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CURRENT SCIENCE REVIEWS By Joe Bruman December 1997 p. 1 of 2 Tronnier V et al; J Neurosurg 1997;807:700-705: In 6 patients given bilateral pallidal stimulation implants, they report good improvement in dyskinesia, but only slight improvement in gait disturbance and bradykinesia. Stimulation worsened gait disturbance by creating a freezing phenomenon. So they question whether DBS is a good alternative to conventional pallidotomy. Gill S, Heywood P; Lancet, 25 Oct 1997:1224: They dislike DBS implants because the devices are bulky and costly, need replacement in 3-5 yr and frequent adjustment, preclude further MRI scans, and may lose effectiveness over time. They report safe and effective conventional ablative surgery for 2 PD patients at a new site (bilateral, microrecorder-guided): the dorsolateral area of the subthalamic nucleus. Both were able to quit dopamine therapy. Vals-Sole J et al; Brain 1997;120:1877-1883: Peculiar lack of blink reflex to a certain electrical stimulus is a diagnostic distinction of progressive supranuclear palsy (PSP) from PD and other parkinsonian syndromes. Juncos J, Delong M; Sci Amer Medicine 11;Chap. XV:Nov 1997: An 18-page chapter on PD and basal ganglia movement disorders, in the Neurology section of a huge loose-leaf collection published and updated sporadically for medical libraries by Scientific American. This chapter, by two noted authorities, is the most comprehensive and timely summary yet seen of what is known about PD. Barbato L et al; Clin Neuropharm 1997;20:394-401: Levodopa therapy in PD seems to have both a short-term effect, dependent on most recent dosage, and a longer-term effect dependent on a slower-changing "baseline" concentration of dopamine. Low baseline level may be responsible for motor fluctuations observed in long-term therapy. They tested combinations of Sinemet and Ropinerole, concluding that the long-term action of levodopa may be due to a postsynaptic effect. van Hilten J et al; Clin Neuropharm 1997;20:402-408: To determine a threshold of dopaminergic response of bradykinesia, they observed tap rate and movement time in PD patients given apomorphine, concluding that 15% gain in tap rate is a suitable diagnostic criterion of effectiveness. Contin M et al; Clin Neuropharm 1997;20:409-418: In a 3-yr test of response to levodopa in 11 PD patients, the duration of effect on tap rate declined, but that of effect on dyskinesia showed only minor change, suggesting that the various effects of levodopa therapy are mediated in different ways. Del Dotto P et al; Clin Neuropharm 1997;20:455-465: An 8-week test of the non-ergot-derived dopamine agonist Cabergoline as adjunct to levodopa, on 10 new PD patients and 12 advanced (fluctuating) patients, showed it to be effective treatment for either class of patient. CURRENT SCIENCE REVIEWS By Joe Bruman December 1997 p. 2 of 2 Tresilian J et al; Brain 1997;120:2093-2111: They measured reach-and-grasp performance of PD patients, who were about 30% slower than controls. But increasing complexity by doing separate left- and right-hand tasks at once, or requiring greater accuracy, didn't change the ratio. Higher (effector-independent) levels of motor programming are preserved in PD. Parkinson Study Group; Ann Neur 1997;42:747-755: A 24-week controlled trial in 205 fluctuating PD patients of the COMT inhibitor Entacapone showed it to be effective in raising "on" duration and reducing motor fluctuations due to the "wearing- off" effect, and well tolerated. Hutchison W et al; Ann Neur 1997;42:767-775: Fourteen generous pallidotomy recipients endured 80 additional minutes in the Leksell frame for the sake of research. To confirm a result previously found in MPTP monkeys, that the main symptoms of PD result from reduced activity of the external globus pallidus and overactivity in its internal region, researchers monitored 15 specific neurons using the microelectrode recording technique of the pallidotomy procedure. After observing the imbalance, injection of the fast-acting dopamine agonist apomorphine restored the normal balance within 25 to 35 minutes. Then at t=80 minutes the imbalance in neural firing rate returned to its initial state, supporting this new insight into the pathology of PD. Martignoni E et al; Clin Neuropharm 1996;19(1):72-80: In a group of PD patients widely disparate in age, disease stage, and treatment status, they found that the short-term effects of levodopa on pituitary hormone secretion and the long-term suppression of basal levels by terguride (a partial D2 agonist derived from lisuride, of minimal effect on PD symptoms but strong and persistent effect on pituitary function) to be independent. They therefore conclude that even though dopamine is involved, regulation of pituitary function by the hypothalamus is spared in PD. -- J. R. Bruman (818) 789-3694 3527 Cody Road Sherman Oaks, CA 91403-5013