cerebrovascular diseases ( cvds ) are associated with balance disturbances , dependency in 
 performing daily living activities , and limited ambulation . as life expectancy increases spasticity is a speed - dependent resistance to the passive motion of muscles and tendons , 
 developing secondary to enhanced stretch reflexes in patients with upper motor neuron 
 lesions . spasticity is a major problem in rehabilitation programs , and it hampers patient 
 progress and may trigger severe complications2 , 3 . quantitative assessment of spasticity is 
 critical when gauging responses to medical treatment and physical therapy , and when making a 
 prognosis . at present , rather limited clinical scoring systems of spasticity , and 
 biomechanical and electrophysiological data , are used . electroneuromyographic evaluation of 
 the spinal reflex organization allows detailed follow - up of physiological changes . this measure , 
 and also the f reflex , assessed using various techniques , are employed to quantitate and 
 explore spasticity4 . transcutaneous electrical nerve stimulation ( tens ) is a rehabilitative form of physical 
 therapy used to treat pain . various types of nerve fiber are stimulated at different 
 frequencies , wavelengths , and amplitudes . tens delays the h reflex 
 through the 1a fibers , which mediate presynaptic inhibition8 . in the present study , we evaluated the utility of tens for patients with spasticity due to 
 cvd , who were undergoing rehabilitation , was evaluated using clinical scoring systems and 
 electrophysiological assessment . this study also aimed to explore whether tens affects 
 spasticity electrophysiologically , and the extent of the effects on clinical features . patients hospitalized in ankara physical therapy and rehabilitation training and research 
 hospital , who were participating in a rehabilitation program for hemiplegia with spasticity 
 in the lower extremity , were recruited . patients who had received any treatment for spasticity , who lacked spasticity , who had a 
 history of any systemic disease that might cause peripheral neuropathy , or symptoms of 
 radiculopathy in the lower extremities , who had suffered strokes less than 30 days prior , 
 who had a prior history of cerebrovascular disease , who had upper motor neuron damage on the 
 non - hemiplegic side , who could not co - operate , or who were obese , were excluded . aphasic and 
 geriatric patients were also excluded ; because their co - operation was lacking . patients with spasticity of at least ashworth grade 1 in the lower extremities were 
 included . the active motor power and spasticity of all patients reflex , and superficial and deep 
 sensorial examinations were performed . the time taken to walk 10  m by patients who could 
 walk was measured before and after tens . after a clinical evaluation , emg examinations were initially performed on healthy controls 
 and , later , on the affected sides of patients . all electrophysiological work was performed 
 in a calm , intermediately lit room with patients in the supine position . their feet extended 
 from the examination bed , commencing at the ankle joints , each of which was in the 90 
 neutral position ; the knee joint was at 180 of extension . all patients were asked to relax 
 their muscles as much as possible during the electrophysiological study . the h reflexes and 
 m responses of the gastrocnemius - soleus muscle were electrophysiologically recorded on both 
 the healthy and hemiplegic sides . subsequently , a single 30  min session of tens was applied 
 to the hemiplegic lower extremity . ten minutes later , the h reflexes and m responses were 
 re - assessed and compared with the pre - tens data . a nihon kohden neuropack  four - channel emg platform was used for measurements in the 
 single - channel mode . the active 
 electrode was placed on the gastrocnemius - soleus muscle , in a slightly medial position , 
 14  cm proximal to the junction of the achilles tendon and the heel . the reference electrode 
 was placed at the junction of the tendon and the heel , and a velcro ground electrode was 
 placed between the active electrode and the stimulator . the latter electrode was placed on 
 the fossae popliteal , to stimulate the tibial nerve , and the cathode was placed across the 
 active electrode . the stimulus intensity 
 was increased in steps of 2 ma , commencing at zero , and the combined action potentials of 
 the soleus muscle were recorded . the 
 peak - to - peak amplitudes and latencies of the h and m responses were measured . the latencies 
 were assessed at the point of separation of each response from the baseline . the 
 sensitivity , low frequency filter , and high frequency filter were 2  mv / dv , 200  hz , and 3 
 khz , respectively . stimuli were created randomly , 
 and delivered to the popliteal fossa with the posterior tibial nerve lying proximal to the 
 cathode . a rectangular flow 1  ms in duration , delivered every 2  s , served as the stimulus . the sweep speed and sensitivity were 10  ms and 2  mv / dv , respectively . subsequently , the largest h wave was determined by 
 varying the strength of the stimulus with the location of the stimulator unchanged . after all electrophysiological work was completed , and all wave amplitudes calculated , the 
 h / m maximum amplitude ratio was calculated for each patient by dividing the maximal 
 amplitude of the h reflex by that of the m responses from both the healthy and affected 
 sides . in addition , to evaluate alpha motor neuron excitability and the extent of 
 spasticity , the slopes of the rising sides of the h and m amplitude - stimulus severity slopes 
 were calculated using excel and the h slope , m slope , and h slope / m slope values were 
 obtained . tens was performed in the supine position with the feet hanging in a neutral manner . electrodes were placed bilaterally on the tibialis nerve , between the tendon of the muscle 
 and the medial malleolus ; thus the gastrocnemius muscle was included . the recording 
 electrodes used in the electrophysiological study were not removed . a systems 200e tens platform was used . this equipment has two output channels the flow 
 intensity in each channel can be adjusted independently . the frequency was 50  hz and the 
 pulse width was 100  ms in normal stimulation . the current intensity was not allowed to 
 exceed a mean of 50 ma and no contractions were noted . electrophysiological data were collected before and after tens , the same as 
 for the patient group . controls were positioned the same as patients , and tens was applied 
 for 30  min . electrophysiological data were gathered from only the right lower extremities of 
 the controls and the pre- and post - tens values were compared . the  , wilcoxon signed - rank , and kruskal - wallis tests , were used , as 
 appropriate , to evaluate the experimental parameters . the patient group with hemiplegia secondary to cvd numbered 27 [ 12 females ( 44.4% ) and 15 
 males ( 55.6% ) ] . a total of 24 healthy subjects [ 10 females ( 41.7% ) and 14 males ( 58.3% ) ] 
 served as controls . the mean ages of the patients and controls were 60.9312.8 and 
 49.886.85  years , respectively . the mean heights of the patients and controls were 
 160.858.99 and 165.38 + 8.56  cm , respectively . the mean age , but fourteen ( 51.9% ) and 13 ( 48.l% ) patients respectively had left- and right - side hemiplegia . thromboembolic and 
 hemorrhagic stroke were the principal causes of hemiplegia in 21 ( 77.8% ) and 6 ( 22.2% ) 
 patients , respectively . superficial sensory nerve 
 examinations revealed hypoesthesia in 10 patients ( 37% ) , but 17 were normal ( 63% ) . the deep 
 tendon reflexes ( dtrs ) on the hemiplegic sides were normal in the upper extremity of one 
 patient ( 3.7% ) but hyperactive in 26 ( 96.3% ) ; the lower extremity on the affected side was 
 hyperactive in all patients . on the healthy sides , the dtrs were normative in both the upper 
 and lower extremities of 26 ( 96.3% ) patients , and hyperactive in one ( 3.7% ) . no significant 
 difference in the mean pre- and post - tens lower - extremity dtrs on the hemiplegic side was 
 found ( p>0.05 ) . the values of the spasticity parameters before and after tens differed significantly in the 
 patient group ( table 1table 1.change in the spasticity between pre- and post - tensashworth 1ashworth 2ashworth 3pre - tens10 ( 37%)13 ( 48.2%)4 ( 14.8%)post - tens14 ( 51.9%)11 ( 40.7%)2 ( 7.4% ) all p values < 0.05 ) . fourteen patients were able to walk , either with support or independently , but 13 were not . after tens , 11 patients 
 exhibited increased walking speeds and 3 reduced speeds . when patient hemiplegic and healthy lower extremities were electrophysiologically compared , 
 the mean maxima of the h reflex , the h / m ratio , the h slope , and h slope / m slope ratio , were 
 significantly greater on the affected side . in addition , the mean m response amplitude was 
 significantly different ( greater on the healthy side ) . the differences in the h / m maximum 
 and h slope / m slope ratios were particularly marked ( table 2table 2.electrophysiological variables of the healthy and affected sides of the 
 patientsvariablehealthy sideaffected sideh max amp ( mv)1,669.851559.792,899.701,698.69h max lat ( msec)31.212.1831.082.28 m max amp ( mv)8,735.892,820.527,439.892,825.16 m max lat ( msec)4.900.444.930.40h / m max amp ( mv)0.190.160.420.22h slope0.010.0090.030.22 m slope0.030.0060.030.006h / m slope0.40.320.910.43 ) . the h maximum amplitude values were higher on the spastic hemiplegic side than on the 
 healthy side . the h / m ratio , h slope , and h slope / m slope ratio were higher on the affected 
 side . however , the mean m amplitude was higher on the normal than on the hemiplegic side . 
 the mean h reflex amplitude , the h / m amplitude ratio , the h maximum latency , the h slope , 
 and the h / m slope ratio , differed significantly pre- and post - tens on the hemiplegic 
 side . the post - tens electrophysiological changes in the control group were similar to those in 
 the patient group . the h maximum amplitude , the h / m ratio , the m maximum amplitude , and the 
 m slope ratio , decreased , whereas the h and m maximum latencies increased , with statistical 
 significance . the duration of disease was positively associated with the mean h maximum amplitude , the 
 h / m ratio , and the h / m slope ratio ; however , no association was statistically significant . the h maximum latency was lowest in patients with disease durations greater than 100 
 days . higher mean h maximum amplitudes , h / m ratios , and h slopes evident as spasticity worsened . however , only the mean h slope differed significantly among the spasticity subgroups , with 
 significant differences being found between subgroups i and iii , and ii and iii , in parallel 
 with worsening of spasticity . tens significantly reduced spasticity scores and increased the walking speed . on the 
 spastic side , tens significantly reduced the m amplitude and increased the h reflex 
 amplitude , the h / m maximum amplitude ratio , the h slope , and the h slope / m slope ratio . 
 also , the mean patient h reflex amplitude , the h / m ratio , the h slope , and the h slope / m 
 slope ratio , decreased significantly , and the h reflex maximum latency increased , after 
 tens . in controls , tens significantly decreased the h maximum amplitude , the h / m ratio , the 
 m maximum amplitude , and the m slope ratio , and lengthened the h and m maximum latencies . 
 the h maximum latency was the only variable affected by lesional duration . the mean h 
 maximum amplitude , the h / m ratio , and the mean h slope increased as spasticity worsened on 
 the ashworth scale . explored changes in the spasticity of patients with medulla spinalis injuries 
 after tens , and found there were short - term reductions in spasticity9 . robinson et al . applied 20  min electrical stimulation to 
 the quadriceps muscles of patients with medulla spinalis injuries and reported a significant 
 decrease in leg spasticity10 . cho et al . 
 found that a single session of high - frequency tens significantly improved the spasticity 
 ( for less than 1 day ) of chronic stroke patients . similarly , tens reduced the spasticity of stroke 
 patients , and repeat tens reduced the hyperactive tension reflexes of the plantar flexors , 
 and the passive resistance to plantar flexor movement11 . in a study that included acute stroke patients , tens applied to 
 acupuncture points for 3 weeks decreased plantar flexor spasticity and increased 
 dorsiflexion of the ankle joint . in chronic stroke patients , however , ankle joint 
 dorsoflexion was strengthened by stimulation , and muscle co - contraction was decreased . in 
 addition repeated skin stimulation was 
 advocated , to increase the number of cortical fields represented12 . in a study that included chronic stroke patients , addition of tens to a 20-session rehabilitation program decreased spasticity by 30% and 
 markedly improved muscle strength13 . park 
 et al . showed that balance , walking , and the functional activity of chronic stroke patients 
 improved after 30 tens sessions ( each 30  min in duration ) , and a combination of exercise and 
 tens increased the activation of pathways associated with proprioception and balance14 . in the present study , a significant 
 decrease in spasticity and an increase in walking speed were evident after acute hemiplegic 
 the patients in a rehabilitation program received a single session of tens . fisher reported that the m amplitudes of patients with first - motor neuron diseases 
 decreased , after tens , compared to the amplitudes of polyneuropathic patients15 . angel and hoffman , who first showed that 
 the h / m ratio was increased in spastic patients , reported mean ratios of 9.17 and 0.48 in 
 the extremities of control and spastic groups , respectively . the excitability of alpha motor 
 neurons increased when various physiopathological mechanisms were in play ; therefore , the 
 responses to stimuli carried by 1a afferent fibers increased16 . garcia - mullin and mayer reported mean h / m ratios of 0.33 and 0.46 
 on the healthy and paretic sides , respectively , of spastic hemiplegic stroke patients in 
 whom the disease duration was longer than 90 days17 . bakhtiary showed that spasticity was reduced by electrical stimulation , but no significant 
 change in the h reflex amplitude was evident . also , the h / m maximum ratio did not change , 
 and this was attributed to muscle weakness caused by stimulation18 . gaft et al . noted significant decreases in both 
 spasticity and the h reflex amplitude after stimulation . in the present study , significant 
 differences were found in the m response and h reflex amplitude between the healthy and 
 affected sides of spastic the hemiplegic stroke patients . the mean maximum amplitudes of the 
 h reflexes of the triceps surae were 1,669 and 2,899  mv on the healthy and paretic sides , 
 respectively , and the difference was significant . the difference in the h / m ratio between 
 the healthy and plegic sides was also significant19 . huang et al . reported that the h / m maximum and h2/h1 ratios were not adequate for defining 
 the extent of spasticity as assessed by the ashworth scale . the mean h / m maximum and h2/h1 
 values increased in stroke patients , compared to healthy controls , but the m maximum ratio 
 did not significantly differ between the groups . the h2/h1 and m maximum ratios did not 
 significantly correlate with other measures of spasticity . in contrast to other previous 
 studies , huang et al . concluded that the mas value correlated with the h / m ratio20 . in the present study , we noted a decrease 
 in the m amplitude on the spastic side was observed , whereas the h reflex amplitude and the 
 h / m maximum amplitude ratio , increased . higashi et al . found that the change in the h slope / m slope ratio was more significant on 
 the spastic than the healthy side , and no significant difference in the h / m maxima of the 
 two sides was evident . as the h slope / m slope graph is bell - shaped , such data are more 
 compatible with the brunnstrom stage of hemiplegic patients than are other indicators . in 
 conclusion , the h slope/ m slope ratio is primarily useful for objectively evaluating the 
 extent of spasticity , and the excitability of the motor neuron pool of the spastic sides of 
 hemiplegic patients21 . measured the excitability of the motor neuron pool and compared the h / m ratios , the h 
 maximum amplitude , and the h slope / m slope ratio , in spastic and normal individuals , and 
 found there were marked differences between the two groups . they concluded , the h slope / m 
 slope ratio was particularly useful for evaluating motor neuron pool excitability22 . in the present study , steeper h slope and 
 greater h slope / m slope ratio on the spastic ( compared to healthy ) side of hemiplegic 
 patients prior to tens were observed . one study evaluating the electrophysiological components of the h reflex and f wave 
 compared the pre- and post - tens h reflexes , and f wave latencies and amplitudes , and 
 reported the reduction in spasticity was associated with electrophysiologically proven 
 decreases in the h reflex amplitude , the f wave amplitude , and the h / m and f / m ratios23 . in another study , tens was applied 
 segmentally and heterosegmentally to the median nerve of the wrist , and to the common 
 peroneal nerve ( placebo ) . the h reflex latencies increased in 75% of the patients in the 
 experimental groups , but the h amplitude did not change significantly . aydin et al . compared tens with baclofen , the commonest drug prescribed to treat spasticity 
 in patients with medulla spinalis injuries . significant improvements in all parameters , 
 except pain , were evident in the tens group , and they were associated with decreases in the 
 h amplitude and h / m ratio , and the m response . the electrophysiological and clinical changes 
 did not differ significantly between the tens and baclofen group25 . tekeoglu et al . also reported that tens reduced 
 spasticity in stroke patients , and improved their capacity to engage in activities of daily 
 living , concluding that tens effectively improved motor function26 . in the present study , a single session of tens resulted in significant clinical inhibition 
 of spasticity ; however , lower extremity strength did not improve . on the spastic side , tens 
 significantly decreased the mean h reflex amplitude , the h / m ratio , the h slope , and the h 
 slope / m slope ratio ; and increased the h reflex maximum latency . this study had some 
 limitation walking speed was not measured after several tens applications . in conclusion , tens for hemiplegic patients with spastic lower extremities due to cvd 
 markedly improved clinical parameters and significantly changed electrophysiological 
 variables . the results of this study suggest that tens is effective when used to manage 
 spasticity .
to investigate whether transcutaneous electrical nerve stimulation ( tens ) mitigates the 
 spasticity of hemiplegic stroke patients , as assessed by electrophysiological variables , 
 and the effects , if any , on the clinical appearance of spasticity . 
 [ subjects and methods ] 
 twenty - seven subjects who had acute hemiplegia and 24 healthy people as the control group , 
 were enrolled in this study . 
 some of the acute cerebrovascular disease patients could 
 walk . 
 subjects who did not have spasticity , who were taking antispasticity medicine , or 
 had a previous episode of cerebrovascular disease were excluded . 
 the walking speed of the 
 patients was recorded before and after tens . 
 emg examinations were performed on the 
 healthy controls and in the affected side of the patients . 
 a 30-minute single session of 
 tens was applied to lower extremity . at 10 minutes after tens 
 , the emg examinations were 
 repeated . 
 [ results ] a statistically significant decrease in the spasticity variables , and 
 increased walking speed were found post - tens . 
 the lower m amplitude and higher h reflex 
 amplitude , h / m maximum amplitude ratio , h slope , and h slope / m slope ratio on the spastic 
 side were found to be statistically significant . 
 [ conclusion ] tens application for 
 hemiplegic patients with spastic lower extremities due to cerebrovascular disease resulted 
 in marked improvement in clinical scales of spasticity and significant changes in the 
 electrophysiological variables .