title: Normal aging increases postural preparation errors: Evidence from a two-choice response task with balance constraints.
abstract: Correlational studies indicate an association between age-related decline in balance and cognitive control, but these functions are rarely addressed within a single task. In this study, we investigate adult age differences in a two-choice response task with balance constraints under three levels of response conflict. Sixteen healthy young (20-30 years) and 16 healthy older adult participants (59-74 years) were cued symbolically (letter L vs. R) to lift either the left or the right foot from the floor in a standing position. Response conflict was manipulated by task-irrelevant visual stimuli showing congruent, incongruent, or no foot lift movement. Preparatory weight shifts (PWS) and foot lift movements were recorded using force plates and optical motion capture. Older adults showed longer response times (foot lift) and more PWS errors than younger adults. Incongruent distractors interfered with performance (greater response time and PWS errors), but this compatibility effect did not reliably differ between age groups. Response time effects of age and compatibility were strongly reduced or absent in trials without PWS errors, and for the onset of the first (erroneous) PWS in trials with preparation error. In addition, in older adults only, compatibility effects in the foot lift task correlated significantly with compatibility effects in the Flanker task. The present results strongly suggest that adult age differences in response latencies in a task with balance constraints are related to age-associated increases in postural preparation errors rather than being an epiphenomenon of general slowing.
authors.affiliation: Department of Lifespan Psychology, Max Planck Institute for Human Development,Berlin, Germany. Electronic address: verrel@mpib-berlin.mpg.de.
authors.forename: Julius
authors.initials: J
authors.lastname: Verrel
authors.affiliation: Department of Lifespan Psychology, Max Planck Institute for Human Development,Berlin, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Lisofsky
authors.affiliation: Department of Lifespan Psychology, Max Planck Institute for Human Development,Berlin, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Kühn
authors.affiliation: Department of Lifespan Psychology, Max Planck Institute for Human Development,Berlin, Germany.
authors.forename: Ulman
authors.initials: U
authors.lastname: Lindenberger
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Balance; Inhibition; Partial errors; Response conflict