Exploratory Investigation of the Effects of Tactile Stimulation Using Air Pressure at the Auricular Vagus Nerve on Heart Rate Variability

Objective@#To explore the effects of tactile stimulation using air pressure at the auricular branch of the vagus nerve on autonomic activity in healthy individuals. @*Methods@#Three types of tactile stimulation were used in this study: continuous low-amplitude, continuous high-amplitude, and pulsed airflow. The tactile stimulations were provided to the cymba concha to investigate autonomic activity in 22 healthy participants. The mean heart rate (HR) and parameters of HR variability, including the standard deviation of R-R intervals (SDNN) and root mean square of successive R-R interval differences (RMSSD) were compared at baseline, stimulation, and recovery periods. @*Results@#Two-way repeated measures ANOVA indicated a significant main effect of time on HR (p=0.001), SDNN (p=0.003), and RMSSD (p<0.001). These parameters showed significant differences between baseline and stimulation periods and baseline and recovery periods in the post-hoc analyses. There were no significant differences in the changes induced by stimulation type and the interaction between time and stimulation type for all parameters. One-way repeated measures ANOVA showed that HR, SDNN, and RMSSD did not differ significantly among the three time periods during sham stimulation. @*Conclusion@#Parasympathetic activity can be enhanced by auricular tactile stimulation using air pressure, targeting the cymba concha. Further studies are warranted to investigate the optimal stimulation parameters for potential clinical significance.

Clinical Practice Guidelines for Oropharyngeal Dysphagia / 대한연하장애학회지

Objective@#Dysphagia is a common clinical condition characterized by difficulty in swallowing. It is sub-classified into oropharyngeal dysphagia, which refers to problems in the mouth and pharynx, and esophageal dysphagia, which refers to problems in the esophageal body and esophagogastric junction. Dysphagia can have a significant negative impact one’s physical health and quality of life as its severity increases. Therefore, proper assessment and management of dysphagia are critical for improving swallowing function and preventing complications. Thus a guideline was developed to provide evidence-based recommendations for assessment and management in patients with dysphagia. @*Methods@#Nineteen key questions on dysphagia were developed. These questions dealt with various aspects of problems related to dysphagia, including assessment, management, and complications. A literature search for relevant articles was conducted using Pubmed, Embase, the Cochrane Library, and one domestic database of KoreaMed, until April 2021. The level of evidence and recommendation grade were established according to the Grading of Recommendation Assessment, Development and Evaluation methodology. @*Results@#Early screening and assessment of videofluoroscopic swallowing were recommended for assessing the presence of dysphagia. Therapeutic methods, such as tongue and pharyngeal muscle strengthening exercises and neuromuscular electrical stimulation with swallowing therapy, were effective in improving swallowing function and quality of life in patients with dysphagia. Nutritional intervention and an oral care program were also recommended. @*Conclusion@#This guideline presents recommendations for the assessment and management of patients with oropharyngeal dysphagia, including rehabilitative strategies.

Clinical and Swallowing Characteristics Related With Respiratory Infection in Parkinsonism Patients

Objective@#To investigate the clinical and swallowing characteristics related to respiratory infection in patients with parkinsonism. @*Methods@#One hundred and forty-two patients with parkinsonism who underwent videofluoroscopic swallowing studies (VFSS) were enrolled in this study. The initial clinical and VFSS characteristics were compared between patients with and without a history of respiratory infection in the past year. A multivariate logistic regression model was applied to identify clinical and swallowing characteristics related to respiratory infections. @*Results@#Patients with respiratory infections were older (74.75±10.20 years vs. 70.70±8.83 years, p=0.037), had a higher Hoehn and Yahr (H&Y) stage (stage IV–V, 67.9% vs. 49.1%; p=0.047), and were more likely to have a diagnosis of idiopathic Parkinson’s disease (IPD) (67.9% vs. 41.2%, p=0.011) than those without respiratory infections. Among VFSS findings, bolus formation, premature bolus loss, oral transit time, pyriform sinus residues, pharyngeal wall coatings, and penetration/aspiration were significantly worse in patients with respiratory infections (p<0.05). Regarding clinical characteristics, higher H&Y stage (odds ratio [OR], 3.174; 95% confidence interval [CI], 1.226–8.216; p=0.017) and diagnosis of IPD (OR, 0.280, 95% CI, 0.111–0.706; p=0.007) were significantly related to respiratory infections in the multivariate analysis. Among VFSS findings, pyriform sinus residue (OR, 14.615; 95% CI, 2.257–94.623; p=0.005) and premature bolus loss (OR, 5.151; 95% CI, 1.047–25.338; p=0.044) were also significantly associated with respiratory infection. @*Conclusion@#This study suggests that disease severity, diagnosis, pyriform sinus residue, and premature bolus loss observed in VFSS are associated with respiratory infection in patients with parkinsonism.

Associated Factors on Quality of Life in Patients with Parkinson's Disease

The objective of this study is to investigate the clinical and demographic factors that influence the quality of life in patients with Parkinson's disease (PD). This is a crosssectional observational study of 47 patients in 2 hospitals with PD. All participants were asked to complete a disease-specific quality of life (QoL) questionnaire (PDQ-39). We gave a structured questionnaire interview and did a complete neurological examination on the same day. Additionally, we measured depression and dependency with the Geriatric Depression Scale-Short Form (GDS-SF) and the Korean version of the Modified Barthel Index (K-MBI).The PDQ-39 had a significant relationship with each motor part of the Unified Parkinson's Disease Rating Scale, the Korean Mini-Mental State Examination (K-MMSE), the GDS-SF, and the K-MBI (p < 0.05). The factors that independently contributed to the PDQ-39 scores were K-MMSE, GDS-SF, and K-MBI (p < 0.05). Factors having the greatest influence on the PDQ-39 were K-MBI, K-MMSE, and GDS-SF in that order. In addition, the mobility item in the K-MBI was independently a significant relating factor in the PDQ-39 (p < 0.05). These results demonstrated that dependency, especially with the mobility issue, was the greatest influence on the QoL in patients with PD.

Changes in Epidemiological Trends and Rehabilitation Usage in Neurological Diseases in Korea:Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by typical motor symptoms such as resting tremor, bradykinesia, and rigidity, as well as non-motor manifestations, including psychiatric symptoms, autonomic dysfunction, and cognitive impairment. These symptoms induce a marked impact on functional independence in daily activities and quality of life in PD patients. Recent guidelines recommend adequate rehabilitation education and treatment from the early stages of PD, and rehabilitation has become part of standard care for PD. In Korea, the number of patients with PD has more than tripled over 15 years, from 39,265 in 2004 to 125,607 in 2019. However, the rehabilitation usage of PD patients has not changed remarkably, and it remains suboptimal in Korea compared to several developed countries, which have advanced and disseminated guidelines and implemented specialized care delivery systems for PD over the past 20 years. Additional efforts are warranted to provide adequate rehabilitation therapies for PD patients in Korea.

Reliability of Suprahyoid and Infrahyoid Electromyographic Measurements during Swallowing in Healthy Subjects / 대한연하장애학회지

Objective@#To evaluate the reliability of suprahyoid and infrahyoid electromyography (EMG) measurement during swallowing. @*Methods@#In all, 10 healthy volunteers were evaluated for the following surface EMG (sEMG) parameters in the suprahyoid and infrahyoid muscles during swallowing: onset latency, offset latency, duration, peak latency, maximal amplitude during swallowing, and the area under curve (AUC) of the rectified EMG signal. The sEMG was recorded while the participants swallowed five times each of the four fluid volumes (saliva, 2 ml, 5 ml, and 20 ml of water), totaling to 20 swallows. Moreover, the intra-participant variability per parameter was evaluated using the coefficient of variation (CV). @*Results@#Suprahyoid muscles were activated 0.095 s (95% CI, 0.062-0.128) earlier than the infrahyoid muscles.Maximal amplitudes during the 20 ml swallow were 17.484 (−1.543-36.512) and 13.490 (1.254-25.727) μV higher than values obtained during the 2 ml swallow in the suprahyoid and infrahyoid muscles, respectively. Furthermore, the AUC of the rectified EMG signal increased with the volume of swallow in both muscle groups (P=0.003, suprahyoid; P＜0.002, infrahyoid). The intra-individual variabilities of offset latency, duration, and maximal amplitude were relatively low (＜30% CV) in both muscle groups with respect to other parameters. The assessment of each parameter using EMG was highly reliable, with an intraclass correlation coefficient of ＞0.8. @*Conclusion@#Among the variable sEMG parameters assessed, the offset latency, duration, and maximal amplitude were the least variable. Although reliability on the rater side showed good results, the swallow-to-swallow variability of the parameters need to be considered in swallowing studies using sEMG.

Reliability of Suprahyoid and Infrahyoid Electromyographic Measurements during Swallowing in Healthy Subjects / 대한연하장애학회지

Objective@#To evaluate the reliability of suprahyoid and infrahyoid electromyography (EMG) measurement during swallowing. @*Methods@#In all, 10 healthy volunteers were evaluated for the following surface EMG (sEMG) parameters in the suprahyoid and infrahyoid muscles during swallowing: onset latency, offset latency, duration, peak latency, maximal amplitude during swallowing, and the area under curve (AUC) of the rectified EMG signal. The sEMG was recorded while the participants swallowed five times each of the four fluid volumes (saliva, 2 ml, 5 ml, and 20 ml of water), totaling to 20 swallows. Moreover, the intra-participant variability per parameter was evaluated using the coefficient of variation (CV). @*Results@#Suprahyoid muscles were activated 0.095 s (95% CI, 0.062-0.128) earlier than the infrahyoid muscles.Maximal amplitudes during the 20 ml swallow were 17.484 (−1.543-36.512) and 13.490 (1.254-25.727) μV higher than values obtained during the 2 ml swallow in the suprahyoid and infrahyoid muscles, respectively. Furthermore, the AUC of the rectified EMG signal increased with the volume of swallow in both muscle groups (P=0.003, suprahyoid; P＜0.002, infrahyoid). The intra-individual variabilities of offset latency, duration, and maximal amplitude were relatively low (＜30% CV) in both muscle groups with respect to other parameters. The assessment of each parameter using EMG was highly reliable, with an intraclass correlation coefficient of ＞0.8. @*Conclusion@#Among the variable sEMG parameters assessed, the offset latency, duration, and maximal amplitude were the least variable. Although reliability on the rater side showed good results, the swallow-to-swallow variability of the parameters need to be considered in swallowing studies using sEMG.

Kinetic Modeling of the Hyoid Movement During Swallowing and the Comparison with Surface Electromyographic Activity: A Preliminary Study / 대한연하장애학회지

Objective@#The purpose of this study was to understand the mechanism of normal hyoid movement during swallowing by calculating the activity of each muscle involved in the hyoid movement and propose a new kinetic modeling of hyoid movement using videofluoroscopy images. @*Methods@#Eight healthy volunteers with an average age of 56.8 swallowed 2-ml of diluted barium under videofluoroscopy. A video image was digitized to analyze the movement of the hyoid bone. The activity of the muscles acting on the hyoid bone was calculated from the movement of the hyoid bone using kinetic modeling. A surface electromyogram was measured simultaneously with videofluoroscopy, and the muscle force calculated by kinetic modeling was compared with the muscle force measured by surface EMG. @*Results@#The muscles acting on the hyoid bone were divided into three groups according to the direction of force and analyzed. The contraction of the retractor muscle group was observed as a median of 433 ms (95% CI 264-602, P=0.012) earlier than the contraction of protractor muscle group in all subjects. Generally, the peak activity of each muscle group was observed in the order of retractor (0 ms), protractor (592 ms, 95% CI 429-755), and depressor (717 ms, 95% CI 535-899) muscle group. The contraction of the protractor muscle measured by surface electromyography showed an earlier onset latency with a median of 82 2 ms (95% CI 615-102 9, P=0.012 ) compared to the contraction of the protractor muscle calculated by kinetic modeling. @*Conclusion@#Kinetic modeling reflects the pattern of contraction in the order of retractor, protractor, depressor muscle groups, as previously known. And it was possible to evaluate the activity of the retractor muscle, which is difficult to evaluate by electromyogram.

Correlation between Salivary Mucin Concentration and Viscosity -An Exploratory Study in Healthy People / 대한연하장애학회지

Objective@#To analyze the rheological and biochemical properties of saliva in healthy adults. @*Methods@#The subjects were seven healthy young adults (20-39 years). The whole saliva was collected by the spitting method between 9:00 am and 12:00 am. Unstimulated saliva was collected first, which was followed by the collection of stimulated saliva using citric acid was collected. The viscosity was measured using a capillary viscometer to examine the rheological properties. The MUC5B concentration was analyzed using an enzyme-linked immunosorbent assay (ELISA) for the biochemical properties. @*Results@#Ten and five minutes were required on average for unstimulated saliva and stimulated saliva, respectively, to collect the minimum amount needed for analysis (8 ml). The flow rate increased from 1.037±0.323 ml/min to 1.823± 0.660 ml/min after stimulation (P=0.018). Citric acid stimulation also increased the MUC5B concentration in the saliva from 3.706±3.575 μg/ml to 6.928±2.03 μg/ml (P=0.028). The viscosity of saliva, however, did not show a significant difference between with (1.1±0.164 cSt) or without (1.019±0.08 cSt) stimulation (P=0.128). A positive correlation was observed between the flow rate and MUC5B concentration (Spearman’s rho=0.547, P=0.043). On the other hand, there was no significant correlation between the MUC5B concentration and viscosity both in the unstimulated and stimulated saliva (P=0.939 and 0.819, respectively). @*Conclusion@#No significant correlation was observed between the MUC5B concentration and viscosity. Considering the time required to collect samples, an analysis of the stimulated saliva appears feasible in various research settings.The feasibility of these analysis methods should be examined in a patient population.

Neuroprotective Effect of Chronic Intracranial Toxoplasma gondii Infection in a Mouse Cerebral Ischemia Model

Toxoplasma gondii is an obligate intracellular protozoan parasite that can invade various organs in the host body, including the central nervous system. Chronic intracranial T. gondii is known to be associated with neuroprotection against neurodegenerative diseases through interaction with host brain cells in various ways. The present study investigated the neuroprotective effects of chronic T. gondii infection in mice with cerebral ischemia experimentally produced by middle cerebral artery occlusion (MCAO) surgery. The neurobehavioral effects of cerebral ischemia were assessed by measurement of Garcia score and Rotarod behavior tests. The volume of brain ischemia was measured by triphenyltetrazolium chloride staining. The expression levels of related genes and proteins were determined. After cerebral ischemia, corrected infarction volume was significantly reduced in T. gondii infected mice, and their neurobehavioral function was significantly better than that of the uninfection control group. Chronic T. gondii infection induced the expression of hypoxia-inducible factor 1-alpha (HIF-1α) in the brain before MCAO. T. gondii infection also increased the expression of vascular endothelial growth factor after the cerebral ischemia. It is suggested that chronic intracerebral infection of T. gondii may be a potential preconditioning strategy to reduce neural deficits associated with cerebral ischemia and induce brain ischemic tolerance through the regulation of HIF-1α expression.

Epiglottic Retroflexion is a Key Indicator of Functional Recovery of Post-stroke Dysphagia

Objective@#To evaluate the longitudinal changes of swallowing kinematics based on videofluoroscopic swallowing studies (VFSSs) in subacute stroke patients grouped according to the method of dietary intake. @*Methods@#Sixty-nine subacute stroke patients who had taken at least 2 successive VFSSs were included. Subjects were allocated into 3 groups according to the degree of swallowing function recovery—not improved group (tube feeding recommended to patients at both studies), improved group (tube feedings recommended initially to patients and oral feeding recommended at follow-up study), and well-maintained group (oral feeding at both studies recommended to patients). Initial VFSS was performed during the subacute stage of stroke, 1 to 12 weeks after the onset of stroke, and follow-up VFSS was performed at least once. Kinematic variables were calculated by two-dimensional motion analysis of multiple structures, including the hyoid bone, epiglottis, and vocal cord. Changes of kinematic variables were analyzed in serial VFSSs. @*Results@#At the initial VFSS, the well-maintained group showed significantly larger angles of epiglottic folding than the not improved group, while at the follow-up VFSS, the improved and the well-maintained groups showed significantly larger epiglottic folding angles than the not improved group. The distribution of epiglottic folding angles was in a dichotomous pattern, and each cluster was related to the swallowing function. @*Conclusion@#This study showed that improved epiglottic folding angles are associated with the recovery of the swallowing process and suitability for oral feeding among various kinematic variables in subacute stroke patients.

Temporarily Aggravated Dysphagia Following Osteophytectomy and Fixation in a Patient with Cervical Osteophyte / 대한연하장애학회지

An anterior cervical osteophyte is one of the causes of dysphagia. Surgical treatment is one of the treatment options available, and previous studies have suggested that it is an immediate and effective treatment. This paper reports a case of temporarily aggravated dysphagia after surgical treatment in a patient with anterior cervical osteophyte. A 75-year-old male complained of dysphagia for one year. A videofluoroscopic swallowing study (VFSS) revealed anterior cervical osteophytes at the C3 and C4 level, which resulted in decreased epiglottic folding and partial obstruction of the bolus passage. After he underwent osteophytectomy and anterior fixation, the post-operative VFSS showed an aggravation of dysphagia with prevertebral soft tissue edema. The major cause of dysphagia was attributed to the limitation of movement of the posterior pharyngeal wall and upper esophageal sphincter due to the increased prevertebral soft tissue thickness. In conclusion, surgery should be considered when a severe dysphagia is persistent after adequate conservative treatment in patients with dysphagia due to anterior cervical osteophytes, and patients at high risk of postoperative dysphagia might require swallowing rehabilitation.

Proportion of Aspiration Pneumonia Cases Among Patients With Community-Acquired Pneumonia: A Single-Center Study in Korea

OBJECTIVE: To investigate the proportion of aspiration pneumonia cases among patients with community-acquired pneumonia in Korea. METHODS: This retrospective study included patients with community-acquired pneumonia who had been admitted to the emergency department of a university-affiliated tertiary hospital in Gyeonggi Province, Korea between January 1, 2016 and December 31, 2016. Among these patients, those with aspiration pneumonia were identified using ICD-10 codes (J69.*). Patients with recurrent pneumonia were excluded, as were those who were immunocompromised. The proportion of cases of aspiration pneumonia was calculated, and the characteristics and clinical outcomes of patients with aspiration pneumonia and non-aspiration pneumonia were compared. RESULTS: The proportion of aspiration pneumonia cases among patients with community-acquired pneumonia was 14.2%. Patients with aspiration pneumonia were significantly more likely to be older (p<0.001) and male (p<0.001), and to have a higher confusion, uremia, respiratory rate, blood pressure, and age ≥65 years (CURB-65) score (p<0.001) as compared to patients with non-aspiration pneumonia. They were also more likely to require admission to the intensive care unit (p<0.001) and a longer hospital stay (p<0.001). CONCLUSION: Aspiration pneumonia accounts for 14.2% of all cases of community-acquired pneumonia in Korea. These data may contribute to the establishment of healthcare strategies for managing aspiration pneumonia among Korean adults.

Assessment of Dysarthria Using One-Word Speech Recognition with Hidden Markov Models

BACKGROUND: The gold standard in dysarthria assessment involves subjective analysis by a speech–language pathologist (SLP). We aimed to investigate the feasibility of dysarthria assessment using automatic speech recognition. METHODS: We developed an automatic speech recognition based software to assess dysarthria severity using hidden Markov models (HMMs). Word-specific HMMs were trained using the utterances from one hundred healthy individuals. Twenty-eight patients with dysarthria caused by neurological disorders, including stroke, traumatic brain injury, and Parkinson's disease were participated and their utterances were recorded. The utterances of 37 words from the Assessment of Phonology and Articulation for Children test were recorded in a quiet control booth in both groups. Patients were asked to repeat the recordings for evaluating the test–retest reliability. Patients' utterances were evaluated by two experienced SLPs, and the consonant production accuracy was calculated as a measure of dysarthria severity. The trained HMMs were also employed to evaluate the patients' utterances by calculating the averaged log likelihood (aLL) as the fitness of the spoken word to the word-specific HMM. RESULTS: The consonant production accuracy reported by the SLPs strongly correlated (r = 0.808) with the aLL, and the aLL showed excellent test–retest reliability (intraclass correlation coefficient, 0.964). CONCLUSION: This leads to the conclusion that dysarthria assessment using a one-word speech recognition system based on word-specific HMMs is feasible in neurological disorders.

Influence of Supraglottic Swallow on Swallowing Kinematics: Comparison between the Young and the Elderly / 대한연하장애학회지

OBJECTIVE: This study was conducted to evaluate the influence of supraglottic swallowing maneuver on swallowing kinematics using kinematic analysis of a videofluoroscopic swallowing study (VFSS). METHOD: Twenty healthy volunteers (10 in a young group ( < 40 years) and 10 in an elderly group (≥60 years)), participated in this study. After structured instruction by a skilled physician, the subjects swallowed 5 ml of diluted barium in the neutral position without any swallowing maneuvers, as well as with supraglottic swallow maneuver under digital videofluoroscopy, three times each. Kinematic analysis was conducted by digitization of video files for movements of hyolaryngeal structures, including the hyoid bone, larynx, arytenoid, and epiglottis. We measured the maximum displacements and velocities of the hyolaryngeal structures during swallowing. RESULT: The most remarkable change in supraglottic swallow was the maximum vertical displacement (mm) of the hyoid bone during swallowing in both groups (11.5±3.34–19.7±6.88 in the young group, P=0.009; 13.4±2.13–22.8±5.35 in the elderly group, P < 0.001). For velocity variables, patterns of change differed between the young and elderly groups. In the young group, the maximum vertical velocities of the larynx and arytenoid were decreased (P < 0.05), but in the elderly group, the maximum 2D velocity of hyoid bone, maximum horizontal and 2D velocity of the larynx and maximum horizontal velocity of the arytenoid were increased (P < 0.05). There were no significant differences in changes between the young and elderly groups. CONCLUSION: This study showed that supraglottic swallow could affect hyolaryngeal movements, particularly vertical hyoid movement, during swallowing. Beneficial kinematic changes in supraglottic swallow were more pronounced in the elderly group. Therefore, supraglottic swallow may contribute to swallowing improvement by enhancing hyolaryngeal movements during swallowing, in addition to laryngeal closure.

Limitation of Intraoperative Transcranial Electrical Stimulation-Motor Evoked Potential Monitoring During Brain Tumor Resection Adjacent to the Primary Motor Cortex

Transcranial electrical stimulation-motor evoked potential (TES-MEP) is a valuable intraoperative monitoring technique during brain tumor surgery. However, TES can stimulate deep subcortical areas located far from the motor cortex. There is a concern about false-negative results from the use of TES-MEP during resection of those tumors adjacent to the primary motor cortex. Our study reports three cases of TES-MEP monitoring with false-negative results due to deep axonal stimulation during brain tumor resection. Although no significant change in TES-MEP was observed during surgery, study subjects experienced muscle weakness after surgery. Deep axonal stimulation of TES could give false-negative results. Therefore, a combined method of TES-MEP and direct cortical stimulation-motor evoked potential (DCS-MEP) or direct subcortical stimulation should be considered to overcome the limitation of TES-MEP.

Medical Management for Radiation-induced Dysphagia / 대한연하장애학회지

Dysphagia after radiotherapy for head and neck cancer is a common problem that affects the nutritional status and quality of life of patients. In particular, although radiation-induced dysphagia associated with late fibroatrophy is often progressive and intractable, there have been only few studies on the therapeutic options, and preventive efforts are not performed well in clinics. This review summarizes the management of radiation-induced dysphagia and suggests possible medical treatments based on the current evidence and reported pathophysiologic mechanisms.

Normative Temporal Data of Hyolaryngeal Movements during Swallowing / 대한연하장애학회지

OBJECTIVE: This study evaluated the temporal variables of hyolaryngeal movements during normal swallowing using kinematic analysis of the video fluoroscopic swallowing study (VFSS) to present the normal cut-off values of those variables. METHODS: Seventy-five healthy volunteers (17 men, 58 women) without swallowing dysfunctions were recruited to examine the swallowing of 2-ml diluted barium by a VFSS. Kinematic analysis was conducted by digitization of video files for movements of hyolaryngeal structures, including the vocal cords, hyoid bone, and epiglottis during normal swallowing. The time points and duration of hyolaryngeal movements were measured. The time points were the start point, maximal point, and the end point of the LE (Laryngeal Elevation), HE (Hyoid Excursion), and EF (Epiglottic Folding). The durations of LE, HE, and EF were obtained by subtracting the time of the start point from the time of the maximal point. The onset time of LE was defined as the reference time point (0 sec). The upper and lower limits of the 95% confidence interval were adopted as the normal cut-off values for the temporal variables of hyolaryngeal movements after transformation to a normal distribution. If a transformation formula to a normal distribution was not found in a variable, the values of the 2.5–97.5 percentile were adopted. RESULTS: The cut-off values of the maximal and end points of the LE were 0.281 to 0.916 sec, and 0.830 to 2.205 sec, respectively. The cut-off values of the start, maximal and end points of the HE were −0.233 to 0.400 sec, 0.320 to 0.874 sec, and 0.889 to 2.055 sec, respectively. The cut-off values of the start, maximal, and end points of the EF were 0.017 to 0.483 sec, 0.364 to 1.055 sec, and 0.774 to 1.773 sec, respectively. The cut-off values of the duration of LE, HE, and EF were 0.281 to 0.916 sec, 0.258 to 0.767 sec, and 0.255 to 0.787 sec, respectively. CONCLUSION: This study presented the normal cut-off values of temporal variables of hyolaryngeal movements during normal swallowing. This study can serve as a basis for classifying and analyzing the patterns of patients with dysphagia.

Changes in Hyolaryngeal Movement During Swallowing in the Lateral Decubitus Posture

OBJECTIVE: To investigate the differences in hyolaryngeal kinematics at rest and during swallowing in the upright sitting (UP) and the lateral decubitus (LD) postures in healthy adults, and delineating any potential advantages of swallowing while in the LD posture. METHODS: Swallowing was videofluoroscopically evaluated in 20 healthy volunteers in UP and LD postures, based on the movements of hyoid bone, vocal folds, and the bolus head. Parameters included the Penetration-Aspiration Scale (PAS), horizontal and vertical displacement, horizontal and vertical initial position, horizontal and vertical peak position, time to peak position of the hyoid bone and vocal folds, and pharyngeal transit time (PTT). RESULTS: Nine participants were rated PAS 2 in the UP and 1 was rated PAS 2 in the LD (p=0.003) at least 1 out of 3 swallows each posture. The hyoid and vocal folds showed more anterior and superior peak and initial positions in the LD. In addition, swallowing resulted in greater vertical and smaller horizontal displacement of the hyoid in LD posture compared with UP. Time to peak position of the hyoid was shorter in LD. The maximal vertical and horizontal displacement of the vocal folds, and PTT were comparable between postures. CONCLUSION: The results showed that the peak and initial positions of the hyoid and larynx and the pattern of hyoid movement varied significantly depending on the body postures. This study suggests that the LD posture was one of the safe feeding postures without any increased risk compared with UP posture.

Intraoperative Monitoring of Hypoglossal Nerve Using Hypoglossal Motor Evoked Potential in Infratentorial Tumor Surgery: A Report of Two Cases

The hypoglossal nerve (CN XII) may be placed at risk during posterior fossa surgeries. The use of intraoperative monitoring (IOM), including the utilization of spontaneous and triggered electromyography (EMG), from tongue muscles innervated by CN XII has been used to reduce these risks. However, there were few reports regarding the intraoperative transcranial motor evoked potential (MEP) of hypoglossal nerve from the tongue muscles. For this reason, we report here two cases of intraoperative hypoglossal MEP monitoring in brain surgery as an indicator of hypoglossal deficits. Although the amplitude of the MEP was reduced in both patients, only in the case 1 whose MEP was disappeared demonstrated the neurological deficits of the hypoglossal nerve. Therefore, the disappearance of the hypoglossal MEP recorded from the tongue, could be considered a predictor of the postoperative hypoglossal nerve deficits.