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Biomedical subjects

A Quaranta

Publications and source records attributed to A Quaranta.

At least 19 recordsLinked to original sources
PubMed1992

Candida and stapedial otosclerosis: histopathological findings.

The stapes of 6 patients with stapedial otosclerosis was found to contain fungus hyphae (Candida) in the sectioned specimens. The footplate of all cases and the head of the stapes in 2 of the cases revealed single or multiple erosion cavities containing numerous thin branching PAS-positive fungus hyphae with swollen terminal endings and scanty blastospores. Osteoclasts were not observed; occasional osteoblasts, blue mantles and otosclerotic foci were seen. Four patients had been treated for several years with antibiotics and corticosteroids for recurrent serous otitis media and 1 patient had had frequent catheterization of the eustachian tube. It may be suggested that the Candida infection was a secondary event induced by a general and/or local immunodepressed condition.

Adolescent↗
PubMed1992

Psychoacoustical performance in children.

In order to contribute to knowledge of the elementary auditory functions in infancy, a group of normally hearing children below the age of four years was examined using advanced tests for cochlear (remote masking, brief-tone audiometry, critical ratio) and central auditory functions (masking-level difference). The results showed that both cochlear and central auditory functions were almost the same in three-year-olds as they were in adults, if not better. This behavior is similar to that recorded with electrophysiological methods and leads to the conclusion that at age three years the auditory system has completed its neurofunctional maturation and it is therefore completely efficient in its elementary psychosensorial functions.

Acoustic Stimulation↗
PubMed1992

[Psychoacoustic tests: effects of atropine].

The efferent pathways exert a control action on the function of the cochlear nucleus and hair cells. Acetylcholine is the neurotransmitter of the centrifugal system and its action can be blocked by atropine. In order to give a contribution to the knowledge of the function of the efferent bundle and of the cochlea efficiency we examined 10 young normal subjects before and after infusion of 1 mg of atropine i.v. a battery of three psychoacoustical tests (Remote Masking, Critical Ratio and Brief Tone Audiometry). After infusion of atropine we have shown an increase of 0.25 Hz hearing threshold, an increase of RC values and a decrease of RM values. It can be concluded that the pharmacological block of the olivo-cochlear bundle determines a stiffness of outer hair cells and basilar membrane; this finding means that the atropine can inhibit the facilitating activity of the efferent system on the cochlear performance.

Adolescent↗
PubMed1992

[Critical ratio: effects of contralateral masking on normal and pathological ears].

In order to evaluate the central interferences on the auditory efficiency, the effect of contralateral masking noise on Critical Ratio (CR) has been studied in 14 normal ears (control group), in 12 ears with cochlear disorders and in 6 with retrocochlear lesion (acoustic neuromas); in all cases the impairment was unilateral, while the other ear was normal. CR values were calculated for 1 KHz pulsed tones (duration 500 ms, rise/fall 25 ms, duty cycle of 50%); the masking noise was a wide band (90-20,000 Hz) delivered at 40 dB SL. The results have demonstrated that in the presence of contralateral masking noise, CRs don't modify both in the normal ears and in those with retrocochlear disorder, whereas they increase, almost always, in ears with cochlear deafness. These results demonstrate that the involvement of central auditory pathways, because of contralateral noise, makes the auditory efficiency worse, only in ears with cochlear dysfunctions; this behaviour seems to confirm the peripheral origin of CR.

Adolescent↗
PubMed1992

[Brain-stem auditory pathways: effects of atropine].

The efferent pathways exert a control action on the function of the cochlear nucleus and hair cells. Acetylcholine is the neurotransmitter of the centrifugal system and its action can be blocked by Atropine. In order to give a contribution to the knowledge of the function of the efferent bundle, Auditory Brainstem Responses (ABRs) and Acoustic Reflex Latencies (ARLs) have been examined in 10 young normal subjects there was also a decrease in latency greater than or equal to 100 microseconds by at least other two waves. The only statistically significant difference was relative to the latency mean value of the wave III recorded in contralateral derivation at 11 pps. The ARLs, after the infusion of atropine, showed a statistically significant increase in 7 of the 10 cases; no change was recorded in the AR amplitude. It can be concluded that the pharmacological block of the olivo-cochlear bundle determines a delay in the neural conduction of the acoustic impulses; this finding means that the atropine can inhibit the facilitating activity of the efferent system on the brainstem afferent pathways.

Acetylcholine↗
PubMed1992

[Evoked acoustic oto-emissions in cochlear deafness].

In order to give a contribution to the genesis of the EOAEs, we have recorded echos in 24 subjects with unilateral sudden deafness (I. group); 20 ears with Menière disease (II. group); 22 ears with progressive sensorineural hearing loss (III. group) and 10 normally hearing young subjects as control group. The results have shown that the EOAEs were present in 100% (I. group), 84.6% (II. group) and 86.3% (III. group) in response to the tone-burst; while the echos were present only in the 57.1% (I. group), 38.4% (II. group) and 45.4% (III. group) in response to the click, although the audiometric threshold mean were greater than 45 dB HL for 2-4 KHz and 1 KHz in the three experimental groups except for 2-4 KHz in the subjects with Menière disease (37.5 dB HL). The properties of EOAEs (detection and saturation threshold, dynamic range and duration) depended on the degree of hearing loss. Our results seem to corroborate the hypothesis that EOAEs could be also produced by a passive intracochlear mechanism attributable to the travelling wave of the basilar membrane provoked by the perilymph. In the normal ear this passive mechanism could be superimposed by an active mechanism, linked to the contractile activity of the outer hair cells with a consequent increase in amplitude of the EOAEs for the same stimulus intensity.

Acoustic Stimulation↗
PubMed1992

[Evoked oto-acoustic emissions in retrocochlear deafness].

In order to give a contribution to the genesis of the EOAEs, we have recorded the echoes in 6 subjects affected with unilateral acoustic neuroma, surgically proven (I. group); 11 subjects with sensorineural hearing loss with electrophysiological or balance signs of retrocochlear impairment (II. group) and 10 normally hearing young subjects as control group. In this study EOAEs have been recorded in response respectively to 3 ms 1000 Hz tone-burst and to 200-5000 filtered click, both sending with 2048 stimuli, at a repetition rate of 21 pps and different stimulus intensities ranging from 40 db SPL to saturation threshold in 10 db steps. The results have shown that the EOAEs were present in half of the tested patients in response to the clicks in both I. and II. group and in all the ears to the tone-burst although the 1.0 KHz audiometric threshold mean were > 65 db HL in I. group and in a third of the subjects in the II. group. The properties of EOAEs (detection and saturation threshold, dynamic range and duration) depended on the degree of hearing loss. These results suggest that acoustic tumor could determine a wallerian degeneration of the external fibers of the VIII nerve and consequently a dysfunction of the correspondent external hair cells of the cochlea, while in the II. group a contemporary or secondary involvement of the cochlear structures is possible.

Adult↗
PubMed1990

Subclinical changes of auditory function in the aged.

Elderly normal hearing subjects were studied using tests for cochlear functions (remote masking, brief tone audiometry, critical ratio, evoked otoacoustic emission), for neural auditory function (tone decay) and for central auditory functions (ipsilateral vs. contralateral acoustic reflex, tonal masking level difference). The findings demonstrated that ageing can cause subclinical abnormalities, almost consistently localized to the inner ear vibrating structures and only occasionally to the sensory and/or neural elements.

Acoustic Impedance Tests↗
PubMed1988

Cholesteatoma surgery: open vs closed tympanoplasty.

The purpose of this report is to compare closed tympanoplasty (canal wall up) and open tympanoplasty (canal wall down) performed in ears with extensive cholesteatoma operated on and followed up during the past 11 years. The study has demonstrated that there are no significant differences between open and closed tympanoplasties in terms of both postoperative subjective problems and auditory results. The only definite difference relates to recurring cholesteatoma: canal wall-up operations are complicated by recurrence of cholesteatoma in a not insignificant number of ears and require a planned two-stage procedure in all the cases. By contrast, the postoperative clinical course of open tympanoplasties has been only rarely affected by cholesteatomatous complications. It is concluded that reduction of cholesteatoma recurrence to the greatest degree possible necessitates removal of the canal wall. Open tympanoplasty is an effective alternative for closed tympanoplasty in all cases in which there is a contraindication to preserving the canal wall and in all patients whose medical or social conditions prevent scheduling an operation in more stages.

Adolescent↗
PubMed1986

Otomastoid cholesteatoma in children: histopathological findings.

Clinical experience has shown that the otomastoid cholesteatoma is more aggressive and has a less favourable prognosis in the child than in the adult. In an attempt to verify whether, in children, the clinical behaviour of the cholesteatoma depends on the histomorphological characteristics of the perimatrix, we carried out a study of samples taken from 30 subjects under 16 years of age and from 30 adults (control group) during surgery for otomastoid cholesteatoma. The study took into account the number of plasmacytes, lymphocytes, macrophages, granulocytes and giant cells per high potency field (X 630). The results showed that in young subjects the perimatrix of the cholesteatoma is richer in mononuclear inflammatory elements with evidence of enzyme-collagenase activity. On the basis of this behaviour the authors conclude that the histomorphological characteristics of the surrounding matrix can play an important role in the pathogenesis of cholesteatoma and may explain the clinical differences that can be seen between cholesteatoma in children and in adults.

Adolescent↗
PubMed1986

ABR in multiple sclerosis. Ipsi- versus contralateral derivation.

Brainstem auditory evoked potentials (ABR) were recorded simultaneously between vertex and ear lobe, ipsi- and contralateral to the stimulated ear in 53 subjects with confirmed (19) or undefined (34) multiple sclerosis. Results were compared with those obtained in a control group of 20 normal-hearing adults. The control group showed that significant latency differences exist between ipsilateral and contralateral recordings. Definition of abnormality was based on absence and separation of waves. The results showed that the use of contralateral derivation in ABR recordings increased detectability from 74% to 89% in patients with confirmed MS and from 9% to 21% in cases of undefined MS. It is proposed that parameters of contralateral ABRs be included among the criteria used for the otoneurological diagnosis of patients with CNS lesions.

Adolescent↗
PubMed1986

Remote masking, brief tone audiometry and critical ratio in sensorineural hearing losses.

Aim of this study is to evaluate in ears with different kinds of perceptive disorders the relationships between Critical Ratio (CR), Remote Masking (RM) and Brief Tone Audiometry (BTA) in order to analyse to what extent cochlear efficiency depends on functional properties of the mechanical extrasensorial structures and/or of the sensorial elements in the inner ear. Present results show that in ears with non retrocochlear sensorineural losses CR results are more often affected than RM and BTA. A reduced cochlear efficiency is related more to a failure of the mechanical properties than to dysfunctions of the cellular elements within the inner ear; presumably, micromechanisms not yet understood or unknown interfere with the efficiency of the cochlea.

Adolescent↗
PubMed1978

Remote masking in presbycusis.

Remote Masking (RM) (a rise in threshold for low-frequency tones when the ear is exposed to a high intensity noise band of high frequency) has been attributed to mechanical nonlinear distortion of the cochlear partition, as an effect of the envelope of a nonuniform signal. Clinical studies using RM have revealed RM is normal only when both the endolabyrinthine pressure and the cochlear hydrodynamics are normal. Increasing the stiffness of the cochlear partition affects adversely the mechanism of motion of the cochlear duct and reduces RM values. We studied RM in normal young Ss and in patients with presbycusis in order to determine whether aging of the inner ear also induces stiffness of the cochlear partition. In presbycusic Ss the RM values were indeed reduced symmetrically in both ears and progressively as a result of aging. Thus RM demonstrates the existence of cochlear conductive presbycusis and can be considered a useful test of stiffness of the cochlear partition.

Adolescent↗