Biomedical subjects

V Sallustio

Publications and source records attributed to V Sallustio.

7 recordsLinked to original sources

PubMed1998

Development of resistance to noise.

Recent investigations have demonstrated that in animal models repeated exposures to mid-intensity noise induce a progressive reduction of the temporary threshold shift (TTS) following the exposures. This phenomenon is named "conditioning" and it is actually able to reduce the permanent threshold shift (PTS) following exposure to high intensity noise; this finding is named "toughening". In the present work the fundamental steps of the research concerning the toughening are reviewed and the biological mechanisms supposed to be underlying this phenomenon discussed. The few preliminary results of the studies on humans are also reported.

Animals↗

PubMed1998

Auditory dysfunction in occupational noise exposed workers.

Occupational noise-induced hearing loss (NIHL) is well known to be an epidemiologically relevant problem. The subjects affected with NIHL show alteration of hearing thresholds as well as a worsening of the cochlear analysis functions and, usually, an impaired speech discrimination in presence of background noise. The study has evaluated the relationships between hearing threshold and equivalent exposure lever per day (Lepd), age and working seniority in a homogeneous sample of occupationally noise exposed workers. Three subgroups were also selected to study the most important cochlear functions as well as nerve and central functions. The first subgroup (Nn) contained normal hearing workers exposed to non-hazardous noise, while the second (Bn) contained workers exposed to high level continuous noise during their work day without clinical evidence of NIHL. The third subgroup (Bd) included subjects affected with the typical 4 kHz notch exposed to the same noise conditions than subgroup Bn. The results show that the hearing impaired subjects have the worst overall cochlear performance; however also the normal hearing workers exposed to hazardous noise have worse performance than subgroup Nn, relatively to high frequency thresholds, frequency resolution, TEOAEs, DPOAEs, stapedial acoustic reflex dynamic parameters. The results suggest that these measures could be used in the monitoring of the NIHL as indicators of subtle alterations of the hearing function.

Acoustic Impedance Tests↗

PubMed1997

Remote masking in noise-exposed chinchillas.

Remote masking (RM), the phenomenon whereby an intense high-frequency masker elevates thresholds for low-frequency signals, has been shown to be sensitive to various types of hearing loss in humans and to temporary threshold shifts in chinchillas. In this experiment, RM was evaluated in chinchillas with permanent threshold shift (PTS). Thresholds for 0.5 and 1 kHz tones were measured in quiet and in the presence of an 88 dB SPL narrow band noise centered at 3 kHz in the animals exposed for 30 h to impact noise at 125 dB SPL as intensity. The results show that RM values are significantly lower in chinchillas with PTS than in normal hearing chinchillas.

Animals↗

PubMed1997

Comparison of long-term hearing results after vestibular neurectomy, endolymphatic mastoid shunt, and medical therapy.

OBJECTIVE: This study aimed to compare the hearing changes in the long term after vestibular neurectomy, endolymphatic mastoid shunt, and medical treatment in classic Meniere's disease. STUDY DESIGN: A retrospective case review was conducted based on audiologic follow-up between 5 and 21 years. SETTING: The study was performed at two centers in Bari University Hospital, one performing vestibular neurectomy as the first surgical procedure for Meinere's disease and the other, endolymphatic mastoid shunt. PATIENTS AND INTERVENTIONS: Of 68 patients with intractable idiopathic Meniere's disease, 29 underwent middle fossa vestibular neurectomy, and 17 had endolymphatic mastoid shunt; 22 were offered surgery but declined. MAIN OUTCOME MEASURES: Outcome measures were puretone average (PTA), speech reception threshold, and speech discrimination score before and after treatment. RESULTS: PTA declined by an average of 9.3 dB in neurectomy patients, 13.3 dB in patients undergoing endolymphatic mastoid shunt, and 18.1 dB in patients who were offered surgery but declined. Patients were subdivided into two cohorts based on their preoperative or initial PTA. In the patients who had PTA scores worse than 50 dB initially, the PTA declined an average of 4.3 dB in the vestibular neurectomy group, 11.5 dB in the endolymphatic sac group, and 4 dB in the nonsurgical group. In the patients with PTA > or = 50 dB initially, the PTA declined an average of of 25.3 dB in the vestibular neurectomy group, 16.1 in the endolymphatic sac group, and 26.2 dB in the nonsurgical group. Although shunt patients with good hearing initially deteriorated less than neurectomy patients and less than patients who declined surgery, the difference was not significant. CONCLUSIONS: These results indicate that patients with poor hearing stabilized, while patients with good hearing continued to deteriorate. The same conditions were observed in the patients who had surgery and those who were offered surgery but declined.

Adult↗

PubMed1996

Epidemiology of hearing problems among adults in Italy.

Estimates for the prevalence of self-reported hearing disability and measured hearing impairment as a function of age in the adult population of Italy are reported. The study was conducted in Bari, Florence, Milan, Padua, Palermo with questionnaire and audiological assessment; neither stage showed any gross bias arising from the particular cities chosen. The results have demonstrated that: 22% of subjects think their hearing abnormal, 24.4% report some difficulty understanding speech, 14.5% experienced prolonged spontaneous tinnitus and 17% have a > or = 25 dB HL bilateral hearing impairment; hearing problems increase progressively with age and show no significant differences between men and women; the occupational groups most at risk as far as hearing impairments are concerned are manual workers and workers exposed to occupational noise; the systemic disorders most significantly connected to hearing problems are dyslipidosis, diabetes, hypertension, cardiovascular diseases, liver diseases and cervical arthrosis; among every day habits, the consumption of alcohol seems the only element of risk, above all for tinnitus.

Adolescent↗

PubMed1994

The effect of 'conditioning' exposures on hearing loss from impulse noise.

Research has shown that prior noise exposures or 'conditioning' can moderate the amount of permanent threshold shift (PTS) from subsequent high intensity noise exposures. The aim of this experiment was to study the effect of 'conditioning' on subsequent exposure to high intensity impulse noise. The subjects were seven experimental and 14 control monaural chinchillas. Evoked potential (EVP) thresholds were measured before and after the noise exposures. Experimental animals received 10 days of exposure to an octave band noise (OBN) centered at 0.5 kHz OBN at 95 dB SPL (6 h on/18 h off) and allowed to recover for 5 days. The subjects were then exposed to an impulse noise at 150 dB SPL. The temporal spacing of the impulses consisted of a series of 50 pairs of impulses presented 50 ms apart with 1000 ms between the onset of each pair. The total duration of exposure was approximately 1 min. Control animals received only the impulse noise exposure. PTS was measured after 4 weeks. The threshold shift (TS) patterns during the 'conditioning' phase were consistent with previous research, with the greatest amount of TS occurring on the second day and decreasing with continued exposures. Four weeks after recovery from the impulse noise, the experimental animals showed significantly less PTS than the control animals. In addition, histological examination revealed significantly less hair cell loss in the experimental than in the control subjects. The results are discussed in the context of previous studies on 'toughening' and on the effects of impulse noise.

Acoustic Stimulation↗

PubMedDate not supplied

Long-term outcome of Ménière's disease: endolymphatic mastoid shunt versus natural history.

This retrospective study evaluates the outcome of 38 patients with intractable Ménière's disease with a minimum of 7 years follow-up. Twenty underwent endolymphatic-mastoid shunt (EMS) and 18 were offered surgery but declined (natural history, NH, group). At the last control, 85% of the patients who were operated on (EMS group) and 74% of the NH patients had complete or substantial control of vertigo. The difference between the two groups was not significant. However, it was significant at 2 and 4 years follow-up. At 2 years, EMS patients had complete or substantial control of vertigo in 65% of the cases, at 4 and 6 years in 85% of the cases. Only 32 % of the NH patients had complete or substantial control of vertigo at 2 years. This percentage rose to 50% at 4 years and to 74% at 6 years. Hearing results in the two groups were not significantly different. Tinnitus disappeared or decreased in 56% of the EMS patients and in 18% of the NH patients. Sixty-seven percent of the EMS patients and 29% of the NH patients reported that their aural fullness was abolished. In conclusion, over the years, approximately 8 out of 10 of our patients with Ménière's disease achieved complete or substantial control of vertigo; however, this reduction was observed earlier in EMS patients than in those who declined surgery.

Adult↗