Changes in Vocal Fold Morphology During Singing Over Two Octaves.

OBJECTIVE: Vocal folds are widely assumed to only elongate to raise vocal pitch. However, the mechanisms seem to be more complex and involve both elongation and tensioning of the vocal folds in series. The aim of the present study was to show that changes in vocal fold morphology depend on vocal fold elongation and tensioning during singing. STUDY DESIGN: This was a prospective study. METHODS: Forty-nine professional female singers (25 sopranos, 24 altos) were recruited and three-dimensional laryngeal images analyzed in a coronal view derived from high-resolution computed tomography scans obtained at the mean speaking fundamental frequency (ƒ0) and one (2ƒ0) and two octaves (4ƒ0) above ƒ0. RESULTS: The vocal fold angle, defined by a tangent above and below the vocal folds, was 58° at ƒ0, 47° at 2ƒ0, and 59° at 4ƒ0. CONCLUSION: The decreased caudomedial angle of the vocal fold from ƒ0 to 2ƒ0 (change in muscle belly from ";fat" to "thin") and increased angle from 2ƒ0 to 4ƒ0 (from "thin" to "fat") strongly supports the hypothesis that the vocal folds elongate and then tension when singing from ƒ0 to 4ƒ0. This is the first study to show this relationship in vivo.

Evaluation of clinical tests to assess perfusion in chronic critical limb ischemia.

BACKGROUND: Evaluation of macro- and microcirculatory tests to confirm diagnosis, and recognize perfusion changes in chronic critical limb ischemia (CLI). PATIENTS AND METHODS: Forty-two consecutive patients with CLI examined at the University Hospital Bern, with 21 included in this prospective follow-up analysis. Patients underwent serial clinical examinations, and assessment of the macro- (ankle arterial pressure [AP], great toe pressure [TP], oscillography) and microcirculation (transcutaneous partial oxygen pressure [tcPO2] recumbent, sitting, O2-inhalation; capillary microscopy) at baseline, 6 weeks after revascularization (group 1; [n = 11]), or after 10 weeks in patients unsuitable for revascularization (group 2; [n = 10]). Clinical improvement was considered to indicate increased perfusion. RESULTS: Eleven patients with revascularization (11/11), and 2 without revascularization (2/10) showed clinical improvement. AP measurements were not reliable or feasible in 9 (43%), TP in 4 patients (19%), respectively. All measurable pressures were in accordance to clinical course. Oszillography gave a moderate perception of perfusion changes. Baseline tcPO2 levels were critical (< 30 mmHg) in all 21 patients, whereas follow-up gave poor correlation with the clinical course. Reliability to detect perfusion changes increased by adding provocation manoeuvers in patients with clinical improvement (39% [5/13] recumbent, 77% [10/13] sitting, 85% [11/13] O2-inhalation). Capillary microscopy revealed a relevant pathology at the forefoot level in all patients with feasible examinations (18/21), and significant improvements according to the clinical course in 92% of patients (12/13). CONCLUSIONS: TP measurements represented most reliable test to confirm diagnosis and disclose improved perfusion in CLI. TcPO2 measurements in recumbent position gave unreliable results, improved by provocation manoeuvers. Capillary microscopy was reliable, but time consuming and limited by anatomical restrictions.

Quantitative (1)H magnetic resonance spectroscopy of myoglobin de- and reoxygenation in skeletal muscle: reproducibility and effects of location and disease.

1H-magnetic resonance spectroscopy ((1)H-MRS) of deoxymyoglobin (DMb) provides a means to noninvasively monitor the oxygenation state of human skeletal muscle in work and disease. As shown in this work, it also offers the opportunity to measure the absolute tissue content of DMb, the basic oxygen consumption of resting muscle, and the reperfusion characteristics after release of a pressure cuff. The methodology to determine these tissue properties simultaneously at two positions along the calf is presented. The obtained values are in agreement with invasive determinations. The reproducibility of the (1)H-MRS measurements is established for healthy controls and patients with peripheral arterial disease (PAD). A location dependence in axial direction, as well as differences between controls and patients are demonstrated for all parameters. The reoxygenation time in particular is expected to provide a means to quantitatively monitor therapies aimed at improving muscular perfusion in these patients.

Ototoxicity of ear drops: a clinical perspective.

Although experimental data confirm the presence of ototoxicity due to topical ear drops, the clinical relevance still remains debatable. Only few case reports document sensorineural hearing loss (SNHL) attributable to ototopical preparations in patients with chronic otitis media. A careful review of 134 patients charts evaluated between 1953 and 1995 for possible antibiotic related ototoxicity revealed two patients with bilateral profound SNHL attributable to excessive administration of framycetin- and polymyxin-containing ear drops in the presence of tympanic membrane perforation. Although ototopical preparations are widely used, they rarely induce SNHL. The authors emphasize patient education, application of topical ear drops using soaked gauze strips, and documentation of the patients hearing status at the beginning of the treatment regimen.