Pupillary responses in normal subjects following auditory stimulation

To clarify pupillary responses of humans following auditory stimuli, we studied both eyes of 61 normal subjects using a computed pupillograph. Unilateral auditory stimulation elicited pupillary dilatation in all cases. Pupillary responses were classified according to duration as being either “long” or “short”. The duration of dilatation was 1530±320 ms (mean±SD) in the longlasting group (n=45) and 850±250 ms in the short-lasting group (n=16). The latency time for dilatation was 460±80 ms. Both eyes of each subject showed the same response. Two drops of 10% guanethidine, a sympathetic blocking agent, were applied to one eye of 3 subjects. Although the early phase of dilatation was barely affected, the late phase was inhibited, as seen in long-lasting dilatation. The short-lasting response was unaffected. We conclude that the long-lasting response consists of an early pupillary dilatation due to inhibition of parasympathetic nervous activity and a late dilatation due to excitation of sympathetic activity. The short-lasting response is produced only by inhibition of the parasympathetic component.     

Profiles of resting potentials across the stria vascularis in kanamycin-deafened guinea pigs

The resting potentials of the marginal cells in the stria vascularis of the guinea pig were determined from changes in the combined electrode-tissue resistance of the electrode. The resistance of the electrode was 45.5±16.0 MΩ (n=20) before penetration of the stria vascularis and 46.7±17.3 MΩ (n=20) after penetration. The resistance drops across the luminal membrane of the marginal cells were 46.0±22.6 MΩ (n=12) in kanamycin-deafened guineal pigs and 54.5±33.1 MΩ (n=9) in normal guinea pigs. The endocochlear potential (EP) and resting potentials in the marginal cells were 90.1±6.0 mV (n=14) and 70.4±11.3 mV (n=14) in kanamycin-deafened guinea pigs and 84.8±5.1 mV (n=29) and 74.7±11.7 mV (n=29) in normal guinea pigs. The resting potentials in the marginal cells decreased gradually and were approximately 0 mV around 20 min after anoxia in both kanamycin-deafened and normal guinea pigs. These changes were comparable to those of EP in kanamycin-deafened guinea pigs during anoxia. The mechanism of the EP in kanamycin-deafened guinea pigs is discussed.     

The effect of partial superficial parotidectomy on amplitude,latency and threshold of facial nerve stimulation

The aim of this study is to assess the effect of partial superficial parotidectomy and facial nerve dissection to electrophysiologic parameters of intraoperative facial nerve monitoring such as nerve stimulation threshold, stimulus amplitude and latency. Twenty-five patients who underwent partial superficial parotidectomy for benign parotid gland mass were included in the study. After the identification of the facial nerve main trunk, minimum stimulation threshold, latencies and amplitudes of the orbicularis oculi (electrode 1) and orbicularis oris (electrode 2) electrodes at 0.50 milliamperes (mA) were recorded. All of the recordings were repeated after the completion of parotidectomy. Median nerve dissection duration was calculated and size of the tumors was measured during macroscopic pathology. The median minimum nerve stimulation threshold was 0.15 mA [interquartile range (IQR) = 0.05] before and 0.15 mA (IQR = 0.08) after the parotidectomy (p = 0.02). Median nerve dissection duration was 49 min (IQR = 38). Median amplitude and latency in electrode 1 before and after the facial nerve dissection were 322 millivolts (mV) (IQR = 330), 370 mV (IQR = 370) (p = 0.02), 3 milliseconds (ms) (IQR = 1) and 4 ms (IQR = 2) (p = 0.05), respectively. Median amplitude and latency in electrode 2 before and after the facial nerve dissection were 396 mV (IQR = 275), 365 mV (IQR = 836) (p = 0.86), 3 ms (IQR = 1.5) and 4 ms (IQR = 1.5) (p = 0.17), respectively. Minimal nerve stimulation threshold and amplitude of electrode 1 were affected by facial nerve dissection among the electrophysiologic parameters (p = 0.02 and p = 0.02). Of the electrophysiological parameters only the latency of electrode 2 was significantly correlated with tumor size (p = 0.03). Besides, none of the parameters were predictive for a possible postoperative facial nerve dysfunction regarding superficial partial parotidectomy.     

Intralabyrinthine schwannomas

Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss and vertigo. In an own case series of 12 patients, 6 tumors showed an intracochlear, 3 an intravestibular, 1 a transmodiolar including the cerebellopontine angle (CPA), 1a transotic including the CPA, and 1 a multilocular location. The tumors were removed surgically in 9 patients, whereas 3 patients decided for a “wait-and-test-and-scan” strategy. Of the surgical patients, 3 underwent labyrinthectomy and cochlear implant (CI) surgery in a single-stage procedure; 1 patient had extended cochleostomy with CI surgery; 3 underwent partial or subtotal cochleoectomy, with partial cochlear reconstruction and CI surgery (n = 1) or implantation of electrode dummies for possible later CI after repeated MRI follow-up (n = 2); and in 2 patients, the tumors of the internal auditory canal and cerebellopontine angle exhibiting transmodiolar or transmacular growth were removed by combined translabyrinthine–transotic resection. For the intracochlear tumors, vestibular function could mostly be preserved after surgery. In all cases with CI surgery, hearing rehabilitation was successful, although speech discrimination was limited for the case with subtotal cochleoectomy. Surgical removal of intracochlear schwannomas via partial or subtotal cochleoectomy is, in principle, possible with preservation of vestibular function. In the authors’ opinion, radiotherapy of ILS is only indicated in isolated cases. Cochlear implantation during or after tumor resection (i. e., as synchronous or staged surgeries) is an option for hearing rehabilitation in cartain cases and represents a therapeutic approach in contrast to a “wait-and-test-and-scan” strategy.     

A 16-year experience in treating thyroglossal duct cysts with a “conservative” Sistrunk approach

Although Sistrunk operation is the standard method to treat thyroglossal duct cyst, the reported recurrence rates after a “classic” or “modified” Sistrunk procedure still varied from 0 to 15.8 %, indicating the existence of some technical uncertainties. While simple cystectomy has been recognized as the most important prognostic factor predicting thyroglossal duct cyst recurrence, whether other clinico-pathological parameters also affect disease recurrence has not been well studied. We retrospectively reviewed the medical records of all patients who underwent thyroglossal duct cyst surgery between June 1998 and June 2014 at our institution. Among the 180 primary patients, 160 patients received a “conservative” Sistrunk operation, while the remaining 20 patients received simple cystectomy only. Five patients (2.8 %, 5/180) had recurrence. Four of them received simple cystectomy while 1 had “conservative” Sistrunk operation. In univariable analysis, age (p = 0.02), history of previous infection (p = 0.004) and the type of resection (p = 0.001) were significantly correlated with disease recurrence. In multivariable analysis, the type of resection turned out to be the most important factor (p = 0.03) related to recurrence. In the most parsimonious model selected by backward elimination, both history of infection (p = 0.048) and the type of resection (p = 0.02) were important predictors of postoperative recurrence. Our results demonstrated that a “conservative” Sistrunk approach could provide a comparably low recurrence rate (0.6 %, 1/160) in dealing with primary thyroglossal dust cysts. Routine dissection of suprahyoid tissue may not be imperative. Overall, the type of resection and history of infection are the most important predictors of recurrence for thyroglossal duct cyst.     

The prognostic significance of β-catenin,cyclin D1 and PIN1 in minor salivary gland carcinoma: β-catenin predicts overall survival

Minor salivary gland carcinoma is a rare and heterogeneous type of cancer. Molecular prognostic and predictive markers are sparse. The aim of this study was to identify new prognostic and predictive markers in minor salivary gland carcinoma. 50 tissue samples of carcinomas of the minor salivary glands (adenoid cystic carcinoma n = 23, mucoepidermoid carcinoma n = 12, adenocarcinoma n = 10, carcinoma ex pleomorphic adenoma n = 2, salivary duct carcinoma n = 1, clear cell carcinoma n = 1, basal cell carcinoma n = 1) were immunohistochemically stained for β-catenin, cyclin D1 and PIN1. Expression patterns were analyzed and correlated to clinical outcome of 37 patients with complete clinical data. High expression of membranous β-catenin was linked to significantly better overall survival in patients with adenoid cystic carcinoma (log rank test, χ² = 13.3, p = .00397, Bonferroni corrected p = .024). PIN1 and cyclin D1 did not show any significant correlation to patients’ clinical outcome. Expression of β-catenin in adenoid cystic carcinoma of the minor salivary glands significantly correlates with better overall survival. Hence, evaluation of β-catenin might serve as a clinical prognostic marker.     

Protective effects of resveratrol on cisplatin-dependent inner-ear damage in rats

Cisplatin is a common chemotherapeutic agent used in many solid and hematologic malignancies. The main unwanted effect of cisplatin is ototoxicity, for which no standard treatment has been reported. The present study examined the protective efficacy of resveratrol on cisplatin-dependent ototoxicity through an experimental model. Fifteen rats were randomized into three groups. Group 1 (control group) (n = 5) received intraperitoneal (i.p.) 15 mg/kg cisplatin; group 2 (resveratrol group) (n = 5) received i.p. 100 mg/kg resveratrol, followed by i.p. 15 mg/kg cisplatin; group 3 (n = 5) served as a vehicle group and received i.p. 1 ml dimethyl sulfoxide. All rats underwent the auditory brainstem response (ABR) test before and 72 h after the treatment. Pretreatment ABR values of the groups were not significantly different. The pretreatment hearing threshold values of the groups were 30 ± 6.60 and 28.5 ± 5.29 dB in groups 1 and 2, respectively (p > 0.05). The post-ABR-I and post-ABR-IV values were, respectively, 1.41 ± 0.18 and 5.83 ± 0.16 ms in the control subjects and 1.19 ± 0.22 and 4.58 ± 0.27 ms in the study group. The ABR-I and ABR-IV durations in rats treated with resveratrol were significantly shorter (p < 0.01). A comparison of threshold values shows that the resveratrol-treated rats had significantly lower values than the control rats. After cisplatin injection, ABR I–IV intervals were compared among the groups. The ABR I–IV interval duration was 4.42 ± 0.16 ms in the control group, while the resveratrol-treated rats showed a significantly shorter ABR I–IV interval duration of 3.49 ± 0.27 ms (p < 0.001). Resveratrol attenuated cisplatin-dependent inner-ear damage, as shown by the ABR-I, ABR-IV, ABR I–IV interval, and hearing threshold values. Our results suggest that this natural antioxidant may be effectively used in reducing the unwanted effects of cisplatin on the ear physiology of patients, particularly those undergoing chemotherapy.     

Cochlear implantation through the round window with a straight slotted electrode array: optimizing the surgical procedure

The question addressed here is how optimizing the quality of insertion through the round window with the lower morbidity, when using a straight and slotted electrode array of regular length. This retrospective analysis includes all cases implanted with a cochlear implant Digisonic SP (Neurelec-Oticon Medical) since 2004. We checked the operative charts, the depth of insertion, and the follow-up. For comparisons, contingency tables were used and a Chi-square test was performed. A p value <0.05 was considered significant. 126 cases of patients with non-malformed cochleas were implanted through the round window. The mean age was 53.8 ± 16.2 for adults and 3.6 ± 2.6 for children (24 cases). The mean follow-up was 33 ± 22 months. The straight electrode array had either a square or a soft pointed tip (n = 84). Full insertion was achieved in 79 out of 84 cases with a soft tip vs. 18 out of 42 square tips (χ² = 41.41, DOF = 1, p < 0.0001). Two cases were stuck at the round window niche by a prominent crista fenestrae. In all cases but one, the chorda tympany was preserved. In one case, a misrouting to the vestibule required a revision surgery. Implantation through the round window with a straight and slotted electrode array with a soft tip (Digisonic SP, Neurelec-Oticon Medical) can lead to a full insertion in 94 % of cases. Drilling out a prominent crista fenestrae is recommended.     

Distortion-Product Otoacoustic Emission Measured Below 300 Hz in Normal-Hearing Human Subjects

Physiological noise levels in the human ear canal often exceed naturally low levels of otoacoustic emissions (OAEs) near the threshold of hearing. Low-frequency noise, and electronic filtering to cope with it, has effectively limited the study of OAE to frequencies above about 500 Hz. Presently, a custom-built low-frequency acoustic probe was put to use in 21 normal-hearing human subjects (of 34 recruited). Distortion-product otoacoustic emission (DPOAE) was measured in the enclosed ear canal volume as the response to two simultaneously presented tones with frequencies f ₁ and f ₂. The stimulus–frequency ratio f ₂/f ₁ was varied systematically to find the “optimal” ratio evoking the largest level at 2 f ₁?f ₂ frequencies 87.9, 176, and 264 Hz. No reference data exist in this frequency region. Results show that DPOAE exists down to at least 87.9 Hz, maintaining the bell-shaped dependence on the f ₂/f ₁ ratio known from higher frequencies. Toward low frequencies, however, the bell broadens and the optimal ratio increases proportionally to the bandwidth of an auditory filter as defined by the equivalent rectangular bandwidth. The DPOAE phase rotates monotonously as a function of the stimulus ratio, and its slope trend supports the notion of a lack of scaling symmetry in the apex of the cochlea.     

Prognostic factors of locally invasive well-differentiated thyroid carcinoma involving the trachea

To report our experience with tracheal invasive thyroid carcinoma with emphasis on clinical characteristics and treatment modalities, and to identify the prognostic factors for tracheal invasive thyroid carcinoma. Totally 1919 patients underwent surgical extirpation of thyroid cancer from 1990 to 2010. Among them, 65 patients had well-differentiated thyroid cancer with tracheal invasion. The incidence was higher in male and older patients. Patients were treated with tracheal shave excision (n = 18), tracheal resection (n = 37) and total laryngectomy (n = 10). Locoregional recurrence occurred in 39 patients, and metastasis occurred in 25 patients. Simultaneous involvement of the trachea and the esophagus was associated with locoregional recurrence (p = 0.039) in univariate analysis, but not confirmed by multivariate analysis. There was significant difference in the disease-specific survival (DSS) according to laryngeal involvement (p = 0.002). All the patient in the shave excision group survived until the end of the study period. Although it is categorized in same classification of T4a, simultaneous involvement of the trachea and the esophagus showed higher locoregional recurrence and laryngeal involvement showed lower DSS. Despite the invasion of thyroid cancer into the adjacent aerodigestive tract, many patients showed long survival when they underwent appropriate surgery.     

Glutaminolysis and carcinogenesis of oral squamous cell carcinoma

Glutaminolysis is a crucial factor for tumor metabolism in the carcinogenesis of several tumors but has not been clarified for oral squamous cell carcinoma (OSCC) yet. Expression of glutaminolysis-related solute carrier family 1, member 5 (SLC1A5)/neutral amino acid transporter (ASCT2), glutaminase (GLS), and glutamate dehydrogenase (GLDH) was analyzed in normal oral mucosa (n = 5), oral precursor lesions (simple hyperplasia, n = 11; squamous intraepithelial neoplasia, SIN I–III, n = 35), and OSCC specimen (n = 42) by immunohistochemistry. SLC1A5/ASCT2 and GLS were significantly overexpressed in the carcinogenesis of OSCC compared with normal tissue, while GLDH was weakly detected. Compared with SIN I–III SLC1A5/ASCT2 and GLS expression were significantly increased in OSCC. GLDH expression did not significantly differ from SIN I–III compared with OSCC. This study shows the first evidence of glutaminolysis-related SLC1A5/ASCT2, GLS, and GLDH expression in OSCC. The very weak GLDH expression indicates that glutamine metabolism is rather related to nucleotide or protein/hexosamine biosynthesis or to the function as an antioxidant (glutathione) than to energy production or generation of lactate through entering the tricarboxylic acid cycle. Overcoming glutaminolysis by targeting c-Myc oncogene (e.g. by natural compounds) and thereby cross-activation of mammalian target of rapamycin complex 1 or SLC1A5/ASCT2, GLS inhibitors may be a useful strategy to sensitize cancer cells to common OSCC cancer therapies.     

Use of granules of biphasic ceramic in rehabilitation of canal wall down mastoidectomy

The objective of this study is to evaluate the anatomical and functional results of rehabilitation of canal wall down (CWD) mastoidectomy using granules of biphasic ceramic. This is a study design retrospective in a tertiary referral centre Fifty-seven patients (59 ears) operated on between 2006 and 2010 of mastoid obliteration with granules of biphasic ceramic (TricOs^®, Maurepas, France) have been included (55 revisions and 4 first surgeries). Forty-six patients presented already a CWD mastoidectomy. The mean pre-operative bone conduction (BC) was 29 ± 3.4 dB (mean ± SEM) and mean air conduction (AC) was 57 ± 3.2 dB. Cholesteatoma was found in 33 cases. All but seven cases had post-operative otoscopy examination at 1, 3, 6 months, and 1 year postoperative with a CT scan and pure tone audiometry. Mean follow-up was 14 ± 1.8 months (3–35). At one-year follow-up (n = 52), 47 cases (90 %) presented well-healed external auditory canal. Five cases (10 %) of uncovered granules without sign of infection of external auditory canal skin were observed. Mean post-operative threshold was 25 ± 1.8 and 46 ± 1.9 dB for BC and AC , respectively (n = 47). CT scan (n = 42) showed no opacity suggesting residual disease within or behind obliteration. Mastoid obliteration with granules of biphasic ceramic is a safe and effective procedure that allows restoration of a near normal external auditory canal.     

Nasal congestion after visual sexual stimulation with and without sildenafil (Viagra<Superscript>®</Superscript>): a randomized placebo-controlled study

Sildenafil (Viagra^®) is a selective phosphodiesterase type 5 inhibitor (PDE5-I) approved for treatment of erectile dysfunction. Although relatively well-tolerated, sildenafil is associated with undesired effects including headache, flushing, dyspepsia, nasal congestion, and visual disturbances. In the present study we explored the impact of sildenafil on nasal airway parameters in young potent men. Eleven men (age 26.0 ± 1.8 years) with normal BMI (25.7 ± 0.5) and without nasal respiratory disorders were enrolled in a double-blind, crossover study. All men underwent evaluation of systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), SpO₂%, acoustic rhinometry, and nasal endoscopy before and after placebo or sildenafil (50 mg) plus visual sexual stimulation (VSS). Nasal examination was performed using 0° rigid telescopes, 4 mm in diameter. A Student’s t test was used for direct comparisons, while the Kruskal–Wallis test (K–W) was utilized for multiple comparisons. After administration of sildenafil plus VSS, the minimum cross sectional area (MCA) was significantly lower that observed with either placebo (P = 0.03) or sildenafil alone (P = 0.003). However, the post-stimulation values did not demonstrate any significant differences among the different treatment arms (P = 0.48; DF = 2; K–W test). In contrast, endonasal volume (VOL) was significantly lower after sildenafil + VSS (P = 0.01), but not after placebo + VSS (P = 0.18). None of the other parameters monitored showed any significant variations. Rhinoscopy showed a characteristic increase of the volume of the inferior turbinates, with subjective differences between placebo and sildenafil. These preliminary results suggest that sildenafil reduces nasal volume, and that sexual stimulation may decrease nasal airflow by itself.     

Randomised,multi-centre study of the usefulness of the heat and moisture exchanger (Provox HME<Superscript>®</Superscript>) in laryngectomised patients

This study included 60 patients (30 in Nice and 30 in Reims), who were randomised between a control group that used no device of this type and a group equipped with the Provox HME^®. After 3 months of using the device, a notable improvement was found which was statistically significant with regard to cough (P = 0.00174) and to bronchorrhoea (P = 0.0031), and very close to achieving significance with regard to breathing effort. An overall improvement in the prosthetic (tracheo-oesophageal) voice was found in the 21 patients using the HME^® and a voice prosthesis for all of the parameters studied. The device was used daily by 80% of the patients of whom 42% used it day and night at the end of the 3 months. Seven patients suffered from minor cutaneous intolerance (of whom 6 had received radiation therapy), which did not require the use of the HME^® to be abandoned (PC). After 3 months, patients were asked the following questions: “Do you feel any improvement?”: 92% of affirmative answers; “Are you breathing better?”: 88% of affirmative answers; “Are you speaking more easily?”: 81% had experienced speech improvement. The general adaptation to the device was judged to be satisfactory for 95% of the patients after 3 months. The results of this randomised study show an improvement in the pulmonary symptoms and in the prosthetic voice after 3 months of using Provox HME^®. This light and easy-to-use device appears to us to afford a significantly improved quality of life for laryngectomees and should be offered systematically during functional rehabilitation of these patients.     

Noise impairment in the guinea pig. I. Changes in electrical evoked activity along the auditory pathway

Changes in the cochlear microphonics (CM), auditory nerve action potential (AP), and evoked responses from the inferior colliculus (IC-ER) and auditory cortex (AC-ER) of the guinea pig were assessed after exposure to white noise of 115 dB for 30 min. Both continuous and intermittent (200 ms noise and 200 ms pause) exposures were used. In comparison with the pre-exposure level, CM isopotential curves were shifted by 1.1 ±0.5 dB ($\text{x}\text{?}\text{± S.E.}$) on the average in the range of 0.5–8 kHz (recorded at the round window). The amplitude-intensity function of the click-evoked auditory nerve action potential decreased by 8.4 ± 1.2 dB, that of the inferior colliculus evoked response by 20.9 ±3.7 dB, and the amplitude-intensity function of the auditory cortex evoked potential decreased by 6.2 ± 4.7 dB. A similar reduction in the amplitude was found after both continuous and intermittent noise exposure. In contrast to the decrease in amplitudes of evoked potentials, the latency-intensity functions of the individual waves of potentials evoked along the auditory pathway did not change when compared at the same click intensity before and after the exposure. The results suggest that individual auditory nuclei are impaired by the noise to different extents and that the impairment does not increase linearly up to the auditory cortex.     

Einfluss des Hörens auf die vestibulospinale Kontrolle bei gesunden Probanden

Background

Balance control is based on multisensory interaction. In addition to vestibular, proprioceptive and visual information, it seems that auditory input also plays an important role.

Objectives

The aim of the study was to investigate the effect of hearing on vestibulospinal coordination and to obtain deeper knowledge about mechanisms of audiovestibular interaction.

Materials and methods

In normal hearing, healthy subjects who performed the Unterberger (Fukuda) stepping test with and without frontal presentation of noise, the distance of displacement, the angle of displacement and the angle of rotation were measured by means of ultrasound based cranio-corpo-graphy (CCG). Additionally, subjective estimation of the effect of auditory input was compared to objective test results.

Results

In the noise condition, there was a significant improvement in the distance of displacement (mean with noise 66.9?cm?±?33.5 standard deviation, SD, mean without noise 77.0?cm?±?32.7 SD, p?<?0.001) and in the angle of rotation (mean with noise 14.2°?±?10.1 SD, mean without noise 28.3°?±?20.2 SD, p?<?0.001), while no difference was found within the conditions regarding the angle of displacement (mean with noise 29.1°?±?33.5 SD, mean without noise 30.0°?±?34.0 SD, p?=?0.641). Side-specific analysis revealed a positive correlation between angle of displacement and angle of rotation in the condition without noise (Spearman r?=?0.441, p?<?0.001). The rate of agreement between subjective estimation of noise influence and objective test results ranged between only 43% and 63%, depending on the question and endpoint.

Conclusion

Hearing had a clearly beneficial effect of auditory inputs on vestibulospinal coordination, especially for distance of displacement and angle of rotation.

     

Aktuelle Studienlage zur Tonsillotomie

Background

Tonsillotomy procedures (TT) are being increasingly performed owing to the low postoperative morbidity compared with extracapsular tonsillectomy (TE). Patients may experience regrowth of tonsillar tissue or tonsillitis in the tonsillar remnants eventually resulting in a secondary tonsillectomy.

Objectives

A review of the literature was undertaken to evaluate the current indications and contraindications, surgical instruments, risks of surgery, and the need for further research related to TT.

Material and methods

A search of the PubMed database was performed with the following terms: “tonsillotomy,” “partial tonsillectomy,” “subtotal tonsillectomy,” “intracapsular tonsillectomy,” “RFITT,” and “tonsil ablation.” Filters included language (English; German) and publication date (1960–2016). Articles were excluded if they were not related to tonsil surgery, did not provide clinical data, dealt with uncommon surgical techniques, or presented only data from polysomnographic studies.

Results

In all, 104 papers encompassing 97 studies and seven national surveys were eligible for analysis. In total, 13,270 patients had undergone TT and were compared with 11,485 patients after TE. Partial resection of the tonsils was most commonly accomplished with a microdebrider (51.5?%), and less frequently with coblation (20.5?%), radiofrequency (9.1?%), CO₂ laser (6.6?%), or other surgical instruments. The age in the study groups ranged between 6 months and 78 years (median: 6.0 years). The prevailing indication for surgery was upper airway obstruction resulting from tonsillar hyperplasia with (n = 20) or without (n = 60) a history of tonsillits. In seven studies, TT was explicitly performed to resolve tonsillitis, while three authors did not specify the indication for surgery. The hemorrhage rate after TT was 0.2?% on average.

Conclusion

TT is predominantly indicated for tonsillar hyperplasia, with or without tonsillitis. Restrictions related to age or surgical instruments are not reported in the literature data. Data concerning operation time, intraoperative bleeding, and outcome favor TT over TE. The median values for regrowth (3.0?%), postoperative tonsillitis (2.85?%), and secondary TE (1.37?%) emphasize the high success rate of TT. Further research utilizing a uniform terminology is mandatory to clarify the benefit of TT over TE in the long term and to resolve sleep-related breathing disorders resulting from tonsillar hyperplasia or tonsillitis.

     

Long-term vestibulocochlear functional outcome following retro-sigmoid approach to resection of vestibular schwannoma

The objective of this study was to evaluate long-term vestibulocochlear functional outcomes of patients operated for unilateral vestibular schwannoma via the retro-sigmoid approach. Patients who underwent vestibular schwannoma resection via retro-sigmoid approach between 2004 and 2008 at our institution, without prior surgical or radio-surgical therapy were considered to be eligible for this study. Preoperative auditory and vestibular symptoms were assessed retrospectively. Postoperative symptoms were prospectively assessed using a standardised questionnaire, pure tone audiometry, video-oculography, and rotary chair testing. Out of a total of 203 patients, 120 were eligible for this study, of whom 64 responded to follow-up requests and could be enrolled. Serviceable hearing was reported in 42 patients (66 %) preoperatively and was maintained in 18 (43 %) postoperatively. While no significant change in rate of tinnitus and balance impairment between pre- and postoperative periods was detected, vertigo decreased significantly (40 to 28 %, p < 0.001). Postoperative video-oculography demonstrated vestibular paresis in 80 %. Rotary chair testing demonstrated normal or central compensation in 84 %. Absence of central compensation was associated with postoperative balance disturbance (p = 0.035). Increasing tumour size and patient age, also decreasing quality of preoperative hearing were independent factors predictive of a postoperative non-serviceable hearing (p = 0.020, p = 0.039 and p = 0.002, respectively). Resection of vestibular schwannoma via the retro-sigmoid approach is associated with improvement in postoperative vertiginous symptoms. Absence of central compensation leads to increased postoperative balance disturbances. Preservation of serviceable postoperative hearing is associated with good preoperative hearing status, younger age, and smaller tumours.     

Click-Evoked Auditory Efferent Activity: Rate and Level Effects

There currently are no standardized protocols to evaluate auditory efferent function in humans. Typical tests use broadband noise to activate the efferents, but only test the contralateral efferent pathway, risk activating the middle ear muscle reflex (MEMR), and are laborious for clinical use. In an attempt to develop a clinical test of bilateral auditory efferent function, we have designed a method that uses clicks to evoke efferent activity, obtain click-evoked otoacoustic emissions (CEOAEs), and monitor MEMR. This allows for near-simultaneous estimation of cochlear and efferent function. In the present study, we manipulated click level (60, 70, and 80 dB peak-equivalent sound pressure level [peSPL]) and rate (40, 50, and 62.5 Hz) to identify an optimal rate-level combination that evokes measurable efferent modulation of CEOAEs. Our findings (n?=?58) demonstrate that almost all click levels and rates used caused significant inhibition of CEOAEs, with a significant interaction between level and rate effects. Predictably, bilateral activation produced greater inhibition compared to stimulating the efferents only in the ipsilateral or contralateral ear. In examining the click rate-level effects during bilateral activation in greater detail, we observed a 1-dB inhibition of CEOAE level for each 10-dB increase in click level, with rate held constant at 62.5 Hz. Similarly, a 10-Hz increase in rate produced a 0.74-dB reduction in CEOAE level, with click level held constant at 80 dB peSPL. The effect size (Cohen’s d) was small for either monaural condition and medium for bilateral, faster-rate, and higher-level conditions. We were also able to reliably extract CEOAEs from efferent eliciting clicks. We conclude that clicks can indeed be profitably employed to simultaneously evaluate cochlear health using CEOAEs as well as their efferent modulation. Furthermore, using bilateral clicks allows the evaluation of both the crossed and uncrossed elements of the auditory efferent nervous system, while yielding larger, more discernible, inhibition of the CEOAEs relative to either ipsilateral or contralateral condition.     

ACOUSTIC STARTLE RESPONSE AFFECTED BY AGING AND CHOLINERGIC NEUROTRANSMITTERS

The acoustic startle response has been used to evaluate tinnitus and hyperacusis in animal models. Gap induced prepulse in- hibition of the acoustic startle reflex （gap-PPI） is affected by tinnitus and loudness changes. Since tinnitus and reduced sound tolerance are commonly seen in elderly, we measured gap-PPI in Fischer 344 rats, an aging related hearing loss model, at dif- ferent agcs： 3-5 months, 9-12 months, and 15-17 months. The startle response was induced by three different intensity of sound： 105, 95 and 85 dB SPL. Gap-PPI was induced by different duration of silent gaps from 1 to 100 ms. When thc startle was induced by 105 dB SPL sound intensity, the gap-PPI induced by 50 ms silent gap was significantly lower than those in- duced by 25 or 100 ms duration, showing a ＂notch＂ in the gap-PPI function. The ＂notch＂ disappeared with the reduction of startle sound, suggesting the ＂notch＂ may be related with hyper-sensitivity to loud sound. As the intensity of the stimulus de- creased, the appearance of the hyperacusis-like effect decreased more quickly for the youngest group of rats. We also tested scopolamine, a muscarinic acetylcholine receptor antagonist, and mecamylamine, a nicotinic acetylcholine receptor antago- nist, on the effect of gap-PPI. When scopolamine was administered, the results indicated no addition effect on the hyperacu- sis-like phenomenon in the two older groups. Mecamylamine, the nicotinic antagonist also showed effects on the appearance of hyperacusis on rats in different ages. The information derived from the study will be fundamental for the further research in determining the cause and treatment for hyperacusis.