Longitudinal MRI and cognitive change in healthy elderly.

Abstract

Cross-sectional studies of normal aging indicate an association between memory and hippocampal volume, and between executive functioning and subcortical-frontal circuits. Much less is known, however, about the relationship between longitudinal MRI changes and cognitive decline. The authors hypothesized that longitudinal change in memory would be best predicted by change in hippocampal volumes, whereas change in executive functioning would be best predicted by cortical atrophy and progression of MRI markers of cerebrovascular disease. For this study, 50 healthy elderly subjects underwent structural MRI and cognitive testing at baseline and again at follow-up, with a mean follow-up interval of 45 months. Volumetric MRI measures were hippocampus, cortical gray matter, white matter signal hyperintensity (WMSH), and lacunae. Neuropsychological measures were psychometrically robust composite scores of episodic memory (MEM) and executive functioning (EXEC). Hierarchical multiple regression indicated that a decrease in hippocampus was associated with a decline in MEM, whereas decreased cortical gray matter and increased WMSH were independently associated with a decline in EXEC. Results suggest that in normal aging, cognitive functioning declines as cortical gray matter and hippocampus decrease, and WMSH increases. The association between WMSH and EXEC further highlights the cognitive sequealae associated with cerebrovascular disease in normal elderly.Correspondence concerning this article should be addressed to Joel H. Kramer , 1997). There are also age-related increases in subcortical ischemic vascular disease that can independently contribute to cognitive decline and dementia (Román, Erkinjuntti, Wallin, Pantoni, & Chui, 2002). Population-based studies have reported "silent" (i.e., asymptomatic) lacunae in 11%-28% of clinically asymptomatic elderly (Longstreth et al., 1998;Price et al., 1997;Vermeer et al., 2003), whereas the prevalence of white matter signal hyperintensities on MRI has ranged from 30% to 100% across studies of healthy elderly samples (Breteler et al., 1994;Longstreth et al., 1998;Ylikoski et al., 2000). Diffusion tensor MRIs have shown a progressive reduction in fractional anisotropy and an increase in diffusivity with age (Charlton et al., 2006).Despite the co-occurrence of age-related cognitive decline and brain changes, associations between brain volume and cognitive ability in healthy subjects have been difficult to establish. Although several studies have reported that hippocampal atrophy is associated with poorer episodic memory performance in older subjects (De Leon et al., 1997;Golomb et al., 1996), an extensive review and meta-analysis by Van Petten (2004) noted considerable variability across studies. The common correlation between hippocampal volume and memory performance across 33 studies was statistically significant but quite low, leading to the conclusion that the evidence for a positive relationship between hippocampal volume and memory performance was weak. Divergent result...

Brain volumetric changes and cognitive ageing during the eighth decade of life

“…Our results for loss of healthy grey and white matter accord with those of a previous study by Kramer et al [2007]. They showed, in a sample of 50 adults assessed across a near‐identical period of life to the participants in the present study (from approximate mean age 74 years to 78 years, though with a wider range than our sample), that grey matter atrophy was associated with declining executive function (a composite measure that included one of the same tasks used here to index Fluid Intelligence, WAIS Digit Span Backward).…”

“…They showed, in a sample of 50 adults assessed across a near‐identical period of life to the participants in the present study (from approximate mean age 74 years to 78 years, though with a wider range than our sample), that grey matter atrophy was associated with declining executive function (a composite measure that included one of the same tasks used here to index Fluid Intelligence, WAIS Digit Span Backward). Also consistent with our results, Kramer et al [2007] found no link between total grey matter volume decline and reductions in memory, indexed by tasks similar to ours, including a list‐learning test.…”

Metabolic Syndrome, Prediabetes, and Brain Abnormalities on MRI in Patients With Manifest Arterial Disease: The SMART-MR Study

“…This suggests that MetS induces brain changes comparable to accelerated aging. This is of clinical importance as the extent and rate of progression of global brain atrophy have been related to cognitive deterioration and conversion to dementia (28,29).…”

Impact of white matter hyperintensity volume progression on rate of cognitive and motor decline

“…The question as to whether there is likely to exist a differential effect of total WMH burden on age-related morbidity based on the location within the CNS of white matter change remains unanswered. Longitudinal studies looking at the progression of WMH have been reported [9][10][11][12][13][14][15][16][17][18][19] ; however, differences in methodologies of WMH measurement make comparisons difficult. A poor cor-relation in estimated WMH burden between differing visual rating scales 20 and increased reliability and sensitivity of WMH volumetric measurements 21 make studies using volumetric measures preferable to those that use visual rating scales.…”