1/2. Parkinsonism following bilateral lesions of the globus pallidus: performance on a variety of motor tasks shows similarities with Parkinson's disease.OBJECTIVES: The authors report the results of detailed investigations into the motor function of a patient who, after a heavy drinking binge and subsequent unconsciousness, respiratory acidosis, and initial recovery, developed parkinsonism characterised by hypophonic speech and palilalia, "fast micrographia", impaired postural reflexes, and brady/akinesia in proximal (but not distal) alternating upper limb movements. methods: In addition to brain magnetic resonance imaging (MRI), different aspects of motor function were investigated using reaction time (RT) tasks, pegboard and finger tapping tasks, flex and squeeze tasks, movement related cortical potentials (MRCPs), and contingent negative variation (CNV). Cognitive function was also assessed. The results were compared to those previously reported in patients with Parkinson's disease (PD). RESULTS: brain MRI showed isolated and bilateral globus pallidus (GP) lesions covering mainly the external parts (GPe). These lesions were most probably secondary to respiratory acidosis, as other investigations failed to reveal an alternative cause. The results of the RT tasks showed that the patient had difficulties in preparing and maintaining preparation for a forthcoming movement. MRCP and CNV studies were in line with this, as the early component of the MRCP and CNV were absent prior to movement. The patient's performance on pegboard and finger tapping, and flex and squeeze tasks was normal when performed with one hand, but clearly deteriorated when using both hands simultaneously or sequentially. CONCLUSIONS: In general, the present results were similar to those reported previously in patients with PD. This provides further indirect evidence that the output of globus pallidus is of major importance in abnormal motor function in PD. The possible similarities of the functional status of GP in PD and our case are discussed.- - - - - - - - - - ranking = 1keywords = globus pallidus, pallidus, globus (Clic here for more details about this article) |
2/2. High-frequency stimulation of the globus pallidus internalis in Parkinson's disease: a study of seven cases.The effectiveness of ventroposterolateral pallidotomy in the treatment of akinesia and rigidity is not a new discovery and agrees with recent investigations into the pathogenesis of Parkinson's disease, which highlight the role played by the unbridled activity of the subthalamic nucleus (STN) and the consequent overactivity of the globus pallidus internalis (GPi). Because high-frequency stimulation can reversibly incapacitate a nerve structure, we applied stimulation to the same target. Seven patients suffering from severe Parkinson's disease (Stages III-V on the Hoehn and Yahr scale) and, particularly, bradykinesia, rigidity, and levodopa-induced dyskinesias underwent unilateral electrode implantation in the posteroventral GPi. Follow-up evaluation using the regular Unified Parkinson's disease Rating Scale has been conducted for 1 year in all seven patients, 2 years in five of them, and 3 years in one. In all cases high-frequency stimulation has alleviated akinesia and rigidity and has generally improved gait and speech disturbances. In some cases tremor was attenuated. In a similar manner, the authors observed a marked diminution in levodopa-induced dyskinesias. This could be an excellent primary therapy for younger patients exhibiting severe bradykinesia, rigidity, and levodopa-induced dyskinesias, which would allow therapists to keep ventroposterolateral pallidotomy in reserve as a second weapon.- - - - - - - - - - ranking = 0.83333333333333keywords = globus pallidus, pallidus, globus (Clic here for more details about this article) |