Post: 011215

Morens D et al; Neur 1996;46:1044-1050:
Pursuing the hypothesis that PD incidence is lower in Asians than Caucasians, authors tracked a cohort of 8006 American men of Japanese or Okinawan ancestry, born between 1900 and 1919, living in Hawaii, for 29 years. Although PD was associated with markedly shorter lifespan, there was no firm evidence for different incidence of PD.

Djaldetti R et al; Neur 1996;46:1051-1054:
Authors tested 15 PD patients having symptom fluctuations and 15 without, and found delayed gastric emptying, probably affecting levodopa absorption, to be more marked in those with response fluctuations.

Contin M et al; Neur 1996;46:1055-1058:
Length of the short-time (hours) response to levodopa appears to diminish with progression of PD. Authors confirmed that by finger-tapping tests on 66 PD patients.

Pahwa R et al; Neur 1996;46:1059-1062:
Early morning end-of-dose akinesia is prolonged by slow absorption of Sinemet CR. One remedy is to break the morning CR tablet in half, thus increasing its surface area. Another is to start with a regular Sinemet tablet whose effect "kicks in" as soon as 15 to 30 minutes, and follow with the CR tablet 2 hours later. Authors confirmed that by double-blind, placebo-controlled, crossover study of plasma concentration and motor performance in 15 PD patients with early-morning akinesia.

Hutton J et al; Neur 1996;46:1062-1065:
Randomized, placebo-controlled, double-blind test of the long-lasting dopamine agonist cabergoline in 188 patients on levodopa-carbidopa showed it to be effective in reducing motor fluctuations and levodopa requirement, and to be well tolerated. Its effect lasts much longer than that of bromocryptine, pergolide, or lisuride.

Hubble J et al; Neur 1996;46:1150-1153:
Authors report significant reduction of essential tremor (ET) by chronic stimulation of the left Vim thalamic nucleus, using the Medtronic implanted device. Benefits in 10 ET patients were still present 6 months later, while the common complications of thalamotomy were avoided.

Goyal R, Hirano I; NEJM, 25 Apr 1996:1106-1115:
Review of the enteric nervous system, which functions independent of the central nervous system and may be affected in PD. Authors list many neurotransmitters of the enteric ns but, curiously, omit dopamine.

Jankovic J et al; Neur 1995;45:645-648:
Essential tremor is common in families of PD patients, and the two seem to be associated. PD patients with ET live significantly longer than those without.

Goetz C et al; Neur 1995;45:669-671:
PD patients in nursing homes are more likely to have hallucinations and die sooner than those in community dwellings.

Tison F et al; Neur 1995;45:705-708:
Among 4050 elderly people surveyed, dementia was 8 times more likely in PD patients living at home, and even more likely in those that were institutionalized.

Dogali M et al; Neur 1995;45:753-761:
In 18 pallidotomy recipients whose drug therapy had failed, PD symptoms and dyskinesia improved. Medical requirements were unchanged, but better tolerated because of reduced dyskinesia.

Pahwa R et al; Neur 1995;45:822-824:
Ten patients with intractable essential head tremor were improved by botulinum toxin injections.

Baloh R et al; Neur 1995;46:458-460:
In one large family, migraine seems to be inherited, with links to vertigo and essential tremor. All symptoms improved by actazolamide (Diamox).

Friedman J et al; Ann Neur 1996;39:535-538:
Authors did posteroventral pallidotomy on 4 patients with advanced PD, using the promising noninvasive gamma knife rather than conventional stereotactic surgery. Although MRI scans later confirmed the lesion target accuracy, 3 of the 4 patients suffered no clear effects, good or bad. In the 4th, contralateral dyskinesia completely resolved, but he also became transiently demented and psychotic. Authors speculate on possible reasons for the failures.

Eidelberg D et al; Ann Neur 1996;39:450-459:
Stereotactic unilateral pallidotomy in 10 advanced PD cases was followed by PET scans to show regional changes of metabolism. Clinical improvement has persisted up to 2 years, although mechanism of the ablation technique is still not well understood. Significant metabolic changes occurred in several regions remote from the lesion site.

Science News; 18 May 1996:311 (news item):
In aging mice, oxidative free radicals were found in specific areas of the brain whose functions were most impaired, the level rising with age.

Enzensberger W, Fischer P; Lancet; 11 May 1996:1337:
Metronome was best among 4 sources of periodic stimuli in improving gait of 22 PD patients, who liked it as well. It raised speed, lengthened stride, and reduced freezing incidents.

Volkmann J et al; Neur 1996;46:1359-1370:
Authors used electromagnetic detection combined with MRI to locate site of oscillation that procuces resting tremor in 7 PD patients, in areas of the frontal and parietal cortex.

Hely M et al; J Neur Neurosurg Psy 1996:60:531-538:
Diffuse Lewy body disease (DLBD) looks like PD at first but also includes dementia, either at onset or later in progression.

Luft-Johansen M et al; J Neur Neurosurg Psy 1996;60:564-571:
Fifty thalamotomy subjects had some cognitive impairment compared to healthy controls, but the thalamotomy didn't reduce it further.

Pramstaller P, Lees A; J Neur Neurosurg Psy 1996;60:589:
Patient who developed PD 42 years after childhood encephalitis also showed some symptoms of progressive supranuclear palsy (PSP).

Damier P et al; Neur 1996;46:1262-1269:
Although MAO-B may convert MPTP into the toxin MPP, its presence in dopaminergic neurons (studied by immunohistochemistry) doesn't contribute to vulnerability in PD. Moreover, it might even protect against oxidative stress induced by dopamine metabolism.

Morens D et al; Neur 1996;46:1270-1274:
In 30-yr study of 8006 elderly men, authors found some protection against PD from eating legumes (peas, beans) but not from Vitamin E supplements.

Seidler A et al; Neur 1996;46:1275-1284:
Authors studied 380 rural German PD patients and 379 controls for risks of various factors, finding some correlation with pesticides and wood preservatives but not with others. They also found significant familial connections in the PD group, and inverse correlation with smoking.

Barclay C et al; Neur 1996;1284-1286:
Authors tried electroconvulsive therapy (ECT) in 5 PSP patients and found dramatic improvement in one, mild improvement in two, and no improvement in two. All five had transient confusion but no permanent side effects.

Tedroff J et al; Neur 1996;46:1430-1436:
Authors used PET to measure levodopa-induced changes in synaptic dopamine in 10 PD patients. They speculate that the levodopa-related complications of advanced PD are due to excessive amine turnover in the denervated striatum.

Papa S, Chase T; Ann Neur 1996;39:574-578:
The experimental glutamate antagonist LY235959 in MPTP monkeys seems to potentiate the effects of levodopa on PD symptoms while reducing the dyskinesia complications.

Arendt J; BMJ, 18 May 1996:1242-1243:
Melatonin, the hormone of the pineal gland, is strictly controlled by prescription in the UK, but freely available in the USA. consequently it is used by millions of Americans for a large variety of supposed benefits. Melatonin does relieve temporary insomnia or jet lag, and has had numerous trials for other objectives, but claims that it is an antioxidant, immunostimulant, contraceptive, prevents aging, improves cardiovascular and sexual function, or cures AD or AIDS, are premature.

Greenamyre J; Ann Neur 1996;39:557-558:
A class of drugs called glutamate receptor antagonists interferes with the glutamatergic subthalamic nucleus, whose overactivity projected to the globus pallidus in turn causes symptoms of parkinsonism. Those drugs include amantadine, memantine, and budipine, as well as the experimental drug LY235959 (see part 3). Experimenters found that such antagonists administered either stereotactically or systemically can reduce the amount of levodopa required to control primary symptoms of PD, while at the same time they suppress the levodopa-induced dyskinesia of advanced PD. Thus it appears that drugs may possibly substitute for surgical pallidotomy or pallidal stimulation. Moreover, glutamate antagonists may have a neuroprotective effect that slows progression of PD. Further testing awaits advent of more specific and better-tolerated compounds.

Louis E, Ottman R; Neur 1996;46:1200-1205:
Etiology and prevalence of essential tremor remain obscure. Estimates range as high as 20 times the prevalence of PD. Some PET studies link ET to increased cerebellar activity. There is inconclusive evidence of genetic susceptibility.

Boeker H et al; Ann Neur 1996;39:650-658:
Authors used PET scans to assess the geographic effect of ethanol on essential tremor in 6 ET patients and 6 controls. Ethanol reduced blood flow to the cerebellum in all subjects, leading to suppression of tremor in the ET patients. The suppression is mediated via reduction of cerebellar synaptic overactivity which causes increased afferent input to the inferior olivary nuclei.