Structure and volume of the olfactory brain: relationships to olfactory dysfunction, cognitive decline, and prospective dementia

PI: Erika Laukka, erika.jonsson.laukka@ki.se

Recent evidence suggests that olfactory performance can partly be explained by the architecture of the olfactory brain. Aging takes a toll on olfactory functions. It is thus valuable to identify predictors of olfactory decline in older populations to clarify why some older adults retain an intact sense of smell whereas others experience significant reduction or loss of this important sense. In addition, impaired olfactory abilities are often prevalent in early stages of dementia and Alzheimer’s disease. Alterations in olfactory brain regions may thus serve as early markers for cognitive decline and future dementia.

The general aim of this research program is to investigate how brain structures are related to olfactory performance. Specifically, we will investigate whether longitudinal data (i.e. data on the same people gathered over time) support previous findings based on cross-sectional data (i.e. data gathered at one point in time) that a smaller olfactory bulb is correlated with a worse sense of smell. We will also investigate whether having a smaller olfactory bulb is associated with loss of the sense of smell in old age and whether it can predict cognitive impairment and dementia six years later.

These questions will be addressed with data from a large population-based sample of people aged 60 years and older, the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). This project has unique longitudinal data on health, cognitive functions, olfactory abilities, genetics, and brain imaging. The data will be analyzed in collaboration with Thomas Hummel at Dresden University.

The findings of this project will help to deepen our understanding of olfactory dysfunction and its relationship with cognitive decline and dementia.

The program is funded by a grant from the Swedish Research Council.