Recent pathophysiological models of Parkinson's disease have led to new surgical approaches to treatment including deep brain stimulation (DBS) and lesioning of basal ganglia structures. Various measures of upper limb akinesia were assessed in 6 patients with bilateral DBS of the internal pallidum and 6 with DBS of the subthalamic nucleus. Stimulation improved a number of aspects of motor function, and particularly movement time, and force production. Time to initiate movements, and to perform repetitive movements also improved but less dramatically. Processes indicating preparatory motor processes showed no significant change. Few significant differences were found between the internal pallidum and subthalamic nucleus groups. In general, the effects of DBS closely parallel previous reports of the effects of dopaminergic medication. It is suggested that disrupted pallidal output in Parkinson's disease interferes with the rate, level, and coordination of force production but has little effect on preparatory processes. The similarity of the effects of subthalamic nucleus and internal pallidum stimulation suggests this disrupted outflow is the most important determinant of upper limb akinesia in Parkinson's disease. The effects of DBS were similar to the effects of unilateral pallidal lesions reported elsewhere. Ann Neurol 1999;45:473–488

Article abstract-The authors report a patient with postischemic parkinsonism who responded neither to levodopa nor to bilateral subthalamic nucleus (STN) stimulation. MRI revealed bilateral lesions of the substantia nigra, the striatum, the external pallidum, and part of the internal pallidum. PET showed reduced striatal dopa-decarboxylase activity, D 2 receptor binding, and glucose metabolism. 2,3 A single case report indicates a positive effect of pallidotomy in a patient with postischemic parkinsonism, in whom the lesions involved the putamen and the globus pallidus externus bilaterally but spared the globus pallidus internus. 4 Another patient with levodopa-resistant parkinsonism with a normal preoperative MRI and mildly reduced 18 F-fluorodopa PET improved after pallidotomy. 5 We report the case of a patient with a postischemic akineto-rigid parkinsonian syndrome, unresponsive to L-dopa, who showed only a minor response to bilateral STN stimulation.Case report. A 63-year-old man experienced syncope. He was immediately diagnosed with cardiac arrest and received cardiac massage and mouth-to-mouth respiration. Ventricular fibrillation was diagnosed on arrival at the hospital 25 minutes later. Electrical defibrillation restored a sinus rhythm. He regained consciousness, but had generalized tonic-clonic seizures, which were treated with high doses of barbiturates. A barbiturate coma was maintained over 10 days and ventilation was prolonged because of pulmonary infection. Although cognitive functions were quickly recovered, he was left with a severe postischemic akinetic-rigid syndrome that was stable over time. There was no subjective or objective improvement under levodopa (600 mg ϩ decarboxylase inhibitor per day) for 18 months and no deterioration when levodopa was stopped. Administration of subcutaneous apomorphine up to 8 mg as a bolus did not induce any change in the motor state. Before surgery, the parkinsonian syndrome was rated 65/ 108 on the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS). He had severe generalized akinesia and rigidity, mild action tremor of the upper limbs, severe hypophonic speech, frequent choking when swallowing liquids, and loss of postural reflexes. He was able to get out of a chair and walk unassisted, but gait was greatly impaired by initiation difficulties, festination, and freezing. There were no motor fluctuations or dyskinesias. There was no dementia, but neuropsychological examination revealed mild difficulties in tests sensitive to frontal lobe scoring. No definite signs of pyramidal, sensory, or cerebellar involvement were found. MRI revealed bilateral lesions of the basal ganglia with a hypointense signal on T2-and a hyperintense signal on T1-weighted sequences, mainly of the putamen and caudate but also involving the globus pallidus, sparing its most internal part. Mild hyperintense signals were also seen lateral to the interpeduncular cistern in the substantia nigra (figure). Striatal measurements of dopa-decarboxylase activity (fluorodopa PET), D ...