Subthalamic nucleus stimulation reduces abnormal motor cortical overactivity in Parkinson disease.
BACKGROUND
Based on the basal ganglia model, it has been hypothesized that the efficacy of high-frequency stimulation of the subthalamic nucleus (STN) against parkinsonian symptoms relies on the activation of cortical premotor regions. In previous positron emission tomography activation studies, STN high-frequency stimulation was associated with selective activation of midline premotor areas during hand movements but mainly reduced the regional cerebral blood flow in movement-related areas, peculiarly at rest.


OBJECTIVE
To investigate with positron emission tomography the role of regional cerebral blood flow reduction in the clinical improvement provided by STN high-frequency stimulation.


METHODS
Seven patients with advanced Parkinson disease, who were markedly improved by bilateral STN high-frequency stimulation, underwent positron emission tomography with H2(15)O while the right STN electrode was turned off. The patients were studied at rest and during right-hand movements in 3 electrode conditions: no stimulation, inefficient low-frequency stimulation, and efficient high-frequency stimulation.


RESULTS
The main effect of high-frequency stimulation was to reduce regional cerebral blood flow in the left primary sensorimotor cortex, the lateral premotor cortex, the right cerebellum, and the midline premotor areas. The selective activation of the anterior cingulate cortex and the left primary sensorimotor cortex during hand movement under STN high-frequency stimulation was attributed to decreased regional cerebral blood flow at rest, rather than increased activation induced by STN high-frequency stimulation. Akinesia was correlated with the abnormal overactivity in the contralateral primary sensorimotor cortex and the ipsilateral cerebellum.


CONCLUSIONS
High-frequency stimulation of the STN acts through the reduction of abnormal resting overactivity in the motor system, allowing selective cortical activation during movement.
Institut National de la Santé et de la Recherche Médicale U455, Toulouse, France. payoux.p@chu-toulouse.fr
Pierre
P
Payoux
Philippe
P
Remy
Philipe
P
Damier
Malika
M
Miloudi
Isabelle
I
Loubinoux
Bernard
B
Pidoux
Véronique
V
Gaura
Olivier
O
Rascol
Yves
Y
Samson
Yves
Y
Agid
D000368:Aged; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply / Q000503:physiopathology*; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D020531:Subthalamic Nucleus / Q000502:physiology*; D014055:Tomography, Emission-Computed / Q000379:methods