Comparisons in Outcome and Subject Comfort between Rotation Chair Systems

BACKGROUND AND OBJECTIVES: A rotation chair test has been used to evaluate the function of the horizontal semicircular canals. Currently, two chair systems according to the presence of cylindrical darkroom are used in a clinic setting. However, it has not been thoroughly investigated whether one system is superior to the other system or not. In this study, we aimed to compare test outcomes and subject convenience between two systems. SUBJECTS AND METHODS: Twenty subjects with no history of otologic disease were enrolled. Subjects were tested with two systems: system [A] with a cylindrical chamber and system [B] with no chamber. The results of sinusoidal harmonic acceleration (SHA), step velocity (SV), and visual fixation (VFX) tests were compared between the systems. Subject convenience was assessed with a questionnaire survey and results were compared between the systems. RESULTS: There were no significant differences in gain or asymmetry in SHA test between the systems. However, the phase of system [A] was significantly lower than that of system [B] at 0.16 Hz. There was no significant difference between the systems in directional preponderance (DP) gain or DP time constant. Regarding the VFX test, gain was higher in system [A] than system [B]. Subjects reported less stuffiness and less anxiety with system [B] than system [A], while preferring the system [A] goggles. CONCLUSIONS: A rotation chair system without a darkroom can provide a more comfortable experience for subjects in terms of stuffiness and anxiety, while showing comparable results in SHA and SV tests with a darkroom system.

Cryopreservation of Cartilage for Transplantation in Rhinoplasty: A Literature Review / 대한이비인후과학회지

Although many rhinosurgeons still use cryopreserved septal or rib cartilage for grafts in rhinoplasty, there is no consensus whether it is an effective method preserving the chondrocyte viability. To propose a best option in the ex-vivo preservation of cartilage by literature review. A critical review of the published literature using PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) with particular emphasis on studies which include cartilage cryopreservation was performed. Using databases, articles published from 1956 through 2011 for all available studies reporting cryopreservation of cartilage were investigated. Keywords used in this search were "cryopreservation", "nasal cartilage", "articular cartilage", "chondrocytes", and "rhinoplasty". We could confirm that isolated chondrocytes can be effectively cryopreserved, yet the survival of chondrocytes in cryopreserved intact cartilage tissue is inadequate and extremely variable. Hypothermic preservation of intact cartilage in culture media showed good cell viability and function up to 2 weeks only. Though it is possible to cryopreserve one cell-layer tissue with the preservation of a high percentage of the initial cells, successful methods for cryopreservation of whole cartilage have not been achieved despite numerous efforts world-wide. Preserving the whole cartilage tissue at 4℃ in culture media proved that the tissue showed good viability with metabolic activity for 2 weeks.

Conditions of Cervical Vestibular Evoked Myogenic Potentials Test to Minimize Interaural Variation / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Cervical vestibular evoked myogenic potentials (cVEMP) test has been widely used to assess the function of the saccule and inferior vestibular nerve. Electrode location and stimulating sound are important factors which might affect the test results. Today those parameters are usually selected to maximize the waveform response. In this study, we tried to find the optimal condition to minimize the range of normal value of cVEMP. SUBJECTS AND METHOD: Thirteen normal subjects (26 ears) were included. We placed electrodes at five different locations over the sternocleidomastoid muscle (SCM) and used four different stimulation sounds. Variances of parameters, including interpeak amplitude, interaural difference (IAD) and normal value were analyzed and compared. RESULTS: When using the classical condition (mid point of SCM and 500 Hz) without rectification, IAD ratio was 20.8+/-14.2% and the range of normal value was 39%. When we used 2000 Hz tone burst sound at the classical electrodes site, IAD ratio and normal value were minimized, resulting in 18.7+/-14.3% and 31% respectively. After the rectification, when using the classical condition, IAD ratio was 26.4+/-22.3% and the range of normal value was 49%. The minimum IAD ratio was measured as 17.4+/-13.7% when we used click sound at SCM at the level of mandibular angle. And the minimum normal value of 32% was measured when we used 1000 Hz tone burst sound at SCM at the level of mandibular angle. CONCLUSION: Although the condition was not optimal for maximizing the interpeak amplitude, we could alternatively use the condition to minimize the normal value.

Cochleovestibular Otosclerosis Without Conductive Hearing Loss / 대한평형의학회지

Otosclerosis typically starts around stapes footplate presenting conductive hearing loss initially. However, otosclerosis may involve cochlea and vestibule causing sensorineural hearing loss and dizziness. We report a case of cochleovestibular otosclerosis without conductive hearing loss featuring Meniere's disease.

Effect of Active Noise Cancelling Earphones on Preferred Listening Level When Listening to Portable Music Players in Noisy Environments / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Active noise cancelling (ANC) is a technology that can reduce external noise by producing a signal that is similar to noise but different in that it has an opposite phase to noise. Nowadays ANC has become an important technology in the field of hearing aids, but many studies have not focused on the effect of ANC of earphones when listening to portable music players. In this study, we aimed to evaluate whether ANC earphones can effectively reduce external noise and lower the preferred listening level. SUBJECTS AND METHOD: Three different earphones (Ear-canal, On-the-ear, Covering-the-ear) were tested in three different noise environments. Nine participants were tested in 10 experiments. First, through the real ear measurement (REM) system, we evaluated the differences in sound pressure level when the ANC was either turned on or off. Second, we evaluated the effects of ANC on Preferred Listening Level (PLL) for participants listening to the same song with different earphones. Through the REM system, we evaluate the level of sound pressure level when participants controlled the volume and felt most comfortable with the volume level. RESULTS: All three types of earphones showed statistically significant effects on noise reduction when ANC was turned on. The noise reduction effect was most prominent with the Ear-canal earphone. All three types of earphones also showed statistically significant effect on PLL reduction. CONCLUSION: ANC earphones may be helpful in noise reduction and preventing noise induced hearing loss when listening to music in noisy environments. Among the three types of earphones, Ear-canal earphone seems to be the most effective in noise reduction.