swallowing is a series of coordinated processes in which food boluses move from the mouth 
 to the stomach .
the 
 normal process of swallowing includes the oral preparatory phase in which food is chewed ; 
 the oral phase in which food is moved to the rear of the oral cavity and swallowing starts ; 
 the pharyngeal phase in which food is quickly moved through the pharynx to the esophagus ; 
 and the esophageal phase in which food is moved down the esophagus to the stomach1 .
if problems exist in the nerves or muscles 
 involved in this process , a person can not swallow food safely .
thus , it is important to 
 determine the causes of swallowing problems by stage and provide proper treatment to help 
 patients with dysphagia recover their swallowing function .
the pharyngeal phase in particular is involuntary , and since the airway and esophagus are 
 closely located each other , it is very important that the pharyngeal muscles operate 
 normally to prevent food boluses from entering the airway .
if problems occur with 
 coordination of the swallowing muscles in the pharyngeal stage , food can get through the 
 airway and cause serious complications such as suffocation or aspiration pneumonia .
dysphagia can be caused by various 
 diseases that can affect the nerves or muscles ; swallowing problems in the pharyngeal phase 
 in particular are frequently caused by damage to the neurological system such as stroke1 .
dysphagia affects a reported 4070% of 
 acute stroke patients2 , 3 and becomes a direct cause of malnutrition , dehydration , and 
 pneumonia .
in particular , since stroke patients are at high risk of aspiration or 
 penetration , both of which involve the passage of food into the airway due to swallowing 
 problems in the pharyngeal phase , it is critical that they obtain swallowing treatments as 
 soon as dysphagia is discovered4 .
treatment strategies for dysphagia in the oral cavity and pharynx are largely divided into 
 feeding techniques and swallowing therapy , the latter of which induces swallowing and 
 enhances the pharyngeal phase .
of these two strategies , swallowing therapy includes 
 techniques to prolong pharyngeal swallowing , enhances pharyngeal transit time , and 
 facilitates neuromuscular activities related to swallowing ; traditionally , it includes 
 compensatory approaches such as posture changes and maneuvers that improve function by 
 strengthening weak swallowing muscles1 .
neuromuscular electrical stimulation ( nmes ) , which induces the functional recovery of 
 swallowing using electrical stimulation on paralyzed cervical muscles , is frequently used in 
 swallowing treatment . a non - invasive treatment , nmes has the advantage of being easier to 
 apply than traditional treatment techniques such as compensatory approach and can be 
 effectively used for patients with damaged cognitive function for whom compensatory 
 treatment is difficult to apply5 .
nevertheless , the effectiveness of nmes in the rehabilitation of swallowing remains 
 controversial . while there are reports that nmes is significantly more effective in 
 treatment than tactile stimulation treatment or compensatory treatment techniques5 , 6 , 
 there are
also reports that nmes has no significant effect on the recovery of swallowing 
 function7 .
in addition , in retrospective 
 studies , its treatment effect was significant only in mild and moderate dysphasia8 .
to date , although domestic studies on dysphagia have mainly focused on its characteristics , 
 only a few studies have compared the treatment effect of nmes using temperature - tactile 
 stimulation , which is mainly used in clinical circumstances9 .
this study compared nmes and thermal tactile oral stimulation ( ttos ) , a traditional 
 swallowing recovery treatment , in patients with sub - acute dysphagia caused by stroke .
subjects of the present study were 55 patients diagnosed with dysphagia caused by stroke in 
 the rehabilitation departments of three general hospitals in seoul and inchon between 
 september 2014 and january 2015 who agreed to participate in this study after understanding 
 its contents .
this study was approved by the institutional review board of n university and 
 was conducted in accordance with the ethical standards of the declaration of helsinki . as 
 the minimum number of samples calculated based on power analysis was 53 with a significance 
 level ( )= 0.05 , effect size 0.5 , and power of test ( 1-)= 0.95 on the standard of 
 t - distribution , the number of samples of this study was appropriate .
the standards of 
 selection for the subjects of this study were as follows : < 6 months had passed since the 
 dysphagia diagnosis was made ; mild or moderate dysphasia ; no mental illness such as 
 depression ; fourth , no nasogastric tube ; fifth ; and no cognitive disorder > 24 points on 
 the korean mini - mental status exam .
all participants were randomly assigned into the nmes group ( n=27 ) or ttos group ( n=28 ) 
 using the table of random numbers .
subject characteristics are presented in table 1table 1.patient characteristics prior to the studyvariablenmes ( n=27)ttos ( n=18)gender male1716female1012age ( years)65.2  7.767.5  8.3duration of dysphagia ( months)4.5  1.1 4.8  1.2vfs ( score)26.1  13.125.5  11.5*p<0.05 , mean  sd .
nmes : neuromuscular electrical stimulation ; ttos : thermal 
 tactile oral stimulation ; functional dysphagia scale based on videofluoroscopic 
 studies ( vfs ) . *
nmes : neuromuscular electrical stimulation ; ttos : thermal 
 tactile oral stimulation ; functional dysphagia scale based on videofluoroscopic 
 studies ( vfs ) the nmes group received 30 minutes of stimulation per day 5 days per week for 3 weeks by a 
 swallowing therapist with vitalstim certification using vitalstim ( ap2116 ; djo 
 company , usa ) for a total of 15 treatments . referring to freed et al .
, the electrodes were 
 attached to the mylohyoid and thyrohyoid muscles , the frequency of vibration was set at 
 80  hz with a width of 300  ms , and the wave pattern was bi - phasic5 .
the electric current intensity started at 2.5 ma and , set 
 at a comfortable level for the patients by increases in 2.5-ma increments , and had a maximum 
 of 20.0 ma .
the ttos group repeated the 30-minute stimulation on the anterior faucial arch with an ice 
 stick to facilitate pharyngeal swallowing each day 5 days per week for 3 weeks .
the 
 treatment consisted of rubbing the anterior faucial arch up and down 5 times , inducing dry 
 swallowing , and repeating this method for 30 minutes .
swallowing recovery was verified by a medical doctor of rehabilitation medicine who did not 
 participate in the study using a videofluoroscopic swallowing study ( vfss ) and functional 
 dysphagia scale based on videofluoroscopic studies ( vfs)10 . for vfss ,
this study used multistar top ( siemens , erlangen , 
 germany ) and analyzed video data with virtualdub v1.10.2 ( virtualdub , korea ) which is 
 capable of analyzing 30 frames per second .
vfs is a scale that is used to identify overall swallowing problems such as aspiration 
 observed in vfss and consists of a total of 100 points .
when vfs test was developed , its sensitivity was 
 8182% and specificity was 70.792%10 .
for the analysis , a 
 preliminary homogeneity test was first conducted with an independent sample t - test or 
  test , while a pre - post efficiency test was conducted using a paired - sample 
 t - test .
chicago , il , usa ) was used for the analysis , and the 
 significance level was 0.05 .
in the test on homogeneity of age , vfs and outbreak duration of the nmes and ttos groups 
 with independent t - test and chi - square test , there was no significant difference in all 
 items ( table 1 ) .
the analysis of pre - post values of vfs of the nmes and ttos groups using a paired t - test 
 revealed no significant difference between the two groups despite both having decreased mean 
 vfs values after treatment ( table 2table 2.vfs results of nmes and ttosvfsnmes ( n=27)ttos ( n=18)pre - test26.1  13.125.5  11.5post - test14.3 
vfs : videofluoroscopic study ; nmes : neuromuscular electrical stimulation ; 
 ttos : thermal tactile oral stimulation ) . * p<0.05 .
vfs : videofluoroscopic study ; nmes : neuromuscular electrical stimulation ; 
 ttos : thermal tactile oral stimulation
the purpose of treating dysphagia in stroke patients is to reduce the risk of aspiration 
 and enhance their ability to swallow food safely . both treatment methods tested here 
 significantly enhanced swallowing function .
multiple studies have reported that nmes 
 enhanced swallowing function6 , 9 , 11 , perhaps more 
 effectively than ttos5 , in the pharyngeal 
 phase9 and enhanced function in the oral 
 phase12 . in particular , freed et al . 
 recommended using nmes with complementary treatment and ttos since they have limited effect 
 in strengthening the swallowing muscles and enhancing coordination5 .
as in these preceding studies , 3-week nmes treatment in this study effectively enhanced 
 swallowing function .
nmes is a treatment method that recovers muscle function by emitting 
 minute electricity on the skin , enhances and the larynx lifting motion , and ultimately 
 recovers swallowing function13 .
thus , it 
 is expected that applying nmes to patients with sub - acute dysphagia caused by stroke can 
 enhance their swallowing function .
the second important discovery of this study was that the effect of nmes treatment on 
 patients with sub - acute dysphagia did not have any significant difference from that of ttos . 

although treatments for dysphagia differ depending on its cause , complementary treatment , 
 ttos , and electric stimulation treatment are performed .
unlike complementary treatment and 
 ttos , which are covered by health insurance , nmes is excluded from coverage , making it 
 expensive .
nevertheless , nmes treatment is not merely frequently conducted for sub - acute 
 dysphagia but is performed by 72.3% of swallowing treatment experts14 , 15 .
therefore , it 
 is necessary to prescribe guidelines for swallowing treatment considering the economic 
 difficulties of patients with dysphagia ; accordingly , future comparisons of the 
 effectiveness and economic considerations of various swallowing treatments are required .
first , the treatment period was only 3 weeks 
 long , so future studies are required to investigate the effect of swallowing rehabilitation 
 based on treatment duration .
second , since the subjects were all diagnosed with sub - acute 
 dysphagia , the study results can not be generalized for all types of dysphagia .
thus , caution 
 should be taken in the interpretation of the study results . in this study , both nmes and ttos significantly enhanced the swallowing function of 
 patients with sub - acute dysphagia . to verify the effectiveness of nmes , future follow - up 
 studies of patients with chronic dysphagia are required .
 [ purpose ] the effectiveness of neuromuscular electrical stimulation in the rehabilitation 
 of swallowing remains controversial . this study compared the effectiveness of 
 neuromuscular electrical stimulation and thermal tactile oral stimulation , a traditional 
 swallowing recovery treatment , in patients with sub - acute dysphagia caused by stroke . 
 
 [ subjects and methods ] subjects of the present study were 55 patients diagnosed with 
 dysphagia caused by stroke . 
 this study had a nonequivalent control group pretest - posttest 
 design . 
 [ results ] analysis of pre - post values of videofluoroscopic studies of the 
 neuromuscular electrical stimulation and thermal tactile oral stimulation groups using a 
 paired t - test showed no significant difference between the two groups despite both having 
 decreased mean values of the videofluoroscopic studies after treatment . 
 [ conclusion ] this 
 study s findings show that both neuromuscular electrical stimulation and thermal tactile 
 oral stimulation significantly enhanced the swallowing function of patients with sub - acute 
 dysphagia . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION