Resonance Tube Phonation in Water-the Effect of Tube Diameter and Water Depth on Back Pressure and Bubble Characteristics at Different Airflows.

OBJECTIVES: Resonance tube phonation with tube end in water is a voice therapy method in which the patient phonates through a glass tube, keeping the free end of the tube submerged in water, creating bubbles. The purpose of this experimental study was to determine flow-pressure relationship, flow thresholds between bubble types, and bubble frequency as a function of flow and back volume. METHODS: A flow-driven vocal tract simulator was used for recording the back pressure produced by resonance tubes with inner diameters of 8 and 9 mm submerged at water depths of 0-7 cm. Visual inspection of bubble types through video recording was also performed. RESULTS: The static back pressure was largely determined by the water depth. The narrower tube provided a slightly higher back pressure for a given flow and depth. The amplitude of the pressure oscillations increased with flow and depth. Depending on flow, the bubbles were emitted from the tube in three distinct types with increasing flow: one by one, pairwise, and in a chaotic manner. The bubble frequency was slightly higher for the narrower tube. An increase in back volume led to a decrease in bubble frequency. CONCLUSIONS: This study provides data on the physical properties of resonance tube phonation with the tube end in water. This information will be useful in future research when looking into the possible effects of this type of voice training.

The Flow and Pressure Relationships in Different Tubes Commonly Used for Semi-occluded Vocal Tract Exercises.

This experimental study investigated the back pressure (P(back)) versus flow (U) relationship for 10 different tubes commonly used for semi-occluded vocal tract exercises, that is, eight straws of different lengths and diameters, a resonance tube, and a silicone tube similar to a Lax Vox tube. All tubes were assessed with the free end in air. The resonance tube and silicone tube were further assessed with the free end under water at the depths from 1 to 7 cm in steps of 1 cm. The results showed that relative changes in the diameter of straws affect P(back) considerably more compared with the same amount of relative change in length. Additionally, once tubes are submerged into water, P(back) needs to overcome the pressure generated by the water depth before flow can start. Under this condition, only a small increase in P(back) was observed as the flow was increased. Therefore, the wider tubes submerged into water produced an almost constant P(back) determined by the water depth, whereas the thinner straws in air produced relatively large changes to P(back) as flow was changed. These differences may be taken advantage of when customizing exercises for different users and diagnoses and optimizing the therapy outcome.

Resonance tube phonation in water: High-speed imaging, electroglottographic and oral pressure observations of vocal fold vibrations--a pilot study.

Phonation into glass tubes ('resonance tubes'), keeping the free end of the tube in water, has been a frequently used voice therapy method in Finland and more recently also in other countries. The purpose of this exploratory study was to investigate what effects tube phonation with and without water has on the larynx. Two participants were included in the study. The methods used were high-speed imaging, electroglottographic observations of vocal fold vibrations, and measurements of oral pressure during tube phonation. Results showed that the fluctuation in the back pressure during tube phonation in water altered the vocal fold vibrations. In the high-speed imaging, effects were found in the open quotient and amplitude variation of the glottal opening. The open quotient increased with increasing water depth (from 2 cm to 6 cm). A modulation effect by the water bubbles on the vocal fold vibrations was seen both in the high-speed glottal area tracings and in the electroglottography signal. A second experiment revealed that the increased average oral pressure was largely determined by the water depth. The increased open quotient can possibly be explained by an increased abduction of the vocal folds and/or a reduced transglottal pressure. The back pressure of the bubbles also modulates glottal vibrations with a possible 'massage' effect on the vocal folds. This effect and the well-defined average pressure increase due to the known water depth are different from those of other methods using a semi-occluded vocal tract.

Speaking fundamental frequency and phonation time during work and leisure time in vocally healthy preschool teachers measured with a voice accumulator.

OBJECTIVE: More knowledge is needed about preschool teachers' voice use to identify voice behaviours related to work demands that increase the risk for vocal dysfunction. The purpose of this study was to: (1) determine if speaking fundamental frequency (F0) and phonation time differ between work and leisure time and (2) describe variation in F0 and phonation time across the workday in preschool teachers with healthy voices. METHODS: A portable voice accumulator was used to collect data on F0 and phonation time. Twelve vocally healthy female preschool teachers participated in recordings during both work and leisure time for 2 successive days. Their mean age was 35 years (range 21-53 years). RESULTS: Mean F0 was high during the working day (266 Hz) and decreased significantly after work (p < 0.0001). F0 was high also during leisure time (246 Hz) as compared to reference F0 values for Swedish females based on laboratory recordings. Phonation time at work varied widely among the participants, with an average of 12.0%, and decreased significantly to 5.5% during leisure time (p < 0.0001). Most participants had few opportunities for voice rest during work. CONCLUSION: Swedish preschool teachers use high levels of F0 and phonation time during work compared to leisure time indicating high vocal load caused by work. To clarify the role of daily voice use in the causation of vocal dysfunction in this profession, recordings over several days are needed. In addition to F0 and phonation time, recordings of voice sound pressure level and background noise level seem important.

Speech and voice after laryngectomy: perceptual and acoustical analyses of tracheoesophageal speech related to voice handicap index.

OBJECTIVE: To perform perceptual and acoustical analyses of tracheoesophageal (TE) speech and relate these analyses to self-reported voice handicap. METHODS: Recordings of 35 TE speakers were perceptually assessed by 5 speech-language pathologists. Acoustical analyses were made of voice aspects and temporal speech aspects. Self-assessments of voice were made with the Voice Handicap Index (VHI). RESULTS: Perceptual assessment of TE speech showed significant correlations between overall degree of deviation and low speaking rate, deviant articulation, monotonous intonation, roughness and low pitch. The overall degree of deviation correlated significantly with acoustical measurements of speaking rate, articulation rate, and phrase length. Significant correlations were also found between assessed pitch and measured fundamental frequency, between assessed speaking rate and measured number of words per minute, and between assessed phrase length and measured number of syllables per breath. Self-assessments of VHI were significantly correlated with voice intensity and temporal speech aspects such as total reading time, phrase length, and percent pause time. No significant correlations were found between perceptual assessment and VHI degree. CONCLUSION: The listeners' ratings of overall degree of deviation in TE speech showed relations to both voice quality and temporal aspects in speech. The TE speakers' voice handicap degree were mainly related to changes in temporal aspects of speech.

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 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.

Perceptual and acoustic analysis of speech in individuals with spinocerebellar ataxia (SCA).

With current progress in genetic research, autosomal, dominant, hereditary, neurodegenerative diseases, affecting the cerebellum and cerebellar connections, are increasingly diagnosed as spinocerebellar ataxias (SCA). In the present study speech samples from 21 subjects with spinocerebellar ataxia (SCA), and 21 matched control subjects were analyzed using perceptual and acoustic methodology. Dysarthria assessment showed that subjects had mild or mild-moderate dysarthria. Perceptual analysis indicated that equalized stress, imprecise consonants, vocal instability, monotony and reduced speech rate were the speech parameters that yielded the highest mean perceptual ratings. A factor analysis of perceptual speech parameters revealed two main factors: Factor 1 was associated with articulatory timing and Factor 2 with vocal quality. Acoustic analysis revealed significantly reduced speech rate during text reading, reduced alternating and sequential motion rates (AMR/SMR), significantly longer and more variable syllable and pause durations, and significantly higher vocal instability for subjects with SCA compared to control subjects.

Voice problems as side effects of inhaled corticosteroids in asthma patients--a prevalence study.

Voice disturbances in asthma patients may be caused by inhaled corticosteroids. In order to study the prevalence of such voice disturbances, a questionnaire was delivered to asthma patients at three asthma and allergy departments in Stockholm. The questionnaire consisted of 25 questions concerning the asthma disease symptoms, medication, voice function, and voice disturbances. A total of 350 questionnaires were delivered. Response frequency was 80%. There was a significant positive correlation between inhalation of cortison and voice disturbances. Most of the patients complained about hoarseness, followed by throat clearing, a lump in the throat, loss of voice, and less frequently, throat pain. There were no significantly differences between men and women. Elderly had more voice problems than young persons. Patients with voice-demanding professions had more problems than patients who used their voice to a lesser extent during the working day. There was a significant positive correlation between high cortison doses and voice problems as well as between voice problems and acid regurgitation.

High-speed imaging of the voicing source in laryngectomees during production of voiced-voiceless distinctions for stop consonants.

This study presents results from high-speed imaging recordings of the voice source, that is the pharyngo-esophageal segment, in four laryngectomized men. The subjects were asked to produce VCV-syllables with voiced and voiceless stop consonants during simultaneous high-speed imaging recordings and audio recordings. A general and detailed visuo-perceptual analysis of the shape and vibratory pattern in the pharyngo-esophageal (PE-) segment was made, as well as acoustical measurements of voice onset time (VOT) and closure duration for each syllable. The syllables were also audio-perceptually evaluated by five expert listeners. Results show that the subjects had a high overall intelligibility as judged by the listeners. All four subjects were able to make opening gestures in the PE-segment while producing voiceless stop consonants. In cases where misperceptions were predominant, the acoustical analysis with spectrograms and the detailed analysis of the vibration in the PE-segment gave information about probable causes of the mishearings.

Ventricular fold vibration in voice production: a high-speed imaging study with kymographic, acoustic and perceptual analyses of a voice patient and a vocally healthy subject.

Co-vibrations of the ventricular folds are a common finding in the clinical setting. It is not always obvious how much of the perceived voice change can be attributed to the presence of such vibrations. The aim of the present study was to describe laryngeal vibrations as observed by high-speed imaging in cases where ventricular fold vibrations had been observed. The findings at kymographic display of the recordings were correlated to perceptual measures and spectrographic observations. Two subjects, a 65-year-old man with chronic laryngitis and one vocally healthy man, were examined during pressed and breathy sustained phonation. Perceived roughness in the voice quality correlated to irregularities in true vocal fold vibrations as well as to irregular ventricular fold vibrations with large amplitude combined with sufficient closure. In none of the recorded sections did ventricular fold vibrations occur without simultaneous true vocal fold vibrations. Regular vibrations of the ventricular folds of the same frequency as those of the true vocal folds and with a reciprocal pattern did not contribute to any roughness in the perceived voice.

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.

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.

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 subject's ears. The computer program Aura was used to separate the subject's voice from the background noise. The Soundswell program was used for F0 and phonation time analysis. Two tests 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 potential for assessment of occupational voice disorders if certain limitations of the method are considered.

Vocal behavior and vocal loading factors for preschool teachers at work studied with binaural DAT recordings.

Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices.