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M Rolando

Publications and source records attributed to M Rolando.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Vestibular function and cochlear implant.

The authors illustrate their personal experience relating to 32 patients, aged between 12 and 74 years, undergoing cochlear implant, in whom vestibular reflexes were evaluated before and after surgery. This series did not include cases of areflexia, but only 1 case of reduced vestibular reflexia consequently to surgery. In this case, owing to the probable intervention of central compensation processes, labyrinthine hyporeflexia never became clinically significant. These personal results enable the authors to affirm that preoperative vestibular reflexes do not offer elements able to influence the choice of the ear in which to perform the cochlear implant. In the series of patients reported by the authors, a cochleostomy by removal of the floor of the round window niche, following the suggestions of O'Leary et al., always headed the electrode implant. This contrivance may reduce or eliminate the negative effects on vestibular receptors indirectly caused by the consequent and inevitable alteration of perilymph pressure produced by the implant.

Adolescent↗
PubMedDate not supplied

Influence of stimulus duration and intensity on acoustic reflex parameters.

Four acoustic reflex parameters (latency, duration, amplitude, recruitment time) in response to stimuli lasting 1 000 to 50 msec with an initial intensity of 95 dB SPL p.e. were studied in four sets of experiments. In each set of experiments, each halving of the stimulus duration was accompanied by a 3, 4, 5 and 6 dB SPL p.e. increase respectively (exchange rates: 3, 4, 5 and 6 dB SPL p.e.). It was found that latency was dependent on the threshold only and unaffected by either duration and intensity. Amplitude and recruitment time were mainly determined by energy content of the stimulus, whereas duration of contraction was solely dependent on the stimulus duration. These experiments also demonstrate that, with reference to stimuli employed, an increase of 3 dB SPL p.e. each halving of the stimulus duration is unable to maintain unchanged the environmental acoustic energy reaching the inner ear.

Acoustic Stimulation↗
PubMedDate not supplied

[The usefulness of computer tomography in planning cochlear implant surgery].

In recent years, technical progress has created new complex acoustic implants which send an electrical stimulus to the eighth cranial nerve through one or more electrodes inserted through the round window into the scala tympani of the cochlea. The abnormal--mostly osteosclerotic--processes which cause deep hearing loss may prevent electrode insertion. Therefore, internal ear anatomy must be detailed, which is essential to assess the feasibility of surgery and, if surgery is indicated, to plan it properly. High resolution CT (HRCT) was performed on 79 patients to study cochlear patency, round window shape and patency, degree of temporal bone pneumatization and the proximity of vascular structures (carotid artery and jugular vein). On the basis of HRCT results, 14 of 79 patients were excluded from surgery. Comparing HRCT with surgical findings, the authors conclude that HRCT is the method of choice to examine the candidates to cochlear implant thanks to its high spatial resolution and excellent depiction of even the smallest structures. Its only limitation is that it fails to assess the lack of patency of the cochlear canal due to fibrosis, which is not associated with demonstrable density changes (3 of 19 surgical patients). This problem may be solved by submitting the potential surgical candidates to MRI.

Adult↗