The American journal of otology最新文献

Objective: To determine the outcome of vestibular rehabilitation protocols in subjects with peripheral vestibular disorders compared with normal and abnormal control subjects.

Study design: Prospective study using repeated measure, matched control design. Subjects were solicited consecutively according to these criteria: vestibular disorder subjects who had abnormal results of computerized dynamic posturography (CDP) sensory organization tests (SOTs) 5 and 6 and underwent rehabilitation; vestibular disorder subjects who had abnormal results of SOTs 5 and 6 and did not undergo rehabilitation; and normal subjects (normal SOTs).

Setting: Tertiary neurotology clinic.

Subjects: Men and women over age 18 with chronic vestibular disorders and chief complaints of unsteadiness, imbalance, and/or motion intolerance, and normal subjects.

Interventions: Pre- and post-rehabilitation assessment included CDP, vestibular disability, and activities of daily living questionnaires. Individualized rehabilitation plans were designed and implemented to address the subject's specific complaints and functional deficits. Supervised sessions were held at weekly intervals, and self-administered programs were devised for daily home use.

Main outcome measures: CDP composite and SOT scores, number of falls on CDP, and self-assessment questionnaire results.

Results: Subjects who underwent rehabilitation (Group A) showed statistically significant improvements in SOTs, overall composite score, and reduction in falls compared with abnormal (Group B) control groups. Group A's performances after rehabilitation were not significantly different from those of normal subjects (Group C) in SOTs 3 through 6, and close to normal on SOTs 1 and 2. Subjects in Group A also reported statistically significant symptomatic improvement.

Conclusions: Outcome measures of vestibular protocol physical therapy confirmed objective and subjective improvement in subjects with chronic peripheral vestibular disorders. These findings support results reported by other investigators.

Hypothesis: Blockage of the aeration pathways to the attic may cause circumscribed or widespread alterations that are difficult to diagnose clinically. The narrow route via the posterior pouch to Prussak's space is especially vulnerable to obstruction in recurring otitis media.

Background: Recent studies of the epitympanic diaphragm and compartments have clarified the anatomy of the attic aeration and drainage pathways and emphasized the role of their patency in the healing process of middle ear infections. In neonatal otitis media, the amniotic fluid cellular content (AFCC) has proved to be a good indicator in outlining the areas where inflammation products concentrate, possibly causing early blockage of ventilation.

Methods: Twenty-eight temporal bones from 14 children were studied; 4 of these children had experienced bilateral recurring otitis media. In the latter group, 1 ear was studied by microdissection and the other by serial sectioning.

Results: Prussak's space was involved in all 4 pairs of bones and either contained thick mucus, contained secretion in the process of organization, or was obliterated. The tympanic isthmus was fully obstructed in 1, partially blocked in 2, and open in 5 specimens.

Conclusions: If a thick mature connective tissue mass develops under the epidermal layer of Shrapnell's membrane during an obliteration process of Prussak's space, the condition may stay stable and benign. Severe retraction of Shrapnell's membrane represents a likely forerunner of a retraction pocket cholesteatoma. Systematic otomicroscopy allows early detection, and cure can be achieved by minor surgery. In some children, despite the treatment of recurring otitis media with ventilation tubes, the attic and mastoid can be extensively involved, necessitating atticomastoidectomy and the creation of new pathways for attic aeration.

Purpose: To determine if noise damage in the organ of Corti is different in the low- and high-frequency regions of the cochlea.

Materials and methods: Chinchillas were exposed for 2 to 432 days to a 0.5 (low-frequency) or 4 kHz (high-frequency) octave band of noise at 47 to 95 dB sound pressure level. Auditory thresholds were determined before, during, and after the noise exposure. The cochleas were examined microscopically as plastic-embedded flat preparations. Missing cells were counted, and the sequence of degeneration was determined as a function of recovery time (0-30 days).

Results: With high-frequency noise, primary damage began as small focal losses of outer hair cells in the 4-8 kHz region. With continued exposure, damage progressed to involve loss of an entire segment of the organ of Corti, along with adjacent myelinated nerve fibers. Much of the latter loss is secondary to the intermixing of cochlear fluids through the damaged reticular lamina. With low-frequency noise, primary damage appeared as outer hair cell loss scattered over a broad area in the apex. With continued exposure, additional apical outer hair cells degenerated, while supporting cells, inner hair cells, and nerve fibers remained intact. Continued exposure to low-frequency noise also resulted in focal lesions in the basal cochlea that were indistinguishable from those resulting from exposure to high-frequency noise.

Conclusions: The patterns of cochlear damage and their relation to functional measures of hearing in noise-exposed chinchillas are similar to those seen in noise-exposed humans. Thus, the chinchilla is an excellent model for studying noise effects, with the long-term goal of identifying ways to limit noise-induced hearing loss in humans.

Hypothesis: The purpose of this study was to simulate an isolated directional preponderance (DP) on bithermal caloric testing by constructing a realistic neural network model. The simulation was designed to capture not only the characteristics of the nystagmus response to caloric stimulation but also the response to rotational stimulation in patients with an isolated caloric DP.

Background: The nature of an isolated DP--that is, a DP in the absence of a significant spontaneous nystagmus or canal paresis--is outlined in the preceding article. In this article, the authors investigate the possible neural basis for an isolated caloric DP using the mathematic modeling technique of neural network simulation. Neural network models are typically abstract in nature; however, in this case the network was based on the known structure and function of the central vestibular system.

Methods: The neural network model was based on the known neuroanatomy and neurophysiology of the horizontal vestibuloocular reflex pathway. A leftward-rightward asymmetric modification of the dynamic responses of simulated medial vestibular nucleus type IA neurons on one side, or of type 2 neurons on the other side, to peripheral input would generate an isolated caloric DP.

Results: The values of DP and associated canal paresis produced by the network were within the same range as in the patient group. The network also predicted that the rotational DP would be lower than the caloric DP: between 2.5% and 56.9% of the caloric DP value. The actual rotational DP value was between 3% and 57% (average 41%) of the corresponding caloric DP value.

Conclusions: An isolated caloric DP can be simulated by a neural network model by modifying the activity of model units that represent medial vestibular nucleus neurons. An asymmetric dynamic response by a gain-enhancement function of either type 1A neurons on one side or of type 2 neurons on the other was sufficient to produce an isolated caloric DP. Excitatory gain enhancement of type 2 neurons produced a smaller rotational DP than a similar modification of type 1 neurons. This result indicates a potential neural locus for the generation of an isolated DP in patients with vestibular disorders.

Objective: To test the efficacy and safety of a hyaluronan-based biomembrane in stimulating the healing process in patients undergoing tympanomastoid surgery.

Study design: The trial was an open, two-arm, controlled, randomized, prospective, multicenter study conducted at two different hospitals.

Patients: Sixty subjects (18-65 years of age, both sexes) with chronic cholesteatomatous otitis media were enrolled and treated by the "one-stage open technique." Efficacy and safety parameters were assessed at 3, 5, 7, 9, 11, 13, 17, 21, and 25 weeks after surgery. Three sets of composite criteria were considered: patient's assessment of quality of healing, otomicroscopy, and audiometry.

Results: Of the 60 patients, 50 completed the study. Subjects treated with the biomembrane had statistically significant better scores than controls (no treatment) for all variables considered, excluding audiometry (no significant differences). No adverse events occurred in treated patients.

Conclusion: Data demonstrate that the application of a hyaluronan-based biomembrane improves the healing of the mastoid cavity following "open" tympanoplasty. In particular, re-epithelialization was significantly faster after the application of the biomembrane. Moreover, the device neither caused any adverse events nor showed signs of ototoxicity. Re-epithelialization of open cavities and tympanic grafts still represents for surgeons an unpredictable step in the healing process. Hyaluronian-derivates may effectively contribute to the reduction of such variability.

Objective: The study was conducted to review a staging system proposed by the University of Pittsburgh for temporal bone cancer and to evaluate survival status according to stage, treatment, and certain prognostic factors.

Study design: The study was a retrospective case review.

Setting: The study was conducted at a tertiary care medical center and specialty hospital.

Patients: Thirty-two patients with primary squamous cell carcinoma of the external auditory canal were studied.

Intervention: All patients underwent surgery of the temporal bone. Radiotherapy was given depending on tumor stage and histopathologic findings.

Main outcome measures: The 2-year survival rates of patients undergoing surgical resection with or without adjuvant radiotherapy.

Results: The 2-year survival rates for primary squamous cell carcinoma of the temporal bone were as follows: T1 lesions 100%, T2 80%, T3 50%, and T4 7%. Survival for T3 tumors was 75% with postoperative radiotherapy, compared with 0% with surgery alone.

Conclusions: The 2-year survival data directly correlated with the staging system. The use of adjuvant radiotherapy increased survival rate in patients with a T3 lesion.