PROTHETIC DEVICE FOR ARTIFICIAL SPEECH

Abstract: A prosthetic tone emitter (SK) for laryngectomy patients which in combination with natural apparatus enables comprehensible speech. Components of the tone emitter are constructed into an artificial tooth (22) such that articulation is relatively unhindered.

Description: Description Prosthetic Device for Artificial Speech Technical Field This invention relates to sound producing prostheses which may be adapted for use by a number of patient groups, including laryngectomized patients. The human larynx functions to produce tones which are acted upon by naturally-occurring speech apparatus, the teeth, tongue, lips, etc., to produce sounds identified as human speech. Laryngectomized persons, or patients suffering from various other laryngeal or motor dysfunctions, are unable to produce the tones necessary to be shaped into words forming discernable human speech. Sound producing prostheses overcome this disability. Background Art Devices have been developed for enabling artificial speech. In general, these devices produce within the oral cavity a substitute tone which can then be modulated into speech. According to British Patent Specification 1 592872 of Lacey, sensing of an acoustic change on the opening of the mouth is supposed, in conjunction with his circuitry, to be sufficient to switch on his sound generator. Cooper's U.S. Patent No. 3,084,221 discloses a bite block switch to turn a sound emitter on and off as a function of jaw movement. Disclosure of Invention The instant invention provides a number of improvements over the prior art. Initially, a miniature sound emitter is installed in the human oral cavity, providing for concealment and non-interference with articulation. The tone emitter may be incorporated into into one, or a plurality of prosthetic teeth; or into a prosthetic dental plate, or may be simply inserted into the oral cavity and affixed to a natural or prosthetic tooth. The output tone frequencies and amplitude may be user specific, i.e., the energy spectrum generation capabilities of the circuitry may be designed to consider age and sex of the user, either being designed specifically for the individual user, or by frequency or amplitude tuning, or both. Additionally, the instant invention accomplishes elimination of the robotic or monotonous sound commonly associated with the use of electrolarynges by incorporation and use of a magnetic reed switch which is operated by articulation of the temporo- mandibular joint (TMJ-Activated Switch). Improvement A: In improvement A, major components of the tone emitter, named interoral electrolarynx, are incorporated into the interior of artificial teeth which are inserted into location where patients may lack a natural oral component, a tooth. The entire device may be incorporated in artificial teeth if the patient has sufficient space available for such placement. Research indicates that laryngectomized patients are generally edentulous to the point of three or more teeth, such that removal of healthy teeth will be rare. One embodiment comprises an artificial tooth containing a re¬ chargeable, replaceable battery; an artificial tooth containing a fixed miniature loudspeaker; and an artificial tooth containing microelectronic circuitry (fixed circuits). This embodiment may be accomplished with the use of novel precision prosthedontic appliances, such as the system manufactured by HADAX, SA, La Chaux-de-Fonds, Switzerland, invented by H. Hader. The artificial tooth, or teeth, added to the oral cavity of the user, actually improves articulation and speech quality by filling voids where natural teeth may be absent. This improvement A is particularly advantageous in that, by building the components of the electrolarynx into teeth, interference with articulation is substantially reduced or eliminated. This feature of the instant invention is in contrast to prior art wherein the physical presence of hand-held or invasive (e.g. tubular) devices prevent the natural speech apparatus (teeth, tongue, lips, etc.) from assuming the natural or appropriate positions necessary in the production of certain speech sounds, e.g., phrases, plosives, fricatives, zero-frequency sounds, etc., resulting in decreased quality speech. Improvement B: According to improvement B, the tone is activated (switched) by utilizing a microelectronic reed switch, such as the type used by CORATOMIC, INC., of Indiana, Pennsylvania, U.S.A., in the manufacture of cardiac pacemakers. This invention relies on the articulator capability of the temporo-mandibular (TM) joint to switch the reed switch. Use of the TM-activated reed switch is an improvement over the prior art: Lacey depends upon sensing noise in the vicinity of the user to activate his prosthetic device. Cooper relies upon a "bite block" to activate his device, which can easily become dislodged, if the user is careless. Improvement C: According to improvement C, the electrolarynx contains a storage means for delivering preplanned speech. This is accomplished by incorporation of encrypted circuits containing algorithms designed to duplicate energy and power spectrum-generation (microprocessor devices). While this improvement is of advantage of any patient, it is of particular advantage for those who have lost partially, or fully, the facility for using their natural oral apparatus. These patient classes include: stroke victims, trauma victims, Palsy victims, hemi-plegics, quadriplegics, and aphonic respirator-dependent persons. Brief Description of the Drawings The details of my invention will be described in connection with the accompanying drawings, in which Figure 1 is an electrical circuit diagram; Figure 2 is a diagrammatic plan view of a human oral cavity having an electrolarynx therein; Figure 3 is similar to Figure 1 with all components of the electrolarynx located within three artificial teeth; Figure 4 is a profile view of artificial teeth containing an electrolarynx; Figure 5 is a profile view of a switching facility; and Figure 6 is a partial plan view similar to Figure 1 of an alternative electrolarynx. Best Mode for Carrying Out the Invention General The invention is an oral cavity placed, minature sound emitter comprising an electrical circuit containing a power source, a speaker, or speakers, and other electrical components needed to produce an audible tone. The circuit may be concealed by incorporation into an artificial tooth or teeth, or concealed by incorporation into a denture plate or combination of a denture plate with artificial teeth, or the circuit may be concealed by mere location within the oral cavity either fixed to a tooth or teeth or to a denture plate or even unfixed. For the purposes of the claims and this specification, an artificial tooth is defined as a structure having the approxiate size and shape of a natural tooth and adapted in material strength and composition for substitution in an oral cavity for a natural tooth. The emitter generates a tone which can be shaped by natural apparatus, e.g. tongue, lips, palate and teeth, to form the sounds identified as human speech. Location of the emitter in the oral cavity is of significant advantage: generation of the sound directly in the oral cavity rather than externally results in a reduction in sound which escapes formation into speech and exists in the vicinity of the user as superfluous, background noise. Such background noise not only detracts from the quality of artificial speech, but may also be a source of embarassment. Location in the oral cavity reduces input power needed to produce normal speech intensity levels. The tone emitter can contain a storage means for delivering preplanned speech. For example, the emitter could contain taped or otherwise stored complete speech units to enable a preplanned, pretaped message. Alternatively, radio-telemetry can be used to deliver preplanned messages to an emitter in the mouth from a tape player outside the body. Preferably, miniaturized computer circuitry is used for this preplanned speech capability. Fricatives, plosives, white noise, pink noise, etc. can be stored in ROM or PROM chips and/or speech synthesizer technology used to get such sounds emitted as desired, for example by tongue-operated switches. An LM 3909 chip, available from Tandy Corp. (Radio Shack), is suitable for creating white and pink noise. Using miniaturized computer circuitry, entire speech synthesized messages can be brought into play. Tongue switches can be used to send serial or parallel, digital codes to evoke the different messages contained in storage. Location of the tone emitter in the oral cavity conceals the device, a social and psychological advantage. The tone emitter can have a variety of switching means for control (as example: magnetic reed switches, rocker dip switch, bio-feedback switch). Switches may be provided to turn the power on and off, for selecting different sound intensities, and even for the selection of discrete tone frequencies. Additionally, or alternatively, resistors and/or capacitors or other electrical components may be variable to control sound intensity and frequency over a range. The electrical circuit may be tunable to a frequency approximately appropriate to the age and sex of the user, or such matching may be done by selection of an appropriately designed model. Design and construction of a miniature electrical circuit to accomplish the above goals, is considered to be easily accomplished by persons of ordinary skill in the art. Albeit non-essential, in the following, a specific circuit embodiment will be disclosed. Multi-Vibrator Electrical Circuit Refer to Figure 1 which is a circuit diagram of one possible embodiment. The box labeled 555 is a number 555 integrated chip (a timer) which is a standard device. Table I supplies preferred embodients for electrical components. Closing switch SI causes a an ocillating electrical signal to be output across capacitor C2. Closing switch S2 passes the signal to speaker SK for emission of the basic tone. A miniaturized computer is shown for supplementing the basic tone with preplanned speech. TABLE I FIGURE 1 ELECTRICAL COMPONENTS Cl .01 mf C2 10 /uf Rl 1000 ohms R2 100K ohms 51 Rocker Dip Switch 52 Reed, or Proximity Switch V 1.5 to 30 VDC Battery Source SK Speaker where "/u" represents "micro-". Alternatively, other electrical circuits may be used. For example, the circuit described in Figures 2 and 3 of European patent application number 82102411.4 of Katz et al. entitled "Artificial Larynx", publication number 0061 702, filed 23.03.82, may be used. Placement in Oral Cavity Refer to Figures 2 and 3, which show examples of placement modes. In Figure 2, the emitter is constructed into a lower denture plate 11 which supports artificial teeth 12, of which three are so numbered: At least one artificial tooth, number 13, has constructed within it most of the electrical components needed for the emitter. Tooth 14 may be removable and contain a replaceable power source (battery). Speaker 15 emits the needed tone, and is shown located within plate 11, generally at the rear of the oral cavity. A plurality of speakers could be used, perhaps located in teeth 14 and 20. Necessary switches (corresponding to switches SI and S2 in Fig. 1) can be located in rear facing postions such as shown at 16 and 17, for activation by the tongue, or may be located in a forward facing position as at 18 for activation by a finger or hand held tool. Other electrical components such as resistors and capacitors, whose values may be varied, may be located to allow adjustment by replacement. Interconnecting wires in the circuit may be embedded in plate 11, as done in the system of HADAX mentioned above. The placement mode of Figure 2 shows the use of a denture plate. The emitter components are shown in Figure 2 to be distributed in several artificial teeth which are supported by plate 11. This design would be appropriate to a user with many missing natural teeth. The size and thickness of plate 11 is reduced by incorporation of components within artificial teeth 12. The optimum design is variable with the user but can be stated to be the incorporation of all components within a number of artificial teeth equal to .or less than the number of missing teeth in the oral cavity of the user, with no denture plate used. The entire emitter would be within artificial teeth and the articulation of sound would be done with an essentially intact, unobstructed oral cavity, i.e., the device will not interfere with articulation. In Figure 3, an emitter is illustrated which is appropriate to a user having 3 missing adjacent molars. No plate is used. Teeth 21 and 25 are natural teeth to which artificial teeth 22, 23 and 24 are attached. The means of attachement is well known to the art of dentistry and is also described (dental wires) in the above-mentioned Katz et al. European application. Another method of placement is a process called investment casting, wherein a geltrate mold of the tooth is taken and a precision appliance is constructed to the exact configuration of the tooth. This procedure is common in dental practice and, while more expensive than wires, is better protective against periodontitis, or corrosion of the dentin. Artificial tooth 22 will contain a speaker, with the face of the speaker facing into the oral cavity and away from the cheek. Artificial tooth 23 is a removable tooth which contains a battery power supply for the circuit of the electrolarynx. The remaining components of the circuit, including at least one switch, is in artificial tooth 24. Figure 4 shows a profile of the emitter in which natural teeth 21, 25 support artificial teeth 22, 23, and 24 via wires 26. Item 27 is a switch (corresponding to switch S2 in Fig. 1) which controls the sound tone. Artificial tooth 22 contains speaker 15 and artificial tooth 23, a removable tooth, contains a battery. Electrical connections between the artificial teeth may be via wires 26, or precision prosthodontal appliances which support the appliance. A object of this invention is to provide a minimum of interference with articulation. Consequently, the embedding of components within artifical teeth should be such as to present a smooth tooth face on both sides of the tooth. On the buccal, cheek side of the tooth, a smooth surface prevents sores. On the lingual, cavity side, a smooth surface optimizes articulation. Speaker 15 must penetrate to the outer surface of artificial tooth 22 to increase sound transmission, but may be flush with the flat surface. In Figure 3, no protrusion of speaker 15 beyond tooth 22 is shown. The battery may be wholly encased within artificial tooth 23, with only electrical connectors penetrating to the surface of the tooth. The entire artificial tooth 23 may be removed and replaced, to enable recharging. The device of H. Hader (see above) may be used to facilitate this. Switch 27 will protrude somewhat into the oral cavity 30 but presents only minimal obstruction to articulation. The elimination of a plate should reduce the occurrence of sores in the mouth of the user due to vibration rubbing. The inclusion of a battery and a speaker within artificial teeth has been demonstrated in a bench mockup of a human oral cavity using commercially available components. A battery sold by Gould (Activair 2, 312 HP) is considered suitable, as is a Knowles BK-1610 speaker. Refer to Figure 5 which illustrates the use of a magnetic or compression contactor 31 to activate switch 32 corresponding to switch S2 of Fig. 1. When lower jaw 33 and upper jaw 34 separate to open the mouth, contact or proximity of contactor 31 with switch 32 is lost, thus activating switch 32 to generate the tone. The contactor places the switch into an electrically non-conductive position when the jaws are closed and into an electrically conductive position when the jaws are open. Contactor 31 is held to tooth 39 in upper jaw 34, while switch 32 is held to tooth 40 in lower jaw 33. For example, contactor 31 may be bonded to the lingual side of tooth 39, while switch 32 is bonded to the lingual side of tooth 40. In the case of a compression switch, the contactor can be the tooth itself. In the case of a magnetic switch, a magnetic contactor 31 may be encased within an artificial tooth 39, while switch 32 is encased within an artificial tooth 40; in this case, the switch and contactor are absolutely concealed and present no hindrance to articulation of speech or chewing of food. Wiring of the switch into the tone producing- circuit may be by one of the methods explained above. The magnetic switch and/or its contactor may be buried at different depths in the teeth, or switches of different sensitivity may be used, to vary the time of switch-on as the jaws open. Also, a plurality of magnetic switches may be emplaced, in order to switch-on different sound circuits at different amounts of jaw opening. Placement of these magnetic reed switches at varying depths throughout the dental arcade can switch-on variable modulations, or tones, to facilitate even singing. A suitable reed switch is Hermetic Switch HRS 003 DT-C (pull- up range 5-10) from Hermetic Switch, Inc., Chickasha, OK 73018, U.S.A.. This switch may be operated using a sintered Alnico magnet Part No. 28C86A from Permag Magnetics Corp., Toledo, Ohio 43609, U.S.A.. Refer to Figure 6 which illustrates an embodiment suitable for a user with all natural oral components intact. At least one insert 36 is removably attached to natural teeth 12, which insert 35 contains the emitter. Switches 36 are shown positioned for tongue actuation. Attachment means 37 secures insert 35 via gaps 38 between teeth 12.

Claims: Claims WHAT IS CLAIMED IS: Improvement A: 1. A tone emitter for the electrical generation of a sound tone for artificial speech, which tone emitter is sufficiently small in size and 5 adpated for placement entirely within a human oral cavity, wherein the improvement comprises that a component of the tone emitter is contained in a tooth. 2. The tone emitter of claim 1, wherein the improvement comprises a first removable, artificial tooth which contains a battery power source 0 and a second artificial tooth which contains a speaker. 3. The tone emitter of claim 2, wherein said speaker is substantially encased within said artificial tooth. 4. The tone emitter of claim 2, further containing a switch for selectively operating the tone emitter, and a circuit operatively 5 associated with said power source, speaker and switch whereby the tone emitter may selectively generate a sound tone for the production of artificial speech. 5. " The tone emitter as claimed in claim 4, the switch means being positioned for tongue actuation and including a switch for turning the 0 power source on and off. Improvement B: 6. A tone emitter for the electrical generation of a sound tone for artificial speech, which tone emitter is sufficiently small in size and adpated for placement entirely within a human oral cavity, wherein the 5 improvement comprises a switch held with respect to one jaw and a contactor held with respect to the other jaw, the contactor placing the switch into one position when the jaws are closed and into a second position when the jaws are open, such that the tone may be initiated by the act of opening the mouth. 0 7. The tone emitter of claim 6, the contactor and switch each being bonded to the side of a tooth. 8. The tone emitter of claim 6, the switch being a magnetic proximity switch. 9. The tone emitter of claim 8, at least one of the contactor and 5 switch being encased within an artificial tooth. 10. The tone emitter of claim 9, both the contactor and the switch being so encased. Improvement C 11. A tone emitter for the electrical generation of a sound tone for artificial speech, wherein the improvement comprises a storage means for delivering preplanned speech. 12. The tone emitter of claim 11, wherein miniaturized computer circuitry is used for a preplanned speech capability. 13. The tone emitter of claim 12, further including a speech synthesizer. 14. The tone emitter of claim 12, wherein tongue switches are used to send serial or parallel, digital codes to evoke different messages contained in storage.

Inventors: RESNICK JOSEPH A, RESNICK, JOSEPH, A.
Applicants: RESNICK JOSEPH A, RESNICK, JOSEPH, A.
Application year: 1985
Main classification: G10L3
IPC codes: A61F2