Odor identification deficit in mild cognitive impairment and Alzheimer's disease is associated with hippocampal and deep gray matter atrophy. (30th September 2016)

• Record Type: Journal Article
• Authors: Hagemeier, Jesper; Woodward, Matthew R.; Rafique, Usama A.; Amrutkar, Chaitanya V.; Bergsland, Niels; Dwyer, Michael G.; Benedict, Ralph; Zivadinov, Robert; Szigeti, Kinga
• Is Part Of: Psychiatry research. Volume 255(2016)
• Page Start: 87
• Page End: 93
• Publication Date: 2016-09-30
• Subjects: Olfactory -- Smelling -- MRI -- Alzheimer's -- Mild cognitive impairment -- Deep gray matter; Psychiatry -- Periodicals; Brain -- Imaging -- Periodicals; Psychiatry -- Periodicals; Diagnostic Imaging -- Periodicals; Psychiatrie -- Périodiques; Cerveau -- Imagerie pour le diagnostic -- Périodiques; 616.890754
• DOI: 10.1016/j.pscychresns.2016.08.003
• Languages: English
• ISSNs: 0925-4927

Abstract

Abstract: Even in early stages, Alzheimer's disease (AD) is associated with olfactory deficit. We assess the association of volumetric differences in subcortical deep gray matter (DGM) structures and odor identification deficit (OID) in subjects with amnestic mild cognitive impairment (aMCI), AD and normal controls (NCs), and relate findings to the current gold standard right sided memory measure, visual reproduction. Eighty subjects (19 aMCI; 42 CE; 19 NC) were included in this study. We obtained olfactory testing and normalized structural brain volumes from 3T T1 MRI scans. Associations between MRI, olfactory- and memory impairment were studied using Pearson- and partial-correlation adjusted for age. AD patients had significantly higher olfactory deficits, lower visual reproduction scores, and reduced brain volumes ( p <0.05). Within aMCI, OID was associated with lower right hippocampal- and left amygdala volume ( p <0.05). In AD, OID was associated with bilaterally lower hippocampus and left amygdala volumes. In contrast, visual reproduction was associated with bilateral volume loss regardless of study group. OID is a more specific marker of early pathological right mesial-temporal involvement than the currently regarded gold standard of right sided-memory (visual reproduction). OID may be valuable in the longitudinal evaluation of disease modifying treatments in early disease course. Highlights: Odor Identification, visual reproduction and volume MRI were obtained for AD, MCI and controls. AD patients had significantly higher olfactory deficits and reduced brain volumes. Already in aMCI, OID was significantly associated to lower right hippocampal volume. OID is a more specific marker of early right mesiotemporal involvement than visual reproduction.