EP2675395B1

EP2675395B1 - Voice prosthesis

Info

Publication number: EP2675395B1
Application number: EP12705495.5A
Authority: EP
Inventors: Eduard Berend Van Der Houwen
Original assignee: Rijksuniversiteit Groningen; Academisch Ziekenhuis Groningen
Current assignee: Rijksuniversiteit Groningen; Academisch Ziekenhuis Groningen
Priority date: 2011-02-16
Filing date: 2012-02-13
Publication date: 2019-02-13
Anticipated expiration: 2032-02-13
Also published as: EP2675395A1; WO2012112033A1

Description

The invention relates to a voice prosthesis for a human, for example a laryngectomized patient not having vocal folds anymore, or a person (e.g. a singer) who is advised by a physician not to use or to save his or her vocal folds.
Laryngeal cancer is the most common cancer in the head-and-neck region. In recent years there is a trend of a few percent increase of incidence in head-and-neck tumors, due to tobacco and alcohol use and ageing of the population. Severe cancer in the laryngeal or hypopharyngeal region often requires a total laryngectomy, i.e. excision of the larynx (including vocal folds). Reconstruction is performed by leading the trachea outside. The trachea then ends in an opening in the neck, the so-called "tracheostoma". After this operation, voice restoration usually takes place by tracheo-esophageal puncture and the insertion of a one-way valve ("shunt valve") in the puncture. In other words, such a shunt valve is inserted in the wall between the trachea and the esophagus. By closing the tracheostoma (manually or by means of a so-called "tracheostoma valve"), exhalation air flows through the shunt valve to an air chamber enclosed by soft tissue at the top of the esophagus, which then starts to vibrate and acts as new "vocal folds". Such "tracheo-esophageal speech" using shunt prostheses nowadays is more or less accepted as the standard way to produce voice of reasonably acceptable quality.
However, in spite of advances in radiotherapy, laryngeal surgery and speech therapy, voice rehabilitation is not always successful in patients treated for laryngeal cancer. Several patients never regain full speech recovery. For some patients voice cannot be generated due to hyper- or hypotonicity. Also voice quality is sometimes poor, difficult to understand and also not gender-discriminative (the voice of a female often sounds mannish). Furthermore leakage through or around the prosthesis leads to frequent replacements of the prostheses with an impact on the quality of life of the patient.
US4571739A discloses a voice prosthesis according to the preamble of claim 1. Components of this known voice prosthesis are embedded within a plurality of artificial teeth. In one embodiment, illustrated by Fig. 2 of US4571739A , the artificial teeth in which components of the prosthesis are embedded are part of a combination of a denture plate with artificial teeth. In that embodiment some components of the prosthesis, such as a speaker and wires that interconnect components of the prosthesis are embedded in the denture plate of the prosthesis. In another embodiment, illustrated by Figs. 3-5 of US4571739A , no denture plate is used and the prosthesis has wires between the artificial teeth, which wires provide electrical interconnections between components of the prosthesis. Some drawbacks of these voice prostheses known from US4571739A are as follows. Their realization is laborious and expensive, not only because of the complex structure of these voice prostheses, but also because the realization is highly tailor-made for every individual user of such a prosthesis. Furthermore, once the known voice prostheses have been realized, users have to regularly perform extra and extensive cleaning of the prostheses and of their teeth/oral cavity in order to prevent further discomforts or ailments. Also it is disadvantageous that potential users who do not have sufficient empty tooth locations must be willing to permit extraction of a number of natural teeth in order to make use of this known voice prosthesis. Furthermore it is clear that this known voice prosthesis in most cases will not be interesting for potential users that only temporarily need a voice prosthesis, such as e.g. a singer who is advised by a physician not to use or to save his or her vocal folds only temporarily.
It is an object of the invention to provide a solution according to which voice generation is improved for a person who is not or not fully relying on vocal folds, which solution is noninvasive, immediately usable, usable in a simple and intuitive manner by the person and available at low cost-price.
For that purpose, the invention provides a voice prosthesis for a human comprising: at least one electrical energy source; at least one speaker; at least one speech intention detector for detecting a condition of a human, which condition is indicative of the intention of the human to speak; and a control structure arranged for controlling the operation of said speaker at least by means of electrical energy delivered by said electrical energy source and at least in dependence of detection by said speech intention detector; wherein the external shape of the voice prosthesis equals the external shape of a flat tablet for intra-oral use by a human and dimensioned to be intra-orally held into a cheek of a human with one flat side of the voice prosthesis facing the upper and lower jaws of that cheek and with the other, opposite flat side of the voice prosthesis facing the enveloping flesh of that cheek.
The voice prosthesis according to the invention, which is in the form of a flat tablet, can be nonattachably placed and held into the cheek of the mouth of a user (similar to a peppermint or the like) and is therefore noninvasive and immediately usable. The at least one speech intention detector for detecting an intention of the user to speak may for example detect opening of the user's mouth by means of detecting light and/or air flow and/or air pressure difference and/or otherwise, and/or may for example detect a press by the user's finger on his or her cheek and/or a press of the user's tongue on the voice prosthesis. Upon such detection, the at least one speaker may emit a clearly audible tone. Thus, the at least one speaker, the at least one speech intention detector and the control structure allow the user to articulate by him- or herself a clearly audible tone, emitted by the at least speaker, into audible, clear and pleasantly sounding speech. Therefore, the voice prosthesis according to the invention is usable in a simple and intuitive manner. The voice prosthesis according to the invention can be produced in large numbers. Also, nowadays, miniaturized electronic acoustic transducers, sensors and advanced signal processing devices are readily available at low cost-price. Therefore, the voice prosthesis according to the invention can be made available to users at low cost-price. It may be made available to a patient directly after surgery or after any other procedure that prohibits use of patient's vocal folds.
Clearly the voice prosthesis according to the invention takes away the abovementioned drawbacks of the voice prostheses known from the abovementioned document US4571739A . After all, applying the voice prosthesis according to the invention to a user is simple and not necessarily tailor-made for every individual user, cleaning is easy, there is no need to extract a number of natural teeth, and the voice prosthesis according to the invention is ideal for users that only temporarily need a voice prosthesis, such as e.g. a singer who is advised by a physician not to use or to save his or her vocal folds only temporarily.
Furthermore it is remarked that the abovementioned document US4571739A explicitly discourages solutions other than fixing prosthesis parts at locations of one or more teeth. For example in column 1 lines 34-42 of US4571739A it is asserted that such other solutions have the disadvantage of interference with the articulation needed to shape the tone into the sounds which are identified as speech. US4571739A explains that the physical presence of a prosthetic device located within the oral cavity, but its parts not being at locations of one or more teeth, may prevent the lips and tongue from assuming the positions appropriate to specific sounds or words, or the device may reflect sound waves. However, fully against this discouraging assertion explained in US4571739A , the inventor of the present invention has devised a voice prosthesis for intra-oral use at a place other than locations of one or more teeth. Surprisingly and unexpectedly the inventor has found that interference with articulation is negligible for the prosthesis devised by him. When the voice prosthesis according to the invention is placed in the cheek, as allowed by its external flat tablet shape, the lips and tongue movements are not hampered, while in the cheek the prosthesis for a great part is shielded in such manner that reflection of sound waves is prevented to a large extent.
The voice prosthesis according to the invention can be either single-use or rechargeable. Its main parts, such as batteries, speakers, amplifiers, sensors and control structures nowadays are readily available in micro sizes. A miniature amplifier generating about 1-3 Watt will generally suffice.
The mentioned intra-oral use of the voice prosthesis according to the invention into the cheek makes that certain dimensions of the flat tablet shape of the prosthesis are favourable. In order to specify such favourable dimensions, in particular in respect of the surface area of a "planform" of the flat tablet, in respect of the maximum thickness of the flat tablet and in respect of a ratio of flatness of the tablet, the following definitions are used in the present document.
The "flatly projected surface area" of the voice prosthesis according to the invention is defined as the surface area, as measured in a straight reference plane, of the projected area obtained by perpendicular projection of the voice prosthesis onto said reference plane, said reference plane being chosen to be oriented such that said measured surface area is maximum.
The "maximum thickness" of the voice prosthesis according to the invention is defined as being measured in a direction perpendicular to said straight reference plane.
The "flatness ratio" of the voice prosthesis according to the invention is defined as the quotient in which the numerator is the square root of said flatly projected surface area of the voice prosthesis and the denominator is said maximum thickness of the voice prosthesis.
It is remarked that said projected area in said reference plane may in general have various shapes. For example, the outline of said projected area in said reference plane may be substantially circular, oval, polygonal (such as octagonal, hexagonal, rectangular or square, etcetera), or may be of various other shapes, or of various piecewise interconnections of different shapes, etcetera.
Preferably, the flatly projected surface area of the voice prosthesis according to the invention is in-between 200 mm² and 1400 mm², more preferably in-between 300 mm² and 900 mm², yet more preferably in-between 400 mm² and 700 mm². These preferable embodiments provide the advantages that the prosthesis is reliably held into the cheek, while allowing movements, substantially in the sagittal plane of the user, of the upper and lower jaws towards and away from one another, and provide comfortable reception of the prosthesis in the cheek as seen substantially in the sagittal plane of the user.
In combination with any one of the already mentioned preferable embodiments of the invention, the maximum thickness of the voice prosthesis according to the invention preferably is at most 15 mm, more preferably at most 10 mm, yet more preferably at most 8 mm. These preferable embodiments provide comfortable reception of the prosthesis in the cheek as seen substantially in the frontal plane of the user.
In combination with any one of the already mentioned preferable embodiments of the invention, the flatness ratio of the voice prosthesis according to the invention preferably is at least 1.5, more preferably at least 2.5, yet more preferably at least 3.0. These preferable embodiments provide the advantages that the prosthesis is reliably held into the cheek, while allowing movements, substantially in the sagittal plane of the user, of the upper and lower jaws towards and away from one another, and provide comfortable reception of the prosthesis in the cheek as seen both substantially in the sagittal plane and substantially in the frontal plane of the user.
In yet another preferable embodiment of the invention, which can be applied in combination with any one of the already mentioned preferable embodiments of the invention, the at least one speech intention detector comprises at least one optical sensor for detecting, during said intra-oral use of the voice prosthesis by a human, a condition in which the human opens his or her mouth indicative of the intention of the human to speak. This provides the advantages that the user can initiate speech in an easy, natural and intuitive way.
In yet another preferable embodiment of the invention, which can be applied in combination with any one of the already mentioned preferable embodiments of the invention, the voice prosthesis further comprises at least one intra-oral use detector for detecting a condition indicative of whether the voice prosthesis is in intra-oral use. This provides the advantage that the prosthesis can be brought automatically in operation mode, which provides ease for the user. Said at least one intra-oral use detector may comprise for example one or more switches arranged for detecting a press by the user's finger and/or a press by the user's tongue. Preferably, said at least one intra-oral use detector comprises at least one electric conductivity sensor.
In yet another preferable embodiment of the invention, which can be applied in combination with any one of the already mentioned preferable embodiments of the invention, the voice prosthesis further comprises at least one orientation detector for detecting, during said intra-oral use of the voice prosthesis by a human, a change in orientation of the head of the human. This provides the advantage that the user, via movements of his or her head (e.g. tilting movements), can transmit control instructions to the prosthesis, for example for intonating up or down. If, for example, the user wants to produce an interrogative sentence, the user may for example tilt his or her head at the end of the sentence, whereby the prosthesis intonates up at the end of the sentence.
In yet another preferable embodiment of the invention, which can be applied in combination with any one of the already mentioned preferable embodiments of the invention, the voice prosthesis is packed in a blister pack. This provides the advantages of ease and hygiene. A single voice prosthesis can be packed in a blister pack having a single compartment for that single voice prosthesis only. However, individual ones of a plurality of voice prostheses can also each be packed separately in individual compartments, respectively, of a blister pack having multiple compartments. In the lastmentioned case a user will be able to take a fresh prosthesis from the blister pack, for example on a regular basis, such as daily, every other day or weekly, etcetera.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment described hereinafter, by way of non-limiting example only, with reference to the schematic drawing, in which:

Fig. 1 shows, in perspective view, an example of an embodiment of a voice prosthesis according to the invention which is intra-orally held into a cheek of a human;
Fig. 2 shows part of the example of Fig. 1 in a cross-sectional plane being parallel to the frontal plane of the human; and
Fig. 3 shows the voice prosthesis of Figs. 1 and 2 when perpendicularly projected on a straight reference plane R being parallel to the sagittal plane of the human.

In Fig. 1 the voice prosthesis 1 according to the invention is indicated in broken lines. In Fig. 1 the prosthesis 1 is intra-orally held into the left cheek of a person 2.
The cross-sectional plane of Fig. 2 shows said left cheek's upper jaw 14, including a corresponding upper molar 19, and said left cheek's lower jaw 15, including a corresponding lower molar 20. Fig. 2 also shows said left cheek's enveloping flesh 16. The prosthesis 1 has an external shape 18 which equals the external shape of a flat tablet for intra-oral use by a human. In Fig. 2 it is seen that one flat side 11 of the prosthesis 1 is facing the upper and lower jaws 14, 15, whereas the other, opposite flat side 12 of the prosthesis 1 is facing the enveloping flesh 16. Preferably, the prosthesis 1 is arranged in such manner that users are able to distinguish from its outside appearance that the flat side 11 is the flat side of the prosthesis 1 which preferably has to face the upper and lower jaws 14, 15 when the prosthesis 1 is placed into the cheek. For that purpose the prosthesis 1 may for example be provided with a readable indication on the exterior side of flat side 11, such as a readable letter string "Jaw Side", or the like.
In the shown example, the prosthesis 1 comprises at least one electrical energy source in the form of a battery 3, at least one speaker in the form of loudspeaker 4, at least one speech intention detector in the form of three optical sensors 5, 6 and 7, and a control structure in the form of micro-electronic circuitry structure 8 arranged for controlling the operation of the speaker 4 at least by means of electrical energy delivered by the battery 3 and at least in dependence of detection by at least one of said optical sensors 5, 6 and 7. The speaker 4 and the optical sensors 5, 6 and 7 are located nearby the flat side 11 of the prosthesis 1 which is facing the upper and lower jaws 14, 15. Accordingly, the exterior boundary wall structure of the prosthesis 1 is arranged to be sufficiently transparent for sound generated by the speaker 4 and for incident light to be received by the optical sensors 5, 6 and 7.
In the shown example, the prosthesis 1 furthermore comprises at least one intra-oral use detector 9 for detecting a condition indicative of whether the voice prosthesis 1 is in intra-oral use. In the example the at least one intra-oral use detector is formed by an electric conductivity sensor 9 located at the flat side 12 of the prosthesis 1 which is facing the enveloping flesh 16 of the cheek.
In the shown example, the prosthesis 1 furthermore comprises at least one orientation detector 10 for detecting, during said intra-oral use, a change in orientation of the head of the person 2.
In the shown example, the prosthesis 1 furthermore comprises a command switch 17.
All electrical components, including the sensor 9, the detector 10 and the switch 17 are communicatively connected with the micro-electronic circuitry structure 8.
In Fig. 2 there is also indicated a straight reference plane R. The reference plane R is chosen to be oriented such that the surface area (as measured in the reference plane R) of the projected area obtained by perpendicular projection of the voice prosthesis 1 onto the reference plane R is maximum.
Fig. 3 shows said projected area, indicated by the letter P, in the reference plane R. In Fig. 3 projections of only some of the components of the prosthesis 1 have been indicated with the same reference numerals as the corresponding components themselves, i.e. the projections of the speaker 4, of the optical sensors 5, 6, and 7, and of the command switch 17.
In Fig. 2 there is also indicated the maximum thickness T of the voice prosthesis 1, which maximum thickness T is being measured in a direction perpendicular to the reference plane R.
Operation of the shown prosthesis 1 is briefly explained as follows. The prosthesis is put into its stand-by mode using the command switch 17. The electric conductivity sensor 9 detects whether the prosthesis 1 is present in the mouth of a user and, if so, the prosthesis turns in operation mode. Once in operation mode, the prosthesis, in response to detecting opening of the user's mouth by means of at least one of the optical sensors 5, 6 and 7, emits an acoustical signal from the speaker 4 (alternatively, the signal could also be initiated by the user pressing on his or her cheek, detected by sensor structure of the prosthesis 1). This signal is strong and clear enough to allow the user the articulate it into intelligible speech.
The signal may for example stop at a programmed time after closure of the mouth. The signal itself may for example fluctuate as not to sound monotonous. The user can intonate up or down by means of changing the position of his or her head, detected by the orientation detector 10. Additionally or alternatively, the prosthesis may randomly, or periodically, intonate up or down after a programmed time of activation upon subsequent openings of the mouth. The prosthesis will switch off after detecting to be taken out of the mouth, or for example after being switched off by the user via the command switch 17.
The prosthesis 1 is made up of materials which are harmless to the human body, even in case a user would inadvertently swallow the prosthesis. For example, the prosthesis 1 may contain a harmless battery, known in the art and used in swallowable cameras for use in the human intestines.
In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader scope of the invention as set forth in the appended claims.
For example, various shapes of the prosthesis in various cross-sectional planes, such as in the cross-sectional plane of Fig. 2, are possible, such as oval, polygonal (such as octagonal, hexagonal, rectangular or square, etcetera), or various other shapes, or various piecewise interconnections of different shapes, etcetera. Furthermore, the external shape of the voice prosthesis may locally have protrusions and/or recesses and/or openings of various shapes and distributions over the external shape.
Also, the prosthesis may be arranged such that the emitted acoustical signal carries messages to the user directly, either by melody, beeping or spoken word, conveying information about the internal condition of the device, settings or sensor status. Furthermore it is remarked that the voice prosthesis according to the invention, besides its use to restore speech, can also be used to alter voice, imitate other voices, sing voice more simultaneously, or the like.
However, other modifications, variations and alternatives are also possible. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

Claims

A voice prosthesis for a human (2) comprising:
- at least one electrical energy source (3);

- at least one speaker (4);

- at least one speech intention detector (5, 6, 7) for detecting a condition of a human, wherein said condition is indicative of the intention of the human to speak; and

- a control structure (8) arranged for controlling the operation of said speaker at least by means of electrical energy delivered by said electrical energy source and at least in dependence of detection by said speech intention detector;
characterized in that the external shape (18) of the voice prosthesis (1) equals the external shape of a flat tablet for intra-oral use by a human and dimensioned to be intra-orally held into a cheek of a human with one flat side (11) of the voice prosthesis facing the upper (14) and lower jaws (15) and with the other, opposite flat side (12) of the voice prosthesis facing the enveloping flesh (16) of that cheek.
A voice prosthesis according to claim 1, wherein a flatly projected surface area of the voice prosthesis (1) is in-between 200 mm² and 1400 mm²,
said flatly projected surface area being defined as the surface area, as measured in a straight reference plane (R), of the projected area (P) obtained by perpendicular projection of the voice prosthesis onto said reference plane (R), said reference plane (R) being chosen to be oriented such that said measured surface area is maximum.
A voice prosthesis according to claim 2, wherein said flatly projected surface area of the voice prosthesis (1) is in-between 300 mm² and 900 mm².
A voice prosthesis according to claim 3, wherein said flatly projected surface area of the voice prosthesis (1) is in-between 400 mm² and 700 mm².
A voice prosthesis according to any one of the preceding claims, wherein a maximum thickness (T) of the voice prosthesis (1) is at most 15 mm,
said maximum thickness (T) being defined as being measured in a direction perpendicular to a straight reference plane (R),
said straight reference plane (R) being chosen to be oriented such that the surface area, as measured in said straight reference plane (R), of the projected area (P) obtained by perpendicular projection of the voice prosthesis onto said reference plane (R) is maximum.
A voice prosthesis according to claim 5, wherein said maximum thickness (T) of the voice prosthesis (1) is at most 10 mm.
A voice prosthesis according to claim 6, wherein said maximum thickness (T) of the voice prosthesis (1) is at most 8 mm.
A voice prosthesis according to any one of the preceding claims, wherein a flatness ratio of the voice prosthesis (1) is at least 1.5,
said flatness ratio being defined as the quotient in which the numerator is the square root of a flatly projected surface area of the voice prosthesis and the denominator is a maximum thickness (T) of the voice prosthesis (1),
said flatly projected surface area being defined as the surface area, as measured in a straight reference plane (R), of the projected area (P) obtained by perpendicular projection of the voice prosthesis onto said reference plane (R), said reference plane (R) being chosen to be oriented such that said measured surface area is maximum,
said maximum thickness (T) being defined as being measured in a direction perpendicular to said straight reference plane (R).
A voice prosthesis according to claim 8, wherein said flatness ratio of the voice prosthesis (1) is at least 2.5.
A voice prosthesis according to claim 9, wherein said flatness ratio of the voice prosthesis (1) is at least 3.0.
A voice prosthesis according to any one of the preceding claims, wherein the at least one speech intention detector (5, 6, 7) comprises at least one optical sensor (5, 6, 7) for detecting, during said intra-oral use of the voice prosthesis (1) by a human (2), a condition in which the human opens his or her mouth indicative of the intention of the human to speak.
A voice prosthesis according to any one of the preceding claims, further comprising at least one intra-oral use detector (9) for detecting a condition indicative of whether the voice prosthesis (1) is in intra-oral use.
A voice prosthesis according to claim 12, wherein the at least one intra-oral use detector (9) comprises at least one electric conductivity sensor (9).
A voice prosthesis according to any one of the preceding claims, further comprising at least one orientation detector (10) for detecting, during said intra-oral use of the voice prosthesis (1) by a human (2), a change in orientation of the head of the human (2).
A voice prosthesis according to any one of the preceding claims, wherein the voice prosthesis (1) is packed in a blister pack.