assessment of functional capacity is important for identifying the physical implications of 
 stroke , since it is currently considered the main cause of serious long - term disability in 
 adults1 , impairing physical , 
 psychological , and social functions2 . 
 after a stroke ,
individuals remain with several residual impairments , especially those 
 related to motor function , which lead to reduced functional ability3 . in this sense ,
instruments that adequately capture several 
 aspects of disability progression / regression are essential within clinical settings , 
 implement more specific and effective disability management4 .
the use of functional tests is sometimes impossible during rehabilitation , due to the need 
 for specialized equipment , expertise and space . in this sense
, it is already known that 
 aerobic capacity assessed on a treadmill , by analyzing the oxygen consumption 
 ( vo2 ) is the gold standard measure of functional performance for disabled 
 individuals5 . however , the widespread 
 utilization of this method is limited by expertise , associated with the need for the use of 
 specific and expensive equipment6 . on the 
 other hand , an easy assessment , such as the six - minute walking test ( 6mwt ) ,
which is 
 routinely used to assess functional walking capacity of stroke individuals4 , 7 , 8 requires only a chronometer and a 30-meter 
 corridor to be performed9,10,11 .
the 
 establishment of valid and simple ways to use alternative measures of functional capacity 
 after stroke would be , therefore , clinically relevant .
the use of a simple tool for the 
 assessment of functional capacity may allow clinicians to obtain clinically useful methods 
 to estimate an important outcome , which can determine the degree of constraint imposed by 
 the stroke , as well as its importance , by being a factor in diagnosis , prognosis , and a 
 strong predictor of mortality12 .
an easily administered questionnaire was developed to assess functional capacity by the 
 prediction of oxygen consumption ( vo2 ) without the need for maximal 
 cardiopulmonary exercise testing13 .
the 
 duke activity status index ( dasi ) is a short , simple questionnaire that can be administered 
 to patients with physical limitations .
it has been previously validated with physiological 
 measurements , such as vo2 in cardiac patients14 , 15 .
although it was 
 originally designed to evaluate patients with cardiovascular diseases , the dasi has also 
 been shown to be valid and appropriate for the assessment of functional capacity of disabled 
 individuals , such as those with moderate to severe chronic obstructive pulmonary disease 
 ( copd)16 . in order to allow for its 
 clinical use in individuals with stroke , this study investigated the associations between 
 the dasi scores and valid and extensively used functional capacity measures ( distance 
 covered and oxygen consumption obtained during the 6mwt ) .
therefore , the specific research question for this study was : are there significant 
 associations between the dasi scores and the distance covered and relative vo2 
 during the 6mwt in individuals with chronic stroke ?
individuals with chronic stroke were recruited from the general community of the city of 
 belo horizonte , brazil , according to the following criteria : were 20  years old , had a mean 
 time since the onset of a unilateral stroke between 1 and 5  years , were able to walk with or 
 without assistive devices , and had no cognitive deficits , as determined by an 
 education - adjusted cutoff score on the mini - mental state examination : 18/19 for the 
 individuals with illiteracy and 24/25 for individuals with a basic education17 , and no other neurological or orthopedic 
 disorders .
this study was approved by the ethics review board of the universidade federal de 
 minas gerais , and all participants provided written consent , prior to data collection .
initially , the participants underwent a physical examination and an interview for the 
 collection of clinical and demographical data , which included age , gender , body mass , 
 height , time since stroke onset , number of medications , associated diseases , and habitual 
 walking speed ( 10-meter walking test)18 , 19 .
at least 500  ml of water was provided 
 prior to the tests , to guarantee normal hydration .
the questions were read 
 loud and repeated if necessary , and none of the participants had difficulties in 
 understanding them .
then , the participants performed the 6mwt without metabolic monitoring 
 equipment , and the distance covered was recorded .
the test was carried out in a 30-meter 
 corridor according to the procedures and recommendations of the american thoracic 
 society9 , which were adapted to the 
 brazilian portuguese language11 .
then , 
 the individuals performed the 6mwt test with a portable metabolic system , which was 
 previously calibrated .
the means of the relative vo2 
 ( mlkgmin ) values for the final three 
 minutes of the 6mwt ( steady state condition ) were recorded for analyses20 . the brazilian version of the dasi was employed to assess the individuals perceived 
 functional capacity14 , 16 .
its scores reflect the role of physiological factors in 
 the individual s daily life and consider all important spheres related to functional 
 capacity status , such as personal care , ambulation , household tasks , sexual function , and 
 recreational activities21 .
it is composed 
 of 12 items which describe daily living activities , with their correspondent metabolic 
 equivalents ( mets ) , and are answered with yes or no .
the 
 dasi scores ranged from 0 to 58.2 , and higher scores reflect higher functional capacity14 , 16 .
the distance covered during the 6mwt , which appropriately reflects functional capacity 
 status , was recorded for analyses10 , 22 .
the cortex metamax 3b is a portable metabolic system that allows online data transmission 
 for a distance up to 800 meters .
the measures are adjusted in real time , according to the 
 environmental test conditions , by means of temperature and internal pressure sensors , and an 
 electronic barometer .
its face mask has a low dead space volume and two inspiratory valves 
 with low inspiratory resistance , and it allows the removal of exhaled air during testing , 
 which leads to improved quality of the analyzed gases .
the instrument has been shown to have 
 adequate validity and reliability , when used in various activities with individuals with 
 stroke23 and to reflect the capture , 
 transport and peripheral oxygen consumption .
descriptive statistics and tests for normality ( shapiro - wilk test ) were carried out for all 
 outcomes .
pearson correlation coefficients were calculated to explore the relationships 
 between the dasi scores , distance covered , and the relative vo2 during the 6mwt . 

the magnitudes of the correlations were classified as follows : low or none 
 ( 0.00<r < 0.25 ) , fair ( 0.25<r < 0.50 ) , 
 moderate to good ( 0.50<r<0.75 ) , and good to excellent 
 ( r>0.75)24 .
all 
 analyses were carried out with the spss software ( release 17.0 ) with a significance level of 
 5% .
they had a mean age of 
 58.613  years , and a mean time since the onset of stroke ranging from 12 to 60 months .
they 
 had a mean dasi score of 27.314.4 , a mean oxygen consumption of 9.62.3 
 mlkgmin , and a mean distance covered of 
 325.2140.2  m during the 6mwt .
their characteristics are described in table 1table 1.characteristics of the participantscharacteristicn=31age ( years ) , mean ( sd)58.6 ( 13)gender , men , n ( % ) 17 ( 54.8)body mass index ( kg / m ) , mean ( sd)25.7 ( 4.2)time since the onset of stroke ( months ) , mean 
 ( sd)28.3 ( 15.1)number of medications , mean ( sd)4.6 ( 2.1)associated diseases , mean ( sd)1.8 ( .96)mmse ( scores : 030 ) , mean ( sd)25.6 ( 3)habitual walking speed ( m / s ) , mean ( sd)0.8 ( 0.3)dasi ( scores : 058.2 ) , mean ( sd)27.3 ( 14.4)6mwt ( distance , in meters ) , mean ( sd)325.2 ( 140.2)relative vo2 
 ( ml.kg.min ) , mean ( sd)9.6 ( 2.3)sd : standard deviation ; mmes : mini - mental state examination ; dasi : duke activity 
 status index ; 6mwt : 6-minute walking test ; vo2 : oxygen consumption .
sd : standard deviation ; mmes : mini - mental state examination ; dasi : duke activity 
 status index ; 6mwt : 6-minute walking test ; vo2 : oxygen consumption moderate to good correlation coefficients were found between the dasi scores and the 
 distance covered during the 6mwt ( r=0.68 , p<0.0001 ) .
significant and 
 fair associations were also found between the dasi scores and the relative vo2 
 obtained during the 6mwt ( r=0.45 , p= 0.03 ) .
to the best of our knowledge , this was the first study to use a brief and self - administered 
 questionnaire to assess functional capacity in individuals with stroke , and the results 
 answered the main question of this study .
this study used a sample of ambulatory , 
 individuals with chronic stroke with high functional levels , as demonstrated by their 
 walking capacity and speed .
significant correlations were found between the dasi scores , the 
 relative vo2 , and the distance covered during the 6mwt . in agreement with the 
 findings of previous studies with other health conditions14 , 25 ,
the dasi scores were 
 significantly associated with both the physiological and physical performance measures .
the 
 results of the present study supported the use of the dasi as a tool to assist in clinical 
 evaluations related to the functional capacity of individuals with chronic stroke .
previous studies observed significant associations between the dasi scores and several 
 outcomes in cardiac patients , such as metabolic equivalent26 , 27 , new york heart 
 association28 , canadian cardiovascular 
 society of angina29 , and body mass 
 index27 .
the associations between the 
 dasi scores and the distance covered during the 6mwt were previously investigated in 
 cardiac6 and in copd patients16 , and moderate to good correlations were 
 found between the investigated variables ( r=0.68 ; p<0.001 and 
 r=0.58 , p<0.0001 , respectively )
. additionally , bagur et al.28 also found moderate to good correlations 
 between the dasi scores and the distance covered during the 6mwt in patients , who underwent 
 transcatheter aortic valve implantation at baseline ( r=0.55 , p<0.0001 ) 
 and at six - month follow - up ( r=0.66 , p<0.0001 ) .
these results are in line 
 with the findings of the present study , which found correlation coefficients of similar 
 magnitudes .
these similarities could be explained by the fact that all studies had 
 participants with chronic diseases and several disabilities .
in addition , individuals with 
 stroke have some cardiac dysfunctions as the main associated morbidity and risk factors for 
 new episodes of stroke2 .
no previous studies were found that investigated the associations between relative 
 vo2 during the 6mwt and the dasi scores .
several studies found associations 
 between the dasi scores and peak vo2 during maximal tests on cycle and arm 
 ergometers , as well on treadmills with various populations , such as patients with vascular 
 diseases ( r=0.51 , p<0.001)14 , copd patients ( 0.34<r<0.38 , 
 p<0.0001)16 , and cardiac patients 
 ( 0.58<r<0.81 , p<0.0001)13 . in the present study , fair correlations between the relative 
 vo2 during the 6mwt and dasi scores were found .
regarding these findings , 
 jakovljevic et al.30 pointed out that the 
 ability of the skeletal muscles to extract oxygen is decreased after stroke , but their 
 cardiac function and pumping capability were preserved .
additionally , it was found that 
 individuals with stroke showed reduced blood flow , higher lactic acid production , and 
 decreased capacity to oxidase free fatty acids by their paretic muscles31 .
these findings could partially explain the results of the 
 present study , since fair correlations were found .
however , it is well known that stroke 
 individuals exhibit a constellation of impairments , as well as comorbidities , which were not 
 investigated in the present study , and these could have influenced the results .
it is important to notice that this was the first study to analyze the associations between 
 self - reported and direct measures of functional capacity and found associations of 
 magnitudes ranging from fair to good .
these results are in agreement with those of 
 teixeira - salmela , devaraj , and olney32 , 
 who found good relationships between self - reported physical activity levels and observed 
 performances of individuals with chronic stroke .
taking together , these findings reinforce 
 the importance of taking the patients ` perceptions into consideration during the 
 rehabilitation process . due to the design of this study , causal relationships can not be determined .
the sample size 
 was composed of individuals at the chronic stages after stroke , who had a time since the 
 onset of the stroke ranging from one to five years , were able to walk independently , and had 
 good functional levels ( mean walking speed of 0.81 m / s and mean distance covered during the 
 6mwt of 325 meters ) . in this sense , the results of the present study can not be generalized 
 to individuals with different functional levels and at the acute and subacute phases after 
 stroke33 .
for instance , it is well known that 
 the major motor deficit after stroke is weakness , which is found in 80% of stroke survivors . 

it is important 
 for health professionals to focus on the implications of a given health condition on an 
 individual s life14 .
thus , some 
 instruments should be used based upon their impact on their real life contexts .
the dasi has 
 been demonstrated to be a useful tool for clinical and research purposes , since it provides 
 insights regarding function that may not be captured by physiological measures14 , 16 .
the results of the present study revealed positive , significant , and moderate to good 
 associations between the dasi scores and the distance covered during the 6mwt and positive , 
 significant , and fair correlations between the dasi scores and the relative vo2 
 during the 6mwt .
these findings support the utility and validity of a self - report measure in 
 providing an indirect index of functional capacity .
 [ purpose ] the aim of this study was to investigate the associations between self - reported 
 and valid performance - based measures of functional capacity in individuals with chronic 
 stroke . [ subjects and methods ] self - reported measures of functional capacity of 31 
 individuals with chronic stroke were assessed by the duke activity status index scores , 
 whereas performance - based measures were assessed by the distance covered ( in meters ) and 
 oxygen consumption ( relative oxygen consumption , in 
 mlkg1min1 ) during the six - minute walking 
 test . 
 [ results ] the subjects had a mean age of 58.613  years and a mean time since the 
 onset of stroke of 28.315.1 months . 
 they had a mean duke activity status index of 
 27.314.4 , mean distance covered of 325.2140.2 m , and mean relative oxygen consumption of 
 9.62.3 mlkg1min1 . 
 significant , positive , and 
 moderate to good correlation coefficients were found between the duke activity status 
 index scores and the distance covered during the six - minute walking test 
 ( r=0.68 ) . 
 significant , positive , and fair associations were also found 
 between the duke activity status index scores and relative oxygen consumption values 
 obtained during the six - minute walking test ( r=0.45 ) . 
 [ conclusion ] the 
 findings of the present study support the clinical use of the duke activity status index 
 as a tool to assist in clinical evaluations of functional capacity of individuals with 
 chronic stroke . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION