WO2005122894A1 - Method and electronic computing device for suppressing and evaluating tremors and spastic movements in relation to input and control peripherals - Google Patents

Abstract

The invention relates to an electronic computing device which, when applied to a digital or analogue signal from an input peripheral (computer mouse, wheelchair control system, etc.), can be used to distinguish a voluntary movement from shaking caused by neurological disorders suffered by the user. The inventive device adapts automatically to the specific characteristics of the user's tremor, regardless of whether it is a resting tremor (characteristic of Parkinson's disease), a postural tremor (characteristic of an essential tremor) or a kinetic/intention tremor. As a result, the device does not have to be specifically adapted to the characteristics of the user. The output signal from the device corresponds to a pathological-tremor-free command.

Description

Title

METHOD AND ELECTRONIC AND COMPUTER DEVICE FOR THE SUPPRESSION AND VALUATION OF TEMPERATURE AND SPASTIC MOVEMENT IN INPUT AND CONTROL PERIPHERALS

Technical sector

The present invention relates to applicable electronic devices as technical aids for disability and for the assessment and diagnosis of neurological disorders. As such, they are mainly applied in the electronic and computer industry of rehabilitation and biomedical.

State of the art

Movement disorders are common in diseases with neurological origin. Among the most disabling disorders can be mentioned tremor and spastic movements. Both movement disorders may have different characteristics depending on the origin of the movement or the patient's condition. Among the types of tremor commonly related to the upper limbs are quiescent tremor (typical of Parkinson's disease), postural tremor (characteristic of essential tremor), and kinetic or intentional tremor.

The tremor of neurological origin is a rhythmic movement characterized mainly by a fundamental harmonic component, although in some cases (physiological tremor) two main components are described. The frequency of rhythmic oscillations vary depending on the type of tremor and are generally considered to be bounded in the range from 2 Hz to 12 Hz. Spastic movements are characterized by sudden movements as spasms of varying amplitude and may affect to various parts of the body. Both movement disorders have an undesirable effect on the command function that people affected by these diseases perform with input peripherals: computer mice, wheelchair controls, etc. Or other command and control devices (push buttons, joysticks ...) The effect of tremor or spastic movement has been attempted to mitigate by specific devices for specific functions. This is the case of the commercial device known as "Neater Eater", which through the application of dissipating damping loads allows to perform the feeding function in an acceptable way.

US patent US6561993 describes a system and method for canceling the effect of essential tremor in computer peripherals. The system comprises a computer program that allows to characterize the tremor of the user. With the characterization a user profile is created that can be used on the computer itself or exported to another computer. With this profile a filtering of the tremor of the user is carried out centered on its fundamental frequency according to the characterization.

The system thus described is specific for a type of tremor (essential), it does not allow to contemplate the possible fluctuations in the characteristics of the tremor of the user depending on his condition (medication, muscular fatigue), its use is confined to peripherals of entry into computers and it requires the calibration and export of profiles in the computer so another user must repeat the process.

The patent application of invention 200301767 proposes a method of biomechanical cancellation of tremor. The invention contemplates an orthotic device that incorporates a variety of measuring elements for the determination of patient movement, a series of algorithms for identifying the pathological tremor component and active elements that allow the application of cancellation actions by repetitive control loops. .

Other patents, such as US5293879 or US 5964720, focus on procedures for the detection of tremor as a result of neurological diseases and procedures for generic physiological monitoring and in particular for tremor monitoring, including biomechanical, cardiac or respiratory monitoring devices and procedures for the differentiation of body movement. Description of the invention

- Brief description of the invention

Neurological diseases commonly lead to movement disorders. Among the most common are tremor and spastic movement. Although the tremor is due to a rhythmic and harmonic oscillatory pattern, the characteristics of this movement (amplitude and frequency) vary according to the etiology and condition of the patient.

Depending on the neurological origin, the tremor is resting, affecting the upper limbs when the muscular system is at rest, postural in the event that the muscular system is maintaining a determined or intentional or kinetic posture in the case of voluntary movement. . These different types of tremor have rhythmic oscillation frequencies of the upper limb in the range between 2 Hz and 12 Hz. In some specific types of tremor (physiological) the presence of a second fundamental component is observed, possibly of higher frequency.

When the patient's condition varies due to medication, muscle fatigue, fatigue or any other reason, both the frequency of oscillation and its amplitude can be affected.

This proposal presents an electronic or computer device that applied to the electrical signal generated by the input and / or command peripherals, whether digital or analog (computer mice, wheelchair controls or any other utensil that requires it ), allows to discern the part of the action of command that corresponds to the voluntary movement and as a consequence eliminate the involuntary movement with origin in neurological disorders be this tremor or spastic movement.

In the process of separation of voluntary and involuntary movement an estimate of the movement disorder (tremor, spastic movement ...) is obtained, so that the present proposal allows the functional assessment of the severity of the movement disorder and its evolution. The present invention comprises the following component elements or steps: 1. An electronic device that allows the acquisition of the command signal, whether analog or digital, from an input peripheral specific to computers (computer mouse, digitizing table) as of a generic nature for the command of any device (, push buttons, levers, wheelchair controls or other devices). The electronic device is useful only in the solution and electronic method described herein and integrates programmable elements (controllers, processors ...) on which it is possible to program the identification, monitoring and evaluation loops of the next point. Additionally, the electronic device incorporates the necessary elements for the reproduction of the command signal, this time the involuntary component of the movement has already been eliminated, and for the storage and wired or wireless transmission of the results of the evaluation of the severity of the disorder. 2. The second stage includes an identification and tracking loop of the voluntary movement that may or may not use movement disorder models. This stage also includes the implementation of functions to assess the severity of the movement disorder based on the estimation of tremor or spastic movement offered by the identification and monitoring loop. to. The adaptive identification, monitoring and evaluation loop can be implemented on the controller described in the previous point, in which case the device takes the form of an electronic adapter whose effect is to select the voluntary component of the command signal that arrives from the peripheral input and offer a command signal free of involuntary movement, and therefore applicable to any command device incorporating the function of assessing the severity of the tremor. b. The adaptive identification, monitoring and evaluation loop can be implemented as a computer program of the device to be commanded (a computer), in which case it can act directly on the input peripheral signal without the need for prior signal conditioning steps. The result is equivalent, obtaining as a result a command (computer mouse movement) free of involuntary movements and incorporating the function of assessing the severity of the tremor. In the state of the art there is a description of a similar device (US6561993) in regard to the function of eliminating involuntary movement, which differs from the present proposal in that it focuses solely on the computing solution, in which it contemplates only disorders of the tremor type movement and among them only the essential postural tremor, in which the procedure of elimination of the tremor is not adaptable and therefore requires a prior calibration process and the archiving of a user profile and as a consequence does not contemplate the variations during the operation of this type of involuntary movements depending on the condition of the user and in that it does not incorporate functions of assessment and evolution of the severity of the movement disorder.

This proposal is of a general nature. Given the adaptability of the tracking loop it is useful for different kinds of tremor and spastic movements. It is also adaptable to the user's condition and does not require a prior calibration process, the generation of user profiles or the export of them. It is also of use in the command of other devices that due to their intrinsic characteristics do not incorporate a processor on which to implement the monitoring loops thanks to the use of the proposed electronic solution. Additionally, it provides a method and procedure for the functional assessment of the severity of the movement disorder and its evolution. - Detailed description of the invention

The pathological tremor of neurological origin presents a rhythmic and harmonic oscillation of the different segments of the upper limb of the patients affected by these diseases. This oscillation is characterized by frequencies in the range of 2 to 4 Hz for the case of resting tremor characteristic of Parkinson's disease. Postural tremor is, however, characterized by a frequency range between 5 and 8 Hz and is characteristic of essential tremor disease. On the other hand, kinetic tremor can occur at frequencies between 4 and 12 Hz and is characteristic of patients with traumatic brain damage.

Some other specific types of tremor such as increased physiological tremor may present oscillations in two frequency bands. The fundamental low frequency component is located in the range between 2 to 5 Hz and the higher frequency component is specific to each segment of the upper limb. In all cases, the characteristics of the tremor (amplitude and frequency) can be altered depending on the patient's condition (medication, fatigue or muscle fatigue, alcohol intake ...)

Neurological disorders may also be accompanied by spastic movement disorders. These disorders are involuntary abrupt movements of varying amplitude and intensity and as in the case of tremor they are largely disabling.

Generally voluntary movement is characterized by frequencies significantly lower than those of tremor. In addition, the latter is an essentially harmonic (rhythmic) movement. Taking advantage of these two characteristics it is possible to determine strategies that allow differentiating both types of movement. Specifically, a possible strategy is the filtering of the motion signal with low or high pass filters designed with cut-off frequencies in the frequency range between voluntary and trembling movement. The filters so designed can be implemented both digitally and analogically and in mixed mode and can be any order, that is, pending rejection at the higher or lower prohibited frequencies.

Se puede utilizar este error para plantear un proceso de seguimiento por optimización por mínimos cuadrados o cualquier otro procedimiento de los parámetros del modelo de la ecuación (1 ).Taking advantage of the essentially harmonic characteristic of the tremor, another procedure for the identification and monitoring of the voluntary and involuntary component (tremor or spasm) can be based on (although it should not be restricted to) its modeling by means of a series development of a set n of main harmonics of frequency f¡ and the corresponding set of secondary M, as reflected in equation (1). n M Σ Σ ^ ^{• YES1 V} fi ^k + ^W r ^{+ M} ki ^{• C0S} * ₍₁ ) »= 1 r = \ The error, βk, can be established between the model of equation (1) and the signal actually obtained through a variety of sensors or any device that picks up the movement of the upper limb, as is the case with the command peripherals at time k, Sk, according to equation (2). ^β _* = ^ff * "* ^{• if} rf _t k + w _r + M _u ^• eos rf _t k] ₍₂₎

This error can be used to propose a follow-up process for optimization by least squares or any other procedure of the model parameters of equation (1).

As a result of this type of algorithm, we obtain: a) The real-time estimation of the voluntary component (ie free of tremor or spastic movement) of the movement, b) The real-time estimate of the movement disorder (ie tremor or static movement), c) An estimate of the measure of the severity of the movement disorder based on the estimation of the previous point b). Computer control peripherals or any other device, device or mechanism (wheelchairs ...) collect the user's movement (be it from the upper, lower limb or any other part of the body) and they convert into electrical, analog or digital command signals (for the positioning of the cursor on computers or for the general operation of the device being commanded). The digital or analog command signal can also be modulated according to a multiplicity of procedures. The electrical command signal generated by these devices is affected by involuntary movements (spastic or tremor) and may lead to a practical impossibility of handling them.

The proposed invention aims to solve the problem of the unwanted effect of movement disorders on the command of any device in general. Simultaneously, a method of functional assessment of the severity of the movement disorder and its evolution is proposed. To this end, a two-stage solution is proposed. The first stage is only necessary in the case where the commanded device does not have processors on which to implement the identification and monitoring loop of the voluntary movement of command and assessment of the severity of the neurological disorder. 1. The first stage aims to enable the application of voluntary movement monitoring links in any electronic command device as well as the assessment of the severity of the movement disorder and its evolution. In anticipation that the commanded device does not include some type of processor on which to implement the monitoring loop, this first stage will be fundamentally electronic and will include: a. Electronic components for the acquisition of command signals affected by movement disorders, whether analog or digital. These signals will be received generally from any specific or general purpose peripheral device for artifact command. b. Electronic components for preprocessing, modulation if necessary and signal adaptation for the subsequent stage of implementation of the monitoring loop. c. Programmable electronic components on which it is possible to implement the ties of identification and monitoring of voluntary movement and assessment of the severity of the neurological disorder. d. Electronic components for the storage and wired or wireless transmission of the valuation results based on the tracking and valuation identification algorithms. and. Electronic components for post-processing and formatted modulation or coding, if any, for the restoration of the command signal already cleared of the effects of the movement disorder according to the specific characteristics of the device to be commanded.

2. This second stage constitutes the implementation of an identification and monitoring loop of the user's voluntary command movement (example of which is the tracking and identification algorithm described above) and therefore the effective elimination of tremor or spastic movement. This stage includes the implementation of the function of functional assessment of the severity of the movement disorder. Depending on the characteristics of the commanded artifact, this stage will take place: a. When the commanded device does not have programmable elements on which to implement a monitoring loop such as the one presented above as an example, its implementation is developed on the electronic element described in point 1. b. When the commanded device has programmable elements on which to implement follow-up ties (for example, computers, personal assistants ...), alternatively and without prejudice to solution 2a, the Implementation of follow-up ties can be performed on such programmable elements.

Example of embodiment of the invention

Without loss of generality, in this section the case of the realization of the invention is presented in the obtaining of a signal free of tremor effects or spastic movements in a driving command of an electric chair.

Since the electric chair will not, in general, have on-board programmable devices for its control, the tremor and spastic movement suppression device and functional assessment of the severity of the disorder constituted by stages 1 and 2nd.

It is also assumed without loss of generality that the chair's command device generates analog signals for its control. Component 1 will consist of: a. A microcontroller or processor with at least two analog acquisition channels (or more if necessary) corresponding to the command of the two main directions of chair driving, that is, forward and turn. The conversion of the analog signal to digital in these channels will be carried out with the appropriate resolution to obtain a faithful digital representation of the source analog signal, typically the resolution may be greater than 8 bits. At a stage prior to the acquisition of the command signal, it is possible to implement elements of pre-processing and adaptation of the signal, typically filters to limit the band of the command signal (in general filters pass low cut-off frequency in the environment 20-30 Hz will be sufficient to fully retain the information of the voluntary and trembling movement) and amplifiers for the adjustment of the signal range to that of the acquisition channels. b. The microcontroller or processor will have the appropriate characteristics for the implementation of some tracking algorithm and identification of the voluntary component of the command signals acquired. Specifically, it will have an adequate cycle time, typically a few hundred Hz will be sufficient given the frequency range of the signals involved. For this purpose, the crystal will be selected in a way that is compatible with the microcontroller and this frequency range. Additionally, the microcontroller will have sufficient program and data memory for program storage to describe an implementation in the time domain of the voluntary tracking and identification algorithm. As an example of a tracking algorithm, the one described above can be used. To do this, based on the error of following the equation (2), an iterative method of convergence of the model described by equation (1) can be developed by optimization by least squares. Such a process results in computationally inexpensive and precise algorithms. c. The microcontroller will have analog and / or digital output channels on which the estimate of the voluntary movement offered by the identification and monitoring loop of the previous point will be written. These output channels, after adequacy of the corresponding electrical levels, will be electrically connected to the points where the peripheral input device would originally be, without further modification of the system.

Detailed explanation of the drawings

Figure 1

The figure shows the functional diagram of the electronic device and schematizes the method of suppressing tremor and spastic movements in input peripherals to govern devices that do not have processors on which to implement the identification and monitoring loop of the voluntary command. Block 1 represents a set of electronic components whose function is to capture the command signal generated by a specific or general purpose input peripheral. Block 2 represents the set of electronic components that allow the signal to be adapted captured for the later stage of implementation of the identification loop. Block 3 represents the programmable electronic element on which the function of the identification and monitoring loop of the voluntary command has been implemented and therefore performs the effective elimination of tremor or spasm, as well as the function of assessing the intensity of movement disorder . Block 4 represents the set of electronic elements or components that allow to restore the command signal, once the involuntary movement has been eliminated, in accordance with the requirements of the device to be commanded.

Figure 2 The figure schematically represents the development alternative by means of the computerized method of suppressing tremor and / or spastic movement in the event that the commanded device has programmable components on which to implement the identification and monitoring loop of the voluntary command movement . In this case a single block represents the implementation of the tracking algorithm on the programmable element of the commanded device and is equivalent to block 3 of the previous figure. This block implements a generic algorithm for identification and monitoring of voluntary movement. Specifically and by way of example, the algorithm described above can be implemented based on the multi-frequency sinusoidal model, the adjustment of this model by least squares or any other procedure and the estimation as a result of the voluntary command movement, which results in a smooth movement of the cursor, without the effect of trembling or spastic movement. This algorithm also generates an assessment of the severity of the tremor based on the estimation of the involuntary component of the movement.

Figure 3

The figure shows the process of identification and monitoring of the voluntary movement of command, from any input peripheral, and in order to command any artifact, as well as the process of generating the assessment of the severity of the movement disorder from of the estimation of the involuntary component thereof. In block 1 a model of the spastic movement and / or tremor is established, which following the example of algorithm described in this proposal can be sinusoidal. In block 2, this model is formulated recursively so that its implementation from the command signal of the input peripheral can be easily implemented in real time.

Block 4 represents the acquisition of the command signal (including involuntary movements) from an input peripheral. With the signal provided by block 4 and the recursive approximation of block 2, some measure of the error between the real signal and the model is estimated. Block 5 implements an optimization of the model parameters based on the minimization of the error measurement of block 4. Finally, the estimate obtained for voluntary movement, block 6, (therefore free of the effects of movement disorders), It is used for the command of all types of artifacts. Additionally, block 7 can implement strategy 1d and obtain an estimate of the movement disorder, from which an evaluation of it can be obtained.

Claims

Claims 1. Method of reduction, cancellation or elimination of the unwanted effect of movement disorders of neurological origin, that is, resting tremor, postural, kinetic, intentional, physiological, increased physiological or any other type, and / or spastic movements , on the action of any specific input peripheral (computer mice, digitizing tables ...) or general control (wheelchair controls, joysticks, levers, keyboards, pushbuttons, pointers ...) to the command of all types of artifacts or data entry, comprising: a. Strategy for identification and monitoring of voluntary movement (free of the involuntary component due to movement disorder), adaptable continuously and automatically to possible alterations, effect of changes of any kind on the user's condition (fatigue, muscle fatigue, intake of alcohol ...) or the change of user of the device, in real time from the electrical input signal of controls or peripherals of a general or specific nature, b. Identification strategy for monitoring and characterization of pathological tremor if it were present in the electrical input signal of controls or peripherals of a general or specific nature, adaptable continuously and automatically to possible alterations thereof, the effect of changes of any kind on the condition of the user (fatigue, muscle fatigue, alcohol intake ...) or the change of user of the device, c. Identification strategy monitoring and characterization of spastic movement if it were present in the electrical input signal of controls or peripherals of a general or specific nature, adaptable continuously and automatically to possible alterations thereof, effect of changes of any kind on the user condition (fatigue, muscle fatigue, alcohol intake ...) or the change of user of the device, d. Strategies for functional assessment of the severity of the movement disorder and its evolution, based on the strategies of points 1 and 1c. 2. Electronic device consisting of: a. Electronic stage for the acquisition of command signals, analog or digital of any kind, received generally from any control or input device, b. Electronic stage of pre-processing, de-modulation and adaptation of the signal acquired in 2a, for its treatment in 2c, c. Electronic stage with programmable components (processors, controllers ...) on which the method described in 1, d. Electronic stage for storage and transmission where it comes from the results of strategy 1d, e. Electronic stage for post-processing, modulation, coding and / or formatting for the restoration of the command signal free of unwanted effects after the implementation of method 1. 3. Strategy to eliminate movement disorders based on the method described in claim 1, specifically in strategies 1a, 1b and 1c, which is carried out by means of an algorithm in the time or frequency domain and which is implemented in real time in the electronic device of claim 2. 4. Strategy to eliminate movement disorders based on the method described in claim 1, specifically in strategies 1a, 1b and 1c, which is carried out by means of an algorithm in the time or frequency domain and which is implemented in a computer program of the device to be commanded, in which case it can act directly on the peripheral signal or input command without previous signal conditioning stages. 5. Strategy for assessing the severity of movement disorders and their evolution based on the method described in claim 1d, which is carried out by means of an algorithm in the domain of time or frequency and which is implemented in real time in the electronic device of claim 2. 6. Strategy for assessing the severity of movement disorders and their evolution based on the method described in claim 1d, which is carried out by means of an algorithm in the domain of time or frequency and which is implemented in a computer program of the device to be commanded, in which case it can act directly on the signal of the peripheral or input control without previous stages of signal conditioning. 7. Elimination process of movement disorders based on the method described in claim 1, specifically in strategies 1a, 1 and 1c, which is performed in real time, generating a command free of the effect of tremor or spastic movement in a manner instantaneous or with a delay that does not affect the response speed of the control or peripheral input used by the user and that allows its application to any variety of pathological tremor or spastic movement, adaptable continuously and automatically to any user condition or different users 8. Process for assessing the severity of movement disorders and their evolution based on the method described in claim 1d, which is carried out in real time, generating an assessment of the effect of tremor or spastic movement instantaneously or with a delay that does not affect the response speed of the control or peripheral input used by the user and that allows its application to any variety of pathological tremor or spastic movement, adaptable continuously and automatically to any user condition or different users and that can be stored or transmitted for analysis.