title: Basal Forebrain Atrophy Contributes to Allocentric Navigation Impairment in Alzheimer's Disease Patients.
abstract: The basal forebrain degenerates in Alzheimer's disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants' ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy.
authors.affiliation: Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Kerbler
authors.affiliation: Memory Clinic, Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital , Prague , Czech Republic ; International Clinical Research Center, St. Anne's University Hospital Brno , Brno , Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Nedelska
authors.affiliation: Computational Informatics, Commonwealth Scientific and Industrial Research Organisation , Brisbane, QLD , Australia.
authors.forename: Jurgen
authors.initials: J
authors.lastname: Fripp
authors.affiliation: Memory Clinic, Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital , Prague , Czech Republic ; International Clinical Research Center, St. Anne's University Hospital Brno , Brno , Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Laczó
authors.affiliation: Memory Clinic, Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital , Prague , Czech Republic ; International Clinical Research Center, St. Anne's University Hospital Brno , Brno , Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Vyhnalek
authors.affiliation: Department of Radiology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital , Prague , Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Lisý
authors.affiliation: Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Hamlin
authors.affiliation: Computational Informatics, Commonwealth Scientific and Industrial Research Organisation , Brisbane, QLD , Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Rose
authors.affiliation: Memory Clinic, Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital , Prague , Czech Republic ; International Clinical Research Center, St. Anne's University Hospital Brno , Brno , Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Hort
authors.affiliation: Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland , Brisbane, QLD , Australia.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Coulson
keywords: Alzheimer’s disease; MRI; basal forebrain; cognitive impairment; navigation