Characteristics of hand tremor time series

Timmer, Jens; Gantert, C.; Deuschl, Günther; Honerkamp, Josef

doi:10.1007/bf00202568

Cited by 109 publications

(51 citation statements)

References 12 publications

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“…63 Several studies demonstrated absent frequency reduction after loading of the trembling limb in PD patients. 33,64 Another series of studies has dealt with resetting of the rhythm of parkinsonian tremor after different stimuli as mechanical perturbations, 65 electrical stimulation of the median nerve, 66,67 or transcranial magnetic stimulation of the motor cortex. 68 The results did not show a consistent resetting of the tremor rhythm when stimulating the periphery but a complete resetting when the cortex was stimulated.…”

Section: Contribution Of Reflex Pathwaysmentioning

confidence: 99%

Pathophysiology of Parkinson's disease: From clinical neurology to basic neuroscience and back

Bergman¹,

Deuschl²

2002

Mov Disord.

270

190

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Parkinson's disease (PD) is characterized by motor and nonmotor (cognitive and limbic) deficits. The motor signs of PD include hypokinetic signs such as akinesia/bradykinesia, rigidity and loss of normal postural reflexes, and hyperkinetic signs such as tremor. Dopamine depletion in the striatum is the hallmark of PD and of its animal models, still the pathophysiology of the parkinsonian symptoms and especially of parkinsonian tremor are under debate. The most extreme hypotheses argue about peripheral versus central nervous system origin, intrinsic cellular oscillator versus network oscillators, and basal ganglia-based pathophysiology versus cerebellar-thalamic based pathophysiology. Recent studies support the view that parkinsonian symptoms are most likely due to abnormal synchronous oscillating neuronal activity within the basal ganglia. Peripheral factors do only play a minor role for the generation, maintenance, and modulation of PD tremor and other signs. The most likely candidates producing these neuronal oscillations are the weakly coupled neural networks of the basal ganglia-thalamo-cortical loops. However, the present evidence supports the view that the basal ganglia loops are influenced by other neuronal structures and systems and that the tuning of these loops by cerebello-thalamic mechanisms and by other modulator neurotransmitter systems entrain the abnormal synchronized oscillations. Neurosurgical procedures, such as lesions or high-frequency stimulation of different parts of the loop, might resume the normal unsynchronized activity of the basal ganglia circuitry, and, therefore, ameliorate the clinical symptoms of Parkinson's disease.

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Section: Contribution Of Reflex Pathwaysmentioning

confidence: 99%

Pathophysiology of Parkinson's disease: From clinical neurology to basic neuroscience and back

Bergman¹,

Deuschl²

2002

Mov Disord.

270

190

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“…It is an adapted version of the fourth statistical moment proposed by Timmer et al [1993] and corresponds to the mean absolute values of tremor time series (with their mean set to zero [Beuter et al, 2003]). See Figure 5 for further explanation.…”

Section: For Postural and Kinetic Tremorsmentioning

confidence: 99%

Effect of a low intensity magnetic field on human motor behavior

Legros

Beuter²

2005

Bioelectromagnetics

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Extremely low frequency (ELF) magnetic fields (MF) are omnipresent in our modern daily environment, but their effects on humans are still not clearly established. The aim of this study was to determine the effect of a 50 Hz, 1,000 microT MF centered at the level of the head on human index finger micro-displacements. Twenty-four men recruited among the personnel of the French company, Electricité de France (EDF), completed the experiment. Their postural and kinetic tremors were recorded under four "field-on" and four "field-off" conditions, each tested during a real and a sham sequence. Eight postural and four kinetic tremor characteristics were calculated on recorded time series and were used for statistical analysis. No effect of the MF was found for kinetic tremor. Concerning postural tremor, the proportion of oscillations at low frequencies (between 2 and 4 Hz) was higher during the real than during the sham exposure sequence (P<.05). It suggests that MF could have a subtle delayed effect on human behavior, which is clearly not pathological. These results should be taken into account for the establishment of new exposure limits.

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“…For instance, linear analyses may also reveal aspects of nonlinear coupling in ET (Timmer et al, 1993. Furthermore, nonlinear interdependencies are not necessarily superior but rather assess distinct aspects of signal coupling.…”

Section: Methodological Considerationsmentioning

confidence: 99%

Thalamomuscular Coherence in Essential Tremor: Hen or Egg in the Emergence of Tremor?

Pedrosa¹,

Quatuor²,

Reck³

et al. 2014

J. Neurosci.

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Thalamomuscular coherence in essential tremor (ET) has consistently been detected in numerous neurophysiological studies. Thereby, spatial properties of coherence indicate a differentiated, somatotopic organization; so far, however, little attention has been paid to temporal aspects of this interdependency. Further insight into the relationship between tremor onset and the onset of coherence could pave the way to more efficient deep brain stimulation (DBS) algorithms for tremor. We studied 10 severely affected ET patients (six females, four males) during surgery for DBS-electrode implantation and simultaneously recorded local field potentials (LFPs) and surface electromyographic signals (EMGs) from the extensor and flexor muscles of the contralateral forearm during its elevation. The temporal relationship between the onset of significant wavelet cross spectrum (WCS) and tremor onset was determined. Moreover, we examined the influence of electrode location within one recording depth on this latency and the coincidence of coherence and tremor for depths with strong overall coherence ("tremor clusters") and those without. Data analysis revealed tremor onset occurring 220 Ϯ 460 ms before the start of significant LFP-EMG coherence. Furthermore, we could detect an anterolateral gradient of WCS onset within one recording depth. Finally, the coincidence of tremor and coherence was significantly higher in tremor clusters. We conclude that tremor onset precedes the beginning of coherence. Besides, within one recording depth there is a spread of the tremor signal. This reflects the importance of somatosensory feedback for ET and questions the suitability of thalamomuscular coherence as a biomarker for "closedloop" DBS systems to prevent tremor emergence.

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Characteristics of hand tremor time series

Cited by 109 publications

References 12 publications

Pathophysiology of Parkinson's disease: From clinical neurology to basic neuroscience and back

Pathophysiology of Parkinson's disease: From clinical neurology to basic neuroscience and back

Effect of a low intensity magnetic field on human motor behavior

Thalamomuscular Coherence in Essential Tremor: Hen or Egg in the Emergence of Tremor?

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