Signal processing system for achilles tendon reflex testing

Claim 2

In a system for testing the Achilles tendon reflex of a patient and operative with an Achilles tendon reflex motion sensor of the type having An optical path between a light source and a light detector with the optical path occluded by the foot of said patient to varying degrees corresponding to the reaction of said foot to induced reflexing of the Achilles tendon, said detector providing an output signal varying with the degree of occlusion produced by said foot, the improvement comprising apparatus for processing the varying detector signal including: means for receiving said varying detector signal; means for detecting first and second points on said varying detector signal and providing an indication of the time interval between said first and second points thereon; said first point representing the commencement of an induced Achilles tendon reflex; said second point being a predetermined decay in the portion of said varying detector signal corresponding to induced Achilles tendon reflex relaxation; means for displaying said received, varying detector signal with an indication of said first and second points thereon.

Claim 3

In a system for testing the Achilles tendon reflex of a patient and operative with an Achilles tendon reflex motion sensor of the type having an optical path between a light source and a light detector with the optical path occluded by the foot of said patient to varying degrees corresponding to the reaction of said foot to induced reflexing of the Achilles tendon, said detector providing an output signal varying with the degree of occlusion produced by said foot, the improvement comprising apparatus for processing the varying detector signal including: means for receiving said detector signal; means for generating a marker signal in response to each change in said detector signal from a signal slope of substantially zero to a signal slope which is significantly non-zero, thereby to produce a sequence of four marker signals with each detected normal Achilles tendon reflex; resettable means for counting said sequence of marker signals, the count thereof providing an indication of the position of each said marker signal in the sequence of marker signals; means responsive to the level of the detector signal both prior to the occurrence of the first marker signal of said sequence and at the occurrence of the fourth marker signal of said sequence for providing a relaxation marker signal when said detector signal reaches a level intermediate said levels before the first and at the fourth marker signal; controllable means for counting at a fixed rate in response to a start signal and for ceasing to count in response to a stop signal; means for producing said start signal upon the occurrence of the first marker signal and for producing said stop signal upon the occurrence of said relaxation marker signal; means for combining said detector signal with said first and said relaxation marker signals to provide a composite signal; means for providing a visual display of said composite signal; and means operator actuable for identifying the count in said counting means as representing desired data for a patient Achilles tendon reflex response.

Claim 4

In a system for testing the Achilles tendon reflex of a patient and operative with an Achilles tendon reflex motion sensor of the type having an optical path between a light source and a light detector with the optical path occluded by the foot of said patient to varying degrees corresponding to the reaction of said foot to induced reflexing of the Achilles tendon, said detector providing an output signal varying with the degree of occlusion produced by said foot, the improvement comprising apparatus for processing the varying detector signal including: means for receiving said detector signal; means for generating a marker signal in response to each change in said detector signal from a signal slope of substantially zero to a signal slope which is significantly non-zero, thereby to produce a sequence of four marker signals with each detected normal Achilles tendon reflex; resettable means for counting said sequence of marker signals, the count thereof providing an indication of the position of each said marker signal in the sequence of marker signals; means responsive to the level of the detector signal both prior to the occurrence of the first marker signal of said sequence and at the occurrence of the fourth marker signal of said sequence for providing a relaxation marker signal when said detector signal reaches a level intermediate said levels before the first and at the fourth marker signal; controllable means for counting at a fixed rate in response to a start signal and for ceasing to count in response to a stop signal; means for producing said start signal upon the occurrence of the first marker signal and for producing said stop signal upon the occurrence of said relaxation marker signal; means for combining said detector signal with said first and said relaxation marker signals to provide a composite signal; means for providing a visual display of said composite signal; and means operator actuable for identifying the count in said counting means as representing desired data for a patient Achilles tendon reflex response.

Claim 5

The apparatus of claim 2 further comprising: a data processor means; and means for conveying the count in said controllable counting means to said data processor means in response to an operator identification thereof.

Claim 6

The apparatus of claim 2 further comprising: means for causing said visual display of said composite signal to commence at substantially the same point along the signal level axis of said display.

Claim 7

Apparatus of claim 2 further comprising a low-pass filter means filtering said detector signal to provide suppression of detector signals resulting from ambient room lighting.

Claim 8

The apparatus of claim 2 further comprising means for inhibiting the generation of a first marker signal for a predetermined interval after the generation of a prior first marker signal, said predetermined interval being significantly longer than thE detector signal produced by all expected Achilles tendon reflexes, thereby to prevent said first marker signal from being generated in response to a foot motion directly subsequent to an Achilles tendon reflex.

Claim 9

The apparatus of claim 2 further comprising: means for producing a predetermined delay in generation of the third marker signal after the corresponding slope change in said detector signal; and means responsive to the running of said predetermined delay for reinitiating the running of said predetermined delay with each occurrence of a detector signal slope change from a zero to non-zero slope during the running of said predetermined delay.

Claim 10

The apparatus of claim 7 wherein said means for generating said marker signals includes means operative to produce one of said marker signals only in response to said slope change being from said zero slope to a non-zero slope of at least a predetermined slope magnitude.

Claim 11

The apparatus of claim 2 wherein said means for producing said relaxation marker signal comprises: means for responding to changes in said detector signal to provide a change responsive signal; a first amplifier means providing a first output signal; controllable means having a first state which prevents passage of said change responsive signal to said first amplifier means and a second state which allows passage of said change responsive signal to said first amplifier means; the first state of said controllable means providing conduction of the input of said first amplifier means to a reference level; a second amplifier means producing a second output signal; means for storing signals which is connected between the output of said first amplifier means and the input of said second amplifier means; said signal storing means having means for providing first and second states, said first state providing storage of the signal between said output of said first amplifier means and said reference level and further providing connection of said input of said second amplifier means to said reference level and said second state providing conduction of said first output to said input of said second amplifier means offset by the signal stored by said storing means; means for producing a signal with a level intermediate the level of said first and second outputs; means for producing said relaxation marker signal in response to said intermediate signal level passing through said reference level with a predetermined slope polarity after said fourth marker signal; said controllable means and said signal storing means being normally in said first states; means for changing the state of said controllable means to said second state in response to the first marker signal; and means for changing the state of said signal storing means to said second state in response to the fourth marker signal; said signal storing means being thereby operative to store a signal representing the difference in detector signal level between the level prior to the first marker signal and the level at the fourth marker signal; said intermediate signal being thereby caused to pass through said reference level at a corresponding intermediate level of said detector signal.

Claim 12

The apparatus of claim 9 wherein said intermediate signal is half-way between the detector signal levels prior to the first marker signal and at the fourth marker signal.

Claim 13

In a system for measuring the Achilles tendon reflex of a patient operative with an electro-optical detector providing a detector signal varying in accordance with the movement of a foot being tested across a light beam, the improvement comprising apparatus for processing the detector signal including: means for amplifying said detector signal; means for low-pass filtering said amplified signal to reduce ambient light interference; means responsive to said filtered signal for providing a two state signal; means for producing transitions between first and second states of said two state signal in response to each change in said filtered signal from a slope of substantially zero to a slope of at least a predetermined magnitude; means for generating a pulse with each transition in said two state signal whereby the detector signal of a normal Achilles tendon reflex causes said pulse generating means to produce a sequence of four pulses; means for indicating which pulse in said sequence of four has occurred most recently; means responsive to said filtered detector signal and operable only after an indication of the fourth pulse in said sequence for providing a marker pulse upon the occurrence of a predetermined relaxation level of said filtered detector signal after said fourth pulse; a circuit means having two states, the first of said two states being produced in response to the first generated pulse in said sequence of four pulses, and the second of said two states being produced in response to said marker pulse; means for counting at a predetermined rate whenever said two state circuit is in said first state; means responsive to said first pulse in said sequence of four pulses and said marker pulse to produce the second state in said two state circuit a predetermined detector signal interval after said marker pulse; means responsive to said second pulse for providing a predetermined delay in the generation of said third pulse; said predetermined delay being reinitiated during its running in response to each transition of said two state signal; means for combining said filtered detector signal with said first pulse and said marker pulse to produce a composite signal; means for producing a visual display of said composite signal; a data processor means; and means for conveying the count in said counting means to said data processor means in response to a command.

Claim 14

In a system for measuring the Achilles tendon reflex of a patient operative with an electro-optical detector providing a detector signal varying in accordance with the movement of a foot being tested across a light beam, the improvement comprising apparatus for processing the detector signal including: means for amplifying said detector signal; means for low-pass filtering said amplified signal to reduce ambient light interference; means responsive to said filtered signal for providing a two state signal; means for producing transitions between first and second states of said two state signal in response to each change in said filtered signal from a slope of substantially zero to a slope of at least a predetermined magnitude; means for generating a pulse with each transition in said two state signal whereby the detector signal of a normal Achilles tendon reflex causes said pulse generating means to produce a sequence of four pulses; means for indicating which pulse in said sequence of four has occurred most recently; means responsive to said filtered detector signal and operable only after an indication of the fourth pulse in said sequence for providing a marker pulse upon the occurrence of a predetermined relaxation level of said filtered detector signal after said fourth pulse; a circuit means having two states, the first of said two states being produced in response to the first generated pulse in said sequence of four pulses, and the second of said two states being produced in response to said marker pulse; means for counting at a predetermined rate whenever said two state circuit is in said first state; means responsive to said first pulse in said sequence of four pulses and said marker pulse to produce the second state in said two state circuit a predetermined detector signal interval after said marker pulse; means responsive to said second pulse for providing a predetermined delay in the generation of said third pulse; said predetermined delay being reinitiated during its running in response to each transition of said two state signal; means for combining said filtered detector signal with said first pulse and said marker pulse to produce a composite signal; means for producing a visual display of said composite signal; a data processor means; and means for conveying the count in said counting means to said data processor means in response to a command.

Claim 17

The system for testing the Achilles tendon reflex of a patient of claim 12 wherein: means are provided for determining the second maximum excursion of said varying detector signal; said means for providing said second signal includes means operative to provide said second signal in response to a predetermined reduction in said varying detector signal beyond the point thereof corresponding to said determined second maximum excursion in said varying detector signal; and said determining means includes means operative to discriminate against excursions of said varying detector signal corresponding to short, spastic foot reactions in determining said second maximum excursion.

Claim 18

The system for testing the Achilles tendon reflex of a patient of claim 12 including means for preventing the providing of said first signal from portions of said, varying detector signal corresponding to foot motions directly subsequent to said tendon relaxation.