Biomedical subjects

Ted A Meyer

Publications and source records attributed to Ted A Meyer.

4 recordsLinked to original sources

PubMed2006

Small acoustic neuromas: surgical outcomes versus observation or radiation.

OBJECTIVE: Evaluate factors affecting outcomes of small acoustic neuroma (AN) removal via a middle cranial fossa (MCF) approach, and compare results to published data on observation and radiation therapy. STUDY DESIGN: Retrospective chart review. SETTING: Academic tertiary referral center. METHODS: 162 consecutive patients (ages 19-70) with unilateral AN (0.2-2.5 cm in largest dimension) removed through a MCF approach were reviewed focusing on preservation of hearing, facial nerve function and complications. One hundred thirteen patients had pre-operative word recognition scores (WRS)>70%. RESULTS: Both tumor size and pre-operative WRS were related to post-operative WRS (p<0.01). Overall, at least some hearing was preserved in 94 (60%) of the 156 patients who had hearing before surgery. If the WRS was also >70% (N=113), 56 (50%) maintained WRS>70%. Importantly, WRS for 12 others improved to >70% after surgery. When the patients were stratified by tumor size, the patients with small tumors (2-10 mm) faired better than the overall group. At least some hearing was preserved in 65 (72%) of the 90 patients. If the WRS was also >70% (N=66), 39 (59%) maintained WRS>70%. WRS for eight others improved to >70% after surgery. When the tumor was 1.1-1.4 cm (N=34), the chance of preserving some hearing decreased to 42% (14/33). If the WRS was also >70% (N=23), 9 (39%) maintained WRS>70%. WRS for three others improved to >70% after surgery. When the tumor reached 1.5-2.5 cm (N=35), the hearing preservation rate was 43%. If the WRS was also >70% (N=24), only eight (33%) maintained WRS of 70%, and one other improved to >70%. The addition of intra-operative whole eighth nerve near field monitoring improved results during small tumor ( 70% WRS in 76% (22/29) of those with >70% pre-operative WRS. Good facial nerve function (HB I-II) was achieved in 97% (86% HB I). When tumor size was <or=1.0 cm (N=93), however, good facial nerve function was obtained in 100% (94% HB I). Complications included CSF leak: 9 (5.5%); seizure: 2 (1.2%); and recurrence: 1 (0.6%). CONCLUSION: Our results suggest that removal of unilateral AN through an MCF approach when the tumor is small and hearing is good provides the best opportunity for hearing preservation and normal facial nerve function. Observation historically results in tumor growth in young and middle-age patients with subsequent hearing loss. Radiation may prevent most tumors from growing, and more data are needed to determine long-term tumor control and hearing preservation rates.

Action Potentials↗

PubMed2004

Case report: Cochlear implant magnet migration.

A 13-month-old cochlear implant recipient underwent routine device activation. Three months postoperatively, the patient sustained a fall with contact to the area of the implant without immediate complication. Ten months postoperatively, the position of the external coil appeared to have moved and the patient did not seem to be responding as well to sound. Audiological testing could not elicit normal device impedances. AP and lateral plain radiographs of the skull revealed migration of the internal magnet from its position within the internal coil to a position over the receiver/stimulator. This is the first known published case of cochlear implant magnet migration.

Cochlear Implants↗

PubMed2004

Primary and revision stapedectomy in elderly patients.

PURPOSE OF REVIEW: This review discusses the recent literature on short- and long-term hearing results for primary and revision stapes surgery on young and elderly patients. RECENT FINDINGS: The epidemiology of clinical otosclerosis appears be changing. The average age for patients undergoing primary stapes surgery is increasing, and the percentage of revision stapedectomies is increasing. As the population ages, the otologist should expect to perform more surgeries on elderly patients. Short- and long-term hearing results after primary stapes surgery are good, regardless of age. Approximately 90% of patients obtain closure of their ABG to within 10 dB. Long-term results demonstrate that hearing decreases over time after stapedectomy at a rate of approximately 1 dB/y for both young and elderly populations. Sensorineural hearing loss accounts for most of this decrease and a relatively small ABG is maintained in many patients. However, at least 10 to 20% of patients will redevelop conductive hearing loss after undergoing stapes surgery and will desire revision surgery to correct this hearing loss. With modern otologic equipment, including the laser, most patients undergoing revision stapedectomy should obtain significant improvement in hearing, regardless of age. SUMMARY: Primary and revision stapedectomy are beneficial procedures in the elderly population. The success rate is similar to that in the younger population with otosclerosis.

Aged↗

PubMed2003

Modeling open-set spoken word recognition in postlingually deafened adults after cochlear implantation: some preliminary results with the neighborhood activation model.

HYPOTHESES: Do cochlear implants provide enough information to allow adult cochlear implant users to understand words in ways that are similar to listeners with acoustic hearing? Can we use a computational model to gain insight into the underlying mechanisms used by cochlear implant users to recognize spoken words? BACKGROUND: The Neighborhood Activation Model has been shown to be a reasonable model of word recognition for listeners with normal hearing. The Neighborhood Activation Model assumes that words are recognized in relation to other similar-sounding words in a listener's lexicon. The probability of correctly identifying a word is based on the phoneme perception probabilities from a listener's closed-set consonant and vowel confusion matrices modified by the relative frequency of occurrence of the target word compared with similar-sounding words (neighbors). Common words with few similar-sounding neighbors are more likely to be selected as responses than less common words with many similar-sounding neighbors. Recent studies have shown that several of the assumptions of the Neighborhood Activation Model also hold true for cochlear implant users. METHODS: Closed-set consonant and vowel confusion matrices were obtained from 26 postlingually deafened adults who use cochlear implants. Confusion matrices were used to represent input errors to the Neighborhood Activation Model. Responses to the different stimuli were then generated by the Neighborhood Activation Model after incorporating the frequency of occurrence counts of the stimuli and their neighbors. Model outputs were compared with obtained performance measures on the Consonant-Vowel Nucleus-Consonant word test. Information transmission analysis was used to assess whether the Neighborhood Activation Model was able to successfully generate and predict word and individual phoneme recognition by cochlear implant users. RESULTS: The Neighborhood Activation Model predicted Consonant-Vowel Nucleus-Consonant test words at levels similar to those correctly identified by the cochlear implant users. The Neighborhood Activation Model also predicted phoneme feature information well. CONCLUSION: The results obtained suggest that the Neighborhood Activation Model provides a reasonable explanation of word recognition by postlingually deafened adults after cochlear implantation. It appears that multichannel cochlear implants give cochlear implant users access to their mental lexicons in a manner that is similar to listeners with acoustic hearing. The lexical properties of the test stimuli used to assess performance are important to spoken-word recognition and should be included in further models of the word recognition process.

Adult↗