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P2.001 Age-related changes of postural responses to vibration of Achilles tendon
S44
Poster Session II
Ageing P2.001 Age-related changes of postural responses to vibration of Achilles tendon D. Abrahamova1° , M. Mancini2 , F. Hlavacka1 , L. Chiari2 Slovakia; 2 Bologna, Italy
1 Bratislava,
Postural responses to altered sensory inputs are important indicators of human balance control. The contribution of the different sensory modalities to balance control is modified by age. Body lean responses to vibrations of Achilles tendon were investigated in order to understand the influence of age and proprioceptive input from lower leg in human stance. Postural responses to bilateral vibrations of Achilles tendon with 10 s duration were recorded at three frequencies 40, 60 and 80 Hz in 8 healthy young (24−27 years) and in 8 healthy older adults (59−70 years). Subjects with eyes closed performed three trials in each of four conditions: stance on firm surface with three frequencies of vibration and stance on foam surface with 60 Hz vibration. Postural responses were characterized by displacement of the pressure center (CoP) and kinematics of body segments motion (3D motion system BTS Smart-e). Body segments tilts in anterior-posterior and medial-lateral directions were measured also by three accelerometers on the head, the upper trunk and the lower trunk level. The results showed that the backward CoP response to bilateral vibration of Achilles tendon increases with age and frequency of vibration. Leg angle response to vibration was found similar in both groups of subjects. Contrary, the slight trunk tilts were induced by vibration in young subjects while in elderly clear backward tilts of the trunk were recorded. The findings showed that the trunk response to proprioreceptive stimulation might be a good indicator of age-related destabilization in balance control. Supported by European grant FP6 SENSACTION-AAL. P2.002 Physical activity and enhanced fitness improve cognitive function in older people without known cognitive impairment, a Cochrane Systematic Review M. Angevaren1° , G. Aufdemkampe1 , H.J.J. Verhaar1 , A. Aleman2 , L. Vanhees1 1 Utrecht, 2 Groningen, The Netherlands Cross sectional studies and RCTs have shown that physical activity, cardiovascular fitness and cognitive function in older individuals are related, suggesting a cardiovascular link between physical activity and cognitive capacity. To assess the effectiveness of physical activity, aimed at improving cardiorespiratory fitness, on cognitive function in healthy people over 55 years of age, the review included RCTs reporting activity, fitness and cognition within the same study design. We searched MEDLINE, EMBASE, PEDro, SPORTDiscus, PsycINFO, CINAHL, Cochrane Controlled Trials Register, Dissertation abstracts international and ongoing trials registers from their beginning to december 2005 with no language restrictions. Eight out of ten studies reported that aerobic exercise interventions resulted in increased cardiorespiratory fitness of the intervention group of approximately 13% and this improvement coincided with improvements in cognitive capacity. The largest effects on cognitive function were found on auditive attention and delayed memory functions (effect sizes of respectively 0.52 and 0.50). Moderate effects were observed for cognitive speed (effect size 0.28) and visual attention (effect size 0.26).
There is strong evidence that aerobic physical activities which improve cardiorespiratory fitness are beneficial for cognitive function in healthy older adults, with effects observed for cognitive speed, delayed memory functions and auditive and visual attention. Clinicians and scientists in the field of neuropsychology should seek mutual agreement upon the use of a smaller battery of cognitive tests. Further research should examine whether psychological and individual factors might account for effects on cognition, or vice versa in clinical trails with long term follow- up.
P2.003 Key processes of executive function underlying dual-tasking M.C. Ashe° , L. Nagamatsu, L.A. Katarynych, T. Liu-Ambrose Vancouver, BC, Canada Background: Impaired dual-tasking is predictive of falls in older adults. The ability to dual-task is dependent on executive functions. Very little research has examined which component of executive functioning is most predictive of dual-tasking ability in older adults. Therefore, the aim of this cross-sectional study was to ascertain which component of executive functioning independently contributed to older women’s performance on the Walk While Talking (WWT) task. Method: A cross-sectional analysis of 137 community-dwelling women with Folstein’s Mini Mental State Examination scores of >24. We assessed dual-taking ability by a complex version of the WWT task. Participants walked a 12 meter course while reciting alternate letters of the alphabet. Time for completion was recorded. We assessed three key central executive functions: (1) set shifting by the Trail Making B Test; (2) updating by the verbal digits backward test; and (3) response inhibition by the Stroop Colour-Word Test. A hierarchical regression model was constructed to determine the independent contribution of these three executive functions to complex WWT task time, after accounting for age, functional mobility, and global cognition. Results: Age, functional mobility, and global cognition together accounted for 25.8% of the variance. Of the three key executive functions, only response inhibition was independently associated with complex WWT task time. Response inhibition accounted for an additional 4% and significantly improved the model (P = 0.04). The total variance accounted by the final model was 30.6%; significant contributors were mobility and response inhibition. Conclusions: Response inhibition is independently associated with dualtasking ability in older women.
P2.004 Can methylphenidate reduce fall risk in community living older adults? RCT for gait & fall risk relations on executive function R. Ben-Itzhak° , N. Giladi, L. Gruendlinger, J.M. Hausdorff Tel-Aviv, Israel; Boston, MA, USA Objectives: Among older adults, falls are a major health concern. A decrease in executive function (EF), common with aging, has been associated with gait instability, reduced mobility and other markers of fall risk. It is not known whether augmenting EF affects gait and fall risk. We tested the hypothesis that methylphenidate reduces fall risk in older adults. Design: Randomized, double-blind, placebo-controlled, single dose crossover study. Setting: Outpatient movement disorders clinic.
Poster Session II
Ageing P2.001 Age-related changes of postural responses to vibration of Achilles tendon D. Abrahamova1° , M. Mancini2 , F. Hlavacka1 , L. Chiari2 Slovakia; 2 Bologna, Italy
1 Bratislava,
Postural responses to altered sensory inputs are important indicators of human balance control. The contribution of the different sensory modalities to balance control is modified by age. Body lean responses to vibrations of Achilles tendon were investigated in order to understand the influence of age and proprioceptive input from lower leg in human stance. Postural responses to bilateral vibrations of Achilles tendon with 10 s duration were recorded at three frequencies 40, 60 and 80 Hz in 8 healthy young (24−27 years) and in 8 healthy older adults (59−70 years). Subjects with eyes closed performed three trials in each of four conditions: stance on firm surface with three frequencies of vibration and stance on foam surface with 60 Hz vibration. Postural responses were characterized by displacement of the pressure center (CoP) and kinematics of body segments motion (3D motion system BTS Smart-e). Body segments tilts in anterior-posterior and medial-lateral directions were measured also by three accelerometers on the head, the upper trunk and the lower trunk level. The results showed that the backward CoP response to bilateral vibration of Achilles tendon increases with age and frequency of vibration. Leg angle response to vibration was found similar in both groups of subjects. Contrary, the slight trunk tilts were induced by vibration in young subjects while in elderly clear backward tilts of the trunk were recorded. The findings showed that the trunk response to proprioreceptive stimulation might be a good indicator of age-related destabilization in balance control. Supported by European grant FP6 SENSACTION-AAL. P2.002 Physical activity and enhanced fitness improve cognitive function in older people without known cognitive impairment, a Cochrane Systematic Review M. Angevaren1° , G. Aufdemkampe1 , H.J.J. Verhaar1 , A. Aleman2 , L. Vanhees1 1 Utrecht, 2 Groningen, The Netherlands Cross sectional studies and RCTs have shown that physical activity, cardiovascular fitness and cognitive function in older individuals are related, suggesting a cardiovascular link between physical activity and cognitive capacity. To assess the effectiveness of physical activity, aimed at improving cardiorespiratory fitness, on cognitive function in healthy people over 55 years of age, the review included RCTs reporting activity, fitness and cognition within the same study design. We searched MEDLINE, EMBASE, PEDro, SPORTDiscus, PsycINFO, CINAHL, Cochrane Controlled Trials Register, Dissertation abstracts international and ongoing trials registers from their beginning to december 2005 with no language restrictions. Eight out of ten studies reported that aerobic exercise interventions resulted in increased cardiorespiratory fitness of the intervention group of approximately 13% and this improvement coincided with improvements in cognitive capacity. The largest effects on cognitive function were found on auditive attention and delayed memory functions (effect sizes of respectively 0.52 and 0.50). Moderate effects were observed for cognitive speed (effect size 0.28) and visual attention (effect size 0.26).
There is strong evidence that aerobic physical activities which improve cardiorespiratory fitness are beneficial for cognitive function in healthy older adults, with effects observed for cognitive speed, delayed memory functions and auditive and visual attention. Clinicians and scientists in the field of neuropsychology should seek mutual agreement upon the use of a smaller battery of cognitive tests. Further research should examine whether psychological and individual factors might account for effects on cognition, or vice versa in clinical trails with long term follow- up.
P2.003 Key processes of executive function underlying dual-tasking M.C. Ashe° , L. Nagamatsu, L.A. Katarynych, T. Liu-Ambrose Vancouver, BC, Canada Background: Impaired dual-tasking is predictive of falls in older adults. The ability to dual-task is dependent on executive functions. Very little research has examined which component of executive functioning is most predictive of dual-tasking ability in older adults. Therefore, the aim of this cross-sectional study was to ascertain which component of executive functioning independently contributed to older women’s performance on the Walk While Talking (WWT) task. Method: A cross-sectional analysis of 137 community-dwelling women with Folstein’s Mini Mental State Examination scores of >24. We assessed dual-taking ability by a complex version of the WWT task. Participants walked a 12 meter course while reciting alternate letters of the alphabet. Time for completion was recorded. We assessed three key central executive functions: (1) set shifting by the Trail Making B Test; (2) updating by the verbal digits backward test; and (3) response inhibition by the Stroop Colour-Word Test. A hierarchical regression model was constructed to determine the independent contribution of these three executive functions to complex WWT task time, after accounting for age, functional mobility, and global cognition. Results: Age, functional mobility, and global cognition together accounted for 25.8% of the variance. Of the three key executive functions, only response inhibition was independently associated with complex WWT task time. Response inhibition accounted for an additional 4% and significantly improved the model (P = 0.04). The total variance accounted by the final model was 30.6%; significant contributors were mobility and response inhibition. Conclusions: Response inhibition is independently associated with dualtasking ability in older women.
P2.004 Can methylphenidate reduce fall risk in community living older adults? RCT for gait & fall risk relations on executive function R. Ben-Itzhak° , N. Giladi, L. Gruendlinger, J.M. Hausdorff Tel-Aviv, Israel; Boston, MA, USA Objectives: Among older adults, falls are a major health concern. A decrease in executive function (EF), common with aging, has been associated with gait instability, reduced mobility and other markers of fall risk. It is not known whether augmenting EF affects gait and fall risk. We tested the hypothesis that methylphenidate reduces fall risk in older adults. Design: Randomized, double-blind, placebo-controlled, single dose crossover study. Setting: Outpatient movement disorders clinic.