24 - Understanding the relationship between viscerocranial anatomy and dementia

Poster Board Number: 24
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Jay Bauman, PhD. - Assistant Professor, Center for Anatomical Science and Education, Saint Louis University; Meadow Campbell, PhD. - Assistant Professor, Center for Anatomical Science and Education, Saint Louis University

Abstract Body : Alzheimer’s dementia (AD) is the most common dementia-related diagnosis and affects 35 million people worldwide. Evidence suggests that hypoxia to the brain can result in neurodegeneration associated with AD. Hypoxia has been attributed to cardiovascular disease and its comorbidities. Additionally, cardiovascular disease has been associated with changes in viscerocranial morphology. The relationship between viscerocranial morphology and AD remains undefined, despite a well-documented association between cardiovascular disease and AD, as well as that of cardiovascular disease and viscerocranial morphology. In this study, we addressed this gap of knowledge by examining individuals with and without documented AD, using the hypothesis that the morphology of the nasal cavity in the AD group would impact oxygen delivery to tissues, setting a stage for hypoxic conditions and the eventual development of AD.

A set of pilot data consisting of 3D landmarks in the sagittal plane from the nasal cavity, nasopharynx, and cranial base were collected from CT scans of individuals with a history of AD (n = 20) and compared with an age- and sex-matched control group with no history of AD (n = 20). CT scans and diagnoses were obtained with permission from the New Mexico Decedent Image Database. Statistical analyses were carried out using PAST. To explore patterns of variation between samples, principal component analyses (PCA) were performed on the Procrustes-transformed landmarks. Univariate statistical analyses of the means and variance were analyzed for all landmarks

Results from the above analyses were mixed. Principal components analysis of Procrustes-transformed landmarks showed some separation between groups. PC1 explained 22.44% of the variance, PC2 12.37%, and PC3 11.29%. Landmarks that contributed the most to the analysis were prosthion, sphenoethmoidale, frontoethmoidale, and basion. While univariate statistical analyses revealed no statistically significant differences between groups for the mean nor variance in this set of pilot data, interesting trends in the position of those landmarks were observed. Individuals with positive scores on PC1 and PC2 exhibit superiorly placed nasal roofs, inferiorly placed anterior maxillae, and anterior-placed basion. This portion of the PC graph is occupied almost exclusively by the AD group. Such morphology may affect air flow and therefore oxygen delivery to tissues, including the brain.

Understanding the multifactorial etiology of AD is of great clinical importance. While the small sample sizes here did not statistically support the hypothesis, patterns of shape variation between AD and control groups were identified, suggesting the need for further investigation.