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

Johns Hopkins University, Baltimore, Maryland, United States
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

Full-text

Available from: Alan Zonderman, Mar 03, 2014
  • Source
    • "However, the use of endocasts to study the fossil record also has advantages over the use of other anatomical parts. For instance, a number of studies have demonstrated a significant agerelated reduction in total brain volume (Resnick et al., 2003; Kochunov et al., 2005; Rettmann et al., 2006), suggesting that the shape of the endocranial cast reflects the shape of the brain of a fully grown adult. Therefore, comparative morphological studies of adult fossil endocasts compare specimens of the same developmental stage, which corresponds to normal brain growth completion . "
    [Show abstract] [Hide abstract]
    ABSTRACT: The evolutionary history of the genus Homo is the focus of major research efforts in palaeoanthropology. However, the use of palaeoneurology to infer phylogenies of our genus is rare. Here we use cladistics to test the importance of the brain in differentiating and defining Neandertals and modern humans. The analysis is based on morphological data from the calvarium and endocast of Pleistocene fossils and results in a single most parsimonious cladogram.
    Full-text · Article · Jan 2016 · Journal of Human Evolution
    • "Findings from the present study suggest that advanced age is associated with significantly smaller GM and hippocampal volumes, with a continuous age trend similar to that observed in the young elderly. In longitudinal studies (with N ≥50 and mean age ≥70 years), the estimated rates of total brain atrophy range from 5.0% to 7.7% per decade (Driscoll et al., 2009;Goldstein et al., 2005;Resnick et al., 2003;Silbert et al., 2008), with the exception of one study which reported rates of atrophy as large as 21.0% per decade in participants in their 80s (Tang et al., 2001). Moreover, many longitudinal studies revealed accelerated atrophy in both total GM volume and hippocampus from age 60 years onwards (Driscoll et al., 2009;Hedman et al., 2012;Raz et al., 2005;Raz et al., 2010;Scahill et al., 2003). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Successful brain aging in the oldest old (≥90 years) is under-explored. This study examined cross-sectional brain morphological differences from eighth to eleventh decades of life in non-demented individuals by high-resolution magnetic resonance imaging. 277 non-demented community dwelling participants (71-103 years) from Sydney Memory and Ageing Study and Sydney Centenarian Study comprised the sample, including a subsample of 160 cognitively high-functioning elders. Relationships between age and MRI-derived measurements were studied using general linear models; and structural profiles of the ≥90 years were delineated. In full sample and the sub-sample, significant linear negative relationship of grey matter with age was found, with the greatest age effects in the medial temporal lobe and parietal and occipital cortices. This pattern was further confirmed by comparing directly the ≥90 years to the 71-89 years groups. Significant quadratic age effects on total white matter and white matter hyperintensities were observed. Our study demonstrated heterogeneous differences across brain regions between the oldest old and young old, with an emphasis on hippocampus, temporo-posterior cortex and white matter hyperintensities.
    No preview · Article · Jan 2016
  • Source
    • "Advancing age is associated with structural brain changes, even in the absence of dementia or other pathological conditions (Raz et al., 2007a). The frontal and temporal lobes are most affected, with many studies showing disproportionate changes in regions within the prefrontal cortex (Small et al., 2000;Liu et al., 2003;Resnick et al., 2003;Raz et al., 2004Raz et al., , 2010Raz and Rodrigue, 2006;Driscoll et al., 2009;Fjell et al., 2009b;Spreng et al., 2010), including the anterior cingulate (ACC), dorsolateral prefrontal (DLPFC) and orbitofrontal (OFC) cortices. Much of our understanding of age differences and age changes in brain structure comes from volumetric studies, which typically show reductions in regional volumes with age, although increased volumes have also been reported (Salat et al., 2002). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Age is associated with reductions in surface area and cortical thickness, particularly in prefrontal regions. There is also evidence of greater thickness in some regions at older ages. Non-linear age effects in some studies suggest that age may continue to impact brain structure in later decades of life, but relatively few studies have examined the impact of age on brain structure within middle-aged to older adults. We investigated age differences in prefrontal surface area and cortical thickness in healthy adults between the ages of 51 and 81 years. Participants received a structural 3-Tesla magnetic resonance imaging scan. Based on a priori hypotheses, primary analyses focused on surface area and cortical thickness in the dorsolateral prefrontal cortex, anterior cingulate cortex, and orbitofrontal cortex. We also performed exploratory vertex-wise analyses of surface area and cortical thickness across the entire cortex. We found that older age was associated with smaller surface area in the dorsolateral prefrontal and orbitofrontal cortices but greater cortical thickness in the dorsolateral prefrontal and anterior cingulate cortices. Vertex-wise analyses revealed smaller surface area in primarily frontal regions at older ages, but no age effects were found for cortical thickness. Results suggest age is associated with reduced surface area but greater cortical thickness in prefrontal regions during later decades of life, and highlight the differential effects age has on regional surface area and cortical thickness.
    Full-text · Article · Jan 2016 · Frontiers in Aging Neuroscience
Show more