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Individuals may experience reduced ranges of motion between the various
joints of their body as a result of physical injury or other infirmity.
Changes in the range of motion including increases and decreases thereof
are relevant to the evaluation of recovery or disability and therefore
accurate measurements of the range of motion of the various joints of the
body are critical.
In the prior art, the range of motion of the various joints of the body was
measured through the use of a manually operated goniometer merely
consisting of two straight members, for example, metal rulers, pivoted
together at the center of a graduated semi-circular protractor-type
device. Such a goniometer was used through the manual placement thereof on
a joint of the body with one of the rulers parallel with one bone of the
joint and the other of the rulers parallel to the other bone of the joint.
The operator of this goniometer would then move the moveable ruler in
correspondence with movement of one of the bones with respect to the other
bone through the maximum range of motion thereof as permitted by the
patient's particular condition. Thus, the location of the moveable ruler
with respect to the angular scale of the goniometer would yield a reading
of the actual range of motion. Of course, this method and means for
measuring the range of motion has severe limitations in accuracy and ease
of use since improper alignment of the device or inadvertant movements of
the operator's hand may result in angular readings having an error of
10.degree. or more. Since a severe accident may reduce the range of motion
in a particular joint by less than 10%, the above described margin of
error for the prior art goniometer is within the range of loss of motion
and is therefore a device having sufficient inaccuracy so as to render it
virtually unusable as an accurate medical measuring tool.
In 1977, the American Medical Association published a publication entitled
"Guides to the Evaluation of Permanent Impairment" as a tool to assist in
evaluating or rating permanent disabilities related to changes in range of
motion. Therein, a method is set forth in determining the present range of
motion which method is believed to have a shortcoming by failing to
adequately explain how a neutral point is determined. Further, for
example, on page 42 of the AMA publication, a method for measuring ranges
of motion in the cervical spinal region are described which are extremely
subjective in nature both in the measuring technique and evaluation
thereof.
Therefore, in light of the AMA publication and the shortcomings of the
prior art goniometer as explained hereinabove, a need has developed for a
measuring instrument able to measure the range of motion of the various
joints of the body to within an error of 1% or less. Such an increase in
accuracy would be beneficial not only for the treating and evaluating
doctors but would be of equal important to other medical fields such as
physical therapy, occupational therapy and rehabilitation, wherein the
therapist places the patient on an exercise program requiring a
predetermined number of repetitions of movements of a joint at a minimum
predetermined range of motion. Such a device would also have great
commercial applications in the field of sports medicine, evaluation of
insurance claims, in industrial hiring situations, in military personnel,
as well as in arbitration and litigation proceedings.
With these goals in mind, the predecessor to the present invention was
invented and disclosed in the above listed parent U.S. application Ser.
No. 521,925 filed Aug. 10, 1983, now abandoned. Therein, a range of motion
measuring device was disclosed with the goal of increasing the accuracy in
the measurement of the range of movement of the various joints of the
body. As disclosed therein, one embodiment included a goniometer
consisting of a movement sensitive gear system used in conjunction with an
infrared light system to sense movements, react to those movements and
measure the movements with increased accuracy. In a further embodiment
disclosed therein, a shaft encoder was used in determining the absolute
angle with this device having a pendulum attached to the shaft which
remained vertical while the housing rotated along with the moving limb of
the joint being measured. In a further aspect of the invention disclosed
in the parent application, a relatively basic potentiometer arrangement
was employed. In each of the above described embodiments, a micro-computer
accepted encoded data from the goniometer and calculated an absolute
difference between the current position and the beginning position called
the "gravity reference position" . The absolute difference of this
calculated figure was then displayed on a digital readout and preserved in
the internal memory of the micro-computer for subsequent printing upon a
paper roll as desired.
In the invention described in the above referenced patent application, the
embodiment utilizing a potentiometer as the goniometer utilized a standard
off the shelf potentiometer (FIG. 4) having an elongated rotatable shaft
to which was rigidly connected a pendulum having a weight. Thus, as the
casing thereof rotated, the weight would tend to maintain a vertical
position with respect to the center of the earth due to gravity forces
which would then rotate the potentiometer shaft yielding a voltage output
therefrom which could be interpreted so as to define the range of motion
accrued. This potentiometer operated goniometer was simple in construction
but was not specifically designed for the use to which it was put and
therefore had severe drawbacks. Firstly, the potentiometer was not
designed to rotate based upon the movement of a housing with respect to a
stationary weight. The potentiometer was specifically designed to have a
knob attached to the shaft thereof on which could be exerted a large force
to thereby rotate the shaft and adjust the resistance. Accordingly, the
rotary motion of the shaft along with the weight when the housing was
turned with respect thereof, was not found to be sufficiently smooth so as
to result in the desired degree of accuracy thereof. Furthermore, the fact
that the potentiometer was a separate entity installed into a housing as
manufactured made the inventive goniometer extremely large and cumbersome
and thereby unusable to any degree with small joints such as those between
bones of a finger or a toe, for exampIe. Thus, it was concluded that a new
electronic goniometer would have to be developed which was compact and
lightweight and usable to measure the range of motion between any two
joints of the body regardless of size.
In another aspect, the prior art was found lacking when it came to
providing a device enabling the close monitoring of the range of motion of
various joints of the body during the performance of repetitious
exercises. A physician would prescribe for a patient a series of sets and
repetitions of a particular exercise, and although the patient would
perform the exercises, the patient would not perform them through the
prescribed range of motion and accordingly, such exercises would prove to
be useless in the rehabilitation of the patient. Thus, a device was needed
which could measure sets and repetitions of exercises performed on various
joints of the body while requiring that the joints be exercised through
the prescribed minimum range of motion.
SUMMARY OF THE INVENTION
Thus, in order to overcome the above described deficiencies and
shortcomings found in the prior including the prior art as embodied in the
invention disclosed in the patent application, the present invention was
devised as a means of advancing the state of the art significant steps
forward from the state of the art as embodied in the invention disclosed
in the parent application. Thus, the present invention includes the
following features;
(a) The present invention includes a newly designed electronic goniometer
which overcomes all of the deficiencies found in the prior art designs.
The electronic goniometer is of the resistance type and includes a small
lightweight preferably plastic casing having an inner chamber of a
substantially circular periphery. On the periphery of this chamber is
mounted an extremely thin resistor film formed in an elongated strip and
extending over most of the circumference of the chamber. The resistor
film, in the preferred embodiment, is made of a highly mechanically
oriented carbon material with uni-directional crystals therein. Rotatably
mounted within the chamber is a pendulum device having an extremely small
wiper contact at the bottom thereof. Two contact wires are provided for
the electronic goniometer one of which attaches to the resistor film and
the other of which is electrically connected to the wiper contact. Thus,
as the housing moves with respect to the pendulum which maintains a
vertical orientation with respect to the center of the earth, the wiper
contact moves along the resistor film thereby defining a resistance which
varies with the movement of the housing with respect to the pendulum. This
resistance may be converted to a voltage which is inputted into the
micro-computer contained in the modular housing of the present invention.
The pendulum bearings are of sufficient quality so as to enable the
pendulum to freely swing even if the housing is tilted up to 70.degree. in
a direction perpendicular to the direction of rotation of the pendulum.
(2) The modular housing of the present invention includes a mode switch
enabling the choosing of a range of motion mode or a bio-feedback mode.
The modular housing further includes a display, a tape printer, a set of
buttons enabling the choosing of a direction of motion, a set of buttons
enabling the choosing of the type of examination and a set of buttons
enabling the inputting of numerical entries such as those relating to sets
and repetitions of exercises to be performed when the mode switch is in
the bio-feedback position. A reset switch is also provided to enable the
device to be reset after each measurement sequence has taken place.
Further, a digital display is provided so as to enable displaying of the
various measured ranges of motion thereon.
Within the modular housing is housed a micro-computer which is the heart of
the present invention and which has connected thereto electronic circuitry
enabling the micro-computer to receive signals from the above described
electronic goniometer which signals may be converted into angles which may
be displayed, retained in a computer memory and/or printed out by the
printing unit. The modular housing further includes a software input which
enables different computer programs to be interfaced with the
micro-computer to thereby add flexibility to the invention. Further, the
modular housing includes a plurality of cord connections which enable a
plurality of electronic goniometers to be simlutaneously connected thereto
so that special measurements such as those relating to the range of motion
of one vertebral joint with respect to another vertebral joint may be
undertaken.
(4) The present invention may be utilized in one of two modes, a first mode
wherein particular ranges of motion of particular body joints may be
accurately measured and a second mode wherein a partciular joint may be
exercised through a predetermined sequence of repetitions and sets with
each repetition being made through a predetermined range of motion. In
this mode, the micro-computer monitors the range of motion through which
the joint travels during the exercises and only indicates that a
repetition has been completed when the prescribed range of motion has been
attained.
(5) In a further aspect of the present invention, the modular housing may
include an input connection enabling the connection thereto of a remote
control enabling the freezing of a range of motion reading for retention,
display and/or printing. In a further aspect, the inventive electronic
goniometer may include in its casing hardware enabling the display thereon
of the particular measured range of motion, enabling resetting of the
goniometer and enabling the freezing of a reading, as well as enabling
control of the activation thereof.
(6) the above described software may include aspects thereof which program
the invention so that different printouts for the printing mechanism may
be obtained. For example, printouts may be obtained through the software
programming of active ranges of motion, degrees of flexion, repetitions
and sets of particular exercises which exercises are also printed for
reference, etc. The present invention as embodied in the modular housing,
the one or more goniometers, the software which may be inputted thereto
and the remote control freeze button may be completely self contained
within a suitcaselike container which enables the invention to be easily
packed up and transported to its point of use.
Accordingly, it is a first object of the present invention to provide a
device enabling the measurement of the range of motion of various joints
of the human body to within an accuracy of .+-.1.degree.-2.degree..
It is a further object of the present invention to provide a device
enabling the recording of sets and repetitions of exercises performed by
the various joints of the body during the rehabilitation thereof.
It is a further object of the present invention to provide a device wherein
any measurements, sets and repetitions measured thereby may be displayed,
stored and/or printed out on paper mounted therein, preferably in roll
form.
It is a yet further object of the present invention to provide such a
device including a lightweight compact electronic goniometer which is
sufficiently small and lightweight so as to enable its attachment to any
joint of the human body for measurement of the range of motion thereof.
It is a yet further object of the present invention to provide such an
electronic goniometer which may, if desired, include a display thereon as
well as controls therefor.
It is a still further object of the present invention to provide a device
which may be programmed as desired through the selective attachment
thereto of diverse preprogrammed cassettes, each of which programs the
micro-computer thereof to perform unique predetermined functions.
It is a still further object of the present invention to provide a device
wherein a plurality of electronic goniometers may be attached thereto so
as to simultaneously measure relative ranges of motion of different body
joints simultaneously, such as different adjacent joints of the spinal
column.
It is a still further object of the present invention to provide a device
which may be easily packed up and transported to its point of use in a
convenient packaging scheme.
These and other objects, aspects and features of the present invention will
be better understood from the following description of the preferred
embodiments when read in conjunction with the appended drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic representation of the human body with goniometers
in accordance with the present invention attached to various ones of the
joints thereof for range of motion measurements.
FIG. 2 shows a block diagram of inputs and outputs in a representative
micro-computer for the present invention.
FIG. 3 shows a schematic electrical circuit depicting the micro-computer
and associated connections.
FIG. 4a and b show a flow chart of the operation of the present invention.
FIG. 5 shows a perspective view of one embodiment of the goniometer of the
present invention with the cover removed to show detail.
FIG. 6 shows an exploded view of the electronic goniometer depicted in FIG.
5.
FIG. 7 shows a side view of the pendulum and wiper contact of the inventive
electronic goniometer.
FIG. 8 shows a perspective view of a further embodiment of the electronic
goniometer of the present invention.
FIGS. 9 and 10 show representative print outs which may be obtained from
the present invention in different modes of operation thereof.
FIG. 11 shows a schematic depiction of the modular housing of the present
invention.
SPECIFIC DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1 of the drawings, the present invention includes an
electronic goniometer 10 which may selectively be attached at various
locations on the human body so as to enable measurements of the range of
motion of the various joints thereof. As shown in FIG. 1, the electronic
goniometer 10 is attached to the skull by virtue of an elastic band 11.
Further, electronic goniometers 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h,
10i, 10j, 10k, 10l, 10m, 10n, 10o and 10p are also shown connected to
various portions of the body in some cases by corresponding elastic
members 11.
With reference now to FIGS. 5-7, it is seen that the inventive electronic
goniometer 10 includes an outer casing 13 having an inner chamber 15
defined by substantially circular peripheral walls 17. The casing 13
includes a back wall 19 connected to a peripheral wall 21 which defines
the substantially circular outer periphery of the inner chamber and a
cover 23 which is removeably attached to the sidewall 21.
As best seen with reference to FIGS. 5 and 6, the wall 17 of the chamber 15
has mounted thereon a resistor film 25 which is made of an extremely thin
film of highly mechanically oriented carbon with uni-directional crystals
therein, which resistor film 25 is extremely sensitive to electrical
current. The resistor film 25 extends over the major portion of the
circumferences of the walls 17, preferably over 256.degree. of the
circumference at least, so as to give the electronic goniometer 10
increased flexibility in orientation. Connected at one end to the resistor
film 25 is a contact wire 27 which is extended through an opening 29
formed in the wall 21 of the casing 13.
The back wall 19 of the casing 13 has rigidly mounted thereon a shaft 31
which extends virtually across the entirety of the width of the wall 17.
If desired, the shaft 31 may be sufficiently long so that it enters an
opening (not shown) in the cover 23 for purposes of stability. In view of
the lightweight nature of the component parts of the electronic goniometer
10, such additional shaft mounting structure is not necessary. At the end
of the shaft 31, a pendulum 33 is mounted which includes a collar portion
35 having a bearing 37 therein which allows the collar 35 to be mounted
over the shaft 31 while allowing easy rotation of the pendulum 33 with
respect thereto. The bearing 37 is of sufficient quality so as to enable
the pendulum 33 to freely swing even if the casing 13 is tilted up to
70.degree. in a direction perpendicular to the direction of rotation of
the pendulum 33.
If desired, the bearing 37 may comprise a ball baring or if desired, may
comprise any kind of bearing so long as frictional forces between the
bearing 37 and the shaft 31 are kept at an absolute minimum.
The pendulum 33 further includes a neck portion 39 which connects the
collar 35 to a weight 41. On the underside of the weight 41, a wiper
contact 43 is provided which is made of a flexible wire-like member which
is designed to resiliently engage the resistor film 25 as the housing 13
moves with respect to the pendulum 33 which maintains a position with
respect to the center of the Earth as close to vertical as is possible
depending upon the particular orientation of the casing 13, due to the
force of the Earth's gravity.
As best seen with reference to FIG. 7, the collar 35 includes a recessed
area 45 into which is mounted a wiper contact 47 which is connected to a
wire 49 extending out of the casing 13 through the hole 29. The pendulum
33 is made of an electrically conductive material so that when the device
is assembled as shown in FIG. 5, an electrical connection is made between
the wire 27, the resistor film 25, the wiper contact 43, the pendulum 33,
the wiper contact 47, and the wire 49. Thus, as the position of the casing
13 varies with respect to the vertical position of the pendulum 33, the
resistance as defined between the position of the wiper contact 43 on the
resistor film 25 and the wire 27 correspondingly varies. Thus, as this
resistance varies, in a correspondingly manner, the voltage across the
wires 27 and 49 with a steady source of electrical power connected
thereacross also varies in a predictable and measureable manner.
Reference is now made specifically to FIGS. 2-4, wherein a general and
specific explanation of the internal electronics of the present invention
will be made. Firstly, reference is made to FIG. 2 which shows a block
diagram of the inputs and outputs for the micro-computer of the present
invention. As shown in FIG. 2 schematically, a micro-computer 100
comprises the heart of the system. The electronic goniometer 10 is seen to
emit a voltage output 101 which output is received by an analog-to-digital
converter 103 which converts the analog voltage signals 101 into a digital
form compatible with the circuitry of the micro-computer 100. The line 105
carries theses binary encoded pulses to the micro-computer 100.
Additionally, a box labeled 10a-p is seen to be connected to the
analog-to-digital converter 103 via a voltage line 101, 101'. The box
labeled 10a-p is provided so as to represent a plurality of additional
electronic goniometers 10a-p as depicted in FIG. 1 of the drawings, which
additional electronic goniometers may as desired be connected into the
system. Additionally, a box labeled 107 is shown to connect to the line
105 via a further line 109. The box 107 is shown to represent a freeze
button which may be selectively actuated to freeze the reading of the
goniometer 10 or 10a-k at whatever reading exists at the moment at which
the freeze button is depressed. The line 109 is tapped into the line 105
so as to represent the fact that the freeze button stops further
transmissions from the analog-to-digital converter to the micro-computer
upon the actuation thereof so as to freeze whatever reading has been
received by the micro-computer at that moment.
With further reference to FIG. 2, it is seen that operating system software
designated by the reference numeral 109 may be selectively plugged into
the micro-computer 100 so that various unique programs may be utilized to
control the micro-computer in predetermined ways. Further, the control
panel switches are designated by reference numeral 111 which control panel
switches communicate in binary form with the micro-computer 100 via the
line 113.
Again, the reference numeral 100 refers to the microcomputer which forms
the heart of the system shown in FIG. 2. The micro-computer 100 comprises
a micro-processor circuit that operates under the control of the software
109 so as to interpret the binary encoded angles sent thereto in the line
105 and to store the true angles in the memory unit designated by
reference numeral 115. The storage memory unit is used by the
micro-computer 100 to store the current angular reading as received by the
line 105 and also to store whatever sequence of measurements is to be made
as inputted by the control panel switches 111 and so as to further
identify whichever switches on the control panel have been depressed
during the present operational cycle. Also shown in FIG. 2 is an
arithmetic unit 117 which is utilized by the micro-computer 100 to
calculate the number of degrees of movement of the electronic goniometer
10 with respect to an established reference point. The established
reference point is determined immediately before the angle is measured by
depressing a "zero" key on the control panel 111 as will be described in
greater detail hereinafter.
As further shown in FIG. 2, an output line 119 is provided from the
micro-computer 100 with a first branch 121 thereof leading to a digital
display unit 123 which, in the preferred embodiment, comprises a series of
light emitting diodes, designated by reference numeral 125. A second
branch 127 of the line 119 leads to a paper printer unit 129 which may
print a permanent record of the examination results as represented by
reference numeral 131 and as described in greater detail hereinafter. The
actuation of the paper printer unit 129 may be selectively accomplished by
depression of the appropriate buttons on the control panel 111 or may be
auotmatically accomplsihed at some point during an examination sequence.
Reference is now made to FIG. 3 which shows the details of the system
depicted in FIG. 2 in the form of an electrical circuit. FIG. 3 shows a
single electronic goniometer 10 connected to the analog-to-digital
converter 103 via an analog multiplexer 102. The analog multiplexer 102 is
provided with one input port A for the goniometer 10 and a further input
port B for an additional electronic goniometer as explained hereinabove.
Of course, if desired, the analog multiplexer 102 may have as many input
ports as necessary to connect however many electronic goniometers are
required depending upon the measurements which are to be conducted. The
analog-to-digital converter 103 is connected to the micro-computer 100 via
a line 106 having bridged thereon a latch device 112 which is provided to
take the asynchronous output of the analog-to-digital converter 103 and
capture it and retain it therein for later reading by the micro-computer
100.
As further shown in FIG. 3, a decode logic device 114 is provided which
arbitrates between the various devices which are connected to the
micro-computer as to which device will talk to the micro-computer 100 at
any given instant. Thus, the decode logic device 114 prevents bus
contention. FIG. 3 also shows in electrical schematic form the freeze
button designated by reference numeral 107 and also shows the zero button
designated by reference numeral 108 which was briefly described ablove.
The zero button 108 is provided so that in virtually any orientation of
the electronic goniometer 10, if the zero button 108 is depressed, the
electronic goniometer 10 will be considered to be reading zero degrees in
that orientation so that further movement by the electronic goniometer 10
will result in range of motion readings which are taken with respect to
the precise position of the electronic goniometer when the zero button 108
was depressed.
FIG. 3 further shows the printer 129 and the LED display device 123, 125.
Other aspects of the circuitry which are shown in FIG. 2 such as for
example the storage memory unit 115, the arithmetic unit 117, the
operating system software 109 and the control panel switches 111 are not
shown in FIG. 3 for reasons of clarity.
Reference is now made to FIG. 11 wherein an example of one configuration of
the modular housing described hereinabove is shown. The modular housing
150 is generally seen to include a large number of buttons and switches
which were previously designated by the general reference numeral 111. As
seen in FIG. 11, these buttons are divided up into several separate
related areas of function. Thus, a first block of buttons 151 includes a
series of buttons 153 each of which when depressed indicates to the
micro-computer 110 that a specific joint of the body is to be measured.
Examples of these joints are: interphalangeal, metcarpophalangeal,
metatarsophalangeal, carpometacarpal, distal interphalangeal, proximal
interphalangeal, thumb, index, finger, mid-finger, ring finger, little
finger, wrist, elbow, shoulder, great toe, second, third, fourth and fifth
toe, ankle, knee, hip, cervical, dorso lumbar. A further block of buttons
155 includes further buttons 157 each of which when depressed indicates to
the micro-computer 100 that a particular direction of motion is to be
undertaken in the joint chosen in the block of buttons 151. Examples of
directions of motion which may be indicated through depression of one of
the buttons 157 are as follows: inversion, eversion, flex, extension,
abduction, adduction, supination, pronation, rotation, lateral bend left
and right, dorsi flex, palmer flex, radial div, ulnar div, plantar flex,
etc.
As further shown in FIG. 11, a further block of buttons 159 is provided
which includes therein a plurality of buttons 161. The block of buttons
159 includes buttons which relate to examination control. Thus, when one
or more of the buttons 161 are depressed, the following pieces of
information are fed to the micro-computer 100 as to a type of examination
which is contemplated: (1) ankylosis, a condition of a joint in which the
movements are restricted by malfunction, malformation or union of bones;
(2) active motion, the motion of a joint without assistance from an
outside party; (3) passive motion, motion of a joint with the assistance
of an outside force such as a therapist or machine, etc.; (4) amputate,
the absence of body part that normally would have a range of motion; (5)
lag, indicating that there is a negative lag due to disability; (6) left,
indicating that examination is being undertaken with the particular joint
indicated on one of the buttons 153 located on the left side of the body;
(7) right, indicating that the joint indicated on one of the buttons 153
is that which is located on the right side of the body. Additionally,
other buttons 161 may be provided in the block of buttons 159 to indicate
to the micro-computer 100 an event goal which is utilized as will be
explained in greater detail hereinafter when the present invention is used
in a biofeedback mode. Further, a print button may be provided in this
block of buttons 159 to instruct the computer to print the result of the
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