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P3‐266: Cardiorespiratory Fitness is Associated with Hippocampal Volume and Episodic Memory in a Population at Risk for Alzheimer’S Disease
Author(s) -
Dougherty Ryan J.,
Schultz Stephanie A.,
Boots Elizabeth A.,
Johnson Sterling C.,
Edwards Dorothy Farrar,
Okonkwo Ozioma C.,
Cook Dane B.
Publication year - 2016
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2016.06.1929
Subject(s) - cardiorespiratory fitness , episodic memory , medicine , alzheimer's disease , dementia , population , hippocampal formation , cognitive decline , cohort , atrophy , psychology , brain size , disease , gerontology , audiology , magnetic resonance imaging , cognition , psychiatry , environmental health , radiology
Background: As the world’s population ages, there is growing concern in neurovascular health and cognition. Executive functioning, such as conflict resolution, is often the first cognitive domain impacted by aging, and may be predictive of future impairment [1]. Although this cognitive decline is well established, less is known about the neurovascular etiology. This study examines differences between younger and older adults using behaviour and functional magnetic resonance imaging (fMRI) activation data ascertained during a flanker executive task. We implemented a multiecho fMRI sequence for increased functional sensitivity and minimal impact of physiological nuisance effects that scale with age and vascular disease. We hypothesized that there would be differential activation patterns between groups and an increase in reaction time in the older adult group. Methods:We recruited 15 non-demented older adults and 16 healthy younger adults from the community (Table 1). Multi-echo fMRI (3T Philips scanner) was performed using a blood-oxygenation level dependent (BOLD) acquisition at 3 echo times (14,35,57 ms), with a repetition time of 2.3 s (duration of 7 min 45 sec). The flanker executive task was administered during the fMRI using E-prime software (V1.2). The multiple echoes from the fMRI time-series were weighted according to Posse et al. [2], and analyses were conducted using FMRIB FEAT software (V5.0.7). Group statistics were run using R software (V3.1.1). Older participants underwent the Montreal Cognitive Assessment (V7.2). Results: Older adults showed greater BOLD % signal changes in the left medial temporal lobe (MTL) when compared to younger adults (P1⁄40.0235, t1⁄42.48) (Figure 1). This increased BOLD activation did not correspond to improved behavioural performance, however, as reaction time was significantly greater in older adults (P<0.0002, t1⁄44.69) (Figure 2). Conclusions:Through multi-echo fMRI, we demonstrated a difference of activation in the brain explained by age. Namely, there was increased BOLD signal in theMTL, an area implicated in cognitive decline in the aging community [1]. Furthermore, although these findings may indicate an fMRI compensatory activation strategy, they did not prove adequate enough to match the performance of younger adults on this executive task. References: 1. Buckner, R. L. (2004). Neuron, 44(1),195-208. 2. Posse, Stefan, et al. (1999). Magnetic Resonance in Medicine, 42(1),87-97.