Background and objectives: Adherence to therapeutic guidelines for the treatment of hyponatremia becomes difficult when water diuresis emerges during therapy. The objective of this study was to assess the effectiveness and safety of desmopressin acetate as a therapeutic agent to avoid overcorrection of hyponatremia and to lower the plasma sodium concentration again after inadvertent overcorrection.Design, setting, participants, & measurements: Retrospective chart review was conducted of all patients who were given desmopressin acetate during the treatment of hyponatremia during 6 yr in a 528-bed community teaching hospital.Results: Six patients (group 1) were given desmopressin acetate after the 24-h limit of 12 mmol/L had already been reached or exceeded; correction was prevented from exceeding the 48-h limit of 18 mmol/L in five of the six. Fourteen patients (group 2) were given desmopressin acetate in anticipation of overcorrection after the plasma sodium concentration had increased by 1 to 12 mmol/L. In all 14 patients who were treated with desmopressin acetate as a preventive measure, correction was prevented from exceeding either the 24-or 48-h limits. After desmopressin acetate was administered, the plasma sodium concentration of 14 of the 20 patients fell by 2 to 9 mmol/L. In all six group 1 patients and in five of the group 2 patients, the plasma sodium concentration was actively lowered again by the concurrent administration of desmopressin acetate and 5% dextrose in water; no serious adverse consequences from this maneuver were observed.Conclusion: Desmopressin acetate is effective in preventing and reversing inadvertent overcorrection of hyponatremia.

The purpose of this study was to quantify perceived hypernasality in children. One-third octave spectra of the isolated vowel [i] were obtained from 32 children with cleft palate and 5 children without cleft palate. Four experienced listeners rated the severity of hypernasality of the 37 speech samples using a 6-point equal-appearing interval scale. When the average 1/3-octave spectra from the hypernasal group and the normal resonance group were compared, spectral characteristics of hypernasality were identified as increased amplitudes between F1 and F2 and decreased amplitudes in the region of F2. Based on the findings of the children's speech, 36 speech samples with manipulated spectral characteristics were used to minimize the influences of voice source characteristics on perceived hypernasality. Multiple regression analysis revealed a high correlation (R = 0.84) between the amplitudes of 1/3-octave bands (1 k, 1.6 k, and 2.5 kHz) and the perceptual ratings. Increased amplitudes of bands between F1 and F2 (1 k, 1.6 kHz) and decreased amplitude of the band of F2 (2.5 kHz) was associated with an increasing perceived hypernasality. These results suggest that the amplitudes of the three 1/3-octave bands are appropriate acoustic parameters to quantify hypernasality in the isolated vowel [i].

Aerodynamic and temporal characteristics of velopharyngeal function were determined for 42 adult male and female speakers. All subjects produced the word "hamper" at self-determined loudness levels and rates of speaking. Measurements of intraoral air pressure, nasal airflow, and estimates of velopharyngeal orifice size were obtained during production of the /m/ and /p/ segments. Volume measurements of nasal airflow were determined for the entire word, the /m/ segment, and the segments preceding /m/. Fifteen timing measures associated with the pressure-flow events of the nasal-plosive sequence were also determined. Results indicated that males generated significantly higher levels of peak intraoral air pressure than females during /p/. Male speakers also exhibited a significantly shorter interval in the rise of oral pressure associated with the /p/ segment. Male and female speakers, however, exhibited similar levels of anticipatory coarticulation as reflected by nasal air volume measurements. Finally, variability of selected measurements within speakers suggested that temporal aspects of velopharyngeal function were more constrained than aerodynamic aspects. The results are discussed relative to (a) sex differences in respiratory and velar function and (b) normative data for adult speakers.

Research examining physiologic and acoustic characteristics of culturally diverse populations is sorely needed, but rarely reported. The major aim of this study was to quantify vocal tract dimensional parameters (oral length, oral volume, pharyngeal length, pharyngeal volume, total vocal tract length and total vocal tract volume) of adult male speakers from three different racial populations (White American, African American, and Chinese). It also attempted to investigate if volumetric differences in the speakers' vocal tracts, like length differences, would contribute to the acoustic characteristics of these speakers from different races. The findings of this study support the hypothesis that speakers from different races may have morphological differences in their vocal tract dimensions, and these morphological differences (especially volumetric differences) could be partially responsible for the formant frequency differences in a vowel sound void of specific language/dialectal impacts. The study has provided speech scientists, speech-language pathologists, linguists and other health professionals with a new and preliminary acoustic and physiological database for adult male speakers from these three different races.

Transient voice change associated with endotracheal intubation has generally been attributed to vocal fold trauma. To assess the role of altered vocal fold function in transient voice change, a study was designed to evaluate the audioacoustic, endoscopic, and laryngostroboscopic characteristics of the postintubation voice. Vocal function of 10 patients undergoing short-term outpatient surgical procedures using general anesthesia and endotracheal intubation were studied preoperatively and postoperatively. A second group of 10 patients that did not have surgery or general anesthesia was used as an age-matched control. Fundamental frequency, frequency perturbation, electroglottography, endoscopy (including laryngeal stroboscopy), and subjective speech analysis by experienced listeners were used to assess vocal function. No consistent differences in fundamental frequency were observed, although patient-to-patient variation was marked. Statistically significant increases in cycle-to-cycle fundamental frequency variation (jitter) were found postoperatively in the majority of the postintubation patients (P less than 0.05). Electroglottography, laryngeal endoscopy, and stroboscopic laryngoscopy did not demonstrate consistent changes in glottic mucosal function. Listener judgments characterized the postintubation voice change by decreased intensity, increased roughness, and lowered affect without consistent changes in pitch. The perception of decreased affect in the voices (characterized by reduction in pitch variation, vocal stress, and increases in pause times) was a strong perceptual marker for change in the post-intubation voice. Objective measures of laryngeal function suggest that the glottic contribution to postintubation voice change is minimal and that this dysphonia is probably multifactorial.