The manifestations of essential tremor usually worsen with age. In addition, there is some evidence that people with essential tremor are more likely than average to develop other neurodegenerative diseases such as Parkinson''s or Alzheimer''s diseases, especially if the tremor first appears after 65 years old [4, 5, 6, 7]. With the above, this work is carried out in frequency analysis of electromyography signals acquired through a MYO in patients who emulate tremor to identify the tremor of the voluntary components of a recorded signal.
International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 12, December 2019, pp 303-310, Article ID: IJMET_10_12_033 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=12 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication FREQUENCY ANALYSIS OF BIOPHYSIOLOGICAL SIGNS OF PEOPLE WITH TREMOR Angie J Valencia C Faculty of Engineering Militar Nueva Granada University, Bogotá D.C., Colombia Mauricio Mauledoux Faculty of Engineering Militar Nueva Granada University, Bogotá D.C., Colombia Edilberto Mejia-Ruda Faculty of Engineering Militar Nueva Granada University, Bogotá D.C., Colombia Ruben D Hernández Faculty of Engineering Militar Nueva Granada University, Bogotá D.C., Colombia Oscar F Avilés Faculty of Engineering Militar Nueva Granada University, Bogotá D.C., Colombia ABSTRACT Tremor is defined as an oscillatory, rhythmic and involuntary movement of one or more parts of the body People who suffer from this type of disorder usually have difficulty performing daily tasks, such as: working, bathing, dressing and eating; which significantly decreases the quality of life, being shameful and even disabling [1, 2, 3] The manifestations of essential tremor usually worsen with age In addition, there is some evidence that people with essential tremor are more likely than average to develop other neurodegenerative diseases such as Parkinson's or Alzheimer's diseases, especially if the tremor first appears after 65 years old [4, 5, 6, 7] With the above, this work is carried out in frequency analysis of electromyography signals acquired through a MYO in patients who emulate tremor to identify the tremor of the voluntary components of a recorded signal Keywords: Quality of Life, Neurodegenerative Diseases, MYO, Oscillating Movements, Tremor, Fourier Transform http://www.iaeme.com/IJMET/index.asp 303 editor@iaeme.com Angie J Valencia C, Mauricio Mauledoux, Edilberto Mejia-Ruda, Ruben D Hernández, Oscar F Avilés Cite this Article: Angie J Valencia C, Mauricio Mauledoux, Edilberto Mejia-Ruda, Ruben D Hernández, Oscar F Avilés, Frequency Analysis of Biophysiological Signs of People with Tremor International Journal of Mechanical Engineering and Technology 10(12), 2019, pp 303-310 http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=12 INTRODUCTION Tremor is defined by a series of muscular contractions that produce agitated movements in different parts of the body, most often affecting the hands, followed by the arms, head, vocal cords, torso and legs This can be constant or intermittent, sporadic or the result of another usually neurological disorder The frequency of the tremor is the "speed" of the shake and may decrease as the person ages, while the intensity of the tremor increases [8] This muscular disorder is usually caused by a problem in the deep parts of the brain that are responsible for muscle movement Other causes include the use of certain medications, alcoholism or alcohol withdrawal after a period of excessive consumption, mercury poisoning, overactive thyroid, liver or kidney failure, and anxiety or panic [9] The tremor is considered not to be life-threatening, but it can be embarrassing and disabling, which makes it difficult or impossible to work or perform tasks in everyday life [3, 10] Muscle disorders can be classified according to their appearance, their cause or origin, so there are about 20 types of tremor Among the most common include: Essential tremor, which is one of the most common disorders, being mild and remaining stable for many years The tremor usually appears on both sides of the body, but often becomes stronger in the dominant hand because it is an action tremor [11, 12] Additionally, there is dystonic tremor, which occurs in people affected by movement disorders where incorrect brain messages cause muscle hyperactivity, which result in abnormal postures due to strong muscle spasms or cramps, reducing their intensity by touching the part of the affected body or muscle [11] There is also the so-called cerebellar tremor, which is defined as being a slow and wide tremor of the extremities, which occurs at the end of an intentional movement, such as trying to press a button As the name implies, it is caused by an injury to the cerebellum and the pathways from this to other brain regions [11] There is also the physiological tremor that occurs in all healthy people, which is not considered a disease, but a normal human phenomenon that results from the physical properties of the body [12] And finally, there is parkinsonian tremor and orthostatic tremor The first presents itself as a common symptom of Parkinson's disease, and manifests itself by shaking one or both hands when they are at rest While orthostatic tremor is a rare disorder that is characterized by rapid muscle contractions in the legs when standing It is usually accompanied by a feeling of instability or imbalance, which makes people immediately try to sit or walk [12, 13] For the proper management of the techniques that must be implemented in the development of devices that contribute to the rehabilitation of patients with pathological tremor, the tremor and voluntary components of a registered signal must be distinguished in the first instance, either for diagnosis or treatment , with which strategies have been used ranging from linear filtering to stochastic estimators In [14] an optimal digital filter was designed offline through follow-up tasks In [15] they used a second-order low pass filter applied to an electromyography tremor signal to be transmitted to a neural network, intended to control an elbow device In [16] they used a high-pass filter to separate the tremor component before passing it to a repetitive control loop using a functional electrical stimulation system Another recent work used a tremor estimator in the form of a high-pass filter, which resulted in a significant phase change, which was corrected before being applied to the suppressor actuator [17] http://www.iaeme.com/IJMET/index.asp 304 editor@iaeme.com Frequency Analysis of Biophysiological Signs of People with Tremor Another estimation method is the linear weighted Fourier combiner that adaptively shakes a tremor signal by tracking its frequency, amplitude and phase [18, 19] However, to obtain the best performance, it is recommended to perform a pre-filtering stage with a high pass filter [20, 21] A different approach was presented with an adaptive bandpass filter, proposed by [22] and compared favorably with the weighted frequency Fourier linear combiner The Kalman filter is a stochastic estimator, based on a Bayesian model that has been used for the suppression of tremor by several researchers In [23] and [24] they implemented a Kalman filter to track the voluntary movement and by subtracting it from the total movement, obtain an estimate of the tremor, used to control an upper arm orthosis of three degrees of freedom Additionally, GH and Benedict-Bordner filters were used, differentiated by the method of weight selection [25] In [26] they have also implemented the Kalman filter, merging the information from the accelerometer and electromyography data, to obtain a single estimate of the tremor angle that will be used in the diagnosis, classification and applications of functional electrical stimulation The present work is structured as follows: Section 1, describes the stage of calibration of the system with basic movements performed by the user In section 2, the frequency analysis of results and simulations will be performed Finally, in section conclude on the data obtained by applying Fourier transform ACQUISITION OF ELECTROMIOGRAPHIC SIGNS 2.1 System Calibration For the analysis of electromyography data in patients with tremor, the development of an interface that provides the possibility to acquire and save in tables the values obtained during the execution of the tests is carried out From there it begins with initial calibration stages from which the values in orientation, rotation and acceleration are obtained for a forearm flexion movement, an extension movement, lateral forearm rotation, average forearm rotation, supination movement and pronation movement 2.2 Frequency Spectrum of People with Tremor Biophysiological signals are acquired through MYO, from people with and without tremor for movement patterns given by drinking a drink Having as constants an empty glass that allows to have the same weight in all the samples obtained After the collection of information, an analysis is carried out in the frequency spectrum through the Fourier Transform (FT) This in order to observe the behaviors in module and phase that are characteristic of people with tremor RESULTS AND DISCUSSION Of the data that should be considered are those acquired by the gyroscope and accelerometer at the coordinates X, Y, Z In Figure and 2, the phase behavior of a healthy and sick person is observed for an accelerometer movement in the coordinate Z respectively http://www.iaeme.com/IJMET/index.asp 305 editor@iaeme.com Angie J Valencia C, Mauricio Mauledoux, Edilberto Mejia-Ruda, Ruben D Hernández, Oscar F Avilés Figure Z accelerometer phase – Sick Figure Z accelerometer phase – Healthy From there, differences are observed in the phase distribution of a sick and healthy person For example, in Figure 2, the largest number of samples are concentrated in the range of -0.3 to 0.3, which if analyzed in the real (abscissa) and imaginary (ordered) planes, mean behaviors without oscillations In the phase diagram, the dispersion in the histogram samples is directly related to the oscillations of the signal, so the behavior in Figure corresponds to an increase in the oscillations generated by involuntary muscle movements with respect to the signs of a healthy person (Figure 2) On the other hand, the modulus behavior (real part of the FT) of the Z accelerometer signal is observed and compared for sick (Figure 3) and healthy person (Figure 4) http://www.iaeme.com/IJMET/index.asp 306 editor@iaeme.com Frequency Analysis of Biophysiological Signs of People with Tremor Figure Z accelerometer module – Sick Figure Z accelerometer module – Healthy From there, symmetric distributions are observed in both signals that are reflected in similar response times, which means that both movements took approximately seconds to execute So, the phase behaviors for the X and Y coordinates will be analyzed, which are those in which the vibrations have their greatest effect Starting with the signals in X coordinates, shown in Figures and 6, and for Y coordinates in Figures and Figure Accelerometer phase in X – Sick http://www.iaeme.com/IJMET/index.asp 307 editor@iaeme.com Angie J Valencia C, Mauricio Mauledoux, Edilberto Mejia-Ruda, Ruben D Hernández, Oscar F Avilés Figure Accelerometer phase in X - Healthy Figure Accelerometer phase in Y - Sick Figure Accelerometer phase in Y - Healthy Similar behaviors are observed to those obtained in Z, which verify the existence of vibrations (tremor) by the distribution in the phase histogram of the MYO accelerometer signal http://www.iaeme.com/IJMET/index.asp 308 editor@iaeme.com Frequency Analysis of Biophysiological Signs of People with Tremor CONCLUSIONS With the analysis of the discrete Fourier transform, the frequency spectra in magnitude and phase of the signals of people with and without tremor are observed This in order to make a subsequent filter that allows to generate mechanical solutions that mitigate the involuntary movements of people with muscular disorders and thus improve their quality of life From the acquired signals, it is observed that the accelerometer in the Z coordinate is the one that is most affected by these oscillatory movements, which is part of this for the design of filters and solutions in future works ACKNOWLEDGEMENT The research for paper was supported by Military University Nueva Granada by research 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Biophysiological Signs of People with Tremor CONCLUSIONS With the analysis of the discrete Fourier transform, the frequency spectra in magnitude and phase of the signals of people with and without tremor. .. editor@iaeme.com Frequency Analysis of Biophysiological Signs of People with Tremor Another estimation method is the linear weighted Fourier combiner that adaptively shakes a tremor signal by tracking its frequency, ... movement and pronation movement 2.2 Frequency Spectrum of People with Tremor Biophysiological signals are acquired through MYO, from people with and without tremor for movement patterns given