Aerodynamic characteristics of laryngectomees breathing quietly and speaking with the electrolarynx

Improving the Quality and Intelligibility of Electrolaryngeal Speech during Mobile Communication with Landline Analogous Bandpass Filtering

The normal functioning of the larynx or voicebox gives humans the ability to converse with others effortlessly. However, if the larynx is permanently removed due to injury or illness, speech cannot be produced. The electrolarynx, a noninvasive device used to produce speech for such persons, has a motor-induced hum which hinders telephone-based communication among electrolaryngeal speakers. This adversely affects the morale of electrolarynx users, leading to abandonment of technology, psychological issues and decreased quality of life. This paper examines a technique based on bandpass filtering of electrolaryngeal speech which has the potential of increasing the quality and intelligibility of speech produced by means of an electrolarynx. Finite impulse response and infinite impulse response filtering with bandpass frequencies analogous to telephone landline and wideband filtering were investigated. Objective testing and subjective testing of quality and intelligibility of electrolaryngeal speech have been performed in each phase of the work. Statistical analysis based on one-way analysis of variance (ANOVA) has been conducted after each round of subjective testing. Results indicate that the quality as well as intelligibility of electrolaryngeal speech can be improved with the help of bandpass filtering.

The electrolarynx: voice restoration after total laryngectomy

The ability to speak and communicate with one’s voice is a unique human characteristic and is fundamental to many activities of daily living, such as talking on the phone and speaking to loved ones. When the larynx is removed during a total laryngectomy (TL), loss of voice can lead to a devastating decrease in a patient’s quality of life, and precipitate significant frustration over their inability to communicate with others effectively. Over the past 50 years there have been many advances in techniques of voice restoration after TL. Currently, there are three main methods of voice restoration: the electrolarynx, esophageal speech, and tracheoesophageal speech through a tracheoesophageal puncture (TEP) with voice prosthesis. Although TEP voice is the current gold standard for vocal rehabilitation, a significant minority of patients cannot use or obtain TEP speech for various reasons. As such, the electrolarynx is a viable and useful alternative for these patients. This article will focus on voice restoration using an electrolarynx with the following objectives: 1) To provide an understanding of the importance of voice restoration after total laryngectomy. 2) To discuss how the electrolarynx may be used to restore voice following total laryngectomy. 3) To outline some of the current electrolarynx devices available, including their mechanism of action and limitations. 4) To compare pros and cons of electrolaryngeal speech to TEP and esophageal speech.

Development of a time-dependent numerical model for the assessment of non-stationary pharyngoesophageal tissue vibrations after total laryngectomy

Laryngeal cancer due to, e.g., extensive smoking and/or alcohol consumption can necessitate the excision of the entire larynx. After such a total laryngectomy, the voice generating structures are lost and with that the quality of life of the concerning patients is drastically reduced. However, the vibrations of the remaining tissue in the so called pharyngoesophageal (PE) segment can be applied as alternative sound generator. Tissue, scar, and geometric aspects of the PE-segment determine the postoperative substitute voice characteristic, being highly important for the future live of the patient. So far, PE-dynamics are simulated by a biomechanical model which is restricted to stationary vibrations, i.e., variations in pitch and amplitude cannot be handled. In order to investigate the dynamical range of PE-vibrations, knowledge about the temporal processes during substitute voice production is of crucial interest. Thus, time-dependent model parameters are suggested in order to quantify non-stationary PE-vibrations and drawing conclusions on the temporal characteristics of tissue stiffness, oscillating mass, pressure, and geometric distributions within the PE-segment. To adapt the numerical model to the PE-vibrations, an automatic, block-based optimization procedure is applied, comprising a combined global and local optimization approach. The suggested optimization procedure is validated with 75 synthetic data sets, simulating non-stationary oscillations of differently shaped PE-segments. The application to four high-speed recordings is shown and discussed. The correlation between model and PE-dynamics is ≥ 97%.

Design and evaluation of an electrolarynx with tonal control function for Mandarin

OBJECTIVE

To improve the speech quality of laryngectomized speakers of Mandarin, we designed an electrolarynx with tonal control function (tone-EL) by using the movement of a trackball. The performance of the tone-EL in producing Mandarin was evaluated.

METHODS

The performance of tone-EL was evaluated via a listening experiment. The perceptual accuracies of monosyllabic words, different categories of phrases with different cues were measured and compared with that produced with a conventional EL. The acceptability of sentences was also measured.

RESULTS

The perceptual accuracies of monosyllabic words and tones associated with the words produced with the tone-EL were significantly higher than those of monotonic EL speech. The perceptual accuracy of phrases was significantly higher than in monotonic EL speech when no categorical cue for listeners was provided, whereas they were at a close level when categorical information of the phrases was provided in advance. The acceptability of sentences was higher than that of monotonic EL speech.

CONCLUSION

Using the tone-EL can produce Mandarin tones effectively and the quality of rehabilitated Mandarin is better than using a conventional-EL. To balance speech intelligibility and ease of use, a strategy -producing tonal speech when few informative cues are available to listeners is preferred.

In Vitro Evaluation of the iValve: A Novel Hands-Free Speech Valve

Objectives:

We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure drops. This method makes long sentences or pauses difficult. The novel iValve is designed to allow almost natural speech, with mid-sentence pausing and whispering.

Methods:

The inhalation closing flows and exhalation opening pressures of 6 iValve prototype versions at different settings were compared with physiological values. The airflow resistance at inhalation was compared to physiological values and to commercial valve values.

Results:

The iValve prototypes showed flow and pressure ranges in concordance with the physiological values in the literature. The airflow resistance in the breathing mode was within the physiological airflow resistance range, yet above the values from the two commercial valves. The resistance in the speaking mode was above the physiological airflow resistance range.

Conclusions:

In vitro tests show that the iValve versions can be selected and adjusted to operate within the physiological range. The airflow resistance in the breathing mode is good. In speaking mode, inhalation should, and can, be decreased. The iValve should offer the patient a more intuitively useable alternative with more dynamic speech. Its low cost allows disposability and wider use.

Speech breathing in speakers who use an electrolarynx

Speakers who use an electrolarynx following a total laryngectomy no longer require pulmonary support for speech. Subsequently, chest wall movements may be affected; however, chest wall movements in these speakers are not well defined. The purpose of this investigation was to evaluate speech breathing in speakers who use an electrolarynx during speech and reading tasks. Six speakers who use an electrolarynx underwent an evaluation of chest wall kinematics (e.g., chest wall movements, temporal characteristics of chest wall movement), lung volumes, temporal measures of speech, and the interaction of linguistic influences on ventilation. Results of the present study were compared to previous reports in speakers who use an electrolarynx, as well as to previous reports in typical speakers. There were no significant differences in lung volumes used and the general movement of the chest wall by task; however, there were differences of note in the temporal aspects of chest wall configuration when compared to previous reports in both typical speakers and speakers who use an electrolarynx. These differences were related to timing and posturing of the chest wall. The lack of differences in lung volumes and chest wall movements by task indicates that neither reading nor spontaneous speech exerts a greater influence on speech breathing; however, the temporal and posturing results suggest the possibility of a decoupling of the respiratory system from speech following a total laryngectomy and subsequent alaryngeal speech rehabilitation.

LEARNING OUTCOMES

The reader will be able to understand and describe: (1) The primary differences in speech breathing across alaryngeal speech options; (2) how speech breathing specifically differs (i.e., lung volumes and chest wall movements) in speakers who use an electrolarynx; (3) How the coupling of speech and respiration is altered when pulmonary air is no longer used for speech.

Long-term average spectral characteristics of Cantonese alaryngeal speech

OBJECTIVE

In Hong Kong, esophageal (SE), tracheoesophageal (TE), electrolaryngeal (EL), and pneumatic artificial laryngeal (PA) speech are commonly used by laryngectomees as a means to regain verbal communication after total laryngectomy. While SE and TE speech has been studied to some extent, little is known regarding the EL and PA sound quality. The present study examined the sound quality associated with SE, TE, EL, and PA speech, and compared with that associated with laryngeal (NL) speech by using long-term average speech spectra (LTAS).

METHODS

Continuous speech samples of reading a 136-word passage were obtained from NL, SE, TE, EL, and PA speakers of Cantonese. The alaryngeal speakers were all superior speakers selected from the New Voice Club of Hong Kong, which is a self-help organization for the laryngectomees in Hong Kong. TE speakers were fitted with Provox valve, and EL speakers used Servox-type electrolarynx. Speech samples were digitized at 20kHz and 16bits/sample by using Praat, based on which LTAS contours were developed. First spectral peak (FSP), mean spectral energy (MSE), and spectral tilt (ST) derived from the LTAS contours associated with different speaker groups were compared.

RESULTS

Data revealed all speakers generally exhibited similar LTA contours. However, PA speakers exhibited the lowest average FSP value and the greatest average MSE value. NL phonation was associated with a significantly greater ST value than alaryngeal speech of Cantonese.

CONCLUSION

The differences in FSP, MSE, and ST values in different speaker groups may be related to the different sound sources being used by the laryngectomees, and the difference in the way the sound source is coupled with the vocal tract system.

Post-laryngectomy speech respiration patterns

OBJECTIVES

The goal of this study was to determine whether speech breathing changes over time in laryngectomy patients who use an electrolarynx, to explore the potential of using respiratory signals to control an artificial voice source.

METHODS

Respiratory patterns during serial speech tasks (counting, days of the week) with an electrolarynx were prospectively studied by inductance plethysmography in 6 individuals across their first 1 to 2 years after total laryngectomy, as well as in an additional 8 individuals who had had a laryngectomy at least 1 year earlier.

RESULTS

In contrast to normal speech that is only produced during exhalation, all individuals were found to engage in inhalation during speech production, and those studied longitudinally displayed increased occurrences of inhalation during speech production with time after laryngectomy. These trends appear to be stronger for individuals who used an electrolarynx as their primary means of oral communication rather than tracheoesophageal speech, possibly because of continued dependence on respiratory support for the production of tracheoesophageal speech.

CONCLUSIONS

Our results indicate that there are post-laryngectomy changes in the speech breathing behaviors of electrolarynx users. This has implications for designing improved electrolarynx communication systems, which could use signals derived from respiratory function as one of many potential physiologically based sources for more natural control of electrolarynx speech.

Diurnal cortisol levels and cortisol response in youths with obsessive-compulsive disorder

BACKGROUND/AIMS

Recent results indicate a role of the hypothalamic-pituitary-adrenal (HPA) axis in the pathophysiology of obsessive-compulsive disorder (OCD). Although childhood onset is common, the HPA axis has scarcely been studied in young OCD subjects. Therefore, the present study aimed at examining basal and response levels of salivary cortisol in a sample of young OCD subjects.

METHODS

Twenty-three children and adolescents with DSM-IV OCD were compared to a reference group of school children (n = 240-336). The basal cortisol rhythm was measured through saliva samples 3 times/day. The cortisol response to a psychological stressor (exposure therapy in the OCD group and a fire alarm in the reference group) was also examined.

RESULTS

Compared to the reference group, OCD subjects displayed higher early-morning cortisol values (p = 0.005) with no difference between the late-morning and evening values. The cortisol levels in the OCD group diminished in response to the psychological stressor, compared to a positive response in the reference group (p < 0.001). No relation was found between cortisol and clinical parameters.

CONCLUSION

These results support the idea that HPA hyperactivity, commonly found in adult OCD patients, is also present at an earlier stage of development, with specificity for the early-morning peak.

Electrolarynx in voice rehabilitation

OBJECTIVE

Patients of laryngeal cancer who have undergone the surgical removal of the entire larynx suffer the loss of phonation. Electrolarynx (EL) speech is the most commonly adopted alaryngeal phonation. However, EL speech is notorious of the sound quality being monotonic and robotic with the lack of pitch control and the presence of the radiated noise. This paper provides a review of modalities in EL speech as well as introducing the technologies to control the pitch and reduce the noise of the device.

METHODS

Improvements of EL speech quality have been divided into two parts: improving the sound quality of EL device by applying different enhancement algorithms to reduce the radiated and the additive noise, and implementing pitch-control function to the EL with advanced technology.

RESULTS

Adaptive filtering and the subtractive-type algorithms have shown to be able to reduce the noise level associated with EL speech. And more mature technologies are showing promise to the making of a hand-free EL system producing more accurate and synchronized pitch and voice onset control.

CONCLUSION

The advent of micro-technology and human-machine integration promisingly improves EL speech quality and more efficient algorithms enhance EL sound quality. Such improvements apparently improve the intelligibility of EL speech, and thus better quality of life of the EL speakers.