Poster 11 Characteristics of Hand Force Production for Lifting of an Object in Dementia Patients

Abstract

Ability to produce lifting force appropriately tuned for weight of daily objects using visual information may decline with dementia. To investigate this, force generated during lifting of plastic bottles with/and without visual information of water volume was compared between elderly individuals with and without dementia. Matched-pairs control group. Welfare institution for elderly people. Ten elderly patients with dementia (72-86 yrs., CDR ≥ 1, MMSE ≤ 20, FAB ≤ 15), and 10 age-matched elderly controls (77-89 yrs., CDR ≤ 0.5, MMSE ≥ 27, FAB ≥ 10). Not applicable. The participants lifted small transparent or opaque (black) plastic tea bottles (230 mm height, 65 mm diameter) weighing 100 and 500 g repetitively from a force-transducer-equipped platform providing continuous lifting force information. Tests were performed under constant-weight and switching-weight conditions. Duration between lifting force increase and the bottle lift-off moment, average and peak lifting force rate, and their trial-to-trail variability were evaluated. No dementia-control difference was found in any of the parameters examined for the constant-weight conditions. For the condition of switching weights with the transparent bottle, on the other hand, there was a significant group difference in the duration and force-rate parameters. The dementia participants were clearly less sufficient in production of predictive lifting force using a visual cue of object weight. Cognitive decline with dementia does not affect lifting force production in a steady weight condition. It, however, affects visual-volume cue based adjustment of lifting force production.