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

•Older fallers showed lower brain volumes compared with older non-fallers.•Lower white matter volume was associated with executive function decline.•Falls in older adults indicate subclinical alterations in brain volume.•Changes in brain volume are associated with future decline in executive functions.

Impaired mobility, such as falls, may be an early biomarker of subsequent cognitive decline and is associated with subclinical alterations in both brain structure and function. In this 12-month prospective study, we examined whether there are volumetric differences in gray matter and subcortical regions, as well as cerebral white matter, between older fallers and non-fallers. In addition, we assessed whether these baseline volumetric differences are associated with changes in cognitive function over 12 months. A total of 66 community-dwelling older adults were recruited and categorized by their falls status. Magnetic resonance imaging occurred at baseline and participants' physical and cognitive performances were assessed at baseline and 12-months. At baseline, fallers showed significantly lower volumes in gray matter, subcortical regions, and cerebral white matter compared with non-fallers. Notably, fallers had significantly lower left lateral orbitofrontal white matter volume. Moreover, lower left lateral orbitofrontal white matter volume at baseline was associated with greater decline in set-shifting performance over 12 months. Our data suggest that falls may indicate subclinical alterations in regional brain volume that are associated with subsequent decline in executive functions.