Tracheo-esophageal speech with manual versus automatic stoma occlusion:
A multidimensional comparison.
Annelies Labaere 1, Jan Vanderwegen 2, Frans Debruyne 1 1 Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Belgium
2 Antwerp University Hospital, Department of Otorhinolaryngology, Antwerp, Belgium
Abstract Objectives: The objective of this study was to make a qualitative comparison between tracheo-esophageal speech with manual stoma occlusion and hands free tracheo-esophageal speech with the Provox FreeHands device.
Patients/Materials and Methods:
Both Manual and handsfree tracheo-esophageal speech were compared in 13 patients who were regular users of Provox Freehands for at least four months. Evaluation of speech material consisted of objective analysis using the KayPentax CSL, perceptual ratings by a group of experienced listeners and patients own perceptual judgment.
In addition, data concerning user-friendliness, additional values and inconveniences of the FreeHands device were gathered using questionnaires.
The Voice Handicap Index (VHI) was used to evaluate the relation between voice related QOL and method of stoma occlusion. Therefore a control group of TE-speakers who did not use hands free speech, was selected.
Objective analysis revealed significant differences (p< 0.05) for parameters fluency (i.e. the number of syllables produced on one intake of breath) and maximal phonation time, to the detriment of hands free speech. There were no significant differences found for the dynamic characteristics
Perceptual judgements of running speech were rated higher in the manual occlusion condition for most patients, but there were interrater differences.
Subjective impressions showed that the majority of patients preferred hands free speech to manual stoma occlusion, noticably for voice quality, fatigability, attractivity and feelings of self-confidence.
Major inconveniences of hands free speech were a significantly decreased duration of sticker adhesion, the occurrence of disturbing noises and the need for continued effort.
The VHI scores were significantly higher in the group of hands free speakers compared to the control group.
Conclusions: This clinical study showed that in selected patients the Provox FreeHands shows important subjective benefits. Improvements however are necessary to make the device a useful rehabilitation device for a larger group of laryngectomized patients.
Keywords: tracheo-esophageal speech, hands free speech, automatic tracheostoma valve
Loss of voice is considered as being the major handicap after a total laryngectomy. Since the first laryngectomies in 1866 and 1873 there has been an evolution in developing techniques for speech rehabilitation. Although in general survival chances have not changed a lot in the last 25 years, a growing attention for speech rehabilitation after surgery has lead to an important improvement of quality of life (Ackerstaff & Hilgers, 1996).
Tracheo-esophageal speech is considered as being the most effective way of alaryngeal speech. Advantages are the shortened revalidation time, the use of the normal respiratory system and the better quality of speech (Robbins et al., 1984; Blood et al., 1984; Fujimoto et al., 1991; Uwents et al., 1994; Max et al., 1996; Bruynooghe & Labaere, 2001).
A frequent reported disadvantage of this way of voice production is the need of using one hand to close the tracheostoma. This impedes doing bimanual tasks and attracts the attention to the impairment. (Blom et al, 1982; Singh, 1987; Verkerke et al 1994; 2002).
Hands free tracheo-esophageal speech was possible for the first time in 1982, when Blom et al have developed the automatic stoma valve.
The automatic stoma valve stays open when normal breathing, and closes when the exhalation airflow increases. When the valve is closed, the exhalation air is lead through the voice prosthesis and the PE-segment is brought in vibration. When expiration flow decreases, the valve reopens so that inspiration is possible again (Blom et al, 1982; Doyle et al, 1989).
Since then different types of tracheostoma valves have come onto the market. In our study Provox FreeHands HME (ATOS Medical) was used.
Provox Free Hands HME (fig 1) is an automatic tracheostoma valve with an integrated filter cassette. In contrast to most other types, the openings for breathing are on the side of the device. By increasing exhalation airflow, a membrane will unroll which closes the side openings and gives the patient the ability to speak. The valve in front makes coughing possible without loosing the device.
Fig. 1 Provox FreeHands with HME-cassette. The coughing valve is opened, the membrane is rolled. To Van As, 2002.
2. Patients/Materials and Methods To compare manual and automatic stoma occlusion 13 patients who use the automatic stoma valve on a regular base were selected.
The test group existed of 12 men and 1 woman. Their age varied between 40 years and 78 years, with a mean of 57 years.
To compare quality of life a control group was composed. Therefore we contacted the patients who had tried out the FreeHands system, but had not bought it for different reasons. 11 patients granted their cooperation.
The 13 participating FreeHands users had to fill in an identification form, the Voice Handicap Index and a questionnaire in which was asked for user-friendliness of the device and patient satisfaction.
The patients had to read a standard text and sustain the vowel /a/, first at a comfortable loudness and then as long, as loudly and as softly as possible, both with manual and automatic stoma occlusion. This way 26 speech samples were collected and registered on DAT-recorder.
The control group filled in an identification form, the VHI and a short questionnaire in which they could indicate their reason for not using FreeHands any more.
The selected objective parameters were speech rate (i.e. the number of syllables per minute), fluency (i.e. the number of syllables produced on one intake of breath), maximal phonation time (MPT), minimal and maximal intensity and dynamic range. Frequency measurements turned out to be impossible in 22 of the 26 samples since the vibration pattern was too deviant.
For the dynamic measurements we used the Computerised Speech Lab (CSL Model 47300B, Kay Elemetrics).
The perceptual judgement was done by six listeners who were used to hear pathological voices, but who were not familiar with hands free speech.
The listeners had to compare, for person 1 till 13, both speech samples. For the parameters naturalness, intelligibility, tension, disturbing noises, intonation/variation and general voice quality, they had to indicate which of both samples they found the best. The possibility ‘both samples are equal’ was also added. They did not know which of the samples were hands free spoken.
To examine the influence of hands free speech on the quality of life of our patients, the VHI’s of the test group and the control group were compared.
For statistical processing of the data we used SPSS 9.0
3. Results 3.1 Objective analysis There was a significant difference (p< 0.05) between automatic and manual stoma occlusion for the parameters MPT and fluency. In the manual stoma occlusion condition patients could on average sustain the vowel /a/ 4 seconds longer than in the hands free condition. With manual occlusion they could produce 11 syllables on one intake of breath , in contrast to 8 with automatic occlusion.
For the parameters tempo of speech and the dynamic characteristics no significant differences were found.
3.2 Perceptual evaluation When we focus on the results per patient, we can see that the speech of 3 persons was judged better when they were using FreeHands. For 3 other patients, the listeners reported no difference between both conditions. The hands free speech of 7 patients was found worse than their TE-speech with manual stoma occlusion, by the majority of the listeners.
On average, TE-speech with manual stoma occlusion is judged better than hands free speech for the parameters naturalness, intelligibility, tension and general quality of speech. Only for the parameter intonation/variation the listeners did not hear any difference in most of the cases (table 1).
Table 1: Comparison of both ways of stoma occlusion by means of 5 parameters. Judgements from 6 listeners for 13 patients.
In hands free speech, disturbing noise is reported in almost all cases, whereas in half of the speech samples with manual occlusion no noise is heard by the listeners (table 2).
Table 2. Comparison of both ways of stoma occlusion for the parameter ‘disturbing noise’. Judgements from 6 listeners for 13 patients.
No disturbing noises
slightly disturbing noises
Strongly disturbing noises
Free hands condition
3.3 Subjective patient judgement The majority of the patients of our test group preferred hands free speech, concerning quality of voice, fatigability, attractivity and feelings of self confidence (table 3).
Table 3. Comparison of both ways of stoma occlusion by means of 4 parameters. Judgements from13 patients.
Hands free better than or similar to manual occlusion
Hands free worse than manual occlusion
Almost all patients reported that the possibility to use both hands was the main advantage of the system. In addition a minority mentioned that their handicap was less remarkable with the free hands device.
As main disadvantage patients reported the decreased adhesion of the stoma stickers when using FreeHands. The difference in duration of adhesion was significant (p < 0,05). A second frequently reported disadvantage is the fact that hands free speaking is far more fatiguing than normal TE speech..
Furthermore the presence of disturbing noises during speech was experienced as very adverse. Noises were specified as audible hissing noise during inhalation, whistling during speech (caused by the adhesives coming loose) and an audible flop when the membrane closes.
The majority of the control group mentioned the higher cost of the device and the fact that hands free speech is more fatiguing as the main reasons to decide not to use FreeHands any more. Other motivations were the decreased adhesion, disturbing noises and decreased speaking volume.
3.3 Quality of life There was a significant difference between the FreeHands users and the control group for the VHI total score and the F-score (i.e. the functional component). The free hands group has higher scores, what corresponds with a lower quality of life.
4. Discussion and conclusions The objective measurements show worse results for hands free speech for the parameters MPT and fluency. These findings can be explained by the theory that the air consumption is larger when using the automatic valve. There are different causes for these increased air consumption. Firstly, hands free speaking requires a higher expiration force than manual stoma occlusion, on one hand to unroll the membrane, on the other hand to maintain this situation while speaking. An other reason is that there is a certain delay in fully closing the valve: during the unrolling of the membrane, a small amount of the expiration air can escape by the side openings. Figures 2a and 2b show these findings on the spectrograms of a sustained /a/, the first with manual occlusion, the second with automatic valve occlusion. On figure 2b we can see a burst of multifrequent energy (white arrow), followed by a smaller low frequency component (black arrow). Then a short break occurs, followed by the spectrum of the vowel /a/. These spectral characteristics correspond whit the moment on which the membrane unrolls (white arrow) and the valve closes (black arrow), and do not occur when the stoma is closed manually. They are found to a smaller or larger degree in the hands free speech of all patients.
Figure 2a. Spectrogram /a/ with manual stoma occlusion
This phenomenon does not only cause a larger air consumption during speech, but also leads to the presence of disturbing noise. In perceptual evaluation the occurrence of disturbing noises is reported in hands free speech of almost all patients, whereas this is much less the case in manual TE-speech. Other authors confirm this finding (Blakely& Podraza, 1987; Williams et al., 1989; Fujimoto et al., 1991).
By both the Free Hands users and the control group, the occurrence of noise, hissing sounds, flops and whistling was mentioned as a disadvantage of the system.
An important issue is the adhesion of the FreeHands device. Looking at individual findings in the test group, we see a group of patients in which the duration of adhesion does not differ according to the way of stoma occlusion. Nevertheless, in the other group the difference in duration is very large, from several days when using manual closure to some hours when using FreeHands.
These patients can only use the automatic valve occasionally during a short period and therefore mention the limited duration of adhesion as an important disadvantage of the system.
Previous studies also found out that the maintenance of an airtight seal between stoma valve and peristomal skin is the main problem of hands free TE-speech (Zanoff et al., 1996; van den Hoogen et al., 1996; Lewin et al., 1999).
Despite the in general less good results for hands free speech, both in objective as in perceptual evaluation, and the reported disadvantages by FreeHands users themselves, patients prefer the free hands condition.
We can conclude that in selected patients the Provox FreeHands shows important subjective benefits. Improvements however are necessary to make the device a useful rehabilitation device for a larger group of laryngectomized patients.
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