White matter hyperintensities and impaired choice stepping reaction time in older people.
White matter hyperintensities (WMHs) are associated with impaired mobility in older people, but no studies have identified neuropsychological and sensorimotor mediating factors for this association. Our objective was to determine whether neuropsychological and sensorimotor functions mediate the association of WMHs and choice stepping reaction time (CSRT) under standard and dual-task conditions using structural equation modeling. Two hundred fifty-four older community dwellers (77.8 ± 4.5 years) underwent structural magnetic resonance imaging, CSRT tests, neuropsychological and sensorimotor assessments. WMH volumes were quantified using an automated method. WMH volumes were significantly associated with neuropsychological tests and dual task CSRT performance. All neuropsychological and sensorimotor variables were also significantly associated with standard and dual task CSRT. The structural equation modeling revealed that impaired sensorimotor function was the only factor influencing impaired stepping performances in the standard condition. In the dual task condition, the association between WMHs and CSRT was mediated through slowed cognitive processing and not through reduced sensorimotor functioning. The conclusion was that WMHs are associated with slowed performance on a dual task CSRT task and this relationship is explained primarily by underlying neuropsychological impairments.
Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
Jacqueline J
JJ
Zheng
Kim
K
Delbaere
Jacqueline C T
JC
Close
Perminder S
PS
Sachdev
Wei
W
Wen
Stephen R
SR
Lord
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000502:physiology* / Q000523:psychology; D002755:Choice Behavior / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*