Britta Hammarberg

Vocal Fold Vibrations: High-Speed Imaging, Kymography, and Acoustic Analysis: A Preliminary Report †

Objectives To evaluate a new analysis system, High‐Speed Tool Box (H. Larsson, custom‐made program for image analysis, version 1.1, Department of Logopedics and Phoniatrics, Huddinge University Hospital, Huddinge, Sweden, 1998) for studying vocal fold vibrations using a high‐speed camera and to relate findings from these analyses to sound characteristics.

Aerodynamic and acoustic voice measurements of patients with vocal nodules: variation in baseline and changes across voice therapy.

An important clinical issue concerns the efficacy of current voice therapy approaches in treating voice disorders, such as vocal nodules. Much research focuses on finding reliable methods for documentation of treatment results. In this second treatment study of ten patients with vocal nodules, who participated in a behaviorally based voice therapy program, 11 aerodynamic (transglottal air pressure and glottal waveform) and acoustic (spl, f0, and spectrum slope) measures were used. Three pretherapy baseline assessments were carried out, followed by one assessment after each of five therapy phases. Measurements were made of two types of speech materials: Strings of repeated /pae/ syllables and sustained /ae/ phonations in two loudness conditions: comfortable loudness and loud voice. The data were normalized using z-scores, which were based on data from 22 normal subjects. The results showed that the aerodynamic measures reflected the presence of vocal pathology to a higher degree than did the acoustic spectral measures, and they should be useful in studies comparing nodule and normal voice production. Large individual session-to-session variation was found for all measures across pretherapy baseline recordings, which contributed to nonsignificant differences between baseline and therapy data.

Glottal closure, transglottal airflow, and voice quality in healthy middle-aged women

Seventeen healthy women, 45 to 61 years old, were examined using videofiberstroboscopy during phonation at three loudness levels. Two phoniatricians evaluated glottal closure using category and ratio scales. Transglottal airflow was studied by inverse filtering of the oral airflow signal recorded in a flow mask (Glottal Enterprises System) during the spoken phrase /ba:pa:pa:pa:p/ at three loudness levels. Subglottal pressure was estimated from the intraoral pressure during p occlusion. Running speech and the repeated /pa:/ syllables were perceptually evaluated by three speech pathologists regarding breathiness, hypo-, and hyperfunction, using continuous scales. Incomplete glottal closure was found in 35 of 46 phonations (76%). The degree of glottal closure increased significantly with raised loudness. Half of the women closed the glottis completely during loud phonation. Posterior glottal chink (PGC) was the most common gap configuration and was found in 28 of 46 phonations (61%). One third of the PGCs were in the cartilaginous glottis (PGCc) only. Two thirds extended into the membranous portion (PGCm); most of these occurred during soft phonation. Peak flow, peak-to-peak (AC) flow, and the maximum rate of change for the flow in the closing phase increased significantly with raised loudness. Minimum flow decreased significantly from normal to loud voice. Breathiness decreased with increased loudness. The results suggest that the incomplete closure patterns PGCc and PGCm during soft phonation ought primarily to be regarded as normal for Swedish women in this age group.

Voice Research and Clinical Needs

The purpose of this paper is to provide a review of recent advances in voice research with special focus on clinical aspects and on the speaking voice. First an update on histological findings concerning the multilayer structure and the biomechanics of the vocal folds is given. Other topics are vocal fold closure patterns, the development of the voice from childhood to senescence, and theoretical aspects of vocal function from an acoustic-aerodynamic point of view. Special emphasis is put on voice parameters, which can be assumed to be relevant to underlying physiology, and how they can be captured by different techniques.

Voice characteristics, effects of voice therapy, and long-term follow-up of contact granuloma patients

This study evaluates the laryngoscopic findings and voice characteristics of male contact granuloma patients before and after voice therapy and at a follow-up about 9 years later. Pre- and posttherapy recordings as well as follow-up recordings were made for 19 granuloma patients. Pretherapy revealed the most salient perceptual voice characteristics were low pitch, monotony, and a high degree of vocal fry and hyperfunction. Interjudge reliability for these traits was high. Immediately following therapy the healed patients (n = 10) had a decrease in hyperfunction, vocal fry, and monotony, while the unhealed patients (n = 9) had an increase in hyperfunction and vocal fry decreased only marginally. Monotony decreased significantly in this group. As regards the acoustic analyses, no significant differences were found in mean fundamental frequency (F0) or perturbation. At the follow-up assessment 4 patients had granuloma while 15 had normal laryngeal status. Perceptually their voice characteristics resembled those pretherapy independently of the laryngeal findings. The results suggest that reduced hyperfunction and decreased vocal fry may create better circumstances for the healing process at the posterior glottis.

A voice accumulator device: Evaluation based on studio and field recordings

A voice accumulator is a portable device for long-term measurements of voice use in natural conditions. A contact microphone attached to the front part of the neck registers vocal fold vibrations. The purposes of the present study were: 1) to evaluate the voice accumulators two measuring programs optimized for registration of fundamental frequency (F0) and phonation time, respectively; and 2) to test the voice accumulator for field recordings. Four healthy subjects were recorded in a sound-proof booth simultaneously with one contact microphone into a voice accumulator and one contact microphone into a computer. In terms of F0 and phonation time, the results showed that correlations between the voice accumulators two measuring programs and a signal-processing program were high ( r S 0.85) for all subjects but one. The inter-subject variability was large. A prerequisite for reliable vocal fold vibration detection by the voice accumulator was a careful placement and a firm attachment of the contact microphone on the neck. Four subjects were recorded with the voice accumulator during a working day. It was concluded that the voice accumulator is an overall good instrument for measurements of F0 and phonation time, and thus is useful for both clinical work and research.

Methods to study pre-school teachers' voice at work: simultaneous recordings with a voice accumulator and a DAT recorder.

Long-term recordings with reliable methods are desirable for objective documentation of voice use during natural conditions. The purpose of this study was to evaluate a voice accumulator (VAC) with a digital audiotape (DAT) recorder as a reference. The VAC is based on a microprocessor that accumulates information about fundamental frequency (F0) and phonation time. A contact microphone attached to the front of the neck registers vocal fold vibrations. The DAT recorder was connected to two microphones for airborne signals placed at equal distance from the mouth close to the subjects ears. The computer program Aura was used to separate the subjects voicefrom the background noise. The Soundswell program was used for F0 and phonation time analysis. Two sets were performed: 1) One female speech-language pathologist was recorded with the two devices simultaneously in a sound-proof booth. She read a standard text with different voice qualities and sustained vowels with increasing F0 and intensity separately. The results showed good agreement between the two methods with respect to F0 and phonation time. However, the VAC failed to register high frequencies above around 440 Hz as well as low intensities. 2) Three female pre-school teachers were recorded with the two devices simultaneously during a working day. Results showed high correlations between the two methods in terms of long-term measurements of F0 and phonation time for two subjects. For one subject with subcutaneous soft tissue on the neck, the registration with the contact microphone was not reliable. It was concluded that the VAC has the potential for assessment of occupational voice disorders if certain limitations of the method are considered.

Voice handicap and health-related quality of life in laryngectomees: assessments with the use of VHI and EORTC questionnaires.

Aims: To investigate the Voice Handicap Index (VHI), the health-related quality of life (HRQL), and the correlations between VHI and HRQL in laryngectomees. Methods: Forty-three laryngectomized persons participated (mean age 68;6 years, time since laryngectomy between 0;6 and 12 years). Evaluation of voice handicap was done with the VHI. HRQL was evaluated with questionnaires from the European Organization for Research and Treatment of Cancer, EORTC QLQ-C30 and EORTC QLQ-H&N35. Results: VHI for the whole group demonstrated a moderate voice handicap, with a mean score of 48/120. The functional scales of EORTC QLQ-C30 resulted in scores on the same level as the normal population with the exception of a lower global quality of life scale (Global QOL). EORTC QLQ-H&N35 revealed problems with smell and taste, speech, coughing, xerostomia, and sexuality. VHI correlated significantly with the Global QOL, the functional scales, dyspnea, pain, nausea and financial difficulties (EORTC QLQ-C30). Significant correlations were also found between VHI and speech problems, social contact, pain from the head and neck area, sense problems, sexuality and social eating (EORTC QLQ-H&N35). Conclusion: The EORTC questionnaires in combination with the VHI questionnaire seem to capture most of the problems following laryngectomy, including voice problems.

The correlogram: A visual display of periodicity

Fundamental frequency (F0) extraction is often used in voice quality analysis. In pathological voices with a high degree of instability in F0, it is common for F0 extraction algorithms to fail. In such cases, the faulty F0 values might spoil the possibilities for further data analysis. This paper presents the correlogram, a new method of displaying periodicity. The correlogram is based on the waveform-matching techniques often used in F0 extraction programs, but with no mechanism to select an actual F0 value. Instead, several candidates for F0 are shown as dark bands. The result is presented as a 3D plot with time on the x axis, correlation delay inverted to frequency on the y axis, and correlation on the z axis. The z axis is represented in a gray scale as in a spectrogram. Delays corresponding to integer multiples of the period time will receive high correlation, thus resulting in candidates at F0, F0/2, F0/3, etc. While the correlogram adds little to F0 analysis of normal voices, it is useful for analysis of pathological voices since it illustrates the full complexity of the periodicity in the voice signal. Also, in combination with manual tracing, the correlogram can be used for semimanual F0 extraction. If so, F0 extraction can be performed on many voices that cause problems for conventional F0 extractors. To demonstrate the properties of the method it is applied to synthetic and natural voices, among them six pathological voices, which are characterized by roughness, vocal fry, gratings/scrape, hypofunctional breathiness and voice breaks, or combinations of these.

The pharyngoesophageal segment in laryngectomees—videoradiographic, acoustic, and voice quality perceptual data

This study aimed to relate the results of physiological measurements of the pharyngoesophageal (PE) segment in subjects using tracheoesophageal (TE) or esophageal (E) speech with perceptual assessment of the speakers’ voice quality and acoustic measurements of the voice function. It further aimed to investigate possible differences in appearance and placement of the voice source between TE and E speakers. Nine subjects who had undergone a laryngectomy (five TE speakers and four E speakers) participated in the study. They were videoradiographically examined during phonation and silence. Measurements were made of size and placement of the PE segment, the distance between the PE segment and the anterior wall, and the distance between the posterior and anterior esophageal walls beneath the segment. Five trained listeners perceptually assessed the subjects’ voice quality, and acoustical analyses of fundamental frequency and sound pressure level were made. The physiological measurements of the nine subjects’ individual PE segments varied in terms of appearance and placement during both phonation and silence, but all of the subjects showed a good closure at the PE segment level during phonation. Statistically significant results were found between all of the physiological measurements of the PE segment. Significant results were also found between the acoustical and perceptual assessments of the subjects’ voices. No relations were found between the physiological measurements and the acoustic and perceptual results. The conclusion of this study was that there were no specified differences in the PE segment between TE speakers and E speakers, but that there were large individual differences within each speaker group.