L-DOPA biotransformation: correlations of dosage, erythrocyte catechol O-methyltransferase and platelet SULT1A3 activities with metabolic pathways in Parkinsonian patients.

The objectives of this study were to determine (1) the effects of dose and drug absorption on pathways of biotransformation of L-DOPA in Parkinsonian patients treated with Sinemet, and (2) the extent to which genetically-determined variations in the activities of erythrocyte catechol O-methyltransferase and/or platelet phenol sulfotransferase might be reflected in individual differences in L-DOPA metabolism. In the 19 patients studied, there were negative correlations between dosage or absorption and extent of O-methylation and of sulfation of L-DOPA or its metabolites. Levels of activity for erythrocyte COMT were also reflected in individual variation in the metabolism of L-DOPA. In contrast, differences in platelet phenol sulfotransferase were not reflected in differences in sulfation of L-DOPA or of its metabolites. If such a relationship did exist, it might have been obscured by the effects of high dosage of L-DOPA, effects which might have resulted from a deficiency of the sulfation cosubstrate 3'-phosphoadenosine 5'-phosphosulfate in patients taking higher doses of drug.

Neuropathology of two members of a German-American kindred (Family C) with late onset parkinsonism.

We present genealogical and longitudinal clinical observations and autopsy findings of a previously reported kindred, Family C (German-American), with late-onset autosomal dominant parkinsonism with evidence for linkage on chromosome 2p13. The clinical phenotype includes the cardinal features of idiopathic Parkinson's disease. In addition, postural tremor and dementia are detected in some individuals. Two members of the kindred, one affected and one unaffected have recently come to autopsy. The unaffected family member was an 82-year-old woman whose brain showed only mild age-related pathology and no evidence of subclinical Lewy body disease. In contrast, the affected family member was an 83-year-old man whose brain had neuronal loss, gliosis and Lewy bodies in the substantia nigra and other monoaminergic brain stem nuclei, as well as the basal forebrain and amygdala. Lewy bodies and Lewy neurites had a distribution typical of cases of idiopathic Parkinson's disease. Thus, the clinical and pathological findings in this family with autosomal dominant parkinsonism are similar to those of sporadic Parkinson's disease.

Frequency of levodopa-related dyskinesias and motor fluctuations as estimated from the cumulative literature.

There is no clear consensus regarding the frequency (and hence, the risk), of dyskinesias or motor fluctuations during chronic levodopa therapy for Parkinson's disease (PD). Multiple clinical series have tabulated these frequencies since the advent of levodopa over 30 years ago. We were interested in determining: (1) the aggregate frequency figures in the existing literature; and (2) how clinical series from the early levodopa era, which included patients with longer durations of parkinsonism, compare to more recent (modern era) series. We searched MEDLINE for all English language publications reporting the cumulative frequency of levodopa-induced dyskinesias or motor fluctuations during discrete intervals of treatment. This generated 2,478 publications spanning 1966 through September 2000. Papers with appropriate titles or abstracts were reviewed; reference lists from published clinical series were a source of additional papers for review. This ultimately yielded 74 publications with adequate data, relating to 112 intervals of levodopa treatment. Series that included patients with PD-onset well before levodopa availability (pre-levodopa era) were separately analyzed from all subsequent series. Series were grouped by duration of levodopa therapy and the median frequencies of dyskinesias and motor fluctuations were tabulated for each group. The data were analyzed both with and without adjustment for the number (N) in each series. Among series containing pre-levodopa era patients, the median dyskinesia frequency was already 50% by 5-6 months of treatment. This contrasts with the modern era series where dyskinesias were reported later in treatment. The median dyskinesia frequency was slightly less than 40% by 4-6 years of levodopa therapy among modern era patients. Motor fluctuations (wearing-off) were not tabulated in most of the early levodopa series. Among modern era reports, motor fluctuations were nil during the first year of levodopa therapy but were experienced by approximately 40% of patients by 4-6 years of treatment. Similar results were found when the analyses were restricted to only prospective studies where levodopa motor complications were targeted outcome measures. The conclusions reached were: (1) patients from the pre-levodopa era experienced dyskinesias much earlier during levodopa treatment than modern era patients, perhaps because of longer durations of pre-existing PD; (2) in the present era, patients treated with levodopa therapy for 4-6 years have approximately a 40% likelihood of experiencing motor fluctuations and a risk of dyskinesias just short of 40%; and (3) these findings represent incident data and the prevalence of clinically important morbidity may be substantially less.

Motor unit changes in sporadic idiopathic Parkinson's disease.

We studied motor unit changes in 20 patients with Parkinson's disease (PD) and 20 age-matched control subjects to look for evidence of motorneuron degeneration in sporadic idiopathic PD. Patients and control subjects were screened by clinical criteria and nerve conduction studies to exclude those with peripheral neuropathic processes. Changes in motor unit morphology were investigated with subjective and computerized quantitative electromyography (QEMG) of the anterior tibialis (AT) and first dorsal interosseous. Multivariate comparisons showed a significant difference in the QEMG analysis for motor unit enlargement in patients with PD versus control subjects. Some of the univariate comparisons for both the subjective and QEMG analyses of the AT were also significant. These results demonstrate that motorneuron drop-out with reinnervation occurs in sporadic idiopathic PD. In summary, our findings provide evidence that clinically silent motorneuron disease occurs in typical cases of sporadic idiopathic PD, suggesting that it may be a normal part of the pathologic picture of PD. Any hypothesis concerning the pathogenic mechanism of PD would need to take into account such a finding.

Electrophysiological observations in hereditary parkinsonism-dementia with Lewy body pathology.

We studied the only two living affected individuals who are part of a previously reported kindred that expresses a hereditary parkinsonism-dementia syndrome with Lewy body pathology. The electrophysiological characteristics of the hyperkinetic movement disorders in these patients were examined to provide physiological insights into the clinical phenotype of this syndrome. Evaluation of both patients showed 7-9 Hz electromyographic discharges in upper extremity muscles during postural activation, and one patient showed a 4-5 Hz discharge pattern correlating to a rest tremor. Brief (<50 ms) myoclonic electromyographic discharges were seen in both patients, and a time-locked relationship to a focal cortical premovement electroencephalographic potential was elicited in one patient. Somatosensory evoked potentials were not enlarged and long latency reflexes were not enhanced. Electroencephalography was normal in one patient but showed pathologic slow frequencies in the other. The electrophysiological findings show evolution which correlates with an apparent characteristic evolution of hyperkinetic movement disorders that accompanies the severe progression of parkinsonism-dementia in this kindred. These results have implications for the future study of this and similar syndromes.

Long-term follow-up of levodopa responsiveness in generalized dystonia.

OBJECTIVES: To assign an accurate diagnosis to patients with dystonia based on the presence of sustained levodopa responsiveness and to determine whether motor fluctuations occur in patients with dystonia who are withheld from levodopa. PATIENTS AND METHODS: Patients with generalized dystonia who responded to treatment in the 1970s with levodopa/carbidopa were surveyed by phone and then examined during a 3-day levodopa holiday. Functional imaging with fluorodopa positron emission tomography was performed on a subset of patients. RESULTS: In the phone interview, 4 of 7 patients with a diagnosis of dopa-responsive dystonia reported the wearing-off effect a short while (within 4-8 hours) after missing a dose of levodopa. Five patients with dopa-responsive dystonia were examined repetitively during levodopa withdrawal, and 3 developed recurrent symptoms of dystonia as the drug was withheld. In each case, worsening of dystonia did not occur until 29 hours or more after levodopa withdrawal, providing evidence for a response profile similar to the long duration response described in Parkinson disease. No significant changes were seen in the dystonia scores of the 3 patients with idiopathic torsion dystonia who were withheld from levodopa. CONCLUSIONS: We suggest that the subjective feeling of wearing off experienced by our patients with dopa-responsive dystonia may have been for one of the nonmotor effects of levodopa, such as mood elevation. Our data provide objective evidence for the often-repeated assertion that motor fluctuations (analogous to those in levodopa-treated patients with Parkinson disease) do not occur in patients with dopa-responsive dystonia.

Hereditary form of parkinsonism--dementia.

In four generations of a family, 13 members were afflicted with an autosomal dominant disorder characterized by young age at onset, early weight loss, and rapidly progressive dopa-responsive parkinsonism, followed later by dementia and, in some, by hypotension. Intellectual dysfunction began with subjective memory loss and objective visuospatial dysfunction and was followed later by decline of frontal lobe cognitive and memory functions. Neuropathological examination in 4 autopsied cases showed neuronal loss in the substantia nigra and locus ceruleus and widespread Lewy bodies, many of them in the cerebral cortex; those in the hypothalamus and locus ceruleus were often of bizarre shapes. Other findings were vacuolation of the temporal cortex, unusual neuronal loss and gliosis in the hippocampus (CA 2/3), and neuronal loss in the nucleus basalis. There were no neuritic plaques, neurofibrillary tangles, or amyloid deposits. Positron emission tomography in 3 patients showed decreased striatal uptake of fluorodopa. Neurochemical analysis of an autopsied brain showed a pronounced decrease in choline acetyltransferase activity in the frontal and temporal cortices and hippocampus and a severe depletion of striatal dopamine with a pattern not typical of classic Parkinson's disease.

Cortical myoclonus in levodopa-responsive parkinsonism.

We observed myoclonic movements of the fingers and wrists in two patients with a levodopa-responsive parkinsonian syndrome most consistent with Parkinson's disease. These patients were studied with electrophysiological techniques. Brief (<50 ms) myoclonic electromyographic discharges showed a time-locked relationship to a focal premovement electroencephalographic potential. Somatosensory-evoked potentials were not enlarged and long-latency reflexes were not grossly exaggerated. This pattern of electrophysiological findings can be distinguished from those previously found in other parkinsonian syndromes. These results provide evidence for a cortical origin of the myoclonus seen in these patients.

Adjunctive cabergoline therapy of Parkinson's disease: comparison with placebo and assessment of dose responses and duration of effect.

Adjunctive cabergoline or placebo, in doses up to 5 mg daily, were administered to Parkinson's disease patients with short-duration levodopa responses in a 6-month double-blind trial. The 13 patients randomized to cabergoline and completing the study had significantly improved Unified Parkinson's Disease Rating Scale (UPDRS) motor scores and timed hand-tapping test scores. Serial measurements on test days documented improved scores: (a) before the first levodopa (and cabergoline) dose of the day, (b) at the time of the peak levodopa effect, and (c) at the end of the levodopa response cycle, 5 h after test doses. Continued testing verified that these therapeutic responses were sustained for at least 48 h after the last cabergoline dose. Patients randomized to placebo failed to improve on any of these measures. In a subsequent open-label dose-escalation phase, further improvement was documented as the dosage was gradually raised to 10 mg daily. As in the double-blind phase, levodopa reduction allowed the improvement to occur in the absence of significantly increased dyskinesias. Other side effects were more substantial with higher doses, however, including two of 11 patients with hallucinations and confusion. In summary, adjunctive single-daily-dose cabergoline therapy resulted in long-lasting, dose-related improvement in parkinsonism not seen in patients receiving placebo.

Multicenter, placebo-controlled trial of cabergoline taken once daily in the treatment of Parkinson's disease.

Cabergoline is a dopaminergic agonist relatively specific for the D2 receptor and much longer-acting than other dopamine agonists. We conducted a randomized, placebo-controlled, double-blind study of cabergoline in 188 levodopa/carbidopa-treated patients with suboptimally controlled Parkinson's disease (PD). The cabergoline patients had significantly better Activities of Daily Living (p = 0.032) and Motor Examination (p = 0.031) scores at the conclusion of the trial compared with the placebo group. The daily levodopa dose for the cabergoline patients decreased 18% compared with a 3% reduction for the placebo group (p < 0.001). The amount of time in the "on" state increased more in the cabergoline group (p = 0.022). The side-effect was similar to that seen with other dopamine agonists, and cabergoline was generally well tolerated. We conclude that cabergoline is an effective adjunct to levodopa for the treatment of PD.

Aphysiologic performance on dynamic posturography.

The remarkable ability of the body to maintain balance is the result of central nervous system integration of sophisticated inputs from the vestibular, visual, and somatosensory systems. Strategies by patients with balance dysfunction are aphysiologic when their performance is relatively better on more difficult conditions of sensory conflict than on easier ones. Twenty-two aphysiologic patterns on computerized dynamic posturography were compared with age-matched normal and vestibular patterns. The aphysiologic group performed significantly better than the patients in the vestibular dysfunction group on the most difficult subtests of computerized dynamic posturography, conditions 5 and 6, yet significantly poorer on the easier subtests, conditions 1 through 4. In addition, patients in the aphysiologic group tended to show greater intertrial variability compared with patients in both normal and vestibular system dysfunction groups. A stepwise linear discriminant analysis was used to determine a set of conditions that had significant value in discriminating between the three patient groups. Case studies are presented to further illustrate the clinical usefulness of computerized dynamic posturography testing in the evaluation of patients suspected of having a functional component to their on-feet balance problems.

Fluctuating Parkinson's disease. Treatment with the long-acting dopamine agonist cabergoline.

OBJECTIVE: Assessment of the very long-acting dopamine agonist medication cabergoline in the control of motor fluctuations in Parkinson's disease. DESIGN: Open-label trial (13 weeks). SETTING: Referral centers (Mayo Clinic, Rochester, Minn, and Scottsdale, Ariz). PATIENTS: Volunteer sample of 41 patients with idiopathic Parkinson's disease who were experiencing motor fluctuations while receiving stable doses of carbidopa and levodopa. INTERVENTION: Adjunctive oral cabergoline was incrementally administered once daily with the maintenance dose determined by the clinical response (maximum dose, 5 mg/d). MAIN OUTCOME MEASURES: Standardized serial motor examinations were performed, beginning anywhere from 30 minutes before and continuing to 6 hours after test doses of medications were administered. Scores during adjunctive cabergoline therapy were compared with the prestudy baseline scores during therapy with carbidopa and levodopa without cabergoline. RESULTS: Adjunctive cabergoline therapy significantly improved mean motor scores at the time of each standardized serial examination, from 30 minutes to 6 hours after the administration of test doses of medications. Significant motor score improvement was also measured 24 hours after the last cabergoline dose was administered, suggesting a very long-acting antiparkinsonian effect. Mean dyskinesia scores were slightly but nonsignificantly elevated. Diary card "off-time" was improved by 42%, whereas the levodopa dosage was reduced by 18%. Only three patients dropped out (7% of the total), which contrasts with much higher dropout rates owing to adverse events in previous clinical trials of other antiparkinsonian dopamine agonists. CONCLUSIONS: Cabergoline improved motor control in patients with Parkinson's disease who were experiencing clinical fluctuations. Possible advantages of this medication include an extended clinical response (persisting to 24 hours), tolerability, and ease of use (once per day administration).

Levodopa therapy and survival in idiopathic Parkinson's disease: Olmsted County project.

We studied survival in all Olmsted County Parkinson's disease (PD) patients seen at the Mayo Clinic from 1964 to 1978, attempting to answer two questions: (1) What effect does levodopa have on survival in PD? and (2) Does the timing of levodopa administration influence survival? We chose this period because it allowed us to study patient records with a spectrum of disease durations before levodopa treatment; in many patients, the treatment delay was exclusively due to levodopa being unavailable prior to 1969. Mortality of the entire PD cohort (N = 179; 61% levodopa-treated) was greater than that of the general population (matched chronologically, geographically, and by age and gender). Lower age at onset of motor symptoms, lower Hoehn and Yahr stage at first neurologic visit for parkinsonism, and treatment with levodopa were all independent predictors of improved survival. Using a time-dependent Cox regression model, we assessed the impact of the timing of levodopa administration during the course of illness on mortality, while statistically controlling for other factors (ie, patient selection for levodopa treatment, and independent predictors of survival). Risk of death following initiation of levodopa was significantly reduced (p < 0.001), regardless of pre-levodopa duration of illness. This reduction gradually diminished over a period of 4 years on levodopa, but continued to be significantly reduced. After 4 years, increasing survival benefit again progressively accrued over time to at least 17 years of levodopa treatment (p < 0.001). At no point in time was levodopa treatment associated with increased mortality, arguing against substantial levodopa toxicity. However, despite levodopa-improved survival, mortality continues to be increased in PD relative to the general population.

Dopamine agonist treatment of fluctuating parkinsonism. D-2 (controlled-release MK-458) vs combined D-1 and D-2 (pergolide)

Adjunctive treatment with the very potent and selective dopamine D-2 agonist MK-458 (controlled-release formulation) improved the control of parkinsonism in patients with fluctuating responses to levodopa therapy (with carbidopa). We subsequently switched patients to adjunctive treatment with pergolide, a less potent D-2 agonist. Pergolide therapy controlled parkinsonism more effectively than controlled-release MK-458. Unlike MK-458, pergolide mesylate also has D-1 agonist properties, apparently accounting for its greater antiparkinsonism efficacy. Adjunctive treatment with controlled-release MK-458 elicited less choreiform dyskinesias than either pergolide adjunctive therapy or therapy with carbidopa-levodopa alone; this finding suggests that D-1 receptor stimulation contributes to the elicitation of medication-induced chorea. The highest doses of controlled-release MK-458 resulted in paradoxical freezing of gait in almost one third of patients. This finding suggests that gait freezing, common in untreated parkinsonism, can also be elicited by excessive D-2 stimulation.

Treatment of essential tremor with methazolamide.

We treated 28 patients (16 women and 12 men) who had essential tremor with methazolamide. Their median age was 69 years (range, 34 to 89 years), and the median duration of tremor was 16 years (range, less than 1 to 69 years). Fifteen cases were familial and 13 were sporadic. Improvement in 10 patients who continued taking the drug ranged from moderate to complete relief. In addition, four patients had marked improvement and two had moderate improvement but discontinued use of the drug because of side effects. Five patients with a mild response and seven with no response also discontinued methazolamide therapy. The maximal mean daily dose was 203 mg for all patients and 129 mg (maintenance dose) for the patients who continued taking the drug. Side effects consisted primarily of somnolence, nausea, epigastric discomfort, anorexia, paresthesias, and numbness. No aplastic anemia was noted in any of the patients. The median duration of follow-up was 6 months (range, 10 weeks to 29 months). The therapeutic effect seemed unrelated to a family history of tremor, the effect of alcohol, or the responsiveness to propranolol or primidone. Methazolamide may be an effective drug in the treatment of some patients with essential tremor, particularly those with head and voice tremor.

Parkinson's disease monotherapy with controlled-release MK-458 (PHNO): double-blind study and comparison to carbidopa/levodopa.

The potent and selective dopamine D-2 agonist, MK-458 [PHNO; (+)-4-propyl-9-hydroxynaphthoxazine] was administered as monotherapy to nine patients with Parkinson's disease in a double-blind, placebo-controlled 12-week investigation; ten other patients were randomized to placebo. MK-458 was formulated as a controlled-release preparation, using a hydroxypropyl methylcellulose-lactase (HPMC) matrix. Patients receiving MK-458/HPMC improved on a variety of measures of parkinsonism, compared to their baseline scores; in contrast, only trivial improvement was seen within the placebo group. We subsequently compared the anti-Parkinson response to MK-458/HPMC with the response to chronic carbidopa/levodopa monotherapy in an open label trial. Carbidopa/levodopa improved parkinsonism to a significantly greater degree than MK-458/HPMC. Doses of MK-458 used in these studies (up to 60 mg per day) were substantially higher than those in previously reported preliminary studies of this medication. We conclude that monotherapy with MK-458/HPMC results in a significant anti-Parkinson effect; however, the response falls short of that seen with carbidopa/levodopa.

An unusual cause of recurrent chorea.

Recurrent chorea is described in a 61-year-old woman who had had chorea gravidarum when she was younger. The recurrent chorea appeared to be induced by a topical vaginal cream that contained conjugated estrogen. This case is consistent with the existence of a recurrent syndrome of hormone-induced chorea. The effect of estrogen on the basal ganglia is complex and not fully understood.

An examination of male-female differences in progression and mortality of Parkinson's disease.

We conducted disability and mortality studies to determine if the male preponderance usually found in Parkinson's disease (PD) was reflected in different courses of the diseases in the 2 sexes. We analyzed longitudinal disability score in 47 men and 23 women with PD followed for 6 years at UCLA. We found no significant differences between the sexes in mean disability scores in any of the 6 years. Mean dopa dosage was significantly higher in men, possibly reflecting their generally larger body mass. Choreoathetosis, dementia, or other side effects did not differ between the 2 groups. We obtained observed to expected mortality ratios in 239 men and 132 women followed for 3,831 person-years from records of 4 medical centers. Using the sex-specific US Life Tables to calculate expected mortality, we found the observed to expected ratio for the men was 1.7457 and for the women 2.4740, a significantly greater excess in female mortality. Analyses of mortality using tables which are not sex-specific will fail to uncover the decreased longevity in women with PD. We conclude that, despite the male preponderance in PD, men and women acquire it at the same age, have the same progression and duration of disease, and die at the same age; whereas, in the general population, women have a longer life expectancy than men. It is not known what factors protect women from incurring PD and what lowers their life expectancy to that of men when they do have the disease.