parkinson s disease ( pd ) was first known as shaking palsy , a term coined in 1817 by james 
 parkinson . it is a progressive neurologic disturbance in which the incidence rate increases 
 with age1 . when approximately 6080% of the dopamine produced by the 
 substantia nigra dopaminergic neurons has been lost , the extrapyramidal system can no longer 
 effectively promote movements , and the symptoms of pd appear . the clinical symptoms include 
 hypokinesia , bradykinesia , postural instability , rigidity , and tremor3 . the gait of patients with pd is 
 characterized by reduced gait speed and short steps , improper trunk rotation or arm swings , 
 difficulties in changes of direction , shuffling gait pattern , or acceleration gait 
 pattern4 . many studies have been conducted on the gait of patients with pd . to improve the gait of 
 patients with pd , research into signals began in 19425 , and gait analysis was conducted in relation to external cues in 
 19676 . until recently , research into the 
 effects of methods using external cues has been conducted for various methods of improving 
 gait in pd patients1 , 7,8,9 . in their reviews of the gaits of pd patients with application of 
 external cues , rubinstein et al.10 and 
 darmon et al.11 advised that external 
 cues could significantly improve the gaits of patients with pd or their gait - related 
 activities . as external information in the form of visual or auditory cues is known to 
 improve motor performance and motor learning12 , 13 , most studies on motor learning have 
 generally used feedback such as training with visual or auditory cues . recently , studies have been conducted on the use of feedback such as vibration stimuli . haridas and zehr14 reported that the 
 sensory feedback during gait provided by stimuli through the skin caused reflex activities 
 during upper and lower extremity movements and affected the activity of the central pattern 
 generator ( cpg ) . when applied to the muscles , vibration acts as powerful proprioceptive 
 stimulus , strongly affecting the motion perception of not only healthy people but also 
 patients with various neurological disorders15 . in a spatiotemporal exploratory study of three patients with left 
 unilateral neglect , when work was performed while vibration stimuli were applied to the 
 muscles , the subjects detected remarkably more objects16 . sorensen et al.17 found that vibration stimuli applied to the ankles played an 
 important role in controlling posture and balance during gait because the stimuli caused the 
 lower extremity to provide information about the movement of the center of gravity to the 
 central nervous system . by reviewing previous studies related to improvement of the gait of patients with pd , it 
 can be seen that studies on motion perception or vibration stimuli are insufficient , 
 although many studies have been conducted on the dependency on external cues in many 
 approaches for improving motor control or gait ability in patients with pd . therefore , the 
 purpose of this study was to compare temporal and spatial gait parameters while applying 
 vibration in patients with pd . the subjects had an average age of 61.825.57 , 
 an average height of 155.363.71  cm , and an average weight of 60.154.38  kg . approval for 
 the study was obtained from the institutional review board of the national evidence - based 
 healthcare collaborating agency , and written informed consent was obtained from each patient 
 before starting the study . eight vibrators ( 10  g , diameter of 1  cm ) were made especially for this study . they were 
 attached to the muscle bellies ( tibialis anterior , gastrocnemius , biceps femoris , and rectus 
 femoris ) on both sides of the lower extremities of the subjects . the subjects wore short 
 pants to minimize external stimuli , and were barefoot . to identify the effects of vibration 
 stimuli during walking , subjects were tested with respect to spatiotemporal gait parameters 
 with and without vibration in both lower extremities using a motion analysis system . a hawk 
 digital system ( 60  hz , motion analysis , santa rosa , ca , usa ) was used to measure the 
 spatiotemporal parameters during walking . the amplified motion analysis signals were sampled 
 online with the evart 5.0 software and were analyzed using the cortex 64 and orthotrak 6.6.4 
 software . the wilcoxon signed - rank test was performed to identify the differences in 
 spatiotemporal parameters between with and without vibration . comparison between the spatiotemporal gait parameters with and without vibration in pd 
 patients revealed that stride length and walking speed with vibration were significantly 
 increased compared with those without vibration ( p<0.05 ) . although the other parameters 
 were also improved , there were no statistically significant differences ( table 1table 1 . comparison of spatiotemporal parameters between with and without vibration in 
 patients with pdvariablewithout vibrationwith vibrationcadence ( steps / min)110.2 ( 9.6)111.6 ( 10.4)stride length ( cm)110.0 ( 15.1)114.0 ( 14.5 ) * step length ( cm)55.7 ( 7.3)58.1 ( 6.9)step width ( cm)11.5 ( 1.8)10.9 ( 1.6)walking speed ( cm / sec)101.7 ( 15.7)107.1 ( 17.3 ) * single support time ( % cycle)61.6 ( 1.8)60.5 ( 1.8)double support time ( % cycle)11.7 ( 3.0)11.1 ( 1.4)*significant difference between with and without vibration ( p<0.05 ) ) . * significant difference between with and without vibration ( p<0.05 ) pd is a progressive degenerative neuronal disease occurring because of a deficiency in the 
 dopaminergic neurons in the basal ganglia . patients with pd show movement impairment 
 symptoms such as bradykinesia , tremor , rigidity , and impaired balance18 , and these symptoms cause changes in their gaits . many 
 studies on pd patients spatiotemporal gait variables have reported that their gait patterns 
 showed a short stride length and low walking speed3 , 
 19 , 20 . vibration stimuli act as powerful proprioceptive stimuli that strongly affect motion 
 perception in patients with neurological disorders15 and , in particular , can cause changes in the motor control patterns 
 of patients with damage to their basal ganglia21 . because the basal ganglia serve as a motor control function in 
 making sequential movements , if they are not properly controlled , movements will become 
 slower and muscle activities will decrease22 . muscle stimuli overcome the suppression of the thalamus , which 
 plays an important role as a gateway and acts as an integration between the cerebral cortex 
 and subcortical signals , although only for a short time , and induce thalamocortical 
 activation , thereby improving visual perception and processing speed23 . in this study , when vibration stimuli were applied to improve the gaits of patients with 
 pd , their stride lengths and walking speeds significantly increased . given this , application 
 of the vibration stimuli to patients with pd having damaged basal ganglia seemed to cause 
 the patients motor control patterns to improve , thus improving the gait patterns of the 
 patients who had shown short stride lengths and low walking speeds . previous studies also reported that when feedback was not properly provided , movements 
 decreased gradually24 . as feedback , 
 either external information in the form of visual or auditory cues known to improve motor 
 performance and motor learning or vibration stimuli that stimulate proprioception to improve 
 motor perception are used . rubinstein et al.10 noted that visual cues were one of most effective methods for 
 stride length adjustment , and lim et al.1 
 stated that the application of auditory cues was effective for improving walking speed . vibration stimuli that brought about increases in pd patients stride lengths and walking 
 speeds are an effective method , like visual or auditory cues , which are known to be an 
 effective method for improving gait in patients with pd . therefore , vibration stimuli can be 
 said to be a type of feedback suitable for gait training or research intended to improve the 
 gait of patients with pd . because this study was conducted in patients with pd at levels 1.52.5 of hoehn and yahr s 
 scale , the results of this study can not be generalized to all patients with pd ; however , 
 they do suggest that application of vibration stimuli to the lower extremities can help 
 functional ability during gait in patients with parkinson s disease .