title: Differences in dual-task performance and prefrontal cortex activation between younger and older adults.
abstract: BACKGROUND
  The purpose of this study was to examine task-related changes in prefrontal cortex (PFC) activity during a dual-task in both healthy young and older adults and compare patterns of activation between the age groups. We also sought to determine whether brain activation during a dual-task relates to executive/attentional function and how measured factors associated with both of these functions vary between older and younger adults.
  
  
  RESULTS
  Thirty-five healthy volunteers (20 young and 15 elderly) participated in this study. Near-infrared spectroscopy (NIRS) was employed to measure PFC activation during a single-task (performing calculations or stepping) and dual-task (performing both single-tasks at once). Cognitive function was assessed in the older patients with the Trail-making test part B (TMT-B). Major outcomes were task performance, brain activation during task (oxygenated haemoglobin: Oxy-Hb) measured by NIRS, and TMT-B score. Mixed ANOVAs were used to compare task factors and age groups in task performance. Mixed ANOVAs also compared task factors, age group and time factors in task-induced changes in measured Oxy-Hb. Among the older participants, correlations between the TMT-B score and Oxy-Hb values measured in each single-task and in the dual-task were examined using a Pearson correlation coefficient.Oxy-Hb values were significantly increased in both the calculation task and the dual-task within patients in both age groups. However, the Oxy-Hb values associated with there were higher in the older group during the post-task period for the dual-task. Also, there were significant negative correlations between both task-performance accuracy and Oxy-Hb values during the dual-task and participant TMT-B scores.
  
  
  CONCLUSIONS
  Older adults demonstrated age-specific PFC activation in response to dual-task challenge. There was also a significant negative correlation between PFC activation during dual-task and executive/attentional function. These findings suggest that the high cognitive load induced by dual-task activity generates increased PFC activity in older adults. However, this relationship appeared to be strongest in participants with better baseline attention and executive functions.
authors: Graduate School of Health Sciences, Seirei Christopher University, Hamamatsu-City, Shizuoka 433-8558, Japan. hironori.o.10.30@gmail.com
authors: Hironori
authors: H
authors: Ohsugi
authors: Shohei
authors: S
authors: Ohgi
authors: Kenta
authors: K
authors: Shigemori
authors: Eric B
authors: EB
authors: Schneider
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000704:Analysis of Variance; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008433:Mathematics; D010108:Oxyhemoglobins / Q000378:metabolism; D017397:Prefrontal Cortex / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology; D019265:Spectroscopy, Near-Infrared; D013223:Statistics as Topic; D014145:Trail Making Test; D055815:Young Adult
chemical_list: D010108:Oxyhemoglobins