Real-Time Estimation of Pathological Tremor Parameters from Gyroscope Data

Gallego, Juan Álvaro; Rocón, Eduardo; Roa, Javier; Moreno, Juan C.; Pons, José L

doi:10.3390/s100302129

Cited by 94 publications

(99 citation statements)

References 39 publications

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“…Wrist angular velocity was recorded with a pair of solidstate gyroscopes (Technaid S.L., Madrid, Spain) placed on the hand dorsum and the distal third of the forearm (dorsal side), following recommendations from previous studies [28,29]. Data were sampled at 100 Hz by a 12 bit A/D converter and low-pass filtered (5th order Butterworth, cut-off frequency: 20 Hz).…”

Section: Methodsmentioning

confidence: 99%

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: Methodsmentioning

confidence: 99%

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

et al. 2015

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“…Among them, the difference in the energy of the higher tremor harmonics in movement recordings, typically performed with inertial sensors, best discriminates ET and PD patients [17,18]. These harmonics are usually computed after using relatively simple frequency filtering techniques which separate the higher tremor frequencies from the relatively low frequencies of voluntary movement [14,15,17,19]. However, the tremulous movement is nonlinearly related to the underlying muscle activation and results from complicated interactions among the many muscles that control the same joint.…”

Section: Complexitymentioning

confidence: 99%

New Perspectives for Computer-Aided Discrimination of Parkinson’s Disease and Essential Tremor

et al. 2017

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Pathological tremor is a common but highly complex movement disorder, affecting ∼5% of population older than 65 years. Different methodologies have been proposed for its quantification. Nevertheless, the discrimination between Parkinson's disease tremor and essential tremor remains a daunting clinical challenge, greatly impacting patient treatment and basic research. Here, we propose and compare several movement-based and electromyography-based tremor quantification metrics. For the latter, we identified individual motor unit discharge patterns from high-density surface electromyograms and characterized the neural drive to a single muscle and how it relates to other affected muscles in 27 Parkinson's disease and 27 essential tremor patients. We also computed several metrics from the literature. The most discriminative metrics were the symmetry of the neural drive to muscles, motor unit synchronization, and the mean log power of the tremor harmonics in movement recordings. Noteworthily, the first two most discriminative metrics were proposed in this study. We then used decision tree modelling to find the most discriminative combinations of individual metrics, which increased the accuracy of tremor type discrimination to 94%. In summary, the proposed neural drive-based metrics were the most accurate at discriminating and characterizing the two most common pathological tremor types.

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“…1) was implemented as follows. First, the raw motion, recorded with a pair of solid-state gyroscopes, was separated into concomitant voluntary movement and tremor, using a two-stage adaptive algorithm [11]. Next, to obtain accurate information about which muscle needed to be stimulated, the tremor obtained from the solid-state gyroscopes was differentiated, to compute the angular acceleration.…”

Section: Tremor Suppression Strategymentioning

confidence: 99%

“…Trial order was randomized, and the experiment designed using an optimal algorithm [12]. Hand rotation was measured with a pair of solid state gyroscopes (Technaid S.L., Madrid, Spain) placed in differential configuration [11]. Neurostimulation was delivered with a multichannel monopolar stimulator that injected charge compensated pulses (UNA Systems, Belgrade, Serbia); the common electrode was placed at the dorsal side of the wrist.…”

Section: A Assessment Of the Electromechanical Delaymentioning

confidence: 99%

Closed-Loop Modulation of a Notch-Filter Stimulation Strategy for Tremor Management with a Neuroprosthesis

et al. 2014

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Abstract-Tremor is the most common movement disorder, and one of the major causes of functional disability. In spite of the existence of various treatments, tremor is not managed effectively in a large number of patients, which make it a major cause of loss of quality of life. Here we present a novel strategy for tremor suppression through neurostimulation that replicates an adaptive notch-filter at the frequency of the tremor. The controller, which adapts the neurostimulation to the ongoing amplitude, frequency and phase of the tremor, is implemented in a wearable neuroprosthesis for tremor management. Experimental results in one patient with severe essential tremor illustrate the interest of the approach.

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Real-Time Estimation of Pathological Tremor Parameters from Gyroscope Data

Cited by 94 publications

References 39 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

New Perspectives for Computer-Aided Discrimination of Parkinson’s Disease and Essential Tremor

Closed-Loop Modulation of a Notch-Filter Stimulation Strategy for Tremor Management with a Neuroprosthesis

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