U.S. patent application number 10/660283 was filed with the patent office on 2004-07-08 for implantable medical devices with multiple transducers.
This patent application is currently assigned to Vibrant Med-El Hearing Technology GmbH. Invention is credited to Ball, Geoffrey, Schmidt, Marcus.
Application Number | 20040133250 10/660283 |
Document ID | / |
Family ID | 31997817 |
Filed Date | 2004-07-08 |
United States Patent
Application |
20040133250 |
Kind Code |
A1 |
Ball, Geoffrey ; et
al. |
July 8, 2004 |
Implantable medical devices with multiple transducers
Abstract
The present invention relates to implantable medical devices for
improving sound perception by individuals with severe to profound
hearing loss or tinnitus. In particular, the present invention
provides methods and devices for stimulating structures of the ear
via multiple signal transducers.
Inventors: |
Ball, Geoffrey; (Axams,
AT) ; Schmidt, Marcus; (Innsbruck, AT) |
Correspondence
Address: |
Christine A. Lekutis
MEDLEN & CARROLL, LLP
Suite 350
101 Howard Street
San Francisco
CA
94105
US
|
Assignee: |
Vibrant Med-El Hearing Technology
GmbH
|
Family ID: |
31997817 |
Appl. No.: |
10/660283 |
Filed: |
September 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60409394 |
Sep 10, 2002 |
|
|
|
Current U.S.
Class: |
607/57 |
Current CPC
Class: |
A61N 1/36038 20170801;
H04R 25/606 20130101; A61N 1/0541 20130101; A61N 1/36036
20170801 |
Class at
Publication: |
607/057 |
International
Class: |
A61N 001/18 |
Claims
We claim:
1. A device for improving hearing in a subject, comprising: a) a
transducer comprising a magnet and a coil disposed within and
attached to a housing, said magnet producing a first magnetic field
and said coil producing a second magnetic field, said first and
second magnetic fields interacting to cause vibrations of said
housing, b) at least one electrode, c) a receiver, d) a means for
conducting current between said receiver and said transducer, and
e) a means for conducting current between said receiver and said at
least one electrode.
2. The device of claim 1, wherein said transducer is a floating
mass transducer.
3. The device of claim 1, wherein said transducer is configured for
attachment to a subject's temporal bone.
4. The device of claim 1, wherein said transducer is configured for
attachment to a bone of a subject's ossicular chain.
5. The device of claim 1, wherein said transducer is configured for
attachment to a subject's round window.
6. The device of claim 1, wherein said at least one electrode is
configured for attachment to a subject's round window.
7. The device of claim 1, wherein said at least one electrode is
configured for attachment to an outer surface of a subject's round
window.
8. The device of claim 1, wherein said at least one electrode
comprises a microelectrode array configured for insertion within a
subject's cochlea.
9. The device of claim 1, wherein said receiver is configured for
implantation within a subject's mastoid bone.
10. The device of claim 1, further comprising an audio processor
comprising: a microphone, a circuit, a battery, and a coil,
disposed within and attached to a housing.
11. A device for improving hearing in a subject, comprising: a
microphone, a battery, electronics, at least one electrical
transducer suitable for transmission of an electric signal to a
structure of a subject's inner ear, and at least one mechanical
transducer suitable for transmission of a mechanical signal to a
structure of a subject's middle ear.
12. The device of claim 11, wherein said microphone is disposed
within and attached to a microphone housing and wherein leads
extend from said microphone to a position outside said microphone
housing.
13. The device of claim 11, wherein said microphone is selected
from the group consisting of an omnidirectional microphone and a
bidirectional microphone.
14. The device of claim 11, wherein a protective cover is attached
to said microphone.
15. The device of claim 11, further comprising an amplifier.
16. The device of claim 11, wherein said battery is disposed within
and attached to a battery housing and wherein leads extend from
said battery to a position outside of said battery housing.
17. The device of claim 11, further comprising a means to signal
low charge state of said battery.
18. The device of claim 11, further comprising an external charge
unit comprising a battery status indicator for detecting the charge
state of said battery.
19. The device of claim 11, wherein said electronics are disposed
within and attached to an electronics housing.
20. The device of claim 11, wherein said electronics comprise a
telemetry block and a communications block.
21. The device of claim 20, wherein said telemetry block is
selected from the group consisting of a bidirectional telemetry
block and a unidirectional telemetry block.
22. The device of claim 20, wherein said telemetry block and said
communications block comprise a dual coil.
23. The device of claim 20, wherein said telemetry block and said
communications block comprise at least two resonant coils.
24. The device of claim 23, further comprising a magnet to
facilitate alignment of said at least two resonant coils.
25. The device of claim 23, wherein an alternating current signal
is transmitted between said at least two resonant coils.
26. The device of claim 23, wherein an amplitude modulated signal
is transmitted between said at least two resonant coils.
27. The device of claim 23, wherein a base band signal is
transmitted between said at least two resonant coils.
28. The device of claim 23, wherein an alternating current signal
in the audio frequency band is transmitted between said at least
two resonant coils.
29. The device of claim 23, wherein an alternating current signal
above 20,000 hertz is transmitted between said at least two
resonant coils.
30. The device of claim 11, wherein said microphone, said power
supply, and said electronics, are attached to and disposed within a
combined housing, and wherein said at least one electrical
transducer and said at least one mechanical transducer are located
external to said combined housing.
31. The device of claim 30, wherein said combined housing is
selected from the group consisting of a ceramic housing and a
titanium housing.
32. The device of claim 30, wherein said combined housing is
suitable for surgical implantation in a subject's mastoid bone.
33. The device of claim 11, wherein said mechanical transducer has
a resonant frequency between 250 and 10,000 hertz.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to implantable medical devices
for improving sound perception by individuals with severe to
profound hearing loss or tinnitus. In particular, the present
invention provides methods and devices for stimulating structures
of the ear via multiple signal transducers.
BACKGROUND OF THE INVENTION
[0002] Hearing impairment can be characterized according to its
physiological source. There are two general categories of hearing
impairment, conductive and sensorineural, although sometimes a
combination of both may arise (mixed). Conductive hearing
impairment results from diseases or disorders that limit the
transmission of sound through the outer and/or middle ear.
Conductive hearing impairment is often treated surgically with an
implanted prosthesis to replace part or all of the ossicles.
Sensorineural hearing impairment occurs in the inner ear and/or
neural pathways and accounts for the vast majority of hearing
impairment. In patients with sensorineural hearing impairment, the
external and middle ear function normally. The sound vibrations are
transmitted undisturbed through the eardrum and ossicles where
fluid waves are created in the cochlea. However, because some of
the delicate sensory hair cells inside the cochlea have degenerated
or been damaged, the inner ear cannot detect the full intensity and
quality of the sound. Acquired sensorineural hearing loss can occur
as a result of aging or exposure to loud noise over a protracted
period of time.
[0003] Hearing loss is quantified as borderline or slight, mild,
moderate, severe, and profound, according to the volume of sounds
that can be heard without amplification. Individuals with severe
hearing loss are unable to hear sound below 70 dB and individuals
with profound hearing loss are unable to hear sound below 91 dB. In
practical terms, a person with severe hearing loss is incapable of
hearing sounds softer than that of a busy street, while a person
with profound hearing loss is incapable of hearing sounds softer
than that of a subway. Without any type of assistance, normal
conversation is not heard by individuals in either group. Over half
a million Americans are suffering from severe to profound hearing
loss (Mohr et al., 2000, Int. J. Technol. Assess Health Care,
16:1120-1135).
[0004] Tinnitus or ringing in the ears is another frequently
debilitating auditory problem characterized by the perception of
ringing, hissing, or other sound in the ears or head when no
external sound is present. About 12 million Americans have severe
enough tinnitus to seek medical attention, and about two million of
these are seriously incapacitated by this condition. Untreated
hearing impairments result in lost productivity, and increased
medical and educational expenditures. Thus, apart from consequences
to the individual, hearing loss is costly to society.
[0005] Traditional approaches to the management of sensorineural
hearing impairment and tinnitus involve the use of hearing aids or
cochlear implants. Hearing aids are commonly used to manage the
mild to severe sensorineural hearing-impaired population. Cochlear
implants are indicated for individuals with severe to profound
hearing loss. Hearing aids are devices that acoustically amplify
sound to increase the movement of the tympanic membrane and
indirectly vibrate the ossicles. Cochlear implants electronically
stimulate the inner ear through a series of electrodes implanted in
the cochlea during a surgical procedure.
[0006] However, stimulation of structures of the ear only
acoustically or electronically, is not sufficient to provide
optimal hearing correction and is frequently accompanied by
undesirable side effects. For instance, traditional hearing aids
provide limited hearing assistance in the high frequency range,
whereas, cochlear implants provide limited hearing assistance in
the low frequency range. In addition, traditional hearing aids do
not always produce clear natural sounds, and cochlear implants do
not always correct and may even aggravate tinnitus.
[0007] Thus, there remains a need in the art for medical devices
that provide hearing correction across the entire normal audio
frequency range for individuals with severe to profound hearing
loss or tinnitus. The present invention provides partially and
fully implantable hearing devices that provide suitable stimulation
to structures of the ear resulting in superior hearing
correction.
SUMMARY OF THE INVENTION
[0008] The present invention relates to implantable medical devices
for improving sound perception by individuals with severe to
profound hearing loss or tinnitus. In particular, the present
invention provides methods and devices for stimulating structures
of the ear via multiple signal transducers.
[0009] The present invention provides devices for improving hearing
in a subject, comprising: a transducer comprising a magnet and a
coil disposed within and attached to a housing, the magnet
producing a first magnetic field and the first coil producing a
second magnetic field, the first and second magnetic fields
interacting to cause vibrations of the housing, at least one
electrode, a receiver, a means for conducting current between the
receiver and the transducer, and a means for conducting current
between the receiver and the at least one electrode. In preferred
embodiments, the transducer is a floating mass transducer. In some
embodiments, the transducer is configured for attachment to a
subject's temporal bone. In other embodiments, the transducer is
configured for attachment to a bone of a subject's ossicular chain.
In further embodiments, the transducer is configured for attachment
to a subject's round window. Also provided are embodiments, wherein
the at least one electrode is configured for attachment to a
subject's round window. In other embodiments, the at least one
electrode is configured for attachment to an outer surface of a
subject's round window. In further embodiments, the at least one
electrode comprises a microelectrode array configured for insertion
within a subject's cochlea. Also provided are embodiments, wherein
the receiver is configured for implantation within a subject's
mastoid bone. Some embodiments, the devices for improving hearing
in a subject further comprise an audio processor comprising: a
microphone, a circuit, a battery, and a coil, disposed within and
attached to a housing.
[0010] The present invention also provides methods of improving
hearing in a subject, comprising the steps of: providing a device
comprising: i) a transducer comprising a magnet and a coil disposed
within and attached to a housing, the magnet producing a first
magnetic field and the first coil producing a second magnetic
field, the first and second magnetic fields interacting to cause
vibrations of the housing, ii) at least one electrode, iii) a
receiver, and iv) a first pair of leads and a second pair of leads;
surgically implanting the transducer in the middle ear of a
subject, the at least one electrode in the inner ear of the subject
and the receiver external to the middle ear; and conducting current
from the receiver to the implanted transducer through the first
pair of leads so as to cause the housing to vibrate, and conducting
current from the receiver to the at least one implanted electrode
through the second pair of leads, so as to transmit electrons to a
structure of the inner ear. In some embodiments, the hearing
impaired subject is selected from the group consisting of a subject
with severe to profound hearing loss and a subject with tinnitus.
In some preferred embodiments, the hearing impaired subject is
capable of hearing sounds louder than 60 decibels at some but not
all frequencies in the audible frequency range. Also provided are
embodiments, wherein the surgically implanting comprises: creating
a channel in the temporal bone of the subject; inserting the
transducer through the channel into the middle ear; and inserting
the at least one electrode through the channel into the inner ear.
In some preferred embodiments, the surgically implanting further
comprises securing the housing to an ossicle in the middle ear. In
some embodiments, the surgically implanting further comprises
securing the at least one electrode to the round window in the
inner ear. In other embodiments, the surgically implanting further
comprises securing the at least one electrode to an outer surface
of the cochlea in the inner ear. In still further embodiments, the
surgically implanting further comprises insertion of the at least
one electrode within the cochlea in the inner ear. In some
preferred embodiments, the surgically implanting further comprises
replacement of the cochlear fluid. Also provided are embodiments,
wherein the surgically implanting further comprises shaping a
concave portion of the mastoid and subcutaneously placing the
receiver in the concave portion.
[0011] Moreover, the present invention provides devices for
improving hearing in a subject, comprising: a microphone, a
battery, electronics, at least one electrical transducer suitable
for transmission of an electric signal to a structure of a
subject's inner ear, and at least one mechanical transducer
suitable for transmission of a mechanical signal to a structure of
a subject's middle ear. In some devices, the electronics comprise
signal processing electronics, charging electronics, and system
management electronics. In some embodiments, the microphone is
disposed within and attached to a microphone housing and wherein
leads extend from the microphone to a position outside the
microphone housing. In further embodiments, the microphone is
selected from the group consisting of an omnidirectional microphone
and a bidirectional microphone. In some preferred embodiments, a
protective cover is attached to the microphone, while in
particularly preferred embodiments, the device further comprising
an amplifier. Additionally, devices are provided wherein the
battery is disposed within and attached to a battery housing and
wherein leads extend from the battery to a position outside of the
battery housing. In some embodiments, the device further comprises
a means to signal low charge state of the battery. In other
embodiments, the device further comprises external charge unit
comprising a battery status indicator for detecting the charge
state of the battery. Moreover, devices are provided wherein the
electronics are disposed within and attached to an electronics
housing. In preferred embodiments, the electronics comprise a
telemetry block and a communications block. In some embodiments,
the telemetry block is selected from the group consisting of a
bidirectional telemetry block and a unidirectional telemetry block.
Also provided are devices wherein the telemetry block and the
communications block comprise a dual coil. Alternatively, devices
are provided wherein the telemetry block and the communications
block comprise at least two resonant coils. In some embodiments,
the devices further comprise a magnet to facilitate alignment of
the at least two resonant coils. In preferred embodiments, an
alternating current signal is transmitted between the at least two
resonant coils, an amplitude modulated signal is transmitted
between the at least two resonant coils, or a base band signal is
transmitted between the at least two resonant coils. In some
embodiments, an alternating current signal in the audio frequency
band is transmitted between the at least two resonant coils, while
in other embodiments, an alternating current signal above 20,000
hertz is transmitted between the at least two resonant coils. In
some particularly preferred embodiments, the microphone, the power
supply, and the electronics, are attached to and disposed within a
combined housing, and wherein the at least one electrical
transducer and the at least one mechanical transducer are located
external to the combined housing. In a subset of these embodiments,
the combined housing is selected from the group consisting of a
ceramic housing and a titanium housing. In some preferred
embodiments, the combined housing is suitable for surgical
implantation in a subject's mastoid bone. Also provided are devices
wherein the mechanical transducer has a resonant frequency between
250 and 10,000 hertz.
[0012] Additionally, the present invention provides devices for
improving hearing in a subject, comprising: a microphone, a
battery, electronics, at least one electrical transducer (such as a
cochlear implant) suitable for transmission of an electric signal
to a structure of a subject's inner ear, and at least one
mechanical transducer (such as a floating mass transducer) suitable
for transmission of a mechanical signal to a structure of a
subject's middle ear. Also provided by the present invention are
devices that further comprise a means for storing subject data and
device data. In preferred embodiments, the devices further comprise
at least one set of leads, wherein the leads are selected from the
group consisting of detachable leads and nondetachable leads. In
some devices, the microphone is a directional microphone comprising
at least two input transducers. Also in some devices, the
electronics comprise signal processing electronics, charging
electronics, and system management electronics. In some devices,
the electrical transducer and the mechanical transducer comprise
physically separate output channels that work along parallel paths.
In other devices the output channels work along the same path in
concert. In some devices the electrical transducer output channel
and the mechanical transducer output channel are activated or
inactivated independently. Also provided are devices where both
transducer output channels are programmed using a universal
external programming device. In some devices, the universal
external programming device permits the programming of the signal
processing and transducer output channels on a single platform. In
preferred embodiments, the mechanical transducer is suitable for
surgical implantation independently from surgical implantation of
at least one of the electrical transducer, the microphone, the
battery and the electronics. In some devices the at least one
electrode is implanted to a depth within the cochlea of 20
millimeters or more, while in other devices the at least one
electrode is implanted to a depth within the cochlea of less than
20 millimeters. Moreover, some devices are suitable for use in
combination with an externally located FM audio broadcast
system.
DESCRIPTION OF THE FIGURES
[0013] FIG. 1 shows pre and post medical implant audiograms for two
hypothetical patients. Panels A and B provide pre and post
audiograms for a patient with residual hearing in the low frequency
range. Panels C and D provide pre and post audiograms for a patient
with residual hearing in the high frequency range.
[0014] FIG. 2, Panels A, B and C, show several embodiments of a
dual mode hearing device comprising mechanical stimulation in the
form of a floating mass transducer positioned on the ossicular
chain, and electric stimulation in the form of electrodes placed in
or on the cochlea (e.g., cochlear implant) or round window.
[0015] FIG. 3 shows two embodiments of a dual mode hearing device
comprising juxtaposed floating mass transducer and electrode(s). In
Panel A, the stimulation means of the hearing device are implanted
in the middle ear (e.g., the electrode is adjacent to the floating
mass transducer housing which is attached to the surface of the
round window). In Panel B, the stimulation means of the hearing
device are implanted in the inner ear (e.g., the floating mass
transducer is connected in series to several electrodes implanted
in the cochlea).
[0016] FIG. 4, Panels A, B, and C, show several embodiments of the
hearing device including both two and three stimulation modes
(e.g., ultrasonic, mechanical, and electrical).
DESCRIPTION OF THE INVENTION
[0017] The present invention relates to implantable medical devices
for improving sound perception by individuals with severe to
profound hearing loss or tinnitus. In particular, the present
invention provides methods and devices for stimulating structures
of the ear via multiple signal transducers.
[0018] Treatment Population
[0019] The present invention provides implantable hearing devices
comprising at least two transducers to provide hearing correction
across the entire normal audio frequency range for individuals with
severe or profound hearing loss or tinnitus. Individuals with
residual hearing over one frequency range (e.g., 10-30 dB of useful
dynamic range), but no or little hearing over a second frequency
range are particularly good candidates for the hearing devices
disclosed herein. Additionally, patients who have rejected standard
cochlear implants due to medical or performance issues are
anticipated to receive benefit from the multi-transducer hearing
devices of the present invention.
[0020] In one embodiment, a floating mass transducer is used to
provide hearing correction in the residual hearing frequency range,
and a cochlear implant is used to provide hearing correction in the
non-hearing frequency range. As shown in FIG. 1, Panel A, an
individual with residual hearing in the low frequency range
receives mechanical stimulation in the low frequency range and
electrical stimulation in the high frequency range. Conversely, as
shown in FIG. 1, Panel B, an individual with residual hearing in
the high frequency range receives mechanical stimulation in the
high frequency range and electronic stimulation in the low
frequency range. For both patients, some frequencies receive
mechanical as well as electronic stimulation.
[0021] Stimulation Modes
[0022] Mechanical stimulation is provided by the audio and/or
ultrasonic floating mass transducer (FMT) component(s) of the
hearing device. Briefly, the FMT is a transducer with a mass that
vibrates in direct response to an external signal which corresponds
to sound waves. The mass is mechanically coupled to a housing which
is mountable on a vibratory structure of the ear. Thus, the
mechanical vibration of the floating mass is transformed into a
vibration of the vibratory structure of the ear (e.g., tympanic
membrane, malleus, incus, and stapes, oval window, round window,
and cochlea). Each of the vibratory structures of the ear vibrates
to some degree when a person with normal hearing hears sound waves.
However, hearing loss in a person may be evidenced by one or more
vibratory structures vibrating less than normal or not at all. FMTs
suitable for use as components of the present invention include but
are not limited to those disclosed in U.S. Pat. No. 6,190,305,
hereby incorporated by reference in its entirety.
[0023] Electric stimulation is provided by the coclear implant (CI)
component of the hearing device. Briefly, the CI delivers electric
signals to the cochlea which correspond to ambient sounds. As the
cochlea is naturally partitioned into regions responsive to signals
in a particular frequency range, an electrode array with a
plurality of electrodes is utilized to deliver a cochlea
stimulating signal within a preselected frequency range to the
appropriate region. The electrical currents and electric fields
from each electrode, which may be active simultaneously, stimulate
the auditory nerve cells disposed in the modiolus of the cochlea.
CIs suitable for use as components of the present invention include
but are not limited to those disclosed in U.S. Pat. No. 6,421,569,
incorporated herein.
[0024] Multiple Mode Devices
[0025] The partially and totally implantable hearing devices of the
present invention take a wide variety of forms. In one embodiment
as shown in FIG. 2 Panel A, a floating mass transducer is placed on
the ossicular chain and an electrode is placed on the round window.
The floating mass transducer imparts vibratory motion to the ear,
while the electrode stimulates the cochlea electrically. In another
embodiment as shown in FIG. 2 Panel B, a floating mass transducer
is placed on the ossicular chain and multiple electrodes are placed
at different locations around the outside of the cochlea. In a
further embodiment as shown in FIG. 2 Panel C, a multi-channel
electrode is used in combination with a floating mass transducer
and either a means for preventing drainage of the cochlear fluid or
a means for replacement of the cochlear fluid. Alternatively, both
the floating mass transducer and the electrode are placed together
on the round window (See, e.g., FIG. 3 Panel A, device comprising a
floating mass transducer with an electrode on the surface facing
the round window). Suitable configurations for implantation in the
inner ear for stimulation of the cochlear fluid comprise either a
floating mass transducer connected to an electrode array, or an
electrode connected to multiple floating mass transducers (See,
e.g., FIG. 3 Panel B).
[0026] As shown in FIG. 4 Panel A, some embodiments of the
implantable hearing devices of the present invention provide
mechanical stimulation in the form of both an ultrasonic floating
mass transducer, and an audio floating mass transducer in addition
to electric stimulation. In this way, a single implant provides
multiple stimulation modes for patients with especially troublesome
hearing loss.
[0027] Definitions
[0028] To facilitate an understanding of the present invention, a
number of terms and phrases are defined below:
[0029] As used herein, the term "subject" refers to a human or
other animal. It is intended that the term encompass patients, such
as hearing impaired patients.
[0030] The terms "hearing impaired subject" and "hearing impaired
patient" refer to animals or persons with any degree of loss of
hearing that has an impact on the activities of daily living or
that requires special assistance or intervention. Subjects with
severe (sound detection above 70 dB) to profound (sound detection
above 90 dB) hearing loss are preferred candidates for the hearing
devices of the present invention. Subjects with severe "tinnitus"
or "ringing in the ears" are also expected to receive benefit from
the hearing devices disclosed herein.
[0031] As used herein, the terms "external ear canal" and "external
auditory meatus" refer to the opening in the skull through which
sound reaches the middle ear. The external ear canal extends to the
tympanic membrane (or "eardrum"), although the tympanic membrane
itself is considered to be part of the middle ear. The external ear
canal is lined with skin and due to its resonant characteristics,
provides some amplification of sound traveling through the canal.
The "outer ear" includes those parts of the ear that are normally
visible (e.g., the auricle or pinna, and the surface portions of
the external ear canal).
[0032] As used herein, the term "middle ear" refers to the portion
of the auditory system that is internal to the tympanic membrane,
and including the tympanic membrane, itself. It includes the
auditory ossicles (i.e., malleus, incus, and stapes, commonly known
as the hammer, anvil, and stirrup) that from a bony chain (e.g.,
ossicular chain) across the middle ear chamber to conduct and
amplify sound waves from the tympanic membrane to the oval window.
The ossicles are secured to the walls of the chamber by ligaments.
The middle ear is open to the outside environment by means of the
eustachian tube.
[0033] As used herein, the term "inner ear" refers to the
fluid-filled portion of the ear. Waves relayed by the ossicles to
the oval window are created in the fluid, pass through the cochlea,
and stimulate the delicate hair-like endings of the receptor cells
of the auditory nerve. These receptors generate electrochemical
signals which are interpreted by the brain as sound.
[0034] The term "cochlea" refers to the part of the inner ear that
is concerned with hearing. The cochlea is a division of the bony
labyrinth located anterior to the vestibule, coiled into the form
of a snail shell, and consisting of a spiral canal in the petrous
part of the temporal bone.
[0035] As used herein, the term "cochlear hair cell" refers to the
sound sensing cell of the inner ear, which have modified ciliary
structures (e.g., hairs), that enable them to produce an electrical
(neural) response to mechanical motion caused by the effect of
sound waves on the cochlea. Frequency is detected by the position
of the cell in the cochlea and amplitude by the magnitude of the
disturbance.
[0036] The term "cochlear fluid" refers to the liquid within the
cochlea which transmits vibrations to the hair cells.
[0037] The terms "round window" and "fenestra of the cochlea" refer
to an opening in the medial wall of the middle ear leading into the
cochlea.
[0038] The term "temporal bone" refers to a large irregular bone
situated in the base and side of the skull, consisting of the,
squamous, tympanic and petrous. The term "mastoid" refers to the
process of the temporal bone behind the ear.
[0039] As used herein, the term "amplifier" refers to a device that
produces an electrical output that is a function of the
corresponding electrical input parameter, and increases the
magnitude of the input by means of energy drawn from an external
source (i.e., it introduces gain). "Amplification" refers to the
reproduction of an electrical signal by an electronic device,
usually at an increased intensity. "Amplification means" refers to
the use of an amplifier to amplify a signal. It is intended that
the amplification means also includes means to process and/or
filter the signal.
[0040] As used herein, the term "receiver" refers to the part of a
system that converts transmitted waves into a desired form of
output. The range of frequencies over which a receiver operates
with a selected performance (i.e., a known level of sensitivity) is
the "bandwidth" of the receiver. The "minimal discernible signal"
is the smallest value of input power that results in output by the
receiver.
[0041] As used herein, the term "transmitter" refers to a device,
circuit, or apparatus of a system that is used to transmit an
electrical signal to the receiving part of the system. A
"transmitter coil" is a device that receives an electrical signal
and broadcasts it to a "receiver coil." It is intended that
transmitter and receiver coils may be used in conjunction with
centering magnets which function to maintain the placement of the
coils in a particular position and/or location.
[0042] As used herein, the terms "speaker" and "loudspeaker" refer
to electroacoustic devices that convert electrical energy into
sound energy. The speaker is the final unit in any sound reproducer
or acoustic circuit of any broadcast receiver. It is not intended
that the present invention be limited to any particular type of
speaker. For example, the term encompasses loudspeakers including
but not limited to magnetic, cone, horn, crystal,
magnetorestriction, magnetic-armature, electrostatic, and labyrinth
speakers. It is also intended that multiple speakers of the same or
different configurations will be used in the present invention.
[0043] As used herein, the term "microphone" refers to a device
that converts sound energy into electrical energy. It is the
converse of the loudspeaker, although in some devices, the
speaker-microphone may be used for both purposes (i.e., a
loudspeaker microphone). Various types of microphones are
encompassed by this definition, including carbon, capacitor,
crystal, moving-coil, and ribbon embodiments. Most microphones
operate by converting sound waves into mechanical vibrations that
then produce electrical energy. The force exerted by the sound is
usually proportional to the sound pressure. In some embodiments, a
thin diaphragm is mechanically coupled to a suitable device (e.g.,
a coil). In alternative embodiments the sound pressure is converted
to electrical pressure by direct deformation of suitable
magnetorestrictive or piezoelectric crystals (e.g.,
magnetorestriction and crystal microphones).
[0044] The term "circuit" as used herein, refers to the complete
path of an electric current.
[0045] As used herein, the term "transducer" refers to any device
that converts a non-electrical parameter (e.g., sound, pressure or
light), into electrical signals or vice versa. Microphones are one
type of electroacoustic transducer.
[0046] As used herein, the term "resistor" refers to an electronic
device that possesses resistance and is selected for this use. It
is intended that the term encompass all types of resistors,
including but not limited to, fixed-value or adjustable, carbon,
wire-wound, and film resistors. The term "resistance" (R; ohm)
refers to the tendency of a material to resist the passage of an
electric current, and to convert electrical energy into heat
energy.
[0047] The term "magnet" refers to a body (e.g., iron, steel or
alloy) having the property of attracting iron and producing a
magnetic field external to itself, and when freely suspended, of
pointing to the poles.
[0048] As used herein, the term "magnetic field" refers to the area
surrounding a magnet in which magnetic forces may be detected.
[0049] The term "vibrations" refer to limited reciprocating motions
of a particle of an elastic body or medium in alternately opposite
directions from its position of equilibrium, when that equilibrium
has been disturbed.
[0050] The term "coil" refers to an object made of wire wound in a
spiral configuration, used in electronic applications.
[0051] As used herein, the term "electrode" refers to a conductor
used to establish electrical contact with a nonmetallic part of a
circuit. In preferred embodiments, the term "electrode" refers to a
conductor used to impart an electric current into a structure of
the ear (e.g., round window, cochlea, etc.). The term
"microelectrode array" refers to an ordered set of electrodes with
extremely small tips, used to stimulate bioelectric potentials of
single cells.
[0052] The term "leads" refers to wires covered with an insulator
used for conducting current between device components (e.g.,
receiver to transducer or receiver to electrode microarray).
[0053] As used herein, the terms "floating mass transducer" and
"FMT.TM." refer to a transducer with a mass that vibrates in direct
response to an external signal which corresponds to sound waves.
The mass is mechanically coupled to a housing which is mountable on
a vibratory structure of the ear. Thus, the mechanical vibration of
the floating mass is transformed into a vibration of the vibratory
structure allowing the patient to hear. A floating mass transducer
can also be utilized as a transducer to transform mechanical
vibrations into electrical signals.
[0054] As used herein, the term "soundbridge" refers to medical
prostheses that serve to improve the hearing of individuals.
Although it is not intended that the present invention be so
limited, in particularly preferred embodiments, soundbridges are
used to improve the hearing of individuals with sensorineural,
conductive (i.e., the ossicular connection is broken, loose, stuck,
or missing), or mixed sensorineural and conductive hearing loss.
Unlike hearing aids that take a sound and make it louder as it
enters the middle ear, in particularly preferred embodiments,
soundbridges convert acoustic sound to vibrations inside the middle
ear. These vibrations are amplified by device electronics in order
to make the vibrations stronger than the patient would normally
achieve with sound transmitted through the ear canal and across the
eardrum. Since in the most preferred embodiments no portion of the
soundbridge is present in the ear canal, problems commonly
experienced with hearing aids (e.g., occlusion, discomfort,
irritation, soreness, feedback, external ear infections, etc.), are
eliminated or reduced.
[0055] In highly preferred embodiments, the soundbridge is divided
into two components, with the external portion comprising an audio
processor (e.g., comprised of a microphone, battery, and the
electronics needed to convert sound to a signal that can be
transmitted to the internal portion of the soundbridge) and the
internal portion comprising an internal receiving link and a
floating mass transducer (FMT.TM.). The audio processor is
positioned on the wearer's head with a magnet. A signal from the
audio processor is transmitted across the skin to an internal
receiver, which then relays the signal via a conductor link to the
FMT.TM.. In turn, the FMT.TM. converts the signal to vibrations
that move the bones of the middle ear in a manner similar to the
way in which sounds move them. Thus, ambient sounds (e.g., voices,
etc.) are picked up by the microphone in the audio processor and
converted to an electrical signal within the audio processor. This
electrical signal is then transmitted across the skin to the
internal receiver which then conveys the signal to the FMT.TM. via
a conducting link, resulting in mechanical vibration of the
ossicles, which are then interpreted by the wearer.
[0056] As used herein, the term "battery" refers to a cell that
furnishes electric current to the hearing devices of the present
invention. In preferred embodiments of the present invention,
"rechargeable" batteries are used.
[0057] In other preferred embodiments, the present invention
provides a completely implantable system in which the microphone,
battery, and electronics are positioned under the patient's skin.
In such embodiments, the battery is positioned and designed so as
to allow recharging while the battery is implanted (i.e., the
battery is recharged while it is in position in situ).
[0058] The term "housing" refers to the structure encasing or
enclosing at least one component (e.g., microphone, battery,
electronics, transducer, etc.) of the devices of the present
invention. In preferred embodiments, the "housing" is produced from
a "biocompatible" material. In particularly preferred embodiments,
the housing comprises at least one hermetic feedthrough through
which leads extend from the component inside the housing to a
position outside the housing.
[0059] As used herein, the term "biocompatible" refers to any
substance or compound that has minimal (i.e., no significant
difference is seen compared to a control) to no irritant or
immunological effect on the surrounding tissue. It is also intended
that the term be applied in reference to the substances or
compounds utilized in order to minimize or to avoid an immunologic
reaction to the housing or other aspects of the invention.
Particularly preferred biocompatible materials include, but are not
limited to titanium, gold, platinum, sapphire, and ceramics.
[0060] As used herein, the term "implantable" refers to any device
that may be surgically implanted in a patient. It is intended that
the term encompass various types of implants. In preferred
embodiments, the device may be implanted under the skin (i.e.,
subcutaneous), or placed at any other location suited for the use
of the device (e.g., within temporal bone, middle ear or inner
ear). An implanted device is one that has been implanted within a
subject, while a device that is "external" to the subject is not
implanted within the subject (i.e., the device is located
externally to the subject's skin). Similarly, the term "surgically
implanting" refers to the medical procedure whereby the hearing
device is placed within a living body.
[0061] As used herein, the term "hermetically sealed" refers to a
device or object that is sealed in a manner that liquids or gases
located outside the device are prevented from entering the interior
of the device, to at least some degree. "Completely hermetically
sealed" refers to a device or object that is sealed in a manner
such that no detectable liquid or gas located outside the device
enters the interior of the device. It is intended that the sealing
be accomplished by a variety of means, including but not limited to
mechanical, glue or sealants, etc. In particularly preferred
embodiments, the hermetically sealed device is made so that it is
completely leak-proof (i.e., no liquid or gas is allowed to enter
the interior of the device at all).
[0062] As used herein, the term "reproduction of sound" refers to
the reproduction of sound information from an audiofrequency source
of electrical signals. It is intended that the term encompass
complete sound reproduction systems (i.e., comprising the original
source of audio information, preamplifier, and control circuits,
audiofrequency power amplifiers and loudspeaker[s]). It is intended
that the term encompass monophonic, as well as stereophonic sound
reproduction, including stereophonic broadcast transmission. In
some embodiments, a sound reproduction system composed of
high-quality components, and which reproduces the original audio
information faithfully and with very low noise levels, is referred
to as a "high-fidelity" system (hi-fi). As used herein, the term
"audio processor" refers to any device or component that processes
sound for any purpose.
[0063] As used herein, the term "acoustic wave" and "sound wave"
refer to a wave that is transmitted through a solid, liquid, and/or
gaseous material as a result of the mechanical vibrations of the
particles forming the material. The normal mode of wave propagation
is longitudinal (i.e., the direction of motion of the particles is
parallel to the direction of wave propagation), the wave therefore
consists of compressions and rarefactions of the material. It is
intended that the present invention encompass waves with various
frequencies, although waves falling within the audible range of the
human ear (e.g., approximately 20 Hz to 20 kHz) are particularly
preferred. Waves with frequencies greater than approximately 20 kHz
are "ultrasonic" waves.
[0064] As used herein, the term "frequency" (v or f) refers to the
number of complete cycles of a periodic quantity occurring in a
unit of time. The unit of frequency is the "hertz," corresponding
to the frequency of a periodic phenomenon that has a period of one
second. Table 1 below lists various ranges of frequencies that form
part of a larger continuous series of frequencies. Internationally
agreed radiofrequency bands are shown in this table. Microwave
frequencies ranging from VHF to EHF bands (i.e., 0.225 to 100 GHz)
are usually subdivided into bands designated by the letters, P, L,
S, X, K, Q, V, and W.
1TABLE 1 Radiofrequency Bands Frequency Band Wavelength 300 to 30
GHz Extremely High Frequency (EHF) 1 mm to 1 cm 30 to 3 GHz
Superhigh Frequency (SHF) 1 cm to 10 cm 3 to 0.3 GHz Ultrahigh
Frequency (UHF) 10 cm to 1 m 300 to 30 MHz Very High Frequency
(VHF) 1 m to 10 m 30 to 3 MHz High Frequency (HF) 10 m to 100 m 3
to 0.3 MHz Medium Frequency (MF) 100 m to 1000 m 300 to 30 kHz Low
Frequency (LF) 1 km to 10 km 30 to 3 kHz Very Low Frequency (VLF)
10 km to 100 km
[0065] As used herein, the term "gain," measured in decibels, is
used as a measure of the ability of an electronic circuit, device,
or apparatus to increase the magnitude of a given electrical input
parameter. In a power amplifier, the gain is the ratio of the power
output to the power input of the amplifier. "Gain control" (or
"volume control") is a circuit or device that varies the amplitude
of the output signal from an amplifier.
[0066] As used herein, the term "decibel" (dB) is a dimensionless
unit used to express the ratio of two powers, voltages, currents,
or sound intensities. It is 10.times. the common logarithm of the
power ratio. If two power values (P1 and P2) differ by n decibels,
then n=10 log.sub.10(P2/P1), or P2/P1=10.sup.n/10. If P1 and P2 are
the input and output powers, respectively, of an electric network,
if n is positive (i.e., P2>P1), there is a gain in power. If n
is negative (i.e., P1>P2), there is a power loss.
[0067] As used herein, the terms "carrier wave" and "carrier" refer
to a wave that is intended to be modulated by a signal that is to
be transmitted. The process of modulation produces spectral
components termed "sidebands" that fall into frequency bands at
either the upper ("upper sideband") or lower ("lower sideband")
side of the carrier frequency. A sideband in which some of the
spectral components are greatly attenuated is referred to a
"vestigial sideband." Generally, these components correspond to the
highest frequency in the modulating signals. A single frequency in
a sideband is referred to as a "side frequency," while the
"baseband" is the frequency band occupied by all of the transmitted
modulating signals.
[0068] The term "modulation" is used in general reference, to the
alteration or modification of any electronic parameter by another.
For example, it encompasses the process by which certain
characteristics of one wave (the "carrier wave" or "carrier
signal") are modulated or modified in accordance with the
characteristic of another wave (the "modulating wave"). The reverse
process is "demodulation," in which an output wave is obtained that
has the characteristics of the original modulating wave or signal.
Characteristics of the carrier that may be modulated include the
amplitude, and phase angle. Modulation by an undesirable signal is
referred to as "cross modulation," while "multiple modulation" is a
succession of processes of modulation in which the whole, or part
of the modulated wave from one process becomes the modulating wave
for the next.
[0069] As used herein, the term "demodulator" ("detector") refers
to a circuit, apparatus, or circuit element that demodulates the
received signal (i.e., extracts the signal from a carrier, with
minimum distortion). "A modulator" is any device that effects
modulation.
[0070] As used herein, the term "dielectric" refers to a solid,
liquid, or gaseous material that can sustain an electric field and
act as an insulator (i.e., a material that is used to prevent the
loss of electric charge or current from a conductor, insulators
have a very high resistance to electric current, so that the
current flow through the material is usually negligible).
[0071] As used herein, the term "electronic device" refers to a
device or object that utilizes the properties of electrons or ions
moving in a vacuum, gas, or semiconductor. "Electronic circuitry"
refers to the path of electron or ion movement, as well as the
direction provided by the device or object to the electrons or
ions. A "circuit" or "electronics package" is a combination of a
number of electrical devices and conductors that when connected
together, form a conducting path to fulfill a desired function,
such as amplification, filtering, or oscillation. Any constituent
part of the circuit other than the interconnections is referred to
as a "circuit element." A circuit may be comprised of discrete
components, or it may be an "integrated circuit." A circuit is said
to be "closed," when it forms a continuous path for current. It is
contemplated that any number of devices be included within an
electronics package. It is further intended that various components
be included in multiple electronics packages that work
cooperatively to amplify sound. In some embodiments, the "vocal
electronics" package refers to the entire system used to improve
and/or amplify sound production.
[0072] As used herein, the term "electret" refers to a substance
that is permanently electrified, and has oppositely charged
extremities.
[0073] As used herein, the term "reset" refers to the restoration
of an electrical or electronic device or apparatus to its original
state following operation of the equipment.
[0074] As used herein, the term "residual charge" refers to the
portion of a charge stored in a capacitor that is retained when the
capacitor is rapidly discharged, and may be subsequently withdrawn.
Although it is not necessary to understand the mechanism to use the
present invention, and the present invention present invention is
not limited to any particular mechanism of action, it is
hypothesized that this results from viscous movement of the
dielectric under charge causing some of the charge to penetrate the
dielectric and therefore, become relatively remote from the plates;
only the charge near the plates is removed by rapid discharge.
[0075] As used herein, the term "current" refers to the rate of
flow of electricity. The current is usually expressed in amperes;
the symbol used is "I."
[0076] As used herein, the term "residual current" refers to a
current that flows for a short time in the external circuit of an
active electronic device after the power supply to the device has
been turned off. The residual current results from the finite
velocity of the charge carriers passing through the device. The
term "active" is used in reference to any device, component or
circuit that introduces gain or has a directional function. An
"active current," "active component," energy component," "power
component" or "in-phase component of the current" refers to the
component that is in phase with the voltage, alternative current,
and voltage being regarded as vector quantities. The term "passive"
refers to any device, component or circuit that does not introduce
gain, or does not have a directional function. It is intended that
the term encompass pure resistance, capacitance, inductance, or a
combination of these.
[0077] As used herein, the terms "power source" and "power supply"
refer to any source of electrical power in a form that is suitable
for operating electronic circuits. Alternating current power may be
derived either directly or by means of a suitable transformer.
"Alternating current" refers to an electric current whose direction
in the circuit is periodically reversed with a frequency f; that is
independent of the circuit constants. Direct current power may be
supplied from various sources, including, but not limited to
batteries, suitable rectifier/filter circuits, or from a converter.
"Direct current" refers to an unidirectional current of
substantially constant value. The term also encompasses embodiments
that include a "bus" to supply power to several circuits or to
several different points in one circuit. A "power pack" is used in
reference to a device that converts power from an alternating
current or direct current supply, into a form that is suitable for
operating electronic device(s).
[0078] The term "piezoelectric effect" refers to the property of
certain crystalline or ceramic materials to emit electricity when
deformed and to deform when an electric current is passed across
them, a mechanism of interconverting electrical and acoustic
energy; an ultrasound transducer sends and receives acoustic energy
using this effect.
[0079] The term "cochlear implant" refers to an electronic device
implanted under the skin with electrodes in the middle ear on the
promontory or cochlear window or in the inner ear in the cochlea to
create sound sensation in total sensory deafness. A microphone
behind the ear feeds sound waves into a microprocessor carried on
the body, which analyzes the data and sends information back to a
radio transmitter that triggers the electrodes in the middle or
inner ear to produce the appropriate electrical pulses. This does
not enable the patient actually to hear, but rather to distinguish
different sounds according to the neural sensation they
produce.
[0080] As used herein, the term "electronics" refers to a conductor
used to make electrical contact with some part of a circuit.
[0081] The term "ominidirectional microphone" as used herein refers
to a microphone that picks up sound at essentially equal levels in
all directions. The coverage pattern is essentially 360-degrees
with essentially no angle of rejection. In contrast, the term
"bidirectional microphone" refers to a microphone that picks up
sound essentially equally from two directions. This type of
microphone picks up sound from two directions and largely rejects
sound from the sides.
[0082] As used herein, the term "channel" refers to a circuit or
signal path within a piece of equipment. For example, in a mixer it
refers to an input channel (all of the controls and circuitry that
affects a single microphone or line-level device), or an output
channel (all of the controls and circuitry that affects a single
output).
[0083] The term "resonant frequency" as used herein refers to the
frequency at which a piezoelectric ceramic will vibrate most
efficiently (will produce the highest output with the least amount
of voltage applied). The term "resonance" refers to a natural
periodicity, or the reinforcement associated with this
periodicity.
[0084] As used herein the term "block" refers to a number or
quantity of related components dealt with as a single unit.
[0085] The term "signal" refers to an electrical current present on
a wire or in a circuit that represents a soundwave.
[0086] All publications and patents mentioned in the above
specification are herein incorporated by reference. Various
modifications and variations of the described method and system of
the invention will be apparent to those skilled in the art without
departing from the scope and spirit of the invention. Although the
invention has been described in connection with specific preferred
embodiments, it should be understood that the invention as claimed
should not be unduly limited to such specific embodiments. Indeed,
various modifications of the described modes for carrying out the
invention which are obvious to those skilled in the relevant fields
are intended to be within the scope of the following claims.
* * * * *