Biomedical subjects

Christian Ahmarani

Publications and source records attributed to Christian Ahmarani.

2 recordsLinked to original sources

PubMed2006

Physiologic features of vocal fatigue: electromyographic spectral-compression in laryngeal muscles.

OBJECTIVES: This study addresses the problem of defining observable attributes of "vocal fatigue" as a physiologic condition. The aim was to determine the applicability of electromyography (EMG) spectral compression in observing fatigue in laryngeal muscles arising from prolonged vocal effort. STUDY DESIGN: Single institution, nonrandomized, prospective analysis of subjects evaluated in an academic, tertiary care center. METHODS: In adapting EMG techniques, we report pretest observations that bear on the choice of voicing tasks serving to induce and estimate muscle fatigue and the selection of muscles that are particularly involved in effortful vocalization. On this basis, an experiment was designed where intramuscular EMG was used to record lateral cricoarytenoid potentials of seven subjects at regular intervals across a 12 to 14 hour period (50 samples per subject). Between each of these samples, the participants were required to produce loud speech for 3 minutes with peaks of 74 dBA at 1 meter. RESULTS: The results show fatigue-related spectral compression for all subjects and nonlinear changes across time indicating critical values beyond which fatigue is persistent. CONCLUSION: Spectral compression appears to present a robust attribute of fatigue-related changes in muscles involved in vocalization. There are several implications with respect to research on the prevention of acquired voice pathologies.

Adult↗

PubMed2006

Orbital decompression: cadaver study.

BACKGROUND: Patients with Graves' ophthalmopathy may need surgical treatment to alleviate ophthalmologic complications. The degree of reduction in proptosis following surgical intervention remains difficult to predict. OBJECTIVES: To elaborate a human model using cadaver orbits to study surgical management of Graves' ophthalmopathy. To evaluate quantitatively the contribution of each orbital wall decompression and their combinations in reduction in proptosis. To improve the ability to predict the degree of proptosis reduction according to the wall(s) chosen for decompression. METHODS: Artificial exophthalmos was created in 12 cadavers' orbits by injecting a polysaccharide gel in the peribulbar and retrobulbar tissues. Proptosis reduction was measured following successive orbital decompression. RESULTS: Decompression of one wall produced a nonstatistical significant reduction in proptosis. The combination of the medial and lateral walls significantly reduced the proptosis by a mean of 4.2 mm. Three-wall decompression gave a mean significant reduction of 6.6 mm, and when combined with the advancement of the lateral wall, it reduced proptosis by 12.5 mm. CONCLUSIONS: We created an experimental model for research and didactic purposes for surgical mangement of Graves' ophthalmopathy. With this model, to obtain 5 mm or more of proptosis reduction, three-wall decompression is required. Advancement of the lateral wall achieved a further reduction in proptosis. For a proptosis reduction of less than 5 mm, decompression of the medial and lateral walls is appropriate.

Cadaver↗