved cognition, whereas measurements of the vestibulo-ocular reflex do not. More studies are needed to further elaborate on these findings.

IntroductionDementia is a prevalent disease affecting a growing number of the ageing population. Alzheimer’s disease (AD) is the most common cause of dementia. Previous research investigated the link between hearing loss and cognition, and the effect of vestibular dysfunction on cognition. Hearing loss and, to a lesser extent, vestibular decline both result in a decreasing cognitive function. However, their interaction should not be underestimated. The aim of this study is to assess the effect of hearing loss, vestibular decline and their interaction on cognition in people suffering from mild cognitive impairment (MCI) and dementia due to AD (ADD).Methods and analysisWe designed a prospective longitudinal study to assess the effect of hearing loss and vestibular decline on cognition. A total of 100 cognitively impaired elderly (between 55 and 84 years of age), consisting of 60 patients with MCI due to AD and 40 patients with ADD will be included. The control group will consist of individuals with preserved cognition group-matched based on age, hearing level and vestibular function. A comprehensive assessment is performed at baseline, 12-month and 24-month follow-ups. The primary outcome measure is the change in the Repeatable Battery for the Assessment of Neuropsychological Status adjusted for Hearing-impaired individuals total score, a cognitive test battery assessing different cognitive domains. Secondary outcome measures include additional neuropsychological assessments, cortical auditory-evoked potentials, and evaluation of general and disease-specific health-related quality of life. Variables include cognitive, audiological and vestibular evaluation. Variance analyses will assess the effect of hearing loss and vestibular decline on cognition. More precisely, the link between hearing loss and non-spatial cognitive functioning, the effect of vestibular decline on spatial cognition and the impact of both factors on the rate of conversion from MCI due to AD to ADD will be investigated.Ethics and disseminationThe study protocol was approved by the ethical committee of the Antwerp University Hospital on 4 February 2019 with protocol number B300201938949. The findings will be disseminated through peer-reviewed publications and conference presentations.Trial registration numberClinicalTrials.gov Registry (NCT04385225).

Key Points Question Is bilateral vestibulopathy (BV) associated with cognitive function in older adults? Findings In this cross-sectional study including 34 participants with BV and 34 age-, sex-, and hearing performance–matched controls, participants with BV had worse cognitive function in general, which was most pronounced in the subdomains of immediate memory, visuospatial cognition, and attention. Meaning These findings support existing evidence on an association between vestibular loss and cognitive impairment.

Background: DeaFNess Autosomal dominant 9 (DFNA9) is a hereditary disorder known to affect both hearing and vestibular function in its carriers. Its phenotype is characterized by progressive sensorineural hearing loss (SNHL) and vestibular dysfunction evolving towards bilateral vestibulopathy (BV) by the 3rd to 5th life decade. Recent studies have identified the impact of hearing loss and vestibular dysfunction on cognitive functioning. Objective: The main objective of this study was to investigate how the cognitive functioning of carriers of the p.Pro51Ser variant in the COCH gene is affected by the disease and compare these results with a matched healthy control group. Study design: Forty-six carriers of the pathogenic p.Pro51Ser variant in the COCH gene were included in this study, of which 38 met the Bárány Society criteria and were thus diagnosed with BV. All subjects were between the age of 22 and 72 years old. Each control was individually matched based on age, gender, and education level. A cognitive, vestibular, and hearing assessment was performed in all subjects. All participants completed the Repeatable Battery for the Assessment of Neuropsychological Status, adjusted for the Hearing Impaired (RBANS-H), a cognitive test battery that includes subtests probing Immediate and Delayed Memory, Visuospatial/Constructional, Language, and Attention. Results: Overall, the DFNA9 patients demonstrated significantly lower scores on the Immediate Memory subscale and lower Total Scale scores than their healthy matched controls. The total sample was divided into two groups: age <55 years old and age ≥55 years old. The DFNA9 group aged ≥55 years old obtained significantly lower scores on the Attention subscale and lower Total Scale scores than their matched controls. Cognition of DFNA9 patients aged <55 years old no longer differed significantly from their matched controls. Conclusion: This cross-sectional study found that DFNA9 patients demonstrated cognitive deficits in comparison with their healthy matched controls. The DFNA9 group aged ≥ 55 years old obtained significantly lower scores on the Total Scale and Attention subscale. This finding; however, was not observed for the age group younger than 55 years old. Further research is needed on the individual trajectory of SNHL and vestibular function, and how hearing rehabilitation affects cognitive functioning.