U.S. patent number 3,834,374 [Application Number 05/241,635] was granted by the patent office on 1974-09-10 for diagnostic electrical scanning.
Invention is credited to Minas Ensanian.
United States Patent |
3,834,374 |
Ensanian |
September 10, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
DIAGNOSTIC ELECTRICAL SCANNING
Abstract
Body surface bioelectrical potentials are determined and
recorded by use of a stationary electrode in contact with the body
surface and an exploratory electrode which comprises a rotatable
element, that preferably carries an electrolyte. Scanning of the
body surface along a continuous path or over an area is carried out
by rolling at least one exploratory electrode over the said
surface, thus permitting mapping of the potentials along the line
or over the area contacted by the exploratory electrode, whereby
abnormalities of the skin or portions of the body under the skin
may be detected.
Inventors: |
Ensanian; Minas (Eldred,
PA) |
Family
ID: |
22911525 |
Appl.
No.: |
05/241,635 |
Filed: |
April 6, 1972 |
Current U.S.
Class: |
600/397;
600/547 |
Current CPC
Class: |
A61B
5/332 (20210101); A61B 2562/0217 (20170801) |
Current International
Class: |
A61B
5/0404 (20060101); A61B 5/0402 (20060101); A61b
005/04 () |
Field of
Search: |
;128/2.6E,2.6G,2.6R,2.1B,2.1E,2.1R,2.1Z,404,405,410,411,417,DIG.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kamm; William E.
Attorney, Agent or Firm: Harlan, Jr.; Ashlan F.
Claims
I claim:
1. A process for recording bioelectrical potentials in a living
body which comprises establishing electrical contact between the
body surface and a first electrode through an electrolyte which
forms a portion of a solid rotatable element, said element having a
continuous circular periphery, establishing electrical contact
between the body and a second electrode at a point on the body
removed from said first electrode, maintaining said electrical
contacts with the body surface while rolling said element in a
continuous path along said surface without leaving a substantial
deposit of electrolyte on said surface, and continuously recording
the potential between said electrodes.
2. A process as set forth in claim 1 comprising repeatedly rolling
said first electrode along said path and continuously recording the
potential between said electrodes during each of the retracings of
said path.
3. A process as set forth in claim 1 comprising rolling said first
electrode along a plurality of closely adjacent paths on the body
surface and continuously recording the potentials between said
electrodes in the movement of said first electrode along each of
said paths.
4. A process as set forth in claim 1 in which a plurality of said
first electrodes is employed, each being electrically connected
through a recording device with said second electrode, comprising
continuously recording the potentials between each of said first
electrodes and said second electrode along the paths on the body
surface taken by said first electrodes.
5. A process as set forth in claim 1 in which said electrolyte is
in gelled, self-sustaining form.
6. A process as set forth in claim 1 in which said electrolyte is
NaCl.
7. A process as set forth in claim 1 in which said electrolyte is
in gelled, self-sustaining form.
Description
BACKGROUND OF THE INVENTION
This invention relates to a process for dynamically measuring and
recording bioelectrical potentials on the body surface and to
mapping the body surface or portions thereof with respect to such
potentials.
Electrical measurements are commonly employed in diagnosis of heart
and brain conditions and disorders. Electrocardiograms are
routinely used to detect cardiac lesions and other cardiac
abnormalities. Electroencephalograms which reflect the activity of
the brain are widely used in the examination of patients having
brain tumors and lesions. In both cases electrical currents
generated in the respective organs are recorded and the recorded
wave patterns are interpreted by comparison with other recordings.
The recording is accomplished by determining the generated
potentials between a plurality of electrodes applied to the body
surface at predetermined points or between two or more electrodes
at least one of which is successively applied to different points
on the body surface.
SUMMARY OF THE INVENTION
It has been discovered that with apparatus that is much less
complicated than that previously used in obtaining
electrocardiograms and electroencephalograms bioelectrical
potential readings can be obtained by scanning along a line or over
an area of the body surface. Such readings in many cases provide
meaningful data as to the condition of the skin and underlying
organs or other portions and may permit diagnosis of body
conditions. The potential readings can be taken continuously along
a path on the body surface using only two electrodes. Apparatus
suitable for determining the body surface potential according to
the invention is disclosed in copending U.S. patent application
Ser. No. 79,033, filed Oct. 8, 1970.
The present process consists in feeding the continuous electrical
potential reading obtained between two electrodes to a suitable
recording instrument such as a strip chart recorder. One of the
electrodes is stationary and in contact with the body at a suitable
location. The second or exploratory electrode comprises a rotatable
element which is rolled over a predetermined path on the body
surface, the variations in potential along the path of the
electrode being shown as a continuous line or trace on the recorder
chart. Obviously, when the exploratory electrode is moved with
substantially constant speed there is a virtual one to one
correspondence between points along the recorded trace and points
on the skin along the path of the electrode that can be readily
used to determine the potential at any such point on the skin.
Changes in the potential along the path of the exploratory
electrode are indicative, not only of changing skin resistance but
also of the electrical activity of organs and other body portions
beneath the skin. Preferably the rotatable element of the
exploratory electrode carries an electrolyte to ensure good skin
contact. It will be understood, however, that the velocity of the
rolling electrode does not affect the potentials measured.
Potential mapping of an area of body surface can be accomplished by
successive use of the same exploratory electrode along different,
closely adjacent portions thereof or by using a plurality of
exploratory electrodes simultaneously.
SHORT DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially schematic view of apparatus suitable for
carrying out the present invention;
FIG. 2 is an enlarged, detail view of a portion of the exploratory
electrode shown in FIG. 1;
FIG. 3 is a sectional view on line 3--3 of FIG. 2;
FIG. 4 is a simulation of typical oscillatory scanning
patterns;
FIGS. 5 to 19, inclusive, are drawings showing the essential
features of the scanning patterns or traces recorded in carrying
out scannings on various portions of a body surface as described
hereinafter; and
FIG. 20 is a partially schematic view of a modified form of
apparatus.
DESCRIPTION OF THE INVENTION
As pointed out above, the present invention provides a diagnostic
method which by scanning the electrical potential of the body
surface, i.e. continuously determining such potential along a path
on the skin, establishes the location of certain conditions or
abnormalities on or under the skin. In the following examples a
number of possible uses for the method are set forth.
Apparatus suitable for carrying out the method of the present
invention is disclosed in copending U.S. patent application Ser.
No. 79,033, filed Oct. 8, 1970. In FIGS. 1-3 of the drawings of the
present application there is illustrated an embodiment of such
apparatus which comprises a pair of electrodes, one of which has a
rotatable element that carries an electrolyte to insure good
electrical contact with the skin and the other of which is adapted
to be held in stationary contact with the skin, a strip chart
recorder, and an electrical conductor between each of the
electrodes and the input terminals of the recorder. In the
illustration in FIG. 1, a scanning is being taken on the forearm of
a subject.
More specifically, in FIG. 1 there is shown a recorder 21 having
input terminals 23 and 25. Attached to the terminal 23 by a
suitable electrical conductor such as a wire or cable 27 is an
electrode 29 which is preferably formed of metal and may have any
desired shape or structure to permit it to be held in contact with
the body surface. To the other input terminal 25 there is attached
by a suitable electrical conductor such as a cable or wire 31 an
exploratory electrode comprehensively designated 33, details of
which are shown more clearly in FIGS. 2 and 3. Preferably, the
conductive wires or cables are provided with electrical shielding.
The electrode 33 comprises a stem or shank portion 35, to which the
wire 31 is preferably attached and an axle portion 37 which extends
laterally from the shank portion. The outer part of the axle
portion is reduced in diameter, thus forming a shoulder 39. The
electrode 33 also has a rotatable element which comprises a wheel
having a hub 41, preferably formed of metal, on which there is
suitably secured a conductive tire 43 formed of a gelled
electrolyte solution. The wheel is rotatably mounted on the reduced
portion of the axle 37 between the shoulder 39 and a removable
retaining member such as a ring 45 that is snapped into a groove
adjacent the outer end of the axle 37. An electrically insulating
handle 47 is provided on the shank portion 35 of the exploratory
electrode 33. The numeral 49 designates a strip chart produced by
the recorder and bears a line representing electrical potentials on
the surface of the arm along the path followed by the rotatable
element of the electrode 33. As depicted in FIG. 1, the exploratory
electrode 33 is being rolled along the forearm 51 of a subject and
the stationary electrode 29 is clipped to said forearm.
It will be understood that the rotatable element of the electrode
33 can take other forms and be mounted in other ways. Thus, for
example, there may be used, instead of the electrode shown, one
constructed as shown and described in the above-mentioned copending
application, in particular, the structures illustrated in FIGS. 9,
10 and 13 of the drawing of said application. The said figures and
the descriptions thereof are hereby incorporated herein by
reference.
Those skilled in the art will understand that strip chart
recorders, such as are preferably employed in carrying out the
present invention, are capable of adjustment in a variety of ways.
Not only can the chart speed be changed, but also the sensitivity
and, for example by reversing the leads to the electrodes, the
polarity. The chart ordinarily has a center line indicating zero
potential (denoting at 0 in FIG. 1) and the recording pen draws on
one side or the other thereof, depending upon polarity, at a
distance from the zero potential line proportional to the received
voltage. Since, however, the sensitivity can be adjusted, the
actual distance from the zero potential line of a point on the
recorded line or trace responsive to a specific voltage will be
greater or less depending upon the sensitivity range chosen for the
recording.
It will also be understood that the amplitude and frequency of the
electrical impulses and currents occurring in the body which result
in different skin potentials vary and that the skin is known to act
as an antenna, picking up electrical radiation. Consequently, the
width of the trace drawn by the oscillating pen of the recorder
will vary. In FIG. 4 there are shown four sections of a strip chart
53 which illustrate the effect on the trace width of skin
resistance. Progressing from section a of the chart to section d
thereof, the skin is shown to have decreasing resistance. In
section a the skin resistance is quite high, while in section d it
is quite low. A relatively wide trace on the chart will also be
obtained when one or both of the electrodes is not in contact with
the body surface since in such case stray alternating current
fields are picked up and recorded. The actual width of traces drawn
on the recorder will be determined both by the voltage and the
sensitivity thereof. It should be remembered that where the trace
is relatively wide, the potential indicated is that of a point
midway between the parameters of the trace. In many instances, the
chart speed is too slow to show the trace as oscillations so that
the trace on the chart appears as a solidly inked area without
visible oscillations. In the reproductions of the recorder chart
portions hereinafter referred to, the wider traces are for
convenience arbitrarily shown with horizontal lines that represent
such oscillations.
In carrying out diagnostic procedures by the present method, the
location and type of the stationary electrode is not usually
important. It may be held in the fingers of the subject, may be
clipped to the body, or may be held or clamped to the body with or
without a suitable electrode paste to improve electrical contact
with the body surface.
EXAMPLE 1
For this example a plurality of tests were made which demonstrate
that non-visible alteration of the skin surface cen be detected and
recorded by the novel method of the invention.
In each test a small amount of a corrosive liquid was placed on the
skin of the forearm of a subject, the arm being immobilized and
resting against a background chart having ruled lines thereon which
permitted the location of the liquid application to be established.
The liquid was removed from the skin by thorough wiping and the
skin was then allowed to dry. After drying, no evidence of the
treatment was visible to the eye. Then, using apparatus
substantially like that illustrated in FIG. 1, the wheel of the
exploratory electrode was run over the arm from wrist to elbow
while the stationary electrode was firmly grasped in the other
hand. It was observed in each test that, as the exploratory
electrode passed over the area on which the corrosive liquid had
been placed, there was a sudden marked increase in the recorded
potential which decreased again to the normal voltage after the
rolling electrode had passed over the treated area.
Tests were made with dilute NH.sub.4 OH solution and dilute
HNO.sub.3 solution. In each case the trace on the recorder chart
located the treated area on the arm of the subject as determined by
comparison with the rulings on the background chart. FIG. 5 is a
reproduction of an area A on the recorder chart showing the
deviation from normal potential over the treated skin area when
dilute nitric acid was used.
It will be evident from the foregoing that victims of accidents
involving the spilling or spraying of corrosive materials may be
easily treated for latent burns or skin damage by using the present
novel method to locate the affected and potentially damaged areas
of the skin.
One of the simplest determinations or diagnoses that may be made by
the present novel method is a determination as to whether muscles
are relaxed or in tension. This is illustrated in the following
example.
EXAMPLE 2
Using apparatus substantially like that illustrated in FIG. 1,
tests were made on an arm of a subject. The stationary electrode
was in contact with the hand of the subject. The exploratory
electrode was run longitudinally of the arm of the subject from the
wrist area to the biceps area while the arm was relaxed and resting
on a table. The trace on the recorder chart showed that the
potential throughout the length of the path on the arm was almost
constant, there being a potential difference along the path of only
about 50 mv. When, however, the arm muscles were tensed by the
subject, a reading taken while rolling the exploratory electrode
along the same path on the arm showed a difference in potential of
about 150 mv from the wrist to the biceps. FIGS. 6 and 7 are
reproductions of the portions of the recorder chart showing the
varying potentials with the arm muscles of the subject relaxed and
tensed, respectively.
The following is another example of the location of a latent injury
to the body by use of the method of this invention.
EXAMPLE 3
In this test, using the same general technique as that described in
the preceding examples, a recorded potential line or trace was
obtained with the rolling exploratory electrode from the forearm of
a subject while the arm was resting on a table. Then, without
warning to the subject, a hot heat lamp was brought into momentary
contact with the forearm. Another potential line was immediately
recorded by rolling the exploratory electrode over the same path on
the arm. Substantial reproductions of the potential lines or traces
obtained before and after the burn are shown, respectively, in
FIGS. 8 and 9. At the time of making the second recording, there
was no visible evidence of the burn on the arm. Subsequently, a
severe burn became evident in an area of the subject's arm
corresponding to the region B of the trace shown in FIG. 9.
As will be seen in comparing FIGS. 8 and 9, the normal trace varied
little in potential, only about 100 mv, while the trace obtained
after application of the heat lamp was irregular, varying several
hundred mv in potential, and showed extensive oscillation over a
considerable region on each side of the region B.
Still another example of the location of latent injury to the body
is set forth in the following example.
EXAMPLE 4
Using substantially the same technique as that described in
Examples 2 and 3, a normal potential line or trace was obtained on
the recorder by running the exploratory electrode along the relaxed
forearm of a subject. A substantial reproduction of this trace is
shown in FIG. 10. It indicates a change in skin potential of only
about 60 mv from the wrist to the inner elbow. A sharp, hard blow
with a wooden rod was then given on the arm. Another trace over the
same skin path was recorded after the blow was inflicted. The
second trace showed a potential variation of over 400 mv and
considerable oscillation. This second reading is substantially
reproduced in FIG. 11. Although a bruise subsequently was
observable on the subject's arm at a point thereon corresponding to
the region designated C in FIG. 11, potential changes over the area
struck were clearly evident before the bruise could be seen.
As shown in the following example, the method of the present
invention may also be used in studying and locating abnormalities
in the circulatory system of the body.
EXAMPLE 5
In this example there is set forth a test for detecting restricted
circulation in the arm of a subject. For test purposes such
restricted circulation was produced by a tourniquet applied to the
upper arm of the subject.
Substantially the same procedure as that described in Example 1 was
used. FIG. 12 is a substantial reproduction of the trace or
potential line recorded, when the exploratory electrode was run
from the wrist to the upper arm of the subject, with the arm
relaxed. FIG. 13 is a substantial reproduction of the line or trace
obtained along the same path immediately after a soft rubber tube
as a tourniquet was applied to the upper arm and tightened. FIG. 14
is a reproduction of the trace obtained along substantially the
same path after the tightened tourniquet has been in place for
approximately one minute. Application of the tourniquet to the arm
with the resultant reduced blood circulation is clearly evident in
the recorded traces, the relaxed arm trace showing a substantially
constant potential and a rapid change (see FIG. 13) occurring when
the tourniquet is tightened. Even after a quite short interval of
reduced circulation, the recorded trace (FIG. 14) is very
irregular, showing much oscillation.
The following example sets forth still another use of the method of
the invention in locating the site of an injury to the body.
EXAMPLE 6
FIGS. 18 and 19 substantially reproduce the traces obtained by the
present novel method before and after, respectively, making a small
puncture in the forearm of a subject. The left arm of the subject
was rested on a table and, with the arm relaxed, a recording was
made by rolling the exploratory electrode from the wrist region to
the inner elbow region. The stationary electrode was held in
contact with the left hand of the subject. A fine puncture was then
made in the skin of the forearm and another recording was
immediately made by passage of the exploratory electrode over
substantially the same path as before. Although the puncuture was
not visible to the eye, the second recording indicated its location
by the deflection in the trace indicated at D in FIG. 19. It will
be noted that in FIG. 18 the potential along the line of travel of
the exploratory electrode is rather constant, varying only about 65
mv while in FIG. 19, after the puncture was inflicted, the trace is
of greater amplitude and the potential varies as much as about 300
mv.
It will be evident from the foregoing example that the present
method may be put to practical application in locating slivers of
metal or nonconductive materials, e.g. glass, in the skin even when
the skin surface shows no visible sign of the point of entry
thereof.
From the foregoing examples, it will be obvious that the scope of
use of the present novel process is quite wide. Other possible
diagnostic uses of the process will be discussed below. It is not
to be understood, however, that all such possible uses are
discussed or even mentioned, since the field of potential or
desirable use is extremely broad inasmuch as the present method may
be used on any part of the body.
As pointed out earlier herein, electrocardiograms are important in
determining the condition of the heart and diagnosing abnormalities
thereof. It is known that the heart is not usually oriented in a
perfectly vertical position in the body. Consequently, the
electrical axis or zero potential plane of the heart's electrical
field is not the same in all persons. Moreover, such axis is known
to be subject to change as a result of damage to the myocardium and
for other reasons. It is, therefore, often important to determine
the electrical axis. This can be easily and very quickly done by
the process of the present invention.
In the normal, known method of determining the electrical axis of
the heart, six electrodes disposed at different points on the chest
are required. The varying potentials detected by these electrodes
are recorded by a plurality of pens on a strip chart recorder and
the recorded data is interpreted and analyzed. By the method of the
present invention, however, to determine such axis it is only
necessary to run the exploratory electrode across the chest of a
subject in two or more spaced, parallel paths. When the electrical
axis is crossed there is a reversal of the direction of the spikes
which represent the pulses of the heart beat on the recorded lines
or traces. This reversal of polarity indicates a transition by the
electrode from the positive half of the heart's electrical field to
the negative half thereof. Consequently, the electrical axis can be
determined by connecting the points on the chest of the subject
which correspond to the points on the recorded traces where the
polarity reversal of the heart beats take place. The resultant line
is the electrical axis.
FIGS. 15 and 16 are substantial reproductions of portions of a
recorder chart showing traces typical of those produced by the
present process, the letter E indicating the pulses of the heart
beat and the letter F indicating the region corresponding to chest
areas proximate to the zero potential plane of the heart. In making
the recordings from which FIGS. 15 and 16 were drawn, the
stationary electrode was connected to the left ankle of the
subject. Obviously the heart's location can be determined by
comparing the traces obtained by running the exploratory electrode
along a plurality of body paths in the proximity thereof including,
if desired, paths on the back and sides of the subject.
It will be evident that the use of an exploratory electrode in
accordance with the present method for determining the location and
orientation of the heart is faster and easier than the conventional
procedure. In many cases this is highly important since delays in
obtaining information about the heart often are factors
contributing to the death of a patient.
Another use for the method of this application is the determination
and recording of the electrical activity of the brain. As in the
conventional way of producing electrocardiograms,
electroencephalograms are conventionally obtained by the use of a
number of electrodes. These are applied at various locations on the
shaven head of a subject. It has been found that by attaching a
stationary electrode to one ear of a subject and running the
exploratory electrode across the subject's forehead brain waves can
be easily recorded on a strip chart recorder. Obviously, this
procedure is less time consuming and simpler than shaving the
subject's head and applying a plurality of electrodes thereto. FIG.
17 is a substantial reproduction of a typical wave recording
according to the present method. It will be obvious that scanning
with a rolling electrode can also be carried out over any other
desired portion of the head, indeed a potential mapping of the
entire head surface can be readily obtained; and that from the
resulting recorded traces abnormalities of the brain, such as
tumors, can be located.
As indicated above, it may be desirable or necessary for study or
diagnosis in some instances to determine the body surface potential
along a plurality of related lines on such surface. This is
illustrated in FIGS. 15 and 16 which show the traces obtained by a
pair of parallel passages of an exploratory electrode made to
locate the electrical axis of the heart. Where parallel paths are
desired, a plurality of exploratory electrodes 33, according to the
invention, may be, as shown in FIG. 20, mounted together in a unit
61, each electrode being connected by a suitable lead 31 to a
separate input terminal and pen of a strip chart recorder so that
two or more traces can be made at once. In other cases, it may be
desired to have the paths followed by the exploratory electrodes
intersect. For example, in FIG. 14 the potential reversal
designated by the letter G, where the trace crosses the line of
zero potential on the chart, indicates the crossing of the pulse or
arterial pressure point in the wrist of the subject. When the exact
location of this point is required, one or more additional traces
obtained by rolling the exploratory electrode over the same region
will pinpoint the location. As previously pointed out, the
potentials at many different points over specific body areas can be
mapped by covering such areas with multiple scannings by one or
more exploratory electrodes, either successively or
simultaneously.
It will be understood that the traces showing body surface
potentials obtained by carrying out the present method reflect not
only the skin potential but also the electrical pulses of organs,
nerves, muscles, and other body elements beneath the surface which
are superimposed thereon. Indeed, if desired, the method can be
employed to pick up and record electrical currents impressed on the
body, for example, those used in electroanesthesia and
electroanalgesia. Such currents will also be superimposed on the
traces of skin potentials.
As pointed out above, the construction of the electrodes employed
in carrying out the present process may vary within wide limits.
The exploratory electrode, however, must have a rotating element
that rolls over the body surface and preferably such element
carries an electrolyte solution to ensure good electrical contact
with the skin. The size of the rotating elements can vary as
desired although generally it is preferred for increased accuracy
to have both the diameter and the width or thickness thereof
relatively small. For example, a roller about 7 mm thick and having
a diameter of about 25 mm has been found quite satisfactory.
The pressure employed on the exploratory electrode in carrying out
the present method may also vary. Differences in pressure may cause
quantitative changes in the recorded potential lines or traces, but
not qualitative ones. However, it is desirable to use light
pressures since this will minimize any skin or muscle reaction to
passage of the electrode. In most cases a pressure of about
10g/cm.sup.2 is satisfactory although less pressure can be used if
desired. In recording body surface potentials that are to be
compared or in potential mapping of a body surface, it is of course
important to employ the same pressure on the exploratory electrode
and preferably the same velocity of scanning in the several
scannings made. It has been found that under substantially similar
circumstances and external conditions the traces obtained on the
strip chart are reproducible for the same subject and that similar
types of traces are obtained when subjecting different subjects to
the same stimuli or events.
In carrying out the method of the present application, at least
that portion of the exploratory electrode which contacts the body
surface or is separated therefrom only by the electrolyte solution
is preferably of silver although any other common metal can be
used. When a gel of an electrolyte solution is employed, sodium
chloride is preferred as the electrolyte since it is
physiologically neutral, but other harmless salts can be used. A
satisfactory gel can be produced by forming a solution of 0.5 g
NaCl and 14 g of gelatine in sufficient water to form 100 ml of
solution. The solution is then allowed to set in molds of the
desired shape and mounted on or used as the rotatable element of
the electrode. It is generally desirable to have the electrolyte on
the rolling element of the exploratory electrode in such form as to
prevent or minimize the leaving of a deposit of electrolyte on the
body surface during scanning in which electrical contact between
the electrode and the body surface is made through the
electrolyte.
It will be evident from the foregoing description that the method
set forth in this application is of use in a wide variety of
circumstances and has great value in determining and diagnosing
body conditions. It will also be evident that there are many
possible variations of the described procedure that can be used
either to obtain information of the type herein described or other
information as to body conditions and functioning.
* * * * *