Common and unique responses to dopamine agonist therapy and deep brain stimulation in Parkinson's disease: an H(2)(15)O PET study.
BACKGROUND
Dopamine agonist therapy and deep brain stimulation (DBS) of the subthalamic nucleus (STN) are antiparkinsonian treatments that act on a different part of the basal ganglia-thalamocortical motor circuitry, yet produce similar symptomatic improvements.


OBJECTIVE
The purpose of this study was to identify common and unique brain network features of these standard treatments.


METHODS
We analyzed images produced by H(2)(15)O positron emission tomography (PET) of patients with Parkinson's disease (PD) at rest. Nine patients were scanned before and after injection of apomorphine, and 11 patients were scanned while bilateral stimulators were off and while they were on.


RESULTS
Both treatments produced common deactivations of the neocortical sensorimotor areas, including the supplementary motor area, precentral gyrus, and postcentral gyrus, and in subcortical structures, including the putamen and cerebellum. We observed concomitant activations of the superior parietal lobule and the midbrain in the region of the substantia nigra/STN. We also detected unique, treatment-specific changes with possible motor-related consequences in the basal ganglia, thalamus, neocortical sensorimotor cortex, and posterolateral cerebellum. Unique changes in nonmotor regions may reflect treatment-specific effects on verbal fluency and limbic functions.


CONCLUSIONS
Many of the common effects of these treatments are consistent with the standard pathophysiologic model of PD. However, the common effects in the cerebellum are not readily explained by the model. Consistent deactivation of the cerebellum is interesting in light of recent reports of synaptic pathways directly connecting the cerebellum and basal ganglia, and may warrant further consideration for incorporation into the model.
Language Section, Voice, Speech, and Language Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA.
Trent J
TJ
Bradberry
Leonard Verhagen
LV
Metman
José L
JL
Contreras-Vidal
Pepijn
P
van den Munckhof
Lara A
LA
Hosey
Jennifer L W
JL
Thompson
Geralyn M
GM
Schulz
Fredrick
F
Lenz
Rajesh
R
Pahwa
Kelly E
KE
Lyons
Allen R
AR
Braun
D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D001058:Apomorphine / Q000627:therapeutic use*; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D046690:Deep Brain Stimulation; D018491:Dopamine Agonists / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000628:therapy*; D011877:Radionuclide Imaging; D016896:Treatment Outcome
D000978:Antiparkinson Agents; D018491:Dopamine Agonists; D001058:Apomorphine