Musical training software for children with cochlear implants.

Although the voice in a free field has an excellent recruitment by a cochlear implant (CI), the situation is different for music because it is a much more complex process, where perceiving the pitch discrimination becomes important to appreciate it. The aim of this study is to determine the music perception abilities among children with Cis and to verify the benefit of a training period for specific musical frequency discrimination. Our main goals were to prepare a computer tool for pitch discrimination training and to assess musical improvements. Ten children, aged between 5 and 12 years, with optimal phoneme recognition in quiet and with no disabilities associated with deafness, were selected to join the training. Each patient received, before training period, two types of exams: a pitch discrimination test, consisting of discovering if two notes were different or not; and a music test consisting of two identification tasks (melodic and full version) of one music-item among 5 popular childhood songs. After assessment, a music training software was designed and utilised individually at home for a period of six months. The results following complete training showed significantly higher performance in the task of frequency discrimination. After a proper musical training identification, frequency discrimination performance was significantly higher (p < 0.001). The same considerations can be made in the identification of the songs presented in their melodic (p = 0.0151) and full songs version (p = 0.0071). Cases where children did not reach the most difficult level may be due to insufficient time devoted to training (ideal time estimated at 2-3 hours per week). In conclusion, this study shows that is possible to assess musical enhancement and to achieve improvements in frequency discrimination, following pitch discrimination training.

Drug-induced sleep endoscopy as a selection tool for mandibular advancement therapy by oral device in patients with mild to moderate obstructive sleep apnoea.

Nowadays oral appliance therapy is recognised as an effective therapy for many patients with primary snoring and mild to moderate obstructive sleep apnoea (OSA), as well as those with more severe OSA who cannot tolerate positive airway pressure (PAP) therapies. For this reason, it is important to focus on objective criteria to indicate which subjects may benefit from treatment with a mandibular advancement device (MAD). Various anthropometric and polysomnographic predictors have been described in the literature, whereas there are still controversies about the role of drug-induced sleep endoscopy (DISE) and advancement bimanual manoeuvre as predictor factors of treatment outcome by oral device. Herein, we report our experience in treatment of mild moderate OSA by oral appliance selected by DISE. We performed a single institution, longitudinal prospective evaluation of a consecutive group of mild moderate patients with obstructive sleep apnoea syndrome who underwent DISE. During sleep endoscopy, gentle manoeuvre of mandibular advancement less than 5 mm was performed. In 30 of 65 patients (46.2%) we obtained an unsuccessful improvement of airway patency whereas in 35 of 65 patients (53.8%) the improvement was successful and patients were considered suitable for oral device application. Because 7 of 35 patients were excluded due to conditions interfering with oral appliance therapy, we finally treated 28 patients. After 3 months of treatment, we observed a significant improvement in the Epworth medium index [(7.35 ± 2.8 versus 4.1 ± 2.2 (p < 0.05)], in mean AHI [(21.4 ± 6 events per hour versus 8.85 ± 6.9 (p < 0.05)] and in mean ODI [(18.6 ± 8 events per hour to 7 ± 5.8 (p < 0.05)]. We observed that the apnoea/hypopnoea index (AHI) improved by up to 50% from baseline in 71.4% of patients selected after DISE for MAD therapy. In the current study, mandibular advancement splint therapy was successfully prescribed on the basis not only of severity of disease, as determined by the subject's initial AHI, but also by DISE findings combined with results of gentle mandibular advancement manoeuvre allowing direct view of the effects of mandibular protrusion on breathing spaces in obstruction sites, and showing good optimisation of selection of patients for oral device treatment.

Role of inflammation in non-allergic rhinitis.

OBJECTIVE: To investigate the role of inflammation in non-allergic rhinitis (NAR) patients in a large series to establish the prevalence of different NAR-subtypes, clinical features and the role of nasal cytology in the diagnostic algorithm. METHODOLOGY: Patients were selected out of 3650 individuals who spontaneously presented at our institution. We consecutively enrolled 519 NAR-patients in an analytical cross-sectional study between November 2007 and June 2013 (level of evidence: 3b). All patients underwent rhinological evaluation including symptoms questionnaire, endoscopy, CT scan, allergy tests and nasal cytology. RESULTS: The inflammatory cell infiltrate affects the severity of symptoms differently, allowing for identification of different phenotypes of NAR. We distinguished two groups: "NAR without inflammation"(NAR-) and "NAR with inflammation"(NAR+), in addition to different NAR-subtypes with inflammation. A significant difference was observed in terms of clinical symptoms and association with comorbidities (previously diagnosed asthma and aspirin intolerance) between NAR­, NAR+ and between different NAR+ subtypes. CONCLUSION: Our data suggest that NAR- and NAR with neutrophils behave similarly, showing lower symptom score values and a lower risk of association with comorbidities compared to NAR with eosinophils and mast cells (singularly or mixed). In our belief it is very important to establish the presence and type of inflammation in non-allergic rhinitis patients and nasal cytology is a very useful test in correct differential diagnosis.

Hyoid myotomy without suspension: a surgical approach to obstructive sleep apnoea syndrome.

The aim of this study was to verify if hyoid myotomy without hyoid suspension is effective in surgical treatment of obstructive sleep apnoea syndrome (OSAS). We recruited six patients with OSAS, aged between 34 to 60 years, with retropalatal and retrolingual upper airway obstruction, non-obese (BMI < 27) and non-compliant to continuous positive airway pressure therapy. Pre-surgical clinical and instrumental evaluations included clinical examination, cephalometry, polysomnography (PSG) and sleep endoscopy. Surgical treatment included nasal surgery, uvulopalatopharyngoplasty, tonsillectomy and hyoid myotomy without hyoid suspension. Follow-up evaluations were performed with serial PSGs, performed early (one week after surgery), and at 1, 6 and 18 months after surgery. We observed that surgery was followed by immediate normalisation of breathing parameters evaluated by PSG that persisted after 18 months. Thus, hyoid myotomy without suspension combined with nasal and palatal surgery may be considered a valid treatment of non-obese OSAS patients with retrolingual and retropalatal collapse. Furthermore, we suggest that hyoid bone suspension, binding it to mandibular or to thyroid cartilage, might be unnecessary in selected cases.

The effects of cochlear implantation on quality of life in the elderly.

The purpose of this study was to evaluate the benefits of unilateral cochlear implant (CI) in patients over 60 on speech perception and quality of life, comparing the results obtained with a control group of younger CI recipients. Twenty CI users (mean age 72 years), postlingually deafened, were included in this study. Audiological performance was evaluated using bisyllabic words and sentences recognition tests in a quiet and a noise environment. Moreover, we administered two questionnaires to evaluate the health status (SF-36), CI-related effects on daily activities and personal satisfaction (Questionnaire for self-evaluation of CI benefit with SADL scale modification). Performance measures of the geriatric population showed a significant benefit on speech recognition tests compared to pre-implantation condition, even if younger CI users scored significantly better in both bisyllabic words and sentences recognition test. All study patients reported being able to have a normal conversation with an acquaintance. No significant difference was found between the study and control group in physical and mental health status, conversation with an outsider, use of TV and phone. A significant difference (p < 0.05) was noticed, instead, between elderly and younger adult patients about the overall satisfaction derived from CI. Our findings confirm the indisputable utility of CI and provide evidence that elderly patients derive a substantial benefit from it on quality of life, as demonstrated by health status, success in the common activities of daily living and perceived satisfaction after this procedure.

Role of auditory brain function assessment by SPECT in cochlear implant side selection.

Pre-surgery evaluation, indications for cochlear implantation and expectations in terms of post-operative functional results remain challenging topics in pre-lingually deaf adults. Our study has the purpose of determining the benefits of Single Photon Emission Tomography (SPECT) assessment in pre-surgical evaluation of pre-lingually deaf adults who are candidates for cochlear implantation. In 7 pre-lingually profoundly deaf patients, brain SPECT was performed at baseline conditions and in bilateral simultaneous multi-frequency acoustic stimulation. Six sagittal tomograms of both temporal cortices were used for semi-quantitative analysis in each patient. Percentage increases in cortical perfusion resulting from auditory stimulation were calculated. The results showed an inter-hemispherical asymmetry of the activation extension and intensity in the stimulated temporal areas. Consistent with the obtained brain activation data, patients were implanted preferring the side that showed higher activation after acoustic stimulus. Considering the increment in auditory perception performances, it was possible to point out a relationship between cortical brain activity shown by SPECT and hearing performances, and, even more significant, a correlation between post-operative functional performances and the activation of the most medial part of the sagittal temporal tomograms, corresponding to medium-high frequencies. In light of these findings, we believe that brain SPECT could be considered in the evaluation of deaf patients candidate for cochlear implantation, and that it plays a major role in functional assessment of the auditory cortex of pre-lingually deaf subjects, even if further studies are necessary to conclusively establish its utility. Further developments of this technique are possible by using trans-tympanic electrical stimulation of the cochlear promontory, which could give the opportunity to study completely deaf patients, whose evaluation is objectively difficult with current audiological methods.

Infant hearing loss: from diagnosis to therapy Official Report of XXI Conference of Italian Society of Pediatric Otorhinolaryngology.

Hearing loss is one of the most common disabilities and has lifelong consequences for affected children and their families. Both conductive and sensorineural hearing loss (SNHL) may be caused by a wide variety of congenital and acquired factors. Its early detection, together with appropriate intervention, is critical to speech, language and cognitive development in hearing-impaired children. In the last two decades, the application of universal neonatal hearing screening has improved identification of hearing loss early in life and facilitates early intervention. Developments in molecular medicine, genetics and neuroscience have improved the aetiological classification of hearing loss. Once deafness is established, a systematic approach to determining the cause is best undertaken within a dedicated multidisciplinary setting. This review addresses the innovative evidences on aetiology and management of deafness in children, including universal neonatal screening, advances in genetic diagnosis and the contribution of neuroimaging. Finally, therapy remains a major challenge in management of paediatric SNHL. Current approaches are represented by hearing aids and cochlear implants. However, recent advances in basic medicine which are identifying the mechanisms of cochlear damage and defective genes causing deafness, may represent the basis for novel therapeutic targets including implantable devices, auditory brainstem implants and cell therapy.

Nasal lavage CCL24 levels correlate with eosinophils trafficking and symptoms in chronic sino-nasal eosinophilic inflammation.

OBJECTIVES: The aim of our study was to measure CCL24 (eotaxin-2) levels in nasal lavage fluid of patients with different forms of sinonasal chronic eosinophilic inflammation to verify the relationship with nasal hypereosinophilia and symptoms. METHODS: Patients with nasal hypereosinophilia were randomly recruited and grouped in persistent allergic rhinitis, non-allergic rhinitis with eosinophilia syndrome (NARES) and chronic rhinosinusitis with polyps. Non rhinitic volunteers were recruited as controls. CCL24 concentration was measured by `Quantikine Human CCL24 Immunoassay`. Differential cell counts were performed by microscopic cytological examination of nasal tissue scraped by inferior turbinate. RESULTS: CCL24 levels measured in patient groups were significantly higher compared to control group with the highest levels in NARES patients. Eotaxin- 2 levels were significantly correlated to severity of symptoms and to the percentage of eosinophils in nasal tissue. CONCLUSIONS: We revealed high levels of CCL24 in all patient groups showing a significant correlation with the degree of eosinophilia and clinical symptoms. A prolonged accumulation of CCL24 inside the nasal mucosa may sustain the process of unspecific self-perpetuating eosinophil recruitment pathognomonic of these patients.

Cochlear implant patients' speech understanding in background noise: effect of mismatch between electrode assigned frequencies and perceived pitch.

OBJECTIVE: To assess the electrode pitch function in a series of adults with postlingually implanted cochlear implants and with contralateral residual hearing, in order to investigate the correlation between the degree of frequency map mismatch and the subjects' speech understanding in quiet and noisy conditions. DESIGN: Case series. SUBJECTS: Seven postlingually deafened adults with cochlear implants, all with detectable contralateral residual hearing. Subjects' electrode pitch function was assessed by means of a pitch-matching test, in which they were asked to match an acoustic pitch (pure tones delivered to the non-implanted ear by an audiometer) to a perceived 'pitch' elicited by stimulation of the cochlear implant electrodes. A mismatch score was calculated for each subject. Speech recognition was tested using lists of sentences presented in quiet conditions and at +10, 0 and 5 dB HL signal-to-noise ratio levels (i.e. noise 10 dB HL lower than signal, noise as loud as signal and noise 5 dB HL higher than signal, respectively). Correlations were assessed using a linear regression model, with significance set at p < 0.05. RESULTS: All patients presented some degree of mismatch between the acoustic frequencies assigned to their implant electrodes and the pitch elicited by stimulation of the same electrode, with high between-individual variability. A significant correlation (p < 0.005) was found between mismatch and speech recognition scores at +10 and 0 dB HL signal-to-noise ratio levels (r2 = 0.91 and 0.89, respectively). CONCLUSION: The mismatch between frequencies allocated to electrodes and the pitch perceived on stimulation of the same electrodes could partially account for our subjects' difficulties with speech understanding in noisy conditions. We suggest that these subjects could benefit from mismatch correction, through a procedure allowing individualised reallocation of frequency bands to electrodes.

Multiple viral genome search in endolabyrinthic fluids of profoundly deaf patients: possible cytomegalovirus intracochlear reactivation.

BACKGROUND: The cause of about 30% of bilateral sensorineural hearing loss (SNHL) is still unknown. A viral etiology is among the most frequently proposed ones and the supposed diagnosis is only based upon few clinical and laboratory data. The detection of viral presence within a damaged compartment may represent a way to supply interesting data for confirmation of viral etiology and to explain pathogenic mechanisms. OBJECTIVES: The aim of our study was to identify the possible presence of pathogenic viruses in the inner ear extracellular compartment in patients with bilateral severe sensorineural deafness of unknown etiology who underwent cochlear implant surgery. METHODS: 4 patients, aged from 2 to 7 years and affected by SNHL underwent cochlear implantation surgery and, at the same time, endolabyrinthine fluid sampling. The samples were subsequently sent for viral nucleic acid extraction and polymerase chain reaction (PCR) treatment: multiplex PCR and realtime-PCR were used. In each endolabyrinthine fluid sample, cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella-zoster virus (VZV), herpes simplex virus type 1 and 2 (HSV-1, HSV-2) and enterovirus genomes were searched for. RESULTS: One patient was positive for intracochlear CMV, as confirmed by another base-pair segment PCR. EBV, VZV, HSV and enterovirus were detected in none of the 4 patients. CONCLUSIONS: Our finding of CMV genome within the cochlea of a deaf patient without any evidence of acute and prenatal CMV infection suggests its possible role in postnatal inner ear injury through reactivation of latent virus within the cochlea. This hypothesis could also be considered valid for some patients with anti-CMV-IgG-positive serology and absence of endolabyrinthine viral genome since viruses can be in an inactive state at the time of fluid collection. PCR has proved to be a very useful tool in order to investigate infectious causes of deafness even for more than one virus type at a time and in a limited quantity of sample, such as the small volume of endolabyrinthine liquid collected from children during cochlear implant surgery.

Polycyclic aromatic hydrocarbons in marine organisms from the Adriatic Sea, Italy.

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in bivalves (Mitylus galloprovincialis), cephalopods (Todarodes sagittatus), crustaceans (Nephrops norvegicus) and fish (Mullus barbatus, Scomber scombrus, Micromesistius poutassou, Merluccius merluccius) in several pools coming from the Central Adriatic Sea. These marine organisms were selected because of their multitude, wide distribution and common use in the Italian diet, they were sampled and analyzed during the year 2004. Acenaphthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(ghi)perylene and indeno(1,2,3-cd)pyrene showed levels below the instrumental detection limit in all samples. Fluorene, phenanthrene, anthracene, fluoranthene, benz(a)anthracene, benzo(b)fluoranthene and benzo(k)fluoranthene were detected at different concentrations in analyzed samples. Chrysene was detected only in mussels with very low values (average 0.74ngg(-1) wet weight). PAHs composition pattern was dominated by the presence of PAHs with 3-rings (62%) followed from those with 4-rings (37%) and 5-rings (1%). Atlantic mackerel, European hake and blue whiting showed the highest PAH concentrations, ranging from 44.1 to 63.3ngg(-1) wet weight, the group of invertebrate organisms showed a level of contamination about three times lower than those of the vertebrate groups. Mediterranean mussels that did not present very high levels of contamination expressed as sum of PAHs showed one of the highest values of benzo(a)pyrene equivalents (BaPEs). Conversely the latter value was very low in Atlantic mackerel even if this species reported the highest total PAH concentrations. No significant correlation was observed between weight, length and trophic levels and total PAHs.

Auditory cortical activation in severe-to-profound hearing-impaired patients monitored by SPET.

Single photon emission tomography was used to map blood flow increase in temporal and parietal cortex after auditory stimulation in 25 subjects: 10 normal-hearing, 10 severe-profound hearing-impaired and 5 totally deaf. After a 500 Hz pure tone stimulation, a marked perfusion increase was observed, particularly at the level of the contralateral auditory temporal cortex. Blood flow increase in temporal and parietal cortical areas of normal subjects was significantly higher than that observed in severe-to-profound hearing-impaired patients. In all cases, following 500 Hz pure tone acoustic stimulation, the most lateral sagittal slice tomograms (48.75 and 56.25 mm) showed the highest blood flow increase. Statistically significant differences were also observed between normal subjects and hearing-impaired patients in the 48.75 mm sagittal tomogram. In 2 hearing-impaired patients, the single photon emission tomography pattern showed activation of the intermediate sagittal tomogram, suggesting a possible new tonotopic cortical arrangement. No significant activation was present in totally deaf patients. In conclusion, Single Photon Emission Tomography appears to be a useful tool in the evaluation of auditory cortical activation and cortical plasticity, in severe-to-profound hearing-impaired patients. Moreover, it could be a useful test for the study of auditory central pathways.

Tensor veli palatini electromyography with surface electrode applied transnasally.

A new technique is proposed for paratubal electromyography, using a surface, non-invasive, electrode applied transnasally under nasopharyngoscope guidance. This electrode records activity of the tensor veli palatini muscle during swallowing. This technique is of interest for two reasons: endoscopic guidance offers the possibility to check correct positioning of the electrode recording at tensor veli palatini muscle level. Introduction of the non-invasive surface electrode is simple and not painful.

Scanning electron microscopy of cochlea in new-born rats exposed to hyperbaric oxygen: preliminary report.

The aetiology of hearing loss in new-borns in neonatal intensive care is still debated. While the physiopathology of brain, lung and retina damage related to oxygen supplementation has been widely described, no studies have been carried out to define the relationship between hearing loss and supplementation of oxygen in new-borns. In the present investigation, the cochlear morphology of new-born rats was evaluated by means of scanning electron microscopy in order to assess morphological changes after supplemental oxygen administration. After treatment, electron microscopy revealed many changes in the morphology of outer hair cells, if compared to normal rats of the same age. The results suggest that cochlear changes are similar to those previously observed in other regions and may be related to a vascular mechanism of hypoxia-ischaemia and neovascularization and/or an oxidative stress.

Canal wall down tympanoplasty surgery with or without ossiculoplasty in cholesteatoma: hearing results.

Aim of the study was to evaluate the functional results, in two homogeneous groups, for severity of the disease, submitted to canal-wall-down tympanoplasty (TPL CWD), with and without ossiculoplasty. A total of 60 patients who underwent canal-wall-down tympanoplasty for cholesteatoma were evaluated: 31 underwent ossiculoplasty (group A) and 29 classic Wullstein type III and IV operation (group B). Hearing results were evaluated 2 years after surgery according to the AAO-HHS guidelines. Pre-operative audiometrics revealed an air conduction PTA (AC-PTA) of 45.12 dB in group A, and 56.25 dB in group B. Bone conduction PTA (BC-PTA) was 16.86 dB in group A and 26.06 in group B. Two years after surgery, AC-PTA was 42.98 dB in group A and 58.65 dB in group B; BCPTA was 18.79 dB in group A and 25.13 dB in group B. The mean pre-operative ABG was 28.44 dB in group A and 30.14 dB in group B. Two years after surgery, group A showed a mean ABG of 24.06 and group B of 35.54 dB, the difference between the two groups was significant (p = 0.03). In conclusion, the functional results observed in the present study support the need to reconstruct the ossicular chain in canal-wall-down tympanoplasty, in fact, ossiculoplasty is associated with a better hearing gain than the classic Wullstein operations.

SPET assessment of auditory cortex stimulation and tonotopic spatial distribution in auditory brainstem implant.

Activation of the auditory cortex by multifrequency acoustic stimuli has been evaluated using Single Photon Emission Tomography in a case of auditory brainstem implant after activation of 6 and 11 electrodes. Before implantation, no activation of the auditory cortex has been observed after acoustic stimulation. Following auditory brainstem implant, the stimulation of 11 electrodes showed an activation value, in terms of blood flow increase, of the contralateral temporal cortex similar to that obtained with 6 electrodes (47.70 vs. 43.76%), but a significantly stronger activation was present in the contralateral parietal region (29.59 vs. 14.73%), in the homolateral temporal area (22.02 vs. 10.46%) and, especially, in the homolateral parietal zone (16.6 vs. 4.33%). The strongest activation in the contralateral temporal cortex was detected in the sagittal tomogram at 26.25 mm from the midline, that is in the areas where high frequencies are projected, both with 6 and 11 active electrodes. The medio-lateral auditory cortex, where the middle and lower frequencies are projected, showed an overall lower activation which was however significantly lower with 6-electrode stimulation. Stimulation of the surface of cochlear nuclei determines mainly an activation of the high frequency domain, independently of the electrodes number. This finding may explain the better results of cochlear implants in comparison with auditory brainstem implant and could justify the use of needle electrodes in auditory brainstem implant. In conclusion, Single Photon Emission Tomography can be considered useful in evaluating auditory brainstem implant placement and function. It is also able to define the effectiveness of acoustic stimulation, the degree and tonotopic spatial distribution of auditory cortex activation.

Correlation between NRT measurement and behavioural levels in patients with the Nucleus 24 cochlear implant.

Aim of this study was to determine the relationship between the electrically evoked whole nerve action potential (EAP) and T- and C-level for subjects using the Nucleus 24 cochlear implant system. EAP thresholds were measured using the Neural Response Telemetry system of the Nucleus 24 device. Twelve Nucleus 24 cochlear implant users took part in this study. EAP thresholds were compared with the behavioural measures of T- and C-levels used to programme the speech processor. The EAP and the T- and C-levels were obtained, on the same day, 1 month after cochlear implant activation. EAP thresholds were seen to fall between the T- and C-level. On average, EAP thresholds fell at 72% of the map dynamic range. The majority of absent answers were found in three of the 12 patients, and out of a total of 195 activated electrodes an EAP was recorded in 169. These data show that Neural Response Telemetry is a valuable clinical tool in the Nucleus cochlear implant system, providing information concerning integrity of the implant and status of the peripheral auditory nerves.

Postural control and glycerol test in Ménière's disease.

Ménière's disease is a clinical disorder, characterized by fluctuating hearing loss, recurrent spontaneous episodic vertigo, tinnitus and aural fullness, which may be defined as the idiopathic syndrome of endolymphatic hydrops. The most important test for diagnosis of Ménière's disease is the glycerol test. This is a simple and rapid method and several authors have confirmed its efficiency for identifying endolymphatic hydrops. This test provides information on the cochlear response to the osmotic changes produced by glycerol in the inner ear, whereas modifications in the vestibular labyrinth are usually not evaluated. The aim of this study was to evaluate the effects of glycerol on postural control during attacks of Ménière's disease, and to correlate this data with data on cochlear function. After the glycerol test, an improvement in postural control was recorded in 70% of patients, with all patients reporting a recovery of vertigo. The impairment of postural control during endolymphatic hydrops could be related to a pressure increase in the labyrinth, which interferes with the normal dynamics of the endolymph, and a rapid functional recovery could occur during an osmotic depletion. Dynamic posturography improves the sensitivity of the glycerol test and may therefore be useful in the diagnosis and staging of Ménière's disease.

The role of cholinergic transmission in outer hair cell functioning evaluated by distortion product otoacoustic emissions in myasthenic patients.

Outer hair cells (OHCs) are the source of otoacoustic emissions, following a tropomyosin-miosin-dependent contraction, which are regulated by the olivocochlear bundle via the release of acetylcholine (ACh). ACh acts on ACh receptors (AChR) located on the OHC post-synaptic membrane. In myasthenia gravis (M.G.) neuromuscular transmission is reduced due to the action of AChR autoantibodies. It has previously been shown that M.G. induces a reduction in transient evoked otoacoustic emissions (TEOAEs), which is reversed after administration of a cholinesterase (AChE) inhibitor. Distortion product otoacoustic emissions (DPOAEs) were recorded before and 60 min after oral administration of 60 mg pyridostigmine bromide in 25 patients with normal hearing affected by M.G. The results were compared with those from 25 age-matched normal controls. Mean values of DPOAE amplitude in myasthenic patients were significantly (p < 0.05) lower at all frequencies before drug administration. All patients showed an overall significant (p < 0.05) increase in DPOAE amplitude after drug administration, although without reaching the control values. Such a recovery was more evident and highly significant (p < 0.01) for middle and high frequencies and could be explained by a higher concentration of ACh receptors in the basal and middle cochlear turns. These data seem to confirm the role of ACh in the neurotransmission of the auditory efferent system and may represent a new in vivo model for the investigation of the physiology of this system.