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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to myofunctional therapy biofeedback devices,
and more particularly to a biofeedback device adapted to sense the motion
sequence of a tongue during swallowing and speech in coherent relationship
with the tensioning of selected facial muscles.
2. Description of the Prior Art
In the field of myofunctional therapy, efforts generally expended in
aligning the bite are often undone by abnormal swallowing and speech
habits developed prior to the corrective work. In the past, various
techniques have been developed by which the proper alignment of
musculature at any one discrete point during the swallowing cycle is
measured; however, none of those techniques monitor the whole sequence of
significant muscular movements during the swallow. Most prior art devices
of this kind do not provide a ready visual display to the patient by which
the patient himself could notice, without the aid of other persons in
attendance, the immediate propriety of his muscular position. Lacking such
readily obtainable indication, any corrective therapy would necessarily
require the attendance of other persons, thus raising the expense and the
frequency of therapeutic exercises. Furthermore, most prior art devices
only measure a singular position of the tongue and therefore provide no
information to either the patient or the therapist as to the propriety of
the sequence of muscular movements that has occurred. Often the sequence
entails small, and therefore visually hard to perceive, concurrent
muscular contractions such as contractions of the facial muscles which
occur both during a swallow and during speech and which therefore call for
extensive visual inspection by a trained person in order to arrive at a
proper diagnosis.
Accordingly, there is a present need for an appliance which by virtue of
its simplicity could be conveniently bought, leased out by the patient, or
used by a therapist during the therapy periods, such appliance having the
requisite qualities of simplicity of operation and an easily comprehended
display. Since the swallowing sequence often involves muscular
contractions which are essentially on the subconscious level, or the motor
level, the display therefore would be providing biofeedback. In addition,
a device of such kind would necessarily also involve convenient adjustment
features by which the therapist could progressively trim up the training
program until proper speech or swallow habits are obtained. Further, the
same device could be utilized for diagnostic readings by adjusting the
various components thereof to known normals.
SUMMARY OF THE INVENTION
It is therefore the general purpose and object of the present invention to
provide a diagnostic device adapted to monitor the muscular contraction
sequence occurring during swallowing and speech. Further objects of the
invention are to provide, by way of the same diagnostic device, a
convenient display set by the therapist by which selected therapeutic
exercises could be carried out. Yet further objects of the present
invention are to provide a diagnostic device which could be set for
various other abnormal muscular sequences, including abnormal joint
problems, and which could subsequently be gradually corrected to a proper
sequence.
Briefly, these and other objects are accomplished within the present
invention by providing a plurality of electrodes mounted in a fixture
aligning such electrodes behind the front teeth and in selected positions
along the roof of the mouth, to be contacted in sequence by the tongue
both during speech and swallowing. In order to provide an electrical
signal through such electrodes when touched by the tongue, an externally
applied signal source electrode is also provided, attachable to any
surface of the body, the signal source electrode connecting to an
oscillator circuit. The body of the patient is therefore excited by the
oscillator circuit by a selected frequency electrical signal, at signal
levels below any level potentially hazardous to the patient. The tongue,
during passing, therefore completes the circuit across the electrodes
within the mouth and the oscillatory signal is brought out to the exterior
of the mouth on insulated leads. Thus each electrode is brought out by way
of an insulated lead to a corresponding filter amplifier set at a bandpass
centered about the externally imposed oscillation frequency. The outputs
of the respective filter amplifiers are then rectified in corresponding
A.C.-to-D.C. converters, where each converter output is, in turn,
connected to an associated adjustable voltage comparator. The respective
outputs of the comparators are then connected to corresponding indicator
lights to provide a visual display.
In addition to the above-mentioned electrodes, there is a set of externally
applicable sensors mounted on an externally attachable elastic base, the
sensors connecting to operational amplifiers arranged in a differential
mode. The operational amplifiers form bandpass filters passing the
frequency band associated with the biological discharge frequency domain
which occurs in the process of the contraction of a muscle. By way of this
lately referred to set of sensors, a measurement is also taken of any
selected facial muscle which when converted to a D.C. signal is displayed
on a meter and compared to a reference voltage which, when exceeded,
illuminates additional light-emitting diodes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic illustration of the inventive device arranged to
sense and display the tongue and muscular movements of a patient; and
FIG. 2 is a side view, in partial cross section, of a patient's mouth
illustrating a position of the patient's tongue relative the electrodes of
the device shown in FIG. 1.
DESCRIPTION OF THE SPECIFIC EMBODIMENT
While the present invention is described with reference to a swallow,
speech and tempro-mandibular joint diagnostic and therapy device, such
reference is for purposes of clarity only. Although particularly adapted
for such use, other uses are envisioned therefor, and no intent to limit
the scope of the invention is expressed hereby.
As shown in FIG. 1, a holding fixture, generally designated by the numeral
10, is formed in the manner of a bent wire convolved on the interior
surfaces of the teeth of a patient. The general shape of the wire holding
fixture 10 is that of a horseshoe, aligning within the curvature of the
upper jaw. Extending peripherally and radially along the inner surface of
the teeth to the exterior of the central segment of fixture 10 are a
plurality of mounts 11, 12 and 13, mount 12 being disposed substantially
central to the jaw while mounts 11 and 13 being disposed laterally on
either side thereof. Extending in an opposed direction to mount 12, along
the roof of the mouth, is a support member 16 terminating in an end mount
17 and an intermediate mount 18 aligned with the incisive papillae of the
mouth. Mounts 11, 12, 13, 17 and 18 are also formed in the manner of a
bent wire, each retaining on the ends thereof a corresponding electrode,
respectively designated electrodes 31, 32, 33, 37 and 38. Electrodes 31,
32, 33, 37 and 38 connect to corresponding leads 21, 22, 23, 27 and 28. It
is to be understood that the last digit within the designating numerals
for the respective mounts, insulated leads and corresponding electrodes
indicate a collected relationship whereby, for example, mount 11 clasps
the insulated lead 21, lead 21 terminating in the exposed electrode 31.
For the intended use, it is further contemplated that the support member
16 and the fixture 10 both comprise an easily deformable wire structure
adapted to conform to the dimensions of the roof of the mouth and the
teeth surfaces. Furthermore, mounts 11, 12, 13, 17 and 18 similarly
comprise segments of wire of like deformability thus allowing for
manipulation and selective alignment of the electrodes. In this manner,
selective disposition of the electrodes within the mouth of the patient
can be made by the therapist for selective contact with the tongue.
As shown in FIG. 2, the initial proper position of the tongue, designated
T, is against the incisive papillae so that when proper initial tongue
alignment is made, tongue T contacts electrode 38. As the swallow
progresses, electrode 37 is sequentially contacted. Electrodes 31, 32 and
33, on the other hand, provide only an improper indication of initial
tongue portion, and should such occur during any portion of the swallow
sequence, it is intended that the signals from such indicate an improper
reading.
Referring back to FIG. 1, an external signal source electrode 41 is shown
applied to the exterior face surface, electrode 41 terminating in a lead
42 which connects to an oscillator circuit 40.
In addition to the above electrodes, an externally applicable elastomer
sensor fixture, or pad, 60 is illustrated on the side of the patient's
face in FIG. 1. The sensor pad 60 includes sensors 61, 62 and 63 buried
within the interior thereof, sensors 61, 62 and 63 being aligned to
contact the skin of the patient. Accordingly, any galvanic activity
occurring in the underlying muscle is sensed across sensors 61 and 62,
sensor 63 providing the ground reference.
Sensors 61, 62 and 63 are connected by corresponding leads 71, 72 and 73 to
a measurement circuit 70, leads 71 and 72 connecting to the input of a
differentially connected amplifier stage 75 and lead 73 being tied to the
circuit ground. Within stage 75 lead 71 connects to the noninverting
terminal of an operational amplifier 751 which at its negative terminal
includes a unit gain feedback connection to the output. Similarly, lead 72
connects to an operational amplifier 752 on the input side of stage 75,
amplifier 752 again including a unity gain feedback connection. The
outputs of amplifiers 751 and 752 are connected respectively across a
coupling capacitor 753 in series with an input resistor 755 and a
capacitor 754 in series with a resistor 756, to the inverting and
noninverting inputs of an operational amplifier 760.
Operational amplifier 760 includes a negative feedback connection formed by
a resistor 761 and is tied to ground at the noninverting input across a
resistor 762. Amplifiers 751, 752 and 760 thus form a circuit connected in
differential mode, providing both high input impedance relative skin
impedance variations, good rejection of the common mode and a single ended
output.
The output of amplifier 760 connects to a variable gain stage 77. Stage 77
includes an operational amplifier 771 adjustable in gain by way of a
variable feedback resistor 772. Amplifier 771 receives, at the inverting
terminal, the output of amplifier 760 across an input resistor 773. Stage
77 thus provides for convenient gain setting such that physiological
signals at various levels can be sensed.
The output of amplifier 771 is converted to a D.C. signal in an
A.C.-to-D.C. converter circuit 78. More specifically, the output of
amplifier 771 is connected to a resistor 781 connected in parallel across
a series circuit comprising resistors 782, 783 and 784. The other end of
resistor 781 connects to the inverting input of yet another operational
amplifier 785 configured as a low pass filter by way of a feedback
capacitor 786 and feedback resistor 787.
Connected across resistor 783 is a rectifying circuit comprising a diode
788 in series with a diode 789 and a resistor 791. Diode 789 and resistor
791 in turn form an output-to-input return around an operational amplifier
790. Thus, the signal out of amplifier 771 is rectified by the circuit
around amplfier 790 and is then smoothed across amplifier 785. Amplifier
785 then connects both to a meter M, across a resistor 792, and a
compartor circuit 79. Comparator circuit 79 comprises a voltage comparator
formed around an operational amplifier 795 including a positive feedback
resistor 796. The noninverting terminal of amplifier 795 furthermore
connects to the division point of a divider comprising resistors 797 and
789 between a signal source +V and ground, which sets the comparison
voltage. The output of amplifier 795 then connects, across a resistor 799,
to two series connected light-emitting diodes 66 and 68 mounted on a
display board 150. Diodes 66 and 68 complete a circuit between the signal
source +V and the output of comparator 79 and will light up each time
amplifier 795 swings low.
The display board 150 also includes light-emitting diodes 131, 132, 133,
137 and 138 arranged in a geometric correspondence with the arrangement of
electrodes 31, 32, 33, 37 and 38 within the mouth of the patient. Diodes
131, 132, 133, 137 and 138 therefore provide a visual indication of the
contacts made by the tongue T, or of the tongue position, as detected by a
set of corresponding detector circuits 231, 232, 233, 237 and 238.
Since each detector circuit functions, and is therefore constructed, in an
identical manner, only one such circuit, 238, is described in detail
herein, it being understood that circuits 231, 232, 233 and 237 are
identical copies thereof.
Detector circuit 238 connects at the input to lead 28 which communicates to
the interior thereof to form the input to a filter amplifier stage 200.
Within stage 200, lead 28 is connected across an input resistor 201 in
series with a coupling capacitor 202 to the inverting terminal of an
operational amplifier 203. The juncture between resistor 201 and capacitor
202 is both tied to ground across a resistor 204 and to the output of
amplifier 203 across a feedback capacitor 205. In addition to the
capacitive feedback, a feedback resistor 206 is provided between the
inverting input terminal and output of amplifier 203.
Stage 200 therefore is configured as a bandpass filter set to pass the
frequency generated by the oscillator circuit 40 by conventional selection
of the capacitive and resistive components therein. The passed oscillatory
output signal thereof is converted to a D.C. signal by an A.C.-to-D.C.
converter stage 210. Stage 210 includes a series circuit comprising a
diode 211 and a resistor 212, smoothed by a capacitor 213 to ground,
rectifying and connecting the output of amplifier 203 to the input of a
comparator stage 220. Stage 220 is similar in configuration to stage 79
described above, including a divider network comprising an upper resistor
221 and a lower variable resistor 222 tied between the signal source +V
and ground. This divider sets the reference voltage at the noniverting
terminal of an operational amplifier 223 which, similar to amplifier 795,
includes a positive feedback resistor 224 and receives the rectified
signal at the inverting terminal. The output of amplifier 223 then ties
across a resistor 225 to the cathode of the diode 138, on the display
board 150, which at the anode is again tied to the signal source +V.
Diodes 131, 132, 133 and 137 are similarly connected to the corresponding
detector circuits 231, 232, 233 and 237. Thus each time a tongue contact
is made with any of the electrodes, a corresponding displayed diode lights
up. By proper tutoring, the patient is trained to light up only certain
diodes, thus allowing for corrective therapeutic exercises to correct
abnormal conditions.
In order to provide excitation to the detector circuits, the aforementioned
oscillator circuit 40 is connected to the body of the patient. While there
are various ways of providing an oscillating signal, one example of such
is included herein by way of the structure of circuit 40. More
specifically, circuit 40 includes a first operational amplifier 43 tied to
ground at the inverting terminal across a capacitor 44. The noninverting
terminal of amplifier 43 is in turn tied to ground across a resistor 45.
The inverting and non-inverting terminal furthermore connect to the
amplifier output across respective negative and positive feedback
resistors 46 and 47.
The output of amplifier 43 then connects across an input resistor 48 to the
inverting terminal of yet another amplifier 49 which includes a variable
resistor 51 forming a negative feedback thereacross. The output of
amplifier 49 then connects to the lead 42 which at the other end
superposes an oscillatory, low current, low voltage signal to the
patient's body.
The method of correlating the above-described apparatus is now set forth
with particular reference to FIG. 2. As shown in FIG. 2, the measurement
of facial muscles can be controlled by way of a conventional 2.5 cm
calibration instrument 55 which is provided with a load measuring
indicator 56. One end of the instrument 55 is retained by the patient's
embouchure and the withdrawal force is thus measured concurrently with the
reading of meter M. The gain of stage 77 is then adjusted at the
supplier's facility to light up diodes 66 and 68 upon achievement of
proper muscular tension levels. Once set, the meter M can be used to
measure the muscular levels of any patient. Diodes 131, 132, 133, 137 and
138 provide the tongue position indication. Upon reaching a proper
lighting combination of the diodes, the patient can then proceed with
repetitive exercises until proper habits are achieved.
The many advantages of the present invention should now be readily
apparent. The invention provides a convenient device by which various
tongue positions can be monitored and which renders unattended
thereapeutic exercises feasible. Such features are carried out by
apparatus which is simple to produce, requires few adjustments and is
conveniently adaptable to various patients.
Obviously, many modifications and variations of the present invention may
be made with regard to the foregoing detailed description without
departing from the spirit of the invention.
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