Improving regional universal newborn hearing screening programmes in Italy.

The Universal Newborn Hearing Screening (UNHS) programme aims at achieving early detection of hearing impairment. Subsequent diagnosis and intervention should follow promptly. Within the framework of the Ministry of Health project CCM 2013 "Preventing Communication Disorders: a Regional Program for early Identification, Intervention and Care of Hearing Impaired Children", the limitations and strengths of current UNHS programs in Italy have been analysed by a group of professionals working in tertiary centres involved in regional UNHS programmes, using SWOT analysis and a subsequent TOWS matrix. Coverage and lost-to-follow up rates are issues related to UNHS programmes. Recommendations to improve the effectiveness of the UNHS programme have been identified. The need for homogeneous policies, high-quality information and dissemination of knowledge for operators and families of hearing-impaired children emerged from the discussion.

Paroxysmal positional vertigo: the role of age as a prognostic factor.

Aim of this study was to examine possible relationships between several clinical aspects of paroxysmal positional vertigo and factors better defined as "intrinsic" to the patient, above all age. The disorder can affect essentially all age groups; nevertheless, the onset of age-linked degenerative processes, such as vascular damage, can have a negative influence--at least in theory--on the pathogenic mechanisms of cupulolithiasis or canalolithiasis. The study was based on the review of 566 patients with the typical form of paroxysmal positional vertigo. Based on age, the patients were divided into two groups, respectively < or =50 years and > 50 years. For the purposes of this study, a series of clinical-laboratory conditions associated with the risk of, or clear, vascular damage were also considered. The results indicate that if there are no clinical or case-history elements that can be attributed to an aetiological hypothesis, the clinical behaviour of paroxysmal positional vertigo is not affected by the age factor. However, the existence of generic vascular damage, hypothesised by the presence of the above-mentioned conditions, influences certain clinical aspects of the disorder, particularly recovery time, the trend of the active phase and the number of relapses. In conclusion, paroxysmal positional vertigo with a presumed vascular aetiology, the incidence of which increases with age, presents a worse prognosis, not only with respect to the "idiopathic" form in childhood but also the "idiopathic" type in the elderly. The lithiasic model responds well to pathogenic interpretation requirements, which envisage macular degeneration with a vascular component. However, the observation, via imaging, of diffuse ischaemic lesions in critical areas of the brainstem and the cerebellum in many "vascular" patients, does not exclude the possibility of alternative pathogenic mechanisms that, in the final analysis, can lead to compromised VOR on a central level.

Balance disorders in headache patients: evaluation by computerized static stabilometry.

OBJECTIVES: The aim of the study was to investigate the occurrence of equilibrium disturbances in headache patients, during the interictal period, by computerized static stabilometry. MATERIALS AND METHODS: Sixty-seven patients were studied: 35 with migraine without aura (MwoA), 12 with tension-type headache (TTH) in the episodic form (ETTH) + MwoA, and 20 with only TTH [10 ETTH + 10 chronic (CTTH)]. The stabilometric parameters considered were: statokinesigram length (L) and surface (S) in open (EO) and closed (EC) eyes conditions with/without occlusal bite, EC with head retroflexion (ECR), and optokinetic stimulation (OKN). RESULTS: The alteration of at least one of the stabilometric parameters was observed in 45 patients (67.2%): 21 MwoA, 8 ETTH + MwoA, and 16 TTH (8 ETTH + 8 CTTH). CONCLUSION: In TTH patients (ETTH, CTTH, ETTH + MwoA), the stabilometric findings show a proprioceptive alteration induced by cervicofacial muscle contraction, which was peripheral in origin. In MwoA patients the alterations appear under OKN and support a control impairment in involuntary oculomotility of central origin.

Identifying congenital hearing impairment. Personal experience based on selective hearing screening.

If all degrees of permanent uni- or bilateral hypoacusis are taken into consideration, hearing impairment is the most common congenital disease. Early detection of permanent infantile hearing impairment has become extremely important in preventive medicine, since steps can be taken with hearing aids and rehabilitation to ensure better development of language and higher cognitive functions. Aim of this study is to provide a critical review of the time of diagnosis of hypoacusis at our audiology laboratory, where two methods were used to screen hearing of children with/without risk indicators. Results of approximately 10 years' work were re-examined during which time outpatient screening was conducted on children referred by colleagues in neonatology and paediatrics. All were carriers of congenital risk indicators associated with sensorineural and/or conductive hearing loss, based on the Joint Committee on Infant Hearing findings, or were suspected of being hypoacusic even if they had no known congenital risk factors. Hearing screening was conducted in hospital on newborns with no risk factors, within the first few days of birth. Results of the present study showed that when selective hearing screening was performed, the mean age of high-risk patients diagnosed with hypoacusis was slightly higher than that in international guidelines. Moreover, these patients represent approximately half the hypoacusic population identified in the study period. The other half of congenital hypoacusic subjects identified had no risk indicators and there was a significant delay in diagnosis due to later manifestation of symptoms indicating hypoacusis, and thus, in turn, delayed referral for hearing tests. In contrast, subjects without risk indicators who underwent in-hospital hearing screening and proved to be hypoacusic, were diagnosed early. In our experience, however, universal screening has considerable disadvantages, such as difficulty in covering the entire population, difficulty in follow-up after discharge from hospital, and last, but by no means least, significant organisational and professional commitments, making it impossible to perform in all hospitals. In order to ensure effective hearing screening for congenital hearing loss and, thus permit prompt identification of hypoacusic children, use of hearing aids and rehabilitation screening should incorporate two aspects. First, selection should be compulsory, thereby reducing waiting time between collecting case histories and performing outpatient tests; second, hospital screening of children without risk factors should be performed whenever possible. Integrating these two aspects would make it possible to approach the "utopia" of universal hearing screening.

Treatment of severe epistaxis by superselective embolization: a review of 22 cases.

OBJECTIVES: Epistaxis represents one of the most common ENT emergencies. In this paper, the authors report their experience in treating some cases of severe epistaxis by super-selective embolization of the afferent vessels of the nasal fossae. PATIENTS AND METHODS: A retrospective study of 22 patients with severe recurrent epistaxis (1 anterior and 21 posterior). All patients had been treated unsuccessfully with repeated anteroposterior nasal packing, and presented significant secondary anaemia. Selective embolization procedures were performed under local anaesthesia. An arterial introducer is inserted into the femoral artery -generally the right one- and diagnosis as well as treatment are performed with the same guide catheter. In all cases, the terminal branches of the facial artery and of the internal maxillary artery on the side on which the haemorrhage occurred were embolized. Moreover the contralateral internal maxillary artery was always embolized as well, in order to prevent immediate recurrence of hypervascularisation of the mucosa through anastomotic paths. RESULTS: In all patients, complete devascularisation was achieved in the areas of the embolized arteries at the nasal mucous membranes, arresting the epistaxis. None of the cases experienced complications attributable to treatment. DISCUSSION AND CONCLUSION: Superselective arteriography with embolization can be considered as the method of choice in treating severe epistaxis because it can be performed under local anaesthesia and can easily be repeated if the first procedure is not successful. Moreover, it is at least as effective as ligation of the internal maxillary artery, if not more so, but it has a significantly lower complication rate which is destined to fall as the quality of the materials being used continues to improve.

Retrospective study on precancerous laryngeal lesions: long-term follow-up.

The classification and the most appropriate treatment of dysplastic lesions of the larynx continue to be controversial issues. Aim of present study was to evaluate the incidence of precancerous lesions of larynx, their potential to evolve in relation to grade of dysplasia, and the most appropriate treatment. The study is based on the review of a series of 207 patients (157 (75.9%) male, 50 (24%) female) with keratosis of the laryngeal epithelium, with or without dysplasia. Patients were divided into four groups, according to Friedmann's classification (1986), based on presence and grade of any dysplasia. The follow-up period ranged from approximately 7 to 16 years. With regard to progression of the disease, 159 of the 185 patients considered were cured following initial treatment (85.9%), whereas 26 (14.1%) had recurrences. Of the latter, 19 had a single recurrence and 7 had multiple recurrences. Progression to carcinoma occurred in a total of 12 cases, above all in patients with the highest grades of dysplasia. Results emerging from this study confirm not only that dysplastic lesions of the larynx have the potential to evolve into frankly malignant lesions, but also that this capacity to evolve is significantly correlated with grade of dysplasia of the covering epithelium. Therefore, the histological classification of precancerous lesions of the larynx, based on the presence or absence of atypical cells and on their severity, is clearly valid from a clinical standpoint, representing, above all, an important prognostic factor. As far as treatment is concerned, mucosal stripping at site of the lesion is considered to be the treatment of choice for precancerous lesions of the larynx. Nevertheless, in patients presenting keratosis with a higher grade of dysplasia, it is mandatory to consider more aggressive treatment.

"Linear" and "derived" otoacoustic emissions in newborns: a comparative study.

OBJECTIVE: To investigate the effects of a specific aspect of the acquisition procedure, the averaging technique, on the evaluation of click-evoked otoacoustic emissions (CEOAEs) in newborns. DESIGN: CEOAEs were recorded by an Otodynamic ILO88 system from 89 full-term newborns at the third day after delivery. For each ear and in the same test session, CEOAEs were evoked by 75 to 85 dB pSPL acoustic clicks and averaged according to two different modes: the "linear" (classic average) and the "derived" mode, which allows the cancellation of linear behaving components (such as acoustic artifacts). All examined ears had a normal auditory function as assessed by conventional ABR between the ages of 2 and 4 mo. CEOAEs obtained by both averaging techniques were compared on the basis of several quantitative parameters: the waveform similarity; the levels of signal and noise and the inter-test reproducibility of the broadband response and of four different frequency bands centered at 1.6, 2.4, 3.2, and 4 kHz; the amplitude as a function of time; the test time. To eliminate the contribution of the stimulus artifact, linear CEOAEs were windowed 6 to 20 msec, whereas derived emissions were windowed using the default ILO88 window (2.5 to 20 msec). Additionally, CEOAEs were classified as "pass" or "fail" accordingly to screening criteria used in the daily clinical practice. RESULTS: Linear and derived emissions had very similar wave shapes and no time shifts during the first 12.5 msec. On the contrary, clear differences in the waveforms and time shifts were observed at longer latencies. The use of both averaging techniques resulted in identical CEOAE levels for both the broadband response and for the first two tested frequencies. For the last two frequencies, emission levels were lower when averaged with the linear technique owing to the use of the time window 6 to 20 msec, which reduces the amplitudes of high-frequency components. The residual noise in derived traces is 6 dB higher than that from linear traces. Also, derived CEOAEs had a lower inter-test reproducibility in both the broadband compound emission and in the four frequency bands examined here. The greatest difference in reproducibility was observed at the lowest band (1.2 to 2 kHz). Scoring of emissions was influenced by the averaging technique: 14% CEOAEs obtained with linear averaging and scored as passes were classified as fails when averaged with the derived mode. Moreover, if a CEOAE was scored as pass when using the derived technique, it also was scored as pass when using linear averaging. The increased number of false positives most likely was due to the higher noise floor/lower signal to noise ratio (SNR) of CEOAEs obtained with the derived technique. CONCLUSIONS: In the tested newborns and at the levels of stimulation used in this study, the emissions obtained with the derived technique were noisier than those obtained with the linear technique, this being intrinsically due to the type of averaging. Therefore, screening criteria based on the evaluation of the SNR (or similar parameters) could be influenced by the type of averaging used during the acquisition.

[Postoperative follow-up of type A aortic dissectionexperience with 67 patients]. / Follow-up postoperatorio della dissezione aortica di tipo A; esperienza su 67 pazienti.

BACKGROUND: The surgical treatment of type A aortic dissection is usually palliative and most surviving patients remain at considerable risk to develop late postoperative complications; consequently, there is the need for careful long-term follow-up. The present study reports on our experience in the postoperative follow-up of a consecutive series of patients with type A aortic dissection. METHODS: Between January 1986 and December 1996, 89 patients underwent emergency surgery for type A acute aortic dissection; the overall hospital mortality rate was 22% (20/89). This study includes the 69 hospital survivors (49 men and 20 women). Forty-six patients had ascending aortic graft replacement, 13 patients underwent replacement of aortic valve and ascending aorta by a composite graft. The surgical repair was extended to the aortic arch in 5 patients. All patients were serially evaluated by clinical examination and imaging techniques (transthoracic echocardiography in all patients, magnetic resonance imaging in 40, transesophageal echocardiography in 33 and computed tomography in 25). Follow-up was complete in 97% of patients (two patients were lost to follow-up and excluded from the study) and extended to a maximum of 152 months (mean 74 +/- 39 months). The postoperative quality of life was assessed by a questionnaire in 51 current survivors. Risk factors for cardiovascular death, reoperation and poor quality of life were investigated with univariate and multivariate analysis. RESULTS: During the follow-up period 15 patients (22%) died; in 13 cases death was due to cardiovascular causes and in 6 of them it was related to aortic disease. The Kaplan-Meier survival was 92 +/- 3%, 87 +/- 5%, 78 +/- 6% and 70 +/- 8% at 2, 4, 6 and 8 years, respectively. A persistent aortic dissection was demonstrated in 50 patients (75%) and 42 of them showed the presence of flow in the false lumen. A dilatation of one or more aortic segments was found in 59 patients (88%), with a diameter > or = 50 mm in 17 and > or = 60 mm in 8. In 30 patients who underwent transesophageal echocardiography the relation between aortic dimensions and flow pattern in the false lumen was examined; the presence of aneurysmal dilatation with a diameter > or = 50 mm was significantly correlated with a "high flow" pattern. Ten patients (15%) underwent reoperation from 13 to 83 months postoperatively. Reoperation was indicated for: sinus of Valsalva aneurysm and severe aortic regurgitation (2 patients), severe aortic regurgitation (2 patients), aneurysm of the arch (1 patient), thoracoabdominal aneurysm (1 patient), periprosthetic pseudoaneurysm (4 patients). The hospital mortality rate was 20% (2 patients). Sixty-two% of current survivors are asymptomatic; 30 patients returned to their predissection status. Quality of live is judged "good" by 23 patients, "fairly good" by 21 patients and "poor" by 7 patients. No significant independent risk factor for cardiovascular death, reoperation and poor quality of life was identified. CONCLUSIONS: The long-term prognosis after surgical treatment of type A aortic dissection is not satisfactory because of a significant risk of late complications. However, the results of our study can be judged fairly good, particularly if we consider the natural history of the disease.

[Evaluation of hearing by studying acoustic distortion products in noise-induced hearing loss]. / Prévision de l'audition par les produits de distorsions chez les sourds par le bruit.

In this work, the Authors want to verify the possibility of an objective method of cochlear function evaluation in subjects affected by chronic acoustic trauma, through the study of the acoustic distortion products. Undertaking 46 subjects, the researchers have demonstrated a direct correlation between the tonal acoustic threshold and that of the distortion products. This method was able to show the useful indications of an objective evaluation of acoustic capacity in non collaborating subject. Because of the large variability of intensity of the distortion products and their absence when the acoustic threshold is more than 50-60 dB HL, they by themselves, don't permit exact evaluation of the tonal threshold for a given frequency.

[Otoacoustic distortion products in infants and adults: a comparative study]. / I prodotti di distorsione otoacustici nel neonato e nell'adulto: analisi comparativa.

Distortion Products (DP) are otoacoustic emissions evoked by emitting two pure tones. The principle advantage of this method vs. transient evoked otoacoustic emissions is the specificness of frequency. The purpose of the present work was to determine whether this technique could be applied in objective study of cochlear function in infants. This was done by setting standard data for infants and comparing them with the data obtained in a control population of adults. The input/output functions of the DP and the DP audiograms for 8 f2 frequencies ranging from 696 to 6006 Hz were studied in a group of 15 healthy, full-term infants. The data obtained were statistically compared to the data taken from a control group of 8 normal hearing adults. The infants showed significantly more intense DPs in the intermediate frequencies, with a greater detection threshold and dynamic range. On the other hand, at the high frequencies the amplitude of infant DPs was the same or lower than (f2 = 5005) those found in the adults. These differences can partially be attributed to the fact that the outer auditory channel is smaller in infants thus the probe and the middle ear are better matched. There is significantly greater background noise in infant DPs, particularly at low frequencies. This may be due to the fact that the skin of the outer auditory duct--which acts as a low-pass filter allowing suction and movement of the cervical muscles to contaminate the tracing--is thinner in infants. In conclusion, the study of DPs has shown its potential in the study of cochlear function in infants because it is non invasive and objective, it can be performed quickly and shows frequency specificness. Unfortunately, it cannot be considered a valid method for determining cochlear function at the low frequencies.

[Sudden idiopathic hearing loss. Case reports in the course of ten years]. / L'ipoacusia improvvisa idiopatica. Presentazione di una casistica decennale.

The authors present a retrospective case study of 132 subjects with sudden-onset hearing loss who had been observed during the course of 10 years. The results were compared with those available in the literature. These patients were divided into two subgroups based on age: over or under 40. The hearing loss was divided into 4 subgroups according to audiogram morphology. Then the presence, and entity, of any recovery in hearing was evaluated. There was no preference for sex while the greatest incidence was found in the VI and VII decade of life. The audiohistograms obtained when the patients were admitted to the hospital and 2 months later indicated an improvement in the hearing threshold localized above-all in the medium-low frequencies. This confirms a better evolution in those forms localized in the apex of the cochlea. The threshold of 60 dB HL is the dividing line between a totally favorable prognosis and a partially or totally unfavorable prognosis. This indirectly confirms that the intensity of the initial hearing damage is an important prognostic factor. From the morphological point of view the forms with the best evolution appear to be those with a flat or rising morphology. The forms with descending morphology do not present a favorable evolution although those with a threshold around 8000 Hz are worse than those with a threshold of 4000 Hz. As regards age no significant differences were found in the evolution of hearing loss between subjects under and over 40. In conclusion, the essential characteristics of sudden-onset hearing loss are as yet poorly defined. There are so many variables affecting the onset and evolution of hearing loss that it proves impossible to perform any statistically valid analysis which includes them all. To date the elements able to provide some degree of prognostic prediction are the audiogram morphology and the entity of the initial hearing loss.

[Results and considerations regarding auditory neonatal screening based on the use of transient evoked otoacoustic emission]. / Risultati e considerazioni a proposito di uno screening audiologico neonatale basato sull'impiego delle otoemissioni acustiche evocate transienti.

The authors present a 5-year clinical experience in audiological screening performed at the neonatal center of the Policlinico of Perugia, Italy. The study was performed using an IL088 Otodynamics unit produced by Bray & Kemp. A total of 1328 newborns (2656 ears) were tested on the 4th day of life and during spontaneous sleep. None of the children had any audiological risk factors. The test was repeated one month later for all subjects who lacked Transient Evoked Otoacoustic Emissions and in many cases ABR testing was performed by 3 months of age. The authors present the undoubted advantages of the present method which include the fact that it is a) easy to perform, b) non invasive, c) sensitive and d) effective. They then discuss the main problems which arose during the course of the screening and advance some solutions. For the most part these problems involved the high number of false positives (13.1%) and the high percentage of subjects who were lost to subsequent controls (approximately 6% of the total population). The number of false positives could be reduced by using a linear acoustic stimulation (rather than the non-linear stimulation which is the default parameter for the machine). Such a linear stimulation can improve the signal-to-noise ratio, thus making it possible to adopt a reproducibility index lower than the 70% presently used (however, this brings with it the risk of including a certain number of false negatives). Finally, they discuss the possibility of only retesting those subjects with bilateral lack of TEOAEs, thus reducing the number of check-ups to be performed a month later.

[Otoacoustic distortion products in sensorineural hearing loss in the cochlea]. / I prodotti di distorsione otoacustici nelle ipoacusie neurosensoriali di natura cocleare.

The purpose of the present work was to assess distortion-product otoacoustic emissions (DPOAE) in cochlear hearing loss and in its various morphologies. A total of 19 patients (30 ears) were selected for the study. They showed various pictures of neurosensorial hearing loss which were localized within the frequency range normally examined during audiometric tonal threshold testing. The DPOAEs were recorded using a Bray and Kemp ILO 92 instrument. The DPOAEs of several frequencies (750,1000,1500,2000,3000,4000 and 6000 Hz) were examined using an f2 tone of 696, 1001, 1587, 2002, 3147, 4004 and 6348 Hz, respectively. The results were as follows: a) At certain frequencies the overlap between hearing loss and the absence of, or reduction in, DPOAE amplitude was virtually total. b) There was a modest correlation between the degree of hearing loss and decrease in, or absence of, DPOAEs although there was a spectrum of intermediate hearing losses where the DPOAEs varied widely from one individual to another (this spectrum ranged from 10 to 45 dB HL on the audiometric tonal test). c) The absence of DPOAEs at 750 Hz is unable to predict hearing loss for this frequency as, at this frequency, there can be a lack of DPOAEs even when the 750 Hz audiometric threshold level is normal. Finally, what emerged from this study was that DPOAEs prove quite useful to complement the study of auditory brainstem responses (ABR), now universally accepted as the means for early diagnosis of hearing loss in children. In fact, ABRs provide precise data regarding a frequency field which is socially less important in terms of verbal communication and the development of spoken language. It is, however, unable to explore individual frequencies.

[Evoked otoacoustic emissions using clicks in detection of deafness in young children]. / Les oto-émissions acoustiques provoquées (OEAP) par des transitoires dans le dépistage de la surdité du jeune enfant.

Click-evoked otoacoustic emissions (EOAEs) are sounds emitted by the cochlea due to active outer hair cell contraction following stimulation of the stereocilia. The purpose of this study was to evaluate the use of testing for EOAEs as a valid auditory screening method in newborns, and 1074 healthy fullterm babies (2148 ears) with an Apgar score higher than 8 at birth were examined. EOAEs were elicited 4 days after birth and a correlation index higher than 70% represented normal response criteria. If there was no response, EOAEs and brainstem response potentials were tested at the age of one month. On the fourth day after birth. EOAEs specificity and efficiency were found to be 92.3% and 92.4% respectively, while sensitivity was 100%. Specificity and efficiency at one month were rated at 100%. The use of EOAEs offers numerous advantages over traditional auditory screening methods, thus suggesting that this technique is suitable for the mass-screening of infants.

[Products of acoustic distortion in the examination of deafness in an infant]. / Les produits de distorsion acoustique dans le dépistage de la surdité du jeune enfant.

Distortion-product otoacoustic emissions (DPOAEs) are otoacoustic emissions evoked by two pure tones. The greatest advantage of DPOAEs is their frequency specificity with respect to the eliciting bitonal stimuli. The purpose of this study was to compare DPOAEs in two populations. This paper reports input/output DPOAEs functions and DPOAE-audiograms for audiometric frequencies of f2 between 696 and 6006 Hz in a normal neonate population and in an adult control group. Fifteen healthy fullterm newborns (29 ears) and 8 normal-hearing adults (16 ears) participated as subjects. Results at medium frequencies indicate that the maximum amplitudes of the DPOAEs were generated by neonates, the detection threshold was better and the dynamic range was greater than in adults, making them potentially valid for studying cochlear functioning in infants.

[Rhinocerebral mucormycosis: a case report]. / A proposito di un caso di mucormicosi rino-cerebrale.

The Authors report a case history of rhinocerebral mucormycosis in a patient with chronic lymphatic leukaemia and recommend that therapy be based on three different approaches: treatment for the underlying disease, systematic antifungal treatment with Amphotericine B, and surgical asportation of diseased tissue. They affirm that results may be surprisingly successful, even in cases with signs of orbital-cerebral involvement which are indicative of a poor prognosis and the concomitant presence of a serous disease such as leukaemia.

Evaluation of functionality of cochlear outer hair cells in patients with retinitis pigmentosa and in their relatives.

Hearing functionality was studied in 36 patients with retinitis pigmentosa (R P) and 29 of their relatives. These patients were defined as having bilateral normal hearing on the basis of tonal-threshold audiometric and acoustic-immittance tests. The transiently evoked otoacoustic emissions (T E O A Es) were studied in these normal hearing patients. T E O A Es represent an extremely sensitive method to study the functionality of the outer hair cells of the organ of Corti. When the values of T E O A E amplitude, intensity, and frequency in R P patients and in their relatives were compared with those in control subjects, they were found to be significantly reduced. The T E O A Es were clearly pathological in 52.8% of patients with R P and in 24.1% of their relatives. During embryologic development, there is one transitory axoneme in the outer hair cells of the organ of Corti; this transitory axoneme is important for the organization of the stereocilia. Axonemes are found in mature hair cells, including photoreceptors. The alteration of cochlear outer hair cells in a high percentage of patients with R P and in some of their relatives corroborates the hypothesis that, in some instances, retinitis pigmentosa may be due to a structural anomaly of the ciliated cells.

Study of functionality of cochlear outer hair cells in patients with retinitis pigmentosa.

Hearing functionality was studied in 30 patients affected by retinitis pigmentosa (RP) and 25 of their relatives. These patients were defined as normal-hearing on the basis of pure-tone threshold audiometric and acoustic immittance tests. The evoked otoacoustic emissions (EOEs) were studied in these normal hearing patients. EOEs are an extremely sensitive method to study the functionality of the outer hair cells of the organ of Corti. In RP patients and in their relatives the values of EOE (amplitude, intensity and frequency) were found to be statistically reduced compared to those of control subjects. The EOEs turned out to be clearly pathological in 60% of patients with RP and in 24% of their relatives. During the embryologic development there is one transitory axoneme in the outer hair cells of the organ of Corti. This axoneme is important for the organization of the stereocilia. The axonemes are found inside a few mature hair cells, including the photoreceptors. The alteration of cochlear outer hair cells in a high percentage of patients with RP and in some of their relatives seems to corroborate the hypothesis that, in many cases, retinitis pigmentosa may be due to a structural anomaly of the ciliated cells.

[Otoacoustic distortion products in adults with normal hearing]. / I prodotti di distorsione otoacustici nei soggetti adulti normoacusici.

Distortion Product Otoacoustic Emissions (DPOEs) are otoacoustic emissions evoked by two pure equilevel tones (f1, f2) called primaries and are believed to provide frequency-specific information regarding cochlear function. We recorded DPOEs at 2f1-f2 frequency with a constant frequency ration (f2/f1 = 1.22) in 8 normal hearing subjects (16 ears, mean age 28 +/- 1.5) to establish the characteristics of these emissions in the adult population. DPOEs were measured at the following F2 frequencies and respective fp geometric mean frequencies: 696/632, 1001/904, 1501/1360, 2002/1809, 3003/2714, 4004/3626, 5005/4531 e 6006/5435 Hz. Detailed testing included the recording of DPOE "audiograms" and input-output functions depicting the relationship of the amplitudes of DPOE to primary-tone levels ranging from 25 to 70 dB SPL in 5 dB steps. The present findings are in good agreement with investigations based on evoked otoacoustic emissions published by other researchers. The average DPOE "audiograms" demonstrated a low-frequency maximum at 1501 Hz (f2)/1360 (fp) and a high-frequency peak at 5005 Hz (f2)/4531 (fp). The two maximum regions were separated by a minimum around 3003 Hz (f2)/2714 (fp). This study confirms the feasibility of DPOE measurements among adults and provide a normal baseline for this age group. DPOEs could be useful, in association with evoked otoacoustic emissions and with auditory brainstem responses, in obtaining a precise evaluation of the peripheral auditory system.

Evoked otoacoustic emissions behaviour in retinitis pigmentosa.

The hearing function was studied in 26 patients affected by retinitis pigmentosa (RP) and in their relatives. Sixteen patients showed bilateral normal hearing when examined with traditional audiometric methods. In these normoacusic patients evoked otoacoustic emissions (EOE) have been studied. The EOE offer a unique opportunity to measure objectively the function of outer hair cells: they record the amplitude of the energy produced by the outer hair cells of the coclea following an acoustic stimulation. The data have been statistically compared, using the Student's t-test, with those obtained in a homogeneous control-group of normal subjects. In normoacusic subjects with RP the average values of EOE intensity are statistically lower than those of normal subjects in 64 of the 127 frequency bands examined. Moreover, the distribution of the EOE in patients with retinitis pigmentosa proved to be more discontinous than that observed in the normal subjects. The EOE recorded in 14 normoacusic relatives show in some cases small anomalies but the data, on account of the limited sample group, cannot be statistically evaluated. Therefore a subclinical alteration of the Organ of Corti is found in 100% of the patients affected by RP, although they appear to be normoacusic to usual audiometric tests.