title: Cerebrovascular function associated with fluid, not crystallized, abilities in older adults: A transcranial Doppler study.
abstract: The brain is dependent on the cerebrovascular system, particularly microvasculature, for a consistent blood supply; however, age-related changes in this system affect neuronal and therefore cognitive function. Structural vascular markers and vascular disease appear to preferentially affect fluid cognitive abilities, sparing crystallized abilities. We sought to investigate the relationships between cerebrovascular function and cognitive domains. Fifty individuals between 60 and 75 years of age (31 women, 19 men) underwent cognitive testing: Wechsler Vocabulary and Matrix Reasoning subtests (crystallized and fluid ability measures, respectively Wechsler, 2011), and the Addenbrooke's Cognitive Examination-Revised (ACE-R; general cognitive ability; Mioshi, Dawson, Mitchell, Arnold, & Hodges, 2006). Transcranial Doppler (TCD) measures were also collected at rest and during a cognitive word-generation task, from which a lateralization index was calculated. Lower pulsatility index at rest, and greater left lateralization during the TCD cognitive task were associated with better performance on the Matrix Reasoning but not the Vocabulary test; these effects were independent from each other and from any vascular comorbidity burden. These functional findings confirm previous structural studies, which revealed that fluid abilities are more vulnerable to cerebrovascular dysfunction than crystallized abilities, and identify two (likely related) mechanisms: degraded cerebrovascular integrity (indexed by pulsatility index) and a delateralization of function. Cerebrovascular dysfunction is a key contributor to cognitive aging that deserves further attention, particularly in relation to early diagnostic markers of impairment and monitoring of vascular (e.g., physical activity) interventions.
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Hannah A D
authors.initials: HA
authors.lastname: Keage
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Kurylowicz
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Louise M
authors.initials: LM
authors.lastname: Lavrencic
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Owen F
authors.initials: OF
authors.lastname: Churches
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Atlanta
authors.initials: A
authors.lastname: Flitton
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Jessica
authors.initials: J
authors.lastname: Hofmann
authors.affiliation: Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, University of South Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Kohler
authors.affiliation: ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Macquarie University.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Badcock
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology; D017585:Ultrasonography, Doppler, Transcranial; D014825:Vocabulary