title: Intraindividual Stepping Reaction Time Variability Predicts Falls in Older Adults With Mild Cognitive Impairment.
abstract: BACKGROUND
  Reaction time measures have considerable potential to aid neuropsychological assessment in a variety of health care settings. One such measure, the intraindividual reaction time variability (IIV), is of particular interest as it is thought to reflect neurobiological disturbance. IIV is associated with a variety of age-related neurological disorders, as well as gait impairment and future falls in older adults. However, although persons diagnosed with Mild Cognitive Impairment (MCI) are at high risk of falling, the association between IIV and prospective falls is unknown.
  
  
  METHODS
  We conducted a longitudinal cohort study in cognitively intact (n = 271) and MCI (n = 154) community-dwelling adults aged 70-90 years. IIV was assessed through a variety of measures including simple and choice hand reaction time and choice stepping reaction time tasks (CSRT), the latter administered as a single task and also with a secondary working memory task.
  
  
  RESULTS
  Logistic regression did not show an association between IIV on the hand-held tasks and falls. Greater IIV in both CSRT tasks, however, did significantly increase the risk of future falls. This effect was specific to the MCI group, with a stronger effect in persons exhibiting gait, posture, or physiological impairment.
  
  
  CONCLUSIONS
  The findings suggest that increased stepping IIV may indicate compromised neural circuitry involved in executive function, gait, and posture in persons with MCI increasing their risk of falling. IIV measures have potential to assess neurobiological disturbance underlying physical and cognitive dysfunction in old age, and aid fall risk assessment and routine care in community and health care settings.
authors: School of Psychology, University of Leeds, UK.|Centre for Health Brain Ageing (CHeBA), School of Psychiatry and.
authors: David
authors: D
authors: Bunce
authors: School of Psychology, University of Leeds, UK.
authors: Becky I
authors: BI
authors: Haynes
authors: Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
authors: Stephen R
authors: SR
authors: Lord
authors: Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
authors: Yves J
authors: YJ
authors: Gschwind
authors: Centre for Health Brain Ageing (CHeBA), School of Psychiatry and.|Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, New South Wales, Australia.
authors: Nicole A
authors: NA
authors: Kochan
authors: Centre for Health Brain Ageing (CHeBA), School of Psychiatry and.|Department of Developmental Disability Neuropsychiatry and.
authors: Simone
authors: S
authors: Reppermund
authors: Centre for Health Brain Ageing (CHeBA), School of Psychiatry and.|Dementia Collaborative Research Centre-Assessment and Better Care, School of Psychiatry, University of New South Wales, Sydney, Australia.|Academic Department for Old Age Psychiatry, Prince of Wales Hospital, Sydney, New South Wales, Australia.
authors: Henry
authors: H
authors: Brodaty
authors: Centre for Health Brain Ageing (CHeBA), School of Psychiatry and.|Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, New South Wales, Australia.
authors: Perminder S
authors: PS
authors: Sachdev
authors: Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
authors: Kim
authors: K
authors: Delbaere
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data; D000368:Aged; D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D015331:Cohort Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D011187:Posture / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D018570:Risk Assessment
keywords: Falls; Intraindividual variability; Mild cognitive impairment; Reaction time