System and method for detecting facial symmetry
First Claim
1. A facial impedance measurement system, for obtaining impedance measurements reflective of the condition of a patient'"'"'s face, comprising:
- electric field means for generating an electric field oriented along a facial mid-line on said patient'"'"'s face; and
impedance means operative concurrently with said electric field means for determining an impedance value related to at least one location on said patient'"'"'s face, said at least one location being displaced from said facial mid-line to obtain a measure of the patient'"'"'s facial condition.
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Abstract
There is provided a system and method for detecting facial symmetry of patients with hemiparesis, or unilateral facial palsy, by facial impedance measurement which quantifies lack of facial symmetry and thereby provides a program for therapeutic stimulus of paralyzed facial muscles. A mid-line of facial current is generated between an upper electrode above the eyes and a lower electrode on the chin, the facial current being sub-threshold so as to avoid any muscle stimulus. Impedance measurements are taken by determining the voltage between symmetrically placed facial electrodes, or between electrode pairs consisting of one electrode positioned around the eye, cheek or mouth, and a reference electrode placed on the patient'"'"'s chin so as to provide an effective bottom point of the Wheatstone bridge formed by the face. The voltage measurements translate into impedance measurements which are indicative of muscle paralysis, and provide a simple but reliable method of obtaining objective data useful for facial movement assessment. Objective current can be either sinusoidal or a train of pulses. In one specific embodiment, the measurement subsystem comprises a sigma-delta loop which includes the patient'"'"'s face as a signal domain; the phase of the injected current is modulated in a manner similar to the negative feedback branch of a standard sigma-delta loop circuit, thereby providing a digital output which is relatively free of signal artifacts.
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Citations
26 Claims
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1. A facial impedance measurement system, for obtaining impedance measurements reflective of the condition of a patient'"'"'s face, comprising:
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electric field means for generating an electric field oriented along a facial mid-line on said patient'"'"'s face; and impedance means operative concurrently with said electric field means for determining an impedance value related to at least one location on said patient'"'"'s face, said at least one location being displaced from said facial mid-line to obtain a measure of the patient'"'"'s facial condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A facial impedance measurement system, comprising
a first pair of electrodes positioned substantially mid-line on a patient'"'"'s face; -
electric field means connected to said first pair of electrodes for generating an electric field pattern on said patient'"'"'s face; a second pair of electrodes positioned on said patient'"'"'s face, at least one of said electrodes being positioned at a prescribed facial location off of the patient'"'"'s facial mid-line; and impedance detection means connected to said second pair of electrodes for obtaining a voltage measurement across said second pair of electrodes which is indicative of patient facial impedance relating to said prescribed location. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A method of facial impedance measurement, comprising:
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positioning a pair of injection electrodes substantially mid-line on the patient'"'"'s face, and connecting an electrical generator thereto to generate a transcutaneous electric field between said pair of injection electrodes; positioning a pair of sensing electrodes on the patient'"'"'s face, at least one of said sensing electrodes being positioned laterally away from said mid-line; and obtaining impedance data from said sensing electrodes, said impedance data being reflective of the patient'"'"'s facial symmetry. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A method of facial impedance measurement, comprising:
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establishing and carrying out a protocol of patient facial movements, each movement relating to a facial position; injecting a transcutaneous current substantially mid-line along a patient'"'"'s face, thereby establishing an electric field relative to said mid-line; and following each of said facial movements, obtaining a measure of the facial impedance between the related facial position and a reference position.
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Specification