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Twelve judges, with no previous exposure to laryngectomees, rated the speaking proficiencies of 33 laryngectomees divided into the following groups: esophageal speakers (n = 12); electrolarynx speakers (n = 11); and tracheoesophageal puncture speakers (n = 10). In addition, the speech of ten normal subjects was rated. Specific speaking parameters examined included voice quality, pitch, loudness, intelligibility, rate of speaking, visual presentation during speech, extraneous speaking noise, and overall communicative effectiveness. Multiple discriminant analyses performed on the ratings made by each judge revealed significant differences in ratings for various speaking parameters in the four subject groups. Results generally support the stance that tracheoesophageal speech is perceived as superior to communication with either an electrolarynx or with traditional esophageal speech, even though it is not viewed as comparable to normal voice.

New means of speaking after laryngectomy or loss of continuity of the airway have consisted of: 1. Pharyngostome with artificial larynx (artificial mechanism connecting the trachea to the pharynx). 2. Artificial sound to nose or mouth (e.g., bellows, grammaphone). 3. A reed device from tracheostome to the mouth or the nose. 4. Tracheoesophageal fistula with or without a communicating connecting device. 5. Transcervical sound source which is used by placing a sound source on the external neck transmitting the sound into the pharynx. 6. The implanted sound source, or 7. Intra-oral sound source. This paper will review devices used to aid in artificial speech production provided in the past. No attempt will be made at reviewing the surgical literature on voice conservation procedures. Four sections are presented: 1. Early History of Laryngectomy and Review of Historical Artificial Larynges, 2. History of Alaryngeal Speech Production Without an Artificial Device, 3. Studies of Speech Production, Comparisons of Esophageal and Artificial Laryngeal Speech, and 4. Development of the Prototype Self-Contained Intra-Oral Artificial Larynx; synopsis of references reviewed in the first three sections; and a presentation of our new device in the fourth section. Each review is presented in chronological order with dates provided. Each of the first three sections is independent but relates to the common problem of alaryngeal speech. At the onset of design the self-contained intra-oral artificial larynx was thought to be only for persons after laryngectomy who for some reason could not attain esophageal speech. Later it became apparent that there are others, such as quadriplegics with tra-cheostomies, who could also benefit from an artificial larynx which is orally controlled. The artificial larynx being tested at present in our lab is fitted into a dental plate or dental shim with a hearing aid speaker and a built-in exponential horn which opens posteriorly. This artificial larynx is in its third revision and, at present, is externally wired during the testing phases. In its final form the power supply, electronic circuits, off-on switch, speaker and exponential horn will be completely contained in the dental prosthesis. Modifications are being made to obtain appropriate loudness with a decreased voltage requiring fewer batteries fitted into the prosthesis. The circuits will be placed on a microcomputer chip after the best circuits have been obtained by testing externally placed hard wired circuits on several objects.

An intra-oral artificial larynx includes a signal generator encapsulated within a custom-molded prosthetic means for mounting the larynx within the intra-oral cavity, as well as a speaker and tongue activatable switch for enabling the signal generator and the speaker. A compartment is molded in the custom-molded prosthetic means for receiving a power source, the power source being mounted on a carrier removably mounted in the compartment for powering the signal generator and speaker. The power source carrier is slidably received within the compartment and includes a means for isolating the compartment from saliva in the intra-oral cavity.

For those individuals unable to learn esophageal speech and for the period of time until adequate esophageal speech is developed, the successful use of an artificial larynx is of primary importance. The purpose of this paper is to present the results of an investigation which measured and analyzed the speech parameters of (1) rate, (2) duration, (3) pitch, (4) intensity, and (5) articulation of both good and poor artificial larynx users. In addition to the analysis of the above parameters, perceptual judgments of speech intelligibility and proficiency were obtained. The conclusions reached from this investigation have resulted in the establishment of criteria for training laryngectomized individuals in the use of an artificial larynx. The material presented can also be used as a diagnostic basis to determine why an individual is not functionally intelligible us using the artificial larynx.

The artificial larynx proposed in this paper can control the following features automatically: (a) voicing onset/cessation, (b) a brief stop in vibration for voiceless consonants, (c) variation in fundamental frequency, and (d) intensity for prosodic information. This device consists of three parts: (1) a detector of biological signals, i.e., sound, electromyograms (surface), air pressure and airflow, tactile information on the skin surface surrounding the larynx, etc.; (2) the controller for sound source, in which control parameters are derived from the biological signals; and (3) a sound source, which is to be implanted in the neck. To investigate the basic characteristics of the timing factors, (a) and (b) mentioned above, a manual operation scheme was examined by employing specially designed switches. The timing control is to be replaced by the remaining functions of the speech muscles. Also, a result of the experiment on the control of prosodic information, (c) and (d) above, using airflow, is presen...

This study investigated the acoustic characteristics of speech produced with an electronic artificial larynx (electrolarynx). Five normal‐speaking adult males were taught to use an electrolarynx, and each talker recorded a set of speech materials in his normal voice and with an electrolarynx. The recordings were subjected to analyses which included: (1) intensity level measurements of speech as well as the direct radiated sound from the electrolarynx; (2) speech‐duration measurements; (3) spectral analysis of the radiated masking sound from the electrolarynx; and (4) formant frequency estimates derived from the spectrum of a linear prediction inverse filter. Results indicated that the overall intensity of electrolarynx speech was similar for the five talkers, but that intensity of the radiated noise, and hence speech‐to‐noise ratios, varied considerably among talkers. In addition, talkers required about 50% more time to produce speech with an electrolarynx, indicating modification of articulatory behavior. Spectral composition of the radiated sound from the electrolarynx varied from talker‐to‐talker. Formant frequencies for a given talker were similar for the normal voice and the electrolarynx productions, but the intensity relationships between formants was different in the two modes of production. [Research supported by NINCDS and a grant from the Samuel W. Traylor Foundation.]

Since the development of the Western Electric reed type artificial larynx (Model 2) about thirty years ago, there has been a number of developments in the general fields of acoustics and electronic circuitry which are applicable to the design of an improved artificial larynx. An experimental model using some of these developments will be described and demonstrated. This new model is inconspicuous in use, and, as indicated by sound spectrographic analyses and articulation tests, has improved speech quality.

Accurate measurements of the human vocal tract damping, or the associated formant bandwidths, are not easy. Several different methods have been used by experimenters, with rather widely divergent results. Some of these methods are examined for sources of error, and the conclusions are checked by applying the same methods to the electrical vocal tract. This analog of the human tract can be held constant during a test, can be adjusted in damping, and can be measured accurately by single frequencies. More exact measurement of the real tract would seem to require an artificial source, applied in the pharyngeal cavity, having a lower fundamental and a more accurately known spectrum than the vocal cord tone. A few measurements are reported, obtained by means of an artificial larynx at 30 pulses/sec, applied to the outside of the throat wall. Analysis is made from a tape loop, by means of a narrow band wave analyzer. The results are not wholly satisfactory because the spectrum inside the tract is not accurately known.