title: Reduced functional reserve in patients with age-related white matter changes: a preliminary FMRI study of working memory.
abstract: Subcortical age-related white matter changes (ARWMC) are a frequent finding in healthy elderly people suggested to cause secondary tissue changes and possibly affecting cognitive processes. We aimed to determine the influence of the extent of ARWMC load on attention and working memory processes in healthy elderly individuals. Fourteen healthy elderly subjects (MMSE >26; age 55-80 years) performed three fMRI tasks with increasing difficulty assessing alertness, attention (0-back), and working memory (2-back). We compared activation patterns in those with only minimal ARWMC (Fazekas 0-1) to those with moderate to severe ARWMC (Fazekas 2-3). During the fMRI experiments, the study population showed activation in brain areas typically involved in attention and working memory with a recruitment of cortical areas with increasing task difficulty. Subjects with higher lesion load showed a higher activation at all task levels with only sparse increase of signal with increasing complexity. In the lower lesion load group, rising task difficulty lead to a significant and widely distributed increase of activation. Although the number of patients included in the study is small, these findings suggest that even clinically silent ARWMC may affect cognitive processing and lead to compensatory activation during cognitive tasks. This can be interpreted as a reduction of functional reserve and may pose a risk for cognitive decline in these patients.
authors.affiliation: Department of Neurology, MR Research Neurology, UniversitätsMedizin Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Griebe
authors.affiliation: Department of Neurology, University Hospital Basel, Basel, Switzerland; Division of Diagnostic and Interventional Neuroradiology, Department of Radiology, Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Amann
authors.affiliation: Fraunhofer MEVIS, Institute for Medical Image Computing, Bremen, Germany.
authors.forename: Jochen G
authors.initials: JG
authors.lastname: Hirsch
authors.affiliation: Department of Neurology, University Hospital Basel, Basel, Switzerland.
authors.forename: Lutz
authors.initials: L
authors.lastname: Achtnichts
authors.affiliation: Department of Neurology, MR Research Neurology, UniversitätsMedizin Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hennerici
authors.affiliation: Department of Neurology, MR Research Neurology, UniversitätsMedizin Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Gass
authors.affiliation: Department of Neurology, MR Research Neurology, UniversitätsMedizin Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Szabo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D001288:Attention; D001931:Brain Mapping; D003072:Cognition Disorders / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D066127:White Matter / Q000473:pathology*