Reliable jitter and shimmer measurements in voice clinics: the relevance of vowel, gender, vocal intensity, and fundamental frequency effects in a typical clinical task.

The aims of this study were to examine vowel and gender effects on jitter and shimmer in a typical clinical voice task while correcting for the confounding effects of voice sound pressure level (SPL) and fundamental frequency (F(0)). Furthermore the relative effect sizes of vowel, gender, voice SPL, and F(0) were assessed, and recommendations for clinical measurements were derived. With this cross-sectional single cohort study, 57 healthy adults (28 women, 29 men) aged 20-40 years were investigated. Three phonations of /a/, /o/, and /i/ at "normal" voice loudness were analyzed using Praat (software). The effects of vowel, gender, voice SPL, and F(0) on jitter and shimmer were assessed using descriptive and inferential (analysis of covariance) statistics. The effect sizes were determined with the eta-squared statistic. Vowels, gender, voice SPL, and F(0), each had significant effects either on jitter or on shimmer, or both. Voice SPL was the most important factor, whereas vowel, gender, and F(0) effects were comparatively small. Because men had systematically higher voice SPL, the gender effects on jitter and shimmer were smaller when correcting for SPL and F(0). Surprisingly, in clinical assessments, voice SPL has the single biggest impact on jitter and shimmer. Vowel and gender effects were clinically important, whereas fundamental frequency had a relatively small influence. Phonations at a predefined voice SPL (80 dB minimum) and vowel (/a/) would enhance measurement reliability. Furthermore, gender-specific thresholds applying these guidelines should be established. However, the efficiency of these measures should be verified and tested with patients.

Hydroxyapatite versus titanium implant: Comparison of the functional outcome after vocal fold medialization in unilateral recurrent nerve paralysis.

BACKGROUND: Results of medialization thyroplasty for treatment of unilateral vocal fold paralysis are often unsatisfactory. This study compares glottal closure and voice quality after use of 2 different medialization implant types: VoCoM and TVFMI. METHODS: In all, 26 patients with unilateral vocal fold paralysis following thoracic surgery underwent medialization thyroplasty. In 11 patients (group I), a hydroxyapatite implant (VoCoM) was used. In 15 patients (group II), a titanium implant (TVFMI) was used. Preoperative and postoperative glottal closure and voice function were assessed with videostroboscopy, perceptual and objective voice measures, and the Voice Dysfunction Index (VDI). RESULTS: Group II showed a higher rate of complete glottal closure and greater improvement in perceived hoarseness, maximal phonation time, and maximal voice intensity than those in group I. CONCLUSIONS: With the individually adjustable titanium implant, better glottal closure and better functional outcome (phonation time and voice quality) were achieved.

Voice loudness and gender effects on jitter and shimmer in healthy adults.

PURPOSE: The aim of this study was to investigate voice loudness and gender effects on jitter and shimmer in healthy young adults because previous descriptions have been inconsistent. METHOD: Fifty-seven healthy adults (28 women, 29 men) aged 20-40 years were included in this cross-sectional single-cohort study. Three phonations of /a/ at soft, medium, and loud individual loudness were recorded and analyzed using PRAAT software (P. Boersma & D. Weeninkk, 2006). Voice loudness and gender effects on measured sound pressure level, fundamental frequency, jitter, and shimmer were assessed through the use of descriptive and inferential (analysis of variance) statistics. RESULTS: Jitter and shimmer significantly increased with decreasing voice loudness, especially in phonations below 75 dB and 80 dB. In soft and medium phonation, men were generally louder and showed significantly less shimmer. However, men had higher jitter measures when phonating softly. Gender differences in jitter and shimmer at medium loudness may be mainly linked to different habitual voice loudness levels. CONCLUSION: This pragmatic study shows significant voice loudness and gender effects on perturbation. In clinical assessment, requesting phonations above 80 dB at comparable loudness between genders would enhance measurement reliability. However, voice loudness and gender effects in other age groups, in disordered voices, or when a minimal loudness is requested should be further investigated.

Changes in self-perceived role identity modulate pain perception.

Pain is an experience including physiological and psychological factors. We assume that emotions may be elicited and increased through self-perceived role identity and that change of role identity alters quality and intensity of pain perception. We used role-play strategies to assess whether pain can be better tolerated whenever, in an unavoidable and unpleasant context, role identity confers pain a meaningful and thus suitable character. We induced antithetic roles in 21 actors who received heat stimuli on their arms before and after role-play conditions. Pain tolerance, skin conductance and voice signals were measured. Pain tolerance increased for heroes/heroines and decreased for faint-hearts. Men showed higher pain tolerance. Heroes/heroines evaluated heat stimuli as more intense. Faint-hearts found pain stimuli more affectively loaded at lower temperatures. Women showed higher pain ratings. Hence, self-perception influences pain perception. Role-play strategies may be of value for new pain management strategies.

Functional outcome of vocal fold medialization thyroplasty with a hydroxyapatite implant.

OBJECTIVES: Unilateral vocal fold paralysis can cause a persistent incomplete glottal closure during phonation, resulting in impaired voice function. The aim of this study was to evaluate functional results of medialization thyroplasty using a hydroxyapatite implant (VoCoM). STUDY DESIGN: Prospective observational cohort study. METHODS: Between 1999 and 2003, a total of 26 patients (19 men, 7 women) undergoing medialization thyroplasty using a hydroxyapatite implant because of unilateral vocal fold paralysis were enrolled in the study. To evaluate voice function, the following parameters were measured preoperatively and postoperatively: mean fundamental frequency, mean sound pressure level, frequency and amplitude range (voice range profile), and maximum phonation time. A perceptual assessment of hoarseness was conducted using the Roughness, Breathiness, Hoarseness scale. Furthermore, the magnitude of voice related impairment of the patient's communication skills was rated on a 7-point scale. A combined parameter called the Voice Dysfunction Index (VDI) was used to rate vocal performance. RESULTS: All patients showed a statistically significant improvement in the VDI, in perceptual voice analysis, in maximum phonation time, and in the dynamic range of voice. One patient experienced a postoperative wound hemorrhage as a minor complication. No further complications or implant extrusions were observed. CONCLUSIONS: Medialization thyroplasty using a hydroxyapatite implant is a secure and efficient phonosurgical procedure. Voice quality and patient satisfaction improve significantly after treatment.