Longitudinal magnetic resonance imaging studies of older adults: A shrinking brain

Laboratory of Personality and Cognition, National Institute on Aging, Baltimore, Maryland 21224-6825, USA.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 05/2003; 23(8):3295-301.
Source: PubMed

ABSTRACT Age-related loss of brain tissue has been inferred from cross-sectional neuroimaging studies, but direct measurements of gray and white matter changes from longitudinal studies are lacking. We quantified longitudinal magnetic resonance imaging (MRI) scans of 92 nondemented older adults (age 59-85 years at baseline) in the Baltimore Longitudinal Study of Aging to determine the rates and regional distribution of gray and white matter tissue loss in older adults. Using images from baseline, 2 year, and 4 year follow-up, we found significant age changes in gray (p < 0.001) and white (p < 0.001) volumes even in a subgroup of 24 very healthy elderly. Annual rates of tissue loss were 5.4 +/- 0.3, 2.4 +/- 0.4, and 3.1 +/- 0.4 cm3 per year for total brain, gray, and white volumes, respectively, and ventricles increased by 1.4 +/- 0.1 cm3 per year (3.7, 1.3, 2.4, and 1.2 cm3, respectively, in very healthy). Frontal and parietal, compared with temporal and occipital, lobar regions showed greater decline. Gray matter loss was most pronounced for orbital and inferior frontal, cingulate, insular, inferior parietal, and to a lesser extent mesial temporal regions, whereas white matter changes were widespread. In this first study of gray and white matter volume changes, we demonstrate significant longitudinal tissue loss for both gray and white matter even in very healthy older adults. These data provide essential information on the rate and regional pattern of age-associated changes against which pathology can be evaluated and suggest slower rates of brain atrophy in individuals who remain medically and cognitively healthy.

Download full-text


Available from: Alan Zonderman, Mar 03, 2014
71 Reads
  • Source
    • "For example, delayed PFC maturation (Sowell et al., 1999) may explain, in part, why young adults engage in more risky decisionmaking under stress than older adults do (Mather et al., 2009). Conversely , age-related decreases in GMV and WMV are also apparent (e.g., Hedden and Gabrieli, 2004; Lupien et al., 2007; Madden et al., 2009; Resnick et al., 2003), particularly between middle and late adulthood (Raz et al., 2005) and have been linked to " cascading " or cumulative effects of stress and glucocorticoids (e.g., Goosens and Sapolsky, 2010; Oitzl et al., 2010). Consequently, future research on associations between individual differences in stress and brain structures is needed, particularly in non-clinical samples over age 50. "
    • "Differences in reported results are frequent as cohorts and methods used to study aging greatly vary among studies. The most optimal way to assess genuine age-related changes is to perform longitudinal studies in which the effect of age is examined within subjects over time (Resnick et al., 2003; Scahill et al., 2003; Raz et al., 2004, 2005; Dotson et al., 2009; Driscoll et al., 2009; Fjell et al., 2009; Marcus et al., 2010; Thambisetty et al., 2010). Unfortunately, such studies are rare – because of their cost and attrition bias – and not yet capable of addressing age-related brain differences over several decades. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Hippocampal atrophy, as evidenced using magnetic resonance imaging (MRI), is one of the most validated, easily accessible and widely used biomarkers of Alzheimer's disease (AD). However, its imperfect sensitivity and specificity have highlighted the need to improve the analysis of MRI data. Based on neuropathological data showing a differential vulnerability of hippocampal subfields to AD processes, neuroimaging researchers have tried to capture corresponding morphological changes within the hippocampus. The present review provides an overview of the methodological developments that allow the assessment of hippocampal subfield morphology in vivo, and summarizes the results of studies looking at the effects of AD and normal aging on these structures. Most studies highlighted a focal atrophy of the CA1 subfield in the early (predementia or even preclinical) stages of AD, before atrophy becomes more widespread at the dementia stage, consistent with the pathological literature. Preliminary studies have indicated that looking at this focal atrophy pattern rather than standard whole hippocampus volumetry improves diagnostic accuracy at the Mild Cognitive Impairment (MCI) stage. However, controversies remain regarding changes in hippocampal subfield structure in normal aging and regarding correlations between specific subfield volume and memory abilities, very likely because of the strong methodological variability between studies. Overall, hippocampal subfield analysis has proven to be a promising technique in the study of AD. However, harmonization of segmentation protocols and studies on larger samples are needed to enable accurate comparisons between studies and to confirm the clinical utility of these techniques. Copyright © 2015. Published by Elsevier Ltd.
    Neuroscience 08/2015; DOI:10.1016/j.neuroscience.2015.08.033 · 3.36 Impact Factor
  • Source
    • "More specifically, at the functional level, it could be predicted that older bilingual adults should utilize the ACC more efficiently than monolingual older controls exhibiting relatively less ACC activation during domain-general executive control tasks. Moreover, despite the general neural decline in gray and white matter observed in aging (Good et al., 2001; Raz, 2005; Resnick et al., 2003), older bilingual adults should show increased GM density than older monolingual controls in areas engaged during cognitive control. In other words, speaking two or more languages might be representative of one of the cognitive activities that can boost cognitive reserves, leading to better behavioral performance. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Healthy non-pathological aging is characterized by cognitive and neural decline, and although language is one of the more stable areas of cognition, older adults often show deficits in language production, showing word finding failures, increased slips of the tongue, and increased pauses in speech. Overall, research on language comprehension in older healthy adults show that it is more preserved than language production. Bilingualism has been shown to confer a great deal of neuroplasticity across the life span, including a number of cognitive benefits especially in executive functions such as cognitive control. Many models of bilingual language processing have been proposed to explain bilingual language processing. However, the question open of how such models might be modulated by age-related changes in language. Here, we discuss how current models of language processing in non-pathological aging, and models of bilingual language processing can be integrated to provide new research directions.
Show more