Neuroanatomical correlates of olfactory loss in normal aged subjects

• Published in: Behavioural brain research Vol. 246; pp. 148 - 153
• Main Authors: Segura, Bàrbara, Baggio, Hugo César, Solana, Elisabeth, Palacios, Eva M., Vendrell, Pere, Bargalló, Núria, Junqué, Carme
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01.06.2013; Elsevier
• Subjects: Aged; Aging; Anisotropy; Behavioral psychophysiology; Biological and medical sciences; Brain Mapping; Cortical thickness; Diffusion Magnetic Resonance Imaging; DTI; Female; Fundamental and applied biological sciences. Psychology; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; MRI; Nerve Fibers, Myelinated - physiology; Neuroanatomy; Neuropsychological Tests; Olfaction Disorders - pathology; Olfactory deficits; Olfactory Pathways - pathology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Smell - physiology; UPSIT; VBM; Verbal Learning - physiology; VBM; UPSIT; Cortical thickness; MRI; DTI; Aging; Olfactory deficits; Human; Cerebral cortex; Senescence; Central nervous system; Layer thickness; Nuclear magnetic resonance imaging; Encephalon; Olfaction
• ISSN: 0166-4328; 1872-7549; 1872-7549
• DOI: 10.1016/j.bbr.2013.02.025

► Olfactory loss is associated in normal aged subjects with gray and white matter brain changes. ► DTI shows microstructural changes in superior longitudinal fasciculi and corpus callosum. ► VBM shows GM volume loss in entorhinal and perirhinal olfactory structures. In non-demented older persons, smell dysfunction, measured premortem, has been associated with postmortem brain degeneration similar to that of Alzheimer's disease. We hypothesized that distinct measures of gray and white matter integrity evaluated through magnetic resonance imaging (MRI) techniques could detect degenerative changes associated with age-related olfactory dysfunction. High-resolution T1-weighted images and diffusion-tensor images (DTI) of 30 clinically healthy subjects aged 51–77 were acquired with a 3-Tesla MRI scanner. Odor identification performance was assessed by means of the University of Pennsylvania Smell Identification Test (UPSIT). UPSIT scores correlated with right amygdalar volume and bilateral perirhinal and entorhinal cortices gray matter volume. Olfactory performance also correlated with postcentral gyrus cortical thickness and with fractional anisotropy and mean diffusivity levels in the splenium of the corpus callosum and the superior longitudinal fasciculi. Our results suggest that age-related olfactory loss is accompanied by diffuse degenerative changes that might correspond to the preclinical stages of neurodegenerative processes.