Postoperative Hearing Thresholds Research Articles

Endoscopic butterfly cartilage myringoplasty

Conclusion: Based on the results of this study, it is believed that, in appropriate patients with tympanic membrane perforation, the endoscopic butterfly cartilage myringoplasty can be applied, with a shorter operation time, high graft success rate, and low risk of complications. Objective: The aim of this study was to evaluate the results of the endoscopic butterfly cartilage myringoplasty in terms of the graft success rate and hearing gain. Methods: Forty-five ears of the 42 patients who were subjected to endoscopic butterfly cartilage myringoplasty surgery between January 2013 and December 2014 were included in this study. The archival records of the patients were reviewed retrospectively, evaluating the pre-operative and post-operative hearing results and post-operative graft success rates in the early and late periods. Results: The graft success rates were 97.8% (44/45 ears) and 95.6% (43/45 ears) at the post-operative 1- and 6-month follow-ups, respectively. When the post-operative air conduction hearing thresholds were compared, significant improvement was seen at post-operative 1- and 6-month follow-ups in the hearing thresholds, when compared to the pre-operative levels (p < 0.001).

The occurrence of tinnitus after CI surgery in patients with severe hearing loss: A retrospective study

Objective: An often reported side-effect of a cochlear implant (CI) is suppression of tinnitus. However, induction of tinnitus is also a known complication of CI surgery. To date, it remains unclear why some CI recipients experience larger tinnitus complaints due to CI surgery while most others do not. The goal of this study was to investigate the effect of deterioration of residual hearing due to CI surgery on tinnitus. Design: In this retrospective database study, pre- and postoperative audiometric hearing thresholds were retrieved from patients’ clinical files. Furthermore, tinnitus questionnaires were sent to all patients who fitted inclusion criteria. Study sample: Of the 512 CI patients who were implanted within the last ten years, 197 patients fitted the inclusion criteria and returned the questionnaires. Results: We identified 39 cases (19.8%) who suffered from a newly developed (25) or deteriorated (14) tinnitus following CI surgery. No statistically significant association between perioperative deterioration of hearing thresholds measured by pure-tone audiometry and the development or deterioration of tinnitus was found. Conclusions: There is a small risk for deteriorated residual hearing after cochlear implantation. However, for patients with preoperative residual hearing, there appears to be no increased risk of developing chronic tinnitus after hearing deterioration due to cochlear implantation.

Delayed facial nerve decompression for Bell's palsy.

Incomplete recovery of facial motor function continues to be long-term sequelae in some patients with Bell's palsy. The purpose of this study was to investigate the efficacy of transmastoid facial nerve decompression after steroid and antiviral treatment in patients with late stage Bell's palsy. Twelve patients underwent surgical decompression for Bell's palsy 21-70days after onset, whereas 22 patients were followed up after steroid and antiviral therapy without decompression. Surgical criteria included greater than 90% degeneration on electroneuronography and no voluntary electromyography potentials. This study was a retrospective study of electrodiagnostic data and medical chart review between 2006 and 2013. Recovery from facial palsy was assessed using the House-Brackmann grading system. Final recovery rate did not differ significantly in the two groups; however, all patients in the decompression group recovered to at least House-Brackmann grade III at final follow-up. Although postoperative hearing threshold was increased in both groups, there was no significant between group difference in hearing threshold. Transmastoid decompression of the facial nerve in patients with severe late stage Bell's palsy at risk for a poor facial nerve outcome reduced severe complications of facial palsy with minimal morbidity.

Pediatric myringoplasty: Prognostic factors in surgical outcome and hearing threshold recovery

Conclusions: This study shows as decisive factors the history of tympanostomy tube insertion and surgical approach. The closure of the perforation observed at the 6th post-operative month is almost definitive, without finding significant differences ahead. The myringoplasty can be performed simultaneously in bilateral perforations and in a day-case basis with same success rates. Astatistically significant audiometric improvement area is described, after myringoplasty, undescribed previously in literature. Objectives: The aim of this study was to evaluate prognostic factors in surgical outcome and hearing threshold after myringoplasty, in pediatric age. Methods: A 10-year retrospective review of 142 myringoplasties performed by a single surgeon of the Pediatric ENT Department of 12 de Octubre University Hospital. Multiple prognostic factors were investigated, such as those related to perforation and surgery, contralateral ear status, and pre- and post-operative hearing threshold. Results: The overall rate of closure of the perforation was 74.64%. The re-perforation rate was directly proportional to the number of tympanostomy tube insertion (OR = 1.64). Other determining factors were the surgical approach, the graft position and side. There was a post-operative significant improvement (p < 0.001) insuring that the more affected frequencies, low (125–500 Hz) and high frequencies (4000–8000 Hz), were the more improved after the procedure.

The stability of short-term hearing outcome after stapedotomy: a prospective database study

Conclusion: Current guidelines recommend reporting short-term results of > 12 months after treatment of conductive hearing loss. This study suggests that short-term hearing results after stapedotomy recorded at the 3-month follow-up are without loss of vital information compared with data from the currently recommended > 12-month follow-up. The use of 3-month data in reporting outcome could reduce the bias inherent to the loss to follow-up at 12 months. Objective: To investigate the stability of short-term postoperative hearing after stapedotomy for otosclerosis. Methods: This was a prospective database study; 371 cases with otosclerosis were registered in the database between August 2004 and June 2013. We included the 166 primary cases and 37 revision cases that had attended both follow-ups. Results: The mean changes in postoperative hearing thresholds between the 3-month and 12-month follow-up in both primary and revision cases were minimal and clinically insignificant. In all, 3–5% of primary cases and 14–16% of revision cases experienced a change of ≥ 10 dB for the worse of one or more parameters between follow-ups. Results were also stable when considering a range of traditional success criteria. Other complications following surgery were infrequent and typically resolved long term.

Influence of middle ear mucosal condition on post-tympanoplasty audiologic outcome.

In this study, the association between the middle ear mucosal condition and post-tympanoplasty audiologic outcome was investigated in patients with chronic otitis media without cholesteatoma. One hundred and forty-three patients with chronic otitis media were collected in the Department of Otorhinolaryngology-Head and Neck Surgery at Asan Medical Center between January, 2009 and December, 2011. In the course of tympanoplasty, the status of the middle ear mucosa was divided into normal or abnormal by one surgeon. Pure tone audiometry was performed preoperatively and postoperatively, and post-tympanoplasty tympanogram was also conducted to estimate the condition of middle ear cavity. Of the 143 patients, there were 73 patients with normal middle ear mucosa and 70 patients with abnormal middle ear mucosa around Eustachian tube opening. The mean ABG of subjects with normal middle ear mucosa was 20.1 dB preoperatively, and 9.7 dB postoperatively (p < 0.001). Preoperative mean ABG was 22.4 dB and postoperative mean ABG was 16.4 dB in abnormal middle ear mucosa group (p = 0.137). Postoperative ABGs for 500 and 1000 Hz (7.1, 7.7 dB) in normal middle ear mucosa patients were significantly lower than those (17.2, 19.4 dB) in abnormal middle ear mucosa patients (p < 0.001). There was statistically significant correlation between middle ear mucosa status and post-tympanoplasty audiologic outcomes. The better condition of middle ear ventilation, the better postoperative hearing thresholds revealed after tympanoplasty.

Stapes Surgery Outcomes: The Practice of 35 Years

Stapes Surgery Outcomes: The Practice of 35 Years

Hearing Preservation after Lateral Temporal Bone Resection for Early-Stage External Auditory Canal Carcinoma

Objective: To evaluate postoperative hearing outcomes after lateral temporal bone resection (LTBR) with reconstruction of the external auditory canal (EAC) and conductive function for early-stage EAC carcinoma. Methods: We retrospectively examined patients diagnosed with early-stage EAC carcinoma treated with surgery alone between January 2006 and December 2012. Patients who had postoperative adjuvant chemotherapy and/or radiotherapy were excluded. Patients receiving LTBR in combination with tympanoplasty were divided into two groups based on the reconstruction of the EAC with and without (w/o) split-thickness skin grafts (STSGs). Audiological data included the preoperative hearing thresholds and the most recent postoperative hearing thresholds obtained at least 12 months after surgery. The hearing outcome was evaluated based on pure-tone audiograms using the Committee on Hearing and Equilibrium guidelines of the American Academy of Otolaryngology-Head and Neck Surgery for the evaluation of the results of treatment of conductive hearing loss. The postoperative quality of life (QOL) for patients was evaluated using the Glasgow Benefit Inventory (GBI). Results: All patients (n = 15) achieved disease-free survival without significant morbidity or mortality. When we compared the mean air-bone gaps after surgery, those in the STSG group (n = 8) were found to be significantly lower than those in the w/o STSG group (n = 7; p < 0.001). The success rate for postoperative hearing was 75.0% in the STSG group, which was significantly higher than that in the w/o STSG group (p = 0.014). All patients in the w/o STSG group showed stenosis and closure of the EAC at fewer than 10 months after surgery. In contrast, all patients in the STSG group showed preserved conformation of the new EAC for more than 12 months after surgery. When we compared the mean GBI score between the two groups of patients, the overall and general health scores in the STSG group were found to be significantly higher than those in the w/o STSG group (p = 0.021, p = 0.001). Conclusions: Reconstruction of the EAC using a rolled-up STSG technique in combination with tympanoplasty after LTBR is useful for hearing preservation and the observation of locoregional lesions after surgery, resulting in improved QOL for patients. i 2014 S. Karger AG, Basel

Traumatic ossicular disruption with isolated fracture of the stapes suprastructure: comparison with incudostapedial joint dislocation

Conclusion: More severe high frequency hearing loss, especially at 8 kHz, occurs with fracture of the stapes suprastructure (SSF) compared with isolated incudostapedial joint dislocation (ISD). Successful hearing gain can be achieved in the speech range with appropriate ossicular reconstruction. Objectives: Traumatic SSF is a rare consequence of head trauma. This study aimed to demonstrate the characteristic features of SSF compared with traumatic ISD. Methods: Eighteen patients who suffered from conductive hearing loss after head trauma and were operated from 2000 to 2012 were enrolled. Eight and 10 patients were confirmed to have a traumatic SSF (SSF group) and ISD (ISD group), respectively. The etiology of ossicular disruption, preoperative CT scan of the temporal bone, and intraoperative findings were retrospectively reviewed. Pre- and postoperative hearing was analyzed by both pure tone averages and thresholds at each frequency (0.5–8 kHz). Results: The most common etiologies in the SSF group were fall (n = 3) and direct ear trauma (n = 3), and for those in the ISD group, the most common etiology was traffic accident (n = 6). CT scan showed no evidence of fracture in the SSF group, whereas findings of ossicular dislocation were found in 70% of patients in the ISD group. Hearing outcomes according to the frequencies demonstrated that pre- and postoperative hearing loss at 8 kHz was more severe in the SSF group than in the ISD group. In a comparison of hearing outcomes at each frequency, the postoperative hearing threshold at 8 kHz was higher than for other frequencies. Postoperatively, 63% of the SSF group and 70% of the ISD group obtained an air–bone gap of within 15 dB.

Loop Overlay Myringoplasty versus Medial Myringoplasty: A Comparative Study

Objectives: One of the most important factors in the success of myringoplasty is the size of the perforation. The repair of subtotal and large central perforation is less likely to be successful compared with the repair of small perforations. Loop overlay technique of myringoplasty offers an advantage in these situations and can be a viable alternative. Methods: A prospective controlled study from January 2010 to December 2011 of inactive (mucosal) chronic otitis media with subtotal and large central perforations. Subjects: Forty cases of either sex in the age group of 18-40 years. Pt. B.D.S Post graduate Institute Medical Sciences Rohtak, India, a tertiary care center. Patients were randomly divided into 2 groups of 20 each. Group A underwent medial myringoplasty and Group B Loop overlay myringoplasty. The graft uptake rate and the preoperative and postoperative hearing thresholds in each group were analyzed. Independent variables: Size and location of the perforation, preoperative air bone gap, technique of myringoplasty used. Results: The overall graft take-up rate in group A was 90% and in group B it was 95%. Further, the average postoperative gain in group A was 16.25 dB as compared to 18.5 dB of group B. Conclusions: Loop overlay myringoplasty is better than medial myringoplasty in subtotal and large central perforations.

A comparison of hearing results following stapedotomy under local versus general anesthesia

Advances in operative technique, instrumentation, and prosthesis design in otosclerosis surgery continue since Shea performed the first successful surgery. This is the first analysis to specifically compare post-operative hearing outcomes following stapedotomy surgery performed under local versus general anesthesia. Hearing outcomes were further stratified by comparing conventional perforator and Er:YAG laser ablation perforation techniques. Pre- and post-operative audiograms were retrospectively analyzed together with the method of anesthesia and the perforation technique for all patients with otosclerosis who underwent stapedotomy between 1998 and 2007. Pre-operative individual standard audiometry frequency thresholds (IFTs), air (AC) and bone conduction pure tone averages (PTA), and air bone gaps (ABG) were compared against post-operative results. Differences between pre- and post-operative PTAs and ABGs were compared between patients who received stapedotomy under local versus general anesthesia, as well as for patients who underwent conventional versus Er:YAG laser ablation perforations. Eighty-six patients were identified of which 24 % (n = 21) received local and 76 % (n = 65) received general anesthesia. Post-operative audiograms were available for 84 and 48 patients, respectively. Significant improvements were seen across all groups for standard 4-frequency AC-PTA and ABG and for IFTs up to 3 kHz. No significant difference was seen for IFTs between 4 and 6 kHz. A significant decline in post-operative hearing thresholds was seen at 8 kHz. Significant improvements in PTA and ABG were seen for all groups. There was a trend toward general compared to local anesthesia post-operative hearing results furthermore in combination with conventional perforation technique then with laser technique.

Factors Affecting Success and Results of Cartilage-Perichondrium Island Graft in Revision Tympanoplasty

RESULTS: Thirty-three cases, 14 females and 19 males with mean age 37.5±12.7, were included in the study. Ossiculoplasty was performed in 8 cases, and mastoidectomy was added to tympanoplasty in 12 cases. Tympanic membrane was intact in 29 cases (87.4%) in the 12th postoperative month. Large perforation, adhesive tympanic membrane, and especially hypertrophic middle ear mucosa were found to have negative impact on success of graft (p<0.01). The success of graft in patients with mastoidectomy was lower than without mastoidectomy (p<0.001). Age (p=0.491), gender (p=0.567), surgical approach (p=0.378), and the number of operations (p=0.283) did not contribute to the success of the graft. Average improvement of postoperative air conduction hearing threshold was 13.2±5.5 dB, and average decrease in air bone gap was 11.7±5.5 dB. CONCLUSION: Postoperative closure rate of the tympanic membrane was high and audiologic improvement was satisfactory with cartilage-perichondrium island graft in revision tympanoplasty. Cartilage-perichondrium island graft may be preferred for reconstruction of the tympanic membrane because of its resistance to inflammation and poor feeding in revision tympanoplasty.

Comparison of the anatomic and hearing outcomes of cartilage type 1 tympanoplasty in pediatric and adult patients

As a graft material cartilage produces an excellent anatomical result with a low risk of re-perforation. However, there is a controversy among surgeons regarding its sound conduction properties, due to the thickness and stiffness of the cartilage. The aim of this study was to evaluate results of cartilage type I tympanoplasty and to compare anatomic and audiologic results in pediatric and adult patients. Patients with chronic otitis media who underwent cartilage type I tympanoplasty were evaluated retrospectively. Patient age, gender, pre and postoperative hearing levels, surgical technique and postoperative complications were recorded. Hearing outcomes of the patients were measured with tonal audiometry by comparing the pre and postoperative hearing threshold calculated at 0.5, 1, 2, and 4 kHz. Graft success rates and hearing outcomes of the pediatric and adult patients were compared. Of the 136 patients included in the study, 58 were male and 78 were female. The average age was 25.03. Forty-five patients were ≤16-year old and 91 patients were >16-year old. Intact graft was determined in 41 of 45 pediatric patients and 85 of 91 adult patients at the last follow-up visit. The overall graft success rate was 92.6 %. The mean pre and postoperative pure-tone average was 34.8 ± 8.5 and 23.4 ± 9.1 dB in adult patients, and 30.6 ± 7.7 and 17.8 ± 7.8 dB in pediatric patients. Cartilage graft provides a quite satisfactory anatomical result and perfect stability. Hearing outcomes of cartilage tympanoplasty are also acceptable in both children and adult patients.

Medio‐Lateral Myringoplasty versus Medial Myringoplasty: A Comparative Study

Objectives:One of the most important factors in the success of myringoplasty is the size of the perforation. The repair of subtotal and large central perforation is less likely to be successful compared with the repair of small perforations. Moreover anterior tympanic membrane is less vascular and the re‐peroration rates are higher in this part. Medio‐lateral myringoplasty offers an advantage in both of these situations and can be a viable alternative to conventional underlay myringoplasty.Methods:A prospective controlled study was undertaken from January 2008 to December 2010. Disease/ condition studied: Inactive (mucosal) chronic otitis media with large central, subtotal and anterior perforations. Subjects Forty cases of either sex in the age group of 18‐40 years. Setting: Pt. B.D.S Post graduate Institute Medical Sciences Rohtak, a tertiary care center. Patients were randomly divided into two groups of twenty each. Group A underwent medial myringoplasty and group B underwent medio‐lateral myringoplasty. The graft uptake rate and the preoperative and postoperative hearing thresholds in each group were analyzed. Independent variables: Size and location of the perforation, preoperative air bone gap and technique of myringoplasty used.Results:The overall graft uptake in group A was 80% as compared to graft uptake of 95% in group B. Further, the average postoperative gain in group A was 14 dB as compared to 17.5 dB of group B.Conclusions:Medio‐lateral myringoplasty is better than medial myringoplasty in subtotal and large central perforations.

Tympanomastoidectomy: Comparison between canal wall-down and canal wall-up techniques in surgery for chronic otitis media.

Summary Introduction: Chronic otitis media (COM) is an inflammatory condition associated with otorrhea as well as large and persistent perforations of the tympanic membrane in some cases. COM can also lead to cholesteatoma. Surgical treatment with canal wall-down and canal wall-up tympanomastoidectomy is considered for both types of illness. The choice of technique is controversial and is dependent on several factors, including the extent of disease. Objective: We aimed to evaluate surgical outcomes in COM patients with and without cholesteatoma treated with canal wall-down and canal wall-up tympanomastoidectomy. Disease eradication and post-operative auditory thresholds were assessed. Method: Patient records from the otorhinolaryngology department of a tertiary hospital were assessed retrospectively. Results: Patients who underwent canal wall-up tympanomastoidectomy had a higher rate of revision surgery, especially those with cholesteatoma. However, there were no statistically significant differences in post-operative hearing thresholds between the two techniques. Conclusion: The canal wall-down technique is superior to the canal wall-up technique, especially for patients with cholesteatoma.

Factors affecting hearing improvement following successful repair of the tympanic membrane

The main aim of tympanic membrane repair is the elimination of chronic or intermittent aural discharge. Hearing improvement may or may not occur following a technically successful operation. This study entailed a retrospective analysis of prospectively collected data from 203 operations that resulted in an intact tympanic membrane 6 months after surgery. Complete hearing data were available for 169 operations on 160 patients. Of these, 53 per cent resulted in closure of the air-bone gap to within 10 dB, and 54 per cent of cases had post-operative hearing thresholds of at least 30 dB. The mean hearing change after surgery was +8.3 dB. Multiple regression analysis indicated that hearing improvement was more likely in large compared with small perforations. Smaller hearing gains occurred in ears with erosion of the stapes arch and/or fixation of the stapes, as well as in those with active discharge at the time of surgery and in revision cases. Greater hearing improvement can be expected following successful repair of perforations involving more than 50 per cent of the drum area. Poorer results are likely to occur in ears with additional middle-ear pathology and in revision cases.

Tympanosclerosis – a Beginner’s Worry: a Case Series and Review of Literature

Introduction: The aim of the present study is to study cases of tympanosclerosis retro-prospectively in regards to their clinical presentation and also their surgical management. Materials & Methods: 73 cases of tympanosclerosis were studied over a period of two years. Patients were also classified as those operated by the consultant surgeon and the resident surgeon. Results: The surgical procedure commonly carried out was Type 1 Tympanoplasty, with no significant difference seen with partial or complete removal of tympanosclerotic plaques with regards to the graft uptake or the post operative hearing thresholds. A difference was observed in the number of complications in cases operated by the consultant surgeon as against the resident surgeon. Conclusion: Though the symptoms of tympanosclerosis may not be a dramatic it does pose a significant dilemma especially to a novice otologist with regards to its complete resection.

Ossiculoplasty in Missing Malleus and Stapes Patients

To present the preliminary results of new malleus replacement prosthesis combined with a total ossicular prosthesis in middle ear reconstruction in patients missing the malleus and stapes. Prospective experimental and nonrandomized clinical study. Tertiary referral center. An original titanium malleus replacement prosthesis (MRP) was designed to be inserted into the external auditory canal and to replace a missing malleus for various middle ear pathologies. The MRP was tested experimentally and clinically. The vibratory properties of the new prosthesis were measured using laser Doppler vibrometry. Ninety patients with missing malleus and stapes, undergoing 92 ossicular reconstructions were enrolled in this study from September 1994 to March 2012. Comparative analyses were made between a group of 34 cases of ossicular reconstructions with total prosthesis (TORP) positioned from the tympanic membrane to the stapes footplate (TM-to-footplate assembly) and a group of 58 cases of ossicular reconstructions with TORP positioned from a newly designed malleus replacement prosthesis (MRP) to the stapes footplate (MRP-to-footplate assembly). Preoperative and postoperative audiometric evaluation using conventional audiometry, that is, air-bone gap (ABG), bone-conduction thresholds (BC), and air-conduction thresholds (AC) were assessed. Experimentally, the vibratory properties of the MRP are promising and remain very good even when the MRP is cemented into the bony canal wall mimicking its complete osseous-integration, if this were to occur. This finding supports the short-term clinical results as in the TM-to-footplate group; the 3-month postoperative mean ABG was 23.3 dB compared with 12.5 dB in the MRP-to-footplate group (difference, 10.8; 95% confidence interval, 4.0-17.6); 37.0% of patients from the TM-to-footplate group had a postoperative ABG of 10 dB or less, and 48.1% of patients had a postoperative ABG of 20 dB or less, as compared with 58.1% and 79.1%, respectively, in the MRP-to-footplate group. The average gain in AC was 11.0 dB in the TM-to-footplate group as compared with 21.3 dB in the MRP-to-footplate group (difference, -10.3; 95% confidence interval, -18.2 to -2.4). The results of this study indicate that superior postoperative hearing thresholds could be achieved using a MRP-to-footplate assembly, compared with a TM-to-footplate assembly in patients with an absent malleus undergoing ossiculoplasty. The postoperative AC thresholds, after 3 months and 1 year, are significantly lower in patients treated with the MRP-to-footplate assembly.

Cartilage graft or fascia in tympanoplasty in patients with low middle ear risk index (anatomical and audological results)

The aim of this study was to compare anatomic and audiological results of cartilage graft with temporal fascia graft in type 1 tympanoplasty patients with low middle ear risk index (MERI). In this retrospective study, 63 patients that underwent type 1 tympanoplasty with chondroperichondrial island graft between July 2009 and November 2010 were compared with 45 patients in whom temporal muscle fascia was used. Patients in both groups had low MERI values varying between 1 and 3. Five and nine patients underwent masteidectomy in cartilage and fascia group, respectively. Mean duration of follow-up was 11.9±3.7 (5-17) months. Mean value was calculated at pre-operative and post-operative hearing threshold 0.5, 1, 2, 4kHz, and air bone gap (ABG) gain was compared in both cartilage and fascia groups. when pre-operative and post-operative ABG gain were compared, significant decrease was seen in ABG levels (p<0.001). However, no significant difference was seen in ABG gain values (p=0.608), which was 10.1±7.00dB in cartilage group and 10.8±5.38dB in fascia group. In both groups, age, sex, and the addition of mastoidectomy procedure had no significant effect on ABG gain and success. Cartilage is a graft material that may be preferred without concern about the effects on hearing results, especially, in patients with low MERI values. The addition of mastoidectomy had no impact on the outcome of operation and audiological results. However, further studies with larger case series may be carried out to further clarify the issue.

Cochlear dysfunction in patients with acute hypothyroidism

The effect of acute hypothyroidism on the cochlear function was studied prospectively, in a group of 52 patients with thyroid carcinoma who underwent total thyroidectomy. All patients were examined before surgery and 6-8weeks postoperatively. During this period there was no replacement with levothyroxine and the magnitude of thyroxin depletion was monitored by serum thyroid-stimulating hormone levels. Pure-tone audiometry, tympanometry and transiently evoked otoacoustic emissions were performed. A group of healthy volunteers of similar age and sex were used as controls. Tympanograms were normal, either on initial or on repeat testing. Audiometry showed elevation of all postoperative hearing thresholds, whereas the thresholds varied significantly across frequency. Transiently evoked otoacoustic emission testing showed response signal-to-noise ratios lower in the postoperative session (hypothyroid state) than in the preoperative session on all measured frequencies. Emission levels varied significantly across frequency, with maximum response observed at 2kHz. Comparison of significant pure-tone and otoacoustic emission shifts for individual ears showed more ears affected in otoacoustic emission testing, indicating subclinical involvement. Comparing hearing thresholds and otoacoustic emission levels between patients and controls showed significant differences on postoperative testing. It may be thus concluded that acute hypothyroidism causes elevation of hearing thresholds in humans and to a greater degree subclinical damage of the cochlear function.