Distortion product otoacoustic emmissions in Ménière's disease.

Distortion product otoacoustic emissions (DPOAEs) are an objective, non-invasive measure for evaluating outer hair cell (OHC) activity. In this study DPOAEs were measured in 70 patients affected by Meniere's disease (MD). In addition 58 out of 70 patients performed both an audiometric threshold evaluation pre- and postglycerol administration (i.e. glycerol test) and DPOAEs pre- and post-osmotic drug assumption. The purpose of this combined form of testing was to explore the effects of glycerol on the active non-linear mechanisms of the cochlea. More than 60% of the ears with MD emitted DPOAEs despite the presence of an average hearing threshold level above 40 dB (HTL). Changes in the DPOAE baseline measures were observed in 32.4% of cases after glycerol administration. Patients were divided in four groups according to the different pattern of DPOAEs shown after the glycerol test. In particular, three-quarters of cases showed a significant increase in DPOAE amplitude, one-quarter of patients, who initially did not express DPOAEs, eventually did after intake of the osmotic agent, while no decreased DPOAEs were observed in these series. The different expressions of DPOAEs should be associated with the evolutive phases of MD. In addiction, elucidation of the relationship between DPOAEs and the stages of MD was an outcome of this test.

[Analysis of otoacoustic distortion products in a group of otosclerotic patients]. / Analisi dei prodotti di distorsione otoacustici in un gruppo di pazienti affetti da otosclerosi.

There is indication that middle ear pathologies can affect otoacoustic emissions (OAE) to varying degrees. In fact, since acoustic emissions are recorded in the outer ear duct, the energy transfer mechanisms both up and downstream of the middle ear must be intact. OAE distortion products (DP) enable one to analyze cochlear response by frequency and to verify the retrograde response as a function of frequency. In the present work this method was used to test otosclerosis patients. A group of 45 patients with otosclerosis was tested to determine whether the OAE-DP could be identified and measured. Subsequently the characteristics of these DPs were analyzed in a group of 18 subjects who had previously undergone stapedectomy. All the results obtained were compared with those from a control group of normal hearing subjects with normal emissions and free of any E.N.T. pathology. In approximately half of the cases (53%) in the otosclerosis patient group it was possible to detect clearly evident DPs. Obviously, the DP-Gram differed greatly and average amplitude was lower than those found in normal subjects. Indeed, there was no signal at all at the lower and middle frequencies reflecting a hearing loss typical of cases of otosclerosis. Most (58%) of the otosclerosis patients who had successfully undergone stapedectomy recorded valid DPs. The DP-Gram frequency range was much broader (750-4000 Hz) than in those who had not undergone surgery. Moreover the lower and mid frequency amplitudes were significantly better. The data obtained are quite encouraging and suggest that DP should be studied in depth in patients with otosclerosis.

[Initial symptoms in Meniere's disease]. / I sintomi precoci della malattia di Menire.

Menière's disease appears with the classic triad of symptoms in about 1/3 of cases so that, on the whole, diagnosis is delayed until full symptomatology develops. Spontaneous reversibility and effective control, if any, of the disease mechanism are limited to the beginning phases and thus it seems appropriate focus attention on the earliest symptoms. Unfortunately, the pre-diagnosis period is poorly known and, for this reason, we decided to investigate it in our series. The purposes of this research were: 1) to estimate the prevalence of isolated symptoms in subjects successively found to be menieric; 2) to make a clinical outline of the pre-diagnosis period; 3) to investigate the relationship between the pre-diagnosis period and the post-diagnosis disease course. From a group of 216 Menière's patients (diagnosed according to the 1985 AAOO criteria), 170 were selected on the basis of availability of audiometric and clinical data pertaining to the pre- and post-diagnosis disease course. Isolated symptoms in the pre-diagnosis period were found in 107/170 subjects (63%). The nature of the symptoms was cochlear (71.9%), vestibular (22.4%) and mixed (5.6%). In the largest group of patients (41 cases), the pre-diagnosis period lasted from 2 to 5 years. This period was shorter in the cases with mixed symptoms in comparison with patients suffering from either cochlear or vestibular symptoms. Between the 2nd and 5th year following diagnosis, hearing was seen to deteriorate more significantly in patients with a history of isolated cochlear symptoms. Furthermore, patients whose first disturbances were of cochlear origin suffer significantly shorter vertigo attacks.(ABSTRACT TRUNCATED AT 250 WORDS)

[Distortion products in Menière's disease]. / I prodotti di distorsione nella malattia di Menière.

Distortion Product Otoacoustic Emissions (DPOAEs) are elicited by simultaneous application of two tones to the ear canal. These emissions are a result of nonlinear mechanical characteristics of the cochlea at a specific point and have a precise mathematical relation with the frequencies of the two eliciting primary tones f1 and f2. This frequency-selective property of DPOAEs suggests that they should be regarded as useful monitor of localized cochlear function at any predetermined frequency. The present study was designed to investigate DPOAEs in patients with Menière's disease. DPOAEs were recorded before and after glycerol administration to verify if the fluctuation of the hearing threshold induced by this hyperosmotic agent causes selective changes in the activity of the outer hair cells. DPOAEs were present in patients in which the mean duration of the disease was shorter compared to those patients without measurable DPOAEs. An improvement of DPOAEs after glycerol intatte was observed in a half of our cases. The improvement of DPOAEs does not appear to be brought about by modifications of the auditory threshold induced by glycerol.

[Recovery from Meniere's disease]. / La guarigione della malattia di Ménière.

When vertigo attacks and balance disorders stop, menieric patients are generally considered recovered although they complain of more or less severe sensorineural hearing loss. As far as a true clinical recovery is concerned, the Authors think that it should correspond not only to absence of vertiginous spells but even to a long lasting normal and stable hearing level. On the basics of this presumption, they select the files of 7/207 patients showing complete recovery since not less than 8 years. Age at the onset of the disease, associated disease, isolated symptoms before the appearance of the classic triade, age at the first attack, total number of crises, length of active period of the disease, maximum hearing loss, shape of audiometric tracing are all analyzed. Healed patients are characterized by a smooth evolution, which reverses in the very first phases of the disease, as well as by the following: 1) absence of head injury and viral labyrinthitis in clinical history; 2) onset of disease with complete symptomatology; 3) slight hearing loss and up-sloping audiometric configuration; 4) few attacks of vertigo (less than 30) lasting no longer than 12 hours; 5) active period of disease not exceeding 18 months. Recovery from Ménière's disease seems possible as long as labyrinth lesions are not stabilized.

[Effect of acetazolamide on Menière's disease]. / Effetto dell'acetazolamide sulla malattia di Menière.

The effect of acetazolamide was assessed in 25 patients with Menière's disease. During the test session hearing threshold and plasmatic osmolality were monitored along with fluctuations in hearing loss, fullness, tinnitus and balance. A single, 250 mg dose of acetazolamide was administered to all patients via os early in the morning on an empty stomach. Hearing was tested prior to administration and every hour for five hours thereafter. Plasmatic osmolality was also assessed during the same session. In 52% of this group an improvement in the threshold was seen. The greatest shift was observed two hours after administration of acetazolamide at 250 Hz, whereas the smallest threshold shift corresponded to 2000 Hz. In all cases, plasmatic osmolality remained constant throughout. Of the patients 44% presented an improvement of all or one of the symptoms: hearing loss, tinnitus, fullness, balance. The data were compared with data obtained for a control group (9 patients) which received a placebo while following the same testing criteria. The results of this study suggest that acetazolamide can have a positive effect on endolymphatic hydrops. It should be stressed, therefore, that acetazolamide could be introduced in the diagnostic and therapeutic strategies applied in Menière's disease.

[Bell's palsy. Longitudinal study of 120 cases]. / Paralisi di Bell. Studio longitudinale su 120 casi.

The Authors have studied 120 cases of Bell's palsy, who underwent regular controls along 360 days from the beginning of the disease. The study has been carried out by means of two different parameters of evaluation, a clinical and electrophysiological one, which allowed us to obtain very interesting results, especially as regards the prognostic aspect.