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Faster cognitive decline in the years prior to MR imaging is associated with smaller hippocampal volumes in cognitively healthy older persons.

Fleischman DA, Yu L, Arfanakis K, Han SD, Barnes LL, Arvanitakis Z, Boyle PA, Bennett DA - Front Aging Neurosci (2013)

Bottom Line: Results showed that there was significant variability in the trajectories of cognitive change prior to imaging and that faster cognitive decline was associated with smaller hippocampal volumes.Domain-specific analyses suggested that this association was primarily driven by decline in working memory.The results emphasize the importance of closely examining cognitive change and its association with brain structure during the years in which older persons are considered cognitively healthy.

View Article: PubMed Central - PubMed

Affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center Chicago, IL, USA ; Department of Neurological Sciences, Rush University Medical Center Chicago, IL, USA ; Department of Behavioral Sciences, Rush University Medical Center Chicago, IL, USA.

ABSTRACT
Early identification of persons at risk for cognitive decline in aging is critical to optimizing treatment to delay or avoid a clinical diagnosis of mild cognitive impairment (MCI) or dementia due to Alzheimer's disease (AD). To accomplish early identification, it is essential that trajectories of cognitive change be characterized and associations with established biomarkers of MCI and AD be examined during the phase in which older persons are considered cognitively healthy. Here we examined the association of rate of cognitive decline in the years leading up to structural magnetic resonance imaging with an established biomarker, hippocampal volume. The sample comprised 211 participants of the Rush Memory and Aging Project who had an average of 5.5 years of cognitive data prior to structural scanning. Results showed that there was significant variability in the trajectories of cognitive change prior to imaging and that faster cognitive decline was associated with smaller hippocampal volumes. Domain-specific analyses suggested that this association was primarily driven by decline in working memory. The results emphasize the importance of closely examining cognitive change and its association with brain structure during the years in which older persons are considered cognitively healthy.

No MeSH data available.


Related in: MedlinePlus

Distribution of person-specific pre-scan rates of decline.
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Figure 2: Distribution of person-specific pre-scan rates of decline.

Mentions: To examine the association of pre-scan rate of change in cognitive function with hippocampal volume, we first constructed a linear mixed-effects model with a term for time (since baseline in years) to estimate each person's annual rate of global cognitive change (i.e., slope), adjusted for age, sex, and education. On average there was no overall decline in global cognition (Estimate = −0.004, SE = 0.004, p = 0.273). However, since some persons declined, others remained the same, and still others improved as a result of practice and learning, the variance estimate for person-specific slopes was highly significant (Estimate = 0.0007, SE = 0.0002, p < 0.001). Figure 1 illustrates the predicted linear decline in global cognition for a randomly-selected sample of 20 persons. Figure 2 further illustrates the distribution of person-specific pre-scan rates of decline (Mean = −0.005, SD = 0.019, range = −0.057 to 0.039). As shown by these figures, even among these cognitively healthy persons, there is a sizeable amount of variability in the rates of decline: some persons declined faster, some slower, while other persons improved slightly.


Faster cognitive decline in the years prior to MR imaging is associated with smaller hippocampal volumes in cognitively healthy older persons.

Fleischman DA, Yu L, Arfanakis K, Han SD, Barnes LL, Arvanitakis Z, Boyle PA, Bennett DA - Front Aging Neurosci (2013)

Distribution of person-specific pre-scan rates of decline.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672675&req=5

Figure 2: Distribution of person-specific pre-scan rates of decline.
Mentions: To examine the association of pre-scan rate of change in cognitive function with hippocampal volume, we first constructed a linear mixed-effects model with a term for time (since baseline in years) to estimate each person's annual rate of global cognitive change (i.e., slope), adjusted for age, sex, and education. On average there was no overall decline in global cognition (Estimate = −0.004, SE = 0.004, p = 0.273). However, since some persons declined, others remained the same, and still others improved as a result of practice and learning, the variance estimate for person-specific slopes was highly significant (Estimate = 0.0007, SE = 0.0002, p < 0.001). Figure 1 illustrates the predicted linear decline in global cognition for a randomly-selected sample of 20 persons. Figure 2 further illustrates the distribution of person-specific pre-scan rates of decline (Mean = −0.005, SD = 0.019, range = −0.057 to 0.039). As shown by these figures, even among these cognitively healthy persons, there is a sizeable amount of variability in the rates of decline: some persons declined faster, some slower, while other persons improved slightly.

Bottom Line: Results showed that there was significant variability in the trajectories of cognitive change prior to imaging and that faster cognitive decline was associated with smaller hippocampal volumes.Domain-specific analyses suggested that this association was primarily driven by decline in working memory.The results emphasize the importance of closely examining cognitive change and its association with brain structure during the years in which older persons are considered cognitively healthy.

View Article: PubMed Central - PubMed

Affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center Chicago, IL, USA ; Department of Neurological Sciences, Rush University Medical Center Chicago, IL, USA ; Department of Behavioral Sciences, Rush University Medical Center Chicago, IL, USA.

ABSTRACT
Early identification of persons at risk for cognitive decline in aging is critical to optimizing treatment to delay or avoid a clinical diagnosis of mild cognitive impairment (MCI) or dementia due to Alzheimer's disease (AD). To accomplish early identification, it is essential that trajectories of cognitive change be characterized and associations with established biomarkers of MCI and AD be examined during the phase in which older persons are considered cognitively healthy. Here we examined the association of rate of cognitive decline in the years leading up to structural magnetic resonance imaging with an established biomarker, hippocampal volume. The sample comprised 211 participants of the Rush Memory and Aging Project who had an average of 5.5 years of cognitive data prior to structural scanning. Results showed that there was significant variability in the trajectories of cognitive change prior to imaging and that faster cognitive decline was associated with smaller hippocampal volumes. Domain-specific analyses suggested that this association was primarily driven by decline in working memory. The results emphasize the importance of closely examining cognitive change and its association with brain structure during the years in which older persons are considered cognitively healthy.

No MeSH data available.


Related in: MedlinePlus