Acute effects of thalamic deep brain stimulation and thalamotomy on sensorimotor cortex local field potentials in essential tremor.
OBJECTIVE
Essential tremor (ET) is characterized by an action tremor believed to be due to excessive theta-alpha activity in the cerebello-thalamo-cortical system. This study aimed to test the hypothesis that therapeutic thalamic stimulation in patients with ET decreases theta-alpha oscillatory activity in primary motor (M1) and sensory (S1) cortices.


METHODS
During surgical treatment of ET in 10 patients, an electrocorticography (ECoG) strip electrode was placed temporarily over the arm region of M1 and S1. Local field potentials (LFP) were recorded at rest, during a tremor-inducing posture, during acute therapeutic thalamic stimulation, and following therapeutic thalamotomy (three patients). Power spectral density (PSD) was calculated using the Fast Fourier Transform.


RESULTS
At rest, alpha activity (8-13Hz) in M1 was significantly decreased during high-frequency stimulation, while theta activity (4-8Hz) decreased in S1. Following thalamotomy, theta and beta (13-30Hz) was increased in M1. Induction of postural tremor reduced M1 theta, alpha and beta activity compared to the resting state.


CONCLUSIONS
High-frequency thalamic deep brain stimulation (DBS) significantly reduces alpha oscillatory activity in the primary motor cortex of patients with ET, though this change is probably not critical for therapeutic efficacy.


CONCLUSIONS
We demonstrate that ECoG can be effectively used to study the effect of subcortical stimulation on cortical oscillations.
Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA. ellen.air@uc.edu
Ellen L
EL
Air
Elena
E
Ryapolova-Webb
Coralie
C
de Hemptinne
Jill L
JL
Ostrem
Nicholas B
NB
Galifianakis
Paul S
PS
Larson
Edward F
EF
Chang
Philip A
PA
Starr
D000368:Aged; D000369:Aged, 80 and over; D000513:Alpha Rhythm / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D046690:Deep Brain Stimulation; D004569:Electroencephalography / Q000379:methods*; D058407:Electroencephalography Phase Synchronization; D020329:Essential Tremor / Q000503:physiopathology* / Q000628:therapy*; D005071:Evoked Potentials / Q000502:physiology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D059906:Neuroimaging / Q000379:methods; D013788:Thalamus / Q000503:physiopathology / Q000601:surgery*; D013826:Theta Rhythm / Q000502:physiology; D016896:Treatment Outcome