U.S. patent application number 12/428320 was filed with the patent office on 2009-08-13 for bipolar stimulation/recording device with widely spaced electrodes.
This patent application is currently assigned to Jus-Jas LLC. Invention is credited to Jennifer Chu.
Application Number | 20090204191 12/428320 |
Document ID | / |
Family ID | 38987346 |
Filed Date | 2009-08-13 |
United States Patent
Application |
20090204191 |
Kind Code |
A1 |
Chu; Jennifer |
August 13, 2009 |
Bipolar Stimulation/Recording Device With Widely Spaced
Electrodes
Abstract
A bipolar stimulator probe suitable for application of
intramuscular stimulation provides an active stimulator electrode
and a reference electrode as part of a single tool. The separation
between the electrodes is significantly greater than the electrode
separation of known bipolar stimulator probes and bipolar bar
electrode configurations. The probe tool may be configured to
permit adjustment of the fixed relative position of the electrodes
within a given range. By providing a relatively wide spacing
between the two electrodes, the tool can be used to approximate the
effect of monopolar stimulation with a separate reference
electrode, with the electrical stimulus producing less pain to the
patient compared to bipolar stimulation where the two electrodes
are spaced apart by only 2-4 cm or less.
Inventors: |
Chu; Jennifer; (Haverford,
PA) |
Correspondence
Address: |
BANNER & WITCOFF, LTD.
1100 13th STREET, N.W., SUITE 1200
WASHINGTON
DC
20005-4051
US
|
Assignee: |
Jus-Jas LLC
Haverford
PA
|
Family ID: |
38987346 |
Appl. No.: |
12/428320 |
Filed: |
April 22, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11830235 |
Jul 30, 2007 |
|
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|
12428320 |
|
|
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|
60834184 |
Jul 31, 2006 |
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Current U.S.
Class: |
607/115 |
Current CPC
Class: |
A61B 5/296 20210101;
A61B 2562/043 20130101; A61N 1/0551 20130101; A61N 1/3603
20170801 |
Class at
Publication: |
607/115 |
International
Class: |
A61N 1/04 20060101
A61N001/04 |
Claims
1. A bipolar stimulator probe comprising an active stimulator
electrode, a reference electrode and a user handle provided as part
of a single tool, wherein the positions of the electrodes are
substantially fixed with respect to each other such that the
inter-electrode spacing is at least 15 cm center to center.
2. The bipolar stimulator probe according to claim 1, wherein the
probe tool is configured to permit adjustment of the fixed relative
position of the electrodes within a given range.
3. The bipolar stimulator probe according to claim 1, wherein the
electrodes are mounted on the ends of spaced arms which are
attached to each other by a connection member extending cross-wise
between the arms.
4. The bipolar stimulator probe according to claim 3, wherein the
handle is placed at one end of the connection member.
5. The bipolar stimulator probe according to claim 4, wherein the
handle is tilted up at an obtuse angle relative to the connection
member.
6. The bipolar stimulator probe according to claim 1, further
comprising a trigger switch to permit a user to conveniently
activate the probe for stimulation applications.
7. The bipolar stimulator probe according to claim 6, wherein the
trigger switch is a touch-sensitive switch activated by pressure
exerted on a patient contact surface of the stimulating
electrode.
8. The bipolar stimulator probe according to claim 6, wherein the
trigger switch is activated by a push-button provided on the
handle.
9. The bipolar stimulator probe according to claim 1, wherein both
electrodes have surfaces for contact with the patient that are
circular in shape and have a diameter of 1-2 cm.
10. The bipolar stimulator probe according to claim 1, wherein both
electrodes comprise metallic patient contact surfaces.
11. The bipolar stimulator probe according to claim 1, wherein both
electrodes comprise felt pads providing patient contact
surfaces.
12. The bipolar stimulator probe according to claim 1, further
comprising a spaced electrode mounting structure provided in the
form of an arched arm with the active and reference electrodes
mounted on the ends thereof.
13. The bipolar stimulator probe according to claim 1, further
comprising a spaced electrode mounting structure in the form of a
generally flat bar to which the active and reference electrodes are
mounted.
14. The bipolar stimulator probe according to claim 1, further
comprising a spaced electrode mounting structure in the form of a
pair of arms which converge to form an obtuse angle.
Description
[0001] This application is a divisional application of Ser. No.
11/830,235, filed Jul. 30, 2007, which claims the benefit of prior
co-pending U.S. provisional application Ser. No. 60/834,184, filed
Jul. 31, 2006.
BACKGROUND OF THE INVENTION
[0002] Bipolar stimulator probes attachable to an electrical
stimulator device or an electromyographic (EMG) device are
commercially available for surface stimulation of peripheral
nerves. Such apparatus provide both a stimulation electrode and a
reference electrode on a single device. There are also bipolar bar
electrode configurations, and sets of separate (individual)
electrodes, for surface recording of nerve and muscle action
potentials, and that can also serve to provide electrical muscle
stimulation.
[0003] These types of devices can be used in surface stimulation
for eliciting muscle twitches of the type sought in a muscle pain
and discomfort relieving method developed by the present inventor,
referenced herein as Surface Applied Electrical Twitch Obtaining
Intramuscular Stimulation (SA-ETOIMS.TM.). This methodology is
described in U.S. provisional patent application Ser. No.
60/715,137, entitled "Intramuscular Stimulation Therapy Using
Surface-Applied Localized Electrical Stimulation," filed Sep. 9,
2005, and corresponding regular U.S. patent application Ser. No.
11/470,757, filed Sep. 7, 2006, which are hereby incorporated by
reference in their entireties. This technique involves the
provision of brief electrical stimulation at multiple motor
end-plate zones (twitch-points) in many muscles. It is important
that the stimulation method be "user friendly," to both patient and
treating clinician. That is, the stimulation should not cause
significant additional discomfort to the patient and the method
should be easy to apply for the clinician.
[0004] Commercially available standard bipolar stimulating probes
have an inter-probe distance of 2 cm or less between the active and
reference electrodes. This type of bipolar stimulation induces
significant stimulation pain making it undesirable for use in the
SA-ETOIMS.TM. procedure. In addition, due to the close proximity of
the active and reference electrodes, twitches that may be elicited
with such devices are small and have low forces, and therefore do
not provide significant pain relieving effects. Similarly, as
mentioned, surface electrodes that can be used for recording as
well as stimulation purposes are available in the form of a bar
electrode pair. Such devices have an inter-electrode distance of
about 3-4 cm, and thus the same problem of inducing stimulation
pain arises if these devices are used to perform SA-ETOIMS.TM..
Stimulation/recording electrodes are also available as separate
(individual) electrodes. However, separate individual electrodes
are less than ideal for use in the SA-ETOIMS.TM. procedure, since
both the active and reference electrodes have to be moved in
bi-manual fashion to multiple stimulus and reference sites, thus
slowing down and encumbering the SA-ETOIMS.TM. procedure and making
the procedure more difficult for the clinician. These difficulties
are alleviated to some extent by use of a monopolar stimulation
tool, as is explained below.
[0005] The present inventor has performed SA-ETOIMS.TM. using
monopolar stimulation, that is, with a generally pen-like tool
having a single electrode mounted on its tip, which is used in
conjunction with a separate reference electrode. Providing the
stimulation electrode in the form of a stiff, pen-like tool gives
the clinician a firm place to hold the tool in order to easily move
the electrode to different stimulation sites in a rapid and
efficient manner. The pain or discomfort relieving therapeutic
effects are substantially achieved only when such sites with large
force twitches are stimulated. SA-ETOIMS is performed in a
time-based fashion, i.e. in incremental treatment segments of 10-15
minutes sessions to one hour sessions. For therapeutic effects to
be substantial, it is essential that many large force twitch sites
be sought, located and treated within the limits of timed sessions
which are affordable and paid for by the patient as fee-for-service
performed. To be able to search for as many large force twitch
sites as possible within a given time-frame, the electrode needs to
be moved to another site as soon as the twitch is elicited, i.e.,
within a fraction of a second. Therefore, it is crucial that the
stimulation probes and reference electrodes allow expedient
performance of the SA-ETOIMS procedure. However, a stimulation
electrode provided in the form of a known-type adhesively applied
disposable electrode has no firm place for the clinician to hold
onto effectively, and is also impractical for efficient use in a
treatment method involving electrode relocation every fraction of a
second. The monopolar stimulation probe, similar in size and length
to that of a pen, is very useful in SA-ETOIMS procedure and can be
easily applied onto the skin surface for stimulation to evoke
muscle twitches and to facilitate the search for large force twitch
sites. However, the monopolar stimulation method requires use of a
separate remote surface reference electrode, which is typically a
known-type adhesively applied disposable electrode. The treatment
is less painful than with bipolar stimulation with electrodes that
are spaced 2-4 cm or less apart. However, monopolar stimulation has
disadvantages.
[0006] With monopolar stimulation, moving the stimulating probe to
different stimulus points has to be accompanied by relocating the
disposable separate reference electrode to different body sites,
multiple times, to avoid repetitive unnecessary stimulation and
induced pain at the reference site. This type of surface reference
electrode is not conducive to rapid movements, e.g., every second.
Therefore, in practice, the electrode is moved after every minute
or so. This bimanual work wastes time for the treating clinician
since the disposable reference electrode will lose its
adhesiveness, dislodge and/or fall off when subjected to multiple
re-positioning and re-application onto the skin surface.
[0007] To avoid skin irritation from repetitive stimulation at one
reference site only, and to avoid having to often move the single,
separate reference electrode from place to place, several reference
electrodes can be placed at different sites on the skin. By
rotating the activation of different reference electrodes, there is
better and more even distribution of the stimulus to different
reference sites. This reduces the number of times any single
reference electrode is subjected to removal and relocation.
However, to activate a reference electrode placed at a different
site, the clinician has to detach an alligator clip from the first
reference electrode and re-attach it onto the next reference
electrode with one hand, since the other hand holds onto the
monopolar probe used for treatment. This creates inconvenience for
the clinician since the alligator clip might not attach well when
performed single-handedly. If bimanual attachment is required, it
is disruptive to the treatment. It is also cumbersome since the
multiple electrodes still need to be physically removed and rotated
for placement at other skin sites to avoid discomfort at sites that
have undergone previous repetitive stimulation. In prolonged
treatments necessitating multiple different site placements of the
reference electrodes, the electrodes can eventually lose their
adhesiveness also causing them to fall off the skin surface.
Additionally, when the reference electrode does not stick properly
to the skin, the reduction in contact area of the reference
electrode to the skin induces more treatment pain.
[0008] For optimal pain relieving results with SA-ETOIMS.TM., it is
desirable to search for as many muscle motor points that can
produce large force twitches as quickly as possible in a time-based
treatment. Stimulation can be enhanced, and the yield of large
force twitches made easier, when the surface reference electrode is
placed at a distance from the stimulating probe. If the reference
electrode is placed close to the stimulating probe, the treatment
is painful and the twitches are small. The further the reference
electrode is placed away from the stimulating probe, e.g., by as
much 2-3 feet, the easier it is to elicit the sought-after large
force twitches from deeply situated motor end plate zones
(twitch-points). As one example, the reference electrode can be on
the mid or low back region while stimulating calf muscles or arm
muscles, but this creates a problem for the clinician if the
reference electrode is at a site not within easy reach. The
clinician then has to temporarily stop the treatment every time
he/she has to reach over to the reference electrode or has to move
closer to re-position the remote reference electrode to another
location within reach.
[0009] Additional disadvantages of the monopolar stimulation
approach (with separate reference electrode) include the fact that
the lengthy separated wires of the stimulating and reference
electrodes tend to get tangled, requiring that the clinician stop
the treatment to untangle the wires. Additionally, there is a
difficulty in finding a suitable site for reference electrode
placement on the ventral (front) surface of the body where the skin
is more sensitive to electrical stimulation, especially those
associated with repetitive stimulation to one site. Also, if the
clinician forgets to remove the reference electrode from the back
of the body while treating muscles on the front of the body or the
chest, a trans-thoracic current may be induced and adversely affect
heart rhythm.
SUMMARY OF THE INVENTION
[0010] With the foregoing in mind, the present inventor recognized
that there is a need for a bipolar stimulator probe, wherein the
active stimulator electrode and the reference electrode are
provided as part of a single tool, and the separation between the
electrodes is fixable at a set, e.g., standardized, distance which
is significantly greater than the electrode separation of known
bipolar stimulator probes and bipolar bar electrode configurations.
As a general principle, to obtain large force twitches and to
simulate the monopolar stimulating condition with the bipolar tool,
the distance between the active and reference electrodes should be
spaced far apart as possible. Ideally, the two electrodes could be
spaced as far apart as possible (perhaps by 2-3 feet or more), but
it may not be clinically practical to have this type of very wide
spacing provided by a bipolar electrode tool. Such a device may be
too heavy, bulky, and /or awkward for practical use. Also, the
uneven contours of the intervening tissues may prevent the
reference electrode from touching the skin surface. For practical
utility, an electrode spacing of 15-16 cm (6 inches) may be
provided between the stimulating and reference electrodes. However,
it is advantageous to have an option for increasing or decreasing
the spacing between the two electrodes. The probe tool may be
configured to permit adjustment of the fixed relative position of
the electrodes within a given range, such as by slideable or
otherwise movably mounted electrodes similar to the principle used
in a sliding gauge such as a Vernier caliper. A bipolar probe tool
providing a wide spacing between the two electrodes will
approximate the effect of monopolar stimulation with a separate
reference electrode, with the electrical stimulus producing less
pain to the patient compared to bipolar stimulation where the two
electrodes are spaced apart by only 2-4 cm or less. The ability to
reduce the inter-electrode distance is essential for treating small
muscles in the face, hands and feet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a diagrammatic depiction of a bipolar stimulation
probe in accordance with the invention.
[0012] FIG. 1a is a diagrammatic depiction of a variation on the
FIG. 1 embodiment, with the handle moved to one end of the tool
(Vernier caliper-style).
[0013] FIG. 2 is a diagrammatic depiction of a further bipolar
embodiment stimulation probe tool.
[0014] FIG. 3 is a diagrammatic depiction of a further exemplary
probe tool in accordance with the invention.
[0015] FIG. 4 is a diagrammatic depiction of yet another exemplary
probe tool embodiment.
[0016] FIG. 5 is a perspective view depicting a prototype probe
tool in accordance with the invention, corresponding to the
diagrammatic representation of FIG. 1.
[0017] FIG. 6 is a perspective view of another prototype probe tool
in accordance with the invention, corresponding to the diagrammatic
depiction of FIG. 3.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0018] Referring now to the appended drawings, FIG. 1 is a
diagrammatic depiction of a bipolar stimulation probe 1 in
accordance with the invention. Handle 2 is preferably about 3-6''
or so in length. Wires 3 lead to the two spaced electrodes 5, 7 of
the probe tool, and connect to a suitable stimulator/recording
device, such as the commercially available electrical stimulation
unit, Model DS 7, from Digitimer Limited (Herforthshire, England).
As illustrated, electrode 5 may be the stimulating electrode, and
electrode 7 may be the reference electrode. Electrodes 5, 7 are
mounted on the ends of spaced arms or prongs 9, 11, attached to
each other by a connection cross member 12, which may extend
between the stimulating prongs 9, 11 at right angles to the prongs,
as shown in FIG. 1. Prongs 9, 11 preferably have a length of about
2.5'' (50 mm) and are spaced from each other to provide a
separation of distance "A" between electrodes 5 and 7, which is
preferably at least 6'' center to center, and with an upper limit
of 24-36''. Electrodes 5, 7 may be of a known type. For stimulation
applications, the electrodes may be covered by a wad of wet cotton
or wool soaked in water, but it is preferable to use hypertonic
9-10% saline to facilitate electrical conduction. The stimulating
electrodes can be provided in the form of disposable felt pads
manufactured for SA-ETOIMS. They can be pre-packaged already
pre-soaked or immersed in hypertonic 9-10% saline to facilitate use
in treatment. For recording purposes, the recording surface is made
preferably with stainless steel or another known conductive
metallic surface of suitable type.
[0019] A trigger button may be mounted on probe tool 1, to permit a
clinician to conveniently activate the probe for stimulation
applications. The switch is preferably touch-sensitive, activated
by a pressure on the patient contact surface of the stimulating
electrode or activated by a push-button on the handle, on its side
or end, for on/off control triggered by the clinician. The probe
may also be activated via a separate hand button that can be
triggered by the patient or another person.
[0020] The stimulating probe should be light-weight, preferably
weighing about 2-4 oz or less, e.g., preferably the approximate
weight of a writing pen. However, the materials used for the
connection cross member 12 should be sturdy enough to withstand
breakage upon being subjected to repetitive use and receiving
significant impacting forces along the attached prongs from the
forceful twitches. The circumference of the handle or stem 2 of
probe 1 is preferably about 4 cm, or on the order of the diameter
of a writing pen, for ease of grasp and comfort for the clinician.
Handle 2 preferably has a length of 3-6 inches to avoid wobbling of
the electrodes on the surface of the skin by virtue of hand
movements. Alternatively, instead of a stem-like handle, the
connection cross member 12 may also be of a thickness that can
allow it to be used as a handle in the same fashion commonly in use
with steam irons (see FIG. 2, discussed below). Also, the handle
may be placed at one end of the connection cross member 12, similar
to the handle of a Vernier caliper. This is illustrated in FIG. 1a,
wherein the tool has a repositioned handle 2'. In such a design,
the handle may be tilted up at an obtuse angle relative to the
connection cross member 12 (as commonly seen in the handle of a
frying pan or sauce pan), such that the handle will, in use, avoid
touching the patient's skin and muscle tissue. Such a handle is
shown in dotted lines in FIG. 1a (labeled 2''). The handle should
be of a girth comfortable for gripping for long periods of time.
The control for changing the inter-electrode distance can be
suitably placed on the handle for thumb manipulation. The control
may be a wheel or button that can also lock-in the chosen
inter-electrode distance. Both electrode surfaces in contact with
the patient will preferably be circular in shape and have a
diameter of 1-2 cm.
[0021] FIG. 2 is a diagrammatic depiction of a further embodiment,
probe tool 13, wherein the spaced electrode mounting structure is
provided in the form of an arched/semi-lunar shaped arm 14, with
the active and reference electrodes 5, 7 mounted on the ends, e.g.,
with a spacing "A" of about 6''. This embodiment also has a handle
2, as in the first embodiment, which attaches to a central portion
of arm 14. Stem-like handle 2 may be omitted, in which case the
arched/semi-lunar shaped arm 14 can be used as the handle with a
girth comfortable for prolonged gripping, similar to that of a
steam iron.
[0022] On uneven body regions, the stimulation and reference
electrodes may not be able to easily reach to touch the skin
surface simultaneously. Simply re-positioning the stimulating
electrode in treating these areas can overcome this difficulty.
Also, fashioning the connector piece between the active and
reference electrodes to be in the shape of an arc or semi-lunar
shape, as shown in FIG. 2, will help with this issue, by fitting
better over the contour of a muscle. Also, the probe arms could be
made movable or bendable to permit the probe ends to reach to touch
the skin surface. This concept is similar to that of the flexible
stem of a reading lamp that can be bent to supply the optimal angle
for providing the correct amount of light for reading. The probe
device arms and handle should be made of, or shielded by, plastic
or other insulative material to electrically isolate the
stimulation and reference electrodes and prevent a short of the
electrodes or electrical impulses passing to the clinician.
[0023] FIG. 3 is a diagrammatic depiction of a further exemplary
embodiment, probe tool 15, wherein the spaced electrode mounting
structure is provided in the form of an essentially flat bar 16, to
which the active and reference electrodes 5, 7 may be mounted,
directly, or in very short arms or prongs, e.g., with an arm length
of 0.5'' or less, and an inter-electrode spacing of about 6''. This
embodiment also has a handle 2, as in the first embodiment, which
attaches to a central portion of flat bar 15. This type of bar
electrode is more suitable for recording or stimulation purposes
over flat and even surfaces. Probe tool 15 is not so well suited
for use where there is a need for rapid search and location of
large force twitch sites in performing SA-ETOIMS therapy. This is
due to the short length of the prongs of the bar electrode that
interfere with placement of both electrodes in contact with the
skin surface over contoured muscles.
[0024] FIG. 4 is a diagrammatic depiction of yet another exemplary
embodiment, probe tool 17, wherein the spaced electrode mounting
structure is provided in the form of a pair of arms 19 which
converge to form an obtuse angle. Similar to the previous
embodiments, the active and reference electrodes 5, 7 may be
mounted on the end of the arms, e.g., with an inter-electrode
spacing of about 6''. This embodiment also has a handle 2, as in
the first embodiment, which in this case attaches to the central
apex portion of the structure formed by the angled (converging)
arms 19.
[0025] SA-ETOIMS.TM. related advantages potentially realizable a
wide-spaced bipolar probe tool in accordance with the invention are
described below.
[0026] The bipolar probe tool allows SA-ETOIMS.TM. treatment to be
performed faster since bi-manual work is not required of the
clinician as with the monopolar stimulation method that requires
moving the stimulating electrode, in addition to the separate time
and attention required to move the reference probe during the
treatment procedure.
[0027] The paired movement of the reference electrode together with
the active stimulating probe prevents any one site over which the
reference has been placed, from prolonged excessive stimulation and
unnecessary discomfort to the patient.
[0028] Having a fixed or limited adjustable distance between the
stimulator and the reference electrodes allows the reference
electrode to be in the same area of the muscle treated and the
stimulus is localized to the one muscle of interest. This stimulus
isolation to one muscle is possible in treating large muscles of
the buttock and lower limbs. The stimulus can also be isolated to
one side of the body since both stimulus and reference electrodes
can be moved together for performing such purposes. This
substantially eliminates the possibility of accidental placement of
the reference electrode on the back of the body while treating
muscles on the front of the body, and the attendant risk of
inducing trans-thoracic current that can interfere with heart
rhythm.
[0029] With the bipolar probe tool, there need only be one cable
leading to the stem of the tool, making the tool more user friendly
by avoiding the need for two separate wires extending to separate
reference and stimulator electrodes. This avoids the entanglement
of wires during treatment and leads to better utilization of
treatment time.
[0030] The present inventor has used prototype probes similar to
those depicted in FIGS. 5 and 6 to provide SA-ETOIMS treatments
with a fixed interelectrode distance of 15-16 cm or 6'' and found
the electrode spacing to be sufficient to allow large force
twitches to be elicited. The treatments with such a probe is
faster, more efficient and decidedly less painful at the reference
site compared to monopolar stimulation using static reference
electrode placement. With certain muscles, such as the buttocks of
overweight patients, in certain instances, this spacing may not be
sufficient to elicit large force twitches. This situation can be
overcome by a slideable or otherwise moveable mechanism to increase
the distance between the active and reference electrodes to more
than 6'' and possibly up to 24''-36'', or more. Such an arrangement
can be used to facilitate the positioning of the bipolar probe such
that the active stimulation electrode is positioned on the muscle
of interest, and the reference electrode is positioned to lie on a
different muscle. This advantageously simulates monopolar
stimulation conditions to a great extent, due to the wide spacing
distance between the two electrodes. A slidable movement of the
electrodes along the cross-arm 20, to adjust the electrode spacing,
is diagrammatically depicted by arrows B.sub.1 and B.sub.2 in FIG.
5. Flexible joints, allowing the cross-arm 20 to bend in order to
reposition/reorient the electrodes, are diagrammatically depicted
at 21. Also depicted in FIG. 5 is a handle-mounted user activated
push-button 23 that may be associated with a trigger switch of the
tool, as previously described. (The illustrated slidable movement,
flexible joints and push-button are optional features not present
in the prototype probes used by the inventor.)
[0031] The bipolar probe devices of the present invention also have
utility beyond their advantageous use for SA-ETOIMS.TM. stimulation
purposes. Such devices can also be used for other stimulation
procedures, wherein it may be necessary or desirable for the
reference and active electrodes to be widely spaced apart, or in
situations wherein it is desired to simulate monopolar stimulation
conditions for stimulating nerve and/or muscle.
[0032] This same type of probe can also be used for recording
compound muscle action potentials and sensory nerve action
potentials for performing nerve conduction study (NCS) recordings,
using an electromyographic (EMG) machine. For motor nerve
conduction studies with recording from large muscles, the active
electrode is placed over the motor point of the muscle of interest
and the reference electrode is placed over the tendon of the
recorded muscle or in an electrically inactive region such as the
bone on which the tendon of interest inserts. Similarly, for
recording sensory nerve action potentials, the active and reference
electrodes are placed over the line of distribution of the sensory
nerve.
[0033] In order to obtain better electrical readings for recording
procedures, the probe electrodes that are placed in contact with
the patient's skin are preferably made of metal or other disposable
metallic conducting material, such as those routinely used in
electrocardiographic (EKG) and nerve conduction study (NCS)
recordings, instead of the disposable wet felt pads that are
preferably used for stimulating purposes. The active and reference
leads of the tool will preferably be of a compatible type that can
fit into the appropriate receptacles of the pre-amplifier of the
EMG machine. The spaced electrode pairing provided by the present
invention is useful in facilitating the search for the best motor
point from which to record for a given muscle. This is due to the
ease in repositioning the recording and reference electrodes, and
the use of a fixable or standardized distance between the two
electrodes. When the spacing between the active and reference
electrodes is not held constant (fixed), the shape and amplitude of
the recorded potential changes in relationship to the distance
between these two electrodes; this variability is especially
notable with sensory nerve action potentials recordings. The bar
electrode style probe as shown in FIG. 3, is suitable for recording
of sensory and muscle action potentials.
[0034] It will be understood that while the invention has been
described in conjunction with various embodiments and details
thereof, the foregoing description and examples are intended to
illustrate, but not limit the scope of the invention. Numerous
other variations and arrangements are within the scope of the
invention.
* * * * *