Reduction of Dual-task Costs by Noninvasive Modulation of Prefrontal Activity in Healthy Elders.
Dual tasking (e.g., walking or standing while performing a cognitive task) disrupts performance in one or both tasks, and such dual-task costs increase with aging into senescence. Dual tasking activates a network of brain regions including pFC. We therefore hypothesized that facilitation of prefrontal cortical activity via transcranial direct current stimulation (tDCS) would reduce dual-task costs in older adults. Thirty-seven healthy older adults completed two visits during which dual tasking was assessed before and after 20 min of real or sham tDCS targeting the left pFC. Trials of single-task standing, walking, and verbalized serial subtractions were completed, along with dual-task trials of standing or walking while performing serial subtractions. Dual-task costs were calculated as the percent change in markers of gait and postural control and serial subtraction performance, from single to dual tasking. Significant dual-task costs to standing, walking, and serial subtraction performance were observed before tDCS (p < .01). These dual-task costs were less after real tDCS as compared with sham tDCS as well as compared with either pre-tDCS condition (p < .03). Further analyses indicated that tDCS did not alter single task performance but instead improved performance solely within dual-task conditions (p < .02). These results demonstrate that dual tasking can be improved by modulating prefrontal activity, thus indicating that dual-task decrements are modifiable and may not necessarily reflect an obligatory consequence of aging. Moreover, tDCS may ultimately serve as a novel approach to preserving dual-task capacity into senescence.
Hebrew SeniorLife, Boston, MA.|Beth Israel Deaconess Medical Center, Boston, MA.|Harvard Medical School.
Brad
B
Manor
Peking University, Beijing, China.
Junhong
J
Zhou
Hebrew SeniorLife, Boston, MA.|Beth Israel Deaconess Medical Center, Boston, MA.|Harvard Medical School.
Azizah
A
Jor'dan
Peking University, Beijing, China.
Jue
J
Zhang
Peking University, Beijing, China.
Jing
J
Fang
Beth Israel Deaconess Medical Center, Boston, MA.|Harvard Medical School.
Alvaro
A
Pascual-Leone
D000375:Aging / Q000502:physiology* / Q000523:psychology*; D015331:Cohort Studies; D056344:Executive Function / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D008875:Middle Aged; D009483:Neuropsychological Tests; D011187:Posture / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation; D016138:Walking / Q000502:physiology / Q000523:psychology