Arytenoid adduction as an adjunct to type I thyroplasty for unilateral vocal cord paralysis.

BACKGROUND: Surgical management of unilateral vocal cord paralysis has evolved over the last three decades. The recent use of type I thyroplasty has resulted in improvements in voice, swallowing, and respiration. The study was performed to evaluate our experience in 28 patients undergoing arytenoid adduction as part of their surgical rehabilitation of unilateral vocal cord paralysis. METHODS: Patients undergoing arytenoid adduction with or without silastic medialization for unilateral vocal cord paralysis were entered into a prospective data base. Evaluation included symptomatic improvement in hoarseness, aspiration, dysphagia, dyspnea, and the radiographic documentation of pneumonia. Objective evaluation included mean phonatory air flow and acoustic analysis. Complications associated with surgery were recorded. RESULTS: A satisfactory result was obtained in 27 of 28 (96%) patients. By symptom, improvement in hoarseness was evident in 96%, dyspnea 80%, dysphagia 94%, and aspiration 84%. Improvements in phonatory flow rate (p < .001), estimated mean laryngeal airway resistance (p < .001), and maximally prolonged phonation (p < .01) were identified. Complications occurred in 18% and consisted of local wound sepsis (n = 1), hematoma (n = 1), seroma (n = 1), and transient airway edema (n = 2). There were no episodes of airway obstruction requiring tracheostomy or implant extrusion. CONCLUSIONS: Arytenoid adduction as part of type I thyroplasty is a safe and effective procedure. Subjective analysis confirms marked improvement in laryngeal function in the form of speech, swallowing, and respiration. Objective analysis confirms improvement in voice parameters. Future directions will focus on determination of those patients best served by arytenoid adduction.

Acoustic and physiologic characteristics of inspiratory phonation.

Voice produced on inhaled air is a form of phonation that has received relatively little attention despite its apparent usefulness in the assessment of vocal function. This preliminary investigation was designed to describe the general characteristics of vocalization driven by an ingressive phonatory airflow. Vocal fundamental frequency (F0), electroglottographic (EGG), and airflow measures were examined in 16 normal men and women, who alternated between inspiratory and expiratory voice. Mean F0 routinely increased during inspiratory voice segments, shifting on average 5.1 semitones above the subjects' comfortable expiratory voice frequency. EGG data showed inspiratory voice to be associated with a more symmetrical pattern of vocal fold contact characterized by a prolonged interval of increasing contact. Both short-term F0 variability (jitter) and EGG amplitude perturbation were significantly higher during inspiratory voice. Stroboscopic examination of four of the subjects showed caudal displacement of the larynx and lengthened vocal folds associated with inspiratory phonation. The absolute airflow rate was significantly greater for inspiratory phonation, on average 48.5% higher than during normal expiratory voice. It was also found that both inspiratory pulse and falsetto vibratory patterns could be produced by at least some of the subjects, indicating some control over the mode and frequency of vocal fold vibration when driven by an ingressive airflow.

Vocal fundamental frequency measures as a reflection of tumor response to chemotherapy in patients with advanced laryngeal cancer.

The fundamental frequency (F0) characteristics of 19 male patients with advanced laryngeal cancer, treated with cisplatin-based chemotherapy as part of a Larynx Preservation Protocol (LPP), were measured before each of three cycles of chemotherapy received before definitive radiotherapy (RT). In these select patients, for whom chemotherapy resulted in > or = 50% decrease in the tumor bulk, it was found that mean F0 was essentially unaffected by the disease and did not change over the course of chemotherapy, although the cycle of their treatment could be differentiated by both speaking F0 variability (pitch sigma) and F0 perturbation (jitter). Although these measures failed to distinguish between those patients showing a complete response (CR) (no measurable disease) versus a partial (PR) (residual) tumor response at the primary disease site, the significant changes observed in both groups indicate that frequency variation measures could prove valuable in the documentation of tumor response to nonsurgical therapeutic intervention if the voice is directly affected. Additional assessment of 15 age- and disease-matched patients who showed minimal or no primary response to the chemotherapy showed no significant change in any of the frequency measures after one chemotherapy cycle, suggesting that vocal improvement seen in the successful chemotherapy patients was not due to postbiopsy healing or other systemic influence unassociated with tumor reduction.

Vocal cord medialization for unilateral paralysis associated with intrathoracic malignancies.

Patients with unilateral vocal cord paralysis from intrathoracic malignancies may have significant dysfunctions of speech, swallowing, ventilation, and effective coughing as a result of inadequate compensation of the nonparalyzed cord. In patients with already compromised pulmonary function, aspiration can be a life-threatening event. Sixty-three patients with intrathoracic malignancies required surgical correction of vocal cord paralysis. Primary pathology included lung cancer (49), esophageal cancer (nine), and miscellaneous tumors (five). Symptoms included hoarseness (62), dyspnea (21), aspiration (26), weight loss (19), dysphagia (14), and pneumonia (14). The surgical procedures included medial displacement of the vocal cord with silicone elastomer (48), temporary Gelfoam injection (seven), and Teflon (polytetrafluoroethylene) injection (eight) to move the affected cord to a medial position. In 11 patients, the operation was performed in the acute postoperative setting to improve pulmonary toilet. Symptomatic improvement was noted in the following proportions of affected patients: hoarseness, 92%; dyspnea, 90%; dysphagia, 93%; aspiration, 92%; pneumonia, 93%; and weight loss, 47%. Overall success rate of the intervention was 57 of 63 patients (90%). All 11 patients treated in the acute setting had immediate improvement. A variety of complications occurred in 17% of patients. Surgical management of vocal cord paralysis in patients with intrathoracic malignancies prevents life-threatening pulmonary complications in the acute postoperative setting. In chronic situations, it provides patients with improved speech, swallowing, and pulmonary function, resulting in improved quality of life, even for patients not cured of their disease.

Vocal stability and vocal tract configuration: an acoustic and electroglottographic investigation.

Previous studies have reported differences in vocal fundamental frequency perturbation (jitter) and amplitude perturbation (shimmer) measures as a function of vowel type. However, it is not clear from those studies whether these effects derive from modifications in the shape of the vocal tract or from intrinsic vowel differences in mean fundamental frequency and vocal amplitude. The present study sought to address this issue using simultaneously obtained acoustic and electroglottographic (EGG) signals. Ten normal adult men and 10 normal adult women prolonged three maximally stable productions of the vowels [symbol: see text]. Vocal sound pressure level was maintained at 74 +/- 4 dB, while mean fundamental frequency was maintained at 110 and 220 Hz +/- 0.5 st for the male and female subjects, respectively. Results indicated that when vocal frequency and intensity are controlled, acoustic and EGG measures of mean jitter and shimmer do not show a significant vowel effect.

Speaker race identification from acoustic cues in the vocal signal.

One-second acoustic samples were extracted from the mid-portion of sustained /a/ vowels produced by 50 black and 50 white adult males. Each vowel sample from a black subject was randomly paired with a sample from a white subject. From the tape-recorded samples alone, both expert and naive listeners could determine the race of the speaker with 60% accuracy. The accuracy of race identification was independent of the listener's own race, sex, or listening experience. An acoustic analysis of the samples revealed that, although within ranges reported by previous studies of normal voices, the black speakers had greater frequency perturbation, significantly greater amplitude perturbation, and a significantly lower harmonics-to-noise ratio than did the white speakers. The listeners were most successful in distinguishing voice pairs when the differences in vocal perturbation and additive noise were greatest and were least successful when such differences were minimal or absent. Because there were no significant differences in the mean fundamental frequency or formant structure of the voice samples, it is likely that the listeners relied on differences in spectral noise to discriminate the black and white speakers.

Assessment of the dynamics of vocal fold contact from the electroglottogram: data from normal male subjects.

Electroglottographic (EGG) and acoustic records from 10 normal men prolonging the vowel /a/ at 60-68 dB, 70-78 dB, and 80-88 dB SPL were obtained. "Contact quotient" (EGG duty cycle) was shown to vary directly with vocal SPL. The mean contact quotient was 0.57 (SD = 0.07) and varied on the order of 1% over the course of a given phonation. "Contact index", a metric of EGG symmetry, also tended to vary with SPL. Consistent with previous qualitative descriptions of EGG morphology in modal register voice, the contact index averaged -0.52 (SD = 0.08), indicating that the EGG "closing phase" represents about 24% of the entire "contact phase". Contact index was more variable than contact quotient on consecutive EGG waves, varying by about 10% during phonation. Subjects were also instructed to produce a slow crescendo. Sound pressure and EGG data indicated that both the slope of increasing EGG contact and EGG duty cycle were significantly related to the amplitude of the acoustic signal. These results suggest that quantitative electroglottography may provide powerful insights into the control and regulation of normal phonation and into the detection and characterization of pathology.

Vowel amplitude variation associated with the heart cycle.

Modulation of the acoustic amplitude of a sustained vowel across the cardiac (ECG) cycle was examined by signal-averaging techniques. Ten normal men prolonged [a] at a comfortable Fo maintained within three SPL ranges: 60-68, 70-78, and 80-88 dB. Peak-to-peak amplitude variation associated with the heart cycle averaged 8.5% (s.d. = 5.4) re: mean, varying from about 14% at low SPLs to approximately 3% at high SPLs. The amplitude modulation was estimated to account for 11.8% of the measured short-term amplitude perturbation (shimmer), ranging from about 5% to almost 22% for individual samples. The mean deterministic shimmer (Sd) was 0.036 dB (s.d. = 0.019), with a trend toward decreasing Sd with increasing SPL. Additionally, fundamental frequency variation across the heart cycle within these phonations was comparable to that observed by Orlikoff and Baken [J. Acoust. Soc. Am. 85, 888-893 (1989)], and was shown to be uninfluenced by vocal SPL, although deterministic jitter (Jd) did decrease with vocal intensity. The results are discussed in terms of how the phonovascular relationship may affect the reliability and interpretation of acoustic shimmer measures.

The relationship of age and cardiovascular health to certain acoustic characteristics of male voices.

The purpose of this investigation was to obtain information about the acoustic characteristics of men's voices as a function of age and cardiovascular health. Eighteen adult males, divided equally into groups of healthy young and elderly men and elderly men diagnosed with chronic atherosclerosis in the absence of other systemic complaints, prolonged the vowel /a/ at a comfortable pitch maintained within 70-78 dB SPL. Measures of mean fundamental frequency (F0), mean jitter and shimmer (both absolute and relative), and the standard deviation of F0, SPL, and peak-to-peak vocal amplitude were computed. Significant differences were found between the healthy young and healthy elderly subjects on measures of F0 and amplitude SD, percent jitter, and shimmer. Differences were generally magnified when the younger subjects were compared with the elderly atherosclerotic subjects. Although only percent jitter significantly differentiated between the two geriatric groups, the atherosclerotics' phonations were generally associated with greater short- and long-term variability (as well as intersubject variability) than the healthy elderly men. Unlike the younger subjects, the elderly (especially the elderly atherosclerotic) subjects' perturbation measures fell much closer to the upper limits established in the literature for normal voices, indicating that the elderly speaker may be more prone to vocal disruption in the face of pathology.

The effect of the heartbeat on vocal fundamental frequency perturbation.

Signal-averaging and autocorrelation analysis revealed that the cardiovascular system exerts a modest but consistent influence on vocal fundamental frequency (Fo), accounting for approximately 0.5% to 20% of the absolute Fo perturbation (jitter) measured during a sustained phonation. There was also a marked trend for this percentage to decrease with increasing vocal Fo. Estimated mean "deterministic jitter" (Jd) values of 3.7 microsec (SD = 3.2) and 0.9 microsec (SD = 0.5) were derived from 6 normal male and 6 normal female subjects, respectively, with an overall mean of 2.3 microsec (SD = 2.7). These values represent approximately 6.9% of the mean total jitter for men and 2.4% of the mean total jitter for women, or about 4.6% for all subjects. The results are discussed in terms of their significance regarding more reliable vocal jitter measurement.

Fundamental frequency modulation of the human voice by the heartbeat: preliminary results and possible mechanisms.

Signal-averaging techniques reveal that the vocal fundamental frequency (F0) of a sustained vowel is modulated over a period equal to that of the speaker's heart cycle. Average F0 deviation varies in an orderly way from about 0.5% to about 1.0% as F0 changes. Location of the peak deviation in the time frame of the heart cycle also changes systematically with vocal F0. Modulation of the vocal F0 is likely to be caused by pressure-related changes in the stiffness of the vascular bed of the vocal folds and by alterations of the geometry of the thyroarytenoid muscle produced by periodic vascular engorgement.

Changes in vocal fundamental frequency at the segmental level: control during voiced fricatives.

In addition to cycle-by-cycle (jitter) and long-term (intonation contour and declination) changes, vocal fundamental frequency (Fo) is known to vary during moments of production of individual phones. This study explored the relationship between intra-oral pressure and Fo during the production of the English voiced fricatives (v), (z), (o), and (3). Target words were embedded in a carrier phrase spoken with three different patterns of sentence stress. Fo changed at a mean rate of -3.59 Hz/cmH2O and -7.96 Hz/cmH2O in men and women, respectively. No significant difference was observed among the different fricatives nor among the several stress patterns. A significant sex effect, not observed in a prior related study, was eliminated by conversion of the Fo data to semitones. The observed magnitudes of the ratios of Fo change to pressure change are consistent with several earlier studies that explored the effect of passive transglottal pressure changes on Fo. The present findings imply that, although Fo regulation is involved in the generation of different intonation contours, the laryngeal system is not compensated to maintain Fo in the face of the transitory changes in vocal-tract aerodynamics that accompany voiced fricative production.