Attenuation of pathological tremors by functional electrical stimulation I: Method

Procházka, A.; Elek, J.; Javidan, Manouchehr

doi:10.1007/bf02368521

Cited by 136 publications

(121 citation statements)

References 13 publications

(3 reference statements)

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“…The large inter-subject variability in the high-pass properties of the MUAP (in particular, standard deviations in cut-off frequency of ~30 Hz) implied that the magnitude of this effect is difficult to predict and that the 7/2/ 7/1 derived from the EMG is therefore not suited for the estimation of the temporal tremor characteristics. The angular velocity, on the other hand, is the result of a low-passed filtered version of the neural drive due to the properties of the motor unit twitch [35,39] and the viscoelastic mechanical properties of muscles [36,46]. Furthermore, this low-pass filtering is highly pronounced in older adults, due to the agerelated slowing of muscle contractile speed [47].…”

Section: Discussionmentioning

confidence: 99%

“…Due to the high levels of motor unit short-term synchronization related to tremor, spike-triggered averaging could not be employed to accurately obtain the shapes of the motor unit twitches [34] to estimate the mechanical filters imposed on the neural drive. This filtering effect, however, has been quantified in several previous studies [35,36].…”

Section: Experimental Data Analysismentioning

confidence: 91%

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One central oscillatory drive is compatible with experimental motor unit behaviour in essential and Parkinsonian tremor

et al. 2015

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Objective. Pathological tremors are symptomatic to several neurological disorders that are difficult to differentiate and the way by which central oscillatory networks entrain tremorogenic contractions is unknown. We considered the alternative hypotheses that tremor arises from one oscillator (at the tremor frequency) or, as suggested by recent findings from the superimposition of two separate inputs (at the tremor frequency and twice that frequency). Approach. Assuming one central oscillatory network we estimated analytically the relative amplitude of the harmonics of the tremor frequency in the motor neuron output for different temporal behaviors of the oscillator. Next, we analyzed the bias in the relative harmonics amplitude introduced by superimposing oscillations at twice the tremor frequency. These findings were validated using experimental measurements of wrist angular velocity and surface electromyography (EMG) from 22 patients (11 essential tremor, 11 Parkinson's disease). The ensemble motor unit action potential trains identified from the EMG represented the neural drive to the muscles. Main results. The analytical results showed that the relative power of the tremor harmonics in the analytical models of the neural drive was determined by the variability and duration of the tremor bursts and the presence of the second oscillator biased this power towards higher values. The experimental findings accurately matched the analytical model assuming one oscillator, indicating a negligible functional role of secondary oscillatory inputs. Furthermore, a significant difference in the relative power of harmonics in the neural drive was found across the patient groups, suggesting a diagnostic value of this measure (classification accuracy: 86%). This diagnostic power decreased substantially when estimated from limb acceleration or the EMG. Signficance. The results indicate that the neural drive in pathological tremor is compatible with one central network providing neural oscillations at the tremor frequency. Moreover, the regularity of this neural oscillation varies across tremor pathologies, making the relative amplitude of tremor harmonics a potential biomarker for diagnostic use.

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Section: Discussionmentioning

confidence: 99%

Section: Experimental Data Analysismentioning

confidence: 91%

One central oscillatory drive is compatible with experimental motor unit behaviour in essential and Parkinsonian tremor

et al. 2015

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“…Before calibrating the model to subjects, the initial values of sensitive contraction parameters were Table 1 Parameters and values of muscle model taken from literatures and were list in Table 1 [3,14]. Based on the optimizing approach, the calibrated values of parameters of each subject were averaged across 3 trails as shown in Table 1.…”

Section: Calibration Of Musculoskeletal Modelmentioning

confidence: 99%

“…The pathological tremor usually occurs in the wrist or elbow joint of patients suffering from Parkinson's disease and significantly weakens the daily activities, such as holding meal spoon or inserting the keys. Recently, Functional Electric Stimulation (FES) was intensively studied to restore the function of pathological extremities [2][3][4][5]. The exploration of the origin of tremor is fundamental to improving the treatments.…”

Section: Introductionmentioning

confidence: 99%

Research on musculoskeletal model of elbow joint for evaluating the feasibility of FES

Wang

Gao

Liu

et al. 2015

BME

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Abstract.Tremor usually occurs in a patient's upper limb with a roughly sinusoidal profile. Understanding the inner mechanism of the involuntary movement is fundamental to improving tremor suppression treatments. Therefore, the musculoskeletal model of the elbow joint was developed in this study. Initially, healthy subjects were selected to simulate tremor and the tremulous data was collected with the purpose of sparing patients from fatigue. With the recorded joint angle and surface EMG (sEMG), the model was calibrated to subjects by optimization approach. The activation derived from the electric pulse was employed to drive the tuned model and the model's output was compared with the angle predicted by the EMG-driven musculoskeletal model. The results demonstrated that the performance of the calibrated model was improved by a smaller normalized root mean square error and a higher coefficient of determination compared with the no-tuned model. There was no significant difference between the angles estimated by the tuned model activated by the electric pulse and muscle excitation. It indicates that neural activation could be replaced by the electric pulse to excite the limbs for desired angle. Therefore, the study presents a good way to evaluate the feasibility of Functional Electric Stimulation to suppress tremor.

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“…New bioengineering therapies are now emerging as viable solutions 2 . In particular, recent studies aim to develop and validate a new treatment for upper limb tremor based on the combination of functional electrical stimulation (FES) with a brain-computer interface (BCI) 2– 3 . The main goal is to set up a semi-automatic procedure to reduce/stop upper limb tremor, with a selective cancellation of tremor oscillations while preserving natural voluntary movement.…”

Section: Introductionmentioning

confidence: 99%

Quality parameters for a multimodal EEG/EMG/kinematic brain-computer interface (BCI) aiming to suppress neurological tremor in upper limbs

2013

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Tremor is the most common movement disorder encountered during daily neurological practice. Tremor in the upper limbs causes functional disability and social inconvenience, impairing daily life activities. The response of tremor to pharmacotherapy is variable. Therefore, a combination of drugs is often required. Surgery is considered when the response to medications is not sufficient. However, about one third of patients are refractory to current treatments. New bioengineering therapies are emerging as possible alternatives. Our study was carried out in the framework of the European project “Tremor” (ICT-2007-224051). The main purpose of this challenging project was to develop and validate a new treatment for upper limb tremor based on the combination of functional electrical stimulation (FES; which has been shown to reduce upper limb tremor) with a brain-computer interface (BCI). A BCI-driven detection of voluntary movement is used to trigger FES in a closed-loop approach. Neurological tremor is detected using a matrix of EMG electrodes and inertial sensors embedded in a wearable textile. The identification of the intentionality of movement is a critical aspect to optimize this complex system. We propose a multimodal detection of the intentionality of movement by fusing signals from EEG, EMG and kinematic sensors (gyroscopes and accelerometry). Parameters of prediction of movement are extracted in order to provide global prediction plots and trigger FES properly. In particular, quality parameters (QPs) for the EEG signals, corticomuscular coherence and event-related desynchronization/synchronization (ERD/ERS) parameters are combined in an original algorithm which takes into account the refractoriness/responsiveness of tremor. A simulation study of the relationship between the threshold of ERD/ERS of artificial EEG traces and the QPs is also provided. Very interestingly, values of QPs were much greater than those obtained for the corticomuscular module alone.

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Attenuation of pathological tremors by functional electrical stimulation I: Method

Abstract: In this study we evaluated a technique for tremor suppression with functional electrical stimulation (FES

Cited by 136 publications

References 13 publications

One central oscillatory drive is compatible with experimental motor unit behaviour in essential and Parkinsonian tremor

One central oscillatory drive is compatible with experimental motor unit behaviour in essential and Parkinsonian tremor

Research on musculoskeletal model of elbow joint for evaluating the feasibility of FES

Quality parameters for a multimodal EEG/EMG/kinematic brain-computer interface (BCI) aiming to suppress neurological tremor in upper limbs

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