Communication status following laryngectomy: the Iowa experience 1984-1987

Surface Electromyographic Activity in Total Laryngectomy Patients following Laryngeal Nerve Transfer to Neck Strap Muscles

Hands-free triggering and pitch control would improve electrolarynx devices, which are inconvenient to use and sound unnatural. The present study tested the strategy of salvaging voice-related neural signals for hands-free electrolarynx control either by transferring cut recurrent laryngeal nerves (RLNs) to denervated neck strap muscles or by preserving strap muscles with their normal innervation. An RLN nerve transfer was performed at the time of total laryngectomy in 8 individuals, and in 5 of these subjects, strap muscles with intact ansa cervicalis innervation were also preserved for comparison. Neck surface electromyography performed over the strap muscles was used periodically for more than 1 year on phonatory and nonphonatory tasks. Signals were eventually obtained in all subjects from both RLN-innervated and ansa-innervated strap muscles that correlated with speech production. After 1 year, RLN-driven signals were larger than ansa-driven signals in magnitude, and their timing appeared better correlated with intended phonation. The results show that neck surface electromyography is an effective control source for hands-free electrolarynx activation, and that RLN transfer may provide the best approach for obtaining phonation-related activity.

Development and evaluation of on/off control for electrolaryngeal speech via artificial neural network based on visual information of lips

OBJECTIVE

To realize an accurate and automatic on/off control of electrolarynx (EL), an artificial neural network (ANN) was introduced for switch identification based on visual information of lips and implemented by an experimental system (ANN-EL). The objective was to confirm the feasibility of the ANN method and evaluate the performance of ANN-EL in Mandarin speech.

STUDY DESIGN AND METHODS

Totally five volunteers (one laryngectomee and four normal speakers) participated in the whole process of experiments. First, trained ANN was tested to assess switch identification performance of ANN method. Then, voice initiation/termination time, speech fluency, and word intelligibility were measured and compared with button-EL and video-EL to evaluate on/off control performance of ANN-EL.

RESULTS

The test showed that ANN method performed accurate switch identification (>99%). ANN-EL was as fast as normal voice and button-EL in onset control, but a little slower in offset control. ANN-EL could provide a fluent voice source with rare breaks (<1%) for a continuous speech. The results also indicated that on/off control performance of ANN-EL had a significant impact on perception, lowering the word intelligibility compared with button-EL. However, the words produced by ANN-EL were more intelligible than video-EL by approximately 20%.

CONCLUSIONS

The ANN method was proved feasible and effective for switch identification based on visual information of lips. The ANN-EL could provide an accurate on/off control for fluent Mandarin speech.

Reconstruction of normal sounding speech for laryngectomy patients through a modified CELP codec

Whispered speech can be useful for quiet and private communication, and is the primary means of unaided spoken communication for many people experiencing voice-box deficiencies. Patients who have undergone partial or full laryngectomy are typically unable to speak anything more than hoarse whispers, without the aid of prostheses or specialized speaking techniques. Each of the current prostheses and rehabilitative methods for post-laryngectomized patients (primarily oesophageal speech, tracheo-esophageal puncture, and electrolarynx) have particular disadvantages, prompting new work on nonsurgical, noninvasive alternative solutions. One such solution, described in this paper, combines whisper signal analysis with direct formant insertion and speech modification located outside the vocal tract. This approach allows laryngectomy patients to regain their ability to speak with a more natural voice than alternative methods, by whispering into an external prosthesis, which then, recreates and outputs natural-sounding speech. It relies on the observation that while the pitch-generation mechanism of laryngectomy patients is damaged or unusable, the remaining components of the speech production apparatus may be largely unaffected. This paper presents analysis and reconstruction methods designed for the prosthesis, and demonstrates their ability to obtain natural-sounding speech from the whisper-speech signal using an external analysis-by-synthesis processing framework.

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.

Electromyographic control of a hands-free electrolarynx using neck strap muscles

Three individuals with total laryngectomy were studied for their ability to control a hands-free electrolarynx (EL) using neck surface electromyography (EMG) for on/off and pitch modulation. The laryngectomy surgery of participants was modified to preserve neck strap musculature for EMG-based EL control (EMG-EL), with muscles on one side maintaining natural innervation and those on the other side receiving a transferred recurrent laryngeal nerve (RLN). EMG from each side of the neck controlled the EMG-EL across a day of unstructured practice followed by a day of formal training, including EMG biofeedback. Using either control source, participants spoke intelligibly and fluently with the EMG-EL before formal training. This good initial performance did not consistently improve across testing for either control source in terms of voice timing, speech intelligibility, fluency, and intonation of interrogative versus declarative sentences. Neck strap muscles have activation patterns capable of simple alaryngeal voice control without requiring RLN transfer.

LEARNING OUTCOMES

The reader will better understand (1) functionality of the hands-free electrolarynx (2) modification of laryngectomy surgery to preserve neck strap musculature and (3) performance of hands-free electrolarynx with different control sources.

Neck and face surface electromyography for prosthetic voice control after total laryngectomy

The electrolarynx (EL) is a common rehabilitative speech aid for individuals who have undergone total laryngectomy, but they typically lack pitch control and require the exclusive use of one hand. The viability of using neck and face surface electromyography (sEMG) to control the onset, offset, and pitch of an EMG-controlled EL (EMG-EL) was studied. Eight individuals who had undergone total laryngectomy produced serial and running speech using a typical handheld EL and the EMG-EL while attending to real-time visual sEMG biofeedback. Running speech tokens produced with the EMG-EL were examined for naturalness by 10 listeners relative to those produced with a typical EL using a visual analog scale. Serial speech performance was assessed as the percentage of words that were fully voiced and pauses that were successfully produced. Results of the visual analog scale assessment indicated that individuals were able to use the EMG-EL without training to produce running speech perceived as natural as that produced with a typical handheld EL. All participants were able to produce running and serial speech with the EMG-EL controlled by sEMG from multiple recording locations, with the superior ventral neck or submental surface locations providing at least one of the two best control locations.

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.

Training effects on speech production using a hands-free electromyographically controlled electrolarynx

PURPOSE

The electrolarynx (EL) is a widely used device for alaryngeal speech, but it requires manual operation and produces voice that typically has a constant fundamental frequency. An electromyographically controlled EL (EMG-EL) was designed and implemented to provide hands-free control with dynamic pitch modulation.

METHOD

Three participants who underwent total laryngectomy surgery and 4 participants with normal voice were trained to produce EMG-EL speech through a multiple-baseline, successive-stage protocol. Baseline performance was established through 3 testing probes, followed by multiple hour-long training sessions.

RESULTS

At the end of the training, all participants learned to initiate, sustain, and terminate EMG-EL activation in correspondence with articulation, and most were able to modulate the pitch to produce intonational contrasts. After completing the testing/training protocol, 1 of the 3 participants who underwent total laryngectomy was encouraged to independently use the EMG-EL at his residence. This participant sustained his performance for an additional 6 weeks and also used the EMG-EL successfully to communicate over the phone.

CONCLUSIONS

Our findings suggest that some participants with laryngectomies and vocally normal individuals can learn to produce hands-free speech using the EMG-EL device within a few hours and that significant additional gains in device control (particularly pitch modulation) are attainable through subsequent training sessions.

Impact of aberrant acoustic properties on the perception of sound quality in electrolarynx speech

A large percentage of patients who have undergone laryngectomy to treat advanced laryngeal cancer rely on an electrolarynx (EL) to communicate verbally. Although serviceable, EL speech is plagued by shortcomings in both sound quality and intelligibility. This study sought to better quantify the relative contributions of previously identified acoustic abnormalities to the perception of degraded quality in EL speech. Ten normal listeners evaluated the sound quality of EL speech tokens that had been acoustically enhanced by (a) increased low-frequency energy, (b) EL-noise reduction, and (c) fundamental frequency variation to mimic normal pitch intonation in relation to nonenhanced EL speech, normal speech, and normal monotonous speech (fundamental frequency variation removed). In comparing all possible combinations of token pairs, listeners were asked to identify which one of each pair sounded most like normal natural speech, and then to rate on a visual analog scale how different the chosen token was from normal speech. The results indicate that although EL speech can be most improved by removing the EL noise and providing proper pitch information, the resulting quality is still well below that of normal natural speech or even that of monotonous natural speech. This suggests that, in addition to the widely acknowledged acoustic abnormalities examined in this investigation, there are other attributes that contribute significantly to the unnatural quality of EL speech. Such additional factors need to be clearly identified and remedied before EL speech can be made to more closely approximate the sound quality of normal natural speech.

Design and Implementation of a Hands-Free Electrolarynx Device Controlled by Neck Strap Muscle Electromyographic Activity

The electrolarynx (EL) voice prosthesis is widely used, but suffers from the inconvenience of requiring manual control. Therefore, a hands-free EL triggered by neck muscle electromyographic (EMG) activity was developed (EMG-EL). Signal processing circuitry in a belt-mounted control unit transforms EMG activity into control signals for initiation and termination of voicing. These control signals are then fed to an EL held against the neck by an inconspicuous brace. Performance of the EMG-EL was evaluated by comparison to normal voice, manual EL voice, and tracheo-esophageal (TE) voice in a series of reaction time experiments in seven normal subjects and one laryngectomy patient. The normal subjects produced voice initiation with the EMG-EL that was as fast as both normal voice and the manual EL. The laryngectomy subject produced voice initiation that was slower than with the manual EL, but faster than with TE voice. Voice termination with the EMG-EL was slower than normal voice for the normal subjects, but not significantly different than with the manual EL. The laryngectomy subject produced voice termination with the EMG-EL that was slower than with TE or manual EL. The EMG-EL threshold was set at 10% of the range of vocal-related EMG activity above baseline. Simulations of EMG-EL behavior showed that the 10% threshold was not significantly different from the optimum threshold produced through the process of error minimization. The EMG-EL voice reaction time appears to be adequate for use in a day-to-day conversation.

Comparison of pharyngoesophageal segment pressure in total laryngectomy patients with and without pharyngeal neurectomy

BACKGROUND

To compare pharyngoesophageal segment (PES) pressure values in total laryngectomy patients with and without pharyngeal neurectomy (PN) in the early postoperative period.

METHODS

Forty-five previously untreated laryngeal carcinoma patients were enrolled into this prospective randomized study. Twenty of them underwent total laryngectomy with PN, and 25 underwent total laryngectomy without PN. PES pressures were measured on the tenth postoperative day with a four-channel catheter.

RESULTS

Average PES pressures in patients with and without pharyngeal neurectomy were 12.82 +/- 6.11 mmHg and 17.40 +/-.72 mmHg respectively (p <.05). When compared with the critical point of 20 mmHg that is closely related to voice attainment in the group without pharyngeal neurectomy, 10 (40%) patients had pressure levels greater than 20 mmHg and in the other group only 1 (5%) patient had a pressure level greater than 20 mmHg. The difference between the groups with pressure levels greater than 20 mmHg was found to be statistically significant (p <.05).

CONCLUSIONS

Pharyngeal neurectomy results in a statistically significant decrease of PES pressures in total laryngectomy patients.

Prevention of pharyngoesophageal spasm after laryngectomy with a half-muscle closure technique

Because pharyngoesophageal spasm can limit successful voice restoration after total laryngectomy, 24 patients underwent a modified pharyngeal closure in an effort to avoid this problem. All patients underwent total laryngectomy with appropriate neck dissections and pharyngeal closure with a half-muscle closure technique in which only one side of the remnant constrictor muscles was used to reinforce the primary closure. Twenty-three patients underwent voice restoration. Twenty-two (96%) had a functional voice, and 1 patient (4%) had pharyngoesophageal spasm that required a secondary myotomy. One fistula (4%) occurred and resolved with conservative measures. Quantitative voice analysis demonstrated no significant differences between half-closure patients and control patients for fundamental frequency (96 Hz versus 101 Hz) or intensity (57 dB versus 64 dB). Extensive qualitative analysis by trained and naive listeners revealed no differences. This preliminary report indicates the half-muscle closure modification of the pharyngeal closure at primary laryngectomy may provide a simple and effective means of avoiding pharyngoesophageal spasm and maintaining an effective voice without increased complications.

Effects of sound pressure levels on fundamental frequency in tracheoesophageal speakers

The quality of tracheoesophageal (TE) voice after laryngectomy is dependent on numerous factors. The relative contribution of specific variables is not well described. To evaluate the modulation of fundamental frequency (F0) pitch in TE speakers after total laryngectomy and voice restoration, we instructed 11 TE speakers to complete a series of vocal tasks under standardized conditions. All patients underwent standard laryngectomy with appropriate neck dissection and full-course radiation therapy. Each speaker produced 4 sustained phonations at distinct levels. Sound pressure level (SPL) intensity and F0 measurements were taken for each level. Statistical analysis to assess the relative effect of SPL on F0 demonstrated a statistically significant effect. However, the knowledge of SPL allowed only a 9% greater prediction of F0, indicating that factors other than SPL are integral to the modulation of F0 by TE speakers. These data lend further support to the theory that TE voice is an active process incorporating the myoelastic properties of the pharyngoesophageal segment as well as the properties of aerodynamic flow.

Botulinum neurotoxin injection after total laryngectomy

BACKGROUND

One of several causes of tracheoesophageal puncture (TEP) speech failure after total laryngectomy is disturbance in relaxation of the pharyngoesophageal (PE) segment. We introduce the use of chemical denervation of the PE segment through botulinum neurotoxin (Botox) injection to improve TEP speech.

METHODS

An analysis was performed on eight patients who received Botox injections for TEP speech problems after total laryngectomy at the University of Iowa between June 4, 1991 and August 8, 1994. Retrospective chart review identified the evolution of pretreatment evaluation and injection technique which became standardized in April 1992. Prospective evaluation of results was recorded by a single speech pathologist who subjectively identified the response to Botox in all patients and recorded pressure readings at the tracheostoma site during speech in 6 patients.

RESULTS

Seven of the eight patients were noted to have improved TEP speech following injection. Five of these seven patients experienced substantially improved speech, three of whom had no ability to produce speech prior to the Botox injection.

CONCLUSION

Botox injection is a safe and effective method of improving TEP speech in selected patients with disturbed relaxation of pharyngoesophageal segment.

Voice Failure after Tracheoesophageal Puncture: Management with Botulinum Toxin

Primary or secondary tracheoesophageal puncture with a speaking prosthesis has provided rehabilitation of speech in most patients after total laryngectomy. Persistent constrictor spasm is thought to be responsible for a small percentage of these patients' inability to speak with the prosthesis. Management of these patients has included bougienage and pharyngeal myotomy and/or pharyngeal neurectomy. Botulinum toxin injections of the cricopharyngeus muscle complex in six patients have been successfully used diagnostically and therapeutically for tracheoesophageal puncture failures. The assessment, technique, and results are discussed.

Frequency and risk factors for voice problems in teachers of singing and control subjects

Using a questionnaire format, 125 teachers of singing and 49 control subjects indicated whether they had a current or past voice problem, and provided information about their demographic characteristics, voice use patterns, and medication use. The results revealed similar rates of current voice problems reported by the two subject groups. However, teachers of singing were considerably more likely to report ever having had a voice problem than controls (64 vs. 33%). Risk factors were similar for the two groups. Dehydrating medications and a report of a past voice problem both increased the likelihood of perceiving a current problem, by a factor of three and five, respectively. Females were twice as likely to report a past voice problem as males, and younger subjects were slightly more likely to report a past problem as compared with older subjects. The implications of the findings are discussed from a theoretical as well as pragmatic perspective.

Tracheoesophageal voice following tubed free radial forearm flap reconstruction of the neopharynx

Tracheoesophageal voice restoration after laryngectomy is possible with a variety of neopharyngeal reconstructions. We have used the tubed radial forearm free flap for neopharyngeal reconstruction since 1991. Six patients have undergone voice restoration with the Blom-Singer prosthesis and were available for quantitative and qualitative speech analysis. These patients were compared to five laryngectomy patients with standard pharyngeal closures and similar voice restorations. The free flap patients produced similar loudness levels compared to the standards with soft speech (52.06 dB and 47.19 dB, respectively) and loud speech (62.66 dB and 60.91 dB, respectively). The free flap patients demonstrated adequate intelligibility, with fundamental frequencies comparable to standards (124.82 Hz and 135.66 Hz, respectively), although with increased jitter (5.00% versus 1.96%). No differences were statistically significant, but evaluation by trained and naive listeners demonstrated significant differences in voice quality. This quantitative and qualitative and qualitative analysis of tracheoesophageal speech after radial forearm free flap reconstruction of the neopharynx demonstrates that acceptable voice can be achieved, but with limitations.

Long-term functional results after pharyngoesophageal reconstruction with the radial forearm free flap

For recovery to be deemed adequate, the laryngectomized patient requires restoration of both the ability to swallow and to speak. Immediate results and long-term functional recovery after pharyngoesophageal (PE) reconstruction with the radial forearm free flap were studied in 22 consecutive patients who had undergone primary (n = 3) or secondary (n = 19) reconstructions after total laryngectomy. Circumferential reconstructions were done in 13 patients (mean length 10 cm, range 6 to 16) and patch reconstructions in 9 patients (defect size range 4 x 4 cm to 8 x 7 cm). Flap leakage was evaluated for all patients, and postoperative diet and ability to swallow were evaluated for 16 patients with an intact tongue base. Voice was evaluated for 6 patients with circumferential reconstructions who had later undergone tracheoesophageal puncture with placement of a Blom-Singer voice prosthesis, and the results compared with those of a control group of 5 voice-restored patients who had undergone laryngectomy with primary closure of the pharyngoesophagus. All 22 flaps survived and none of the patients died. Although 7 (32%) reconstructions leaked, all but 1 closed spontaneously. Fourteen (88%) of the patients with an intact tongue base have no dysphagia and are on a regular diet, and 2 remain on an oral liquid diet. Compared with controls, patients with a radial free-flap reconstruction had similar loudness with soft speech (43 dB for controls versus 52 dB for radial patients) and loud speech (61 dB versus 63 dB), comparable fundamental frequencies (136 Hz versus 125 Hz), and increased jitter (2% versus 5%). Speech intelligibility was judged by untrained listeners as excellent for 4 of the patients with radial flaps and good for the other 2. The radial free flap offers the advantages of rapid harvest, high flap reliability, and minimal donor-site and patient morbidity. Leakage rate and deglutition restoration were similar to those of other reconstructions, including the free jejunal flap. Speech rehabilitation in patients secondarily reconstructed with the radial free flap was nearly equivalent to that of total laryngectomy patients who have primary closure of the pharynx and was superior to that reported with other popular PE reconstructions, including the gastric pull-up and the free jejunal flap.

Prosthetic voice restoration with the tracheostomal valve: a clinical experience

INTRODUCTION

Tracheoesophageal puncture (TEP) and use of a voice prosthesis is not a panacea for all laryngectomies. This report presents results of longitudinal treatment of 24 patients with secondary TEP followed longitudinally for 10 years in a private practice setting. Unique to this report is a focus on the use of the entire voice restoration system including both the voice prosthesis and the automatic tracheostomal valve.

METHODS

All patients referred for secondary TEP between 1982 and 1992 are included. Voice quality and the longevity of vocal restoration were ascertained. Clinical problems and their solutions are reported.

RESULTS

Immediate vocal restitution was achieved in 19 of 24 patients. Voicing was produced in two more patients within a few weeks. Four patients were not available for long-term follow-up because of death due to recurrent disease. Overall, 60% of patients were rated excellent and 5% rated fair in communication over a long-term period. Thirty-five percent were rated failure.

DISCUSSION

TEP and the use of the voice restoration system enabled both hands to be free during speaking and is achieved by many laryngectomies. Patient evaluation, training, and follow-up with team problem-solving may increase success rates using this approach.