Online Tremor Suppression Using Electromyography and Low-Level Electrical Stimulation

Abstract

Tremor is one of the most prevalent movement disorders. There is a large proportion of patients (around 25%) in whom current treatments do not attain a significant tremor reduction. This paper proposes a tremor suppression strategy that detects tremor from the electromyographic signals of the muscles from which tremor originates and counteracts it by delivering electrical stimulation to the antagonist muscles in an out of phase manner. The detection was based on the iterative Hilbert transform and stimulation was delivered above the motor threshold (motor stimulation) and below the motor threshold (sensory stimulation). The system was tested on six patients with predominant wrist flexion/extension tremor (four with Parkinson disease and two with Essential tremor) and led to an average tremor reduction in the range of 46%-81% and 35%-48% across five patients when using the motor and sensory stimulation, respectively. In one patient, the system did not attenuate tremor. These results demonstrate that tremor attenuation might be achieved by delivering electrical stimulation below the motor threshold, preventing muscle fatigue and discomfort for the patients, which sets the basis for the development of an alternative treatment for tremor.

Electrical Stimulation of Afferent Pathways for the Suppression of Pathological Tremor

“…In a recent study (Dosen et al, 2015; Table 1), we observed significant levels of tremor suppression when stimulating muscles below the threshold of direct muscle activation via efferent fibers. This suggests that stimulation of afferent pathways may be an alternative tremor suppression strategy.…”

“…Such treatments, however, can be invasive, expensive, and may not produce effective, long-lasting tremor suppression tremor for all patients. As a potential alternative, studies have suggested the use of external devices to suppress tremor by mechanical loading (Pledgie et al, 2000; Rocon et al, 2007) or electrical stimulation (Javidan et al, 1992; Prochazka et al, 1992; Gillard et al, 1999; Popović Maneski et al, 2011; Gallego et al, 2013; Bó et al, 2014; Dosen et al, 2015). Although the efficacy of both methodologies has been proven, electrical stimulation arguably allows for a more compact and comfortable implementation.…”

“…Overall, two primary stimulation strategies have been applied. The most common strategy ( out-of-phase ) applies electrical stimulation to the muscles so that they generate forces opposite to those arising from the tremorogenic bursts of activity (Javidan et al, 1992; Prochazka et al, 1992; Gillard et al, 1999; Popović Maneski et al, 2011; Dosen et al, 2015). The other strategy ( cocontraction ) provides continuous stimulation simultaneously to antagonist muscles acting about the affected joint in order to increase the stiffness of the joint through co-activation, and thereby filter out the mechanical manifestation (joint oscillations) of the tremorogenic bursts (Grimaldi et al, 2011; Gallego et al, 2013; Bó et al, 2014).…”

“…In the two studies including “other” patients this referred to cerebellar tremor. In three of the studies (Popović Maneski et al, 2011; Bó et al, 2014; Dosen et al, 2015) one subject was excluded from the estimation of the average tremor suppression rate due to a lack of any effect of the stimulation. Thr m denotes motor threshold .…”

Estado del Arte en Neurotecnologías para la Asistencia y la Rehabilitación en España: Tecnologías Fundamentales

“…Aquí cabe destacar el desarrollo de soluciones neuroprotésicas para la supresión de temblores patológicos en el marco de los proyectos europeos TREMOR y NEUROTREMOR, con aproximaciones ligeramente diferentes, en el primer caso mediante estimulación periférica motora (Gallego et al, 2013, Koutsou et al, 2016 y en el segundo caso mediante estimulación periférica sensorial (Dosen et al, 2014;Piazza et al, 2016).…”