Tien-Chen Liu

Deep neck infection: analysis of 185 cases.

This study reviews our experience with deep neck infections and tries to identify the predisposing factors of life‐threatening complications.

Deep neck infection in diabetic patients : Comparison of clinical picture and outcomes with nondiabetic patients

OBJECTIVE: To compare the difference in the clinical picture and outcomes between diabetic and nondiabetic patients with deep neck infections. STUDY DESIGN AND SETTING: We retrospectively reviewed the records of patients who were diagnosed with deep neck infections and who received treatment at the Department of Otolaryngology of National Taiwan University Hospital between 1997 and 2002. One hundred eighty-five patients were included in our study. Fifty-six patients with diabetes mellitus were enrolled for further analysis (diabetic group) and compared with the other 129 patients without diabetes mellitus (nondiabetic group) in demography, etiology, bacteriology, treatment, duration of hospital stay, complications, and outcome. RESULTS: The parapharyngeal space was the space most commonly involved in both the diabetic (33.9%) and nondiabetic groups (40.3%). Odontogenic infections and upper airway infections were the 2 leading causes of deep neck infection in diabetic and nondiabetic groups. Streptococcus viridans is the most commonly isolated organism in the nondiabetic group (43.7%). However, the most common organism in the diabetic group was Klebsiella pneumoniae (56.1%). There were 89.3% of diabetic patients, versus 71.3% of nondiabetic patients, with abscess formation (P = 0.0136). Surgical drainage was performed more frequently in the diabetic group than in the nondiabetic group (86.0% versus 65.2%, P = 0.0142). In comparison with the nondiabetic group, the diabetic group tended to have older mean age (57.2 y versus 46.2 y, P = 0.0007), longer duration of hospital stay (19.7 days versus 10.2 days, P >0.0001), more frequent complications (33.9% versus 8.5%, P >0.0001), and more frequent tracheostomy or intubation (19.6% versus 6.2%, P = 0.0123). CONCLUSIONS: Patients with diabetes mellitus are susceptible to deep neck infection. We should pay more attention when dealing with deep neck infections in patients with diabetes mellitus because those patients tend to have complications more frequently and a longer duration of hospital stay. Empirical antibiotics should cover K. pneumoniae in patients with deep neck infection who have diabetes mellitus.

Association of central obesity with the severity and audiometric configurations of age-related hearing impairment.

To investigate the effect of central obesity on the severity and characteristics of age‐related hearing impairment (ARHI), we recruited 690 adult subjects with normal or symmetrical sensorineural hearing loss (SNHL). The effects of age, gender, morphometry, habits, systemic diseases, and environmental noise exposure on average pure tone hearing level at low frequencies (pure tone audiometry (PTA)‐low) and high frequencies (PTA‐high) were analyzed. After adjusting for age, gender, systemic disease, and other variables, waist circumference (WC) showed a significant positive association with PTA‐low and PTA‐high. In females, PTA‐low and PTA‐high only showed significant positive association with age, but not with WC or other variables. However, PTA‐high showed a positive association with borderline significance with WC in female subjects older than 55. In males, WC as well as age and noise exposure showed significant positive associations with both PTA‐low and PTA‐high, primarily in subjects younger than 55. When both WC and BMI were taken into account in a backward stepwise multivariate linear regression analysis, WC, but not BMI, showed a significant positive association with PTA‐low and PTA‐high in males younger than 55, and with PTA‐high with borderline significance in females older than 55. However, the audiogram patterns were not significantly affected by central obesity in either age or gender. Our results suggest that WC was, even after adjustment for BMI, an independent risk factor of ARHI, particularly for low and high frequencies in males younger than 55 and for high frequencies in female subjects older than 55.

Three‐Dimensional Reconstruction and Modeling of Middle Ear Biomechanics by High‐Resolution Computed Tomography and Finite Element Analysis

Objective: To present a systematic and practical approach that uses high‐resolution computed tomography to derive models of the middle ear for finite element analysis.

Aging Effects on the Activation of the Auditory Cortex during Binaural Speech Listening in White Noise: An fMRI Study

The functional significance of age-related pathology of the auditory cortex is not well established. The purpose of this study was to elucidate the activation pattern of the auditory cortex in aged subjects in response to speech signals. Functional magnetic resonance imaging was performed on 12 elderly subjects with normal hearing acuity during selective listening with both ears to speech sounds in quiet and in white noise. Twelve young, normal-hearing subjects served as controls. Our results showed that activation of the auditory cortex during selective listening to speech decreased in elderly subjects compared to young subjects, especially in noise. Reduced activation occurred in the anterior and posterior regions of the bilateral superior temporal gyrus (STG), but mainly in the posterior part of the left STG. In addition, background noise had a greater masking effect on speech perception in the elderly subjects than in the young ones. These findings suggest that early functional changes associated with central presbycusis occur mainly in the posterior part of the left STG.

Optimal Graft Thickness for Different Sizes of Tympanic Membrane Perforation in Cartilage Myringoplasty: A Finite Element Analysis†

Objective: The purpose of this study was to determine, using finite element analysis, the optimal graft thickness for cartilage myringoplasty in patients with different sizes of tympanic membrane (TM) perforations.

Community-acquired methicillin-resistant Staphylococcus aureus infections in discharging ears.

Objectives --Although community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections have recently become an increasing problem in various fields of medicine, they have rarely been studied in the ear. The purpose of this study was to determine the prevalence of community-acquired MRSA infections in discharging ears and to compare the epidemiology of MRSA with that of other pathogens. Material and methods --Between August 2000 and February 2002, 248 isolates recovered from 221 discharging ears of patients with 3 disease entities (chronic otitis media, acute otitis externa and granular myringitis) were prospectively analyzed using bacteriology. The isolates analyzed using bacteriology were divided into three groups: MRSA, methicillin-susceptible S. aureus (MSSA) and non-SA. Results --S. aureus was found in 108 (43.5%) isolates and MRSA in 27. Therefore, the percentage of MRSA among the S. aureus isolates was 25.0% (27/108). The prevalence of community-acquired MRSA infections in discharging ears was 12.2% (27/221) and the MRSA strains were highly susceptible to vancomycin, teicoplanin, fusidic acid and minocycline. The MRSA-infected patients were older than those infected with other groups of pathogens. Also, MRSA infections appeared to be more common in chronic otitis media than in acute otitis externa or granular myringitis. Conclusions --Community-acquired MRSA represents an increasing problem. In this study, MRSA strains were highly susceptible to vancomycin, teicoplanin, fusidic acid and minocycline.

Association of plasma adiponectin levels with hearing thresholds in adults

Objective  Obesity is an independent risk factor for age‐related hearing impairment. Adiponectin is one of the major adipocytokines secreted by adipose tissue. The aim of our study was to examine whether there is an association between plasma adiponectin concentrations and hearing sensitivity in adults.

A novel opto-electromagnetic actuator coupled to the tympanic membrane

A new type of electromagnetic vibration transducer designed to be placed onto the tympanic membrane was developed. The actuator consisted of two photodiodes, two permanent magnets, an aluminum ring, two opposing wound coils, a latex membrane and a Provil Novo membrane. An optic probe was designed to allow sound and light signals to enter the ear canal, thereby preventing the acoustic occlusion effect of traditional ear molds. Two light-emitting diodes were used for carrying the input signals. The corresponding photodiodes were used for receiving the light signals and generating currents in the actuator. The opto-electromagnetic vibration actuator was fabricated and tested using a Laser Doppler vibrometer. The actuator showed displacements of vibration between 30 and 1 nm from 300 to 6500Hz and reduced in amplitude at higher frequencies. The average gain of the actuator with 140microA on the umbo displacement was about 20 dB relative to 87 dBA at the distance of 6cm from the tympanic membrane and 0microA in actuator.

Diffusion Tensor Imaging of the Subcortical Auditory Tract in Subjects with Congenital Cochlear Nerve Deficiency

BACKGROUND AND PURPOSE: Cochlear nerve deficiency (CND), including aplasia and hypoplasia, is a rare cause of congenital hearing loss. The purpose of this study was to evaluate the neuronal integrity of the subcortical auditory pathway in subjects with CND by diffusion tensor MR imaging (DTI). MATERIALS AND METHODS: Twelve subjects with unilateral congenital CND were included in this prospective study. Twelve normal-hearing subjects served as controls. DTIs were acquired from these subjects on a 3T MR imaging scanner. Several indices including axial diffusivity (λ‖), radial diffusivity (λ⊥), mean diffusivity (MD), and fractional anisotropy (FA) along the auditory pathway were extracted. Two regions of interest were selected bilaterally for evaluation: the lateral lemniscus (LL) and inferior colliculus (IC). The mean values of λ‖, λ⊥, MD, and FA at both regions of interest were compared between the ipsilateral and contralateral sides of subjects with CND with those in the control group. RESULTS: Significant decrease of FA and increase of MD on both the ipsilateral and contralateral sides of patients with CND as compared with normal subjects in both LL and IC were found. The decrease of FA was due to the increase of λ⊥, whereas λ‖ remained unchanged. CONCLUSIONS: The maintained axial diffusion implied that the orientation of neural fibers along the subcortical auditory pathway in subjects with unilateral CND is intact. However, the reduction in FA and increase in λ⊥ on both the ipsilateral and contralateral sides might be attributed to axonal loss and/or demyelination of the subcortical auditory tract in these subjects.