title: Dementia alters standing postural adaptation during a visual search task in older adult men.
abstract: This study investigated the effects of dementia on standing postural adaptation during performance of a visual search task. We recruited 16 older adults with dementia and 15 without dementia. Postural sway was assessed by recording medial-lateral (ML) and anterior-posterior (AP) center-of-pressure when standing with and without a visual search task; i.e., counting target letter frequency within a block of displayed randomized letters. ML sway variability was significantly higher in those with dementia during visual search as compared to those without dementia and compared to both groups during the control condition. AP sway variability was significantly greater in those with dementia as compared to those without dementia, irrespective of task condition. In the ML direction, the absolute and percent change in sway variability between the control condition and visual search (i.e., postural adaptation) was greater in those with dementia as compared to those without. In contrast, postural adaptation to visual search was similar between groups in the AP direction. As compared to those without dementia, those with dementia identified fewer letters on the visual task. In the non-dementia group only, greater increases in postural adaptation in both the ML and AP direction, correlated with lower performance on the visual task. The observed relationship between postural adaptation during the visual search task and visual search task performance--in the non-dementia group only--suggests a critical link between perception and action. Dementia reduces the capacity to perform a visual-based task while standing and thus, appears to disrupt this perception-action synergy.
authors.affiliation: School of Kinesiology, University of Minnesota-Twin Cities, 1900 University Ave SE, Minneapolis, MN 55455, USA.
authors.forename: Azizah J
authors.initials: AJ
authors.lastname: Jor'dan
authors.affiliation: Geriatric Research, Education & Clinical Center, Minneapolis Veterans Affairs Medical Center, 1 Veterans Dr., Minneapolis, MN 55417, USA.
authors.forename: J Riley
authors.initials: JR
authors.lastname: McCarten
authors.affiliation: Geriatric Research, Education & Clinical Center, Minneapolis Veterans Affairs Medical Center, 1 Veterans Dr., Minneapolis, MN 55417, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Rottunda
authors.affiliation: School of Kinesiology, University of Minnesota-Twin Cities, 1900 University Ave SE, Minneapolis, MN 55455, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Stoffregen
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, 1200Center St, Boston, MA 02131, USA.
authors.forename: Brad
authors.initials: B
authors.lastname: Manor
authors.affiliation: School of Kinesiology, University of Minnesota-Twin Cities, 1900 University Ave SE, Minneapolis, MN 55455, USA. Electronic address: mwade@umn.edu.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Wade
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D000369:Aged, 80 and over; D003704:Dementia / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance; D011187:Posture; D011597:Psychomotor Performance; D014796:Visual Perception
keywords: Alzheimer’s disease; Dementia; Dual task; Postural adaptation; Postural sway; Visual search task