Kinetic tremor in a reach-to-grasp movement in Parkinson's disease

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

doi:10.1002/1531-8257(200011)15:6<1084::aid-mds1005>3.0.co;2-y

Cited by 48 publications

(23 citation statements)

References 44 publications

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“…nesia in PD patients is mostly due to an underestimation of the size of the necessary impulsive force, or to a limitation in the mechanism that produces the motor commands. Our results are consistent with this second view and suggest that motor signals are constrained into a preset dynamic range in both patients and controls, but that this range is pathologically narrow in PD (with in some patients the superposition of some tremor oscillations on the motor commands; Lance et al, 1963, Brown et al, 1997, Wenzelburger et al, 2000 Theoretically, a narrowing of the range of motor commands predicts, among other things, a correct scaling of EMG with movement amplitude but with a lower rate of rise of muscle activity. Note, however, that peak motor command does not generally correspond to a maximum effort; it was the case here since movements were of self-determined speed.…”

Section: Discussionmentioning

confidence: 99%

A Common Optimization Principle for Motor Execution in Healthy Subjects and Parkinsonian Patients

et al. 2013

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Recent research on Parkinson's disease (PD) has emphasized that parkinsonian movement, although bradykinetic, shares many attributes with healthy behavior. This observation led to the suggestion that bradykinesia in PD could be due to a reduction in motor motivation. This hypothesis can be tested in the framework of optimal control theory, which accounts for many characteristics of healthy human movement while providing a link between the motor behavior and a cost/benefit trade-off. This approach offers the opportunity to interpret movement deficits of PD patients in the light of a computational theory of normal motor control. We studied 14 PD patients with bilateral subthalamic nucleus (STN) stimulation and 16 age-matched healthy controls, and tested whether reaching movements were governed by similar rules in these two groups. A single optimal control model accounted for the reaching movements of healthy subjects and PD patients, whatever the condition of STN stimulation (on or off). The choice of movement speed was explained in all subjects by the existence of a preset dynamic range for the motor signals. This range was idiosyncratic and applied to all movements regardless of their amplitude. In PD patients this dynamic range was abnormally narrow and correlated with bradykinesia. STN stimulation reduced bradykinesia and widened this range in all patients, but did not restore it to a normal value. These results, consistent with the motor motivation hypothesis, suggest that constrained optimization of motor effort is the main determinant of movement planning (choice of speed) and movement production, in both healthy and PD subjects.

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Section: Discussionmentioning

confidence: 99%

A Common Optimization Principle for Motor Execution in Healthy Subjects and Parkinsonian Patients

et al. 2013

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“…Since one of the recruitment criteria of our study was to recruit healthy individuals without neurological impairments and who did not take medications that may increase or decrease tremor, we could not get enough subjects for the group G7 during the period of the research. [13][14][15]17,[23][24][25]28,33,35,36 Task Definition…”

Section: Criteria For Recruitment Of Subjects and Definition Of Groupsmentioning

confidence: 99%

“…25,29,34 As the main focus of this study is to investigate the specific-task physiological tremor it makes sense to limit the bandwidth of the signal to the range of interest as suggested in other investigations. 15,17,36 Therefore, we applied a linear filter in order to obtain the physiological tremor activity for analysis. This activity was filtered by using a fourth-order digital band-pass Butterworth filter.…”

Section: Data Pre-processingmentioning

confidence: 99%

“…[12][13][14][15]17,20,24,30,35 However, even with the advances in the technology of digitizing tablets, which allowed for more precision and accuracy in the measurement of movements, no study focusing upon the use of these devices, as a tool for investigating the relation between physiological tremor and aging in kinetic conditions, was found in our literature survey. Although some authors, e.g., Wenzelburger et al, 36 support the hypothesis that kinetic tremor is related to an enhancement of physiological tremor this assumption is not consensual 11,29,33 and therefore additional studies in this area are required.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Age-Related Changes in Physiological Kinetic Tremor

et al. 2010

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Tremor is the most common movement disorder characterized by repetitive and stereotyped movements. Most investigations on tremor attempt to understand its relation to neuromuscular dysfunctions. Therefore, there is a lack of studies that aim to investigate the complex relation between the physiological tremor and aging, especially in kinetic conditions. In this context, the main motivation of this research was to quantify age-related changes in the kinetic tremor of clinically healthy individuals. For this, a number of features extracted from tremor activity, obtained from digitized drawings of Archimedes' spirals, were analyzed. In total, 59 subjects participated in the experiments. These individuals were divided into seven groups according to their ages and two types of analysis were carried out. First, the tremor activity of young and elderly adults was investigated by means of traditional features commonly used in tremor analysis, and secondly, linear discriminant analysis (LDA) was employed for the study of the correlation between age and tremor. The results showed significant statistical differences between the kinetic tremor activity of the young and elderly groups. Furthermore, it was found that LDA allowed for the estimate of a unique feature, so-called LDA-value, which showed to be linearly correlated with age.

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“…PD tremor is classically described as a low-frequency (3.5-6.5 Hz) asymmetric pill-rolling resting tremor of the limbs different than essential tremor or physiological tremor. It is generally accepted that PD tremor is centrally originated but may be more complex, involving more than one neurological circuit (Findley et al, 1981;Forssberg et al, 2000;Wenzelburger et al, 2000). Currently, pharmacological management of PD primarily involves the use of dopaminergic replacement therapy.…”

Section: Introductionmentioning

confidence: 99%