Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bone Conduction”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,783 records · Page 99Linked to original sources
PubMed1992

Long-term results of surgery for childhood cholesteatoma.

The study includes 54 cholesteatomatous ears in 50 children aged 16 years or less. The mean follow-up period after surgery was 7.1 years. In 26% of the ears the cholesteatoma was 'huge' involving the middle ear and the attic and filling the entire mastoid air cell system. A patient had lateral sinus thrombophlebitis. Patients with large cholesteatomas underwent canal wall down mastoidectomy with simultaneous tympanoplasty and, in most cases, cavity obliteration. Limited cholesteatomas were removed using either intact canal wall mastoidectomy or tympanotomy approach. Recurrence rate (including both residual and recurrent cholesteatomas) for the total series was 15% and 12% for the 50 cases undergoing one-stage surgery. Serviceable hearing (< or = 30 dB) was achieved in 57% of the ears. A reoperation was necessary in 26% and a third operation in 2%. At last follow-up examination, 94% of the ears had intact tympanic membranes but 4 patients (8%) suffered from cavity-related problems. Possible reasons for the disappointing results of surgical treatment for childhood cholesteatoma are discussed.

Adolescent↗
PubMed1992

Results of surgical treatment for chronic noncholesteatomatous otitis media in the pediatric population.

The long-term results of surgery for chronic otitis media without cholesteatoma were analyzed in 76 ears of children aged 16 years or less. The mean follow-up period was 6.0 years. Thirty-four ears were subjected to mastoid surgery for chronic otorrhea; at final follow-up examination the disease was found to be cured in all but one patient. Forty-two patients with sequelae to chronic otitis media underwent tympanoplasty without mastoidectomy which was successful in 38 (91%) of these. At follow-up, 84% of the patients had hearing levels of 20 dB or better. Outcome of surgery and hearing results in children were as good as or even better than those obtained in adult patients. Complications of surgery were rare.

Adolescent↗
PubMed1996

Camurati-Engelmann disease presenting as 'juvenile otosclerosis'.

Camurati-Engelmann disease (CED, MIM # 131300) was diagnosed in a 27-year-old woman, who had pain in her lower legs. There was no history of hearing loss (or CED) in her family. She had been suffering from progressive hearing impairment since childhood. Serial audiograms demonstrated progressive mixed hearing loss from the age of 11 years onwards, for which she underwent successful stapes surgery bilaterally at the age of 13-18 years. Clinical ('juvenile') otosclerosis was found with stapes footplate fixation. Unfortunately, the sensorineural hearing loss component proved to be progressive bilaterally after surgery. At the age of 30 years, she experienced more rapid deterioration of her hearing loss in the right ear and episodes of vertigo. Vestibular examinations demonstrated progressive vestibular impairment 'otospongiotic' lesions with encroachment on the cochlear and vestibular labyrinth were found on high resolution CT scans at the age of 40 years; the internal auditory canal was normal bilaterally. CED may have formed a chance combination with juvenile otosclerosis in our patient, or otosclerosis may be part of the CED phenotype.

Adult↗
PubMed1991

Proton pathways in lysozyme.

Protonic conduction studies are reported for lysozyme as a function of the number of bound water molecules. Lysozyme samples employing proton-injecting palladium black electrodes exhibited conductivities up to eight orders of magnitude greater than those retained between control (copper) electrodes. The results indicate that water involved in multiple hydrogen bond contact with the enzyme together with hydrogen bonded segments of the enzyme structure provide a hydrogen bond network which is capable of supporting considerable protonic conduction.

Copper↗
PubMed1984

Notes on the comparative mechanics of hearing. I.A shock-proof ear.

In woodpeckers, the cochlear windows show functional specialization. The small membrane of the round window is attached to a special bony plate of the columella. This arrangement of coupled windows probably increases power dissipation at the fenestral boundaries and so dampens impulsive mechanical disturbances.

Animals↗
PubMed1995

Auditory pathway plasticity in adult humans after unilateral idiopathic sudden sensorineural hearing loss.

We recorded auditory evoked magnetic fields from 8 patients with unilateral, idiopathic, sudden, sensorineural hearing loss and from 8 healthy controls, using a 122-channel whole-scalp neuromagnetometer. The stimuli were 50-ms l-kHz tone bursts, delivered to the healthy ear at interstimulus intervals (ISIs) of 1, 2, 4, 8, and 16 s. On average, as in normal-hearing controls, the dipole moments and the latencies of N100m, the 100-ms response, increased as a function of ISI over both hemispheres to left- and right-ear stimulation. Four patients had shorter response latencies and 4 had stronger dipole moments over the hemisphere ipsilateral to the stimulation. In 3 patients, one additional source was observed over the anterolateral right hemisphere and another near head midline. These findings suggest that unilateral sensorineural hearing loss may modify information processing in the central auditory pathways.

Acoustic Stimulation↗
PubMed2005

Susceptibility of aging human bone to mixed-mode fracture increases bone fragility.

Since bone-mass-based measurements have demonstrated limited success in predicting age-related increase in fracture incidence, recent emphasis has been placed on quantification of bone quality. Specifically, material parameters such as strength, stiffness, and toughness have been quantified to characterize bone quality through mechanical testing. This study is the first one to report multiaxial failure characteristics of bone (quality) by conducting fatigue tests on human cortical bone specimens under physiologically relevant loading involving simultaneous application of axial and torsional loading to produce previously reported in vivo shear/normal stress ratios. Our results show that, compared to uniaxial tests, multiaxial fatigue tests show up to a 20-fold reduction in the fatigue life of human cortical bone. More significantly, the susceptibility of mixed-mode failure increases bone fragility in aging human bone. Furthermore, since the magnitude of mixed-mode loading varies with physiological activities, results of this study also suggest that a reduction in the activities involving significant mixed-mode loading may lower the overall fracture incidence among older individuals.

Adult↗
PubMed2006

Lateral graft type 1 tympanoplasty using AlloDerm for tympanic membrane reconstruction in children.

OBJECTIVES: To describe the lateral graft type 1 tympanoplasty technique using AlloDerm for tympanic membrane reconstruction in children and to compare its surgical and audiometric outcomes with the traditional underlay type 1 tympanoplasty. METHODS: The records of 34 consecutive children undergoing type 1 tympanoplasty between 2004 and 2005 were reviewed; 18 received lateral graft tympanoplasty with AlloDerm and 16 received underlay tympanoplasty (8 AlloDerm and 8 temporalis fascia). Pre- and post-surgical audiograms, speech reception threshold, closure rate and complication rate were evaluated using one-way and repeated measures ANOVAs. RESULTS: Children who underwent lateral graft type 1 tympanoplasty pre-operatively had larger tympanic membrane perforations, worse pure tone averages, air bone gaps and speech reception thresholds as compared with children undergoing underlay type 1 tympanoplasty (P<0.001). Pure tone averages and air bone gaps improved significantly with surgery in both lateral and underlay type 1 tympanoplasty groups (P<0.05), with both groups achieving comparable postoperative audiometric outcomes (P>0.01). The lateral graft group demonstrated a higher perforation closure rate (94%) as compared with both underlay groups (88%). Complication rates were virtually non-existent. CONCLUSIONS: Despite larger perforations and worse pre-operative audiometric scores, children who underwent lateral graft type 1 tympanoplasty achieved comparable postoperative audiometric results and perforation closure rates as compared with children who underwent underlay type 1 tympanoplasty. Results suggest that lateral graft type 1 tympanoplasty using AlloDerm is effective for tympanic membrane reconstruction in children and should be used when temporalis fascia is not available or the extent of the perforation limits its use.

Adolescent↗
PubMed2005

Acoustic-structural coupled finite element analysis for sound transmission in human ear--pressure distributions.

A three-dimensional (3D) finite element (FE) model of human ear with accurate structural geometry of the external ear canal, tympanic membrane (TM), ossicles, middle ear suspensory ligaments, and middle ear cavity has been recently reported by our group. In present study, this 3D FE model was modified to include acoustic-structural interfaces for coupled analysis from the ear canal through the TM to middle ear cavity. Pressure distributions in the canal and middle ear cavity at different frequencies were computed under input sound pressure applied at different locations in the canal. The spectral distributions of middle ear pressure at the oval window, round window, and medial site of the umbo were calculated and the results demonstrated that there was no significant difference of pressures between those locations at frequency below 3.5 kHz. Finally, the influence of TM perforation on pressure distributions in the canal and middle ear cavity was investigated for perforations in the inferior-posterior and inferior sites of the TM in the FE model and human temporal bones. The results show that variation of middle ear pressure is related to the perforation type and location, and is sensitive to frequency.

Acoustic Stimulation↗
PubMed2006

Reversible peripheral vestibulopathy: the treatment of superior canal dehiscence.

OBJECTIVE: Superior canal dehiscence (SCD) is a recently described disorder that results from absence of bone over the superior semicircular canal. We have reviewed 30 cases of SCD found at our institution and report their presentation, workup, and response to therapy. STUDY DESIGN: Retrospective chart review of all patients diagnosed with SCD from 1999 to 2004 at the University of Utah. RESULTS: Thirty patients were identified with SCD. Patients presented with chronic disequilibrium (63%), Tullio's phenomenon (41%), pressure evoked vertigo (44%), hearing loss (30%), and pulsatile tinnitus (7%). ENG performed early in our series revealed abnormal nystagmus with sound presentation, Valsalva, or tympanogram; however, history and CT examination alone was used to identify this condition in most of our patients. Twenty-seven of the 30 patients had some symptoms related to SCD; the other 3 were found to have incidental SCD on CT examination. Of these patients, 14 had severe enough symptoms to warrant operative intervention. All, but one had resolution of their symptoms after completion of intervention. CONCLUSIONS: Superior canal dehiscence is a highly treatable form of vestibulopathy once recognized. When patients present with typical symptoms, workup with CT is reliable and accurate. Surgical intervention results in reversal of symptoms in most cases with low morbidity. EBM RATING: C-4.

Acoustic Impedance Tests↗
PubMed2006

Computed tomography in the diagnosis of otosclerosis.

OBJECTIVES: To identify the main tomographic findings of otosclerosis and to evaluate the usefulness of high-resolution computed tomography as a diagnostic method for this osteodystrophy. STUDY DESIGN AND SETTING: A prospective and multicenter study consisting of computed tomography (CT) of the temporal bone was conducted on 54 patients with a clinical and surgical diagnosis of otosclerosis. Twenty-two patients were included in the control group. RESULTS: The CT scan was positive in 87% of the patients. The tomographic findings were mainly bilateral and fenestral foci were more prevalent. CONCLUSIONS: CT showed a high rate of positivity, mainly for fenestral lesions. Foci anterior to the oval window were the most prevalent in this population. SIGNIFICANCE: CT is useful as a diagnostic method and therapeutic indicator of otosclerosis. EBM RATING: B-3b.

Adolescent↗
PubMed2001

Biomechanical evaluation of two halo pin designs, with, and without, intact periosteum.

The presence of periosteum has been hypothesized to adversely affect halo pin penetration and performance (Voor, 1992. Ph.D. Dissertation, Tulane University, New Orleans, LA). However, biomechanical testing of halo pins has historically been conducted on bone specimens with periosteum removed. This may have lead to an unrealistic measure of biomechanical pin performance. Our study compares the biomechanical performance of two halo pin designs on bovine bone specimens with, and without, intact periosteum. The two pin designs included in this study were the conventional pin (Bremer Medical) with conical tip, and a newly released trochar-style pin (DePuy AcroMed). Results showed the mean peak load before failure of the trochar-style pin (mean +/- 95% confidence interval: 656+/-29 N) to be significantly higher than the conventional pin (517+/-53 N) on bone with intact periosteum (p = 0.001). With the periosteum removed, the mean peak load of the trochar-style pin (655+/-99 N) remained statistically the same (p = 0.987), while the mean peak load of the conventional pin (634+/-65 N) increased significantly (p = 0.026). Variation of the data of the conventional pin significantly decreased from 32 to 19% on removal of periosteum (sigma = 165-103 N, respectively, p = 0.0967), while variation of the trochar-style remained statistically the same at 30-29% (sigma = 193-188 N, respectively, p = 0.954). These results show that the trochar-style pin may be biomechanically superior to the conventional pin for vertical forces experienced during immobilization. The performance of this new pin style may also not be significantly affected by overlying soft tissue. Use of this new pin style may, therefore, improve overall stability and fixation of the halo apparatus.

Animals↗
PubMed2002

Audiologic assessment of children with suspected hearing loss.

In assessing children with suspected hearing loss, audiologists are faced with the challenge of attempting to describe auditory function in a population that presents with a wide range developmental levels and abilities. Fortunately, there are a number of behavioral and physiologic tools available for the evaluation of auditory sensitivity and system integrity in children of all ages and developmental abilities. As powerful as many of these tools may be, however, it is important that the diagnosis of hearing loss be based on the outcome of independent measures of auditory function, which serve to cross-check and complement one another. Failure to do so is likely to result in inaccurate or incomplete delineation of auditory function.

Acoustic Impedance Tests↗