Biomedical subjects

V Colletti

Publications and source records attributed to V Colletti.

67 records · Page 4Linked to original sources

PubMedDate not supplied

Myocardial activity during noise exposure.

The present investigation was performed to study coronary blood flow along with other indices of cardiac activity in subjects exposed to short-term noise. The study was carried out on 10 normal-hearing individuals suffering from Variant Angina of Prinzmetal. The acoustic stimuli consisted of 100 dB (A) broad-band noise, lasting 30 s. The following parameters were examined: ECG (D1, D2 and D3) and heart-rate by means of electrocardiographic recording, left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP) and dP/dT max by means of arterial catheterization, and coronary blood flow by means of the thermodilution method. The results, statistically evaluated by means of multiple comparison test and t-test, did not reveal any significant modifications in the ECG traces, LVEDP, or dP/dT max. The transitory and moderate variations of LVSP and heart rate were not reflected in coronary blood flow, which remained unchanged during and after noise exposure.

Adult↗

PubMedDate not supplied

Chemical labyrinthectomy with NaCl. Menière's disease treatment with deposition of NaCl in the vestibule.

Thirteen individuals with unilateral Menière's disease were chosen for experimental chemical labyrinthectomy. All subjects suffered from frequent attacks of disabling vertigo and had mean pure-tone thresholds greater than 50 dB in the affected ear. The surgical procedure was similar to stapedectomy; after removal of the stapes, several crystals of NaCl were placed in the vestibule which was then covered with a vein graft. Postoperative recovery was rapid, allowing patients to be discharged 4-6 days after surgery. Of the 13 subjects, all reported complete relief from vertigo. Tinnitus was cured in 7 subjects, greatly improved in 4 and unchanged in 2. Most patients complaining of aural fullness preoperatively reported relief from this symptom following surgery. To date (up to 4 years post-surgery) none of the subjects has shown any significant alteration in audiologic or vestibular function in the contralateral ear. The ease and safety of this procedure make it an attractive method when cochleovestibular deafferentation is indicated.

Adult↗

PubMedDate not supplied

Stapedius reflex abnormalities in multiple sclerosis.

Thirteen patients suffering from multiple sclerosis were analyzed by a Madsen ZO 70 electroacoustic bridge connected to an electronystagmograph through an impedance adaptor. Threshold, amplitude, decay and difference limen of intensity (DLI) of the stapedius reflex were examined for the frequencies 500, 1 000, 2 000 and 4 000 Hz. The difference between standard audiometric results and stapedius reflex data stresses the value of reflex measurements in assessing brain stem pathology.

Acoustic Stimulation↗

PubMedDate not supplied

Multifrequency tympanometry.

The tympanogram shape has been investigated in 290 patients as a function of probe tone frequency (from 200 to 2000 Hz). As the frequency of the probe tone rises, the tympanogram undergoes characteristic modifications which have been grouped, according to their morphologic similarities, in three classes: V, W and inverted-V shape. These three tympanometric configurations are consistently observed both in normals and in some patients with middle ear disorders. Exceptions to this regular behaviour are the pathological pictures of the middle ear in which the structure or the dynamics of the tympano-ossicular system are significantly altered (massive tympanosclerosis, glue ear and cholesteatoma). The frequency interval at which the characteristic tympanometric configurations appear is the most important factor for differentiating pathophysiologic conditions of the middle ear.

Audiometry↗

PubMedDate not supplied

Middle ear mechanics in subjects with rheumatoid arthritis.

The incudo-malleolar and incudo-stapedial joints are true diarthroses and therefore may be subject to the same rheumatic lesions as any other articulation in the body. The existence of this involvement in rheumatoid arthritis (RA), however, is highly controversial. The present study investigates modifications of the mechanical properties of the middle ear in a group of subjects with RA by evaluating the resonance frequency obtained with multiple-frequency tympanometry (MFT). Thirty patients with RA, aged 20 to 68 years (mean age: 45.8 +/- 12.4 years), participated in the investigation. Their data were compared with those obtained in a control group of 48 age-matched subjects. Results obtained in both ears were examined in all subjects. The two groups displayed almost equal hearing levels with mean air conduction thresholds ranging from 10 to 22 dB HL. None of the subjects displayed an air-bone gap greater than 5 dB. Normal resonance frequency, calculated at the 95th percentile from the control group, ranged from 900 to 1250 Hz. Twelve rheumatoid arthritis patients (40 per cent) displayed abnormal resonance values. These findings were monolateral in 9 patients and bilateral in 3. Eleven out of 15 ears with abnormal multiple-frequency tympanometry data were characterized by an increase in resonance and 4 by a decrease. A correlation between abnormal resonance values and more aggressive RA was established. The results of this study suggest that rheumatoid arthritis may involve the incudo-malleolar and incudo-stapedial joints, altering the ossicular mechanics in response to static air pressure modifications. This does not impair sound conduction through the middle ear, but might reduce the protective mechanisms of the middle ear towards high static pressures.

Acoustic Impedance Tests↗

PubMedDate not supplied

ECochG, CNAP and ABR monitoring during vestibular Schwannoma surgery.

Identification of the specific pathophysiological processes and correlation with post-operative hearing are the prerequisites for utilizing electrophysiological audio monitoring techniques in preventing damage to auditory structures during vestibular Schwannoma (VS) surgery. The present paper compares the value of auditory brainstem responses (ABRs), electrocochleography (ECochG) and directly recorded cochlear nerve action potentials (CNAPs) in detecting damage to auditory structures during VS surgery and predicting post-operative hearing. Eighteen consecutive patients operated on for VS, in an attempt at hearing preservation, participated in the investigation. The ipsilateral hearing level (pure tone average [PTA] 0.5-3 kHz) ranged from 10 to 50 dB HL (mean: 30.7 dB HL), with a speech discrimination score equal to or better than 50 per cent. CNAPs furnished the highest predictive score for post-operative hearing. In particular, when a permanent loss of CNAPs occurred the sensitivity and specificity were 100 per cent. The discrepancies between the ECochG and CNAP findings were attributable to high prevalence of cochlear nerve damage, capable of 'disconnecting' the ear from the central auditory pathways, causing persistence of peripheral auditory function and no propagation of the neural input. ABR monitoring was highly sensitive in detecting auditory damage but its prognostic utility was marred by its poor specificity.

Adult↗

PubMedDate not supplied

Improved auditory performance of cochlear implant patients using the middle fossa approach.

The preliminary results of insertion of a cochlear implant via the middle fossa in nine patients with profound bilateral hearing loss are described. Aetiologies included a bilateral radical mastoidectomy cavity, adhesive otitis media, autoimmune inner ear disease, previous cranial trauma, genetic pre-lingual deafness, and otosclerosis. A classic middle fossa approach was adopted. A small cochleostomy measuring 1.5 mm in diameter was performed on the most superficial part of the basal turn. A Nucleus 24M cochlear implant system (Cochlear Corporation) was inserted in four patients, a Lauraflex implant (Philips Hearing Implants) was used in three patients and a Combi 40+ (Med-el) with a double electrode array in two. Single electrode arrays were inserted from the cochleostomy to the cochlear apex and occupied a portion of the basal turn, as well as the middle and apical turns. Double electrode arrays were inserted, one towards the apex and one into the basal turn of the cochlea towards the round window. The receiver stimulator was positioned in a bone well previously drilled in the temporal squama and the electrode carrier was inserted in the fenestrated cochlea. The activity of the inserted electrodes was tested by means of telemetry and intraoperative recording of electrically evoked auditory brainstem responses (EABR). Speech recognition tests, performed over a period of time ranging from one to six months after cochlear implant activation, yielded better results in these patients compared with those obtained in postlingually deaf patients operated on via the traditional transmastoid route. Cochlear implant insertion via the middle fossa approach is a technique which is suitable for the implantation of patients with bilateral radical mastoidectomy cavities, chronic middle ear disease, middle ear malformations, or with partial obliteration of the cochlea in the basal turn. However, the main advantage of inserting the implant through the middle fossa cochleostomy consists in the possibility of stimulating, with the single array, areas of the cochlea, i.e. part of the basal, middle and apical turns, where a greater survival rate of spiral ganglion cells is known to occur. In addition, with the double array total occupation of the cochlea is possible, providing the possibility of replicating the tonotopic organization of the cochlea. This new approach has led to major improvements in speech recognition in all patients compared with patients operated on via the transmastoid approach and, given the present state of the art, may be the elective approach for optimal implantation outcomes.

Adolescent↗

PubMedDate not supplied

Myelin-containing corpora amylacea in vestibular root entry zone.

The vestibular nerve of patients with Meniere's disease and vascular cross-compression syndrome of the root entry zone due to the antero-inferior cerebellar artery was studied. All patients underwent vestibular neurectomy using the retrosigmoid approach, which permits the removal of a long nerve segment. CA were found in the cytoplasm of astrocytes that had not shown signs of degeneration at the central portion of the vestibular root entry zone. No membrane intervened between CA and the surrounding cytoplasm, which was rich in filaments, in particular near the CA, and poorly equipped with other organelles. CA were round or oval inclusions measuring 10-12 microns in diameter. The matrix of the CA was composed of low-density amorphous material, with irregular masses displaying a medium density. A network of randomly oriented filaments and bilaminar, osmiophilic lipid fragments with the same structure and thickness of myelin layers were embedded in the matrix. The CA rich in bilaminar fragments were recognizable also at low magnification for their high electron density. In the astrocytic cytoplasm, near the CA, round or ovalshaped, electron-dense bodies with a multilamellar structure were often visible. These results confirm the hypothesis that CA may contain degenerating myelin embedded in a microenvironment rich in glucose polymers and that CA could be an indicator of neurodegeneration.

Adult↗

PubMedDate not supplied

Stapedius reflex in the monitoring of NaF treatment of subclinical otosclerosis.

Stapedius reflex testing was utilized to monitor the progression of subclinical otosclerosis and evaluate the efficacy of NaF treatment in stabilizing the disease process. The investigation was performed on 93 relatives of patients suffering with surgically confirmed otosclerosis. Subjects were divided into two groups. The first group was treated with NaF in doses ranging from 6 to 16 mg in relation to age. The treatment lasted two years. The second group served as control subjects. Before entering the research, all subjects presented reflex abnormalities represented by a partial or complete on-off effect in one or both ears. Changes in stapedius reflex morphology (from partial to complete on-off and from complete on-off to absence of the reflex) were evaluated at 1 and 2 years. The groups had not developed significant differences at 1 year. At 2 years, the incidence of stable stapedius reflex findings was 91.5% in the treated ears and 77% in the control group. The difference is significant (p less than 0.05) and indicates a stabilizing effect of NaF on the disease process.

Acoustic Impedance Tests↗

PubMedDate not supplied