Biomedical subjects

O Zennaro

Publications and source records attributed to O Zennaro.

9 recordsLinked to original sources

PubMed1998

Short-term effectiveness of medial efferents does not predict susceptibility to temporary threshold shift in the guinea pig.

The 2f1-f2 distorsion product (DPOAE) was measured in conjunction with contralateral noise to evaluate the short-term effectiveness of the olivocochlear efferents in guinea pigs (GPs). An attenuation effect was observed predominantly between 1 and 6 kHz when primary tones were set at 65 dB SPL (contralateral noise of 55 dB SPL). Subsequently, GPs were exposed to a 2 kHz tone of 87 dB SPL for 40 min, using DPOAEs as an estimate of cochlear sensitivity. The response of the cochlea appeared variable. In order to investigate whether effectiveness of efferents plays a role in temporary threshold shift (TTS), the responses of the cochlea to overstimulation were classified into three groups: i) clear cochlear change with complete recovery or actual TTS (group A1); ii) clear cochlear change with incomplete recovery (group A2); iii) mild or no change in cochlear function (group B). No relationship was found between the attenuation effect measured before noise overexposure and the susceptibility to TTS. Animals with a significant attenuation effect could fit into any of the three groups. In addition, the recovery from loud sound exposure was not paralleled with the changes occurring over time in the attenuation effect. Therefore, the conclusion that short-term effectiveness of medial efferents does not predict susceptibility to TTS in the GP is suggested.

Acoustic Stimulation↗

PubMed1995

[Complications of endonasal microsurgery].

Endonasal microsurgery, which has widely proved its efficacy, is not free of complications. They can be due to the technical act itself. In this case they result of surgery mistake and they induce an effraction of the operatory cavity walls. They can also be due to excessive healing of the nasal mucosa. Then they represent the real cause of failure in this type of surgery. The authors present their experience that they compare with similar cases of the literature.

Microsurgery↗

PubMed1995

Piezoelectric middle ear implant preserving the ossicular chain.

The authors developed a research program on piezoelectric middle ear implants. A piezoelectric vibrator was implanted on guinea pigs, enabling piezoelectric auditory-evoked recording. The shape and sizes of a vibrator for humans were determined by a human temporal bone study. These human-type vibrators showed good performances in vitro. A particular vibrator for humans that can be implanted on the stapes' head, without irreversibly interrupting the ossicular chain, was designed by the authors.

Animals↗

PubMed1995

[Development of a piezo-electrical vibrator for middle ear implant. State of research].

Authors develop a piezoelectric vibrator for middle ear implant. Animal experimentation, on guinea pigs, demonstrated the efficiency and good tolerance of this vibrators. A study on human temporal bones led them to design a vibrator implantable on the stapes for humans. The in vitro study of the performances of this vibrators showed an excellent frequency fidelity between 0.5 and 8 kHz, and output levels over 110 dB SPL. A vibrator for humans, implantable on the head of the stapes, without interruption of the ossicular chain was realized. Its study on human temporal bones in implantation position, has begun, in parallel with a theoretical study with a mathematical model.

Animals↗

PubMed1993

[Sudden deafness: a randomized comparative study of 2 administration modalities of hyperbaric oxygenotherapy combined with naftidrofuryl].

Hyperbaric oxygen therapy is one of the numerous therapies which have been proposed in the management of sudden deafness. It is presumptuous to claim the efficiency of any treatment in a pathology where both the origin and the actual rate of spontaneous recovery are unknown. The grounds of therapies are therefore empirical but the need of urgent therapy is dictated by ethics. This study compares the effects of hyperbaric oxygen therapy in two groups of patients; according ot their order in randomization the subjects were treated either at a rate of 1 session or 2 sessions per day. Hyperbaric oxygen therapy was associated with infusion of Naftidrofuryl to counteract the vasoconstrictive effect of increased oxygen pressure in blood. Steroids were also administered simultaneously to avoid, for the same reasons, cerebral oedema. Normovolemic hemodilution (Dauman et al. 1983) was systemically performed in all the patients preliminarily to hyperbaric oxygen therapy, in order to reduce the haematocrit and thus facilitate blood supply. The efficiency and the side effects were similar in the two groups, provided that some principles in the selection and the monitoring of the patients were respected. The rate of 2 sessions of hyperbaric oxygen therapy per day has obvious advantages in view of health policy, but it requires the hospitalization of the patient and should be restricted to the younger subjects.

Adult↗

PubMed1993

[Value of the association of normovolemic dilution and hyperbaric oxygenation in the treatment of sudden deafness. A retrospective study].

The multiple treatments of sudden deafness shows how this pathology still remains quite unknown. The authors present a retrospective study of 87 patients treated by normovolemic hemodilution associated to hyperbaric oxygenation. They obtain a total à 60% of significant recovery (ratio between hearing gain and initial hearing loss, above 25%) and in severe hearing loss (threshold between 70 and 90 dB) 60% of good results (ratio above 50%). The importance of the initial form of audiogram and the presence of dizziness as prognostic factors is not confirmed. On the other hand, the evolution of tinnitus is correlated with the deafness and it is a supplementary means to evaluate the therapeutic efficiency. Moreover the persistence of tinnitus represents an important after effect. Sudden deafness still remains a medical emergency and the delay for carrying out any treatment should be as short as possible. On the other hand it is possible to reduce hospital stay by two sessions of hyperbaric oxygenation per day.

Adolescent↗

PubMed1993

[Implants for the middle ear, development of a human prototype].

Middle ear implants are a new type of hearing aid. Their principle is direct stimulation of the inner ear fluids, by a vibrator implanted in the middle ear. Two technologies are developed by different teams: electromagnetic vibrators, and piezoelectric vibrators. Middle ear implants should be partially implantable (P-MEI), or totally implantable (T-MEI). Authors develop, concurrently with animal experimentation an in vitro method to measure the performance date of the vibrators. The specifications of a future P-MEI have been defined, and vibrators tested with this method. First results encourage to develop this project.

Deafness↗

PubMed1992

[Arachnoid cysts of the cerebellopontine angle].

The authors report two cases of arachnoid cysts of the cerebello-pontine angle. The otologic symptoms were unsteadiness, hearing fall and tinnitus. In the first case, the patient who presented a cerebellar syndrome was operated. Afterwards the hearing felt and he developed a transient hydrocephalus. The symptoms disappeared in 9 months. In the second cas, the patient was not operated. She was treated medically and supervised. Then the symptoms disappeared too. The authors review the paraclinic exams especially MR, relevant to the diagnosis and discuss the opportunity of a surgical operation.

Adult↗

PubMed1992

[Ankyloglossum superius: apropos of a case].

The authors report a rare observation of ankyloglossum superius i.e. the attachment of the tip of the tongue to the anterior part of the palate, with an ectrodactyl of the fingers and toes. Following a review of the literature, this provide an opportunity to recall this pathology, the physiopathogenesis of which remains unknown falling within syndromes of malformation affecting both the mouth, face and limb, namely orofacio-digital syndromes and syndromes of hypogenesis of the mouth, jaw and limbs.

Fingers↗