A Study for the Acoustic Characteristics of PB Word List according to Frequency / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The Korean phonetically balanced (PB) word list (Ham's Korean PB Word List) is currently the most commonly used word list for speech discrimination test. The aim of this study was to investigate the frequency characteristics of the Ham's Korean PB word list and to compare frequency characteristics of the Ham's Korean PB word list with that of the 21st Century Sejong words, which represent characteristics of the contemporary spoken Korean language. SUBJECTS AND METHOD: The 300 syllables most commonly used were collected from the words in 21st Century Sejong project. The 21st Century Sejong words were weighted according to the frequency of usage. The 21st Century Sejong words and words from the Ham's Korean PB word list were analyzed using an acoustic analysis program that has the MATLAB function. RESULTS: Syllables with frequencies above 2,000 Hz comprise 34% of the 21st Century Sejong words and 16% of the Ham's Korean PB word list. The Ham's Korean PB word list does not represent the high frequency characteristics of the contemporary spoken Korean language. The 21st Century Sejong words have more 'eu', 'i' and open syllables than the Ham's Korean PB word list. CONCLUSION: The Ham's Korean PB word list does not reflect the high frequency characteristics of the contemporary spoken Korean language included in the 21st Century Sejong words. Therefore, a new PB word list that incorporates a greater number of syllables with high frequency characteristics is required.

A Study for the Assessment of Disability and Compensation in Patients with Hearing Impairment / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Disability in hearing impairment represents not only an increase in hearing threshold level, but also unmeasurable subjective discomfort to patients. Until now, several guidelines for quantitative assessment of disability of hearing impairment have been offered. In Korea, laws for industrial accident compensation insurance (IACI) and disabled persons welfare (DPW), and guidelines proposed by American Medical Association (AMA) were frequently used to assess the degree of disability in hearing impaired patients, but there were some discrepancies in the methods and criterions of assessment among the different guidelines and laws. The purposes of this study were to compare these guidelines and look for the problems and to suggest a plan for the improvement in the objective assessment of disability in hearing impaired patients. MATERIALS AND METHOD: The grades of Korean laws for IACI and DPW were converted into the impairment percentage rates used in the AMA guideline. We compared inter-guideline and inter-grade differences in impairment percentage rates. RESULTS: We found several problematic areas in the grades of IACI and there were some differences in the understanding of the degree of disability in hearing impairment between guideline of the Korean laws and foreign guidelines. CONCLUSION: Some changes are needed to be made in the guidelines for disability assessment in the Korean laws for IACI and DPW. Modification of the current grading system into the percentage rating system that is suited to the Korean sociocultural situation would be beneficial in the objective and balanced assessment of the disability of hearing impaired patients.

Dentigerous Cyst Involving the Maxillary Sinus

BACKGROUND AND OBJECTIVES: Dentigerous cysts arise from the reduced enamel epithelium and expand into the surrounding bone. They grow unnoticed to such extensive sizes as to occupy a considerable portion of the maxillary sinus. This study was designed to clarify the clinical, radiological and histopathological features of ten cases of the dentigerous cyst involving the maxillary sinus. MATERIALS AND METHODS: Medical records of ten patients, who were diagnosed with dentigerous cyst, were analyzed from June 1990 to May 2000 retrospectively. RESULTS: The greatest incidence of dentigerous cyst occurred between the ages of 10 and 30 years old (average age 29.6 years). Facial swelling and pain were the most common com-plaints, followed by oro-antral fistula, headache and facial numbness. CT scan of paranasal sinuses showed a slightly nonhomogeneous soft tissue density surrounded by an incomplete bony wall which occupied partially antral space. In the middle of the cyst, the isolated high density of unerupted tooth was seen. In the lining epithelium, the stratified squamous epitheliums were the most frequent. Six patients underwent cyst removal via Caldwell-Luc approach and four patients underwent cyst removal via intraoral approach. The postoperative course has been gone well without recurrence. CONCLUSIONS: The differential diagnosis and early detection of the dentigerous cyst in involving maxillary sinus are important. Rhinologist should be aware of this disease entity when encountered with patients presented with unilateral painful swelling of cheek.

Dentigerous Cyst Involving the Maxillary Sinus

BACKGROUND AND OBJECTIVES: Dentigerous cysts arise from the reduced enamel epithelium and expand into the surrounding bone. They grow unnoticed to such extensive sizes as to occupy a considerable portion of the maxillary sinus. This study was designed to clarify the clinical, radiological and histopathological features of ten cases of the dentigerous cyst involving the maxillary sinus. MATERIALS AND METHODS: Medical records of ten patients, who were diagnosed with dentigerous cyst, were analyzed from June 1990 to May 2000 retrospectively. RESULTS: The greatest incidence of dentigerous cyst occurred between the ages of 10 and 30 years old (average age 29.6 years). Facial swelling and pain were the most common com-plaints, followed by oro-antral fistula, headache and facial numbness. CT scan of paranasal sinuses showed a slightly nonhomogeneous soft tissue density surrounded by an incomplete bony wall which occupied partially antral space. In the middle of the cyst, the isolated high density of unerupted tooth was seen. In the lining epithelium, the stratified squamous epitheliums were the most frequent. Six patients underwent cyst removal via Caldwell-Luc approach and four patients underwent cyst removal via intraoral approach. The postoperative course has been gone well without recurrence. CONCLUSIONS: The differential diagnosis and early detection of the dentigerous cyst in involving maxillary sinus are important. Rhinologist should be aware of this disease entity when encountered with patients presented with unilateral painful swelling of cheek.