Are impairments in visual-spatial attention a critical factor for increased falls risk in seniors? An event-related potential study

Abstract

Falls are experienced annually by approximately one third of community dwellers over the age of 65, and while neuro-cognitive deficits have been shown to increase falls risk, the specific nature of these deficits remain unspecified. Here we examined whether visual-spatial attention may be a core neuro-cognitive system showing abnormal function in fallers. Using a between-groups design, we recorded event-related potentials in a canonical spatial cuing task performed by two groups of senior (aged 65+ years old) participants: those with a recent history of falls and those with no such history. In terms of attentional control systems in cortex, we found no significant differences in function between groups. However, in terms of attentional facilitation of cortical processing, we found that fallers manifest specific abnormalities in the sensory/perceptual processing of targets in the left visual field. Our findings thus suggest that fallers have specific deficits in visuocortical systems associated with attentional enhancement of events on the left side of visual space.

Altered visual–spatial attention to task-irrelevant information is associated with falls risk in older adults

“…Our primary result regarding the relationship between falls risk and attentional facilitation corroborates and extends our previous finding that older adults with a history of falls have altered visual-spatial attention to the left hemifield (Nagamatsu et al, 2009). Based on the notion that the right hemisphere is exclusively responsible for orienting attention to the left side of visual space (e.g., Mangun et al, 1994), this pattern of results is consistent with what is observed in patients with left visual neglect following right hemisphere damage (e.g., Bublak, Redel, & Finke, 2006;Reuter-Lorenz, Kinsbourne, & Moscovitch, 1990).…”

“…We previously found that older adults with a history of falls exhibited reduced attentional facilitation during an orienting task -but that this effect was specific to the left visual field (Nagamatsu et al, 2009). Given the contralateral nature of visual processing, impaired visual-spatial attention exclusively on the left side of visual space is indicative of problems with function and/or structure of the right hemisphere.…”

“…One executive function that is essential for successful navigation through the environment is visual-spatial attention (e.g., Albert, Reinitz, Beusmans, & Gopal, 1999). For instance, visual-spatial attention during a volitional orienting task was previously found to be altered in older adults with a history of falls relative to those without such a history (Nagamatsu, Carolan, Liu-Ambrose, & Handy, 2009). Although differences in sensory processing afforded at an attended location -known as attentional facilitaton -were observed between fallers and non-fallers in the above study, it is currently unknown whether similar alterations in visual-spatial attention may exist for the implicit processing of task-irrelevant information.…”

“…Falls risk was determined using the Physiological Profile Assessment (PPA) -a widely used measure that accounts for multiple physiological risk factors for falls (Lord, Menz, & Tiedemann, 2003). Based on our previous findings (Liu-Ambrose, Nagamatsu, et al, 2008;Nagamatsu et al, 2009), we hypothesized that falls risk would be associated with reduced attentional processing to peripheral probes, and that this effect would be further characterized by hemispheric asymmetries.…”

Mind-wandering and falls risk in older adults.

“…Furthermore, while we did not anticipate reaction times to be associated with falls (e.g., Nagamatsu et al, 2009), we did hypothesize that falls would be associated with task accuracy -or errors of commission -based on the idea that older adults with a history of falls have poorer response inhibition (Liu-Ambrose et al, 2008; Liu-Ambrose, Katarynych, Ashe, Nagamatsu, & Hsu, 2009;Lord & Fitzpatrick, 2001;McGough et al, 2011).…”