-
[show abstract]
[hide abstract]
ABSTRACT: Unilateral hearing in childhood restricts input along the bilateral auditory pathways, possibly causing permanent reorganization. In this study we asked: (i) do the auditory pathways develop abnormally in children who are bilaterally deaf and hear with a unilateral cochlear implant? and (ii) can such differences be reversed by restoring input to the deprived ear? We measured multichannel electroencephalography in 34 children using cochlear implants and seven normal hearing peers. Dipole moments of activity became abnormally high in the auditory cortex contralateral to the first implant as unilateral cochlear implant use exceeded 1.5 years. This resulted in increased lateralization of activity to the auditory cortex contralateral to the stimulated ear and a decline in normal contralateral activity in response to stimulation from the newly implanted ear, corresponding to poorer speech perception. These results reflect an abnormal strengthening of pathways from the stimulated ear in consequence to the loss of contralateral activity including inhibitory processes normally involved in bilateral hearing. Although this reorganization occurred within a fairly short period (∼1.5 years of unilateral hearing), it was not reversed by long-term (3-4 years) bilateral cochlear implant stimulation. In bilateral listeners, effects of side of stimulation were assessed; children with long periods of unilateral cochlear implant use prior to bilateral implantation showed a reduction in normal dominance of contralateral input in the auditory cortex ipsilateral to the stimulated ear, further confirming an abnormal strengthening of pathways from the stimulated ear. By contrast, cortical activity in children using bilateral cochlear implants after limited or no unilateral cochlear implant exposure normally lateralized to the hemisphere contralateral to side of stimulation and retained normal contralateral dominance of auditory input in both hemispheres. Results demonstrate that the immature human auditory cortex reorganizes, potentially permanently, with unilateral stimulation and that bilateral auditory input provided with limited delay can protect the brain from such changes. These results indicate for the first time that there is a sensitive period for bilateral auditory input in human development with implications for functional hearing.
Brain 04/2013; · 9.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study examined the ability of prelingually deaf children with bilateral implants to identify emotion (i.e. happiness or sadness) in speech and music.
Participants in Experiment 1 were 14 prelingually deaf children from 5-7 years of age who had bilateral implants and 18 normally hearing children from 4-6 years of age. They judged whether linguistically neutral utterances produced by a man and woman sounded happy or sad. Participants in Experiment 2 were 14 bilateral implant users from 4-6 years of age and the same normally hearing children as in Experiment 1. They judged whether synthesized piano excerpts sounded happy or sad.
Child implant users' accuracy of identifying happiness and sadness in speech was well above chance levels but significantly below the accuracy achieved by children with normal hearing. Similarly, their accuracy of identifying happiness and sadness in music was well above chance levels but significantly below that of children with normal hearing, who performed at ceiling. For the 12 implant users who participated in both experiments, performance on the speech task correlated significantly with performance on the music task and implant experience was correlated with performance on both tasks.
Child implant users' accurate identification of emotion in speech exceeded performance in previous studies, which may be attributable to fewer response alternatives and the use of child-directed speech. Moreover, child implant users' successful identification of emotion in music indicates that the relevant cues are accessible at a relatively young age.
Cochlear implants international 03/2013; 14(2):80-91.
-
[show abstract]
[hide abstract]
ABSTRACT: Objectives The objectives of this study were to determine the incidence of acquired cholesteatoma in children with congenital cleft palate, and to determine the impact of various cleft palate types (cleft lip and palate, cleft palate alone, submucous cleft palate) on the development of acquired cholesteatoma. Materials and methods This is a retrospective cohort study spanning a 25-year period from 1981 to 2005. The Cleft Palate Registry at the Hospital for Sick Children in Toronto, Canada was cross-referenced with the hospital's surgical pathology database to identify all children with cleft palate and acquired cholesteatoma. Accuracy and completeness of the datasets were confirmed by comparison with hospital records and other databases. Results There were 2737 children who underwent palatoplasty over the study period, and 44 of these children developed an acquired cholesteatoma. Adjusting for censored data by Kaplan Meier analysis, the incidence of cholesteatoma was 2.2% between the ages 5 and 18 years, or 0.2% per year. Acquired cholesteatoma was 3 times more common in cleft lip and palate than cleft palate alone (p=0.002, Kaplan Meier Log-rank survival analysis). Conclusions The rate of acquired cholesteatoma in children with cleft palate is approximately 200 times the baseline rate. Children, especially teenagers, with cleft lip and palate appear to be at significantly higher risk for acquired cholesteatoma than children with cleft palate alone.
International journal of pediatric otorhinolaryngology 02/2013; · 0.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: INTRODUCTION: Similarities between the peripheral auditory and vestibular systems suggest that children with sensorineural hearing loss (SNHL) may demonstrate associated vestibular impairments. The current study examines vestibular function in a previously reported cohort (n = 40) augmented by 113 children with profound SNHL. METHODS: The current study is prospective and cross-sectional with repeated measures. Horizontal canal function was assessed in response to caloric and rotational stimuli. Saccular function was examined using vestibular evoked myogenic potentials (VEMP). One hundred fifty-three children were tested; 119 had unilateral cochlear implants (CIs) at time of testing, and 34 were evaluated before CI. RESULTS: Horizontal semicircular canal function was abnormal in response to caloric stimuli in 50% (69/139), with a proportion (18/69, 26%) reflecting mild to moderate unilateral abnormalities. Severe hypofunction or areflexia occurred in 37% (51/139). Horizontal semicircular canal function in response to rotation was abnormal in 47% (64/139). Bilateral reduction in VOR gain was seen across frequencies in 29% (40/139) and 13% (18/139) demonstrated isolated high-frequency (≥2 Hz) loss. Saccular function was absent bilaterally in 21% (32/135) and unilaterally in 30% (40/135). All children with meningitis (n = 11) and 46% with radiologic cochleovestibular anomalies (n = 31) had horizontal canal dysfunction, whereas 45% and 46%, respectively, displayed saccular dysfunction. Unilateral dysfunction of the horizontal canal or the saccule was equally distributed between the implanted and nonimplanted ear (14:9 and 22:18, respectively), and the differences in proportions were not statistically significant. CONCLUSION: Vestibular end organ dysfunction occurred in half of all children with profound SNHL. Approximately one-third of the subjects displayed severe abnormalities(bilateral and/or severe loss). The likelihood of vestibular end-organ dysfunction is highly dependent on etiology, with meningitis and cochleovestibular anomalies having the highest rates of severe dysfunction.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 01/2013; · 1.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: OBJECTIVES: We asked how thresholds of auditory activity evoked by a recent research cochlear implant, the Nucleus 513, compared with those evoked by previous generations of devices from the same manufacturer. STUDY DESIGN: Prospective repeated measures. SETTING: Tertiary pediatric hospital. PATIENTS: A total of 182 children receiving unilateral or bilateral Nucleus cochlear implants. INTERVENTIONS: Of 182 children, 39 received the N24M straight array, the oldest device in this study, 20 received the N24RCS Contour, the next device released, 57 received the 24RE Freedom, released after the N24RCS, and 66 received the N513 Leap electrode array, the newest device. MAIN OUTCOME MEASURES: Behavioral thresholds and auditory nerve response thresholds were evoked by an apical, mid-array, and basal electrode and measured in 203 ears. RESULTS: In general, auditory nerve thresholds decreased with newer devices. Responses evoked by the mid-array electrode had higher thresholds than responses to the other electrodes in most devices and highest in the operating room for the N513. Apical electrodes evoked the lowest thresholds at the level of the auditory nerve. Auditory nerve response thresholds decreased from the operating room to initial device activation with the 2 newest devices (N24RE and N513) tending to show the largest changes. Behavioral thresholds were at lowest levels for the 2 newest devices studied and, unlike auditory nerve response thresholds, decreased with age for all devices. CONCLUSION: Evolving cochlear implant electrode design significantly affects auditory thresholds, but these changes do not occur uniformly along the array.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 01/2013; · 1.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Tympanoplasty in children poses some different challenges from the same procedure in adults. The aim of the current article is to review 10 important considerations in pediatric tympanoplasty that focus on these differences and help to optimize the chance of successful outcome.
Otolaryngology Head and Neck Surgery 09/2012; · 1.72 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Auriculo-condylar syndrome (ACS) is a rare condition affecting first branchial arch structures. The types of hearing loss and temporal bone findings in ACS have not been reported. We describe a 14-year-old male with constricted pinnae, mandibular dysostosis, glossoptosis, a high-arched palate, hearing loss, and cholesteatoma. Computed tomography imaging demonstrated malleoincudal joint ankylosis. The fused malleoincudal complex was removed during mastoidectomy for cholesteatoma. Electron microscopy and histopathology of the joint suggested the fusion was congenital. This is the first report of ossicular fusion and cholesteatoma in ACS and the most detailed in vivo evidence of disruption of embryogenesis during malleoincudal joint formation. Laryngoscope, 2012.
The Laryngoscope 08/2012; · 1.75 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To establish clinically derived indications for performing canal wall-up or canal wall-down surgery when treating children with cholesteatoma.
Case series with chart review.
Tertiary care academic pediatric otolaryngology practice.
Retrospective review of 420 children who underwent 700 procedures for cholesteatoma between 1996 and 2010.
The canal wall was preserved in 89.5% of cases. Common reasons for removing the canal wall were to provide access to the disease, extensive erosion of key structures, and the desire to avoid further surgery. The mean pure-tone average (PTA) for the canal wall-up group was 30 dB, whereas the canal wall-down group had a mean PTA of 45 dB. A matched-pairs analysis demonstrated that the better performance of the canal wall-up group was independent of preoperative hearing levels. Furthermore, although the presence of the stapes did influence hearing results, the canal wall-up procedure yielded better results even when the condition of the stapes was taken into account. The number needed to treat with canal wall-up to prevent 1 case of hearing loss (ie, mean threshold >30 dB) would be around 6. The need for revision surgery was higher in the canal wall-up group (51%) compared with the canal wall-down group (21%).
In the setting of adequate follow-up and open access to surgical resources, most children with cholesteatoma can be managed with an intact canal wall technique. The authors believe that the better audiometric outcomes and easier postoperative care outweigh the need for revision surgery in this group.
Otolaryngology Head and Neck Surgery 05/2012; 147(2):316-22. · 1.72 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Bilateral cochlear implants (CIs) might promote development of binaural hearing required to localize sound sources and hear speech in noise for children who are deaf. These hearing skills improve in children implanted bilaterally but remain poorer than normal. We thus questioned whether the deaf and immature human auditory system is able to integrate input delivered from bilateral CIs. Using electrophysiological measures of brainstem activity that include the Binaural Difference (BD), a measure of binaural processing, we showed that a period of unilateral deprivation before bilateral CI use prolonged response latencies but that amplitudes were not significantly affected. Tonotopic organization was retained to some extent as evidenced by an elimination of the BD with large mismatches in place of stimulation between the two CIs. Smaller place mismatches did not affect BD latency or amplitude, indicating that the tonotopic organization of the auditory brainstem is underdeveloped and/or not well used by CI stimulation. Finally, BD amplitudes decreased when the intensity of bilateral stimulation became weighted to one side and this corresponded to a perceptual shift of sound away from midline toward the side of increased intensity. In summary, bilateral CI stimulation is processed by the developing human auditory brainstem leading to perceptual changes in sound location and potentially improving hearing for children who are deaf.
Journal of Neuroscience 03/2012; 32(12):4212-23. · 7.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The objectives of this work were to assess inter- and intraobserver variability of different staging systems for tympanic membrane (TM) retraction using otoendoscopy in children at risk of retraction from cleft palate, to compare hearing level with stage of retraction, and to propose optimum characteristics for monitoring TM retraction with endoscopy.
Cross-sectional study.
Endoscopic images of 245 TMs of children with cleft palate (mean age, 13.0 years) were assessed on two separate occasions by six observers using the Sade and Erasmus staging systems for pars tensa retraction and Tos system for pars flaccida retraction. Intra- and interobserver agreements were calculated. Extent of TM retraction was compared with hearing threshold. TMs with middle ear effusion, tympanostomy tubes, or perforation were excluded.
A total of 108 ear drums (44%) were rated as having pars tensa and/or flaccida retraction. Intraobserver agreement was fair to moderate (kappa = 0.3-0.37, P < .001) for the different staging systems and interobserver agreement slight to moderate (0.18-0.41 P < .001). Conductive hearing loss (four-tone average air-bone gap >25 dB HL) was present in 11 ears (15%). No correlation between hearing threshold and retraction stage was found. Isolated tensa retraction onto the promontory increased hearing threshold more than retraction involving the incus (P = .02; analysis of variance).
Endoscopic image capture may provide a clear objective record of TM retraction, but current staging systems have unsatisfactory reliability when applied to such images, and retraction stage correlates poorly with hearing threshold. Modification of retraction assessment to improve validity and clinical relevance is proposed.
The Laryngoscope 02/2012; 122(5):1115-20. · 1.75 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Flat-panel cone-beam computed tomography (CBCT) is able to assess the trajectory of the implanted cochlear implant (CI) array. This is essential to determine specific effects of electrode design and surgical innovations on outcomes in cochlear implantation. CBCT is a non-invasive approach yielding similar data to histopathological analyses, with encouraging potential for use in surgical, clinical and research settings.
To examine the fidelity of CBCT imaging and custom 3D visualization in characterizing CI insertion in comparison to gold standard, histopathological examination.
Eleven human temporal bones were implanted with the 'Straight Research Array' (SRA). Post-insertion, they were imaged with a prototype mobile C-arm for intraoperative CBCT. Post-acquisition processing of low-dose CBCT images produced high-resolution 3D volumes with sub-millimetre spatial resolution (isotropic 0.2 mm(3) voxels). The bones were resin impregnated and sectioned for light microscopic examination. Dimensional electrode characteristics visible in section images were compared with corresponding CBCT images by independent observers.
Overall, CBCT demonstrated adequate resolution to detect: 1) scala implanted; 2) kinking; 3) number of intracochlear contacts; 4) appropriate ascension of the array; and overall confirms ideal insertion. CBCT did not demonstrate adequate resolution to detect reversal of electrode contacts or basilar membrane rupture.
Acta oto-laryngologica 01/2012; 132(4):361-8. · 0.98 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Non-accidental caustic injury is a rare form of child abuse usually secondary to forced ingestion. Caustic injury to the ear most commonly arises from battery lodgement in the external canal. This case series represents the first report of non-accidental caustic injury to previously normal ears resulting in profound sensorineural hearing loss, vertigo with horizontal canal hypofunction and in one patient a severe facial nerve paralysis. Both patients required blind-end sac closure of the injured ear and one required sural nerve interposition combined with transfer of the masseteric branch of the trigeminal nerve to the ipsilateral facial nerve.
International journal of pediatric otorhinolaryngology 01/2012; 76(1):145-8. · 0.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cochlear implants (CIs) electrically stimulate the auditory nerve providing children who are deaf with access to speech and music. Because of device limitations, it was hypothesized that children using CIs develop abnormal perception of musical cues. Perception of pitch and rhythm as well as memory for music was measured by the children's version of the Montreal Battery of Evaluation of Amusia (MBEA) in 23 unilateral CI users and 22 age-matched children with normal hearing. Children with CIs were less accurate than their normal hearing peers (p < 0.05). CI users were best able to discern rhythm changes (p < 0.01) and to remember musical pieces (p < 0.01). Contrary to expectations, abilities to hear cues in music improved as the age at implantation increased (p < 0.01). Because the children implanted at older ages also had better low frequency hearing prior to cochlear implantation and were able to use this hearing by wearing hearing aids. Access to early acoustical hearing in the lower frequency ranges appears to establish a base for music perception, which can be accessed with later electrical CI hearing.
Frontiers in psychology. 01/2012; 3:425.
-
01/2012; , ISBN: 978-85-60209-20-0
-
[show abstract]
[hide abstract]
ABSTRACT: To evaluate the rate of cochlear implant (CI) failure and CI reimplantation (CIri) in our population of children receiving implants by means of a technique that includes device fixation with suture to cortical bone.
Retrospective analysis from January 1990 to June 2010.
Tertiary pediatric hospital.
A total of 971 devices were provided to 738 children (5575 implant-years).
Cochlear implant explants and CIri.
Surgical findings at CIri were assessed by device model. The Pediatric Ranked Order Speech Perception score and the Phonetically Balanced Kindergarten score were used to make comparisons of hearing ability before and after CIri.
Thirty-four patients have undergone CIri in our pediatric center during the past 20 years. Excluding 7 of these patients who received their initial implant at other centers, our rate of CIri was 2.9%. Mean (SD) time to device failure was 61 (43) months. A disproportionately high number of patients (7 of 35 [20%]) requiring CIri had meningitis before implantation. After CIri, children maintained or improved their best speech performance measured before device failure, with only 2 children showing a significant reduction in speech perception after CIri.
A very low rate of failure occurs in children who receive CI devices, and several factors may account for this low rate. Children who develop meningitis before CI appear to be at an increased risk of device failure.
Archives of otolaryngology--head & neck surgery 12/2011; 137(12):1190-6. · 1.92 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To review the clinical findings and treatment algorithms for intracranial complications of acute mastoiditis, such as sigmoid sinus thrombosis, otitic hydrocephalus, intracranial abscess, and otitic meningitis. We also briefly discuss the clinical sequelae of these complications.
Recent changes in the microbiology and treatment paradigms of otitis media have the potential to influence the rates of intracranial complications of mastoiditis; however, evidence supporting a resultant increase in the rates of these complications is lacking.
Antibiotic therapy and myringotomy with ventilation tube placement, with or without mastoidectomy, are the mainstays of treatment for intracranial complications of acute mastoiditis. Adjunct treatment, such as anticoagulation for sigmoid sinus thrombosis, is often used; however, the rarity of these complications makes establishing appropriate levels of evidence to support their use difficult.
Current opinion in otolaryngology & head and neck surgery 09/2011; 19(6):478-85.
-
[show abstract]
[hide abstract]
ABSTRACT: Hypoplasia of the auditory nerve (AN) refers to significant narrowing of the VIIIth cranial nerve which could compromise stimulation of the nerve by electrical pulses delivered from a cochlear implant (CI), thereby hindering activity in other parts of the auditory pathways. To compensate, high current levels or increased charge may be required to elicit auditory perception causing current to spread to other cranial nerves and potentially resulting in unwanted myogenic responses. Deficits in central auditory activity could reduce perception of speech and language. In the present study, we measured auditory brainstem responses in children with and without hypoplasia of the AN to answer the following questions. In children with hypoplastic ANs, (a) can CI stimulation evoke typical patterns of activity from the AN and brainstem?, (b) do brainstem responses change with CI experience?, (c) are evoked responses dependent on the size of the AN pathway?, and (d) does auditory development measured by behavioral tests of speech perception develop more slowly than in peers with normal AN diameter?
Of 807 children using CIs in our program, 20 (2.5%) were identified as having AN hypoplasia using high-resolution computed tomographic scan and/or magnetic resonance imaging. An age-matched control group of children using CIs with normal AN diameter were recruited to compare electrophysiological and behavioral measures. Radiologic imaging was used to measure the diameter of the internal auditory canal (IAC), auditory nerve canal (ANC), and AN. Electrophysiological testing of the evoked compound action potential and auditory brainstem response was performed at CI activation and every 3 mo after initial testing up to 2 yr. Peak latency and waveform morphology were compared between study and control groups. Tests of speech perception and discrimination were attempted every 12 mo after device activation up to 10 yr.
: Hypoplastic AN was identified as moderate to critical stenosis of the IAC, ANC, and AN. Initial electrically evoked compound action potential responses were mostly absent in children with AN hypoplasia. In the time window when electrically evoked auditory brainstem responses would be expected, some responses included single amplitude peaks at normal wave eV latencies, but the majority were abnormal, with peaks at atypical latencies or with no observable wave peaks. All evoked responses were inconsistent over time and did not reflect a typical pattern of auditory brainstem development. Speech perception scores were significantly poorer in the study group compared with controls and did not improve with CI experience. The type of abnormal evoked waveform response was independent of IAC, ANC, or AN diameter and also independent of behavioral outcome measures.
: Evoked responses recorded in CI children with AN hypoplasia indicate a high incidence of nonauditory activity with CI use. The range of abnormal responses was not predicted by the severity of the hypoplastic AN or associated structures. This, along with poorer auditory development compared with peers with normal AN diameters, suggests that children with hypoplasia of the AN are poor candidates for cochlear implantation.
Ear and hearing 07/2011; 33(1):3-18. · 2.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To measure speech detection in noise performance for children with bilateral cochlear implants (BiCI), to compare performance in children with simultaneous implant versus those with sequential implant, and to compare performance to normal-hearing children.
Prospective cohort study.
Tertiary academic pediatric center.
Children with early-onset bilateral deafness and 2-year BiCI experience, comprising the "sequential" group (>2 yr interimplantation delay, n = 12) and "simultaneous group" (no interimplantation delay, n = 10) and normal-hearing controls (n = 8).
Thresholds to speech detection (at 0-degree azimuth) were measured with noise at 0-degree azimuth or ± 90-degree azimuth.
Spatial unmasking (SU) as the noise condition changed from 0-degree azimuth to ± 90-degree azimuth and binaural summation advantage (BSA) of 2 over 1 CI.
Speech detection in noise was significantly poorer than controls for both BiCI groups (p < 0.0001). However, the SU in the simultaneous group approached levels found in normal controls (7.2 ± 0.6 versus 8.6 ± 0.6 dB, p > 0.05) and was significantly better than that in the sequential group (3.9 ± 0.4 dB, p < 0.05). Spatial unmasking was unaffected by the side of noise presentation in the simultaneous group but, in the sequential group, was significantly better when noise was moved to the second rather than the first implanted ear (4.8 ± 0.5 versus 3.0 ± 0.4 dB, p < 0.05). This was consistent with a larger BSA from the sequential group's second rather than first CI.
Children with simultaneously implanted BiCI demonstrated an advantage over children with sequential implant by using spatial cues to improve speech detection in noise.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 06/2011; 32(7):1057-64. · 1.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In our experience, surgical outcomes in children have been excellent with a low complication rate. Our aim in this study was to better understand what aspects of our current surgical technique have been successful with a view to retain those that are beneficial as we proceed with implantation of future devices. Because the receiver-stimulator and overlying skin flap may be more vulnerable to damage in children than adults, we concentrated on issues related to the positioning and security of this part of the implant on the head. Three specific areas of vulnerability were explored in separate experiments. In Experiment 1, we determined the effect of the position of the device on the ability of a child to roll their head without allowing contact between the device and a supporting surface. The 'freeroll' angle was determined for devices position conventionally (back position) and for those in which the device is placed in a more anterior position (up position). In Experiment 2, we studied the retentive capacity of the child's pericranium and measured the displacement force required to dislodge an implant from the bed if retained by the calvarium only. In Experiment 3, we compared the skull curvature of children in whom the device was placed in the back versus the up position. These results inform us as how to best proceed with implantation in children using future devices that have thinner and wider receiver-stimulators.
Cochlear implants international 05/2011; 12 Suppl 1:S14-8.
-
[show abstract]
[hide abstract]
ABSTRACT: Pediatric ossiculoplasty presents the surgeon with a number of unique challenges relating, for example, to timing, choice of graft material, stabilization, and reconstruction. The aim of the current article is to review 10 important considerations in pediatric ossiculoplasty in an effort to maximize outcomes while minimizing complications. Routinely and systematically addressing each of these factors prior to and during ossiculoplasty in every pediatric patient will both optimize and contribute to understanding the hearing results achieved.
Otolaryngology Head and Neck Surgery 04/2011; 144(4):486-90. · 1.72 Impact Factor
