cerebrovascular disease - related mortality rates have been increasing , and 1 out of every 4 
 cerebrovascular disease patients dies within a month after the onset of disease1 . among the surviving patients , 1530% become 
 severely handicapped , and 40% are left with functional deficits , resulting in problems with 
 the major components of functional independence : motor , sensory , and cognitive 
 functions2 , 3 . cognitive function refers to the ability to understand the things that occur in daily life . it is the capacity to adapt to various situations as one begins activities , plans and 
 considers issues , and resolves problems . the cognitive domain includes the abilities of 
 concentration , memory , planning , systematization , problem solving , abstraction , and use of 
 language4 . because movements can not be 
 performed without intent , cognitive processing is crucial for motor control5 . during the rehabilitative training process , 
 stroke patients with decreased cognitive ability can not adequately utilize the cognitive 
 function needed for motor learning6 . thus , 
 the normal mechanisms of postural control that were once automatic , such as the maintenance 
 of a standing position , walking , and dual - task performance , are temporarily or permanently 
 lost , and are changed into a conscious and slow response with a limited extent7 , 8 . thus , the evaluation of cognitive function in patients with early stroke is important for 
 planning treatment for their functional recovery and return to daily life9 . in addition to cognitive function , walking is one of the major physical functions that is 
 highly affected by stroke10 . stroke 
 patients exhibit inefficient walking because of decreased dynamic balance ability , as well 
 as decreased musculoskeletal and cardiovascular function , and expend a significant amount of 
 energy compensating for this deficiency11 . compared with healthy persons , therefore , stroke patients have lower 
 walking speeds and shorter duration of walking . their daily functions are also limited and 
 they can not complete certain simultaneous tasks , such as conversing while walking12 . the relationship between cognition and motor control after neurological damage due to 
 factors such as stroke has significant implications for understanding the recovery of motor 
 function . thus , it has been the center of much research , and the number of studies 
 investigating the role of cognition and walking in elderly populations and clinical disease 
 research has increased13 , 14 . cognitive - motor interference refers to the phenomenon that occurs when 1 or 2 tasks that 
 interfere with each other are being performed , such as engaging in cognitive and motor tasks 
 simultaneously15 . interference between 
 cognitive tasks and motor control activities ( such as walking ) is important for functional 
 improvement in patients with neurological deficits . thus , the therapist must address both 
 cognitive and motor training in planning rehabilitation therapy16 . a dual task requires subjects to perform complex tasks simultaneously , and emphasizes the 
 role of cognition and concentration using a dual - task method that involves a cognitive task 
 combined with postural and walking control15 , 17 . typically , the concurrent performance of 
 motor and cognitive tasks in dual - task training affects the performance of one or both 
 tasks18 . various studies on the 
 interaction between cognitive tasks and cognitive characteristics , and between motor tasks 
 and dynamic characteristics are under way19 . according to the task integration hypothesis . single - task training does not permit the concurrent performance of 2 
 tasks , whereas dual - task training allows the coordination of various tasks via the 
 simultaneous performance of 2 or more tasks17 . however , the majority of gait training for stroke patients focuses 
 on functional recovery via exercise under single - task , rather than dual - task , conditions . 
 therefore , the therapeutic approaches available currently fall short of addressing cognitive 
 deficits . thus , the present study aimed to investigate the effects of dual - task training including a 
 cognitive task component on the cognitive and walking abilities of chronic stroke patients 
 using objective measurement equipment and functional evaluation tools . the present study included 20 patients who consented to participate in the study from among 
 patients who had received a diagnosis of hemiparalysis due to stroke . the study was 
 performed at the c hospital in gwangju , began in august 2012 , and lasted for 4 weeks . all 
 the subjects voluntarily consented to participate in this study prior to its initiation . data collection was carried out after approval had been granted by the institutional review 
 board of donshin university . the 20 stroke patients were randomly assigned to 2 groups ( n = 10 per group ) . the 
 experimental group received dual - task gait training with cognitive tasks , whereas the 
 control group received single - task gait training . to evaluate the cognitive and walking abilities of stroke patients , we used the stroop 
 test , timed up and go ( tug ) test , 10-meter walk test ( 10mwt ) , figure - of-8 walking test 
 ( f8wt ) , and dynamic gait index ( dgi ) . three repeated measurements were taken ( before the 
 intervention , after the intervention , and 2 weeks after intervention ) . the assessment involved 
 showing the subjects words written using inks of various colors , and having the subjects 
 state the color of the ink20 , 21 . the tug test is an assessment tool that quickly assesses basic motor and balance control . it is currently being used to assess the elderly , as well as patients with stroke , 
 parkinson s disease , and arthritic diseases22 . the tug test measures the time it takes a subject to rise from an 
 armchair , walk 3 m , and then return to the chair and sit down . the tug test was administered 
 under both the single - task and dual - task conditions . for the 10mwt , a walkway of 14  m was measured and marked with marks at 2 and 12  m. the 
 person taking the measurement assured the safety of the subjects . the time taken by the 
 subjects to walk the 10  m between the 2 and 12  m marks was recorded23 . for the f8wt , distances of approximately 5 feet ( 1.5 m ) and 4 feet ( 1.2 m ) were measured . cones were placed at either end of this area , and the subjects stood in the center , facing 
 the front . the subjects chose the direction in which to walk and walked at a natural gait 
 speed when ready around the two cones , finally returning to the start position , thereby 
 drawing a figure - of-8 . the parameters measured include speed ( time to completion ) , number of 
 steps taken during the performance , accuracy ( whether the subject deviated from the walking 
 direction ) , and continuity of walking24 . the dgi test is comprised of 8 different gait tasks including walking on a level surface , 
 walking while changing gait speeds , walking with vertical or horizontal head turns , walking 
 with pivot turns , stepping over or around obstacles , and walking up and downstairs . subjects performance of each test item was rated on a 4-point scale ( 03 ) , with the total 
 score ranging between 0 and 2425 . in the present study , the speed and number of steps were evaluated , whereas accuracy and 
 continuity of walking were not . single - task and dual - task gait trainings were conducted 30  min per day , 3 days a week , for 
 a total of 4 weeks . the single - task gait training group performed gait training based on the 
 research of silsupadol et al . and silsupadol et al . with modified and supplemental methods 
 to meet the needs of stroke patients17 , 26 . the dual - task walking group performed a 
 cognitive task concurrently with the single - task training program . while moving during 
 dual - task training , changes in priority are divided into fixed priority ( fp ) and variable 
 priority ( vp ) . in the present study , vp conditions were applied so that participants had to 
 give the same priority to the 2 tasks . normal distribution of the data 
 was confirmed using the shapiro - wilk test . a repeated measures 2-way analysis of variance 
 ( anova ) was performed to compare changes in cognition and walking according to the 2 types 
 of exercise ( dual - task training or single - task training ) and the time points of each 
 training condition ( pre - training , post - training , or follow - up ) . a multiple comparison post 
 hoc analysis was also performed using bonferroni s multiple comparisons test . the average age of the dual - task training ( dt ) 
 group was 58.4  years , and that of the single - task training ( st ) group was 58.2  years . the 
 average height and weight of the dt group were 164.1  cm and 67.7  kg , respectively , and those 
 of the st group were 160.9  cm and 61.2  kg . disease duration was 16.6 months in the dt group 
 and 19.3 months in the st group . the dt group scored an average of 26.8 points in the korean 
 version of the mini - mental state examination ( k - mmse ) test and the st group scored an 
 average of 26.1 points ( table 1table 1 . general characteristics of subjectssingle - task training group ( n = 10)dual - task training group ( n = 10)age ( years)58.2  8.0758.4  7.58height ( cm)160.9 9.11164.4  6.59weight ( kg)61.2  6.6067.7  10.07prevalence ( months)19.3  14.1216.6  11.88k - mmse ( score)26.1  2.4226.8  1.99 ) . all values are the mean  sd . the results of the 2-way anova performed to examine the interaction between the training 
 groups and measurement time points ( to analyze cognitive function based on the stroop test 
 performances ) did not reveal a significant difference in the interactions between 
 measurement time points and training groups . there was a significant difference in the 
 number of performances according to the measurement time point ( f = 6.49 , p = 0.016 ) . the 
 results of the post hoc test showed an absence of significant differences between the pre- 
 and post - intervention time points ; while there was a significant difference in the 
 comparison between the pre - intervention and follow - up time points ( p = 0.028 ) , no 
 significant difference was observed between the post - intervention and follow - up time points . finally , there was a significant main effect of group ( f = 5.29 , p = 0.033 ) ( table 2table 2 . stroop test performance ( unit : no . of correct answers)before interventionafter interventionfollow upsingle - task training group32.50  14.3033.10 13.0734.20  14.80dual - task training group40.70  15.6851.00  15.8852.10  16.62*values are represented as mean  sd . * p < 0.05 relative to the single - task 
 training group before intervention by 2-way anova ) . * p < 0.05 relative to the single - task 
 training group before intervention by 2-way anova the average and standard deviation values of dynamic balance ability according to training 
 group and measurement time points were obtained from the tug time measured under single - task 
 conditions . moreover , there 
 was a significant difference in the change in speed according to measurement time points ( f 
 = 12.23 , p = 0.002 ) . the results of the post hoc test revealed the presence of a significant 
 difference between the pre- and post - intervention time points ( p = 0.004 ) , as well as of a 
 significant difference in the comparison of the pre - intervention and follow - up time points 
 ( p = 0.015 ) . in addition , there was a significant difference between the post - intervention 
 and follow - up time points ( p = 0.001 ) . finally , there was no significant difference in the 
 speed in either of the training groups ( table 
 3table 3 . tug test times under single tasks after dual - task training ( unit : sec)before interventionafter interventionfollow upsingle - task training group33.88  19.8630.39  22.6931.64  22.51dual - task training group31.34  19.5421.66  14.9722.66  14.97*values are represented as mean  sd . * p < 0.05 relative to the single - task 
 training group before intervention by 2-way anova . p < 0.05 relative to 
 the single - task training group after intervention by 2-way anova ) . * p < 0.05 relative to the single - task 
 training group before intervention by 2-way anova . p < 0.05 relative to 
 the single - task training group after intervention by 2-way anova the average and standard deviation values of dynamic balance ability according to training 
 group and measurement time points were obtained from the tug time measured under dual - task 
 conditions . there was no 
 significant difference in the interactions between measurement time points and training 
 group . however , there was a significant difference in the change in speed according to the 
 measurement time points ( f = 8.094 , p = 0.010 ) . the results of the post hoc test revealed 
 the presence of a significant difference between the pre- and post - intervention time points 
 ( p = 0.019 ) ; however , there was no significant difference between the pre - intervention and 
 follow - up time points . in addition , there was no significant difference between the 
 post - intervention and follow - up time points . there was no significant difference in the 
 speed in either of the training groups ( table 
 4table 4 . tug test times under dual tasks after dual - task training ( unit : sec)before interventionafter interventionfollow upsingle - task training group42.41  24.4040.41  22.8840.60 values are represented as mean  sd the average and standard deviation values of walking ability according to training group 
 and measurement time points were obtained by measuring the walking speed during the 10mwt . there was no 
 significant difference in the interactions between measurement time points and training 
 groups . however , there was a significant difference in the change in speed according to 
 measurement time points ( f = 14.688 , p = 0.000 ) . the results of the post hoc test revealed 
 the presence of a significant difference between the pre- and post - intervention time points 
 ( p = 0.001 ) , as well as between the pre - intervention and follow - up time points ( p = 0.006 ) . 
 in contrast , there was no significant difference in the comparison of the post - intervention 
 and follow - up time points . finally , there was no significant difference in the speed in 
 either of the training groups ( table 
 5table 5 . ten - meter walk test times ( unit : sec)before interventionafter interventionfollow upsingle - task training group30.86  14.8527.46  14.6528.90  14.58dual - task training group26.20  11.9318.16  12.1719.44  12.16values are represented as mean  sd ) . values are represented as mean  sd the average and standard deviation values of walking ability according to training group 
 and measurement time points were obtained by measuring the walking speed during the f8wt . there was no significant 
 difference in the interactions between measurement time points and training groups . moreover , there was no significant difference in the speed according to the measurement time 
 points , and no significant difference in the speed in either of the training groups ( table 6table 6 . figure - of-8 walk test times ( unit : sec)before interventionafter interventionfollow upsingle - task training group28.60  14.6127.10  19.6325.03  16.63dual - task training group24.48  13.1719.76  14.3321.74  15.40values are represented as mean  sd ) . values are represented as mean  sd the average and standard deviation values of walking ability according to training group 
 and measurement time points were obtained by measuring the steps taken during the f8wt . there was no significant difference in the 
 interactions between measurement time points and patient groups . in addition , there was no 
 significant difference in the change in the number of steps according to the measurement 
 time points , and no significant difference in the number of steps in either of the training 
 groups ( table 7table 7 . number of steps in the figure - of-8 walk test ( unit : step)before interventionafter interventionfollow upsingle - task training group35.20  17.5435.50  18.2235.60  18.08dual - task training group27.50  11.8929.60  10.9430.50 * p < 0.05 relative to the single - task 
 training group before intervention by 2-way anova . p < 0.05 relative to 
 the single - task training group after intervention by 2-way anova ) . * p < 0.05 relative to the single - task 
 training group before intervention by 2-way anova . p < 0.05 relative to 
 the single - task training group after intervention by 2-way anova the mean and standard deviations of dgis by group and measurement time are shown in table 8table 8 . the dynamic gait index values ( unit : score)before interventionafter interventionfollow upsingle - task training group10.30  5.2010.00  5.539.60  5.14dual - task training group13.00  5.8815.20  6.3515.20  6.35values are represented as mean  sd . significant differences were observed in the correlation between measurement 
 time points and training groups . the present study sought to investigate the effects of 4 weeks of dual - task training 
 including a cognitive task component on cognitive function and walking ability of stroke 
 patients using functional evaluation tools . the evaluation of cognitive function of stroke patients is important for the identification 
 of treatment strategies for functional recovery and their return to daily living27 . , the effect of 
 different performance levels among the subjects was minimized by specifying the reaction 
 time as the number of items performed within a given time . cognitive function increased with time , and differences were observed in the degree of 
 improvement in the stroop test according to training group . the dt group displayed greater 
 improvement than the st group , and these improved cognitive capacities were sustained at the 
 follow - up , which was performed 2 weeks after the end of the intervention . divided 45 elderly subjects into dual - task and single - task training groups 
 and studied the effects of dual - task balance training on cognition and concurrent standing 
 postural control . their results show that the dual - task group had significantly improved 
 performance compared to the single - task group in the stroop test28 . that study also showed that balance training for the 
 elderly under dual - task conditions led to improvement in dual - task performance during 
 standing postural control . conducted a dual - task training combined with aerobic training for depressed 
 elderly subjects . their data showed improvements in cognitive assessments , including the 
 stroop test , which led them to suggest that dual - task training is a safe and useful approach 
 for cognitive function training29 . walking is the most basic means of human transport in daily life , and is the movement that 
 is most easily performed concurrently with other tasks , such as conversing with another 
 person or moving an object30 . hemiplegia 
 resulting from stroke has serious effects on an individual s walking ability . even when 
 functional walking is possible , it is different from the walking of a healthy person . various capacities , including the maintenance of appropriate walking speed , endurance , 
 curved - path walking , and balance while walking , are required24 , 31 for independent walking 
 in daily life . cho et al . studied the effects of lower extremity circuit training based on a task - oriented 
 training program on the walking ability of stroke patients , and proved that there were 
 significant improvements in straight - line and curved - line walking speed32 . seo et al . reported that 4 weeks of a dual - task training program with vp conditions 
 effectively improved the static balance , dynamic balance , and walking abilities of patients 
 with stroke - induced hemiplegia33 . in 
 addition , lee et al . found that the training group with vp conditions exhibited 
 statistically significant differences in tug single and tug double tasks compared with other 
 training groups . there was also a statistically significant difference in the dynamic gait 
 index ( dgi ) score34 . in the present study , tug was performed under single - task and dual - task conditions to 
 evaluate dynamic balance ability . in addition , the 10mwt , dgi , and the f8wt were used to 
 evaluate walking ability . under single - task conditions , tug gait speed increased with time 
 in both groups . in single - task conditions , tug speed remained increased at 2 weeks after the 
 end of the intervention . we observed that , under dual - task conditions , both training groups exhibited significant 
 increases in walking speed in the tug and 10mwt with time . we think that the gait - training 
 program , which was performed identically by both training groups , influenced the 
 improvements of the dt group as well as those of the st group . the pattern of change in dgi 
 was different between the two groups : the dt group showed higher increases in dgi than the 
 st group . there were no differences between the groups regarding improvements with time in the f8wt , 
 as measured by speed and number of steps . this result was likely due to inadequate 
 intervention in the gait - training program components that involve curved paths . the present study was performed to investigate the effects of dual - task training with a 
 cognitive task component on cognition and walking of stroke patients . the sample size of our study was small ; 
 therefore , we could not draw generalized conclusions from our results . the gait - training 
 program showed limited improvement in complex evaluation tasks requiring a sense of 
 direction , such as the f8wt . this may be attributable to the fact that the gait - training 
 program , selected as the intervention method , did not include a variety of training 
 components . further research using a gait - training program with more diverse training 
 components would help to identify a broader rehabilitation strategy for clinical use .
[ purpose ] to determine the effect of dual - task training with cognitive tasks on 
 cognitive and walking ability after stroke . 
 [ subjects and methods ] twenty patients 
 diagnosed with stroke participated in this study . 
 all participants were receiving a 
 traditional rehabilitation program 5 days a week . 
 dual - task and single - task training were 
 additionally performed for 4 weeks , 3 days a week . 
 the stroop test , timed up and go ( tug ) 
 test , 10-meter walk test ( 10mwt ) , and figure - of-8 walk test ( f8wt ) were used to measure 
 cognitive and walking abilities and were evaluated 3 times ( before and after training and 
 at the 2-week follow - up ) . 
 [ results ] dual - task training improved cognitive and walking 
 abilities , and dual - task training subjects performance was better than single - task 
 training subjects performance . 
 in addition , these training benefits were maintained for 2 
 weeks . 
 [ conclusion ] dual - task training improves cognitive and walking abilities of 
 patients with stroke .