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Biomedical subjects

M Fabiani

Publications and source records attributed to M Fabiani.

At least 55 records · Page 3Linked to original sources
PubMed1997

Role of transient-evoked otoacoustic emissions for hearing preservation in acoustic neuroma surgery.

OBJECTIVE: This study aimed to assess whether transient-evoked otoacoustic emissions (TEOAEs), which are known to be expressions of an intact cochlear function, could be useful for the rationale of hearing preservation in acoustic neuroma (AN) surgery. STUDY DESIGN: The TEOAEs were measured before, during, and after surgery in a consecutive series of patients affected by cerebellopontine angle tumors. SETTING: The study was performed at the Department of Otolaryngology, University "La Sapienza" of Rome. PATIENTS: Five patients with AN and one with a meningioma totally involving the Cochlear (VIII) nerve. INTERVENTION: Retrosigmoid approach on the ground of the limited AN size (within 20 mm) and the 30/70 rule, as proposed by the American Academy of Otolaryngology-Head and Neck Surgery nomogram. Two patients also were selected despite a poor hearing level and the absence of TEOAEs. MAIN OUTCOME MEASURES: Preoperative and postoperative pure tone audiometry compared with TEOAEs. Intraoperative TEOAEs were compared with electrocochleographic findings. RESULTS: The TEOAEs were found to be present also in patients with AN with poor pure-tone average (PTA) threshold (i.e., > 75 dB). Intraoperatively, TEOAEs recording showed to be markedly affected by the environmental noise as well as by specific intraoperative maneuvers, such as drilling of the internal auditory canal or tumor removal or both. In the three patients in whom hearing successfully was preserved. TEOAEs were present in the first postoperative days, despite a temporary deterioration of the PTA threshold. CONCLUSIONS: The intraoperative use of TEOAEs showed to be scarcely reliable, whereas their presence in the preoperative assessment of patients with AN could lead to an extended number of patients to be selected for hearing-preservation surgery. Finally, an early postoperative identification of TEOAEs may be considered a favorable prognostic sign for foreseeing a delayed pure-tone hearing threshold recovery.

Acoustic Stimulation↗
PubMed1996

Immunological activation markers in the serum of African and European HIV-seropositive and seronegative individuals.

OBJECTIVE: The concentration of type 1 and type 2 cytokines and fibroblast-associated apoptosis-1 soluble receptor (sAPO-1/Fas) was analysed in the sera of Ugandan and Italian HIV-1-seropositive and seronegative individuals. The data were compared to determine whether the immunological status of these groups was different. METHODS: Sixty-seven Ugandan and 30 Italian HIV-positive patients were analysed and stratified according to CD4 counts (group 1, > 500 x 10(6)/l; group 2, 200-500 x 10(6)/l; group 3, < 200 x 10(6)/l). Sera from 15 Ugandan and 11 Italian HIV-negative blood donors were also analysed. Serum concentration of type 1 cytokines [interleukin (IL)-2, IL-12, and interferon (IFN)-gamma] and type 2 cytokines (IL-4 and IL-10), and sAPO-1/Fas were measured by enzyme-linked immunosorbent assay. RESULTS: Serum levels of IL-2, IFN-gamma and IL-10 but not of IL-4 and IL-12, were elevated in HIV-positive group 1 and 2 Africans compared with HIV-positive Italian individuals. IL-4 was mildly augmented in HIV-positive group 3 African patients. Serum concentration of sAPO-1/Fas was reduced in HIV-positive Africans compared with HIV-positive Italian individuals. Finally, serum levels of IL-2 and IL-10 were increased and sAPO-1/Fas reduced when sera of HIV-negative African healthy controls were compared with their Italian counterparts. The ratio of type 1/type 2 cytokines was roughly 1.0 in HIV-negative African controls, and much greater than 1.0 in HIV-negative Italian controls. CONCLUSIONS: These preliminary findings indicate that immune activation is present in African HIV infection. Furthermore, these data raise the possibility that abnormal immune activation and increased susceptibility to antigen-induced cell death is present even in HIV-negative African controls.

AIDS-Related Opportunistic Infections↗
PubMed1996

Naming norms for brief environmental sounds: effects of age and dementia.

Brief nontonal sounds are used in electrophysiology in the novelty oddball paradigm. These sounds vary in the brain activity they elicit and in the degree to which they can be identified, named, and remembered. Because ease of sound identification may influence sound processing, naming and conceptual norms were determined for 100 sounds for 77 young adults (Experiment 1). Naming ability decreases in normal and pathological aging. Therefore, norms were also derived for older adults (Experiment 2) and for probable Alzheimer's disease patients (Experiment 3). With respect to the young adults, perseverative naming behavior increased in these groups, and sound and picture naming performance were correlated. In Experiment 4, the sound-naming performance of children aged 5-6, 9-11, and 14-16 years was compared. Name and conceptual agreements improved with age, whereas perseverative behavior decreased. These normative data should be useful in guiding sound selection in future studies and help clarify the relationships between sound naming and other variables, including direct and indirect memory performance.

Acoustic Stimulation↗
PubMed1995

Encoding processes and memory organization: a model of the von Restorff effect.

The mechanisms underlying the improved recall of isolated events (von Restorff effect) were investigated. Participants studied lists of stimuli containing a physical and a semantic isolate while performing a physical task or a lexical decision task. The physical-task group showed a physical but not a semantic isolation effect (IE) in free recall, whereas the lexical-decision group displayed both types of IEs. The recall of the isolates was independent of that of the other words, and isolates were usually reported separately from other words in the list. Event-related potentials recorded at encoding predicted the recall of both types of isolates. In recognition tests, the IE was obtained only when the encoding context was reinstated. These results are consistent with a model of the IE that stresses the role of the encoding processes immediately following the presentation of distinctive events, and that postulates interactions between these processes and subsequent elaboration of the stimuli.

Adult↗
PubMed1995

Changes in brain activity patterns in aging: the novelty oddball.

A decrease in the frontal lobes' efficiency is supposed to play a role in age-related changes in cognitive function. If frontal lobes are involved in the maintenance of working memory, the elderly may require increased frontal activity because of more rapid memory decay. This is consistent with the fact that the P3 component of the event-related potential (ERP) has a more frontal orientation with increasing age. However, frontally distributed P3s are also observed in young people when novel stimuli are unexpectedly presented in an oddball paradigm. Young and old subjects were run in an auditory novelty oddball in which ERPs were recorded from 30 scalp sites. The young adults' P3s showed either a posterior (targets) or more frontally oriented (novels) scalp focus. The elderly were less accurate in their memory for the novel stimuli, and their P3s showed anterior and posterior foci to both targets and novels. The young adults' target P3s changed over time from a frontal to a posterior focus, whereas the old adults' did not. These results are consistent with decreased ability of the elderly to maintain the templates needed for stimulus categorization.

Adult↗
PubMed1995

Shades of gray matter: noninvasive optical images of human brain responses during visual stimulation.

Recent theories about human brain function emphasize the need for imaging methods that allow the study of dynamic interactions among different structures. In this paper, we report on a new technique, based on the measurement of parameters of migration of near-infrared photons, that yields functional images of the human occipital cortex, combining a spatial resolution of 0.5 cm and a temporal resolution of 50 ms. This technique appears to be suitable for studying the dynamics of cortical activation.

Adult↗
PubMed1994

Feasibility of intracranial near-infrared optical scanning.

Light injected at a point on a surface of a scattering medium is emitted at the surface after traveling a quasisemicircular path deep into the medium. This phenomenon can be exploited to detect objects immersed in the medium from time-resolved measurements of light intensity at the surface. Our experiments on model systems demonstrate that absorbing objects, surrounded by bone and other scattering material, can be detected. The technique yields surface images of absorbing objects submerged in a scattering medium. Images of the same phantoms inside the cavity of a skull can be obtained by the same technique.

Brain↗
PubMed1993

Evoked otoacoustic emissions in the study of adult sensorineural hearing loss.

In the present report the applicability of evoked otoacoustic emissions (EOAEs) in the clinical field for studying adult sensorineural hearing loss is discussed. Three topics are considered: (1) EOAEs replacing a testing procedure, (2) EOAEs integrating into the test battery thus validating the diagnostic outcome, (3) EOAEs implementing new diagnostic possibilities. The authors conclude that: (a) EOAEs could only be applied to replace pure-tone audiometry for assessing functional deafness, (b) EOAEs are a useful diagnostic tool complementing the audiological test battery, (c) EOAEs are a unique method that studies the efferent auditory pathways. It is suggested that EOAEs should be applied as a routine audiological test for adult sensorineural hearing loss not only in cases with a well-defined diagnostic profile, but also in those cases with a less clear diagnostic pattern, in order to collect more data and possibly gain better knowledge about the pathophysiology of the inner ear.

Acoustic Stimulation↗
PubMed1992

Functional correlates of a three-component spatial model of the alpha rhythm.

We applied a three-component (temporal, occipital and parietal) spatial model to EEG data obtained from 46 young and 11 elderly subjects. With closed eyes the mean alpha frequency was 9.51 Hz for the temporal, 9.88 Hz for the occipital and 10.14 Hz for the parietal component. The power of the occipital component was larger than that of the others. With open eyes it was reduced to the same level as the temporal and parietal components. The power of the occipital component decreased significantly with age.

Adult↗
PubMed1990

Effects of mnemonic strategy manipulation in a Von Restorff paradigm.

Subjects were instructed to use either rote or elaborative strategies to memorize words in a Von Restorff paradigm. When instructed to use rote strategies, subjects displayed a higher Von Restorff effect and a lower recall performance than when instructed to use elaborative strategies. Furthermore the amplitude of the P300 component of the event-related brain potential predicted subsequent recall only when subjects used rote strategies. When subjects used elaborative strategies, the relationship between P300 amplitude and subsequent recall was not observed. These results confirm and expand, in a within-subjects design, the results reported by Karis, Fabiani and Donchin (1984) who capitalized on different strategies used by different subjects. These results also lend support to a 3-phase model of the von Restorff effect.

Adolescent↗
PubMed1990

A placebo-controlled crossover trial of nimodipine in pediatric migraine.

An 8-month, double-blind, placebo-controlled crossover trial was carried out on the use of nimodipine in migraine prophylaxis in 37 patients aged 7 to 18 years old. After a 4-week medication-free run-in period, 19 subjects (Group 1) received a placebo while 18 (Group 2) received nimodipine (10-20 mg t.i.d., according to body weight), for 12 weeks. After a 4-week wash-out period, the groups switched therapy for a further 12 weeks. 30 patients completed the trial and the number of dropouts was comparable in the 2 groups. The only side-effect during nimodipine treatment was mild abdominal discomfort (3 cases). The treatments were evaluated on the basis of frequency and duration of attacks. There was a significant reduction in both parameters during the first period of treatment. During the second period of treatment, nimodipine proved to have a significantly greater effect than the placebo with regard to frequency, whereas the response was similar with the placebo as regards duration of attacks. The latter parameter shows a significant decrease during the treatment periods, regardless of type of therapy.

Adolescent↗
PubMed1984

Mathematical expression of relationship between auditory brainstem transmission time and age.

Brainstem transmission time (BTT) was studied in 71 subjects ranging in age from one day to 29 years in order to find a mathematical expression to best describe the relationship between BTT and age. The mathematical function which relates BTT to age is exponential. Using this data, the BTT confidence limit was calculated for subjects from birth through to eight years. Repeated recordings of auditory brainstem responses were performed in several children as they grew older and these verified the normal maturational processes of the brainstem structures in the developing infant and young child.

Age Factors↗
PubMed1984

External ear canal exostosis and aquatic sports.

Many reports suppose that the development of aural exostosis depends on the action of an irritative stimulus like frequent and repeated cold water contact. This survey studies the incidence of this lesion in a group of 433 athletes practicing aquatic sports on a highly competitive level. Among these, water activities like sailing and deep-sea diving, which up to now were never considered, were also studied. 32 exostoses were found to affect 12 subjects monolaterally and 20 subjects bilaterally. Not one of a control group of 476 athletes was found to be affected by aural exostosis. For each athlete in this study the following parameters are considered: age and sex, type of sport, total amount of hours spent in water contact, aural pathology history and otoscopic findings. The authors suggest the existence of facilitating factors other than total water contact time, as shown by the absence of a precise correlation between this parameter and the presence of the aural hyperostotic lesion.

Diving↗
PubMed1983

Wave VII recognizability in brainstem auditory-evoked potentials.

Brainstem auditory-evoked potentials (BAEP) recorded with a far-field from the scalp technique are generally described as 7 positive waves in the initial post-stimulatory 10 ms period. Also at high stimulus intensities, the Jewett wave VII appears to be undetectable in the majority of normal subjects. We present an original recording method to reproducibly detect this late BAEP wave. 48 normal ears were examined and wave VII was detectable in all the recordings with clicks delivered at an intensity of 75 dBHL.

Adult↗