Head over heels but I forget why: Disruptive functional connectivity in older adult fallers with mild cognitive impairment

Rachel A Crockett; Chun Liang Hsu; John R Best; Olivier Beauchet; Teresa Liu-Ambrose

doi:10.1016/j.bbr.2019.112104

Head over heels but I forget why: Disruptive functional connectivity in older adult fallers with mild cognitive impairment

Behav Brain Res. 2019 Dec 30:376:112104. doi: 10.1016/j.bbr.2019.112104. Epub 2019 Jul 17.

Authors

Rachel A Crockett¹, Chun Liang Hsu¹, John R Best¹, Olivier Beauchet², Teresa Liu-Ambrose³

Affiliations

¹ Aging, Mobility, and Cognitive Neuroscience Laboratory, Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
² Faculty of Medicine, McGill University, Montreal, QC, Canada; Centre of Excellence on Aging and Chronic Diseases of McGill University Health Network, Montreal, QC, Canada.
³ Aging, Mobility, and Cognitive Neuroscience Laboratory, Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada. Electronic address: teresa.ambrose@ubc.ca.

PMID: 31325516
DOI: 10.1016/j.bbr.2019.112104

Abstract

Disrupted functional connectivity has been highlighted as a neural mechanism by which impaired cognitive function and mobility co-exist in older adults with mild cognitive impairment (MCI). The objective of this study was to determine the independent and combined effects of MCI and faller status on functional connectivity of three functional networks: default mode network (DMN), fronto-parietal network (FPN) and sensorimotor network (SMN) between 4 groups of older adults: 1) Healthy; 2) MCI without Falls; 3) Fallers without MCI; and 4) Fallers with MCI.

Methods: Sixty-six adults aged 70-80 years old were included. Cognition was assessed using: 1) cognitive dual task; 2) Stroop Colour-Word Test; 3) Trail Making Tests (TMT); and 4) Digit Symbol Substitution Test (DSST). Postural sway was assessed with eyes opened and standing on the floor. Functional connectivity was measured using fMRI while performing a finger-tapping task.

Results: Differences in DMN-SMN connectivity were found for Fallers with MCI vs Fallers without MCI (p = .001). Fallers with MCI had significantly greater postural sway than the other groups. Both DMN-SMN connectivity (p = .03) and postural sway (p = .001) increased in a significantly linear fashion from Fallers without MCI, to MCI without Falls, to Fallers with MCI. Participants with MCI performed significantly worse on the DSST (p = .003) and TMT (p = .007) than those without MCI.

Conclusion: Aberrant DMN-SMN connectivity may underlie reduced postural stability. Having both impaired cognition and mobility is associated with a greater level of disruptive DMN-SMN connectivity and increased postural sway than singular impairment.

Keywords: Aberrant functional connectivity; Falls; Mild cognitive impairment; Postural sway.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Accidental Falls / prevention & control
Aged
Aged, 80 and over
Cognitive Dysfunction / complications
Cognitive Dysfunction / physiopathology*
Cross-Sectional Studies
Feedback, Sensory / physiology*
Female
Humans
Independent Living
Magnetic Resonance Imaging
Male
Neuropsychological Tests
Postural Balance / physiology*