Two Years of Experience and Methodology of Korean COVID-19 Living Clinical Practice Guideline Development

Background@#In Korea, during the early phase of the coronavirus disease 2019 (COVID-19) pandemic, we responded to the uncertainty of treatments under various conditions, consistently playing catch up with the speed of evidence updates. Therefore, there was high demand for national-level evidence-based clinical practice guidelines for clinicians in a timely manner. We developed evidence-based and updated living recommendations for clinicians through a transparent development process and multidisciplinary expert collaboration. @*Methods@#The National Evidence-based Healthcare Collaborating Agency (NECA) and the Korean Academy of Medical Sciences (KAMS) collaborated to develop trustworthy Korean living guidelines. The NECA-supported methodological sections and 8 professional medical societies of the KAMS worked with clinical experts, and 31 clinicians were involved annually. We developed a total of 35 clinical questions, including medications, respiratory/critical care, pediatric care, emergency care, diagnostic tests, and radiological examinations. @*Results@#An evidence-based search for treatments began in March 2021 and monthly updates were performed. It was expanded to other areas, and the search interval was organized by a steering committee owing to priority changes. Evidence synthesis and recommendation review was performed by researchers, and living recommendations were updated within 3–4 months. @*Conclusion@#We provided timely recommendations on living schemes and disseminated them to the public, policymakers and various stakeholders using webpages and social media.Although the output was successful, there were some limitations. The rigor of development issues, urgent timelines for public dissemination, education for new developers, and spread of several new COVID-19 variants have worked as barriers. Therefore, we must prepare systematic processes and funding for future pandemics.

First-Pass Recanalization with EmboTrap II in Acute Ischemic Stroke (FREE-AIS): A Multicenter Prospective Study

Objective@#We aimed to evaluate the efficacy of EmboTrap II in terms of first-pass recanalization and to determine whether it could yield favorable outcomes. @*Materials and Methods@#In this multicenter, prospective study, we consecutively enrolled patients who underwent mechanical thrombectomy using EmboTrap II as a front-line device. The primary outcome was the first pass effect (FPE) rate defined by modified Thrombolysis In Cerebral Infarction (mTICI) grade 2c or 3 by the first pass of EmboTrap II. In addition, modified FPE (mFPE; mTICI grade 2b–3 by the first pass of EmboTrap II), successful recanalization (final mTICI grade 2b–3), and clinical outcomes were assessed. We also analyzed the effect of FPE on a modified Rankin Scale (mRS) score of 0–2 at 3 months. @*Results@#Two hundred-ten patients (mean age ± standard deviation, 73.3 ± 11.4 years; male, 55.7%) were included. Ninetynine patients (47.1%) had FPE, and mFPE was achieved in 150 (71.4%) patients. Successful recanalization was achieved in 191 (91.0%) patients. Among them, 164 (85.9%) patients underwent successful recanalization by exclusively using EmboTrap II. The time from groin puncture to FPE was 25.0 minutes (interquartile range, 17.0–35.0 minutes). Procedure-related complications were observed in seven (3.3%) patients. Symptomatic intracranial hemorrhage developed in 14 (6.7%) patients. One hundred twenty-three (58.9% of 209 completely followed) patients had an mRS score of 0–2. Sixteen (7.7% of 209) patients died during the follow-up period. Patients who had successful recanalization with FPE were four times more likely to have an mRS score of 0–2 than those who had successful recanalization without FPE (adjusted odds ratio, 4.13;95% confidence interval, 1.59–10.8; p = 0.004). @*Conclusion@#Mechanical thrombectomy using the front-line EmboTrap II is effective and safe. In particular, FPE rates were high. Achieving FPE was important for an mRS score of 0–2, even in patients with successful recanalization.

Korean Clinical Practice Guidelines for Adverse Reactions to Intravenous Iodinate and MRI-Gadolinium Contrast Agents: Revised Clinical Consensus and Recommendations (3rd Edition, 2022)

The Korean Society of Radiology and Medical Guidelines Committee amended the existing 2016 guidelines to publish the “Korean Clinical Practice Guidelines for Adverse Reactions to Iodide Contrast for Injection and Gadolinium Contrast for MRI: The Revised Clinical Consensus and Recommendations (2022 Third Edition).” Expert members recommended and approved by the Korean Society of Radiology, the Korean Academy of Asthma, Allergy and Clinical Immunology, and the Korean Nephrology Society participated together. According to the expert consensus or systematic literature review, the description of the autoinjector and connection line for the infection control while using contrast medium, the acute adverse reaction, and renal toxicity to iodized contrast medium were modified and added. We would like to introduce the revised contents.

Dilatation of Superior Ophthalmic Vein and Visual Disturbance by Central Venous Stenosis: A Case Mimicking Cavernous Sinus Dural Arteriovenous Fistula

Central venous stenosis is a relatively common complication in hemodialysis patients; however, jugular venous reflux (JVR) and increased intracranial pressure are rare, and associated progressive visual disturbance was reported in only a few cases. Here, we report a case of JVR with visual disturbance and increased intracranial pressure. Notably, the MRI was accompanied by a dilatation of the superior ophthalmic vein, which was mistaken for a cavernous sinus dural arteriovenous fistula (CSdAVF). The patient had JVR on time-of-flight MR angiography (TOF-MRA) and severe stenosis of the left brachiocephalic vein on conventional angiography. After balloon angioplasty for central venous stenosis, he was discharged after improvement of his visual disturbance. Although JVR due to central venous stenosis and CSdAVF might show similar symptoms, treatment plans are different. Therefore, it is important to distinguish radiologically based on a thorough review of MRI and TOF-MRA and confirm the central venous stenosis on cerebral angiography for the accurate diagnosis.

Assessment of Hand Motor Function in a Non-human Primate Model of Ischemic Stroke

Ischemic stroke results from arterial occlusion and can cause irreversible brain injury. A non-human primate (NHP) model of ischemic stroke was previously developed to investigate its pathophysiology and for efficacy testing of therapeutic candidates; however, fine motor impairment remains to be well-characterized. We evaluated hand motor function in a cynomolgus monkey model of ischemic stroke. Endovascular transient middle cerebral artery occlusion (MCAO) with an angiographic microcatheter induced cerebral infarction. In vivo magnetic resonance imaging mapped and measured the ischemia-induced infarct lesion. In vivo diffusion tensor imaging (DTI) of the stroke lesion to assess the neuroplastic changes and fiber tractography demonstrated three-dimensional patterns in the corticospinal tract 12 weeks after MCAO. The hand dexterity task (HDT) was used to evaluate fine motor movement of upper extremity digits. The HDT was modified for a home cage-based training system, instead of conventional chair restraint training. The lesion was localized in the middle cerebral artery territory, including the sensorimotor cortex. Maximum infarct volume was exhibited over the first week after MCAO, which progressively inhibited ischemic core expansion, manifested by enhanced functional recovery of the affected hand over 12 weeks after MCAO. The total performance time decreased with increasing success rate for both hands on the HDT. Compensatory strategies and retrieval failure improved in the chronic phase after stroke. Our findings demonstrate the recovery of fine motor skill after stroke, and outline the behavioral characteristics and features of functional disorder of NHP stroke model, providing a basis for assessing hand motor function after stroke.

Korean Clinical Imaging Guidelines for Diagnosis of Headache Based on the 2017 Evidence-Based Clinical Imaging Guidelines

Headache is the most common cause of neurological disorders. The usefulness of imaging tests may vary depending on the patient's clinical situation. The Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency have decided to develop evidence-based guidelines for the imaging tests necessary for diagnosing patients with selected, frequently encountered types of headache. Development, working, and advisory committees were formed. Recommendation statements were derived from the adaptive development methods provided by the existing guidelines. Non-contrast head CT is recommended in patients with acute thunderclap headache due to possible subarachnoid hemorrhage (SAH), and CT angiography is recommended to confirm aneurysmal SAH. In patients with non-acute headache and normal neurological findings, radiological examination is not recommended, but head MRI is recommended to investigate the cause of secondary headache. Non-contrast head MRI is recommended for new-onset headache with neurologic abnormalities in pregnant women.

Increased CD68/TGFβ Co-expressing Microglia/Macrophages after Transient Middle Cerebral Artery Occlusion in Rhesus Monkeys

The function of microglia/macrophages after ischemic stroke is poorly understood. This study examines the role of microglia/macrophages in the focal infarct area after transient middle cerebral artery occlusion (MCAO) in rhesus monkeys. We measured infarct volume and neurological function by magnetic resonance imaging (MRI) and non-human primate stroke scale (NHPSS), respectively, to assess temporal changes following MCAO. Activated phagocytic microglia/macrophages were examined by immunohistochemistry in post-mortem brains (n=6 MCAO, n=2 controls) at 3 and 24 hours (acute stage), 2 and 4 weeks (subacute stage), and 4, and 20 months (chronic stage) following MCAO. We found that the infarct volume progressively decreased between 1 and 4 weeks following MCAO, in parallel with the neurological recovery. Greater presence of cluster of differentiation 68 (CD68)-expressing microglia/macrophages was detected in the infarct lesion in the subacute and chronic stage, compared to the acute stage. Surprisingly, 98~99% of transforming growth factor beta (TGFβ) was found colocalized with CD68-expressing cells. CD68-expressing microglia/macrophages, rather than CD206⁺ cells, may exert anti-inflammatory effects by secreting TGFβ after the subacute stage of ischemic stroke. CD68⁺ microglia/macrophages can therefore be used as a potential therapeutic target.

Does Multiphasic Contrast Enhanced Fluid Attenuated Inversion Recovery Magnetic Resonance Imaging Enhance the Detectability of Small Intracerebral Metastases?

PURPOSE@#To determine adequate timing of acquisition of contrast-enhanced fluid attenuated inversion recovery (FLAIR) by using multiphasic contrast-enhanced FLAIR magnetic resonance imaging (MRI) and to evaluate added value in detecting small intracerebral metastases 5 mm or less.@*MATERIALS AND METHODS@#Twenty-nine patients, that underwent multiphasic contrast-enhanced FLAIR MRI and contrast-enhanced T1 weighted image (T1WI) were included and total number of small intracerebral metastases was 131. Sensitivity, specificity and accuracy of lesion detection were evaluated. Contrast ratio (CR) and enhancement ratio of each lesion were compared and analyzed among each imaging sequence.@*RESULTS@#Sensitivity, specificity and accuracy of lesion detection were increased when contrast-enhanced FLAIR was added to contrast-enhanced T1WI. Area of under receiver operating characteristic curve significantly increased by addition of contrast-enhanced FLAIR than using contrast-enhanced T1WI alone (p < 0.05). CR was significantly higher in contrast-enhanced T1WI than FLAIR (p < 0.001). All of the above results were not different according to time of acquisition of contrastenhanced FLAIR.@*CONCLUSION@#There was advantage of conducting contrast-enhanced FLAIR MRI, but multiphasic contrast-enhanced FLAIR did not provide additional information for detection of small intracerebral metastases compared with single-phase FLAIR MRI.

Quantitative Analysis of Factors Affecting Cobalt Alloy Clip Artifacts in Computed Tomography

OBJECTIVE: Clip artifacts limit the visualization of intracranial structures in CT scans from patients after aneurysmal clipping with cobalt alloy clips. This study is to analyze the parameters influencing the degree of clip artifacts. METHODS: Postoperative CT scans of 60 patients with straight cobalt alloy-clipped aneurysms were analyzed for the maximal diameter of white artifacts and the angle and number of streak artifacts in axial images, and the maximal diameter of artifacts in three-dimensional (3-D) volume-rendered images. The correlation coefficient (CC) was determined between each clip artifact type and the clip blade length and clip orientation to the CT scan (angle a, lateral clip inclination in axial images; angle b, clip gradient to scan plane in lateral scout images). RESULTS: Angle b correlated negatively with white artifacts (r=-0.589, p<0.001) and positively with the angle (r=0.636, p<0.001) and number (r=0.505, p<0.001) of streak artifacts. Artifacts in 3-D images correlated with clip blade length (r=0.454, p=0.004). Multiple linear regression analysis revealed that angle b was the major parameter influencing white artifacts and the angle and number of streak artifacts in axial images (p<0.001), whereas clip blade length was a major factor in 3-D images (p=0.034). CONCLUSION: Use of a clip orientation perpendicular to the scan gantry angle decreased the amount of white artifacts and allowed better visualization of the clip site.

Changes in Effective Connectivity According to Working Memory Load: An fMRI Study of Face and Location Working Memory Tasks

OBJECTIVE: The functional strategic mechanisms in the brain during performing visuospatial working memory tasks, especially tasks with heavy load, are controversial. We conducted the functional magnetic resonance imaging (fMRI) while sixteen subjects were performing face- and location-matching n-back tasks to examine causal relations within the frontoparietal networks. METHODS: We applied a sophisticated method, the structural equation modeling (SEM), to the fMRI data. The imaging data were analyzed by extracting the task-related eigenseries using the principal component analysis (PCA) and then by applying a form of data-driven model called the automated search method. RESULTS: The SEM analyses revealed a functional shift of network connectivity from the right to the left hemisphere with increasing load in the face-matching n-back tasks while the location-matching tasks required bilateral activation. In the locating matching n-back tasks, a pattern of parallel processing was observed in the left phonological loop and the right inferior parietal regions. Furthermore, object working memory-related activities in the left hemisphere reliably contributed to performance of both the face- and location-matching 2-back tasks. CONCLUSION: Our results are consistent with previous reports in terms of demonstrating parallel and distributed information processing during performing working memory tasks with heavy loads. Our results additionally suggest a dynamic shift between the fast imagery circuit (right hemisphere) and the stable verbal circuit (left hemisphere), depending on task load.

Altered Brain Activation in Ventral Frontal-Striatal Regions Following a 16-week Pharmacotherapy in Unmedicated Obsessive-Compulsive Disorder

Recent studies have reported that cognitive inflexibility associated with impairments in a frontal-striatal circuit and parietal region is a core cognitive deficit of obsessive-compulsive disorder (OCD). However, few studies have examined progressive changes in these regions following clinical improvement in obsessive-compulsive symptoms. To determine if treatment changes the aberrant activation pattern associated with task switching in OCD, we examined the activation patterns in brain areas after treatment. The study was conducted on 10 unmedicated OCD patients and 20 matched controls using event-related functional magnetic resonance imaging. Treatment improved the clinical symptoms measured by the Yale-Brown Obsessive Compulsive Scale and behavioral flexibility indicated by the switching cost. At baseline, OCD showed significantly less activation in the dorsal and ventral frontal-striatal circuit and parietal regions under the task-switch minus task-repeat condition compared with controls. After treatment, the neural responses in the ventral frontal-striatal circuit in OCD were partially normalized, whereas the activation deficit in dorsal frontoparietal regions that mediate shifting attention or behavioral flexibility persisted. It is suggested that altered brain activation in ventral frontal-striatal regions in OCD patients is associated with their cognitive flexibility and changes in these regions may underlie the pathophysiology of OCD.

Gray Matter Changes in Patients with Pathological Gambling: A Preliminary Study Using Voxel-Based Morphometry Study

OBJECTIVES: The purpose of this study was to examine structural abnormalities of brain in patients with pathological gambling(PG) using voxel-based morphometry. METHODS: We compared gray matter(GM) volumes between 10 patients with PG and 14 age- and IQmatched healthy controls and examined the relationship of GM volumes with clinical variables in patients with PG. RESULTS: We found significant increase of GM volume in the superior, middle, and inferior frontal gyri, the midbrain, the middle temporal gyrus, the precuneus, and the fusiform gyrus of patients with PG. A significant decrease of GM volume was observed in the parahippocampal gyrus and the lingual gyrus of the patient group. In addition, GM volumes in some of these regions were positively associated with South Oaks Gambling Screen score and negatively with age of onset in patients with PG. CONCLUSION: Current findings indicate that structural abnormalities in the fronto-temporal cortex, the midbrain, and the precuneus might be involved in the pathophysiology of PG, and contribute to some of the behavioral changes observed in patients with PG.

Thalamic Volume in Schizophrenia Patients, Subjects at Ultra-High Risk for Psychosis and Controls / 신경정신의학

OBJECTIVES: To investigate the changes in thalamic volumes in subjects at ultra-high risk (UHR) for psychosis. Subjects manifest changes which are similar to but different from those found in subjects with schizophrenia, and thalamic structural changes were often reported in schizophrenic subjects. METHODS: Thalamic volumes of 29 UHR subjects, 31 subjects with schizophrenia and 29 healthy controls, were measured from their T1-weighted coronal magnetic resonance (MR) images using manual tracing. RESULTS: UHR subjects showed greater right (6.243+/-0.848 cm3) and total (12.254+/-1.532 cm3) thalamic volumes compared to healthy control subjects (right thalamic volume=5.527+/-0.715 cm3, total thalamic volume=11.058+/-1.490 cm3) or patients with schizophrenia (right thalamic volume=5.855+/-0.938 cm3, total thalamic volume=11.513+/-1.784 cm3). The difference was significant for right (F=5.837, p=0.004) and total (F=4.217, p=0.018) thalamic volumes after intracranial volume had been accounted for as a covariate in ANCOVA. However, thalamic volume of subjects with schizophrenia showed no significant difference from controls. This difference was not affected by the presence of major depressive disorder or the magnitude of psychotic symptoms. Those among the UHR subjects taking antipsychotic agents did not show enlarged thalamic volume compared to controls. CONCLUSION: Our findings suggest that the possibility of a volumetric alteration of the thalamus characteristic of the UHR state.

Depressive Symptoms and Brain Metabolite Alterations in Subjects at Ultra-high Risk for Psychosis: A Preliminary Study

OBJECTIVE: Recent neuroimaging studies have suggested that brain changes occur in subjects at ultra-high risk (UHR) for psychosis while experiencing prodromal symptoms, among which depression may increase the risk of developing a psychotic disorder. The goal of this study is to examine brain metabolite levels in the anterior cingulate cortex, the left dorsolateral prefrontal cortex and the left thalamus in subjects at UHR for psychosis and to compare brain metabolite levels between the UHR subjects with comorbid major depressive disorder and healthy controls. METHODS: Proton magnetic resonance spectroscopy was used to examine brain metabolite levels. Twenty UHR subjects and 20 age- and intelligence quotient (IQ)-matched healthy controls were included in this study. RESULTS: Overall, no significant differences were observed in any metabolite between the UHR and healthy control group. However, UHR subjects with major depressive disorder showed significantly higher myo-inositol (Ins) levels in the left thalamus, compared to the healthy control. CONCLUSION: Our results demonstrate that increased thalamic Ins level is associated with prodromal depressive symptoms. Further longitudinal follow-up studies with larger UHR sample sizes are required to investigate the function of Ins concentrations as a biomarker of vulnerability to psychosis.

Depressive Symptoms and Brain Metabolite Alterations in Subjects at Ultra-high Risk for Psychosis: A Preliminary Study

OBJECTIVE: Recent neuroimaging studies have suggested that brain changes occur in subjects at ultra-high risk (UHR) for psychosis while experiencing prodromal symptoms, among which depression may increase the risk of developing a psychotic disorder. The goal of this study is to examine brain metabolite levels in the anterior cingulate cortex, the left dorsolateral prefrontal cortex and the left thalamus in subjects at UHR for psychosis and to compare brain metabolite levels between the UHR subjects with comorbid major depressive disorder and healthy controls. METHODS: Proton magnetic resonance spectroscopy was used to examine brain metabolite levels. Twenty UHR subjects and 20 age- and intelligence quotient (IQ)-matched healthy controls were included in this study. RESULTS: Overall, no significant differences were observed in any metabolite between the UHR and healthy control group. However, UHR subjects with major depressive disorder showed significantly higher myo-inositol (Ins) levels in the left thalamus, compared to the healthy control. CONCLUSION: Our results demonstrate that increased thalamic Ins level is associated with prodromal depressive symptoms. Further longitudinal follow-up studies with larger UHR sample sizes are required to investigate the function of Ins concentrations as a biomarker of vulnerability to psychosis.

Comparison of 64 Channel 3 Dimensional Volume CT with Conventional 3D CT in the Diagnosis and Treatment of Facial Bone Fractures

PURPOSE: Facial trauma is increasing along with increasing popularity in sports, and increasing exposure to crimes or traffic accidents. Compared to the 3D CT of 1990s, the latest CT has made significant improvement thus resulting in higher accuracy of diagnosis. The objective of this study is to compare 64 channel 3 dimensional volume CT(3D VCT) with conventional 3D CT in the diagnosis and treatment of facial bone fractures. METHODS: 45 patients with facial trauma were examined by 3D VCT from Jan. 2006 to Feb. 2007. 64 channel 3D VCT which consists of 64 detectors produce axial images of 0.625 mm slice and it scans 175mm per second. These images are transformed into 3 dimensional image using software Rapidia 2.8. The axial image is reconstructed into 3 dimensional image by volume rendering method. The image is also reconstructed into coronal or sagittal image by multiplanar reformatting method. RESULTS: Contrasting to the previous 3D CT which formulates 3D images by taking axial images of 1-2mm, 64 channel 3D VCT takes 0.625mm thin axial images to obtain full images without definite step ladder appearance. 64 channel 3D VCT is effective in diagnosis of thin linear bone fracture, depth and degree of fracture deviation. CONCLUSION: In its expense and speed, 3D VCT is superior to conventional 3D CT. Owing to its ability to reconstruct full images regardless of the direction using 2 times higher resolution power and 4 times higher speed of the previous 3D CT, 3D VCT allows for accurate evaluation of the exact site and deviation of fine fractures.

A Case of Tunneled Cuffed Catheter Dysfunction Treated with Fibrin Sheath Stripping / 대한신장학회잡지

With the increasing proportion of elderly and diabetic dialysis patients, permanent dual lumen catheters are becoming popular. One of the most frequent causes for the failure of hemodialysis in CRF patients with the tunneled cuffed catheter is the catheter dysfunction. It is thought to be due to encasement of the catheter by fibrin sleeve or fibrin sheath, kinking or malposition of the catheter. Catheter dysfunction due to fibrin sheath formation could sometimes be managed by reversal of arterial and venous lines, urokinase lock or infusion, and catheter exchange. Recently percutaneous fibrin sheath stripping (PFSS) became another modality of salvaging failing tunneled cuffed catheter before attempting catheter exchange. There was no report of applying PFSS to salvage the permanent dual lumen catheter in Korea. Authors recently experienced a case of successful application of PFSS to extend the life of catheter in a CRF patients as a last resort after failure of repeated urokinase trials. It is thought that PFSS is a simple and effective procedure which extends the longevity of permanent dual lumen catheter.

Impact of Adenotonsillar Hypertrophy on Child Personality and Behavior / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Although children's personality and behavior change caused by adenotonsillar hypertrophy have been thought to significantly relate with children's growth and learning capability, it has not been substantiated by any available standarized assessment. We aim to uncover the impact of adenotonsillar hypertrophy on children's personality and behavior by K-CBCL (Korean Child Behavior Checklist) and KPI-C (Korean Personality Inventory for Children). MATERIALS AND METHOD: Children aged 5 through 15 years old, a total of 33 (M: 18 F: 15) who were scheduled for T & A (Tonsillectomy and Adenoidectomy), were studied. The control group consisted of 42 healthy children (M: 22 F: 20) of the same age. Two standard questionnaires, K-CBCL and KPI-C, were given to the parents of the children to complete and then a statistical analysis carried out by a clinical psychologist for interpretation (p<0.05, by SPSS v10.0). RESULTS: According to K-CBCL, internalizing problems and total behavior problems were of statistical significance for the patient group compared to healthy children (p<0.05). KPI-C test revealed statistical significance on ERS (ego resilience scale), ANX (anxiety), SOM (somatization) and FAM (familial relationship)(p<0.05). In both groups, the results between gender were quite different. In female patient group, the total behavior problems were indicated, while in the male patient group, the total behavior problem, internalizing problem as well as somatic complaints were indicated. Especially, indications of ERS and SOM were of statistical significance (p<0.05). CONCLUSION: Children with adenotonsillar hypertrophy have difficulty in adaptation, and lack the ability to respond to situation, and easily get broken down by stress, and experience frequent anxiety.

Change of Voice Quality on Menstrual Cycle / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The change of voice quality on menstrual cycle is regarded as general in professionals. The primary objective of this study is to evaluate the changes of acoustic parameters during menstrual cycle in general population. METHODS: Twenty young adults were asked to produce vowel /a/, /i/ , and /u/ and to read book audibly at the proliferative phase of the menstrual cycle and premenstrual phase. And then, the sound of the voice in each case was recorded and analyzed by the Computerized Speech Lab. (CSL, Kay Elemetrics, Model 4300B, USA). The statistical analyses were performed using paired t-test to compare several variables of data. RESULTS: Compared with the acoustic parameters between two periods, there were no significant differences in all subjects. But the acoustic parameters with book-reading loudly during menstrual cycles revealed slight changes in voice quality. CONCLUSION: The change of voice quality, especially the fatigue of voice may be concerned with menstrual cycle, so more careful voice habituation was required during the menstrual period.

An Acoustic and Radiologic Study on Voice Change after Laser Assisted Uvulopalatoplasty / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Many people have been concerned about voice change after laser assisted uvulopalatoplasty (LAUP). A number of studies reported acoustic changes after uvulopalatopharyngoplasty (UPPP) and LAUP. However, there have not been any reports on the association between anatomic change and acoustic results after LAUP. The purpose of this study is to analyze changes in the voice and changes in the vocal tract after LAUP and to evaluate whether the anatomical changes of vocal tract have an effect on the voice change or not. SUBJECTS AND METHOD: By using CSL, we analyzed fourteen LAUP cases on the formant frequencies of six vowels (/a/, /i/, /u/, /=, /o/, /e/) and four nasal consonants (/hana/, /eomma/, /eoungga/, /chiken/). By using MR image, we analyzed changes in the vocal tract eight weeks after LAUP with preoperative findings in three cases. RESULTS: In acoustic analysis, the second formant frequencies of /u/ and /= phonation were significantly reduced postoperatively compared to those of preoperative status. In imaging study of /u/ and /=, the uvula and soft palate were contracted, so coupling was occurred between nasal cavity and oropharynx in /u/ and /= phonation and the tongue was shifted toward posterior pharyngeal wall to compensate coupling. CONCLUSION: LAUP reduced the second formant of /u/ and /=, which did not result in serious voice changes.