Note: Descriptions are shown in the official language in which they were submitted.
~2~5~
BIOFEEDBACK SYSTEM
BACKGROUND OF THE INVENTION
This invention relates to a biofeedback system particularl~
useful in rehabilitation therapy. The invention relates, mor~
particularly, to a biofeedback system suitable in the treatment
of motor neuron lesions particularly in the retraining of muscles
and reeducating patients who have suffered strokes or have be~
subjected to neurologic trauma.
A recent summary of biofeedback techniques appears in an
article of Basmajian, John V., MD, "Biofeedback in
Rehabilitation: A Review of Principles and Practices", Arch. of
Physical Medicine and Rehabilitation, Volume 62, No. 10, pages
469-475, October 1981. The article describes known techniques of
using electronic equipment to reveal to patients and therapists
certain physiologic events and to teach patients to control
events by manipulating the event related signals, which usually
are visual and/or acoustic. Biofeedback has gained recognition
especially in the treatment of upper motor neuron lesions,
particularly in retraining muscles and inducing relaxation of
muscles of stroke patients and the like. The broad concepts of
using eIectrogoniometers, pressure-sensitive and position-sensing
devices as transducers is recognized.
Another summary, S.J. Middaugh, "Electromyographic Feedback:
Effects on Voluntary Muscle Contractions in Normal Subjects",
Arch. of Ph~sical Medicine and Rehabilitation, Volume 63, No. 6,
pages 254-259, June 1982, recognizes the possibility of using a
voltage controll~d oscillator producing a tone which is related
to electromyographic feedback as an improvement in simple
trial-and-error-learning.
"
~ mong body and limb position sensiny devices are usllally
switches such as disclosed in the U.S. Patent No. 3,614,76~ to
~annuzzi entitled "Prone Position Alarm", issued October 19,
1~71. The mercury switch is positioned within a housing "hich
also includes an audio oscillator which sounds an alar~, the
housing being operatively associated with a clip ~hich may be
placed on a user's belt. Another proposal for the use of a
mercury switch in association with a limb position sensing device
is known from the U.S. Patent No. 3,885,576 to Symmes entitled
"Wrist Band Including A Mercury Switch To Induce An Electric
Shock", issued May 27, 1975.
Of more general interest, are the teachings in the U.S.
Patent Nos. 4,191,949 and 3,208,062 to Myers and Gregory,
respectively, these patents disclosing respectively a position
warning device, associated with an otherwise conventional belt,
and a signal device for alerting a user to the nodding of his
head.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to provide a
biofeedback system which is especially useful in rehabilitative
therapy and is simple, versatile and inexpensive.
Another object of the present invention is to provide a
biofeedback system which allows a therapist to intervene in the
system in a demonstrative way, while engaged in rehabilitative
therapy and the like.
An additional object of the present invention is to provide
a biofeedback system which allows a patient to effect a series of
; actions and receive specific, distinct biofeedback signals for
each respective action, and to repeat the series of actions.
The foregoing objects, as well as others which are to become
clear from the text below, are achieved in accordance with the
present invention by providing a bio~eedback system which
~6S~
includes a plurality of switches, for example mercury s~itches,
which can be positioned on a patient's body and operatively
arranged to respond to changes in orientation or position of a
body member such as, for example, a patient's hand, wrist and
forearm. Circuitry is arranged to respond to the closing o~
respective ones of the switches and develop specific, aistinct
biofeedback signals, for example individual audible and visual
signals for respective switch closings.
BRIEF DESC~IPTION OF THE DRAWINGS
Figure 1 is a pictorial drawing of an exemplary sensing
device which can be attached to a patient and incorporated into a
biofeedback system according to the present invention.
Figure 2 is a cross sectional view of a portion of the
sensing device of Figure 1, the section being taken along section
line 2-2, and showing the position of a mercury switch within the
housing portion of the sensing device.
Figure 3 is a cross sectional view similar to that of Figure
2, showing a modified version of the mercury switch arrangement
of Figure 2 in which four contacts rather than two are utilized
and which can be incorporated in the biofeedback system of the
present invention.
Figure 4 is an additional modified mercury switch
arrangement similar to that of Figure 3 in which two pair of
contacts are provided, and which may be used in the biofeedback
system according to the present invention.
Figure 5 is a pictorial view of a housing within which the
circuit components of the present invention, other than those
contained in the sensing devices, may be positioned, signal
lights and a loud speaker grille being visible.
Figure 6 is a schematic, block diagram illustrating an
exemplary embodiment of a signal processing circuit which
126S2~4
constitutes a major portion of the biofeedback system according
to the present invention.
Figure 7 is a sirnplified diagram of the back of the housing
shown in Figure 5, switch-board apertures, into which male plugs
may be placed, being visible as well as exemplary connections
between some of the apertures of suitable plugs in the form of
jumpers also shown in Figure 6.
Figures 8A-8E are respective pictorial illustrations of a
patient's right arm with a number of sensing devices positioned
and which are to aid one in understanding the operation of the
biofeedback system according to the present invention.
GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in Figure 2 a conventional mercury switch referred
generally by the numeral 10 which may be utilized in practicing
the present invention includes a substantially cylindrical glass
member 11 having its lowermore end closed by an integral extension
of the glass member 11, a pool of mercury 12 being shown thereat.
The other end of the cylindrical glass member 11 is closed by a
suitable insulating plug 13, which may be made of plastic or the
like. A pair of conductive leads 14, 15 extend through the
insulating plug 13 into the interior of the glass member 11, the
free ends of these conductive leads 14, 15 constituting an open
circuit which would be closed were the pool of mercury 12 in
contact therewith.
The ~onductive leads 14, 15, suitably covered with
insulation, are spaced apart and are partially encapsulated
within the insulating plug 13. The insulation, which may enable,
extends over those portions of the leads 14, 15 which extend to
the outside of the switch 10. The leads 14, 15 are positioned on
the outside of the cylindrical glass member 11 and thereafter are
ben~ upwardly extending through a hollow-cylindrical metallic
~26S~4
sleeve 16 which is fixed centrally and extends through a ~nurled
knob 17. A protective insulation sleeve 18 extends over the
insulated leads 14, 15.
Referring to Figures 1 and 2, the knurled knob 17 is
provided on its outer surface with a visible vertical mark 20 ana
is movably positioned over a circular member 21 having indicia
22, for example degree marks, at fixed intervals on a portion
thereof near its periphery. The circular member 21 is fi~edl~
positioned as a closure member over the top of a cylindrical
member 23, which is closed at its bottom and is provided with a
pair of ring members 24 which extend ~rom near the bottom of the
cylindrical member 23 and through which a flexible band 25
extends. The flexible band 25 is provided at its free ends with
~elcro so that the free ends may be brought into contact and
fixedly hold itself fast. It is to be appreciated that other
conventional techniques or members can be provided for closing
the flexible member 25 so as to position the sensing device shown
in Figure 1 about the wrist, arm, hand or other body member of a
therapist or patient, as the cases may be. The flexible
protective insulation sleeve 18 extends upwardly from the knurled
knob 17 with the insulated conductive leads 14, 15 inside the
same, terminating within a plug 26 having its connections within
a cylindrical housing 27 which has extending therefrom
conv~ntional male contacts 28, 30 insulated from one another and
which are in conductive contact with the conductive leads 14, 15
as they terminate within the housing 27.
As particularly visible in Figure ?, the mercury switch 10
is carried beneath inner surface of the circular member 21 by a
circular flange 31 which extends outwardly from the cylindrical
member 16. A suitable washer 32 or the like is positioned about
the cylindrical member 16 immediately below the inner surface of
the circular member 21 and spaced from the flange 31. A spring
or the like (not shown for the ~lake of simplicity), is positioned
between the washer 32 and the circular flange 31 so as to hold
~s~
the sleeve 16 and the mercury switch 10 in position so ~ha~ fhe
mercury switch 10 can be rotated by manually manipulating the
knurled knob 17, the mark 20 on the outside of the knurled kn~b
17 indicating the relative position of the lo-.7ermore end of the
cylindrical member 11 at any given time.
Two variants of the mercury switch are illustrated in
Figures 3 and ~, respectively, as being positioned within
respective cylindrical member 23, which correspond to the mem~er
23 shown in Figure 2 corresponding parts of that portion of the
respective sensing devices of Figures 3 and 4 are provided with
the same reference numerals used in ~igures l and 2. In Figure 3
two pair of contacts 32a, 33b are provided in respective ends of
a V-bent cylindrical member lla, an insulating plug 13a and 13b
being pro~ided in the respective ends of the member lla. In
Figure 4 two pair of contacts 32c and 32d are provided in
respective ends of an inverted V-bent cylindrical member llb. In
this case insulating plugs 13a and 13d are provided in respective
ends of the member llb.
The signal of processing circuitry of the present invention
is preferably housed within plain-looking console, a suitable
configuration for such a console being illustrated pictorially in
Figure 5. As shown in Figure 5, the front of the console
includes a vertical, rectangular panel 35, a backwardly slanted
panel 36, and a second, relatively narrow, vertically extending
panel 37. Centrally located on the sloping panel 36 is a grill
work 38 behind which a loudspeaker is positioned. The console is
provided with side panels, the right-side panel 40 being visible
in Figure 5. Out of sight of the patient, so as not to distract
the patient, is a female plug 41 into which a male plug
associated with a pair of earphones could be inserted were one to
decide not to utilize the loudspeaker behind the grill work 38 as
the audio biofeedback signaling device, electing instead to use
the earphones. Visual biofeedback devices are constituted by a
pluraliky of lamps positioned longitudinally behind the
~2fi~
rectangular panel 37 and viewable through apertures therein, the
lamps constituting the distinctive, different colored light
sources illustrated as lamps 42-47 which are respectively
associated with filters to provide the differing colors. As
illustrated, the lamps in the order named provide distinct color
outpu-ts, 42-47 these colors could he for example, orange, yellow,
green, blue, purple and white as indicated by the letters O, Y,
G, B, P, and W, respectively, beneath the lamps on the panel 37.
It is preferable, nevertheless, that the letters do not appear
beneath the respective light sources so as not to unnecessarily
detract a patient from the visual stimuli from the distinctive,
color light sources 42-47. A seventh viewable color source 48 is
visible to a patient, this seventh light source being constituted
by a further lamp with filter behind the panel 35 and indicated
as being a red source by the letter R appearing on the panel 35.
Here again, it is preferable that the letter R not appear on the
panel so as to be viewable by the patient and thus serve as a
possible distraction to the patient.
The console includes a longitudinal top panel 50 and a
downwardly sloping back panel, as can be discerned by viewing an
edge 51 thereof where the back panel meets the side panel 40.
Signal processing circuitry is illustrated in Figure 6
suitable for practicing the present invention. As connected in
Figure 6, the circuitry is arranged so as to provide audible and
visual biofeedback signals to a patient in response to six
distinct motions of the patient, who may for example, be a stroke
victim undergoing retraining in the use of his forearm, wrist and
hand, and who may have some right-left confusion. For purposes
or illustration, the body movements could be constituted of l)
flexing of a forearm, 2) extending of a forearm, 3) grasping of a
hand, 4) release of a hand, 5) supination of a wrist, and 6)
pronation of a wrist, respectively.
-- 7 --
~2~52~)~
As illustrated in Figure 6, six mercury switches which are
to be strapped to a patient are shown schematicall~, respecti~rl~
as swi-tches 5G-55, which would during treatment be remsvabl~
fixed to the patient by strapping sensing devices, such as shown
in Figures 1-4 to the patient. As a practical matter one would
select one or the other o~ the switches shown in Figures 2-~ for
the switches to be attached to a patient. The Fiyure 2
arrangement being especially suitable for the ~orearm, the Figure
3 arrangement for the wrist and the Figure 4 arrangement for the
hand or fist.
As a possible further feature of the invention, in a
preferred form, the circuitry of Figure 6 is provided with six
additional switches 56-61 which would be removably fixed to the
therapist in the same fashion and at corresponding locations as
those associated with the patient so the therapist can
demonstrate the desired movements resulting in the same visual
and audible biofeedback signals which the patient would produce
were the patient properly to move his arm, for example, in the
fashion and in the sequence which the therapist wishes the
patient to do.
Before turning to the details of the over-all circuitry
shown in Figure 6, one channel thereof will first be described.
The mercury switch 50 is positioned electrically between a
voltage source indicated as B+, and a point of refe~ence voltage,
illustrated as being ground, the switch 50 being connected
between B~ and ground via a resistor 62. Also connected between
~+ and ground, via the same resistor 62, is the mercury switch 56
which is to be strapped to the therapist. The ungrounded end of
the resistor 62 is connected, via a jumper 63, to the start
terminal of a conventional electric or electronic timer 64, which
also is provided with a resetting input and a manually operable
set input, illustrated diagrammatically as a push button 65 ~Yhich
resets the timer 64 by grounding a point thereof. The timer 64
is also provided with a push button switch 65' which when
-- 8 --
~5%~1
depressed places the timer 64 in an ready condition, awaiting ~
set or resetting input signal. The timer 64 has two outputs, one
being constituted by a terminal connected by a jumper 66 to the
input of a driver 67, which in turn has its output connected in
energizing relationship to the solenoid of a relay 68 which
includes two pairs of contacts 70, 71 which are closed whenever
the relay 68 is energized. As illustrated, a voltage source
indicated as A+ is connected, via a variable resistor 72, tG one
side of the orange-light source constituted lamp 42, the other
side of the lamp 42 being connectable to ground via the pair of
contacts 70, upon energization of the relay 68. The second pair
of contacts 71 of the relay 68 are connected in series with a
tone generator 73 to the A+ source. Accordingly, whenever the
relay 68 is energized, the pair of contacts 70 and the pair of
contacts 71 close, causing respectively the orange-light emitting
lamp 42 and the tone generator 73 to be energized. The variable
resistor 72 can be manipulated by the therapist or the patient to
provide for either dim or bright lighting of the orange-light
emitting lamp 42, thus providing different intensities for the
visual feedback signal which it provides. The tone generator 73
has an output which is preferably constituted by a particular
musical tone or other pleasant sound is connected so as to
energize a speaker 74 or a pair of earphones 75. As illustrated
the output of the tone generator 73 is fed to the speaker 74
and/or the earphones 75 via a volume control potentiometer 76 so
that the volume of the audible biofeedback signal can be varied,
as it is adjusted by the therapist or the patient.
The timer 64 also is provided with a second output, which,
as is to be explained below, is used to set the next timer in a
series of timers, res~ective ones of the timers being associated
with respected motions to be undertaken by the patient.
As indicated above, the six channels in the illustrated
embodiment are of substantially identical construction, the
52~4
second throuyh six channels being shown respectively within
dashed lines blocks 78-82, respectively. Each of the channels
78-82 include respective resistors 83-87 arranged like the
resistor 62 with respect to the respective mercury switches
51-55, which are to be associated with the patient, and mercur~
switches 57-61, which are to be associated, i~ desired, with the
therapist. The channels 78-82 as connected includ~ respective
jumpers 88-92 and 88'-92', respective timers 93-97 as well as
respective drivers 98-102 and respective relays 103-107. The
respective relays 103-107 include respective pairs of contacts
108, 109 and 110, 111 and 112, 113 and 114, 115 and 116, 117.
The even numbered ones of these contacts are operatively
connected to the A+ voltage source, via the adjustable resistors
72a-72e so as to energize respectively the distinct light
emitting lamps 43-47 when the respective relays 103-107 are
energized. It is to be understood, however, that each of the
lamps 43-47 could be connected to the A+ terminal via the
variable resistor 72, which also connects lamps 73 to the A+
terminal were all lamps to be dimmed at the same time and to the
same extent. Similarly, the odd-numbered ones of the pairs of
contacts relatively connected to the A+ voltage source via
respective musical tone generators 118-122 which produce
respectively distinct, preferably musical tones or distinct
pleasant sounds which one can hear from the speaker 74 or
earphones 75.
Xespective signal channels 69 and 78-82 are intercoupled by
connecting the reset input of the respective timers 64 and 93-97
to the setting output of the respective timers 97, and 93-96,
these interconnections being shown and being provided via
respective jumpers 128 and 123-127.
The signal processing system of Figure 6 desirably includes
additionally a seventh channel 129 which electrically is somewhat
less complex than the channels 69 and 78-82. The seventh channel
includes a resistor 130 which has one end grounded and the other
-- 10 --
,.
~26~2~4
band connected to the voltage source B+ via six micros~"i~ches
illustrated as switches 130-137. The switches 131-137 are
mercury switches which are, for example, removably fi~ed to the
other arm of a patient at points corresponding to the placement
of the microswitches 50-55. The purpose of the mercur~ switches
131-137 is to provide, when they are respectively closPd, an
error-signal constituted by the appearance of a voltage across
the resistor 130 which is fed, via a jumper 138 to a driver 140
which in turn upon receipt of an input signal energizes the relay
141 closing two pairs of contacts 142, 143, respectively which in
turn energize the red light lamp 38 and the tone generator 144
which, unlike the tone generators 73 and 118-122 produces a
preferably non-musical sound which provides a special biofeedback
to the patient which indicates to him that he has moved the wrong
arm, for example. Dimming for the lamp 48 is provided by the
variable resistor 145.
Turning briefly to Figures 8A-8E, and with further reference
to Figure 6, a brief discussion of the operational sequence is to
be considered.
Once the patient and/or therapist has the six mercury
switches 50-55 or 56-61, as the cases may be, positioned on his
arm, wrist and hand as illustrated, the circuit of Figure 6 is
made ready by setting the first timer 64 in enabled conditioniby
pressing the push button switch 65. It is to be assumed that all
of the o~her timers 93-97 are not yet set, each having been
placed in a ready, that is unset, condition by, for example,
depressing the respective push bu~tons 144 to 148 or having run
down as a result of previous use without having been reset.
The patient then undertakes to move his arm, fist and wrist
in a predetermined instructed sequence. For example, he first
flexes his forearm moving it from the position as shown in Figure
8A to that shown in Figure 8B, this motion closes the mercury
switch 50 which is within the cylindrical member 23a and starts
12~
the time~ 64 running for a predetermined length of time, for
example, two or three .seconds. The output from the timer 64 is
~ed to the driver 67 which drives the relay 68, causing the pair
of contacts 70 and the pair of contacts 71 to close thereby
energizing the orange light emitting lamp 42 and the tone
generator 73 which are respectively seen and heard by the
patient. ~t the conclusion of the two or three second period of
audible and visible feedback, the timer 64 emits a second output
signal, which serves to reset the timer 93, making it ready to
accept a start signal. The patient then returns his forearm to
the position shown in Figure 8C which closes the mercury switch
51 within the cylindrical member 23b, causing the timer g3, the
driver 98 and the relay 103 to respond in the same fashion as
just described above in conjunction with the first movement of
the patient's forearm. In this case, the pairs of contacts 108,
109 close effecting the energization of the yellow light
producing lamp 43 and the tone generator 118. Here again, the
same sequence of events occur, different and distinctive light
and audible signals are provided to the patient as biofeedback
for a given period of time at the conclusion of which the timer
93 produces a output signal, via the jumper 124, to the timer g4
enabling it and making it ready to receive a start signal. Next
the patient makes a fist (not illustrated), sometimes called a
grasping action, as instructed by ~he therapist closing the
mercury switch 52 which is within the cylindrical member 23c
causing the third channel 79 to operate much in the same fashion
as the foregoing channels providing third audible and visual
feedback signals to be produced by the tvne generator 119 and the
green lamp 44.
Similarly, the patient then releases his fist, receives a
fourth biofeedback stimulation by the energization of the blue
light emitting lamp 45 and the tone generator 120, as a result of
closing mercury switch 53. Thereafter, as the tone and light
- 12 -
12~5~
signals disappear and the subsequent motions are made by the
patient, he releases his fist 50 that his arm, wrist and hand are
in the position as shown in Figure 8A and subsequently performs
supination and pronation movements, achieving the hand positions
as illustrated respectively in Figures 8D and 8E; each of these
motions causes respective tone generators 121, 122 and respective
purple and white lamps 46, 47, via the channels 81, 82, to
respond providing, distinctive visual and audible responses.
Upon the ending of the signals produced as a result of the
energization of the relay 107, part of the last channel 82, which
was energized upon pronation of the patient's wrist, the final
timer 97 produces its reset signal which is coupled, via the
jumper 128 to the set input of the timer 64 and the whole
sequence of events can then again take place. This can be done
over and over again until the patient relearns. During this
time, the intensity of the visual and audible biofeedback signals
can be reduced by manipulation respectively of the variable
resistors 72, 72a, 72b ard the volume control potentiometer 76 by
the therapist as an aid in reducing the dependence of the patient
on the biofeedback signals, making him rely to a higher degree on
his own mental processes.
As illustrated, because each of the timers 64 and 93-97 in
firstly "run down" or unset by momentarily depressing push
buttons 144-148 and the system made ready by depressing push
button 65 to set the system on one channel and the closing of one
mercury switch at any time effects operation, whether any or all
of the other switches are open or closed at any time is not
important because the timers in the other channels will not
start.
Were the patient to unexpectedly move the wrong arm, to
which the six additional mercury switches 131-137 have been
strapped in the fashion intended, a voltage would be produced
across the resistor 130 and coupled via the jumper 138 to the
ir~put of the driver 1~2, causing the relay 1~1 to be energized.
- 13 -
~s~
The energization of the relay 141 close the pairs of contacts
142, 143 causing the red light light source lamp 48 to become
energized and an unpleasant tone to be produced by the tone
generator 144 signaling both to the therapist and the patient
that he has made a wrong movement.
Were the therapist to have fixedly positioned corresponding
mercury switches to his own forèarm, ~7rist and hand, these
mercury switche.s being represented by the switches 56-61, he
could initially instruct a patient by example or intervene in the
biofeedback process to illustrate the movements he wishes the
patient to make.
By way of example, the back of the console shown in Figure 5
may advantageously appear as shown in Figure 7, the jumpers 63,
66, 88~92, 88'-92' and 138, and 123-128, shown schematically in
Figure 6, can be patch cords connecting female jacks as shown in
Figure 7. The patient (P) and therapist (T) input female jacks
; can be seen in the upper left-hand portion of Figure 7 associated
with channels 1-6 (CHl-CH6), the six error input female jacks
being shown in the lower-left portion of Figure 7. Male jacks,
such as jack 26 (Fig. 1) r are insertible in the above-mentioned
female jacks. Respective timers for respective channels CHl-CH6
are diagramatically shown as Tl-T6, the drivers for the
respective orange (O), yellow (Y), green (G), blue (B)~ purple
~P), white (W) and red ~R) lamps being shown as Dl-D7.
This is to be appreciated that the foregoing description and
the accompanying drawings relate to illustrative preferred
embodiment. It is to be appreciated that numerous other
embodiments in variance are possible within the spirit and scope
of the invention, its scope being defined by the appended claims.
