human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Recent findings suggest that executive function ( EF ) plays a critical role in the regulation of gait in older adults , especially under complex and challenging conditions , and that EF deficits may , therefore , contribute to fall risk . The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up . Secondary objectives were to assess whether single and dual task walking abilities , an alternative window into EF , were associated with fall risk . Methodology /Main Results We longitudinally followed 256 community-living older adults ( age : 76.4±4.5 yrs ; 61 % women ) who were dementia free and had good mobility upon entrance into the study . At baseline , a computerized cognitive battery generated an index of EF , attention , a closely related construct , and other cognitive domains . Gait was assessed during single and dual task conditions . Falls data were collected prospect ively using monthly calendars . Negative binomial regression quantified risk ratios ( RR ) . After adjusting for age , gender and the number of falls in the year prior to the study , only the EF index ( RR : .85 ; CI : .74–.98 , p = .021 ) , the attention index ( RR : .84 ; CI : .75–.94 , p = .002 ) and dual tasking gait variability ( RR : 1.11 ; CI : 1.01–1.23 ; p = .027 ) were associated with future fall risk . Other cognitive function measures were not related to falls . Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up ( p<0.02 ) . Conclusions / Significance These findings demonstrate that among community-living older adults , the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier . The present results link falls among older adults to cognition , indicating that screening EF will likely enhance fall risk assessment , and that treatment of EF may reduce fall risk In developed countries ,  falls  in  older people  represent a rising problem . As effective prevention should start before the risk becomes evident , an early predictor is needed . Single stance instability would appear as a major risk factor . Aims of the study were to describe single stance stability , its sensory components , and their correlation with age and gender . A r and om sample of 597 older adults ( 319 men , 278 women ) living at home , aged 65–84 , was studied . Stability tests were performed with an electronic postural station . The single stance test showed the impairment of single stance stability in older individuals ( 75–84 yrs ) . The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses .  Younger subjects ( 65–74 yrs ) exhibited better , but still inadequate , proprioceptive control with compensatory visual stabilization . Gender differences appeared in older subjects : women were significantly less stable than men . The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident . Adequate proprioceptive control could mitigate the effects of all other risks of falling BACKGROUND Falls occur mainly while walking or performing concurrent tasks . We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk  in elderly individuals . METHODS We conducted a 12-month r and omized controlled trial involving 134 community-dwelling individuals older than 65 years , who are at increased risk of falling . They were r and omly assigned to an intervention group ( n = 66 ) or a delayed intervention control group scheduled to start the program 6 months later ( n = 68 ) . The intervention was a 6-month multitask exercise program performed to the rhythm of piano music .  Change in gait variability under dual-task condition from baseline to 6 months was the primary end point . Secondary outcomes included changes in balance , functional performances , and fall risk . RESULTS At 6 months , there was a reduction in stride length variability ( adjusted mean difference , -1.4 % ; P < .002 ) under dual-task condition in the intervention group , compared with the delayed intervention control group . Balance and functional tests improved compared with the control group . There were fewer falls in the intervention group ( incidence rate ratio , 0.46 ; 95 % confidence interval , 0.27 - 0.79 ) and a lower risk of falling ( relative risk , 0.61 ; 95 % confidence interval , 0.39 - 0.96 ) . Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention . The benefit of the intervention on gait variability persisted 6 months later . CONCLUSION In community-dwelling older people at increased risk of falling , a 6-month music-based multitask exercise program improved gait under dual-task condition , improved balance , and reduced both the rate of falls and the risk of falling . Trial Registration clinical trials.gov Identifier : NCT01107288 OBJECTIVES To define clinical ly relevant cutpoints for usual gait speed and to investigate their predictive value for health-related events in older persons . DESIGN Prospect i ve cohort study . SETTING Health , Aging and Body Composition Study . PARTICIPANTS Three thous and forty-seven well-functioning older persons ( mean age 74.2 ) . MEASUREMENTS Usual gait speed on a 6-m course was assessed at baseline . Participants were r and omly divided into two groups to identify ( Sample A ; n=2,031 ) and then vali date ( Sample B ; n=1,016 ) usual gait-speed cutpoints . Rates of persistent lower extremity limitation events ( mean follow-up 4.9 years ) were calculated according to gait speed in Sample A. A cutpoint ( defining high- ( < 1 m/s ) and low risk ( > or = 1 m/s ) groups ) was identified based on persistent lower extremity limitation events . The predictive value of the identified cutpoints for major health-related events ( persistent severe lower extremity limitation , death , and hospitalization ) was evaluated in Sample B using Cox regression analyses . RESULTS A grade d response was seen between risk groups and health-related outcomes . Participants in the high-risk group had a higher risk of persistent lower extremity limitation ( rate ratio (RR)=2.20 , 95 % confidence interval (CI)=1.76 - 2.74 ) , persistent severe lower extremity limitation ( RR=2.29 , 95 % CI=1.63 - 3.20 ) , death ( RR=1.64 , 95 % CI=1.14 - 2.37 ) , and hospitalization ( RR=1.48 , 95 % CI=1.02 - 2.13 ) than those in the low-risk group . CONCLUSION Usual gait speed of less than 1 m/s identifies persons at high risk of health-related outcomes in well-functioning older people . Provision of a clinical ly meaningful cutpoint for usual gait speed may facilitate its use in clinical and research setting OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity AIM To examine the role of disease-related factors and age-related physiological changes in affecting gait speed and stride length in the elderly . SUBJECTS 925 men and 890 women aged 70 years and above who were ambulant , recruited by r and om sampling stratified according to age and sex , from all recipients of Old Age and Disability Allowance in Hong Kong . DESIGN Gait was assessed by measuring the time taken and the number of steps required to complete a 16-foot walk . Information on health and functional status , cognitive function , and depressive symptoms was collected , and anthropometric indices obtained . Factors affecting walking speed and stride were examined in the overall population and also after excluding those with physical disability or diseases . RESULTS Results were analyzed separately for men and women since mean walking speed was slower in women , who also took a larger number of steps . Age , coexisting disease , leg or back pain , poor vision , low level of physical activity , functional and cognitive impairment , high depressive symptom score , and anthropometric indices were all negatively associated with walking speed . Fallers also had slower speed . After excluding those with diseases or physical impairment , multivariate analysis showed that the only factors affecting speed were age in men , and age , height , and level of physical activity in women . Age and height were factors associated with stride length in men , and height only for women . CONCLUSION Both disease-related factors as well as age-related physiological changes contribute to the decline in walking speed and stride length Objective : To evaluate the effects of a new , individually adjusted , progressive and specific balance group training programme on fear of falling , step execution , and gait in healthy elderly people with fear of falling and tend to fall . Design : R and omized controlled trial . Setting : The study was conducted in Stockholm County , Sweden . Subjects : Fifty-nine community dwelling elderly people were recruited by advertisement , and allocated at r and om to an intervention group ( n = 38 ) or a control group ( n = 21 ) . Intervention : Individually adjusted , progressive and specific balance group training was given three times a week for three months . The training incorporated elements included in , and required for , independent activities of daily living , and for reactions to loss of balance during dual or multiple tasks . Main measures : Fear of falling was assessed with Falls Efficacy Scale International ( FES-I ) . The reaction time of step execution was measured with the step-execution test , and gait was measured with GAITRite ® . Results : After three months the intervention group showed significant positive changes in the FES-I ( P = 0.008 ) , in the step-execution phase of dual-task performance ( P = 0.012 ) , and in gait at preferred speed during single-task performance ; in cadence ( P = 0.030 ) and , at fast speed , in velocity ( P = 0.004 ) and cadence ( P = 0.001 ) . Significant decreases were also found for the likelihood of depression after participating in the training programme . Conclusion : This new balance training programme is feasible and leads to decreased fear of falling , decreased time for step execution during dual-task performance and increased velocity during fast walking OBJECTIVE To determine , in a cohort of ambulatory older adults , whether spatial-temporal measures of foot placement during gait can predict the likelihood of future falls or whether these measures are more likely to be indicative of adaptations associated with pre-existing fear of falling . DESIGN Prospect i ve cohort study . SETTING Baseline gait measurements were performed in a gait and balance laboratory ; subsequent history of falling was monitored prospect ively for 1 year in two self-care facilities . PARTICIPANTS Fourteen male and 61 female consecutive volunteers ( mean age = 82 , SD = 6 ) who were independent in activities of daily living and able to walk 10 m unaided . MEASUREMENTS Spatial gait parameters  were derived from digitized " footprints " ; temporal parameters were derived using footswitches . A clinical activity-based gait assessment was also performed . The dependent variables were pre-existing fear of falling ( reported at baseline ) and future falling ( experiencing one or more falls during the 1-year follow-up ) . MAIN RESULTS Reduced stride length , reduced speed , increased double-support time , and poorer clinical gait scores were associated with fear but showed little evidence of an independent association with falling . Conversely , increased stride-to-stride variability in stride length , speed , and double-support was associated independently with falling but showed little evidence of relationship to fear . Increased stride width showed some evidence of association with both falling and fear . Stride-to-stride variability in speed was the single best independent predictor of falling . CONCLUSIONS Changes in gait cited previously as risk factors for falling , i.e. , decreased stride length and speed and prolonged double support , may in fact be stabilizing adaptations related to fear 
    Output:
    
agent
Gait speed significantly reduced with the addition of a dual task , with increasing complexity showing greater decrements .
Cadence , stride time , and measures of gait variability were all negatively affected under the dual-task condition .
In older adults , the addition of a dual task significantly reduces gait speed and cadence , with possible implication s for the assessment of older people , as the addition of a dual task may expose deficits not observed under single-task assessment
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Recent findings suggest that executive function ( EF ) plays a critical role in the regulation of gait in older adults , especially under complex and challenging conditions , and that EF deficits may , therefore , contribute to fall risk . The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up . Secondary objectives were to assess whether single and dual task walking abilities , an alternative window into EF , were associated with fall risk . Methodology /Main Results We longitudinally followed 256 community-living older adults ( age : 76.4±4.5 yrs ; 61 % women ) who were dementia free and had good mobility upon entrance into the study . At baseline , a computerized cognitive battery generated an index of EF , attention , a closely related construct , and other cognitive domains . Gait was assessed during single and dual task conditions . Falls data were collected prospect ively using monthly calendars . Negative binomial regression quantified risk ratios ( RR ) . After adjusting for age , gender and the number of falls in the year prior to the study , only the EF index ( RR : .85 ; CI : .74–.98 , p = .021 ) , the attention index ( RR : .84 ; CI : .75–.94 , p = .002 ) and dual tasking gait variability ( RR : 1.11 ; CI : 1.01–1.23 ; p = .027 ) were associated with future fall risk . Other cognitive function measures were not related to falls . Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up ( p<0.02 ) . Conclusions / Significance These findings demonstrate that among community-living older adults , the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier . The present results link falls among older adults to cognition , indicating that screening EF will likely enhance fall risk assessment , and that treatment of EF may reduce fall risk In developed countries ,  falls  in  older people  represent a rising problem . As effective prevention should start before the risk becomes evident , an early predictor is needed . Single stance instability would appear as a major risk factor . Aims of the study were to describe single stance stability , its sensory components , and their correlation with age and gender . A r and om sample of 597 older adults ( 319 men , 278 women ) living at home , aged 65–84 , was studied . Stability tests were performed with an electronic postural station . The single stance test showed the impairment of single stance stability in older individuals ( 75–84 yrs ) . The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses .  Younger subjects ( 65–74 yrs ) exhibited better , but still inadequate , proprioceptive control with compensatory visual stabilization . Gender differences appeared in older subjects : women were significantly less stable than men . The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident . Adequate proprioceptive control could mitigate the effects of all other risks of falling BACKGROUND Falls occur mainly while walking or performing concurrent tasks . We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk  in elderly individuals . METHODS We conducted a 12-month r and omized controlled trial involving 134 community-dwelling individuals older than 65 years , who are at increased risk of falling . They were r and omly assigned to an intervention group ( n = 66 ) or a delayed intervention control group scheduled to start the program 6 months later ( n = 68 ) . The intervention was a 6-month multitask exercise program performed to the rhythm of piano music .  Change in gait variability under dual-task condition from baseline to 6 months was the primary end point . Secondary outcomes included changes in balance , functional performances , and fall risk . RESULTS At 6 months , there was a reduction in stride length variability ( adjusted mean difference , -1.4 % ; P < .002 ) under dual-task condition in the intervention group , compared with the delayed intervention control group . Balance and functional tests improved compared with the control group . There were fewer falls in the intervention group ( incidence rate ratio , 0.46 ; 95 % confidence interval , 0.27 - 0.79 ) and a lower risk of falling ( relative risk , 0.61 ; 95 % confidence interval , 0.39 - 0.96 ) . Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention . The benefit of the intervention on gait variability persisted 6 months later . CONCLUSION In community-dwelling older people at increased risk of falling , a 6-month music-based multitask exercise program improved gait under dual-task condition , improved balance , and reduced both the rate of falls and the risk of falling . Trial Registration clinical trials.gov Identifier : NCT01107288 OBJECTIVES To define clinical ly relevant cutpoints for usual gait speed and to investigate their predictive value for health-related events in older persons . DESIGN Prospect i ve cohort study . SETTING Health , Aging and Body Composition Study . PARTICIPANTS Three thous and forty-seven well-functioning older persons ( mean age 74.2 ) . MEASUREMENTS Usual gait speed on a 6-m course was assessed at baseline . Participants were r and omly divided into two groups to identify ( Sample A ; n=2,031 ) and then vali date ( Sample B ; n=1,016 ) usual gait-speed cutpoints . Rates of persistent lower extremity limitation events ( mean follow-up 4.9 years ) were calculated according to gait speed in Sample A. A cutpoint ( defining high- ( < 1 m/s ) and low risk ( > or = 1 m/s ) groups ) was identified based on persistent lower extremity limitation events . The predictive value of the identified cutpoints for major health-related events ( persistent severe lower extremity limitation , death , and hospitalization ) was evaluated in Sample B using Cox regression analyses . RESULTS A grade d response was seen between risk groups and health-related outcomes . Participants in the high-risk group had a higher risk of persistent lower extremity limitation ( rate ratio (RR)=2.20 , 95 % confidence interval (CI)=1.76 - 2.74 ) , persistent severe lower extremity limitation ( RR=2.29 , 95 % CI=1.63 - 3.20 ) , death ( RR=1.64 , 95 % CI=1.14 - 2.37 ) , and hospitalization ( RR=1.48 , 95 % CI=1.02 - 2.13 ) than those in the low-risk group . CONCLUSION Usual gait speed of less than 1 m/s identifies persons at high risk of health-related outcomes in well-functioning older people . Provision of a clinical ly meaningful cutpoint for usual gait speed may facilitate its use in clinical and research setting OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity AIM To examine the role of disease-related factors and age-related physiological changes in affecting gait speed and stride length in the elderly . SUBJECTS 925 men and 890 women aged 70 years and above who were ambulant , recruited by r and om sampling stratified according to age and sex , from all recipients of Old Age and Disability Allowance in Hong Kong . DESIGN Gait was assessed by measuring the time taken and the number of steps required to complete a 16-foot walk . Information on health and functional status , cognitive function , and depressive symptoms was collected , and anthropometric indices obtained . Factors affecting walking speed and stride were examined in the overall population and also after excluding those with physical disability or diseases . RESULTS Results were analyzed separately for men and women since mean walking speed was slower in women , who also took a larger number of steps . Age , coexisting disease , leg or back pain , poor vision , low level of physical activity , functional and cognitive impairment , high depressive symptom score , and anthropometric indices were all negatively associated with walking speed . Fallers also had slower speed . After excluding those with diseases or physical impairment , multivariate analysis showed that the only factors affecting speed were age in men , and age , height , and level of physical activity in women . Age and height were factors associated with stride length in men , and height only for women . CONCLUSION Both disease-related factors as well as age-related physiological changes contribute to the decline in walking speed and stride length Objective : To evaluate the effects of a new , individually adjusted , progressive and specific balance group training programme on fear of falling , step execution , and gait in healthy elderly people with fear of falling and tend to fall . Design : R and omized controlled trial . Setting : The study was conducted in Stockholm County , Sweden . Subjects : Fifty-nine community dwelling elderly people were recruited by advertisement , and allocated at r and om to an intervention group ( n = 38 ) or a control group ( n = 21 ) . Intervention : Individually adjusted , progressive and specific balance group training was given three times a week for three months . The training incorporated elements included in , and required for , independent activities of daily living , and for reactions to loss of balance during dual or multiple tasks . Main measures : Fear of falling was assessed with Falls Efficacy Scale International ( FES-I ) . The reaction time of step execution was measured with the step-execution test , and gait was measured with GAITRite ® . Results : After three months the intervention group showed significant positive changes in the FES-I ( P = 0.008 ) , in the step-execution phase of dual-task performance ( P = 0.012 ) , and in gait at preferred speed during single-task performance ; in cadence ( P = 0.030 ) and , at fast speed , in velocity ( P = 0.004 ) and cadence ( P = 0.001 ) . Significant decreases were also found for the likelihood of depression after participating in the training programme . Conclusion : This new balance training programme is feasible and leads to decreased fear of falling , decreased time for step execution during dual-task performance and increased velocity during fast walking OBJECTIVE To determine , in a cohort of ambulatory older adults , whether spatial-temporal measures of foot placement during gait can predict the likelihood of future falls or whether these measures are more likely to be indicative of adaptations associated with pre-existing fear of falling . DESIGN Prospect i ve cohort study . SETTING Baseline gait measurements were performed in a gait and balance laboratory ; subsequent history of falling was monitored prospect ively for 1 year in two self-care facilities . PARTICIPANTS Fourteen male and 61 female consecutive volunteers ( mean age = 82 , SD = 6 ) who were independent in activities of daily living and able to walk 10 m unaided . MEASUREMENTS Spatial gait parameters  were derived from digitized " footprints " ; temporal parameters were derived using footswitches . A clinical activity-based gait assessment was also performed . The dependent variables were pre-existing fear of falling ( reported at baseline ) and future falling ( experiencing one or more falls during the 1-year follow-up ) . MAIN RESULTS Reduced stride length , reduced speed , increased double-support time , and poorer clinical gait scores were associated with fear but showed little evidence of an independent association with falling . Conversely , increased stride-to-stride variability in stride length , speed , and double-support was associated independently with falling but showed little evidence of relationship to fear . Increased stride width showed some evidence of association with both falling and fear . Stride-to-stride variability in speed was the single best independent predictor of falling . CONCLUSIONS Changes in gait cited previously as risk factors for falling , i.e. , decreased stride length and speed and prolonged double support , may in fact be stabilizing adaptations related to fear 
    Output:
    