U.S. patent application number 14/596118 was filed with the patent office on 2015-08-06 for neuromodulation systems and methods of using same.
The applicant listed for this patent is Mandheerej Nandra, Yu-Chong Tai. Invention is credited to Mandheerej Nandra, Yu-Chong Tai.
Application Number | 20150217120 14/596118 |
Document ID | / |
Family ID | 53524428 |
Filed Date | 2015-08-06 |
United States Patent
Application |
20150217120 |
Kind Code |
A1 |
Nandra; Mandheerej ; et
al. |
August 6, 2015 |
NEUROMODULATION SYSTEMS AND METHODS OF USING SAME
Abstract
Neuromodulation systems are described. An example
neuromodulation system includes a controller wirelessly
communicatively coupled to a host computer, a signal generator
communicatively coupled to the controller, and a plurality of
electrodes communicatively coupled to the signal generator. The
controller, in conjunction with the signal generator and the at
least one electrode are configured to deliver a stimulation to a
mammal based on an instruction received from the host computer. The
stimulation is configured to induce voluntary movement or restore
function in the mammal.
Inventors: |
Nandra; Mandheerej;
(Pasadena, CA) ; Tai; Yu-Chong; (Pasadena,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nandra; Mandheerej
Tai; Yu-Chong |
Pasadena
Pasadena |
CA
CA |
US
US |
|
|
Family ID: |
53524428 |
Appl. No.: |
14/596118 |
Filed: |
January 13, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61926457 |
Jan 13, 2014 |
|
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|
Current U.S.
Class: |
607/59 |
Current CPC
Class: |
A61B 2562/0271 20130101;
A61N 1/36185 20130101; A61N 1/0553 20130101; A61N 1/36003 20130101;
A61N 1/36139 20130101; A61B 2562/0219 20130101; A61N 1/36067
20130101; A61N 1/0558 20130101; A61B 2562/0247 20130101; A61B
5/4836 20130101; A61N 1/36103 20130101; A61N 1/3787 20130101; A61B
5/0031 20130101; A61B 5/0488 20130101 |
International
Class: |
A61N 1/372 20060101
A61N001/372; A61N 1/36 20060101 A61N001/36 |
Goverment Interests
GOVERNMENT LICENSE RIGHTS
[0002] This invention was made with government support under
EB0076151 awarded by the National Institutes of Health. The
government has certain rights in the invention.
Claims
1. A neuromodulation system comprising: a controller wirelessly
communicatively coupled to a host computer; a signal generator
communicatively coupled to the controller; and a plurality of
electrodes communicatively coupled to the signal generator; wherein
the controller, in conjunction with the signal generator and the at
least one electrode are configured to deliver a stimulation to a
mammal based on an instruction received from the host computer, the
stimulation being configured to induce voluntary movement or
restore function of the mammal.
2. The neuromodulation system of claim 1, further comprising a
multiplexer circuit configured to enable the processor to select a
first pair of the electrodes to deliver the stimulation.
3. The neuromodulation system of claim 2, wherein the multiplexer
circuit is configured to enable the processor to select a second
pair of electrodes to sense an electrical signal within the
mammal.
4. The neuromodulation system of claim 1, wherein the mammal is a
human.
5. The neuromodulation system of claim 1, further comprising a
wireless power receiver configured to: receive power wirelessly
from a wireless power supply; and rectify the received power into
at least one DC voltage for the controller and the signal
generator.
6. The neuromodulation system of claim 1, wherein the voluntary
movement is of a foot, a toe, an ankle, a knee, a leg, a hip, a
shoulder, an arm, a hand, a wrist, a finger, a waist, a trunk, a
neck, a head or a combination thereof and the voluntary movement
comprises at least one of standing, stepping, a walking motor
pattern, sitting down, sitting up, laying down, reaching, grasping,
pulling and pushing, swallowing and chewing, breathing, and
coughing.
7. The neuromodulation system of claim 1, wherein the stimulation
is applied over a cervical portion of the spinal cord or the
brainstem.
8. The neuromodulation system of claim 1, wherein the delivered
signal is applied epidurally over at least one of a lumbar portion,
a lumbosacral portion, and a sacral portion of the spinal cord.
9. The neuromodulation system of claim 1, wherein the delivered
signal is applied to a thoracic or thoracic-lumbar portion of the
spinal cord.
10. A method of inducing a voluntary movement in a mammal with a
spinal injury, the method comprising: receiving in a controller
from a wirelessly communicatively coupled host computer an
instruction to apply a stimulation to a mammal; instructing a
signal generator via the controller to apply the stimulation; and
applying via the signal generator to at least one electrode the
stimulation.
11. The method of claim 10, further comprising transmitting a
control instruction from the controller to a multiplexer circuit to
select the at least one electrode for applying the stimulation.
12. The method of claim 11, wherein selecting the electrode
includes selecting a pair of electrodes within a MEMS
microelectrode array and electromyography ("EMG") wires or
electrodes.
13. The method of claim 12, further comprising transmitting a
control instruction from the controller to a multiplexer circuit to
select the at least one electrode within the microelectrode array,
the EMG wires, or a sensor to sense an electrical signal within the
mammal.
14. The method of claim 13, wherein the sensor includes at least
one of a pressure sensor, a temperature sensor, a chemical sensor,
a light sensor, a photonic sensor, an acoustic sensor, a flow
sensor, a flex sensor, a gyroscope, and an accelerometer.
15. The method of claim 10, further comprising: receiving power
wirelessly in a wireless power receiver from a wireless power
supply; and rectifying the received power in a DC voltage for the
controller and the signal generator.
16. The method of claim 15, further comprising: determining in the
controller that received power is insufficient for the stimulation;
and transmitting a message to the wireless power receiver for
additional power.
17. A neuromodulation system comprising: a controller configured to
wirelessly receive operating instructions from a host computer; a
signal generator communicatively coupled to the controller; a
multiplexer circuit communicatively coupled to the controller and
the signal generator; a wireless power receiver electrically
coupled to a wireless power supply and configured to power the
controller, the signal generator, and the multiplexer circuit; a
plurality of EMG wires or electrodes electrically coupled to the
multiplexer circuit; and a microelectrode array including a
9.times.3 array of electrodes electrically coupled to the
multiplexer circuit, wherein the controller, in conjunction with
the signal generator, the multiplexer circuit, and at least one of
an EMG wire or electrode and an electrode within the microelectrode
array are configured to deliver a stimulation to a mammal, the
stimulation being configured to induce voluntary movement or enable
restoration of function in the mammal.
18. The neuromodulation system of claim 17, wherein the stimulation
includes an epidural stimulation.
19. The neuromodulation system of claim 17, wherein the multiplexer
circuit is configured to enable a pair of the EMG wires or a pair
of the electrodes within the microelectrode array to receive the
stimulation from the signal generator.
20. The neuromodulation system of claim 17, wherein the controller
is configured to transmit a control instruction to a multiplexer
circuit to select the at least one electrode within the
microelectrode array, the EMG wires or electrodes, or a sensor to
sense an electrical signal within the mammal.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
patent application No. 61/926,457, filed Jan. 13, 2014, the entire
disclosure of which is incorporated herein by reference.
SUMMARY
[0003] Described herein generally are neuromodulation systems. The
systems can include a programmable controller wirelessly
communicatively coupled to a host computer, a signal generator
communicatively coupled to the controller, and a plurality of
electrodes and/or sensors communicatively coupled to the signal
generator. In some embodiments, the controller, in cooperation with
the signal generator and the at least one electrode can be
configured to deliver a stimulation to a mammal based on an
instruction received from the host computer, the stimulation
thereby inducing voluntary movement and/or enabling restoration of
function.
[0004] In other embodiments, the neuromodulation systems can
include a multiplexer circuit configured to enable the processor to
select a first pair of the electrodes to deliver the stimulation.
The multiplexer circuit can be configured to enable the processor
to select a second pair of electrodes to sense an electrical signal
within the mammal.
[0005] In some embodiments, the stimulator system can receive a
signal or signals from one or more electrodes or pairs of
electrodes (or other communicatively coupled
sensors/devices/systems)
[0006] In some embodiments, the neuromodulation systems can further
comprise a wireless power receiver. The wireless power receiver can
be configured to: receive power wirelessly from a wireless power
supply; and rectify the received power into at least one DC voltage
for the controller and the signal generator.
[0007] The neurostimualtion systems can induce voluntary movements
of a foot, a toe, an ankle, a knee, a leg, a hip, a shoulder, an
arm, a wrist, a hand, a finger, a waist, a trunk, a neck, a head,
or a combination thereof. The voluntary movement can include at
least one of standing, stepping, a walking motor pattern, sitting
down, sitting up, laying down, reaching, grasping, pulling and
pushing, swallowing and chewing, breathing, and coughing. In some
embodiments the neurostimualtion system can induce or enable the
restoration of function of a targeted organ, organ system, or a
cell or cell body making up an organ or organ system.
[0008] The neurostimualtion systems can be used to apply
stimulation over a cervical portion of the spinal cord or the
brainstem. The delivered signal can be applied epidurally over at
least one of a thoracic, a thoraco-lumbar, a lumbar portion, a
lumbosacral portion, and a sacral portion of the spinal cord.
[0009] Methods of inducing movement, e.g., voluntary movement using
the herein described neurostimualtion systems are also described.
Methods of inducing a voluntary movement in a mammal with a spinal
injury can comprise: receiving in a programmable controller from a
wirelessly communicatively coupled host computer an instruction to
apply a stimulation to a mammal; instructing a signal generator via
the controller to apply the stimulation; and applying via the
signal generator to at least one electrode the stimulation
including a monophasic or biphasic signal and/or a mono-polar or
bi-polar stimulus.
[0010] The methods can further include transmitting a control
instruction from the programmable controller to a multiplexer
circuit to select the at least one electrode for applying the
stimulation.
[0011] In some embodiments, selecting the electrode can include
selecting a pair or pairs of electrodes within a MEMS
microelectrode array, electromyography ("EMG") wires, or EMG
electrodes.
[0012] The methods can further include transmitting a control
instruction from the controller to a multiplexer circuit to select
the at least one electrode to sense an electrical signal within the
mammal. The at least one electrode selected may be from within the
same microelectrode array, another microelectrode array and/or a
sensor. The sensor may include a pressure sensor, a temperature
sensor, a chemical sensor, a flow sensor, a flex sensor, a
gyroscope, or an accelerometer.
[0013] In some embodiments, the methods can further include
receiving power wirelessly in a wireless power receiver from a
wireless power supply; and rectifying the received power in a DC
voltage for the controller and the signal generator.
[0014] In still other embodiments, the methods can further include
determining in the controller that received power is insufficient
for the stimulation; and transmitting a message to the wireless
power receiver for additional power.
[0015] Neuromodulation systems are also described including: a
controller configured to wirelessly receive operating instructions
from a host computer; a signal generator communicatively coupled to
the controller; a multiplexer circuit communicatively coupled to
the controller and the signal generator; a wireless power receiver
electrically coupled to a wireless power supply and configured to
power the controller, the signal generator, the multiplexer
circuit; a plurality of EMG wires electrically coupled to the
multiplexer circuit; and a microelectrode array including (but not
limited to) a 9.times.3 array of electrodes electrically coupled to
the multiplexer circuit. In some embodiments, the controller, in
cooperation with the signal generator, the multiplexer circuit, and
at least one of an EMG wire and an electrode within the
microelectrode array are configured to deliver a stimulation (e.g.,
an epidural stimulation) to a mammal, the stimulation being
configured to induce voluntary movement or enable restoration of a
function in the mammal.
[0016] In some embodiments, the multiplexer circuit can be
configured to enable a pair of the EMG wires or a pair or pairs of
the electrodes within the microelectrode array to receive the
stimulation from the signal generator.
[0017] Additional features and advantages are described herein, and
will be apparent from the following Detailed Description and
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 shows a diagram of a view of an underside of an
implantable electrode array assembly, according to an example
embodiment of the present disclosure.
[0019] FIG. 2 shows a diagram of an enlarged view of a portion of
the assembly of FIG. 1, according to an example embodiment of the
present disclosure.
[0020] FIG. 3 shows a diagram of a cross-sectional view of a cable
system incorporating the assembly of FIG. 1, according to an
example embodiment of the present disclosure.
[0021] FIG. 4 shows a diagram of the cable system of FIG. 3 coated
with a coating, according to an example embodiment of the present
disclosure.
[0022] FIG. 5 shows a diagram of an example implant system
including the implantable electrode array assembly and cable system
of FIGS. 1 to 3, according to an example embodiment of the present
disclosure.
[0023] FIG. 6 shows a diagram of a multiplexer circuit, according
to an example embodiment of the present disclosure.
[0024] FIG. 7 shows a diagram of a wireless power supply and a
wireless power receiver, according to an example embodiment of the
present disclosure.
[0025] FIG. 8 shows a diagram of a controller, according to an
example embodiment of the present disclosure.
[0026] FIG. 9 shows a diagram of a stimulator, according to an
example embodiment of the present disclosure.
DETAILED DESCRIPTION
[0027] The present disclosure relates in general to the field of
neurological treatment and rehabilitation for injury and disease
including traumatic spinal cord injury, non-traumatic spinal cord
injury, stroke, movement disorders, brain injury, and other
diseases or injuries that result in paralysis and/or nervous system
disorder. Neuromodulation systems, devices, and methods are
provided to facilitate recovery of posture, locomotion, and
voluntary movements such as those of the fingers, hands, arms,
trunk, legs, and feet and recovery of autonomic, sexual, vasomotor,
speech, swallowing, chewing, respiratory and cognitive function, in
a human subject having spinal cord injury, brain injury, or any
other neurological disorder or impairment. In some embodiments, the
systems can include wireless communications.
[0028] The neuromodulation systems can include: a controller
wirelessly communicatively coupled to a host computer; a signal
generator communicatively coupled to the controller; and a
plurality of electrodes communicatively coupled to the signal
generator. In some embodiments, the controller, in cooperation with
the signal generator and the at least one electrode can be
configured to deliver a stimulation to a mammal based on an
instruction received from the host computer, the stimulation
including being configured to induce voluntary movement or enable
restoration of function.
[0029] The use of conventional wire electrodes for spinal cord
stimulation can be effective in facilitating locomotor recovery in
rats that have lower body paralysis. The use of a MEMS high-density
microelectrode array may offer greater selectivity and flexibility
in stimulation patterns, allowing for optimization of hindlimb
stepping motion and better study of electrophysiological changes
following the spinal cord injury. However, in some circumstances,
37 wires are needed for this passive implant and can often cause
health complications.
[0030] Although active electronics have been implemented to reduce
the number of wires, the present devices, e.g., implants, and
systems present a fully wireless spinal cord implant. In some
embodiments, this wireless implant can be for mammals. In other
embodiments, the implant can be for humans.
[0031] This wireless spinal cord implant can include an epidural
microelectrode array and optional electrodes for evoked potentials
and/or sensors.
[0032] The herein described implant is capable or can be configured
to both stimulate and record spinal cord, EMG responses, evoked
potentials, sensory evoked potentials, or a type of physiological
signal (i.e. electrical, chemical, photonic, mechanical, acoustic,
etc.) from a subjects body or body parts (i.e. organ or organ
system or the cells that make up the organ or organ system).
Additionally, the implant (by way of non-limiting example) may be
part of a closed loop system. In other embodiments the implant may
communicate with other systems and devices either implanted or
external to the body such as, for example, a pharmaceutical pump or
a robotic system.
[0033] In one example embodiment, the wireless implant can include
a 9.times.3 MEMS microelectrode array, a PCB with wireless
microprocessor/transceiver, EMG wires, a power coil configured to
receive power wirelessly, and sealing materials.
[0034] The microelectrode, by way of a non-limiting example, can be
fabricated with a parylene-metal-parylene sandwich structure. The
microelectrode can incorporate an improved microelectrode design
and other additions to improve mechanical reliability and minimize
delamination while retaining flexibility. The PCB can fit 22 IC
chips and about 100 passive components into a compact having a 10
mm.times.32 mm footprint.
[0035] In some embodiments, the microelectrode array can include a
plurality of electrodes. Each individual electrode within the
plurality of electrodes can be pulsed or stimulated individually.
In some embodiments, electrodes can be pulsed in pairs. A pair can
include two or more individual electrodes group together. In some
embodiments, an electrode or groups of electrodes can also be
configured to record electrical signals.
[0036] The stimulator associated with the wireless implant can be
configured to send a stimulating pulse to any pair of electrodes in
the electrode array. In some embodiments, the stimulator system can
receive a signal or signals from one or more electrodes or pairs of
electrodes (or other communicatively coupled
sensors/devices/systems). In other embodiments, the electrode array
can include more than 2 electrodes, more than 5 electrodes, more
than 10 electrodes, more than 5 electrodes, more than 20
electrodes, more than 25 electrodes, more than 30 electrodes, more
than 50 electrodes, more than 100 electrodes, more than 500
electrodes, more than 1,000 electrodes, more than 5,000 electrodes,
more than 10,000 electrodes, between about 2 electrodes and about
10,000 electrodes, between about 25 electrodes and about 35
electrodes, or between about 25 electrodes and about 100
electrodes. In some embodiments, the electrode array can include 27
electrodes, 54 electrodes, 108 electrodes, 216 electrodes, or
more.
[0037] In some embodiments, the circuitry encased in the wireless
electrode can switch between different electrode pairs very
rapidly, this circuitry can be configured to effectively send an
arbitrary pattern of pulses to a multi-electrode array or other
electrode array as described herein.
[0038] In one embodiment, the systems described can address 27
electrodes, two reference wires, and 16 EMG wires.
[0039] In some embodiments, the systems can include a maximum
stimulating voltage. This maximum stimulating voltage can be
achieved in a constant voltage mode. Example stimulating voltages
can be about .+-.5 V, about .+-.6 V, about .+-.7 V, about .+-.8 V,
about .+-.9 V, about .+-.10 V, about .+-.11 V, about .+-.12 V,
about .+-.13 V, about .+-.14 V, about .+-.15 V, about .+-.20 V, at
least about .+-.5 V, at least about .+-.10 V, at least about .+-.12
V, between about .+-.5 V and about .+-.20 V, or between about
.+-.10 V and about .+-.15 V. In one embodiment, the maximum
stimulating voltage can be .+-.12V.
[0040] In some embodiments, the systems can include a maximum
stimulating current. This maximum stimulating current can be
achieved in a constant current mode. Maximum stimulating currents
can be about .+-.1 mA, about .+-.2 mA, about .+-.3 mA, about .+-.4
mA, about .+-.5 mA, about .+-.6 mA, about .+-.7 mA, about .+-.8 mA,
about .+-.9 mA, about .+-.10 mA, at least about .+-.1 mA, at least
about .+-.2 mA, at least about .+-.4 mA, between about .+-.1 mA and
about .+-.10 mA, or between about .+-.4 mA and about .+-.6 mA. In
one embodiment, the maximum stimulating current can be .+-.5
mA.
[0041] In embodiments, the systems can provide an arbitrary
waveform stimulation. Arbitrary waveform stimulation can be about
10 kHz, about 20 kHz, about 30 kHz, about 40 kHz, about 50 kHz,
about 60 kHz, about 70 kHz, about 80 kHz, about 90 kHz, about 100
kHz, about 110 kHz, about 120 kHz, about 130 kHz, about 140 kHz,
about 150 kHz, about 160 kHz, about 170 kHz, about 180 kHz, about
190 kHz, about 200 kHz, at least about 50 kHz, at least about 80
kHz, at least about 90 kHz, between about 10 kHz and about 200 kHz,
or between about 90 kHz and about 110 kHz. In one embodiment, the
arbitrary waveform stimulation can be 100 kHz.
[0042] The systems can provide virtually any pulsed waveform. The
pulsed waveform can be as low as about 0.1 ms pulse width, as high
as 50 kHz frequency with a recording bandwidth up to about 60 kHz
(-3 dB).
[0043] The herein described systems can provide a digital-to-analog
(DAC) resolution between about 5 bits and about 15 bits, between
about 6 bits and about 13 bits, or between about 7 bits and about
12 bits.
[0044] The systems can have a characteristic configuration switch
time. Characteristic switch times can be about 1 .mu.s, about 2
.mu.s, about 3 .mu.s, about 4 .mu.s, about 5 .mu.s, about 6 .mu.s,
about 7 .mu.s, about 8 .mu.s, about 9 .mu.s, about 10 .mu.s, less
than about 10 .mu.s, less than about 8 .mu.s, less than about 4
.mu.s, between about 1 .mu.s and about 10 .mu.s, or between about 2
.mu.s and about 4 .mu.s. In one embodiment, the maximum stimulating
current can be 3 .mu.s.
[0045] The systems can configure and pulse a number of times per
given time period. In some embodiments, the systems can configure
and pulse about 10 times/millisecond (ms), about 20 times/ms, about
30 times/ms, about 40 times/ms, about 50 times/ms, about 60
times/ms, about 70 times/ms, about 80 times/ms, about 90 times/ms,
about 100 times/ms, about 110 times/ms, about 120 times/ms, about
130 times/ms, about 140 times/ms, about 150 times/ms, about 160
times/ms, about 170 times/ms, about 180 times/ms, about 190
times/ms, about 200 times/ms, at least about 10 times/ms, at least
about 20 times/ms, at least about 40 times/ms, at least about 60
times/ms, at least about 80 times/ms, at least about 100 times/ms,
between about 10 times/ms and about 200 times/ms, or between about
90 times/ms and about 110 times/ms. In one embodiment, the systems
can configure and pulse 100 times/ms.
[0046] The systems can be configured to simultaneously address a
given number of electrodes. In some embodiments, the electrodes can
be arbitrary. In one embodiment, the systems can simultaneously
address 2 electrodes, 4 electrodes, 6 electrodes, 8 electrodes, 10
electrodes, 12 electrodes, 14 electrodes, 16 electrodes, 18
electrodes, 20 electrodes, or any group of electrodes. Further, the
system can simultaneously address 2 arbitrary electrodes, 4
arbitrary electrodes, 6 arbitrary electrodes, 8 arbitrary
electrodes, 10 arbitrary electrodes, 12 arbitrary electrodes, 14
arbitrary electrodes, 16 arbitrary electrodes, 18 arbitrary
electrodes, 20 arbitrary electrodes, or more arbitrary electrodes.
In some embodiments, the systems can simultaneously address up to 8
arbitrary electrodes with limited configuration flexibility.
[0047] Further, the systems can be configured such that any two
electrodes, if not used for stimulating, can be chosen as the
differential pair for recording. Thus, any two electrodes not being
used for stimulation can be used for recording. However, the
recording electrodes are not limited to two at a time. The systems
can be configured to allow 4 electrodes, 6 electrodes, 8
electrodes, 10 electrodes, 12 electrodes, 14 electrodes, 16
electrodes, 18 electrodes, 20 electrodes, or more electrodes to be
used for recording.
[0048] The systems can communicate wirelessly and possess
characteristic data transfer rates. For example, the systems can
have wireless data transfer rates of about 250 kBps, 500 kBps, 750
kBps, 1,000 kBps, at least 250 kBps, at least 500 kBps, between
about 250 kBps and about 500 kBps, between about 250 kBps and about
1,000 kBps, or between about 250 kBps and about 750 kBps. These
data rates can be on ISM band 915 MHz. In one example embodiment,
the systems can have wireless data transfer rates of about 250
kBps.
[0049] The systems can also be configured as low power drawing
systems. The max power consumption of the systems can be less than
about 100 mW, less than about 90 mW, less than about 80 mW, less
than about 70 mW, less than about 60 mW, less than about 50 mW,
less than about 40 mW, less than about 30 mW, or less than about 20
mW. In one embodiment, the systems use less than about 100 mW of
power when active.
[0050] FIG. 1 illustrates an implantable electrode array assembly
100, according to an example embodiment of the present disclosure.
While the embodiment of the assembly 100 illustrated is configured
for implantation in a rat, embodiments may be constructed for use
in other subjects, such as other mammals, including humans, and
such embodiments are within the scope of the present teachings. The
assembly 100 is for use with a subject that has a spinal cord 330
(see FIG. 3) with at least one selected spinal circuit (not shown)
and a neurologically derived paralysis in a portion of the
subject's body. By way of a non-limiting example, the assembly 100
may be implanted epidurally along the spinal cord 330. The assembly
100 may be positioned at one or more of a sacral region,
lumbosacral region, a lumbar region, a thoraco-lumbar region, a
thoracic region, and/or a cervical region of the spinal cord 330 or
a brainstem.
[0051] By way of non-limiting examples, when activated, the
selected spinal circuit may (a) enable voluntary movement of
muscles involved in at least one of standing, stepping, reaching,
grasping, chewing, swallowing, breathing, voluntarily changing
positions of one or both legs, voiding the subject's bladder,
voiding the subject's bowel, postural activity, sitting, and
locomotor activity; (b) enable or improve autonomic control of at
least one of cardiovascular function, body temperature, and
metabolic processes; and/or (c) help facilitate recovery of at
least one of an autonomic function, sexual function, vasomotor
function, and cognitive function. Without being limited by theory,
it is believed that the selected spinal circuit has a first
stimulation threshold representing a minimum amount of stimulation
required to activate the selected spinal circuit, and a second
stimulation threshold representing an amount of stimulation above
which the selected spinal circuit is fully activated and adding the
induced neurological signals has no additional effect on the at
least one selected spinal circuit.
[0052] The paralysis may be a motor complete paralysis or a motor
incomplete paralysis. The paralysis may have been caused by a
spinal cord injury classified as motor complete or motor
incomplete. The paralysis may have been caused by an ischemic or
traumatic brain injury. The paralysis may have been caused by an
ischemic brain injury that resulted from a stroke or acute trauma.
By way of another example, the paralysis may have been caused by a
neurodegenerative brain injury. The neurodegenerative brain injury
may be associated with at least one of Parkinson's disease,
Huntington's disease, Alzheimer's, ischemia, stroke, amyotrophic
lateral sclerosis (ALS), primary lateral sclerosis (PLS), and
cerebral palsy.
[0053] If the paralysis was caused by a spinal cord injury at a
first location along the spinal cord 330, the assembly 100 may be
implanted (e.g., epidurally) at a second location below the first
location along the spinal cord relative to the subject's brain (not
shown).
[0054] The example assembly 100 is configured to apply electrical
stimulation to a portion of a spinal cord 330 of a subject. The
electrical stimulation may include at least one of tonic
stimulation and intermittent stimulation. The stimulation applied
may be pulsed. The electrical stimulation may include simultaneous
or sequential stimulation of different regions of the spinal cord.
The electrical stimulation applied by the assembly 100 may be below
the second stimulation threshold such that the at least one
selected spinal circuit is at least partially activatable by the
addition of signals generated by the subject. By way of a
non-limiting example, such subject generated signals may be induced
by subjecting the subject to physical activity or training (such as
stepping on a treadmill). These signals may be induced in a
paralyzed portion of the subject. By way of another non-limiting
example, the subject generated signals may include supraspinal
signals.
[0055] In one embodiment, the assembly 100 illustrated in FIGS. 1
to 3 can be configured for implantation in a rat. Thus, in some
embodiments of the assembly 100 illustrated, the implant can be
sized (e.g., about 59 mm by about 3 mm) and shaped for implantation
into the rat. However, embodiments may be constructed for use with
other subjects, such as other mammals, including humans.
[0056] FIG. 2 illustrates an enlarged portion 200 of the assembly
100 depicted in FIG. 1, according to an example embodiment of the
present disclosure. The assembly 100 may be characterized as being
a microelectromechanical systems ("MEMS") device. As mentioned
above, the assembly 100 is configured for implantation along the
spinal cord 330 (see FIG. 3) and to provide electrical stimulation
thereto. For example, the assembly 100 may provide epidural
stimulation to the spinal cord 330. The assembly 100 enables a high
degree of freedom and specificity in selecting the site of
stimulation compared to prior art wire-based implants, and triggers
varied biological responses that can lead to an increased
understanding of the spinal cord 330 and locomotive, movement,
autonomic and functional recovery for victims of spinal cord
injury.
[0057] Turning to FIG. 1, the assembly 100 includes a body portion
110, an electrode array 120, and a plurality of electrically
conductive traces 130. The body portion 110 includes a distal end
portion 112, a proximal end portion 114 (opposite the distal end
portion), a frame 140, and a grid structure 210 (see FIG. 2) for
each electrode E11-E19, E21-E29, and E31-E39 of the electrode array
120. Each of the grid structures 210 defines a plurality of cells
212. By way of a non-limiting example, the grid structures 210 may
each be constructed from parylene (e.g., parylene-C). In the
embodiment illustrated, the grid structure 210 includes 40
cells.
[0058] As mentioned above, the electrode array 120 includes the
plurality of electrodes E11-E19, E21-E29, and E31-E39 (e.g.,
9.times.3 electrodes). The electrodes E11-E19, E21-E29, and E31-E39
are arranged in a two-dimensional array. Each of the electrodes
E11-E19, E21-E29, and E31-E39 includes a plurality of electrically
conductive contacts 220. The contacts 220 are sites at which the
electrode (e.g., the electrode E37 illustrated in FIG. 2) will
contact the spinal cord (e.g., the dura). The contacts 220 are in
electrically communication with one another. The embodiment of the
electrode E37 illustrated includes 40 contacts 220. However, this
is not a requirement. As mentioned above, each of the electrodes
E11-E19, E21-E29, and E31-E39 corresponds to a unique one of the
grid structures 210. In the embodiment illustrated, for each of the
electrodes E11-E19, E21-E29, and E31-E39, each of the contacts 220
is positioned within a different one of the cells 212 of the
corresponding grid structure 210. The grid structure 210 may help
prevent delamination of the layers of the assembly 100 (see FIG.
1). The grid structure 210 and contacts 220 may be formed by
selectively etching a layer of substantially electrically
non-conductive material (e.g., parylene) adjacent a pad of
electrically conductive material (e.g., metal such as platinum or
gold) to define the grid structure 210 and expose portions of the
electrically conductive material within the cells 212 of the grid
structure to define the contacts 220.
[0059] While the electrode array 120 illustrated includes 27
electrodes, in other embodiments, the number of electrodes may
range from one electrode to about 1000 electrodes or more. As
discussed above, the electrode array 120 includes at least 10, at
least 15, at least 20, at least 25, at least 50, at least 100, at
least 250, at least 500, or at least 1000 electrodes. In various
embodiments, the inter-electrode spacing of adjacent electrodes in
the electrode array 120 varies from about 100 .mu.m or about 500
.mu.m, or about 1000 .mu.m or about 1500 .mu.m to about 2000 .mu.m,
or about 3000 .mu.m, or about 4000 .mu.m, or about 4500 .mu.m, or
about 5000 .mu.m. In various embodiments, inter-electrode spacing
ranges from about 100 .mu.m, about 150 .mu.m, about 200 .mu.m, or
about 250 .mu.m up to about 1,000 .mu.m, about 2000 .mu.m, about
3000 .mu.m, or about 4,000 .mu.m. In some embodiments, the diameter
(or width) of each of the electrodes E11-E19, E21-E29, and E31-E39
ranges from about 50 .mu.m, 100 .mu.m, 150 .mu.m, 200 .mu.m, or 250
.mu.m up to about 500 .mu.m, about 1000 .mu.m, about 1500 .mu.m, or
about 2000 .mu.m.
[0060] The electrode array 120 can be formed in any geometric shape
such as a square shape, rectangular shape, circular shape, tubular
shape, fan shape, or fusiform shape. Typically the size of the
electrode array 120 will be on the order of about 0.1 mm to about 2
cm, wide or in diameter, depending in part on the number of
electrodes in the electrode array 120. In various embodiments, the
length of the electrode array 120 ranges from about 0.01 mm, or 0.1
mm up to about 10 cm or greater.
[0061] One or more of the traces 130 is connected to each of the
electrodes E11-E19, E21-E29, and E31-E39. Referring to FIG. 2, in
the embodiment illustrated, two traces "T1" and "T2" are connected
to each of the electrodes E11-E19, E21-E29, and E31-E39. In
alternate embodiments, more than two traces 130 may be connected to
each of the electrodes E11-E19, E21-E29, and E31-E39. Connecting
more than one of the traces 130 to each of the electrodes E11-E19,
E21-E29, and E31-E39 helps ensure signals reach each of the
electrodes E11-E19, E21-E29, and E31-E39. In other words,
redundancy may be used to improve reliability. For each of the
electrodes E11-E19, E21-E29, and E31-E39, the traces 130 are
connected to each of the contacts 220 of the electrode and carry or
receive signals thereto. Openings 132 (see FIG. 3) formed (e.g.,
etched) in the body portion 110 expose portions of the traces
130.
[0062] The traces 130 may be used to selectively deliver electrical
signals (e.g., pulsed signals) to (or record signals from) the
electrodes E11-E19, E21-E29, and E31-E39. In this manner, only a
selected one or more of the electrodes (or pair of electrodes)
E11-E19, E21-E29, and E31-E39 may deliver stimulation to the spinal
cord 330 (see FIG. 3). The electrodes E11-E19, E21-E29, and E31-E39
are operably linked by the traces 130 to control circuitry, as
discussed in further detail below. The control circuitry is
configured to select one or more of the electrodes E11-E19,
E21-E29, and E31-E39 to activate/stimulate/record and/or to control
the parameters (e.g., frequency, pulse width, amplitude, etc.) of
the electrical stimulation. In various embodiments, the electrode
selection, frequency, amplitude, and pulse width are independently
selectable. For example, at different times, different electrodes
can be selected. At any time, different electrodes can provide
stimulation having different parameter values (e.g., frequencies,
amplitudes, and the like). In various embodiments, at least a
portion of the electrodes may be operated in a monopolar mode
and/or a bipolar mode. In such embodiments, constant current or
constant voltage may be used to deliver the stimulation.
[0063] In some embodiments, the traces 130 may receive signals from
implantable control circuitry and/or an implantable power source
(not shown). The implantable control circuitry may be programmed
and/or reprogrammed by an external device (e.g., using a handheld
device that communicates with the control circuitry through the
skin). The programming may be repeated as often as necessary.
[0064] FIG. 3 illustrates a cable system 300 incorporating the
assembly 100 of FIG. 1, according to an example embodiment of the
present disclosure. The example cable system 300 is illustrated
implanted along the spine 320 and spinal cord 330 of a rat. The
cable system 300 is composed of a spinal baseplate 340, EMG wires
350, and/or EMG electrodes 310. The baseplate 340 may be
constructed from a FR-4 PCB substrate. The baseplate 340 is
attached (e.g., by a suture 342) to a selected vertebrae (e.g.,
vertebrae "L2"). In the embodiment illustrated, the baseplate 340
is attached to the "L2" vertebrae. The assembly 100 is attached
(e.g., by a suture 344) to the spinal cord 300. In the embodiment
illustrated, the distal end portion 112 of the assembly 100 is
attached to the spinal cord 300 at a location adjacent vertebrae
"T13." The proximal end portion 114 of the assembly 100 is attached
to the baseplate 340 using a conductive material (e.g., conductive
epoxy) to bridge electrical connections. By way of a non-limiting
example, the proximal end portion 114 of the assembly 100 may be
secured to the baseplate 340 using Loctite M-121HP Medical device
epoxy.
[0065] The example EMG wires 350 may be connected to hind limbs or
other structure of a subject for inducing electrical stimulation or
recording one or more signals. The EMG wires 350 may be connected
to or include one or more EMG electrodes 310. In some embodiments,
the EMG wires 350 may be replaced with connections to other types
of electrodes, sensors, and/or systems/devices either wired or
wireless, or may also be omitted.
[0066] The EMG wires 350 include a plurality of wires 352. By way
of a non-limiting example, the wires 352 may each be connected to a
separate electrode 310. Each of the wires 352 may be constructed
from gold and include a Teflon coating. For example, 75 .mu.m gold
wires (e.g., Teflon coated gold wire manufactured by AM Systems)
may be used. The wires 352 may be soldered to the baseplate 340 and
connected by high density connectors 360 to the respective
electrodes 310. The traces 130 are connected to the baseplate 340
via the openings 132 formed in the body portion 110 of the assembly
100. By way of a non-limiting example, silver epoxy (not shown) may
be used to connect the traces 130 to the baseplate 340.
[0067] As shown in FIG. 4, the entire cable system 300 (except a
portion 368 of the assembly 100) may be coated with a coating 370
configured to insulate electrical connections and provide
mechanical strength while retaining the flexibility wherever
necessary. The implants described herein can be covered and/or
sealed to prevent exposure of the implant or portions of the
implant to tissues. In some embodiments, the entire implant can be
covered or sealed. In other embodiments, substantially all of the
implant is coated or sealed.
[0068] In one embodiment, the implant can be sealed using a
combination of parylene, an epoxy and a silicone. In some
embodiments, the implant can be sealed by coating it in silicone.
In other embodiments, an epoxy can be used to seal the implant, in
still other embodiments, parylene can be used to seal the implant.
Parylene is used to describe a variety of chemical vapor deposited
polyp-xylylene) polymers used as moisture and dielectric barriers.
In one example embodiment, parylene-C is used to seal the implant.
Combinations of epoxy, parylene and silicone can be used to seal
the implant.
[0069] By way of a non-limiting example, the coating 370 may
include a biomedical grade epoxy and a silicone elastomer (e.g.,
MDX 4-4210 Biomedical grade silicone).
[0070] Further, commercially available, hermetic metal packaging
cannot satisfy size and feed-through requirements for the presently
described wireless implants. New metal packaging and feed-through
assemblies can be mechanically designed, manufactured and
incorporated. However, in some embodiments, a new sealing technique
can be used to encase the wireless implants. The technique used to
seal the wireless implants can use parylene-C, epoxy, and/or
silicone.
[0071] In some embodiments, components of the implant can be
attached using an epoxy and then completely coated with silicone.
In other embodiments, components of the implant can be attached
using an epoxy and then completely coated with parylene. The
implant can be coated by methods such as dipping, brushing, spray
coating, rolling, vapor deposition, and the like. In one example
embodiment, the implant can be sealed by dipping the implant in a
coating solution. The coating solution can include epoxy, silicone,
and/or parylene. In some embodiments, the implant can be covered in
an epoxy, for example, by dipping and then coated with parylene,
silicone or a combination thereof.
[0072] The sealed wireless implant can remain sealed in vivo for a
useful lifetime of the implant. In some embodiments, the wireless
implant can remain sealed for at least one month, at least two
months, at least three months, at least four months, at least five
months, at least six months, at least one year, at least two years,
at least five years, between about two months and about 5 years,
between about 1 year and about 5 years, or between about 6 months
and about 5 years. In one embodiment, the technique of sealing the
wireless implant can provide sufficient sealing for at least two
months of in vivo functionality.
[0073] A silicone cap 380 (or overhanging portion) is formed on the
end of the baseplate 340 to protect the assembly 100 from external
moving tissue. The cap 380 may be formed from the same material as
the coating 370. Along portions of the assembly 100, the coating
370 may be implemented as a thin layer of silicone (e.g., about 100
.mu.m thick) to reduce stress concentration as the assembly 100
bends with the subject's spine 320 during movement. A thicker layer
of silicone applied to the assembly 100 may be detrimental to the
health of the spinal cord 330 because of increased pressure that is
applied by a more rigid assembly to the spinal cord. In other
words, flexibility may be an important feature of a successful
chronic implantable electrode array assembly.
[0074] FIG. 5 shows a diagram of an example implant system 500,
according to an example embodiment of the present disclosure. The
example implant system 500 includes the example implantable
electrode array assembly 100 discussed above in conjunction with
FIGS. 1 to 4. The system 500 also includes a host computer 502 that
is configured to be communicatively coupled to the implantable
electrode array assembly 100. The example host computer 502 may
include any computer, laptop computer, server, workstation,
processor, tablet computer, smartphone, smart-eyewear, smart-watch,
lab instrument, etc. The host computer 502 may be centralized or
distributed via a network or cloud computing environment. In some
embodiments, the host computer 502 may include an interface, which
enables remote devices (e.g., smartphones) to remotely specify data
(or instructions) to be transmitted to the implantable electrode
array assembly 100 and view data received from the implantable
electrode array assembly 100.
[0075] The example host computer 502 is configured to determine
and/or control data streams for transmission to the implantable
electrode array assembly 100. In some instances, a user may specify
the data streams (or instructions) to be transmitted. In other
instances, the host computer 502 may include machine-readable
instructions, which when executed, cause the host computer 502 to
operate one or more algorithms for determining data streams to be
transmitted to the implantable electrode array assembly 100. The
host computer 502 is also configured to receive, process, and/or
analyze data streams from the implantable electrode array assembly
100. In some instances, the host computer 502 may include
machine-readable instructions, which when executed, cause the host
computer 502 to operate one or more algorithms that analyze
received data streams from the implantable electrode array assembly
100. The host computer 502 may also be configured to provide a
graphical representation indicative of the data streams transmitted
to the implantable electrode array assembly 100 and/or a graphical
representation indicative of the data streams received from the
implantable electrode array assembly 100.
[0076] To facilitate communication between the host computer 502
and the assembly 100, the example implant system 500 includes a
controller 504. In other embodiments, to facilitate communication
between the host computer 502 and the assembly 100, the example
implant system 500 may includes a controller 504 The example
controller 504 includes a transceiver configured to convert
communications from the host computer 502 into a wireless format
(e.g., a low power RF format, Bluetooth.RTM., Zigbee.RTM., etc.)
for transmission to the assembly 100. The example controller 504 is
also configured to receive wireless signals (e.g., wireless streams
of data) from the assembly 100 and convert the wireless signals
into a format compatible for the host computer 502. In some
instances, the controller 504 is communicatively coupled to the
host computer 502 via a Universal Serial Bus ("USB"). In other
embodiments, the controller 504 is communicatively coupled
wirelessly to the host computer 502. The controller 504 may also
include memory to buffer or queue data streams for transmission. In
an embodiment, the controller 504 (by way of a non-limiting
example) may include the Texas Instruments.RTM. CC1111 Sub-1 GHz RF
System-on-Chip.
[0077] The example system 500 also includes a wireless power supply
506 configured to provide wireless power to the assembly 100. The
power supply 506 is communicatively coupled to at least one of the
host computer 502 and/or the controller 504 to receive power
control instructions. The example wireless power supply 506 may
include a Class E amplifier and inductive coupling components to
enable wireless transmission of power to the assembly 100 (as
discussed further in conjunction with FIG. 7). The example wireless
power supply 506 may also include a variable output to enable the
amount of power provided to the assembly 100 to be adjusted based
on, for example, application of the assembly 100, power
requirements of the assembly 100, and/or operations being performed
by the assembly 100. For example, the host computer 502 may
instruct the wireless power supply 506 to output relatively more
wireless power when relatively more stimulation signals are to be
provided by the assembly 100.
[0078] As discussed above, the example implantable electrode array
assembly 100 includes EMG wires 350, a MEMS microelectrode array
120, and implantable control circuitry. In the example embodiment
of FIG. 5, the implantable control circuitry includes a multiplexer
circuit 508, a wireless power receiver 510, a stimulator 512 (e.g.,
a signal generator/receiver), and a controller 514. It should be
appreciated that the implantable control circuitry of the assembly
100 may include additional or fewer components. For example, the
implantable control circuitry may also include a battery for long
term storage of power from the wireless power supply 506, a memory
to store instructions for operation of the implantable control
circuitry, a memory to store data streams transmitted from the host
computer 502 and/or detected by the assembly 100, etc. Further, the
implantable control circuitry of FIG. 5 may be combined and/or
partitioned differently based on hardware used, application,
etc.
[0079] The example wireless power receiver 510 (discussed further
in conjunction with FIG. 7) is configured to receive wireless power
from the wireless power supply 506 and convert the wireless power
into a DC voltage. In some embodiments, the wireless power receiver
510 is configured to output 3 V DC and 12 V DC. In other
embodiments, the wireless power receiver 510 may output 5 V DC. It
should be appreciated that the wireless power receiver 510 may be
configured to output one or more different DC voltages having any
magnitude based, for example, on power requirements of the other
implantable control circuitry, electromagnetic considerations of
the assembly, etc. The wireless power receiver 510 may also output
an AC signal and/or a power monitor signal (e.g., PWRMON) based on
requirements of the implantable control circuitry. For instance,
the wireless power receiver 510 is configured to output a power
monitor signal to the controller 514 to enable the controller 514
to monitor power received from the wireless power supply 506.
[0080] The example controller 514 (discussed further in conjunction
with FIG. 8) is configured to operate instructions that control the
multiplexer circuit 508 and/or the stimulator 512. The controller
514 includes a transceiver configured to receive a data stream
wirelessly from the controller 504 and convert the wireless data
stream for processing. The example controller 514 may also include
instructions that instruct the controller 514 how to control the
multiplexer circuit 508 and/or the stimulator 512 based on the data
stream generated by the host computer 502. For example, after
receiving a data stream that indicates that electrode pair E13 and
E33 are to be stimulated with a waveform having a specified
amplitude, shape, frequency, etc., the controller 514 transmits the
appropriate signal (e.g., appropriate digital word) via Clock,
Data, and EN (enable) lines to the multiplexer circuit 508 to cause
the specified waveform (e.g., stimulation signal) to be provided by
the E13 and E33 electrode pair of the MEMS microelectrode array
120.
[0081] In other instances, the example controller 514 is configured
to be programmed with operating instructions from the host computer
502 via the controller 504. The operating instructions may specify
the stimulation signal(s) and timing that is to be controlled
and/or managed by the controller 514. Such a configuration enables
the controller 514 to provide stimulation signals as specified
without having the controller 504 and/or host computer 502 in
constant contact or proximity of the subject.
[0082] The example controller 514 can also be configured to record
amplified signals (e.g., signals A1-A4) received from the EMG wires
350, EMG electrodes 310, the MEMS microelectrode array 120, or
other electrodes, sensors, or systems. In some embodiments, a senor
or system may wirelessly provide an indication of a recoded signal.
For instance, the host computer 502 may specify within a data
stream that electrodes E18 and E39 are to sense or otherwise detect
an electrical signal after stimulation by another electrode pair.
The controller 514 is configured to transmit the appropriate signal
(e.g., appropriate digital word) via Clock, Data, and EN (enable)
lines to the multiplexer circuit 508 to cause voltages detected by
the E18 and E39 electrodes of the MEMS microelectrode array 120 to
be amplified and recorded. In other embodiments, the host computer
502 may specify within a data stream that electrodes and/or sensors
350 are to record signal(s). The controller 514 is configured to
transmit the appropriate signal (e.g., appropriate digital word)
via Clock, Data, and EN (enable) lines to the multiplexer circuit
508 to cause voltages detected by the electrodes and/or sensors to
be amplified and recorded. The controller 514 may then transmit the
recorded data via a data stream to the transceiver 504.
[0083] The example controller 514 can also be configured to monitor
the wireless power received at the wireless power receiver 510. For
instance, the controller 514 is configured to enable that enough
power is provided to enable the multiplexer circuit 508 to output
the specified stimulating pulses to the subject. In one example,
the controller 514 may receive within a data stream a sequence of
pulses to be applied to the subject and determine that the power
being received at the wireless power receiver 510 is insufficient.
In response, the controller 514 may transmit a message to the
transceiver 504 for additional power (or an amount of additional
power needed), which causes the controller 504 to increase the
amount of power output by the wireless power supply 506. In an
embodiment, the controller 514 may include the Texas
Instruments.RTM. CC1111 Sub-1 GHz RF System-on-Chip.
[0084] The example stimulator 512 (discussed further in conjunction
with FIG. 9) is configured to provide a constant voltage and/or
current to the multiplexer circuit 508. The constant voltage and/or
current is provided via a Stim+ and a Stim- signal lines to the
multiplexer circuit 508. The amount of voltage and/or current
provided by the stimulator 512 may be set via a pulse width
modulation ("PWM") signal from the controller 514. The amount of
voltage provided may be based on a stimulation signal specified by
the host computer 502. A mode between voltage and current output
may be set via a mode signal from the controller 514.
[0085] The example multiplexer circuit 508 is configured to route
connections between the stimulator 512 and/or amplifiers and the
EMG wires 350, the EMG electrodes 310, the MEMS microelectrode
array 120, or other types of electrodes, sensors, systems, devices,
etc. FIG. 6 shows a diagram of the multiplexer circuit 508,
according to an example embodiment of the present disclosure. The
example multiplexer circuit 508 includes multiplexers M0, M1, M2,
M3, M4, M5, M6, M7, M8, and M9, which may include Analog
Devices.RTM. ADG1209 or ADG1208 multiplexers. The multiplexer
circuit 508 also includes shift registers SR1, SR2, SR3, and SR4,
which may include NXP Semiconductors.RTM. 74HC164 shift registers.
The multiplexer circuit 508 further includes amplifiers AMP1, AMP2,
AMP3, and AMP4, which may include Analog Devices AD8224 amplifiers.
The multiplexer circuit 508 receives as control inputs from the
controller 514 Clock, Data, and EN, which specify which of the EMG
wires 350, the EMG electrodes 310, the electrode pair within MEMS
microelectrode array 120, or other types of electrodes, sensors,
systems, devices, etc. are to be configured to output a stimulation
signal (e.g., Stim+ or Stim-) and/or configured to receive an
electrical signal. The multiplexer circuit 508 receives the
stimulation signals Stim+ and Stim- from the stimulator 512.
[0086] The desired configuration can be achieved by sending, for
example, a 30-bit serial data stream through the Clock and Data
inputs into the shift registers SR1 to SR4. The example shift
registers SR1 to SR4 in turn control or select which output of the
multiplexers M1 to M9 are to receive and output the Stim+ and Stim-
signals. The EN signal is used by the controller 514 to enable the
multiplexers M0 to M9. The example multiplexer M0 is configured to
disconnect the stimulation wires to the multiplexers M1 to M9 in
instances where the controller 514 instructs the multiplexer
circuit 508 to configure the EMG wires 350 and/or the MEMS
microelectrode array 120 to record. The multiplexer M0 is also
configured to select a polarity of the stimulation signal to be
provided to any one of the multiplexers M1 to M9 in instances where
the controller 514 instructs that a stimulation signal is to be
output to a subject.
[0087] The example multiplexers M1 to M9 are configured to receive
control signals from the shift registers SR1 to SR4 to determine
which output is to receive a stimulation signal. As shown in FIG.
6, the multiplexers M1 to M9 are interconnected to enable almost
any two of the electrodes within the MEMS microelectrode array 120,
the EMG wires 350, the EMG electrodes 310, or other types of
electrodes, sensors, systems, devices, etc. to be selected for
outputting a stimulation signal or detecting an electrical signal
within the subject. The illustrated embodiment shows the
multiplexers M1 to M9 connected to an electrodes designated by an
alpha-numeric identifier. The letter "E" refers to an EMG wire 350
where "E#+" and "E#" are EMG wire pairs. The letters "A", "B", and
"C" refer to spinal cord electrode columns shown in FIG. 1, where
the letter "A" corresponds to column 1, the letter "B" corresponds
to column 2, and the letter "C" corresponds to the column 3. Thus,
A3 refers to the electrode E13 of the MEMS microelectrode array 120
of FIG. 1. Outputs G1 and G2 refer to reference wires placed, for
example, near the shoulder and the lower back respectively on a
subject. The multiplexer M1 is configured to be selectively
connected to E1+, E5+, A5, B8, and C2. The multiplexer M2 is
configured to be selectively connected to E1-, E55, A4, B7, and C5.
The multiplexer M3 is configured to be selectively connected to
E2+, E6+, A3, B6, and C8. The multiplexer M4 is configured to be
selectively connected to E2-, E6-, A2, B5, and C7. The multiplexer
M5 is configured to be selectively connected to E3+, E7+, A1, B4,
C6, and A9. The multiplexer M6 is configured to be selectively
connected to E3-, E7-, A8, B3, C1, and C9. The multiplexer M7 is
configured to be selectively connected to E4+, E8+, A7, B2, and C4.
The multiplexer M8 is configured to be selectively connected to
E4-, E8-, A6, B1, C3, and B9. Finally, the multiplexer M9 is
configured to be selectively connected to G1, G2, A1, B1, C1, A9,
B9, and C9. It should be appreciated that some key electrodes
(e.g., the electrodes corresponding to A9, B9, and C9) have two
connections or outputs within the multiplexer circuit 508 to
further increase electrode pairing configurations. It should be
appreciated that the number of multiplexers and/or multiplexer
outputs may change based on the number of EMG wires 350 and/or
electrodes within the MEMS microelectrode array 120.
[0088] The example amplifiers AMP 1 to AMP 4 are configured to
amplify a differential signal received from selected ones of the
EMG wires 350, the EMG electrodes 310, electrodes within the MEMS
microelectrode array 120, and/or other types of electrodes,
sensors, systems, devices, etc. Each of the amplifiers AMP1 to AMP4
may be configured to have a gain of 200 and output respective
signals A1 to A4 representative of detected electrical pulses
within a subject. For example, the controller 514 may instruct the
multiplexer circuit 508 to enter a `listen mode` where the E1+ and
E1- EMG wires 350 and/or EMG electrodes 310 (or other types of
electrodes, sensors, systems, devices, etc.) are set to record or
otherwise sense an electrical signal and convey this signal via
multiplexers M1 and M2 to one or more of the amplifiers AMP1 to
AMP4, for transmission to the controller 514.
[0089] The example multiplexer circuit 508 of FIG. 6 may be
configured to operate in four different modes to meet experimental
requirements. A first mode enables a simulation signal to be
applied by any two electrodes within the MEMS microelectrode array
120, the EMG wires 350, and/or the EMG electrodes 310. A second
mode enables the multiplexer circuit 508 to record from any four
EMG wire pairs, EMG electrodes, or other types of electrodes,
sensors, systems, devices, etc. A third mode enables the
multiplexer circuit 508 to record from any two electrodes within
the array 120. A fourth mode enables the multiplexer circuit 508 to
record from four electrodes of the same column within the array 120
with respect to a fifth electrode. The example multiplexer circuit
508 is configured to switch between the different modes and
configurations of selected electrodes of the array 120 and/or EMG
wires 350 or EMG electrodes 310 within 1 microsecond, thereby
enabling the Stim+ and Stim- stimulation signals to delivery
relatively short pulses to many electrodes and/or EMG wires or EMG
electrodes in a one millisecond timeframe. Such a configuration
also enables the amplifiers AMP1 to AMP4 to rapidly switch input
signals to effectively record from eight or sixteen signals instead
of four within a specified timeframe.
[0090] FIG. 7 shows a diagram of the example wireless power supply
506 and the wireless power receiver 510 of FIG. 5, according to an
example embodiment of the present disclosure. As illustrated, the
example wireless power supply 506 uses inductor L1 to convert power
provided by supply V1 for transmission via a wireless medium. The
wireless power supply 506 also includes circuitry to convert the
voltage from supply V1 into an AC signal. The example wireless
power supply 510 uses indictor L2 to receive the power and convert
the power into an AC signal. The wireless power supply 510 also
includes a voltage regulator U2 and circuitry D1, D2, C9, and C10
configured to convert or rectify the AC signal into one or more DC
voltages (e.g., 3 V and 12 V).
[0091] FIG. 8 shows a diagram of the example controller 514 of FIG.
5, according to an example embodiment of the present disclosure.
The example controller 514 is wirelessly communicatively coupled to
the controller 504 via antenna E1 and corresponding circuitry. As
described above in conjunction with FIGS. 5 and 6, the example
controller 514 is configured to instruct the stimulator 512 to
operate in a voltage or current mode via the Mode1 and Mode2
outputs and instruct the multiplexer circuit 508 via the Clock,
Data, and EN outputs. The example controller 514 receives one or
more detected signals via inputs A1 to A4.
[0092] The example controller 514 may include memory to enable
instructions to be stored from the host computer 502 specifying how
and types of stimulation pulses are to be applied to a subject. The
example controller 514 may include memory to enable instructions to
be stored from the host computer 502 specifying which electrodes
and/or EMG wires/electrodes (or other types of electrodes, sensors,
systems, devices, etc.) are to be used for recording electrical
signals. The example controller 514 may include memory to store a
data structure of operations including when pulses were applied and
data representative of data received via inputs A1 to A4.
[0093] FIG. 9 shows a diagram of the example stimulator 512 of FIG.
5, according to an example embodiment of the present disclosure. As
discussed above, the example stimulator 512 is configured to
receive a Mode1 signal and a Mode2 signal from the controller 514
and accordingly output a constant voltage or constant current via
Stim+ and Stim- signal lines. For instance, if the Mode1 signal is
set to ground and Mode2 is set to a high impedance, then the
stimulator 512 is configured to operate in a constant voltage mode.
Alternatively, if the Mode1 signal is set to a high impedance and
Mode2 is set to ground, then the stimulator 512 is configured to
operate in a constant current mode. The magnitude of the voltage
and/or current may be set via a PWM signal from the controller
514.
[0094] Unless otherwise indicated, all numbers expressing
quantities of ingredients, properties such as molecular weight,
reaction conditions, and so forth used in the specification and
claims are to be understood as being modified in all instances by
the term "about." Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the following specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained by the present
invention. At the very least, and not as an attempt to limit the
application of the doctrine of equivalents to the scope of the
claims, each numerical parameter should at least be construed in
light of the number of reported significant digits and by applying
ordinary rounding techniques. Notwithstanding that the numerical
ranges and parameters setting forth the broad scope of the
invention are approximations, the numerical values set forth in the
specific examples are reported as precisely as possible. Any
numerical value, however, inherently contains certain errors
necessarily resulting from the standard deviation found in their
respective testing measurements.
[0095] The terms "a" and "an" and "the" and similar referents used
in the context of describing the invention (especially in the
context of the following claims) are to be construed to cover both
the singular and the plural, unless otherwise indicated herein or
clearly contradicted by context. Recitation of ranges of values
herein is merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range. Unless otherwise indicated herein, each individual value is
incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g. "such as") provided herein is intended
merely to better illuminate the invention and does not pose a
limitation on the scope of the invention otherwise claimed. No
language in the specification should be construed as indicating any
non-claimed element essential to the practice of the invention.
[0096] The use of the term "or" in the claims is used to mean
"and/or" unless explicitly indicated to refer to alternatives only
or the alternatives are mutually exclusive, although the disclosure
supports a definition that refers to only alternatives and
"and/or."
[0097] Groupings of alternative elements or embodiments of the
invention disclosed herein are not to be construed as limitations.
Each group member may be referred to and claimed individually or in
any combination with other members of the group or other elements
found herein. It is anticipated that one or more members of a group
may be included in, or deleted from, a group for reasons of
convenience and/or patentability. When any such inclusion or
deletion occurs, the specification is herein deemed to contain the
group as modified thus fulfilling the written description of all
Markush groups used in the appended claims.
[0098] Preferred embodiments of this invention are described
herein, including the best mode known to the inventors for carrying
out the invention. Of course, variations on those preferred
embodiments will become apparent to those of ordinary skill in the
art upon reading the foregoing description. The inventor expects
those of ordinary skill in the art to employ such variations as
appropriate, and the inventors intend for the invention to be
practiced otherwise than specifically described herein.
Accordingly, this invention includes all modifications and
equivalents of the subject matter recited in the claims appended
hereto as permitted by applicable law. Moreover, any combination of
the above-described elements in all possible variations thereof is
encompassed by the invention unless otherwise indicated herein or
otherwise clearly contradicted by context.
[0099] Specific embodiments disclosed herein may be further limited
in the claims using consisting of or consisting essentially of
language. When used in the claims, whether as filed or added per
amendment, the transition term "consisting of" excludes any
element, step, or ingredient not specified in the claims. The
transition term "consisting essentially of" limits the scope of a
claim to the specified materials or steps and those that do not
materially affect the basic and novel characteristic(s).
Embodiments of the invention so claimed are inherently or expressly
described and enabled herein.
[0100] Further, it is to be understood that the embodiments of the
invention disclosed herein are illustrative of the principles of
the present invention. Other modifications that may be employed are
within the scope of the invention. Thus, by way of example, but not
of limitation, alternative configurations of the present invention
may be utilized in accordance with the teachings herein.
Accordingly, the present invention is not limited to that precisely
as shown and described.
* * * * *