deficits of motor and sensory functions after stroke on the side contralateral to the 
 damaged hemisphere are often evident1 , 
 whereas the ipsilateral side may be primarily regarded as normal or unaffected . however , 
 there is increasing evidence of the presence of subtle motor deficits in motor performance 
 on the ipsilateral side as well2 , 3 .
ipsilateral motor deficits emerge during 
 the acute phase and demonstrate chronic persistence3,4,5 ; the reasons for ipsilateral motor deficits are still unclear . 

clinical assessment tools may not be sufficient for differentiating ipsilateral motor 
 deficits ; however , deficits in dexterous motor and coordination function on the ipsilateral 
 side have been identified in laboratory testing2 , 
 6,7,8 .
however , kinematic deficits in the ipsilateral upper limb in performance of various specific 
 motor tasks requiring dexterity and coordination , such as a tracking task , a goal - direction 
 movement , and a tapping task , have been found in recent studies2 , 6 , 8 , 11 . on the basis of these 
 observations , several possible mechanisms for ipsilateral motor deficits
have been 
 suggested , such as disrupted counterbalance of each hemisphere , dysfunction of the uncrossed 
 corticospinal track , or the different roles of both sides in hemispheric functions6 , 7 , 11,12,13,14,15 .
as mentioned above , patients with brain damage suffer from ipsilateral motor deficits in 
 performance of the ipsilateral upper limb .
until now , most studies of ipsilateral deficits 
 in stroke patients have concentrated on the motor , rather than sensory deficits .
therefore , the purpose of 
 the current study was to investigate the presence of motor and sensory deficits in the 
 ipsilateral upper limb , and to examine the correlation between the two variables in patients 
 with stroke using a tracking and reposition sense test .
fifty hemiparetic stroke patients ( 25 patients with right brain injury and 25 patients with 
 left brain injury ) referred to a local rehabilitation hospital were consecutively recruited 
 in the order of their registration .
the inclusion criteria were ; first ever stroke confirmed 
 by medical history and brain mri ; right handed individual verified by the edinburg 
 handedness inventory ; no symptoms of unilateral neglect or hemianopsia ; no cognitive problem 
 ( mini - mental state examination>24 points ) ; no apraxic behavior ( ideomotor apraxia score 
 developed by ambosoni et al .
( > 11 points)16 ; and no musculoskeletal dysfunction in the unaffected upper limb . 

we recruited 40 sex- and age - matched normal control subjects . to control the known effects 
 of hand asymmetry , the accuracy and proprioceptive tests were performed by the 20 control 
 subjects using their dominant right hand , and the remaining subjects used their non - dominant 
 left hand .
all subjects gave their written informed consent prior to participation , and this 
 study was approved by the local ethics committee .
tracking and joint position sense tests were conducted for the hand ipsilateral to the 
 damaged hemisphere of the patients , and with the corresponding hand of the same side of the 
 control subjects .
all subjects were seated in front of a table , with the forearm comfortably 
 supported and the elbow flexed at 90. a plastic frame with an embedded potentiometer was 
 used to measure the accuracy of movement and proprioceptive sense in the metacarpophalangeal 
 ( mp ) joints .
the potentiometer detected flexion / extension motion of the mp joint , and 
 transmitted the analog signal to a computer with analog - to - digital data acquisition 
 software , that sampled the signal at a frequency of 200  hz . in the tracking task , the subject was instructed to track the red target sine wave 
 displayed for 15 seconds on the computer screen as accurately as possible .
the response sine 
 wave made by the subject was displayed as a black solid line , which tracked up as the mp 
 joint was extended , and tracked down as the mp joint was flexed .
accuracy of the motor performance was 
 analyzed by an accuracy index ( ai ) , which was normalized to the range of motion of the mp 
 joint of each individual subject , and takes into account the differences between subjects in 
 the excursion of the target and response waves17.ai = 100(p  e)/p where e is the root mean square ( rms ) error between the target line and the response line , 
 and p is the size of the subject s target pattern , calculated as the rms difference between 
 the sine wave and the midline dividing the upper and lower phases of the sine wave .
the 
 degree of p is determined by the scale of the vertical axis of the range of subject s mp 
 joint motion .
prior to the evaluation , three practice trials were provided after one demonstration , using 
 sine waves which were different from the sine waves used in the actual test to prevent a 
 learning effect .
the joint position sense was evaluated on the mp joint ipsilateral to the 
 damaged brain hemisphere of the patients , and the joint on the corresponding side of the 
 control subjects .
in addition , the same experimental apparatus and environment used for the 
 performance of the tracking task were used .
the subjects were instructed to actively 
 reproduce the position of the mp joint which was passively positioned by the examiner .
three 
 different passively - positioned angles were randomly presented , in terms of 50% , 70% , and 90% 
 flexion of the total range of motion of the mp joint .
the mean value of three trials of the 
 joint reposition errors between the passively - positioned angles and the actively - positioned 
 angles was calculated .
the  test was performed to analyze the differences in sex distribution between 
 the patient and control groups .
the independent t - test was performed to determine the 
 significance of differences in age and accuracy of the tracking task / joint position sense . 
 in addition , correlation between the ai and joint position sense was investigated using 
 pearson s correlation coefficient .
chicago , il , usa ) was used for the 
 statistical analysis of all data , and statistical significance was accepted for p values 
 < 0.05 .
no significant differences were observed between the two 
 groups in terms of distribution of sex and age .
the meanssd of the accuracy index and 
 reposition error score of both groups are shown in table 2 . in terms of motor function ,
the stroke group showed a lower accuracy 
 index in the mp joint than the control group .
a higher score of reposition errors in the 
 joint reposition test in relation to sensory function was observed in the stroke group , 
 compared to the control group .
the results of the statistical analysis indicate that both 
 measures in the stroke group were significantly different from the control group 
 ( p<0.05 ) .
ipsilateral sensory deficits showed significant correlation with motor deficits 
 ( r= 0.549 ) ( p<0.001 ) ( table 2 ) .
in the current study , we attempted to assess motor function using a tracking task for 
 visuomotor coordination , and proprioceptive sense using a joint reposition test for the 
 ipsilateral upper limb .
our findings reveal a lower accuracy index in the tracking task , and 
 higher error scores in the joint reposition test in the stroke group , compared to sex- and 
 age - matched normal subjects .
in addition , there was a negative correlation between the motor 
 and sensory deficits , indicating stroke patients would have difficulty in performing 
 complicated motor tasks requiring delicate sensoriomotor functions using pure integrity of 
 movement accuracy and proprioceptive sense .
our present results are in accordance with those of several previous studies2 , 8 , 
 suggesting the presence of motor deficits in upper limbs ipsilateral to the damaged 
 hemisphere in the visuomotor tracking task .
a possible mechanism for the motor dysfunction 
 in the ipsilateral hemisphere of stroke patients has been suggested by previous studies , 
 which reported bilateral hemisphere activation when normal subjects executed a unilateral 
 upper limb task18,19,20,21 .
if functional integrity of both the right and left brain cortex is 
 necessary for normal motor control of the upper limb , it is expected that the ipsilateral 
 upper limb would be affected after stroke . in the present study ,
ipsilateral sensory 
 deficits related to proprioceptive sense were also observed . according to our findings
, 
 ipsilateral sensory deficits may be connected with bilateral hemisphere activation during 
 performance of motor tasks .
the primary sensory cortex ( s1 ) conveys efferent projection to 
 the posterior parietal cortex ( brodmann s area 5 and 7 ) , which is connected bilaterally 
 through the corpus callsosum .
therefore , as suggested by our results , it is possible that 
 disturbance of transcallosal transfer after unilateral brain damage may lead to ipsilateral 
 sensory deficits .
in addition , there is a close relationship between sensory and motor 
 function , because the posterior parietal cortex is connected with the frontal motor areas . 

thus , the posterior parietal cortex would have an effect on the initial movement and sensory 
 feedback during performance of a complex motor task22 . on this basis ,
the correlation shown in our study between 
 ipsilateral motor deficits and sensory deficits can be explained .
these findings imply that interest in the ipsilateral side of stroke patients should focus 
 on ipsilateral sensory deficits as well as ipsilateral motor deficits .
motor deficits of the 
 ipsilateral limbs of individuals with stroke have been reported in many studies ; besides , 
 our study showed sensory deficits related to proprioceptive sense . on the basis of these 
 results
, we think that the difficultly stroke patients experience in task performance using 
 the ipsilateral upper limb may be affected by both motor and sensory deficits .
studies on 
 recovery of motor deficits on the ipsilateral side after stroke are in progress .
jung et 
 al.14 reported that motor deficits in 
 the ipsilateral upper limb show maximal recovery within one month after onset of stroke , but 
 the deficits do not completely recover .
thus , it will be necessary to study the recovery of 
 ipsilateral sensory deficits after stroke onset , and we will be investigating this .
we 
 acknowledge that our study had some limitations , in that the effects of specific lesion 
 location and the extent of the damage were not identified .
therefore , future studies will be 
 required in order to determine more detailed mechanisms of other movement and sensory 
 deficits , other than proprioceptive sense , in the ipsilateral upper limb of patients with 
 unilateral brain injury .
   [ purpose ] previous studies have reported on motor deficits in the ipsilateral upper 
 limbs ( ul ) of a damaged brain hemisphere in motor tasks . however , little is known about 
 sensory deficits on the ipsilateral side . 
 therefore , we investigated whether both motor 
 and sensory function of the ipsilateral ul are affected in patients with stroke . 
 [ subjects 
 and methods ] fifty patients with unilateral stroke and 40 age- and sex- matched normal 
 subjects participated in this study . 
 subjects were evaluated on performance of a tracking 
 task for motor function , and by the joint reposition test for integrity of proprioceptive 
 sense in the ipsilateral ul . [ result ] the comparison of the stroke group and the control 
 group showed significant differences in performance of the tracking task and the joint 
 reposition test . 
 the accuracy index for the tracking task showed significant correlation 
 with the error score for the joint reposition test in the stroke group . 
 [ conclusion ] these 
 results suggest that the ipsilateral ul of stroke patients has impairment in sensory 
 function which is related to proprioceptive sense , along with motor deficits . 
 therefore , 
 we think that the difficulty stroke patients experience with motor tasks for the 
 ipsilateral ul is induced by diminished integrity of sensorimotor function due to both 
 sensory and motor deficits . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION