Application of spectral subtraction method on enhancement of electrolarynx speech

Using visual feedback to enhance intonation control with a variable pitch electrolarynx

This study evaluated the effectiveness of using visual feedback to facilitate pitch control by a speaker using a pressure sensitive onset controlled electrolarynx (EL). This proof-of-concept study was conducted with one healthy adult. The participant-speaker was provided with computer generated visual feedback over five sessions within a consecutive period of three weeks. Changes in force control accuracy were gathered and analyzed. An improvement in finger (thumb) force control accuracy from the first to the last training session was documented. The results of this study provide data toward the development of a clinical training protocol for the use of a pressure sensitive onset controlled EL by laryngectomized speakers. Further, these results highlight the importance of developing a relevant multimodality training protocol for the improvement of postlaryngectomy EL speech production.

Mandarin Electrolaryngeal Speech Recognition Based on WaveNet-CTC

Purpose The application of Chinese Mandarin electrolaryngeal (EL) speech for laryngectomees has been limited by its drawbacks such as single fundamental frequency, mechanical sound, and large radiation noise. To improve the intelligibility of Chinese Mandarin EL speech, a new perspective using the automatic speech recognition (ASR) system was proposed, which can convert EL speech into healthy speech, if combined with text-to-speech. Method An ASR system was designed to recognize EL speech based on a deep learning model WaveNet and the connectionist temporal classification (WaveNet-CTC). This system mainly consists of 3 parts: the acoustic model, the language model, and the decoding model. The acoustic features are extracted during speech preprocessing, and 3,230 utterances of EL speech mixed with 10,000 utterances of healthy speech are used to train the ASR system. Comparative experiment was designed to evaluate the performance of the proposed method. Results The results show that the proposed ASR system has higher stability and generalizability compared with the traditional methods, manifesting superiority in terms of Chinese characters, Chinese words, short sentences, and long sentences. Phoneme confusion occurs more easily in the stop and affricate of EL speech than the healthy speech. However, the highest accuracy of the ASR could reach 83.24% when 3,230 utterances of EL speech were used to train the ASR system. Conclusions This study indicates that EL speech could be recognized effectively by the ASR based on WaveNet-CTC. This proposed method has a higher generalization performance and better stability than the traditional methods. A higher accuracy of the ASR system based on WaveNet-CTC can be obtained, which means that EL speech can be converted into healthy speech. Supplemental Material https://doi.org/10.23641/asha.8250830.

Design and Evaluation of a Mechanically Driven Artificial Speech Device

This paper presents the design of a mechanically driven artificial speech device to be used by laryngectomees as an affordable alternative to an electrolarynx (EL). Design objectives were based on feedback from potential end users. The device implements a mainspring powered gear train that drives a striker. The striker impacts a suspended drum-like head, producing sound. When pressed against the neck, the head transmits sound into the oral cavity, allowing the user to produce intelligible speech. The dynamics of the vibrating head and sound pressure levels (SPLs) produced at the mouth were measured to compare performance between the device and a common, commercially available EL. The results showed comparable performance and sound output.

Development and perceptual evaluation of amplitude-based F0 control in electrolarynx speech

PURPOSE

Current electrolarynx (EL) devices produce a mechanical speech quality that has been largely attributed to the lack of natural fundamental frequency (F0) variation. In order to improve the quality of EL speech, in the present study the authors aimed to develop and evaluate an automatic F0 control scheme, in which F0 was modulated based on variations in the root-mean-square (RMS) amplitude of the EL speech signal.

METHOD

Recordings of declarative sentences produced by 2 male participants before and after total laryngectomy were used to develop procedures for calculating F0 contours for EL speech. Specifically, the positive linear relationship between F0 and RMS amplitude observed in pre-laryngectomy speech was used as the basis for generating an F0 contour based on the amplitude variation of EL speech. An analysis-by-synthesis approach was used to modify the F0 contour, and a perceptual experiment was conducted to examine its impact on the quality of the EL speech.

RESULTS

The results of perceptual experiments showed that modulating the F0 of EL speech using a linear relationship between amplitude and frequency made it significantly more natural sounding than EL speech with constant F0.

CONCLUSIONS

The current study provides preliminary support for amplitude-based control of F0 in EL speech.

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.