Disruptions in Brain Networks of Older Fallers Are Associated with Subsequent Cognitive Decline: A 12-Month Prospective Exploratory Study

Abstract

Cognitive impairment and impaired mobility are major public health concerns. There is growing recognition that impaired mobility is an early biomarker of cognitive impairment and dementia. The neural basis for this association is currently unclear. We propose disrupted functional connectivity as a potential mechanism. In this 12-month prospective exploratory study, we compared functional connectivity of four brain networks– the default mode network (DMN), fronto-executive network (FEN), fronto-parietal network (FPN), and the primary motor sensory network (SMN) – between community-dwelling older adults with ≥ two falls in the last 12 months and their non-falling counterparts (≤ one fall in the last 12 months). Functional connectivity was examined both at rest and during a simple motor tapping task. Compared with non-fallers, fallers showed more connectivity between the DMN and FPN during right finger tapping (p = 0.04), and significantly less functional connectivity between the SMN and FPN during rest (p≤0.05). Less connectivity between the SMN and FPN during rest was significantly associated with greater decline in both cognitive function and mobility over the12-month period (r = −0.32 and 0.33 respectively; p≤0.04). Thus, a recent history of multiple falls among older adults without a diagnosis of dementia may indicate sub-clinical changes in brain function and increased risk for subsequent decline.

Risco de quedas em idosos residentes na comunidade: revisão sistemática da literatura

“…The articles are from 15 different countries, but especially from the United States of America (18)(19)(24)(25)30,33,39,(53)(54)(55)(56)(57)(58)(59)(60)(61) and Australia (17,28,32,34,36,42,44,(46)(47)52,(62)(63)(64) , with 16 and 13 studies, respectively. The other countries with most articles were Canada (23,29,40,(65)(66)(67)(68) with seven, Netherlands (20,31,35,51,69) with five, and United Kingdom (48,(70)(71)(72) with four. Then came China (26,50,73) , France (45,49,…”

“…Age ≥ 65 years (50,61,63,73,74,77) 6 √ History of falls (28,50,53,57,63,67,69) 7 √ Living alone (63) 1 √ Lower limb prosthesis 0 √ Use of assistive devices (e.g. walker, cane, wheelchair) (17,41) 2 √ Female (20,38,40,59,63,73,74,77) 8…”

“…Change in cognitive function (29,(31)(32)46,48,55,67,76) 8 √ Diminished executive functions (29,49,53) 3…”

Structural neural correlates of impaired mobility and subsequent decline in executive functions: a 12-month prospective study

“…In terms of brain function, our own work demonstrated that compared with their non-faller counterparts, older adults with a history of multiple falls (i.e., ≥ 2 non-syncope falls in the previous 12 months) showed aberrant neural network functional connectivity -a measure of synchronous brain activity (Hsu et al 2014). Notably, the aberrant network connectivity demonstrated by fallers was independently associated with greater decline in both executive functions and mobility over a 12-month period after accounting for relevant covariates (Hsu et al 2014).…”

“…Consistent with these links between mobility and cognition, evidence from neuroimaging studies suggests that slower gait speed or a history of falls is associated with subclinical alterations in both brain structure and function (Rosano et al 2008;Hsu et al 2014;. With respect to structure, in a cross-sectional study of 220 community-dwelling older adults, Rosano and colleagues (Rosano et al 2008) demonstrated that lower gray matter volume in the sensorimotor regions and frontoparietal regions were associated with impaired gait (i.e., shorter steps and longer double support times).…”