Tc-99(m)-ECD SPET perfusion changes by internal pallidum stimulation in Parkinson's disease

High-frequency stimulation of the internal pallidum is an effective surgica l approach for patients with advanced Parkinson's disease suffering from mo tor fluctuations and L-dopa induced dyskinesia. To study the acute effects of internal pallidum stimulation, changes in cerebral blood flow were measu red by means of a single-day split-dose protocol using Tc-99(m)-ECD SPET. N ine patients with advanced Parkinson's disease and with a clinical picture predominated by tremor and drug-induced dyskinesia, were imaged before and immediately after electrostimulation Brain perfusion data were mirrored to the same electrode side (five left and four right implants), co-registered and analysed statistically on a voxel-by-voxel basis (Statistical Parametri c Mapping) and by an automated volume-of-interest approach. Acute stimulati on of the internal pallidum induced a significantly decreased perfusion in the ipsilateral thalamus and striatum, as well as in the right parietal cor tex. For the subgroup of seven patients with effective motor score improvem ents, a significant correlation between thalamic and striatal perfusion cha nges and UPDRS III motor score was present (P=0.04). These results suggest that effective stimulation of the internal globus pallidus may produce symp tom relief through decreased activity in pallido-thalamo-cortical circuits. ((C) 2000 Lippincott Williams & Wilkins).