Impact of subcortical hyperintensities on dual-tasking in Alzheimer disease and aging

Alzheimer Dis Assoc Disord. Jan-Mar 2012;26(1):28-35. doi: 10.1097/WAD.0b013e3182172c58.

Abstract

Subcortical hyperintensities (SHs) on brain magnetic resonance imaging are associated with cognitive and gait impairment in elderly but their impact on dual-tasking (performing cognitive tasks while walking) in patients with Alzheimer disease (AD) is unknown. This study explored the costs of dual-tasking in relation to SH severity in AD and normal controls (NCs). Cadence while walking on a treadmill, and speed-accuracy-tradeoff (SAT), on 3 working memory tasks, were measured during single-task and dual-task conditions. Dual-task costs (DTC) on SAT, cadence, and overall DTC were measured for each of these tasks. On visual rating of SH severity, AD and NC groups were subdivided into high-SH and low-SH subgroups. Compared with the NC, the AD group performed poorly on all working memory tasks across both conditions, decreased cadence on dual-tasking, and showed a decrement in overall DTC (all P<0.01). When grouped according to SH severity, the low-SH-NC group performed superiorly on working memory tasks (P<0.001) and the high-SH-AD group (P=0.001) showed a decrease in dual-task costs of cadence. Although the AD group showed a decrement in overall DTC (P<0.01) compared with NC, when assessed in terms of SH severity, the high-SH-AD group showed the largest decrement in DTC (P<0.01). Greater SH severity is associated with a decrement in overall dual-tasking ability in AD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging / physiology*
  • Alzheimer Disease / pathology
  • Alzheimer Disease / physiopathology*
  • Brain / pathology
  • Cognition / physiology
  • Gait / physiology*
  • Humans
  • Magnetic Resonance Imaging
  • Memory / physiology*
  • Memory, Short-Term / physiology
  • Middle Aged
  • Neuropsychological Tests
  • Task Performance and Analysis
  • Walking / physiology*