patients with stroke show various muscle abnormalities , including a combination of 
 denervation , disuse , remodeling , and spasticity1 .
abnormal gaits cause flexion and extension synergy patterns due to compensatory actions of 
 muscles , etc .
, on the unaffected side , impairment of proprioceptive sensibility , and 
 abnormal coordination of stiffened muscles of the lower limb3 . as a substitute of stair climbing exercise , inclined treadmill walking training , which is 
 aimed at improving these gait disorders , is being considered as an essential means for 
 indoor and outdoor movements of the disabled , the elderly , or pregnant women who are unable 
 to use stairs4 . however , rhea et al.5 stated that treadmill walking training , 
 compared with walking on flat ground , is characterized by a shorter step length .
oh , kim , 
 and woo6 argued that treadmill walking 
 training has negative effects on gait asymmetry .
sensory elements play an important part in 
 compensating for these weaknesses7 , and 
 rhythmic auditory stimulation ( ras ) can be used as a complementing intervention8 . in this intervention ,
the external auditory 
 sense of rhythms generates rhythmic and more symmetrical alternate movements in the lower 
 limbs of stroke patients who show gait asymmetry6 , 
 9 .
existing studies have not shown 
 consistent results regarding the effects of treadmill walking training on the gait of stroke 
 patients .
in particular , with regard to balance and gait , which are essential for the 
 activity and participation of stroke patients , there are no systematic studies showing the 
 effects of inclined treadmill walking training with ras thus far .
therefore , the purpose of this study was to identify the effects of inclined treadmill 
 walking training with ras on balance and gait in stroke patients .
the study population included 30 patients diagnosed with stroke at b hospital located in 
 gangwon - do , south korea who provided written consent and understood the purpose of this 
 experiment .
they were randomly assigned to three groups of 10 subjects each : the inclined 
 treadmill with ras training group ( experimental group 1 , g1 ) , the inclined treadmill without 
 ras training group ( g2 ) , and the only treadmill training group ( g3 ) .
this study was approved 
 by the institutional review board of the korea national university of transportation 
 ( approval no .
the subjects in each group walked on a treadmill ( s23 t ; taeha 
 mechatronics , republic of korea ) . for g1
, ras was additionally applied using a metronome 
 ( fretway metro , fretway , usa ) . regarding treadmill speed for g1 , g2 , and g3 ,
the patients 
 most favorite speed was adopted in the first week , and this speed was increased by 5% in the 
 second week .
an additional 5% increase was made in the third week and no increase was made 
 in the fourth week .
although a 
 treadmill incline of 10% was set in the second and third weeks , this increase was not 
 applied for those who were unable to perform treadmill walking at this inclination .
for the beat of the metronome in g1 , the 
 subjects cadence measured using a wireless three - axis accelerometer was applied in the 
 first week6 .
this beat was increased by 5% 
 increments in the second and third weeks , without any change in the fourth week9 .
each group performed its respective 
 training five times a week over a 4-week period .
the timed up and go ( tug ) test and 
 the berg balance scale ( bbs ) test were performed to measure the subjects balance ability . 
 for the measurement of their gait ability , spatiotemporal gait abilities such as walking 
 speed , cadence , single limb support of the affected side ( sls ) , and symmetric index ( si ) 
 were measured using the 6-minute test ( 6mwt ) and the wireless three - axis accelerometer 
 ( g - walk ; bts s.t.a . , italy ) .
pasw 18.0 was used for statistical analysis . chi - squared test and kruskal - wallis h test 

were performed to test homogeneity between the two groups , and the results showed that the 
 two groups were homogeneous ( table 1table 1.general characteristics of the subjectsg1g2g3gender ( m / f)6/46/35/4age ( yrs)50.8  14.456.3  7.161.2  13.0height ( cm)167.8  10.1165.7  8.8160.8  9.6weight ( kg)69.8  10.962.3  11.165.8  7.4onset ( months)16.4  10.3 13.6  8.517.1  8.4diagnosis ( h / i)7/35/44/5hemiside ( rt / lt)6/43/64/5 m : male , f : female , h : hemorrhage , i : infarction , rt : right , lt : left )
. wilcoxon signed rank test was used to examine changes in the dependent 
 variables within each group , and kruskal - wallis h test was used to compare changes between 
 the two groups .
mann - whitney u test with bonferroni correction was used for post - hoc 
 comparisons .
m : male , f : female , h : hemorrhage , i : infarction , rt : right , lt : left
comparison of the variables before and after the experiment within each group showed 
 statistically significant improvements in all variables except for the tug in g3 ( p<0.05 ; 
 table 2table 2.comparison of change in balance and gait between the three groupsg1g2g3pre - trainingpost - trainingpre - trainingpost - trainingpre - trainingpost - trainingtug ( sec)32.6  12.330.00  12.3 * 28.2  9.326.8  9.131.2  6.330.6  6.2bbs ( score)34.6  6.742.4  6.8 * 36.7  6.740.7  6.137.7  8.340.1  8.16mwt ( sec)109.5  35.3130.6  35.2 * 120.5  34.5135.3  34.080.6  39.090.0  40.9speed ( m / s)1.2  0.61.5  0.7 * 0.9  0.51.0  0.51.1  0.61.2  0.6cadence ( s / m)85.5  23.399.4  20.1 * 85.4  24.090.7  23.164.1  29.267.7  28.6sls ( % ) 24.3  8.341.9  8.2 * 31.6  9.338.9  7.333.3  7.037.2  8.3si0.5  0.20.7  0.2 * 0.4  0.30.5  0.30.4
 0.30.6  0.3tug : timed up and go test ; bbs : berg balance scale ; 6mwt : 6  m walking test ; cadence : 
 steps / min ; sls : single limb support ; si : symmetric index .
mean  standard deviation , 
 * intra - group , statistically significant at p<0.05 , statistically 
 significant compared with g1 at p<0.05 , statistically significant 
 compared with g2 at p<0.05 ) .
with regard to group differences , g1 showed statistically significant higher 
 improvements in all variables when compared with g2 and g3 , and g2 exhibited statistically 
 significant higher improvements in the tug , bbs , 6mwt , walking speed , and si when compared 
 with g3 ( table 2 ) .
tug : timed up and go test ; bbs : berg balance scale ; 6mwt : 6  m walking test ; cadence : 
 steps / min ; sls : single limb support ; si : symmetric index .
mean  standard deviation , 
 * intra - group , statistically significant at p<0.05 , statistically 
 significant compared with g1 at p<0.05 , statistically significant 
 compared with g2 at p<0.05
the study showed that g1 was more effective than g2 and g3 in improving balance and gait . 

previous studies have reported that repetitive rhythms combined with movements of patients 
 with central nerve system damage were effective in improving their ability to perform 
 exercises9,10,11,12,13 .
in addition , repetitive 
 rhythms enhanced coordination and improved gait because of improved movements in the pelvis 
 and the shoulder girdle14 . in the present 
 study , g1 showed statistically significant higher improvements in the tug and bbs when 
 compared with g2 and g3 , whereas g3 did not exhibit statistically significant differences 
 within the group .
this result suggests that the training for g1 was more effective than that 
 for g2 or g3 in improving the balance in stroke patients .
in addition , regarding gait , g1 
 showed statistically significant higher improvements in all variables when compared with g2 
 and g3 , and g2 exhibited statistically significant higher improvements in 6mwt , walking 
 speed , and si when compared with g3 .
all three groups showed improvements in gait endurance , which can be attributed to the 
 effects of task - specific training for 30 minutes a day .
rhythms affect brain activities through encoding and , thus , can provide the feedback of 
 nerve roots and generate instinctive movements16 .
the more effective outcome in balance , gait speed , and cadence 
 could be due to improvements in sls following the ras - induced rhythmical walking .
thaut et 
 al.17 reported that the application of 
 treadmill walking training with ras in stroke patients led to statistically significant 
 improvements in gait symmetry .
this result is in agreement with that of the present study . 
 for the route of ras ,
as the body subconsciously responds to the signals of rhythms , unlike 
 the general auditory route , these signals are transmitted to the cerebral cortex through the 
 supraspinal auditory system18 .
therefore , 
 improvements in balance and gait could have been more significant in the present study . however , our study had a limitation in that the study sample was small and included only 
 patients with stroke who were capable of walking
. therefore , the results of this study 
 can not be generalized for all stroke patients .
thus , future longer - term studies with a 
 larger sample size should be conducted .
 [ purpose ] the purpose of this study was to determine if an inclined treadmill with 
 rhythmic auditory stimulation gait training can improve balance and gait ability in stroke 
 patients . 
 [ subjects and methods ] thirty participants were randomly divided into three 
 groups : inclined treadmill with rhythmic auditory stimulation training group ( n=10 ) , 
 inclined treadmill training group ( n=10 ) , and treadmill training group ( n=10 ) . 
 for all 
 groups , the training was conducted for 4 weeks , 30 minutes per session , 5 times per week . 
 
 two subjects dropped out before study completion . 
 [ results ] all variables of balance and 
 gait , except for the timed up and go test in the treadmill group , significantly improved 
 in all groups . 
 moreover , all variables showed a more significant improvement in the 
 inclined treadmill with rhythmic auditory stimulation group when compared with the other 
 groups . timed up and go test , berg balance scale , 6  m walking test , walking speed , and 
 symmetric index were significantly improved in the inclined treadmill group when compared 
 with the treadmill group . [ conclusion ] thus , for stroke patients receiving gait training , 
 inclined treadmill with rhythmic auditory stimulation training was more effective in 
 maintaining balance and gait than inclined treadmill without rhythmic auditory stimulation 
 or only treadmill training . 