stroke is the result of bleeding in brain tissues or the blockade of blood flow supplied to 
 the brain , due to cerebrovascular disease , cardiac disorder , or diabetes , etc . most stroke 
 patients show symptoms of motor abnormality and sensory disturbance as well as disturbance 
 of consciousness , language , and cognition , and paralysis or paresis1 . the control ability of central nervous system on the 
 affected side of hemiplegic patients is impaired , and imbalance of protagonist and 
 antagonistic muscle and excessive muscle tone , spasticity , are shown . the reasons for the 
 lowering of balance ability are often proprioceptive injury and reduction of muscle tone . about 65% of patients with stroke usually experience the loss of tactile sense , protective 
 reaction and proprioception2 , 3 . in particular , left - right imbalance and asymmetric posture due to decline in mobility are 
 characteristics of stoke . these characteristics bias the center of gravity to the unaffected 
 side lower limb and weaken subjects ability to maintain the body center within the base of 
 support , resulting in a serious problem with postural control due to difficulty in 
 controlling balance in the standing position , and also affects the righting and equilibrium 
 reactions4 , 5 . in static standing , the center of plantar pressure prominently exhibits the anteriolateral 
 sway . in order to maintain balance , a compensatory ankle strategy is used to allow the 
 ground reaction force to effectively act on the unaffected side foot , which also causes 
 muscular weakness and asymmetric postures . the reasons for this condition are explained by 
 the lack of weight bearing ability or muscular control disorder on the affected side lower 
 limb6 , 7 , and modification of the muscle recruitment pattern and the delayed 
 contraction of paretic muscles are shown8 . stroke patients ability to properly react to various environments and tasks is decreased 
 because of decline in left / right weight transfer ability , time of affected side lower limb 
 support , and limit of stability . also , their physical disturbance in standing is increased 
 as much as two times , compared with normal persons of the same age9,10,11 . in exercise imagery training , the imagery induces 
 information processing activity similar to performance of the real task , promoting the 
 learning of motor function13 , 14 . the results of functional magnetic response imaging 
 ( fmri ) , which was used to examine the validity of exercise imagery training , suggest that 
 both the primary motor cortex and the sensory fields of brain15 , as well as the dorsal premotor cortex , superior parietal lobe and 
 intra - parietal sulcus are activated by exercise imagery training16 . in exercise imagery training , stroke patients with limited mobility can activate the brain 
 circuits by imagining movements , and active participation can be induced through the 
 training17 , 18 . in stroke patients who performed exercise imagery training , 
 symmetry of the gait pattern improved in the stance phase on the affected side,19 and the training can also be used to 
 improve the relearning of daily tasks after acute stroke20 . stroke patients who were asked to imagine normal gait to train the 
 normal movement of feet , showed improved gait functions22 . although research regarding exercise imagery for stroke patients has been variously 
 implemented , the enhancement of exercise performance with respect to the improvement of 
 upper limbs function , gait function , and change of brain activation has been frequently 
 studied . thus , this study examined the effects of exercise imagery on the balance ability of stroke 
 patients in proprioception training . the subjects of this study were 36 patients hospitalized for the treatment of stroke in a 
 hospital located in the republic of korea . all the subjects and their guardians voluntarily agreed to 
 participate in the study after receiving explanations regarding the purpose and procedures 
 of the experiment , and signed an informed consent statement before its start . the criteria 
 for selecting the subjects were as follows : more than 6 months since the onset of 
 non - traumatic and unilateral stroke , a score of more than 24 in the korean version of the 
 mini mental state examination , a score of less than 2.26 in the vividness of movement 
 imagery questions , the ability to stand independently for more than three minutes , the 
 ability to walk farther than 10 m , and no orthopedic diseases that would have affected 
 standing balance . the proprioception training program of the 18 patients who met the inclusion criteria was 
 conducted in two phases for 30 minutes a session , 5 days a week , for 8 weeks . the program 
 used in this study was implemented by correcting and supplementing the suggestions of the 
 aged examined23 , 24 . for the initial 4 weeks , training was conducted on a balance pad 
 ( balance pad , airex , swiss ) and consisted of 5 tasks . patients were allowed to take a break 
 of 10 seconds after performing each task , and 5 trials were regarded as 1 set , and a total 
 of 5 sets were performed in 30 minutes . from 5 weeks to 8 weeks , the training was conducted 
 on a balance board ( dynair ballkissen , togu , germany ) and consisted of 5 tasks . it was 
 conducted in the same way as the initial 4 weeks , and the details of the training items are 
 described in table 1table 1.proprioceptive training programtraining with balance pad ( 14 week)training with balance board ( 58 week)a.standing with two feet support posture.f.in standing position , moving the weight left and right 
 maximally.b.in standing position , moving both heels of feet up and down.g.in standing position , moving the weight forward and backward 
 maximally.c.in standing position , bending and stretching both knees.h.in standing position , bending and stretching both knees.d.while standing with widening each feet forward and backward , 
 placing the unaffected side foot on a floor andthe affected side foot on balance 
 pad , putting the body forward with bending and stretching knees.i.in standing position , moving both heels of feet up and down.e.in standing position , to keep your eyes closed.j.in sitting a mat on position , sit - to - stand on a balance board .. the training was conducted under the instruction and support of therapists , 
 given the difficulty of the training , to ensure the safety of subjects . after the proprioception training , the 18 patients performed motor imagery training in the 
 cognitive rehabilitation room at a proper temperature , with no noise , in order to enhance 
 concentration on the motor imagery training . to lower the stress and anxiety of the 
 subjects , and relax the body and mind , armchairs with a backrest were used so that subjects 
 could comfortably lean on them , and close their eyes25 . the objective of mobility imagery is to imagine the inner sensory 
 information during actual movements of body from the first person view , and the purpose of 
 visual imagery is to imagine one s own movements of the body from a third person view . for 
 the exact performance of motor imagery , cognitive functions and imagery of the movements 
 were tested through the mini mental state examination - korea version and the vividness of 
 movement imagery questions26 . in this study , the mobility imagery training was conducted to encourage the subjects to 
 feel the position senses of the ankle , knee and hip joints , the peripheral muscles , and 
 sole . the subjects actively participated in the proprioception training program . in the 
 motor imagery training , therapists asked the patients to imagine the contents of the 
 proprioception program for 5 minutes , by directly reading aloud to them while reading , the 
 subjects were asked some questions in order to ensure they were adequately performing the 
 imagery training . the proprioception program was consisted of 4 sets performed in 25 minutes 
 before the motor imagery training . the outcome measures of pre - intervention and 4 and 8 weeks were compared 
 using repeated measures anova . the general characteristics of the study subjects are displayed in table 2table 2.the general characteristics of the subjects ( n=36)variablemtg ( n=18)ptg ( n=18)gendermale9 ( 50%)11 ( 61.1%)female9 ( 50%)7 ( 38.9%)age<6514 ( 77.8%)14 ( 77.8%)654 ( 22.2%)4 ( 22.2%)diagnosisinfarction15 ( 83.3%)15 ( 83.3%)hemorrhage3 ( 16.7%)3 ( 16.7%)affected sideleft9 ( 50%)11 ( 61.1%)right9 ( 50%)7 ( 38.9%)onset time ( month)11.5  1.5811.61  2.28values are n ( % ) or mean  sd , mtg : motor imagery training group , ptg : proprioceptive 
 training group . values are n ( % ) or mean  sd , mtg : motor imagery training group , ptg : proprioceptive 
 training group in both groups , significant improvements were seen in the outcome measures with time 
 ( p<0.05 ) , and the motor imagery training group showed significantly greater improvements 
 than the proprioception training group ( p<0.05 ) ( table 3table 3.comparison of variables between the two groups ( n=36 ) groupvariablek - bbstugauwbraapwbruapwbrjpsemtg ( n=18)pre40.50  9.2429.63  10.0215.22  9.119.68  4.149.7  2.653.99  1.614 weeks42.00  8.0027.06  9.2812.15  7.047.72  3.448.09  3.132.98  1.148 weeks44.61  6.0824.89  8.029.48  5.805.34  2.025.71  2.351.76  0.63ptg ( n=18)pre39.33  5.3229.39  8.5214.88  4.1410.53  6.009.82  6.954.39  1.024 weeks40.17  4.8227.98  7.6813.43  3.449.46  5.979.02  6.273.81  0.898 weeks41.22  4.4326.38  7.1611.74  2.028.11  5.358.10  5.793.11  0.80p<0.05 , mean  sd , mtg : motor imagery training group , ptg : 
 proprioceptive training group , k - bbs : korean version of berg balance scale , tug : timed 
 up and go test , auwbr : affected side / unaffected side weight bearing ratio , aapwbr : 
 affected side anterior / posterior weight bearing ratio , uapwbr : unaffected side 
 anterior / posterior weight bearing ratio , jpse : joint position sense error . comparison 
 of the time dependent variable each group calculated by repeated measure anova , 
 : pre4 weeks , : 48 weeks , : pre8 weeks 
 ( p<0.05 ) . ) . p<0.05 , mean  sd , mtg : motor imagery training group , ptg : 
 proprioceptive training group , k - bbs : korean version of berg balance scale , tug : timed 
 up and go test , auwbr : affected side / unaffected side weight bearing ratio , aapwbr : 
 affected side anterior / posterior weight bearing ratio , uapwbr : unaffected side 
 anterior / posterior weight bearing ratio , jpse : joint position sense error . comparison 
 of the time dependent variable each group calculated by repeated measure anova , 
 : pre4 weeks , : 48 weeks , : pre8 weeks 
 ( p<0.05 ) . this study aimed to provide reference data for planning the rehabilitation of stroke 
 patients , by comparing the effects of proprioception training with motor imagery and 
 conventional proprioception training performed for 8 weeks . the results of this study show that k - bbs had significantly increased and tug had 
 significantly decreased in both groups after the training , and the changes of the motor 
 imagery training group were more significant than those of the conventional proprioception 
 training group . one 
 reported that the joint scope of lower limbs and the static and dynamic balance index 
 increased after motor imagery training27 , 
 and the other that the gait velocity significantly increased after training to enhance 
 balance ability9 . since the ability to 
 maintain balance in the standing position is a fundamental factor of stable independent gait 
 and sensitively affects gait velocity28 , 
 we think that the gait velocity increased and the tug time was decreased in the present 
 study , due to the rise of the k - bbs scores . increased weight bearing on the unaffected lower limb of stroke patients largely affects 
 the movement of the whole body . therefore , the asymmetry of weight bearing on the lower 
 limbs should be evaluated and weight bearing on the affected side needs to be corrected . this study evaluated the affected / unaffected side weight bearing ratios and the affected and 
 unaffected sides anterior / posterior weight bearing ratios . our results show that the 
 affected and unaffected sides weight bearing ratios and the affected and unaffected sides 
 anterior / posterior weight bearing ratios of both groups significantly decreased after the 
 training , and the motor imagery training group showed more significant changes than those of 
 the conventional proprioception training group . one reported that when motor imagery training was added to 
 conventional movement training , the symmetry of muscle activity and its timing improved in 
 stroke patients29 , and the other reported 
 that by preliminarily practicing daily activities through motor imagery , postural symmetry 
 and postural control in the standing position were enhanced21 . thus , these results show that it helps to enhance the symmetry of 
 hemiplegic patients affected and unaffected sides weight bearing and improve their affected 
 and unaffected sides anterior / posterior weight bearing ratios of hemiplegic patients . the joint position sense test is a method of evaluating the position of body segments 
 without visual support , and this study conducted position sense tests of the ankle joint . our results show that in both groups , the errors of position sense was decreased 
 significantly after the training , and that the motor imagery training group showed more 
 significant changes than the conventional proprioception training group . one compared motor imagery and actual 
 movement using brain scanning , and reported that both tasks resulted in the formation of the 
 same neural networks in the premotor cortex , parietal lobe and cerebellum30 , and the other that motor imagery 
 increased dynamic balance ability by activating the neural system31 . these results suggest that in the motor imagery training 
 with proprioception program , activation of the cerebrum and cerebellum affected 
 proprioception , and the visual and vestibular organs responsible for balance ability , in 
 particular , that the activation of the proprioception sensing the position and movements of 
 joints affects the balance ability . in the present study proprioception with motor imagery training showed greater improvement 
 than conventional proprioception training of the weight bearing ratio of the unaffected 
 affected sides , indicating that the balance ability , postural symmetry and proprioception of 
 the subjects were enhanced . these results suggest that proprioception with motor imagery can 
 be used as a treatment option to improve the balance ability of stroke patients . motor 
 imagery can be conducted anywhere and at any time without treatment tools , and can be used 
 together with a variety of long - term rehabilitation approaches for the treatment of patients 
 with severe disabilities22 . in addition , 
 motor imagery requires little energy consumption and motor skills can be learned effectively 
 in motor imagery training without fear of injury . limitations of this study were the small number of participants , making it difficult to 
 generalize the results , the activities of the subjects were not controlled except during the 
 training time , the joint position sense error used to measure proprioception ability through 
 posture reproduction were not controlled for age , and joint position sense was measured only 
 on the affected side , not both the affected and unaffected sides . thus , further studies of 
 motor imagery training for the enhancement of stroke patients function addressing these 
 issues are required .
[ purpose ] the purpose of the present study was to examine and compare the effects of 
 proprioceptive training accompanied by motor imagery training and general proprioceptive 
 training on the balance of stroke patients . 
 [ subjects and methods ] thirty - six stroke 
 patients were randomly assigned to either an experimental group of 18 patients or a 
 control group of 18 patients . 
 the experimental group was given motor imagery training for 
 5 minutes and proprioceptive training for 25 minutes , while the control group was given 
 proprioceptive training for 30 minutes . 
 each session and training program was implemented 
 5 times a week for 8 weeks . 
 the korean version of the berg balance scale ( k - bbs ) , timed up 
 and go test ( tug ) , weight bearing ratio ( afa-50 , alfoots , republic of korea ) , and joint 
 position sense error ( dualer iq inclinometer , jtech medical , usa ) were measured . 
 [ results ] 
 both groups showed improvements in k - bbs , tug , weight bearing ratio , and joint position 
 sense error . 
 the measures of the experimental group showed greater improvement than the 
 control group . 
 [ conclusion ] motor imagery training , which is not subject to time 
 restrictions , is not very risky and can be used as an effective treatment method for 
 improving the balance ability of stroke patients .