(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`(19) World Intellectual Property
`Organization
`International Bureau
`
`ONANAA
`
`(10) International Publication Number
`WO 2016/059556 A1
`(43) International Publication Date
`21 April 2016 (21.04.2016) WIPO:IPCT
`
`
`\=
`=
`
`(6)
`
`International Patent Classification:
`A61B 5/04 (2006.01)
`AGBIN 2/02 (2006.01)
`A61N 2/00 (2006.01)
`AGIN 1/36 (2006.01)
`
`(21)
`
`International Application Number:
`
`PCT/IB2015/057838
`
`(22)
`
`International Filing Date:
`
`14 October 2015 (14.10.2015)
`
`BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM,
`DO, DZ, EC, EE, EG, ES, FL, GB, GD, GE, GH, GM,GT,
`HIN, HR, HU,ID,IL,IN,IR, IS, JP, KE, KG, KN, KP, KR,
`KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG,
`MK, MN, MW, MX, MY, MZ, NA, NG, NL NO, NZ, OM,
`PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW,SA, SC,
`SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN,
`TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW.
`
`(25)
`
`(26)
`
`(30)
`
`(7)
`
`(72)
`
`(81)
`
`Filing Language:
`
`Publication Language:
`
`(84)
`
`English
`
`English
`
`Priority Data:
`62/064,924
`
`16 October 2014 (16.10.2014)
`
`US
`
`Applicant: MAINSTAY MEDICAL LIMITED [IE/IE];
`Clonmel House, Forster Way, Swords, County Dublin (IE).
`
`Designated States (unless otherwise indicated, for every
`kind of regional protection availabie): ARIPO (BW, GH,
`GM, KE, LR, LS, MW, MZ, NA, RW,SD, SL, ST, SZ,
`TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU,
`TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE,
`DK,EE, ES, FI, FR, GB, GR, HR, HU,IE, IS, IT, LT, LU,
`LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK,
`SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ,
`GW, KM, ML, MR,NE,SN, TD, TG).
`
`Inventors: CROSBY, Peter A.; 11706 3rd Strect, NE,
`Blaine, MN 55434 (US). JAAX, Kristen N.; 28854 Half Declarations under Rule 4.17:
`MoonPlace, Santa Clarita, CA 91390 (US). RAWAT,
`Prashant B.; 11706 3rd Street, NE, Blaine, MN 55434
`(US).
`
`Designated States (unless otherwise indicated, for every
`kind of national protection available): AE, AG, AL, AM,
`AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY,
`
`as to applicant's entitlement to apply for and be granted a
`patent (Rule 4.17(ii))
`Published:
`
`with international search report (Art. 21(3))
`
`(54) Title: SYSTEMS AND METHODS FOR MONITORING MUSCLE REHABILITATION
`
`(57) Abstract: System and method for rehabilitating a muscle and monitoring such rehabilitation are provided, the system including
`a user input receiver for receiving stimulation parameter inputs from a user, a stimulator for generating stimulations to be applied to
`a patient's body based on the stimulation parameter inputs, a signal receiver to receive, detect, and record a signal containing an
`evoked potential generated by the body in response to the stimulations, a signal processor tor processing the recorded signal, for ex -
`ample, by amplifying,filtering, digitizing and temporal averaging the recorded signal, a trigger detector to alert the signal processor
`module when stimulations are generated to enable synchronization ofthe response signal with the stimulus for accurate temporal av -
`eraging, and an output display for providing data representative of the evoked potential to the user.
`
`
`
`
`
`wo2016/059556A1|IIIIIINMIUMIIMTANMIATUYIATEIAAMTNAAT
`
`

`

`WO 2016/059556
`
`PCT/1B2015/057838
`
`SYSTEMS AND METHODS FOR MONITORING MUSCLE REHABILITATION
`
`re
`
`Cross-Reference to Related Applications
`
`[0001]
`
`This application claims the benefit of priority of U.S. Provisional Patent
`
`Application No. 62/064,924, filed October 16, 2014,
`
`the entire contents of which are
`
`incorporated herein by reference.
`
`II.
`
`Field Of The Invention
`
`[0002]
`
`This application generally relates to assessment of the physiological state of a
`
`muscle subject to therapeutic stimulation. In particular, this application is directed to a system
`
`and method for monitoring progress of muscular rehabilitation.
`
`III.
`
`Background Of The Invention
`
`[0003]
`
`Back pain in the lower, or lumbar, region of the back is common. In many cases,
`
`the cause of back pain is unknown. The human back is a complicated structure including
`
`bones, muscles, ligaments, tendons, nerves and other structures, which together form the
`
`spinal stabilization system. The spinal stabilization system may be conceptualized to include
`
`three subsystems: 1) the spinal column, which provides intrinsic mechanical stability; 2) the
`
`spinal muscles, which surround the spinal column and provide dynamic mechanical stability;
`
`and 3) the neuromotor control unit, which evaluates and determines requirementsfor stability
`
`via a coordinated muscle response. In a properly functioning system, neuromotor control unit
`
`sensors present in the connective tissue of the spinal column and the muscle spindles of the
`
`spinal muscles each transmit signals via nerves to the motor cortex of the brain to provide
`
`information such as the force a muscle is exerting or the position of a joint. The motor cortex
`
`uses signals from the body’s neuromotor control unit sensors to form a sense of the body’s
`
`position in space. This sense is referred to as proprioception. The motor cortex of the brain
`
`returns signals to the spinal muscles to control the spine’s position in space. Thus, in patients
`
`with a functional stabilization system, the three subsystems work together to form a feedback
`
`loop that provides mechanical stability to the spine. It is applicant’s realization that lower
`
`back pain often results from dysfunction of these subsystems and disruption of the fecdback
`
`loop.
`
`

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`WO 2016/059556
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`PCT/1IB2015/057838
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`[0004]
`
`Some cases of back pain are caused by abnormal mechanicsof the spinal column.
`
`The spinal column consists of vertebrae and ligaments, e.g. spinal ligaments, disc annulus,
`
`and facet capsules. Degenerative changes to these structures, injury of the ligaments, acute
`
`trauma, or repetitive microtrauma may lead to back pain via inflammation, biochemical and
`
`nutritional changes,
`
`immunological factors, changes in the structure or material of the
`
`endplates or discs, and pathology of neural structures.
`
`[0005]
`
`It is believed that in some patients with back pain, the spinal stabilization system
`
`is dysfunctional. Under normal circumstances, mechanoreceptors present in the ligaments,
`
`facet capsules, disc annulus, and other connective tissues generate signals describing spinal
`
`posture, motions, and loads. These signals provide information to the neuromuscular control
`
`unit, which generates muscle response patterns to activate and coordinate the spinal muscles
`
`to provide dynamic mechanical stability. The neuromuscular control unit produces a muscle
`
`response pattern based upon several factors, including the need for spinal stability, postural
`
`control, balance, and stress reduction on various spinal components. If the spinal column
`
`structure is compromised, for example, due to injury, degeneration, or viscoelastic creep, then
`
`muscular stability must be adjusted to compensate and maintain spinal stability. However,
`
`ligament injury, soft tissue fatigue, viscoelastic creep, and other connective tissue injuries
`
`may cause mechanoreceptors to produce corrupted signals about vertebral position, motion,
`
`or loads, leading to an inappropriate muscle response. In addition, muscles themselves may
`
`be injured, fatigued, atrophied, or lose their strength, thus aggravating dysfunction of the
`
`spinal stabilization system. Moreover, muscles may disrupt the spinal stabilization system by
`
`going into spasm, contracting when they should remain inactive, developing trigger points, or
`
`contracting out of sequence with other muscles. Such muscle dysfunction may cause muscle
`
`spindle mechanoreceptors to send abnormal signals to the motor cortex, which further may
`
`compromise normal muscle activation pattcrns via the feedback loops.
`
`[0006]
`
`Through such mechanisms,disruptions to the spinal stabilization system can result
`
`in spine instability, which can lead to low back pain. In particular, spine instability can result
`
`in the generation of high loads on spinal structures when the spine moves beyond its neutral
`
`zone. The neutral zone is a range of intervertebral motion, measured from a neutral position,
`
`within which spinal motion is produced with a minimal internal resistance. High loads can
`
`lead to inflammation, disc degcencration, facct jomt dcegcencration, and muscle fatiguc. Since
`
`the endplates and annulus have a rich nerve supply, it is believed that abnormally high loads
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`WO 2016/059556
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`PCT/1IB2015/057838
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`on such structures, resulting from spine instability, may be a common cause of pain. Load
`
`transmission to the facet joints also may increase with degenerative disc disease, leading to
`
`facet arthritis and facet joint pain.
`
`[0007]
`
`A need exists for improving spine stability in many patients suffering from lower
`
`back pain. It is applicant’s hypothesis that repetitive and episodic contraction of the local
`
`muscle system of the back may generate afferent signals to the brain capable of reactivating
`
`or awakening the spinal stabilization system, thereby stabilizing the spine and reducing pain.
`
`[0008]
`
`The local muscle system includes deep muscles, and portions of some muscles
`
`that have their origin or insertion on the vertebrae. These local muscles control the stiffness
`
`and intervertebral relationship of the spinal segments. They provide an efficient mechanism
`
`to fine-tune the control of intcrvertcbral motion. The lumbar multifidus, with its vertcbra-to-
`
`vertebra attachments, is an example of a muscle of the local muscle system.
`
`[0009]
`
`The multifidus is the largest and most medial of the lumbar back muscles. It has a
`
`complex structure with repeating series of fascicles stemming from the laminae and spinous
`
`processes of the vertebrae, which exhibit a consistent pattern of attachments caudally. These
`
`fascicles are arranged in five overlapping groups suchthat each of the five lumbar vertebrae
`
`gives rise to one of these groups. At each segmental level, a fascicle arises from the base and
`
`caudolateral edge of the spinous process, and several fascicles arise, by way of a common
`
`tendon, from the caudal tip of the spinous process. Although confluent with one another at
`
`their origin, the fascicles in each group diverge caudally to assume separate attachments to
`
`the mamillary processes, the iliac crest, and the sacrum. Some of the deep fibers of the
`
`fascicles that attach to the mamillary processes attach to the capsules of the facet joints next
`
`to the mamillary processes. The fascicles arriving from the spinous process of a given
`
`vertebra are innervated by the medial branch of the dorsal ramus nerve that issues from below
`
`that vertebra.
`
`[0010]
`
`The lumbar multifidus and other skeletal muscles consist of a number of
`
`specialized elongated cells mechanically coupled together. A nerve fiber connects to the
`
`muscle cells at a region called the end plate. The combination of the muscle cell or group of
`
`cells and the nerve fiber that innervates it is called a motor unit. Motor units come in different
`
`sizes, with larger motor units producing greater force than smaller motor units given equal
`
`stimulation. An electrical signal transmitted to a nerve will travel down the nerve fiber and
`
`tae
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`WO 2016/059556
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`cause depolarization of the cell wall of the muscle fiber, thereby triggering biochemical
`
`processes inside the muscle cell that generate a twitch of contraction and resultant force
`
`generation.
`
`[0011]
`
`Nerves to skeletal muscles generally include a mix of motor nerves and sensory
`
`nerves. Motor nerves are cfferent nerves, which carry electrical signals from the brain to
`
`cause an action in a muscle, and sensory nerves are afferent nerves, carrying signals from
`
`remote structures to the brain to provide informationto the brain.
`
`[0012]
`
`External electrical stimulation for causing muscle contraction has been known
`
`since Galvani observed such contraction in frogs in 1791. Over time, it became knownthat
`
`the most energy efficient way to apply electrical stimulation to cause a muscle contraction is
`
`to stimulate the nerve fibcr of the motor unit because the cncergy required to stimulate a nerve
`
`fiber to elicit contraction is about 1000 timesless than required to stimulate a muscle to elicit
`
`contraction.
`
`[0013]
`
`If an electrical stimulation electrode is placed on or adjacent to the nerve that
`
`supplies the muscle, then a single electrical pulse will cause a single contraction of the
`
`muscle referred to as a twitch. The force in the muscle rises rapidly and decays more slowly
`
`to zero. The amount of muscle that contracts, and hence, the force of contraction, in the
`
`twitch is determined primarily by the number of motor units stimulated.
`
`[0014]
`
`If additional stimulation pulscs are applicd, additional twitchcs arc produced. If
`
`the rate of stimulation is such that a new stimulation pulse is presented before the prior twitch
`
`has decayed, then the new twitch will be largely superimposed on the prior, producing a
`
`summation of force. As the stimulation rate is increased, this summation of force is such that
`
`the twitches blend together to generate a smooth contraction. The stimulation frequency at
`
`which the force production transitions from intermittent
`
`(rapid twitching)
`
`to smooth
`
`contraction is often referred to as the fusion frequency. Stimulation at a rate at or above the
`
`fusion frequency leads to smooth force generation. In general terms, stimulation at a rate
`
`significantly higher than the fusion frequency has minimal effect on the strength or nature of
`
`contraction and may, in fact, have an adverse impact on fatigue of the muscle. Stimulation at
`
`a frequency higher than necessary to achicve the desired (¢.g., maximum) force is energy
`
`inefficient, which is an important consideration for an implantable device.
`
`

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`WO 2016/059556
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`[0015]
`
`Functional electrical stimulation (FES) is the application of electrical stimulation
`
`to cause muscle contraction to re-animate limbs following damage to the nervous system
`
`such as with stroke or spinal cord injury. FES has been the subject of much prior art and
`
`scientific publications. In FES, the goal generally is to bypass the damaged nervous system
`
`and provide electrical stimulation to nerves or muscles directly, which simulates the action of
`
`the nervous system. Onc lofty goal of FES is to enable paralyzed people to walk again, and
`
`that requires the coordinated action of many muscles activating several joints. In patients with
`
`spinal cord injury, the sensory nervous system is usually damaged as well as the motor
`
`system, and thus the afflicted person loses proprioception of what the muscle and limbs are
`
`doing. FES systems often seek to reproduce or simulate the damaged proprioceptive system
`
`with other sensors attached to a joint or muscle.
`
`[0016]
`
`Neuromuscular Electrical Stimulation (NMES)is a subset of the general field of
`
`electrical stimulation for muscle contraction, as it is generally applied to nerves and muscles
`
`which are anatomically intact but malfunctioning in a different way. NMES maybe delivered
`
`via an external system or, in some applications, via an implanted system.
`
`[0017]
`
`NMES via externally applied skin electrodes has been used to rehabilitate skeletal
`
`muscles after injury or surgery to an associated joint. This approach is commonly used to aid
`
`in the rehabilitation of the quadriceps muscle of the leg after knee surgery. Electrical
`
`stimulation is known to not only improve the strength and endurance of the muscle, but also
`
`to restore malfunctioning motor control
`
`to a muscle. See,
`
`e.g, Gondin eft al,
`
`“Electromyostimulation Training Effects on Neural Drive and Muscle Architecture”,
`
`Medicine & Science in Sports & Exercise 37, No. 8, pp. 1291-99 (August 2005).
`
`[0018]
`
`An implanted NMESsystem has been used to treat incontinence by stimulating
`
`nerves that supply the urmary or anal sphincter muscles. For example, U.S. Patent No.
`
`5,199,430 to Fang describes an implantable electronic apparatus for assisting the urinary
`
`sphincterto relax.
`
`[0019]
`
`For
`
`rehabilitation of
`
`anatomically
`
`intact
`
`(/e.,
`
`functionally
`
`disordered)
`
`neuromuscular
`
`systems,
`
`the primary goal
`
`is
`
`to restore normal
`
`functioning of the
`
`neuromuscular system. One application for an implanted NMES system is to restore normal
`
`functioning of the spinal stabilization system in order to improve spine stability in patients
`
`suffering from lower back pain. Such an application is described in U.S. Patent Nos.
`
`

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`WO 2016/059556
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`8,428,728 and 8,606,358 to Sachs and U.S. Application Publication No. 201 1/0224665 to
`
`Crosby, cach of whichis incorporated herein by reference in its entirety. These references
`
`describe implanted electrical stimulation devices designed to restore neural drive and
`
`rehabilitate local muscles of the back, such as the multifidus muscle, to improve stability of
`
`the spine.
`
`It
`
`is theorized here that providing appropriate electrical stimulations to the
`
`multifidus muscle using an implanted NMES system to gencrate repetitive and episodic
`
`contractions of the multifidus muscle may reactivate the feedback loop and_spinal
`
`stabilization systemovertime.
`
`[0020]
`
`Another form of stimulation therapy is trans-cranial magnetic stimulation (TMS),
`
`which also may be used to activate skeletal muscles. In TMS, a time varying magneticfield is
`
`generated to induce an electrical current. Applying such a magnetic field with a coil
`
`positioned overa patient’s skull can induce an electrical current in the patient’s brain tissue.
`
`This technique has been used to stimulate portions of the motor cortex by applying and
`
`focusing a magnetic field over certain regions of the brain, primarily in the motor cortex. A
`
`patient’s response to TMSpulses can be observed as a muscle twitch or as an electrical signal
`
`such as an electromyogram (EMG). TMShas been used to reactivate the quadriceps muscle
`
`following loss of volitional quadriceps activation resulting from meniscectomy.
`
`[0021]
`
`One of the challenges of stimulation therapies such as NMES and TMSis
`
`monitoring to ensure the stimulation device is positioned properly, applying appropriate
`
`levels of stimulation, and resulting in a positive therapeutic effect. Monitoring can be
`
`especially challenging for deep muscles such as the deep fascicles of the lumbar multifidus,
`
`which are too deeply positioned for contractions to be reliably observed visually. A related
`
`challenge of NMES and TMSfor rehabilitation of skeletal muscles is to diagnose when the
`
`therapy has been successful and may be discontinued. This is particularly important with
`
`patients who cannot communicate, e.g., young children, or patients who do not want to
`
`communicate, e.g., malingerers who may be motivated for the therapy to not be successful as
`
`it would result in loss of worker’s compensation insurance.
`
`[0022]
`
`It would therefore be desirable to provide a system and method to objectively
`
`monitor progress and diagnose when stimulation therapy of a skeletal muscle has been
`
`successful. To further rescarch and the devclopment of future thcrapics, it would also be
`
`desirable to provide a system and method that enable mapping at the various areas of the
`
`motor cortex and enable generation and display of motor cortex representations of the
`
`6
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`WO 2016/059556
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`muscles. Accordingly, it would be advantageous to provide a system and method that enable
`
`controlled monitoring of muscle responses resulting from various motor cortex stimulations.
`
`Such muscle responses may result in recordable signals, such as evoked potentials.
`
`[0023]
`
`An evokedpotential is an electrical signal recorded from a part of the body, which
`
`results from the presentation of a stimulus to a portion of the body. Evoked potentials
`
`include, for example, somatosensory evoked potentials (SSEPs), visual evoked potentials
`
`(VEPs), motor evoked potentials (MEPs), and brain stem auditory evoked potentials
`
`(BAEPs). SSEPs consist of a series of electrical waves that reflect sequential activation of
`
`neural structures in the somatosensory pathways. SSEPs can be measured at the cortex of the
`
`brain or at various sites along the somatosensory pathway, including at peripheral nerves.
`
`SSEPs can be triggered with electrical stimulation along the somatosensory pathway, for
`
`example, at a peripheral nerve. SSEPs can also be triggered by mechanical stimulation near a
`
`peripheral nerve.
`
`[0024]
`
`Evoked potentials are currently used as a measure of nerve functionality in some
`
`clinical procedures. Current clinical uses of evoked potential testing include measuring nerve
`
`signal conduction velocity, which can be an important diagnostic tool for diseases of the
`
`nervous system, such as multiple sclerosis, and verifying spinal cord functioning during spine
`
`surgery, as described in U.S. Patent No. 8,016,846 to McFarlin et a/. and U.S. Patent No.
`
`7,981,144 to Geist ef al. Evoked potentials can also be used on a temporary basis as an aid to
`
`placing electrodes in or near the nervous system, for example, at the dorsal root ganglion, as
`
`described in U.S. Patent No. 7,337,006 to Kim ef a/. A variety of techniques have been
`
`developed for the analysis of evoked potentials, for example, the techniques described in U.S.
`
`Patent No. 8,391,966 to Luo e/ al, U.S. Patent No. 5,638,825 to Fukuzumi e/ a/., and U.S.
`
`Patent No. 8,498,697 to Yongefal.
`
`[0025]
`
`Compared to other biological signals, many types of evoked potentials are
`
`quite small. Often, in clinical situations, the small size of an evoked potential is not visible in
`
`the raw data when a single stimulus is applied. To extract the electrical signal of interest from
`
`the backgroundnoise, the technique of signal averaging is employed. Signal averaging can be
`
`spatial, temporal, or some combination (1.¢., spatio-temporal averaging). In spatial averaging,
`
`a mathcmatical combination of signals are collected over a region of spacc in rcsponsc to a
`
`stimulus. In temporal averaging, a mathematical combination of signals are synchronized in
`
`time in response to a stimulus. With temporal averaging, the electrical signals recorded
`
`wad
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`WO 2016/059556
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`PCT/1IB2015/057838
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`following the stimulus are sampled using an analog-to-digital converter, then the time series
`
`of the samples 1s added together and divided by the number of samples to preserve scaling.
`
`The time series is synchronized with the stimulus event. In this manner, the background
`
`signal, which is asynchronousto the stimulus, tends towards its mean of zero, and the evoked
`
`potential average tends to a useful value above the background noise. The signal-to-noise
`
`ratio improves with the square root of the number of responses that are averaged. As will be
`
`appreciated by one skilled in the art,
`
`the specific combination of filtering parameters,
`
`sampling frequency, and number of scans to be averaged is determined by the nature of the
`
`evoked potential to be measured.
`
`[0026]
`
`In the description provided herein, the term “evoked potentials” refers to electrical
`
`signals. There are other “evoked response” signals generated in response to a stimulus, such
`
`as force generation or movement of a muscle in responseto electrical sttmulation and motion
`
`of the eyes (saccade) in response to a visual stimulus.
`
`[0027]
`
`It would be desirable to provide a system or method to detect and measure evoked
`
`potentials and other evoked responses to objectively monitor progress, optimize treatment,
`
`and diagnose when rehabilitation of a skeletal muscle has been attained.
`
`[0028]
`
`It would be desirable to provide a system or method for monitoring and recording
`
`progress of NMESor TMSfor rehabilitation of the lumbar multifidus muscle.
`
`[0029]
`
`It furthcr would be desirable to provide a system or method that provides data
`
`needed to adjust
`
`the operating parameters of an NMES or TMS system based on
`
`measurements of muscle performance, thereby continually optimizing the stimulation system.
`
`[0030]
`
`It would also be desirable to monitor the effects of a stimulation system on a
`
`tissue’s electrical activity, for example, to confirm applicant’s hypothesis that repetitive and
`
`episodic contraction of the local muscle system of the back generates afferent signals to the
`
`brain capable of reactivating or awakening the spinal stabilization system. It would thus be
`
`desirable to provide a system and/or method capable of detecting and recording signals
`
`generated by a patient’s body in response to repetitive and episodic stimulations to, and
`
`contraction of, the local muscle system of the back.
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`WO 2016/059556
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`IV.
`
`Summary Of The Invention
`
`[0031]
`
`The present invention overcomes the drawbacks of previously-known systems by
`
`providing systems and methods for measuring a body’s response to stimulations to
`
`objectively monitor progress of, and make informed adjustments to, a stimulation
`
`rehabilitation protocol.
`
`[0032]
`
`The stimulation monitoring system includes: a user input receiver module
`
`configured to receive stimulation parameter inputs from a user; and an optional stimulation
`
`activator module configured to transmit the inputs received from the user to a stimulator
`
`module. The stimulator module may be configured to generate stimulations to be applied to a
`
`patient’s body based on the stimulation parameter inputs. The system further may include: a
`
`signal recciver modulc configured to reccive, detect. and record a rcsponsc signal gencrated
`
`by the body in response to the stimulations; a signal processor module configured to process
`
`the recorded response signal, for example, by amplifying, filtering, digitizing and temporal
`
`averaging the recorded signal; a trigger detector module configured to alert the signal
`
`processor module when stimulations are generated to enable synchronization of the response
`
`signal with the stimulus for accurate temporal averaging; and a graphical user interface
`
`configured to provide data representative of the response signal to the user.
`
`[0033]
`
`In accordance with one aspect of the present invention, a method for monitoring
`
`rehabilitation of a muscle is provided. The method may include:
`
`receiving from an
`
`extracorporeal source a first input defining a first stimulation protocol, wherein the first
`
`stimulation protocol includes a plurality of parameters for generation of an electric current or
`
`a voltage; automatically applying the first stimulation protocol to a portion of a patient’s body
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`to cause contraction of a skeletal target muscle associated with control of the lumbar spine;
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`automatically recording a response signal generated by the patient’s body in response to the
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`first stimulation protocol; automatically processing the recorded response signal to produce a
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`processed signal; automatically displaying information indicative of the processed signal;
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`receiving a second input from the extracorporeal source to adjust the first stimulation
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`protocol; and automatically applying an adjusted stimulation protocol to the body portion to
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`cause contraction of the skeletal target muscle.
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`[0034]
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`The first input may be entered by a clinician and may specify one or more
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`parameters of the first stimulation protocol. Such parameters may be selected from
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`parameters such as pulse amplitude, pulse width, stimulation rate, stimulation frequency,
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`ramp timing, cycle timing, session timing, duty cycle, contacts activated, percent of current
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`allocated to each contact, and location of stimulation.
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`[0035]
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`The target muscle may be weak, injured, or malfunctioning. In one embodiment,
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`the target muscle is the lumbar multifidus. In another embodiment, the target muscle is at
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`least one of the lumbar multifidus,
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`the transverse abdominus,
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`the erector spinae,
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`the
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`iliocostalis, or the longissimus.
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`The portion of the patient’s body to which the first
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`stimulation protocol is applied may be the medial branch of the dorsal ramus nerve, which
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`innervates the lumbar multifidus.
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`[0036]
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`The electric current or electric voltage of the first stimulation protocol may
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`include a plurality of clectrical pulscs generated by an implantcd ncuromuscular clectrical
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`stimulation device, and the electrical pulses may be applied to the patient’s body by a first
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`implanted stimulating electrode.
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`[0037]
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`The response signal may be at least one of an electrical signal, a force signal, or a
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`movement signal. In one embodiment,
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`the response signal
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`is an evoked potential. The
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`response signal may be recorded by a second implanted electrode (which may be a recording
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`electrode or a stimulating and recording electrode), and the recorded response signal or the
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`processed signal may be transmitted wirelessly to an external receiver. Alternatively, the
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`response signal may be recorded by a surface electrode attached to the patient at the head,
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`neck, spine or other part of the body, and the recorded response signal may be received by a
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`processor from the surface electrode via a wired or wireless connection. In another alternate
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`embodiment, the electric current may be generated by a trans-cranial magnetic stimulation
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`device and applied to the patient’s skull by an inductive coil, and the response signal may be
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`recorded by an implanted recording electrode implanted on, in, or near the deep skeletal
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`target tissue, and the recorded response signal or the processed signal may be transmitted
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`wirelessly to an external receiver.
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`[0038]
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`Processing the recorded response signal may include amplifying the recorded
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`response signal, filtermg the recorded response signal, digitizing the recorded response
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`signal, and/or taking a temporal average of the recorded response signal, if the recorded
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`response signal is an electrical signal. In an embodiment in which the recorded response
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`signal is temporally averaged, the method further may include generating a trigger signal
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`upon initiating application of the first stimulation protocol and synchronizing the recorded
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`response signal with the trigger signal.
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`[0039]
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`Information indicative of the processed signal may be displayed on a computer
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`monitor or other display screen. Such information may include a waveform of the processed
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`signal. Additionally or altcrnatively, the displayed mformation may include one or more
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`quantitative metrics of the processed signal, such as: amplitude, width, frequency, latency
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`relative to application ofthe first stimulation protocol, and/orslope.
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`[0040]
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`The method further may include recording a second response signal generated in
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`response to the adjusted stimulation protocol, processing the second response signal
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`to
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`produce a second processed signal, and displaying information indicative of the second
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`processedsignal.
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`[0041]
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`In accordance with another aspect of the present invention, a feedback loop
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`system for monitoring rehabilitation of a muscle is provided. The system may include: a user
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`interface configured to receive a first input from a user defining a stimulation protocol
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`comprising a plurality of parameters for generation of an electric current; a transcranial
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`magnetic stimulation device communicatively coupled to the user interface to receive the
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`stimulation protocol, the transcranial magnetic stimulation device comprising an inductive
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`coil positionable over a patient’s skull and configured to generate an electromagnetic field in
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`accordance with the stimulation protocol; an implantable device comprising a recording
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`electrode and a processor configured to receive, detect, and record a response signal
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`generated by the body in response to the stimulation protocol; a trigger detector
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`communicatively coupled to the transcranial magnetic stimulation device and configured to
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`transmit a wireless signal to the implantable device upon application of the stimulation
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`protocol; an external receiver comprising an electromagnetic or radiofrequency telemetry unit
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`wirelessly coupled to the implantable device and configured to receive the response signal
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`from the implantable device; and an output display having a screen configured to display data
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`representative of the response signal.
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`[0042]
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`The trigger detector may include an electromagnetic or radiofrequency telemetry
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`unit. The inductive loop of the transcranial magnetic stimulation device may be housed
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`within a helmet or other unit adjacent to or contacting the head. The user interface and the
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`output display may be integrated into a common device. Similarly, the trigger detector and
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`the external receiver may be integrated into a