Open AccessTremor Reduction by Deep Brain Stimulation Is Associated With Gamma Power Suppression in Parkinson's Disease
Author(s) -
Beudel Martijn,
Little Simon,
Pogosyan Alek,
Ashkan Keyoumars,
Foltynie Thomas,
Limousin Patricia,
Zrinzo Ludvic,
Hariz Marwan,
Bogdanovic Marko,
Cheeran Binith,
Green Alexander L.,
Aziz Tipu,
Thevathasan Wesley,
Brown Peter
Publication year - 2015
Publication title -
neuromodulation: technology at the neural interface
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 60
eISSN - 1525-1403
pISSN - 1094-7159
DOI - 10.1111/ner.12297
Subject(s) - deep brain stimulation , subthalamic nucleus , local field potential , stimulation , parkinson's disease , beta rhythm , essential tremor , resting tremor , neuroscience , psychology , electroencephalography , physics , medicine , disease
Objectives Rest tremor is a cardinal symptom of P arkinson's disease ( PD ), and is readily suppressed by deep brain stimulation ( DBS ) of the subthalamic nucleus ( STN ). The therapeutic effect of the latter on bradykinesia and rigidity has been associated with the suppression of exaggerated beta (13–30 Hz) band synchronization in the vicinity of the stimulating electrode, but there is no correlation between beta suppression and tremor amplitude. In the present study, we investigate whether tremor suppression is related to suppression of activities at other frequencies. Materials and Methods We recorded hand tremor and contralateral local field potential ( LFP ) activity from DBS electrodes during stimulation of the STN in 15 hemispheres in 11 patients with PD . DBS was applied with increasing voltages starting at 0.5 V until tremor suppression was achieved or until 4.5 V was reached. Results Tremor was reduced to 48.9% ± 10.9% of that without DBS once stimulation reached 2.5–3 V (t14 = −4.667, p < 0.001). There was a parallel suppression of low gamma (31–45 Hz) power to 92.5% ± 3% (t14 = −2.348, p = 0.034). This was not seen over a band containing tremor frequencies and their harmonic (4–12 Hz), or over the beta band. Moreover, low gamma power correlated with tremor severity (mean r = 0.43 ± 0.14, p = 0.008) within subjects. This was not the case for LFP power in the other two bands. Conclusions Our findings support a relationship between low gamma oscillations and PD tremor, and reinforce the principle that the subthalamic LFP is a rich signal that may contain information about the severity of multiple different Parkinsonian features.