Essential tremor and cerebellar dysfunction Clinical and kinematic analysis of intention tremor

Deuschl, Günther; Wenzelburger, Roland; Löffler, Kerstin; Raethjen, Jan; Stolze, Henning

doi:10.1093/brain/123.8.1568

Cited by 346 publications

(278 citation statements)

References 55 publications

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“…The feedback signal through the afferent pathway might have affected the cerebrum, which was suggested to be the source of tremor [4,11]. Reflex on the spinal level evoked by the electrical stimulation [19] might have reduced the efferent motor commands to the muscles related to the tremor.…”

Section: Discussionmentioning

confidence: 99%

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Sensory electrical stimulation for suppression of postural tremor in patients with essential tremor

Heo

Kim

Kwon

et al. 2015

BME

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Abstract. Essential tremor is an involuntary trembling of body limbs in people without tremor-related disease. In previous study, suppression of tremor by sensory electrical stimulation was confirmed on the index finger. This study investigates the effect of sensory stimulation on multiple segments and joints of the upper limb. It denotes the observation regarding the effect's continuity after halting the stimulation. 18 patients with essential tremor (8 men and 10 women) participated in this study. The task, "arms stretched forward", was performed and sensory electrical stimulation was applied on four muscles of the upper limb (Flexor Carpi Radialis, Extensor Carpi Radialis, Biceps Brachii, and Triceps Brachii) for 15 seconds. Three 3-D gyro sensors were used to measure the angular velocities of segments (finger, hand, and forearm) and joints (metacarpophalangeal and wrist joints) for three phases of pre-stimulation (Pre), during-stimulation (On), and 5 minute poststimulation (P5). Three characteristic variables of root-mean-squared angular velocity, peak power, and peak power frequency were derived from the vector sum of the sensor signals. At On phase, RMS velocity was reduced from Pre in all segments and joints while peak power was reduced from Pre in all segments and joints except for forearm segment. Sensory stimulation showed no effect on peak power frequency. All variables at P5 were similar to those at On at all segments and joints. The decrease of peak power of the index finger was noted by 90% during stimulation from that of On phase, which was maintained even after 5 min. The results indicate that sensory stimulation may be an effective clinical method to treat the essential tremor.

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Section: Discussionmentioning

confidence: 99%

“…Essential tremor occurs in 0.3-1.7% of the world's population, 5.5% of 40 to 64 year old, and 10.2% of 65 year olds or over [2]. Important symptoms of essential tremor include postural tremor and action tremor [1,[3][4]. Traditional treatment of essential tremor includes medication and surgery.…”

Section: Introductionmentioning

confidence: 99%

Sensory electrical stimulation for suppression of postural tremor in patients with essential tremor

Heo

Kim

Kwon

et al. 2015

BME

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“…The impact of essential tremor on premovement MRP has not been explored. It has been proposed that ET patients may have cerebellar abnormalities (Deuschl et al, 2000), although this may mainly involve abnormal input to the cerebellum from the inferior olive, whereas the cerebellar output pathway to the thalamus appears to be intact (Pinto et al, 2003). Moreover, almost all patients had significant scalp BP and CNV, indicating the neural processes underlying these potentials are active.…”

Section: Implications For Pdmentioning

confidence: 99%

Involvement of the Basal Ganglia and Cerebellar Motor Pathways in the Preparation of Self-Initiated and Externally Triggered Movements in Humans

Purzner

Paradiso²,

Cunic³

et al. 2007

J. Neurosci.

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The subthalamic nucleus (STN) is part of the cortico-basal ganglia (BG)-thalamocortical circuit, whereas the ventral lateral nucleus of the thalamus (VL) is a relay nucleus in the cerebello-dentato-thalamocortical (CTC) pathway. Both pathways have been implicated in movement preparation. We compared the involvement of the STN and VL in movement preparation in humans by recording local field potentials (LFPs) from seven patients with Parkinson's disease with deep-brain stimulation (DBS) electrodes in the STN and five patients with tremor and electrodes in VL. LFPs were recorded from DBS electrodes and scalp electrodes simultaneously while the patients performed self-paced and externally cued (ready, go/no-go) movements. For the self-paced movement, a premovement-related potential was observed in all patients from scalp, STN (phase reversal, five of six patients), and VL (phase reversal, five of five patients) electrodes. The onset times of the potentials were similar in the cortex, STN, and VL, ranging from 1.5 to 2 s before electromyogram onset. For the externally cued movement, an expectancy potential was observed in all patients in cortical and STN electrodes (phase reversal, six of six patients). The expectancy potential was recorded from the thalamic electrodes in four of five patients. However, phase reversal occurred only in one case, and magnetic resonance imaging showed that this contact was outside the VL. The cortico-BG-thalamocortical circuit is involved in the preparation of both self-paced and externally cued movements. The CTC pathway is involved in the preparation of self-paced but not externally cued movements, although the pathway may still be involved in the execution of these movements.

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“…It is characterized by an involuntary and rhythmic tremor of patients' limbs, most typically the hands and arms [30].…”

Section: Biomedical Applicationsmentioning

confidence: 99%

Joint Angle Tracking with Inertial Sensors

El‐Gohary¹

2000

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The need to characterize normal and pathological human movement has consistently driven researchers to develop new tracking devices and to improve movement analysis systems. Movement has traditionally been captured by either optical, magnetic, mechanical, structured light, or acoustic systems. All of these systems have inherent limitations. Optical systems are costly, require fixed cameras in a controlled environment, and suffer from problems of occlusion. Similarly, acoustic and structured light systems suffer from the occlusion problem. Magnetic and radio frequency systems suffer from electromagnetic disturbances, noise and multipath problems. Mechanical systems have physical constraints that limit the natural body movement.Recently, the availability of low-cost wearable inertial sensors containing accelerometers, gyroscopes, and magnetometers has provided an alternative means to overcome the limitations of other motion capture systems. Inertial sensors can be used to track human movement in and outside of a laboratory, cannot be occluded, and are low cost. To calculate changes in orientation, researchers often integrate the angular velocity. However, a relatively small error or drift in the measured angular velocity leads to large integration errors. This restricts the time of accurate measurement and tracking to a few seconds. To compensate that drift, complementary data from accelerometers and magnetometers are normally integrated in tracking systems that utilize the Kalman filter (KF) or the extended Kalman filter (EKF) to fuse the nonlinear inertial data. Orientation estimates are only accurate for brief moments when the body is not moving and acceleration is only due to gravity. Moreover, sucii cess of using magnetometers to compensate drift about the vertical axis is limited by magnetic field disturbance.We combine kinematic models designed for control of robotic arms with state space methods to estimate angles of the human shoulder and elbow using two wireless wearable inertial measurement units. The same method can be used to track movement of other joints using a minimal sensor configuration with one sensor on each segment. Each limb is modeled as one kinematic chain. Velocity and acceleration are recursively tracked and propagated from one limb segment to another using Newton-Euler equations implemented in state space form. To mitigate the effect of sensor drift on the tracking accuracy, our system incorporates natural physical constraints on the range of motion for each joint, models gyroscope and accelerometer random drift, and uses zero-velocity updates. The combined effect of imposing physical constraints on state estimates and modeling the sensor random drift results in superior joint angles estimates. The tracker utilizes the unscented Kalman filter (UKF) which is an improvement to the EKF. This removes the need for linearization of the system equations which introduces tracking errors.We validate the performance of the inertial tracking system over long durations of slow, normal, and ...

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Essential tremor and cerebellar dysfunction Clinical and kinematic analysis of intention tremor

Cited by 346 publications

References 55 publications

Sensory electrical stimulation for suppression of postural tremor in patients with essential tremor

Sensory electrical stimulation for suppression of postural tremor in patients with essential tremor

Involvement of the Basal Ganglia and Cerebellar Motor Pathways in the Preparation of Self-Initiated and Externally Triggered Movements in Humans

Joint Angle Tracking with Inertial Sensors

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