U.S. patent application number 17/445803 was filed with the patent office on 2021-12-09 for methods for sensing or stimulating activity of tissue.
This patent application is currently assigned to Synchron Australia Pty Limited. The applicant listed for this patent is Synchron Australia Pty Limited. Invention is credited to Thomas James OXLEY.
Application Number | 20210378595 17/445803 |
Document ID | / |
Family ID | 1000005795426 |
Filed Date | 2021-12-09 |
United States Patent
Application |
20210378595 |
Kind Code |
A1 |
OXLEY; Thomas James |
December 9, 2021 |
METHODS FOR SENSING OR STIMULATING ACTIVITY OF TISSUE
Abstract
An intravascular device for placement within an animal vessel,
the intravascular device being adapted to at least one of sense and
stimulate activity of neural tissue located outside the vessel
proximate the intravascular device.
Inventors: |
OXLEY; Thomas James; (New
York, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Synchron Australia Pty Limited |
Melbourne |
|
AU |
|
|
Assignee: |
Synchron Australia Pty
Limited
Melbourne
AU
|
Family ID: |
1000005795426 |
Appl. No.: |
17/445803 |
Filed: |
August 24, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14348863 |
Mar 31, 2014 |
|
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PCT/AU2012/001203 |
Oct 3, 2012 |
|
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17445803 |
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61542822 |
Oct 4, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/056 20130101;
A61N 1/36003 20130101; A61B 5/4076 20130101; A61B 5/6811 20130101;
A61B 5/377 20210101; A61F 2002/5058 20130101; A61B 5/6868 20130101;
A61B 5/686 20130101; A61B 5/4851 20130101; A61B 5/316 20210101;
A61N 1/3756 20130101; A61N 1/0553 20130101; A61B 5/291 20210101;
A61B 5/4836 20130101; A61B 5/4064 20130101; A61B 5/24 20210101;
A61N 1/37252 20130101; A61B 5/6876 20130101; A61B 5/0006 20130101;
A61N 1/36064 20130101; A61B 5/746 20130101; A61F 2/72 20130101;
A61N 1/36067 20130101; A61N 1/3787 20130101; G06F 3/015 20130101;
A61B 5/6862 20130101; A61N 1/36082 20130101; A61B 5/4094 20130101;
A61F 2/54 20130101 |
International
Class: |
A61B 5/00 20060101
A61B005/00; A61N 1/375 20060101 A61N001/375; A61N 1/05 20060101
A61N001/05; A61N 1/36 20060101 A61N001/36; G06F 3/01 20060101
G06F003/01; A61B 5/24 20060101 A61B005/24; A61B 5/377 20060101
A61B005/377; A61F 2/72 20060101 A61F002/72; A61N 1/372 20060101
A61N001/372; A61N 1/378 20060101 A61N001/378 |
Claims
1. (canceled)
2. A method for enabling a patient to control an external device by
performing a mental activity, the method comprising: implanting a
stent structure within a cerebral vessel adjacent to a brain
tissue, the stent structure having a plurality of discrete
electrodes each having an electrode surface, wherein the plurality
of discrete electrodes are configured to sense an electrical
activity of the brain tissue located outside the cerebral vessel;
expanding the stent structure to take a shape of the cerebral
vessel such that expansion of the stent structure brings the
electrode surface of each of the plurality of electrodes into
contact with a wall of the cerebral vessel without expanding or
altering a shape of the electrode surface of each of the plurality
of discrete electrodes, wherein the wall of the cerebral vessel is
adjacent to the brain tissue stimulated by the patient; sensing
electrical activity of the brain tissue using at least one of the
plurality of electrodes after the patient performs the mental
activity; transmitting the electrical activity to an internal unit
which generates a signal that controls the external device, wherein
the electrical activity from the plurality of electrodes conducts
wirelessly to the internal unit, wherein the internal unit is
located exterior to the cerebral vessel; and where the internal
unit is further configured to transmit the signal to the external
device such that the patient controls operation of the external
device by stimulating a region of the brain.
3. The method of claim 2, wherein the plurality of discrete
electrodes is arranged in an array.
4. The method of claim 2, wherein the stent structure comprises a
mesh stent.
5. The method of claim 2, wherein the stent structure comprises a
biodegradable or bioabsorbable substance.
6. The method of claim 2, wherein transmitting the signal from the
internal unit to the external device comprises inductively coupling
the internal unit to an external unit, where the external unit is
mounted externally to the patient.
7. The method of claim 6, further comprising a data transfer
mechanism configured for wireless transfer of data from the
internal unit to the external unit.
8. The method of claim 7, wherein the internal unit comprises a RF
transmitter.
9. The method of claim 7, wherein the external unit comprises a RF
transmitter.
10. The method of claim 2, further comprising positioning a
plurality of additional stent structures each having an array of
electrodes within various regions of one or more cerebral vessels
for sensing electrical activity of multiple additional regions of
brain tissue.
11. The method of claim 2, wherein the external device comprises a
prosthetic limb, wherein transmitting the signal from the internal
unit causes movement of the prosthetic limb.
12. The method of claim 2, wherein the stent structure is
positioned in a second branch or a third branch of a middle
cerebral artery which tracks in or along a post-central gyms of the
brain.
13. The method of claim 2, further comprising sensing changes in
the electrical activity in a pre-central gyrus of the brain tissue
resulting from attempted movement of natural, absent, or artificial
body parts coupled to the patient.
14. The method of claim 2, further comprising transmitting a second
signal from the external device to the internal unit, wherein the
second signal is electrically conducted to the plurality of
discrete electrodes to produce a stimulated electrical activity of
the brain tissue.
15. The method of claim 14, further comprising transmitting the
second signal to the stent structure.
16. The method of claim 2, further comprising a probe coupled to
the stent structure.
17. The method of claim 16, wherein the probe comprises an elongate
flexible micro-tube.
18. The method of claim 2, further comprising a system electrically
coupled to the plurality of electrodes and delivering an alert
using the system when the electrical activity of the brain tissue
falls outside of a predetermined parameter.
19. The method of claim 2, further comprising passing a guide
member into and through the cerebral vessel, the guide member being
adapted for guiding the stent structure to a region within the
cerebral vessel proximate the brain tissue to be sensed.
20. The method of claim 2, further comprising stimulating
electrical activity of the brain tissue from within the cerebral
vessel proximate the brain tissue using the plurality of
electrodes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/348,863 filed Mar. 31, 2014, which is a
U.S. national application filed under 35 U.S.C. 371 of
International Application No. PCT/AU2012/001203 filed Oct. 3, 2012,
which claims benefit of priority to U.S. Provisional Application
No. 61/542,822 filed Oct. 4, 2011, the contents of which are
incorporated by reference herein in their entireties.
TECHNICAL FIELD
[0002] In a particular aspect, the present invention may relate to
intravascularly sensing or stimulating electrical activity of
neural tissue.
BACKGROUND ART
[0003] Any discussion of documents, devices, acts or knowledge in
this specification is included to explain the context of the
invention. It should not be taken as an admission that any of the
material forms a part of the prior art base or the common general
knowledge in the relevant art in Australia or elsewhere on or
before the priority date of the disclosure and broad consistory
statements herein.
[0004] The ability to sense or stimulate nervous tissue in an
animal confers many therapeutic, analytic, and diagnostic
advantages or opportunities, some of which may become apparent on
further reading of this specification.
[0005] Without being an admission of common general knowledge,
current techniques for measuring electrical activity of the brain
involve the use of extra-cranial electrodes placed on the scalp, or
intra-cranial electrodes surgically implanted on the outer cortical
surfaces of the brain, or in the epidural or subdural spaces.
[0006] Unfortunately there are significant disadvantages associated
with these current methods. For example, there may be a lack of
clarity or predisposition to disturbances such as noise or movement
when using extra cranial electrodes applied externally on the
scalp.
[0007] Further, when using intra cranial electrodes, there is a
requirement for invasive surgery to be performed. This carries
considerable risk of complications such as infections or bleeding,
and only provides access for electrode placement on the outer
surfaces of the brain, at least without cutting into and damaging
the brain.
[0008] Relocation of an implanted electrode may be required where
further investigation of a different region of the brain is
desired, or where the signal from the electrode has deteriorated
due to scar formation about the site of implantation. However,
there are also difficulties associated with relocation of
electrodes due to the requirement for further invasive surgery and
possible entrapment of the electrode in scar tissue.
[0009] Current intra cranial electrodes can also require a direct
electrical connection to computer equipment which is located
external to the patient's body.
[0010] Thus, it may be advantageous to provide a new method or
means for sensing or stimulating neuronal cells or neural tissue
which reduces, limits, overcomes, or ameliorates some of the
problems, drawbacks, or disadvantages associated with prior art
devices or methods, or provides an effective alternative to such
devices or methods.
DISCLOSURE OF THE INVENTION
[0011] In one aspect the invention may provide an intravascular
device for placement within an animal vessel, the intravascular
device being adapted to sense or stimulate activity of neural
tissue located outside the vessel proximate the intravascular
device.
[0012] The neural tissue may comprise neuronal cells. The device
may be adapted to sense or stimulate activity of one or more
neuronal cells.
[0013] The intravascular device may comprise a sensor adapted to
sense activity of neural tissue located outside the vessel
proximate the intravascular device.
[0014] The intravascular device may comprise a stimulator adapted
to stimulate activity of neural tissue located outside the vessel
proximate the stimulator.
[0015] Thus, the intravascular device may comprise at least one of
a sensor and a stimulator for respectively sensing or stimulating
activity or neural tissue located outside the vessel proximate the
intravascular device.
[0016] The intravascular device, or sensor or stimulator thereof,
may comprise an electrode. The electrode may be adapted to engage
the wall of the vessel. The electrode may protrude slightly from
the outer surface of the intravascular device.
[0017] The electrode may comprise an inert substance. The inert
substance may comprise platinum or nitinol. The use of an inert
substance may allow deposition of the electrode within the vessel
for several years, or the remainder of the animal's life.
[0018] There may be multiple electrodes. For instance, there may be
a plurality of electrodes arranged in 2 times.4 array.
[0019] The intravascular device, or the sensor thereof, may be
adapted to sense local field potentials from proximate neural
tissue. Additionally, or alternatively, the intravascular device,
or the sensor thereof, may be adapted to sense electrical activity
of a single neuron of the proximate neural tissue. Thus the
intravascular device may be adapted to sense an action potential of
a neuronal cell.
[0020] The intravascular device, or the stimulator thereof, may be
adapted to stimulate a local field potential in proximate neural
tissue. Additionally, or alternatively, the intravascular device,
or stimulator thereof, may be adapted to stimulate electrical
activity of a single neuron of the proximate neural tissue. Thus
the intravascular device may be adapted to stimulate an action
potential in a neuronal cell.
[0021] The electrode may be disposed on a mounting member. The
mounting member may comprise the electrode. The mounting member may
be adapted to conduct electrical signals. Thus, the mounting member
may comprise an electrically conductive member.
[0022] The intravascular device may comprise the mounting member.
The mounting member may comprise silicone.
[0023] Suitably, the mounting member may be encased in a stable
substance. The stable substance may encase the mounting member and
electrode. The stable substance may comprise silicone.
[0024] The mounting member may comprise a board. The board may be
encased in silicone. The board may comprise a printed circuit
board.
[0025] The mounting member may comprise a flexible flap. The
flexible flap may comprise silicone.
[0026] The mounting member may comprise a wire, or a wire may be
disposed on the mounting member. There may be a plurality of
wires.
[0027] The intravascular device may comprise a microchip. The
microchip may be electrically connected to the electrode. The wire
may extend between the electrode and the microchip.
[0028] The microchip may comprise a microprocessor.
[0029] The microchip may comprise a channel amplifier.
[0030] The microchip may comprise a digital signal converter.
[0031] The microchip may comprise an RF transmitter/receiver.
[0032] The wire may extend from the electrode to an external device
located outside of the body of the animal. There may be multiple
wires extending from multiple electrodes. The wires may congregate
to form a bundle which passes out of the body of the animal.
[0033] In another aspect, the invention may provide a retainer for
retaining the intravascular device at a position within the vessel.
The intravascular device may be disposed on the retainer
[0034] The retainer may be expandable. The retainer may comprise a
stent. The stent may comprise a mesh framework. The stent may be
expandable to take the shape of the surrounding vessel.
[0035] The stent may comprise a biodegradable or bioabsorbable
substance. The stent may be gradually broken down inside the
body.
[0036] Alternatively, the stent may comprise an inert substance
such as nitinol or platinum. Thus the stent may remain functional
in the body for several years, or even the lifetime of the
animal.
[0037] The retainer may comprise a probe. The probe may comprise an
elongate flexible micro-tube.
[0038] The stent may be adapted to expand when ejected out of an
end of the probe. The stent may be adapted to contract when
retracted into the probe. Thus the stent may be adapted to be
deployed, retrieved, and re-deployed. The redeployment may take
place at a different region within the vessel to that of the
earlier deployment.
[0039] In another form, the intravascular device may be mounted on
the probe. The stent may be absent in such an embodiment. The probe
may be adapted to conduct electrical signals to or from the
intravascular device. The probe may comprise a guide wire or cable.
The electrode wires may electrically connect with the guide wire or
cable.
[0040] The retainer may comprise an adhesive substance adapted to
cause adhesion of the intravascular device to the inside of the
vessel wall. The adhesive substance may be present on an outer
surface of the intravascular device.
[0041] In another aspect, the invention may provide a system for
sensing or stimulating activity of neural tissue comprising an
intravascular device for placement within an animal vessel, the
intravascular device being adapted to sense or stimulate activity
of neural tissue located outside the vessel proximate the
intravascular device.
[0042] The system may further comprise a guide member for guiding
the intravascular device to a region within the vessel proximate
the neural tissue to be sensed or stimulated.
[0043] The guide member may be adapted for passing into and through
the animal vessel. The guide member may be adapted for passage of
the intravascular device therethrough.
[0044] The guide member may comprise a catheter. Thus, the
intravascular device may be passed through the catheter to a region
within the vessel proximate the neural tissue to be sensed or
stimulated.
[0045] The catheter may be flexible. The external diameter of the
catheter may be less than 3 millimetres. The internal diameter of
the catheter may be greater than 0.5 mm.
[0046] The system may comprise a retainer or retaining member for
retaining the intravascular device at a region within the vessel
proximate the neural tissue to be sensed or stimulated. The
retaining member may be adapted for passage through the guide
member.
[0047] The system may comprise an electronic system.
[0048] The electronic system may comprise an electrode of the
intravascular device, and an electrically conductive member
connected with the electrode.
[0049] The electronic system may comprise a processor. The
processor may be located within or without the body of the animal.
For example, in one embodiment the processor is an internal
processor in the form of a microprocessor which is mounted on the
intravascular device, whereas in another form the electrodes are
electrically connected to an external processor such as a computer.
In yet another form, the processor may be an internal processor in
the form of a microprocessor which is mounted on a unit located in
the body separately to the intravascular device. The processor may
comprise a channel amplifier.
[0050] The processor may comprise a digital signal converter.
[0051] The processor may comprise an RF transmitter/receiver.
[0052] The processor may comprise at least one of an internal
processor disposed on the intravascular device, and an external
processor which is present outside the body.
[0053] A wireless form of the intravascular device may comprise the
internal processor. The internal processor may comprise a channel
amplifier, digital signal converter and RF
transmitter/receiver.
[0054] A non-wireless version of the intravascular device may
comprise the external processor. The external processor may
comprise the channel amplifier and the digital signal converter.
The RF transmitter/receiver may be absent in the non-wireless
version. This omission may be made due to power being directly
received from an external power source, or signals being directly
transmitted through a solid medium such as a wire. Thus, the system
may comprise a unit. The unit may be located separately to the
intravascular device. The unit may be located internally or in the
body. In a particular form, the unit may be located subcutaneously
in the pectoral region. There may be more than one internal unit.
Additionally or alternatively, the unit may be located externally.
For instance, the unit may be mounted on the patient's head. Thus,
the system may comprise at least one of an internal unit and an
external unit. Where there is an internal unit, an external unit
may be paired for wireless coupling therewith.
[0055] The external unit may be adapted to communicate wirelessly
with the internal unit. The external unit may be adapted for
placement about a region of the body adjacent the internal
unit.
[0056] The unit may be connected by an elongate electrically
conducting member, such as a wire, to the intravascular device. The
electrically conducting member may run substantially through the
vasculature between the unit and the intravascular device.
[0057] It may be that the internal unit, or one of the internal
units, is connected by wire to the intravascular device, whereas
the external unit, or one of the external units, is electrically
connected to an external device. The external device may comprise
at least one of a computer, stimulation box, and prosthetic
limb.
[0058] The unit may comprise a retaining mechanism for retaining
the unit in the desired position. The retaining mechanism may
comprise suture holes. The unit may comprise a power source. Power
may be transferred wirelessly from the external unit to the
internal unit. The wireless energy transfer may occur via
electromagnetic induction. The power source may comprise a pair of
conducting members adapted to be inductively coupled. The internal
unit may comprise one of the conducting members and the external
unit may comprise the other.
[0059] The internal unit may comprise a data transfer mechanism for
wireless transfer of data to the external unit. In a particular
form, the data may be transferred via the electromagnetic coupling.
In another form, an RF transmitter/receiver may be used for
wireless data transfer to the external unit.
[0060] The system may comprise alignment means for aligning the
external unit with the internal unit or intravascular device. The
alignment means may comprise a magnetic element. There may be a
pair of magnetic elements cooperatively disposed on the external
unit and the internal unit or intravascular device.
[0061] Additionally or alternatively, the power source may comprise
at least one of a battery or capacitor and RF
transmitter/receiver.
[0062] The unit may comprise a microchip. The microchip may
comprise a microprocessor with signal amplifier and
multiplexor.
[0063] The system may comprise a wireless transmission system for
wirelessly transmitting at least one of data and energy to or from
the intravascular device.
[0064] The wireless transmission system may comprise at least one
of a magnetic induction coil and an RF transmitter/receiver.
[0065] The system may comprise an alert system. The alert system
may be adapted for signaling an alert when the sensed activity of
neural tissue falls outside of a predetermined parameter.
[0066] The alert may comprise a warning signal which is activated
when sensed electrical activity indicates possible imminent onset
of seizure in the animal.
[0067] The system may comprise a device located separately to the
intravascular device, the device being adapted for at least one of
storage, processing, and transmission of data or energy to or from
the intravascular device. The device may be directly connected to
the intravascular device by a solid transmitting medium such as a
wire or fiber optic cable. Additionally or alternatively, the
intravascular device and the device may be wirelessly linked.
[0068] The device may comprise a wireless transmission mechanism
for transmitting at least one of data and energy between the
intravascular device and the device, or between two devices.
[0069] The device may comprise an internal device. The internal
device may comprise an internal unit. The internal unit may be
adapted for intravascular deposition. In another form, the internal
unit may be adapted for subcutaneous deposition.
[0070] The device may comprise an external device. The external
device may comprise an external unit adapted for placement on or
outside the body.
[0071] The external device may comprise a computer.
[0072] The device may comprise a prosthetic limb.
[0073] There may be multiple devices of same or different
forms.
[0074] The system may further comprise alignment means for aligning
the intravascular device, or internal device, with an external
device. The alignment means may comprise a pair of magnetic members
cooperatively disposed on the intravascular device, or internal
device, and the external device.
[0075] The system may comprise multiple intravascular devices
retained at various regions in one or more animal vessels. Thus,
electrical activity of various regions of neural tissue proximate
the intravascular devices may be sensed or stimulated.
[0076] In another aspect the invention may provide an apparatus for
sensing or stimulating activity of neural tissue comprising:
[0077] an intravascular device for placement within an animal
vessel, the intravascular device being adapted to sense or
stimulate activity of neural tissue located outside the vessel
proximate the intravascular device, and
[0078] a retaining member for retaining the intravascular device at
a region within the vessel.
[0079] The animal vessel may comprise an artery, vein, or lymph
vessel.
[0080] The animal vessel may comprise a mammalian vessel. In a
particular aspect, the mammalian vessel may comprise a human
vessel.
[0081] The human vessel may comprise a cerebral vessel. For
instance, the human vessel may comprise the anterior, middle, or
posterior cerebral artery.
[0082] In a particular form, the human vessel may comprise the
second or third branches of the middle cerebral artery which track
along the post central gyms of the brain.
[0083] In another aspect, the mammalian vessel may comprise a sheep
vessel. The sheep vessel may comprise the superior sagittal
sinus.
[0084] The vessel may be between 1 and 5 millimeters in diameter at
the region where the intravascular device is to be retained. In a
particular form, the vessel may be about 3 millimeters in diameter
at the region where the intravascular device is to be retained.
[0085] The neural tissue may comprise brain tissue.
[0086] The brain tissue may comprise the post central gyrus. The
brain tissue, or post central gyms, may comprise the motor
homunculus.
[0087] The brain tissue may comprise the pre central gyms. The
brain tissue, or pre central gyms, may comprise the sensory
homunculus.
[0088] Thus, depending on the position of the intravascular device
or devices, various regions of the brain may be sensed or
stimulated, including the pre central gyrus and the post central
gyms. This means that imagined movements of limbs or other parts of
the body may be sensed when sensing activity of the pre central
gyms, or movements of the limbs or other parts of the body may be
activated when stimulating the post central gyms.
[0089] Intravascular sensing of the electrical activity of various
regions of the brain may be used for monitoring epileptic patients
and detecting seizure focus points.
[0090] Intravascular stimulation of brain tissue may allow for
preoperative brain mapping.
[0091] Intravascular deep brain stimulation may be used in the
treatment of medical conditions. The medical conditions may include
Parkinson's Disease, Depression, Obsessive Compulsive Disorder or
Tourette's syndrome. Suitably, intravascular stimulation of deep
brain tissue may be used in the treatment of conditions including
Parkinson's disease, depression or Obsessive Compulsive
Disorder.
[0092] The system may comprise a brain computer interface
(BCI).
[0093] In another aspect the invention may provide a method for
sensing or stimulating electrical activity of neural tissue from
within an animal vessel.
[0094] The method may comprise using an intravascular device to
sense or stimulate the electrical activity of the neural tissue
from within an animal vessel proximate the neural tissue.
[0095] The electrical activity may comprise a local field
potential.
[0096] The electrical activity may comprise an action potential.
The electrical activity may comprise activity of a single
neuron.
[0097] The method may comprise guiding the intravascular device to
a region within the vessel proximate the neural tissue to be sensed
or stimulated. The intravascular device may be guided through a
catheter.
[0098] The method may comprise visualizing the vessel by a medical
imaging technique in order to facilitate guidance of the
intravascular device to the region of the vessel. The medical
imaging technique may comprise angiography.
[0099] The method may comprise retaining the intravascular device
at the region of the vessel. The intravascular device may be
retained against the inner wall of the vessel. The method may
comprise expanding a stent to retain the intravascular device
against the vessel wall. The method may comprise gradual biological
decomposition of the stent.
[0100] The method may comprise gradual biological incorporation of
the intravascular device into the vessel wall. The intravascular
device, or retaining member, is still considered to be `in` the
vessel when incorporated into the vessel wall or projecting into
the vessel wall from within the vessel.
[0101] The method may comprise endothelialisation of the
intravascular device into the vessel wall. The method may comprise
scarring of the intravascular device into the vessel wall.
[0102] The method may comprise amplifying a signal sensed by the
intravascular device.
[0103] The method may comprise converting the signal from analogue
to digital.
[0104] The method may comprise monitoring the signal. The signal
may be monitored external to the animal. The signal monitored may
comprise an intravascular electroencephalographic (EEG) signal.
[0105] The method may comprise powering the intravascular device
wirelessly. The intravascular device may be powered by passive
induction.
[0106] The intravascular device may be powered by radio waves. The
method may comprise using radiofrequency identification to transfer
data.
[0107] The method may comprise long term deposition of the
intravascular device in the animal vessel. The intravascular device
may be deposited in the animal vessel for multiple years. It may be
deposited in the animal vessel for the remainder of the animal's
lifetime.
[0108] The method may comprise sensing or stimulating electrical
activity of neural tissue from various regions in one or more
animal vessels. Thus, the electrical activity of various regions of
neural tissue may be sensed or stimulated.
[0109] The neural tissue may comprise a deep brain region. Thus,
the method may comprise sensing or stimulating electrical activity
of a deep brain region from within an animal vessel.
[0110] The method may comprise retaining or depositing the
intravascular device within an animal vessel proximate a deep brain
region.
[0111] The method may comprise detecting epileptic seizures, or the
focus thereof, by monitoring intravascular EEG activity.
[0112] The method may comprise mapping quantities or properties of
sensed or stimulated neural tissue. A property may comprise
function. Thus, the method may comprise mapping the function of
sensed or stimulated neural activity. The method may comprise brain
mapping. The method may comprise stimulating deep brain tissue in
order to map its function.
[0113] The method may comprise stimulating deep brain tissue for
treatment of a medical disorder. The disorder may comprise
Parkinson's disease, depression, or obsessive compulsive
disorder.
[0114] The method may comprise sending signals from the neural
tissue to a computer. The computer may receive signals relating to
the electrical activity of the neural tissue.
[0115] The method may comprise sending signals from a computer to
the neural tissue. These signals may be sent in response to the
signals received. The neural tissue may receive command signals
from the computer which excite the neural tissue.
[0116] The computer may be comprised of or by an external
device.
[0117] The method may comprise sending signals from the neural
tissue to an external device. These signals may be sent in response
to signals received by the neural tissue. The neural tissue may
receive command signals from the external device which excite the
neural tissue.
[0118] The external device may comprise an input device such as a
keyboard or mouse. Thus an input device may be controlled by the
animal.
[0119] The external device may comprise a prosthetic limb. Movement
of the prosthetic limb may occur in response to neural tissue
activity. Activation of neural tissue may occur in response to
stimulation, such as movement or touch, of the prosthetic limb.
[0120] The method may comprise wirelessly transmitting data or
energy between the intravascular device and a separate device
adapted for storing, processing, or transmitting signals to or from
the device.
[0121] The method may comprise retaining or depositing the
intravascular device within an animal vessel proximate a deep brain
region. Electrical activity of the deep brain region may be sensed
or stimulated.
[0122] The method may comprise retaining or depositing the
intravascular device in a vessel traversing the hippocampus. This
may allow detection of seizures or imminent seizure threat.
[0123] The method may comprise sensing changes in electrical
activity in the pre central gyms resulting from attempted movement
of natural, absent, or artificial body parts.
[0124] The method may comprise causing movement of a natural or
artificial body part by intravascularly stimulating the pre central
gyms.
[0125] The method may comprise placing an external unit over a
region of the body proximate the intravascular device, or over a
region of the body proximate an internal device linked to the
intravascular device, in order to facilitate wireless transmission
between the external device and the intravascular device, or
between the external device and the internal device.
[0126] In another aspect, the invention may provide use of an
intravascular device to sense or stimulate electrical activity of
neural tissue from within an animal vessel proximate the neural
tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
[0127] Illustrative but non-limiting embodiments of the invention
will now be described with reference to the drawings wherein:
[0128] FIG. 1 is a diagram showing a section of the second branch
of the middle cerebral artery of a human prior to deposition of a
wireless version of an intravascular device with stent.
[0129] FIG. 2 is a diagram of the section of the middle cerebral
artery shown in FIG. 1, with the stent expanded and the
intravascular device retained against the arterial wall.
[0130] FIG. 3 is a diagram showing the same region of the middle
cerebral artery as FIG. 1 with the stent and the intravascular
device deposited in the middle cerebral artery, and objects
required for insertion and deployment removed; the magnified
portion shows the intravascular device and expanded stent.
[0131] FIG. 4 is a diagram with a magnified portion showing the
intravascular device fused with the arterial wall, and the stent
absent due to biological decomposition.
[0132] FIG. 5 is a diagram showing how the intravascular device
acts as a brain computer interface with a prosthetic limb of a
human being.
[0133] FIG. 6 is a diagram showing a section of the second branch
of the middle cerebral artery of a human prior to deposition of a
wired version of an intravascular device with stent.
[0134] FIG. 7 is a diagram of the section of the middle cerebral
artery shown in FIG. 6, with the stent expanded and the
intravascular device retained against the arterial wall.
[0135] FIG. 8 is a diagram showing the same region of the middle
cerebral artery as FIG. 6 with the stent and the intravascular
device deposited in the middle cerebral artery and objects required
for insertion and deployment removed; the magnified portion shows
the intravascular device, expanded stent, and wire bundle which
connects externally.
[0136] FIG. 9 is a diagram showing the arterial pathway for
insertion of an intravascular device adjacent brain tissue; a wired
version of the device is shown.
[0137] FIG. 10 is a diagram showing a wireless version of the
intravascular device deposited in the brain, with the intravascular
device transmitting to and receiving signals from an external
computing and monitoring device.
[0138] FIG. 11 is a block diagram of the front end electronics of a
wireless version of the intravascular device which is to be located
within an animal vessel.
[0139] FIG. 12 is a block diagram of the back end electronics of a
wireless version of the intravascular device to be located external
to the body of the animal.
[0140] FIG. 13 is a diagram of a further wired version of an
intravascular device having an elongate probe with guide wire
passing therethrough.
[0141] FIG. 14 is a diagram showing a subcutaneous pectorally
located internal device which is wired back to the intravascular
device in a brain vessel and inductively coupled to an external
unit controlling a prosthetic limb.
[0142] FIG. 15 is a diagram of an internal unit.
[0143] FIG. 16 is a diagram of an external unit.
[0144] FIG. 17 is a block diagram illustrating possible electrical
and data flow within and between internal and external units.
[0145] FIG. 18 is a diagram illustrating various arrangements of
internal and external units.
[0146] FIG. 19 diagrammatically illustrates a wireless version of
the intravascular device which communicates directly with an
external unit overlying an adjacent region of the skull.
[0147] FIG. 20 is a diagram illustrating how the intravascular
device may be deposited in the hippocampal region of the brain for
pre-seizure detection or deep brain stimulation.
[0148] FIG. 21 is a diagram illustrating a testing procedure
utilizing stimulating electrodes for mapping and identifying
optimal regions for placement of the intravascular device within a
vessel.
[0149] FIG. 22 illustrates arterial vasculature traversing a human
brain and potential deposition sites for an intravascular
device.
[0150] FIG. 23 illustrates venous vasculature traversing a human
brain and potential deposition sites for an intravascular
device.
MODES FOR CARRYING OUT THE INVENTION
[0151] Referring to the drawings, there is shown a system,
generally designated 2, for sensing or stimulating activity of
neural tissue 54, such as brain tissue 192. The system 2 comprises
an intravascular device 4 for placement in an animal vessel 6, such
as the second branch 166 (see FIG. 22) of the middle cerebral
artery 160 of a human being 8. A wireless version of the
intravascular device 4 is shown in FIGS. 1-5 & 10, and a wired
version of the intravascular device 4 is shown in FIGS. 6 to 9.
[0152] The system 2 further comprises a retainer 12 for retaining
the intravascular device at a region within the artery 6, and a
flexible micro-catheter 10 which is to be passed up through the
subject's vascular system and allows passage of the intravascular
device 4 therethrough.
[0153] As shows more clearly in FIG. 3, the wireless version of the
intravascular device 4 comprises a 2 times 4 array of circular
electrodes 14.
[0154] The electrodes 14 are mounted on and project from the outer
surface of a rectangular semiconductor board 16 which in this
instance is in the form of a soft printed circuit board in a
silicone encasement.
[0155] Located centrally on an outer surface of the board 16,
between two 2 times 2 arrays of electrodes 14, is a rectangular
shaped microchip 18. The microchip 18 is electrically connected to
each of the electrodes 14 by electrode wires 56.
[0156] In the wired embodiment shown in FIGS. 6 to 9, the microchip
is omitted and the electrode wires 56 congregate to form a wire
bundle 58 which extends back through the vascular system and
connects with an external computing device 52 (see FIG. 9). Thus,
in the particular wired version of the intravascular device 4
shown, the external computing device 52 performs the processing
functions that the microchip 18 carries out in the wired
version.
[0157] The retainer 12 comprises a stent 20 and a flexible
micro-tube probe 22 which, in FIGS. 1 & 2, is attached to the
stent at one end, and in FIGS. 6 & 7, acts as a housing for the
stent when the stent is in a contracted and retracted state.
[0158] The stent 20 has a mesh configuration or lattice framework,
and is made of a bio absorbable substance which breaks down
gradually in the body, such as over a period of one to two years
when deposited into a human vessel. In an alternative embodiment
the mesh stent is made of an inert metallic substance which can
remain functional in the body for several years or the life of the
person.
[0159] The stent 20 as shown in FIGS. 6 to 8 is biased to expand.
Thus, when the stent 20 is retracted in the micro-tube 22 it
conforms to the inner wall of the micro-tube 22, and when it is
ejected from the proximal end of the micro-tube it expands,
conforming to the shape of the inner arterial wall (assuming the
diameter of the inner wall of the vessel is less than that of the
stent). The stent takes on a tubular shape when allowed to fully
expand.
[0160] The semi-conductor board 16 is mounted on the outer mesh
surface of the stent 20 so that when the stent is expanded to take
the shape of the vessel, the electrodes 14 of the intravascular
device 4 are brought into contact with the inner wall of the artery
6.
[0161] The guide catheter 10 has an internal diameter of about 0.15
mm which is enough to enable the passage of the micro-tube 22 with
retracted stent and intravascular device therethrough.
[0162] FIG. 13 shows a wired version of the system 2 wherein the
intravascular device 4 comprises a 2 times 4 array of electrodes 14
encased in a silicone flap 64.
[0163] The silicone flap 64 is mounted at the end of an elongate
tubular shaped silicone probe 22. Passing centrally through the
probe is a guide wire 62 and wire bundles 58. The wire bundles are
formed from individual wires 56 which extend from respective
electrodes which are attached to but insulated from the guide wire
62.
[0164] The guide wire passes out of the patient's body to external
processing equipment 34. As signal processing occurs externally,
there is no need for a microchip to be present in this version of
the intravascular device.
[0165] A wired system 2 such as that shown in FIG. 13 may be used
to sense or stimulate neural tissue in order to determine an
appropriate location for deposition of a wireless version of the
intravascular device.
[0166] The intravascular device 4 may be inserted and retained in
the desired region of a vein or artery 6 by performing the
following steps: [0167] A radio opaque contrast agent is injected
into the blood vessel 6 through which the catheter 10 is to be
inserted. In this instance, the contrast agent is injected into the
femoral artery or internal jugular vein in order to visualize blood
vessels and organs of the body using an imaging technique such as
radiography, CT and MR angiography. [0168] The catheter 10 is then
threaded into and through the femoral artery, and further up
through continuing branches of the femoral artery until it reaches
the desired position in the second branch of the middle cerebral
artery (see FIG. 9 for vascular pathway of catheter).
Alternatively, the catheter is threaded into branches of the venous
system, initially entering the internal jugular vein up through the
branches until entering the superior sagittal sinus and desired
position within the cortical veins. [0169] If not already present
within the catheter 10, the micro-tube 22 with intravascular device
4 and stent 20 is threaded up through the catheter 10 to proximate
the region where the intravascular device is to be retained (see
FIG. 6). [0170] The stent 20 is then protruded beyond the proximal
end of the micro-tube 22 which has housed it to this point. As the
stent 20 is protruded beyond the end of the micro-tube 22 it
expands to take on the shape of the blood vessel wall 6, thereby
retaining the intravascular device 4 against the inner wall of the
vessel 6. [0171] In another form of the invention, the catheter 10
is omitted from the system 2 and the micro-tube 22 acts as both the
guide for the stent through the vasculature, as well as the housing
for the stent before deposition. [0172] Where long term deposition
of the stent 20 is intended, the micro-tube 22 may be detached and
separated from the stent 20. A voltage may be delivered to a
discrete metallic area interconnecting the micro-tube and the
stent, thereby causing induced thermal fatigue of the discrete area
and detachment of the stent. [0173] If a new location of the
intravascular device is desired, the stent with intravascular
device may be withdrawn back into the micro-tube 22, and the system
2 moved to a desired region where redeployment of the stent with
intravascular device may then take place. [0174] For long term
deposition of the intravascular device, the catheter and detached
micro-tube are withdrawn back through and removed from the femoral
artery, leaving the stent and intravascular device retained at the
desired arterial region. [0175] In a wired version of the device, a
device wire 58 formed from a bundle of wires 56 extending from the
electrodes 14 may remain in the body during use of the
intravascular device 4 (see FIGS. 8 & 9). In one form, the
device wire 58 may extend from the intravascular device all the way
to and through the femoral artery where it exits the body and
attaches to external monitoring or stimulating equipment (see FIG.
9) for short term recording and monitoring during the angiography
procedure. Suitably, for longer term recording or monitoring, the
device wire may extend from the intravascular device, back through
the vasculature to a peripheral blood vessel such as the subclavian
artery when the intravascular device is retained in the arterial
system or the subclavian vein when the intravascular device is
retained in the venous system. At this point, the wire exits
through the vessel wall and into the subcutaneous tissue of the
pectoral region where it attaches to an internal unit 68 (see FIG.
14). [0176] In one form, the stent biologically decomposes
gradually over time, leaving only the intravascular device in
place, and the intravascular device is gradually endotheliolised
into the inner wall of the artery. [0177] In another form, the
stent is made of an inert material, such as platinum or nitinol
which is resistant to decomposition, thereby leaving the stent to
be incorporated along with the intravascular device into the
arterial wall by a process of endothelialisation and/or
scarring.
[0178] Depending on its location and function, neural tissue of the
brain adjacent the intravascular device may be stimulated, or
electrical activity in this tissue may be changed, in various
manners including: [0179] By the patient actively moving a part of
their body. For example, a patient's active movement of their right
arm may result from electrical activity in the area of the motor
homunculus representing the arm in the pre central gyrus 90 of the
brain. In such instances, one or more intravascular devices
retained or deposited in a portion of the middle cerebral artery or
cortical veins adjacent to the motor homunculus may sense
electrical activity such as electroencephalography, local field
potentials or action potentials in this area of the brain. [0180]
By the patient attempting active movement of a part of their body
which is no longer present or to which neural connection has been
lost. For example, where a patient has had their right arm
amputated, attempts to move their absent right arm may still
produce a change in electrical activity in the arm portion of the
motor homunculus despite the arm not being present. [0181] By part
of the patient's body being passively moved by an external force.
For example, a physical therapist may passively move a patient's
right arm without any active muscle contraction performed by the
patient. Such passive movement may cause increased activation of
part of the sensory homunculus in the post central gyms 190
relating to arm joint proprioception and skin sensation, as well as
sensory feedback resulting from the pressure and warmth of the
therapist's hands. [0182] By pricking the patient's forearm with a
pin 60, thereby causing a change or increase in electrical activity
in the sensory portion of the brain associated with touch and pain
in the hand (see FIG. 10). [0183] By the patient imagining,
remembering or performing a new mental activity, thereby causing
electrical activity to be produced in various regions of the brain.
[0184] By the patient developing an epileptic seizure. A foci of
electrical activity that sparks a seizure within brain tissue may
be detected with accurate spatial localisation by changes in
electroencephalography using one or more intravascular devices near
the area of seizure focus. [0185] By involuntary intrinsic
processes. For example, changes in electrical activity in regions
of the brain may result from conditions or disease processes such
as epilepsy, Parkinson's disease, depression and Obsessive
Compulsive Disorder. Deep brain activity may be particularly
affected by such conditions.
[0186] Once retained in the vessel, the intravascular device 4 may
be used to sense the electrical activity, or changes in the
electrical activity, of adjacent extra vascular neural tissue, and
the electrical activity may be processed, in the following manner:
[0187] The electric charge emitted from the stimulated or
pathological adjacent neural tissue is sensed and collected by the
electrodes 14, and conducted by wires 20 to the microchip 18 (see
FIG. 3). As shown in FIG. 11, the microchip houses a channel
amplifier 24, filter 26, analogue to digital converter 28, and an
RF transmitter/receiver 30. [0188] The signal from the electrodes
14 is passed to the channel amplifier 24 which amplifies the signal
from the electrodes. [0189] The amplified signal is converted from
analogue to digital by the converter 28. [0190] A microprocessor
controlled induction coil or RF transmitter 30 then transmits the
digital signal wirelessly to a corresponding induction coil or RF
receiver 32 which forms part of an external processing system 34,
such as a computer. The computer 34 also comprises a power source
36, a signal display 38, signal processor software 40 which is
adapted to perform feature extraction 42 and translation 44, and a
brain computer interface output 46 which in this instance is
adapted to cause mechanical limb movement 48 of a prosthetic limb
50. The signal display 38 is in the form of an intravascular EEG
signal which is displayed on a monitor 52. [0191] The intravascular
EEG signal may be processed by software which enables feature
extraction and translation for a brain computer interface. The
resultant BCI output 46 enables the patient to control operation of
devices in the external environment. This may include movement of
mechanical limbs 48 and control of computer inputting devices such
as mice or keyboards. [0192] Monitoring the display signal may
enable detection and diagnosis of conditions in the brain, such as
the detection of epileptic seizures or parameters which indicate
that a seizure is imminent. Further, detection and monitoring of
conditions such as Parkinsons disease, depression, and Obsessive
Compulsive Disorder may be achieved by monitoring intravascular EEG
signals from adjacent deep brain regions.
[0193] Once retained or deposited in the artery 6, the
intravascular device may be used to stimulate regions of adjacent
neural tissue in the following manner: [0194] In the wireless
version of the device 4, a signal is sent by the external RFID
receiver 32 and received by the RF transmitter/receiver 30 of the
intravascular device. The signal may be sent in response to a
signal transmitted by the intravascular device 4 to the external
computer 34, with the response to the transmitted signal being
determined by the signal processor software 40. [0195] The signal
is then transmitted from the RF transmitter/receiver 30 to the
electrodes in a form which may then be further transmitted to the
adjacent neural tissue, thereby causing excitation or activation of
a local field potential or action potential in the adjacent neural
tissue.
[0196] Intravascular neural stimulation may have various
applications such as in preoperative mapping whereby areas of a
patient's brain are stimulated to determine the nature of their
function. The purpose of preoperative mapping may be to locate
important or non-expendable areas of the brain that are not to be
sacrificed during operations such as brain tumour resections or
epilepsy focus resections.
[0197] There may be many therapeutic applications for intravascular
neural tissue stimulation including deep brain stimulation in the
treatment of Parkinson's disease, depression, Obsessive Compulsive
Disorder and Tourette's Syndrome. Advantageously such stimulation
may be achieved without the need for invasive brain surgery.
[0198] It should be noted that several intravascular devices can be
deployed in one or more vascular regions throughout the animal body
in order to sense or stimulate neural tissue focused in one area or
various areas throughout the body. Sensing neural activity in
various areas may be particularly applicable when diagnosing and
monitoring seizures in epilepsy.
[0199] Referring now to FIG. 14, there is shown a further system 2
comprising an internal unit 68 located subcutaneously in the left
pectoral region 118 and connected by wire 58 back through the
vasculature 6 to an intravascular device 4 deposited within a brain
vessel 6. The system further comprises an external unit 70 mounted
externally on the skin overlying the internal unit 68 and being
inductively coupled therewith, the external unit being connected by
wire 72 to a prosthetic limb 50.
[0200] As shown in FIG. 15, the internal unit 68 comprises an
internal mounting member 74 which defines suture holes 116 for
fixing the unit subcutaneously. Mounted on the internal mounting
member 74 is an internal microchip 76 comprising an application
specific integrated circuit. Also mounted on the internal mounting
member is an internal magnetic induction coil 78 connected to the
internal microchip 76, as well as an internal magnet 80.
[0201] The internal unit 68 in FIG. 15 is also shown having an
internal RF transmitter/receiver 82 and an internal battery or
capacitor 84, although it is envisaged that the battery and RF
transmitter/receiver may not be required in some versions of the
internal unit, particularly where electrical and data transfer is
already effectively achieved by wireless inductive coupling with
the external unit. However, inclusion of a battery adapted to be
charged by the inductive coupling may also be useful as a back-up
energy source when the external unit is moved to location remote
from the internal unit and ceases to effectively produce energy of
its own.
[0202] The internal unit 68 further comprises an alert system in
the form of a alert light 110 and a speaker 112, although it is
envisaged that other alert devices may be used, including vibrating
devices.
[0203] FIG. 16 shows the external unit 70 which comprises an
external magnet 114, external microchip 86 with application
specific integrated circuit, and an external magnetic induction
coil 88 wired to the microchip, all mounted on an external mounting
board. The external magnetic induction coil 88 and external magnet
80 are arranged to correspond with like components of the internal
unit 68.
[0204] The external unit 70 is located on the skin overlying the
internal unit 68. Attraction between the internal and external
magnets of the respective units facilitates achievement of optimal
alignment for transmission between the internal and external
magnetic induction coils.
[0205] The external unit 68 in FIG. 16 is also shown having an
external RF transmitter/receiver 122 and an external battery or
capacitor 120, although it is envisaged that the battery and RF
transmitter/receiver may not be required in some versions of the
external unit, particularly where electrical and data transfer is
already effectively achieved by wireless inductive coupling with
the external unit.
[0206] The external unit 70 further comprises a connection port 124
enabling connection of the external unit 70 with cable 126 which
may in turn be connected to an external device such as a computer
or power outlet thereby enabling wired transfer of data and energy
between the external unit 70 and another external device.
[0207] Also comprised by the internal unit 69 is an alert system in
the form of an alert light 110 and a speaker 112, although it is
envisaged that other alert devices may be used, including vibrating
devices. The alert system may be used for various alerts including
in cases of low power, device or system malfunction, completed
periods of monitoring or recording, or current or impending medical
pathology or irregularity.
[0208] The incorporation of a power source and information
processor in the internal unit version shown in FIG. 15 means that
these features may potentially be omitted from the intravascular
device of the system shown in FIG. 14. Thus, the deposited
intravascular device in this system may be similar to intravascular
device previously discussed with respect to FIG. 8, i.e. not having
its own power source or microchip, but comprising electrodes 14 and
a wire bundle 58 which extends down through the vasculature to
connect with the microchip 76 of the internal unit.
[0209] In the system of FIG. 14, the intravascular device 4 is
located in a portion of a vessel 6 adjacent the motor homunculus.
In this instance, the intravascular device 4 was passed into the
internal jugular vein 170 and guided up through the sigmoid sinus
172, transverse sinus 174 and into the superior sagittal sinus 178
where it is deposited. It is envisaged, however, that other routes
and places of deposition may also be suitable, including places for
deposition such as the cerebral veins 184 (see FIG. 23) branching
off the superior sagittal sinus, other veins lying adjacent the
motor cortex, the second branch of the middle cerebral artery 160
(see FIG. 22), and other arteries lying adjacent the motor
cortex.
[0210] Attempted active movement of the prosthetic limb 50 by the
human being 8 results in generation of action potentials in the
upper limb homuncular region of the precentral gyrus. The resultant
cortically originating changes in electrical potential are sensed
by the electrodes 14 of the intravascular device 4 and transmitted
along the wire bundle 58 to the microchip 76 of the internal unit
68.
[0211] FIG. 17 illustrates possible flow of data and/or energy
between the intravascular device 4, internal unit 68, external unit
70, and external device which comprises a prosthetic limb 50 in
this instance.
[0212] As previously mentioned, the electrical signal passes from
the electrodes 14 to the internal microchip. The internal microchip
76 comprises an application specific integrated circuit with
microprocessor 92 for processing the received signal. The microchip
further comprises an amplifier 94 for amplifying the signal, and a
multiplexer 96 for digitally converting the signal, before the
signal is passed to the internal inductive loop 78 and wirelessly
transmitted through the cutaneous pectoral tissue to the external
coil 88 of the external unit 70.
[0213] The external unit passes the signal through its own external
microchip 98 with microprocessor 100 which decodes the signal. The
external microchip further comprises a rectifier 102 for converting
the signal and an amplifier 104 for amplifying the signal. The
signal is decoded by the microprocessor and the decoded signal is
used to control microprocessors and motors on the prosthetic limb
50, thereby causing movement of the limb to occur in accordance
with the area and degree of precentral gyms activation.
[0214] The prosthetic limb comprises sensors 114 (see FIG. 14)
adapted to sense touch, temperature, pressure or vibration in the
area of the sensor 114. The sensors are smaller and more tightly
packed anteriorly in the robotic fingers than in the robotic
forearm, thereby providing more finely tuned sensation in the
fingers for grasping and handling objects.
[0215] When activated, the sensors 114 send electrical signal from
the prosthetic limb to the external unit where the signal is
processed and conducted across the skin to the internal unit where
further processing occurs, before the signal is passed up to the
intravascular device 4, or another intravascular device 4,
deposited adjacent the post-central gyrus. Here, the electrodes
stimulate the area of brain corresponding to the signal received
from the sensors 144, such that the patient is able to feel what is
sensed by the prosthetic limb.
[0216] Additionally or alternatively, the signal from the sensors
114 may be passed up to another intravascular device located in a
vessel adjacent the precentral gyrus. This signal causes the
intravascular electrodes 14 to stimulate the adjacent neural tissue
of the motor homunculus, thereby causing movement of the limb such
as may reflexively occur when the muscle spindles of a natural limb
are quickly stretched or the skin is burnt.
[0217] FIG. 18 illustrates various methods of connection from the
intravascular device 4 to the prosthetic limb 50 via internal and
external units, 68 and 70 respectively. As was evident in the
system of FIG. 14, method "C" shows a wire 58 running from an
intravascular device (not shown) through the vessel 6 before
piercing the vessel wall and connecting with an extravascular
subcutaneous internal unit 68. The internal unit communicates
wirelessly with an adjacent external unit 70 mounted on the skin
128, which external unit is wired to the prosthetic limb 50. It is
envisaged that regions other than the pectoral region may also be
suitable for placement of the internal and external units, such as
the neck region.
[0218] Method "A" shows an intravascularly placed internal unit
68c, which is wired to an intravascular device 4 (not shown)
communicating wirelessly with an external unit 70 disposed on the
skin 128 and wired to the prosthetic limb 50. Rather than having a
processor and wireless transmission system located on the
intravascular device, this arrangement allows the processor and/or
wireless transmission system to be located on the internal unit,
meaning that the intravascular device may be of smaller size, and
the wireless transmission system may be placed in a region which is
more suitable for wireless transmission to an external unit.
[0219] Method "B" shows a double induction coupling system whereby
an intravascular internal unit 68a, which is wired to an
intravascular device (not shown) communicates wirelessly across the
vessel wall with an adjacent proximal extravascular internal unit
68b. The internal unit 68b is in turn wired to a distal
subcutaneous internal unit 68c that communicates wirelessly across
the skin 128 with an external unit 70 which is mounted externally
on the skin and wired to the prosthetic limb. This arrangement
potentially allows for more closely coupled wireless transmissions
and avoids piercing of tissues such as vessels and skin.
[0220] Method "D" provides for an intravascular device 4 (not
shown) which is wired directly to an external unit 70 located on
the surface of the skin, which external unit is connected by wire
72 to the prosthetic limb. Thus, no internal unit is present in
this arrangement.
[0221] Referring now to FIG. 19 there is shown a system 2
comprising a wireless version of an intravascular device 4 which is
inductively coupled to an external unit placed over the skin
adjacent the region of deposition of the intravascular device. As
shown in the inset, intravascular device 4 comprises an array of
electrodes 14 connected by wires 56 to a microchip 18 which is in
turn connected to an internal magnetic induction coil 78. The
intravascular device further comprises an internal magnet 80 for
facilitating optimal placement of the external unit by magnetic
attraction. The external unit 70 shares the same features as that
shown in FIG. 16, and is connected by wire 72 to the prosthetic
limb 50.
[0222] The system 2 of FIG. 19 works in a similar fashion as that
shown in FIG. 14 except rather than the electrical signal received
by the electrodes being passed by wire 58 down through the
vasculature to an internal unit, the signal passes directly from
electrode wires 56 into the microchip 18 where similar processing
as occurred in the internal unit takes place. The processed signal
is then transmitted via magnetic induction to the external unit 70
mounted on the adjacent portion of skin overlying the skull.
[0223] FIG. 20 shows yet another system 2 wherein the intravascular
device is specifically lodged in a vessel 54 traversing the
hippocampus 54. For instance, intravascular device 4 may be entered
into the vascular system 6 via the cavernous sinus and passed up
therethrough before being deposited in the internal cerebral vein
or one of its branches 186 (see FIG. 23). Here, intravascular
device can be used as an early warning seizure detection system,
whereby abnormal excitation in hippocampal tissue adjacent the
intravascular device is sensed by the electrodes of the device, and
the electrical signal is in turn transmitted to an internal unit 68
which is located subcutaneously in the pectoral region in this
instance, although it is envisaged that the wire could run directly
to an external unit 70 mounted on to the outer surface of the skin.
Here, an alert system in the form of an alert light 110 or speaker
112 may be activated to cause the emission of light or sound,
thereby alerting the user that a seizure may be imminent, and
allowing them to take necessary prophylactic action such as the
ingestion of anti-epileptic drugs.
[0224] The internal unit may draw energy from an internal battery
or capacitor 84 which is adapted to be charged by magnetic
induction when the external units is located adjacent the internal
unit. Thus, this arrangement allows the external unit to be
situated remotely from the user, only being fastened to the skin
overlying the internal unit when transfer of data or charging of
the battery or capacitor is required. Alternatively, there may be
no external unit, and the internal unit may operate on a long life
battery, such as those used in cardiac pacemakers, activating alert
signals when the hippocampal signal threshold is passed.
[0225] The embodiment of FIG. 20 also shows an external unit
connected to a box 132 which is adapted to measure and compute
signals received. In another aspect, the box 132 may be adapted to
send electrical signals to the external unit, where the signals are
conducted to the internal unit and passed up by wire to the
intravascular device, thereby activating the electrodes to
stimulate adjacent deep cortical tissue. Thus, brain stimulation
may be achieved in such a fashion, with placement of the
intravascular device varying depending on the region of the brain
to be stimulated.
[0226] FIG. 21 illustrates how testing may be conducted to map or
identify optimal placement of the intravascular device 4. For
example, testing may occur preoperatively in humans prior to
long-term deposition of an intravascular device, or may be
performed in animals for mapping optimal locations in like
structures to humans.
[0227] In the testing procedure, the intravascular device 4 is
retained in a location within a vessel for testing. A hole is
drilled through the skin layer, skull and dura, and stimulating
electrodes 134 are inserted into the subarachnoid space 136 and
subdural space 138 beneath the skull 140, sub-dermally, and
externally on the skin, with each of the devices being connected by
wires 142 back to an external stimulating box 132. Under control of
the box 132, the electrodes 134 are used to stimulate areas of the
brain which are desired to be sensed, and the signal detected by
the intravascular device 4 is recorded. The procedure is then
repeated with the intravascular device retained in different
regions in the vessel to determine where optimal signal sensing
occurs. This location may be suitable for long term deposition of
an intravascular device for sensing and/or stimulating
purposes.
[0228] FIG. 22 illustrates arterial vasculature which leads to and
traverses a human brain, providing potential pathways for passage,
and sites for deposition, of one or more intravascular devices.
Specifically referenced is the common carotid artery 150, external
carotid artery 152, internal carotid artery 154, ophthalmic artery
156, anterior cerebral artery 158, middle cerebral artery 160,
anterior choroidal artery 162, posterior communicating artery 164
and the second branch of the middle cerebral artery 166 in which an
intravascular device 4 is deposited.
[0229] FIG. 23 illustrates venous vasculature which leads traverses
and passes from a human brain, providing potential pathways for
passage, and sites for deposition, of one or more intravascular
devices. Specifically referenced is the internal jugular vein 170,
sigmoid sinus 172, transverse sinus 174, straight sinus 176,
superior sagittal sinus 178, falx cerebri 180, inferior sagittal
sinus 182, cortical veins 184, in one of which an intravascular
device 4 is deposited, and internal cerebral vein 186 and its deep
branches, in one of which an intravascular device 4 is
deposited.
[0230] Where the terms "comprise", "comprises", "comprised" or
"comprising" are used in this specification, they are to be
interpreted as specifying the presence of the stated features,
integers, steps or components referred to, but not to preclude the
presence or addition of one or more other features, integers,
steps, components to be grouped therewith.
* * * * *