The Central Oscillatory Network of Essential Tremor

Department of Neurology, University of Kiel, 24105 Germany.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2010; 2010:154-7. DOI: 10.1109/IEMBS.2010.5627211
Source: PubMed


The responsible pathological mechanisms of essential tremor are not yet clear. In order to understand the mechanisms of the central network its sources need to be found. The cortical sources of both the basic and first "harmonic" frequency of essential tremor are addressed in this paper. The power and coherence were estimated using the multitaper method for EEG and EMG data from 6 essential tremor patients. The Dynamic Imaging of Coherent Sources (DICS) was used to find the coherent sources in the brain. Before hand this method was validated for the application of finding multiple sources for the same oscillation in the brain by using two model simulations which indicated the accuracy of the method. In all the essential tremor patients the corticomuscular coherence was also present in the basic and the first harmonic frequency of the tremor. The source for the basic frequency and the first harmonic frequency was in the region of primary sensory motor cortex, prefrontal and in the diencephalon on the contralateral side for all the patients. Thus the generation of these two oscillations involves the same cortical areas and indicates the oscillation at double the tremor frequency is a harmonic of the basic tremor frequency.

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    • "Additional aspects support the fact that DICS is also sensitive to deep sources. For example, simulation studies showed that a simulated source with a physiological signal-to-noise ratio placed in the diencephalon could be located correctly by DICS [59,60]. Moreover, different control calculations demonstrated a high reliability of DICS for the detection of deep sources: 1) Analysis of randomly chosen EEG segments of no interest (baseline) did not reveal the same coherent network as for EEGs segments with seizures; 2) Shifting the first source within the coherent network, for example to the thalamus, revealed the same coherent sources, whereas shifting of the first source to any other brain area destroyed the coherent network of sources (for a detailed description see 60. "
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