Disordered respiration as a levodopa-induced dyskinesia in Parkinson's disease.

Symptomatic respiratory disturbance as a consequence of levodopa (L-dopa) therapy for Parkinson's disease (PD) has been described only rarely and may be underrecognized in clinical practice. We report on two patients with PD in whom the introduction or augmentation of L-dopa therapy was associated with the development of irregular and rapid breathing. Analysis of breathing patterns before and after L-dopa demonstrated a striking change in respiratory rate after administration of L-dopa, with the emergence of irregular tachypnea alternating with brief periods of apnea, in a pattern consistent with a central origin. In both cases, the temporal relationship of the respiratory disturbance to the administration of L-dopa suggested a peak-dose drug effect. Previous reports of L-dopa-induced respiratory dyskinesia are reviewed, and the potential mechanisms whereby L-dopa might influence the central control of respiration to produce irregular breathing patterns are discussed.     

Early piribedil monotherapy of Parkinson's disease: A planned seven-month report of the REGAIN study.

Piribedil is a D2 dopamine agonist, which has been shown to improve symptoms of Parkinson's disease (PD) when combined with L-dopa. The objective of this study was to compare the efficacy of piribedil monotherapy to placebo in patients with early PD over a 7-month period. Four hundred and five early PD patients were randomized (double-blind) to piribedil (150-300 mg/day) or placebo. L-dopa open-label supplementation was permitted. Unified Parkinson Disease Rating Scale part III (UPDRS III) score as the last observation on monotherapy over 7 months was the primary outcome measure. Secondary outcomes were proportion of responders (UPDRS III improvement > 30%), patients remaining on monotherapy after 7 months, UPDRS III subscores, and UPDRS II. UPDRS III improved on piribedil (-4.9 points) versus a worsening on placebo (2.6 points; estimated effect = 7.26 points; 95% CI = 5.38-9.14; P < 0.0001). The proportion of responders was significantly higher for piribedil (42%) than for placebo (14%) (OR = 4.69; 95% CI = 2.82-7.80; P < 0.001). Piribedil significantly improved several UPDRS III subscores. UPDRS II improved on piribedil by -1.2 points, while it deteriorated by 1.5 points on placebo (estimated effect = 2.71; 95% CI = 1.8-3.62; P < 0.0001). The proportion of patients remaining on monotherapy after 7 months was greater in the piribedil group (OR = 3.72; 95% CI = 2.26-6.11; P < 0.001). Safety was consistent with that reported for other dopamine agonists, gastrointestinal side effects being the most common (22% of patients in piribedil group vs. 14% on placebo). Piribedil is effective and safe as early PD therapy.     

Efficacy of piribedil as early combination to levodopa in patients with stable Parkinson's disease: a 6-month, randomized, placebo-controlled study.

Piribedil is a non-ergot D2/D3 agonist with a significant antagonist action on alpha2A and alpha2C adrenergic receptor subtypes. This double-blind placebo-controlled study was undertaken to confirm the efficacy of 150 mg/day piribedil po in improving motor symptoms of idiopathic Parkinson's disease (PD) in nonfluctuating patients insufficiently controlled by a stable daily dose of levodopa (L-dopa). Efficacy was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) III score as primary criterion over 4 months. A second comparison was planned at 6 months, after possible adjustment of L-dopa. At 4 months, the rate of response, defined as a 30% decrease from baseline on UPDRS III score, was significantly greater with piribedil compared with placebo (56.4% vs. 37.7%; P = 0.040). At 6 months, the better efficacy of piribedil was maintained (61.8% of responders vs. 39.6% on placebo; P = 0.020). The difference between groups on UPDRS III change from baseline reached statistical significance only at 6 months: -10.0 points in the piribedil group vs. -6.7 points in the placebo group (P = 0.037). Secondary end-points were not significantly different. The most frequently reported adverse events were gastrointestinal symptoms (27 of 61 patients in the piribedil group vs. 13 of 54 patients in the placebo group). In conclusion, a 6-month oral administration of 150 mg/day piribedil in combination with L-dopa is well tolerated, except for minor gastrointestinal symptoms at the beginning of the treatment and significantly improves motor symptoms compared with placebo in PD nonfluctuating patients.     

Helicobacter pylori infection and motor fluctuations in patients with Parkinson's disease

To investigate whether Helicobacter pylori (HP) infection affects the clinical response to levodopa and whether its eradication could improve motor fluctuation in patients with Parkinson's disease (PD). Using the [¹³C] urea breath test, we monitored HP infection in 65 patients with PD and motor fluctuations of the “wearing‐off” or delayed “on” types, with or without dyskinesia. We compared the clinical features and response to L ‐dopa between HP noninfected (n = 30) and HP infected patients (n = 35) by reviewing home diaries kept for 72 hours. Among HP infected patients, we compared the differences in L ‐dopa “onset” time, “on‐time” duration, and scores on the motor examination section of the Unified PD Rating Scale (UPDRS‐III) during the medication “on” phase before and after HP eradication. There were no differences in the age, disease duration, Hoehn and Yahr stage, UPDRS‐III score, L ‐dopa daily dose, and frequency of dyskinesia between HP noninfected and HP infected groups. However, L ‐dopa “onset” time was longer and “on‐time” duration was shorter in HP infected patients than in HP noninfected patients (78.4 ± 28.2 vs. 56.7 ± 25.1 and 210.0 ± 75.7 vs. 257.7 ± 68.9 min, respectively, P < 0.05). HP eradication improved the delay L ‐dopa “onset” time and short “on‐time” duration (to 58.1 ± 25.6 and to 234.4 ± 66.5 min, respectively, P < 0.05). These data demonstrated that HP infection could interfere with the absorption of L ‐dopa and provoke motor fluctuations. HP eradication can improve the motor fluctuations of HP infected patients with PD. © 2008 Movement Disorder Society     

Influence of pallidal stimulation and levodopa on gait and preparatory postural adjustments in Parkinson's disease.

In order to assess the influence of the bilateral internal globus pallidus (GPi) stimulation on gait and postural instability in Parkinson's disease (PD), we compared gait kinematic parameters and preparatory postural adjustments before and 3 months after stimulation in off- and on-drug conditions for seven patients. Gait kinematic parameters and displacements of centre of pressure (CP) and shoulder computed before a lateral raising task of the leg, were recorded using optoelectric Vicon system. Levodopa (L-dopa) induced a clear benefit for gait velocity (related to an increase of stride length) and also an increase of swing phase duration. GPi stimulation had a limited effect, since the increase of gait velocity was induced by a concomitant increase of stride length and cadence corresponding to a compensatory mechanism. The benefit on swing phase duration was also moderate. Displacements of CP were improved mainly by L-dopa. GPi stimulation and L-dopa had the same beneficial effect on the speed at which the CP was transferred back towards the support side, the ankle velocity, the onset time for ankle displacement, and the decrease of shoulder amplitude towards the support side, which reflects a better postural adjustment phase. This study, based on an objective method, revealed that chronic bilateral GPi stimulation may improve gait and preparatory postural adjustments in severe PD patients with a more limited effect than L-dopa.     

Cancer incidence among Parkinson's disease patients in a 10-yrs time-window around disease onset: A large-scale cohort study

ObjectiveTo compare the incidences of any cancer and specific types among patients with Parkinson's disease (PD) in a 10-yrs time window around diagnosis, to that of the general population.MethodsWe conducted a population-based, retrospective large-scale cohort study on 7125 newly diagnosed PD patients who had just initiated anti-parkinsonian medications between 1.1.2000 and 12.31.2012; all members of Maccabi Health Services (MHS), a large Israeli HMO. Cancer incidence during the same period was collected from MHS cancer-registry. Standardized-Incidence-Ratio (SIR) accounting for age, chronological-year and sex were calculated to compare cancer risks of PD patients to that of MHS population.ResultsThe PD cohort (54% males) had a mean age at initiation of anti-parkinsonian medications of 71.2 ± 10.3years. In a time-window of 6.6 ± 3.4years before and 4.0 ± 3.9years after PD was first treated, 21% of the men and 15% of the women were diagnosed with incident-cancer. We found no-difference in any cancer risk for the PD cohort compared to the reference population: SIR = 0.99 (95%CI: 0.92–1.06) for males and 0.98 (95%CI: 0.89–1.07) for females. Risks for lung and colon cancers in the PD cohort were significantly lower for both sexes compared to the reference population. Risks for breast, central nervous system, kidney, leukemia, lymphoma, melanoma, ovarian, pancreatic, prostatic, rectal and thyroid were similar for the two populations. The SIRs did not differ between the sexes.ConclusionsWe found no difference in the risk of any-type of cancer among PD patients compared to the general population, focusing on 10yrs time-window around the initiation of anti-parkinsonian medications.     

Levodopa does not change cerebral vasoreactivity in Parkinson's disease

The aim of this work was to study cerebral vasoreactivity to hypercapnia in Parkinson's disease (PD) before and after levodopa administration. The prospective study was conducted in 20 patients presenting with PD, using 3T blood oxygenation level‐dependent (BOLD) functional MRI (fMRI) covering the whole brain. The hypercapnic stimulus was block‐designed using carbogen inhalation, a gas mixture of 7% CO₂ and 93% O₂, before (OFF) and 60 minutes after administration of a suprathreshold (120%) therapeutic L ‐dopa dose (ON). Ten age‐matched controls were enrolled for between‐group comparisons. Analyses were conducted with a random effects model and corrected for multiple comparisons. No adverse reaction to the hypercapnic stimulus was reported. However, 10 patients and 2 controls were excluded because of incomplete protocol realization, inappropriate hypercapnic stimulus, or excessive movements, leaving 10 patients and 8 controls for further analyses. The hypercapnic stimulus increased whole‐brain BOLD signal of 1.48% ± 0.06% (mean ± standard error) in controls, 1.59% ± 0.05% in patients OFF, and 1.62% ± 0.09% in patients ON. Regions of interest analyses showed a signal increase in gray matter of 2.60% ± 0.16% in controls, 2.89% ± 0.21% in patients OFF, and 2.87% ± 0.12% in patients ON. No global or regional significant difference was detected, when comparing patients OFF and ON L ‐dopa, or between patients and controls. Contrary to Alzheimer's disease, the vasoreactivity to hypercapnia was normal in PD before and after L ‐dopa administration, compared to controls. This negative result is an important finding, especially for neuroscientists using fMRI to investigate motricity and cognition, discarding a significant confounding effect. © 2012 Movement Disorder Society     

Increased levels of 5‐HT1A receptor binding in ventral visual pathways in Parkinson's disease

Visual hallucinations are common in advanced Parkinson's disease (PD). The pathophysiology of visual hallucinations may involve enhanced serotonergic neurotransmission. The atypical antipsychotics clozapine and quetiapine, which have affinity for 5‐HT_2A and 5‐HT_1A receptors, are effective against visual hallucinations in PD. 5‐HT_2A receptors are increased in ventral visual pathways in PD patients with visual hallucinations, and we hypothesized that 5‐HT_1A receptors were also involved in visual hallucinations in PD. Autoradiographic binding using [³H]‐WAY‐100,635 and NAN‐190 was performed in brain sections from 6 PD patients with visual hallucinations, 6 PD patients without visual hallucinations, and 5 age‐matched controls. All PD subjects had been treated with L ‐dopa. Brain areas studied were the orbitofrontal, inferolateral temporal, and motor cortices, as well as the striatum, globus pallidus, substantia nigra, and thalamus. 5‐HT_1A‐binding levels were dramatically increased in the ventral visual pathways of all PD patients compared with controls (0 vs 11 and 0 vs 100 nmol/mg, respectively; both P < .05). There was no significant difference in 5‐HT_1A‐binding levels in PD patients with visual hallucinations compared with PD patients without visual hallucinations or with controls in any of the brain areas studied (P > .05). Gross abnormalities in 5‐HT_1A levels in ventral visual areas occurred in all PD patients exposed to L ‐dopa. However, as there was no difference in 5‐HT_1A‐binding levels between hallucinators and nonhallucinators, alterations in 5‐HT_1A receptor levels may not contribute specifically to visual hallucinations in PD. However, the discrete anatomical distribution of rises to the ventral visual areas suggests some role in predisposing to visual hallucinations. © 2012 Movement Disorder Society     

Pharmacological Therapy in Parkinson's Disease: Focus on Neuroprotection

Although the number of available therapeutic approaches in Parkinson's disease (PD) is steadily increasing the search for effective neuroprotective agent is continuing. Such research is directed at influencing the key steps in the pathomechanism: the mitochondrial dysfunction, the oxidative stress, the neuroinflammatory processes and the final common apoptotic pathway. Earlier‐developed symptomatic therapies were implicated to be neuroprotective, and promising novel disease modifying approaches were brought into the focus of interest. The current review presents a survey of our current knowledge relating to the pathomechanism of PD and discusses the putative neuroprotective therapy.     

Systematic review of incidence studies of Parkinson's disease.

Incidence studies of Parkinson's disease (PD) are important for both health-care planning and epidemiological research. This report reviews the methods and results of previous incidence studies of PD and makes recommendations for future studies. Original articles that described the incidence of PD were located using several strategies. The methods were summarised, and the results of studies with similar methodologies were compared on a standardised population. Twenty-five incidence studies were included. Each used different methods to identify incident patients, although most screened both primary care and hospital records. Only eight studies were prospective, and only two of these had any follow-up. The diagnostic criteria for PD varied (11 studies used two or more cardinal motor features, four used the UK Brain Bank criteria), as did the exclusion criteria and the definition of an incident case. In 16 studies, attempts were made to confirm the diagnosis by examination of patients by a specialist as part of the study. None of the studies used identical methods, but five were sufficiently similar to merit comparison. Four of these gave a similar incidence (16-19/100000/year), but one from Italy had a much lower incidence (8.4/100000), the reason for which was unclear. Five studies found significantly greater incidence in men. This review highlights the difficulties in performing good quality incidence studies of PD. Further incidence studies using standardised methods are required. A set of minimal scientific criteria has been devised to improve the quality and consistency of future studies.     

A trial of buspirone for anxiety in Parkinson's disease: Safety and tolerability

IntroductionIn Parkinson's disease (PD), anxiety is common, associated with lower health-related quality of life, and undertreated. The primary objective of this study was to determine the tolerability of buspirone for the treatment of anxiety in PD.MethodsIndividuals with PD and clinically significant anxiety were randomized 4:1 to flexible dosage buspirone or placebo for 12 weeks. Treatment was initiated at 7.5 mg twice daily and titrated based on response and tolerability to an optimal dosage (maximum 30 mg twice daily). The primary outcome was the proportion of participants who failed to complete the study on study drug. Secondary outcomes included adverse events, dosage reductions, motor function, dyskinesias, and anxiety.ResultsA total of 21 participants enrolled, 4 were randomized to placebo and 17 to buspirone (mean (SD) age 65.5 (9.8), 76.5% male, 88% on concomitant antidepressant or anxiolytic). In the buspirone group, 7 (41%) failed to complete the study on drug, 5 due to intolerability. The median buspirone dosage was 7.5 mg twice daily. No serious adverse events occurred. A total of 9 (53%) buspirone participants experienced adverse events consistent with worsened motor function. In the buspirone group, mean (SD) improvement from baseline to week 12 in Hamilton Anxiety Rating Scale was −3.9 (3.8) and Parkinson Anxiety Scale −7.1 (6.4).ConclusionTolerability concerns do not support moving immediately forward with a large-scale efficacy trial. However, concomitant anxiolytics may have affected tolerability and a signal of efficacy was seen suggesting that future studies of buspirone monotherapy be considered.     

Are high doses of carbidopa a concern? A randomized,clinical trial in Parkinson's disease

Recommended doses of carbidopa are 75‐200 mg/day. Higher doses could inhibit brain aromatic amino‐acid decarboxylase and reduce clinical effects. We compared 4‐week outpatient treatments with carbidopa (75 and 450 mg/day) administered with L ‐dopa on the subjects' normal schedule. After each treatment phase, subjects had two 2‐hour L ‐dopa infusions. The first infusion examined the effects of carbidopa doses administered the preceding 4 weeks, and the second infusion determined the acute effects of the two dosages of carbidopa. The antiparkinsonian effects and L ‐dopa and carbidopa plasma concentrations were monitored during the infusions. Twelve subjects completed the study. Carbidopa concentrations were eight times higher after the high‐carbidopa phase. Area under the curve (AUC) for clinical ratings did not differ for the four L ‐dopa infusions, although AUC for plasma L ‐dopa was modestly increased with 450 mg of carbidopa. Nine subjects reported that the high‐carbidopa outpatient phase was associated with greater response to L ‐dopa. Doses of 450 mg/day of carbidopa did not reduce the responses to L ‐dopa infusion, extending the safe range of carbidopa to 450 mg/day. © 2012 Movement Disorder Society     

l‐Dopa responsiveness is associated with distinctive connectivity patterns in advanced Parkinson's disease

Background : Neuronal loss and dopamine depletion alter motor signal processing between cortical motor areas, basal ganglia, and the thalamus, resulting in the motor manifestations of Parkinson's disease. Dopamine replacement therapy can reverse these manifestations with varying degrees of improvement. Methods : To evaluate functional connectivity in patients with advanced Parkinson's disease and changes in functional connectivity in relation to the degree of response to l ‐dopa, 19 patients with advanced Parkinson's disease underwent resting‐state functional magnetic resonance imaging in the on‐medication state. Scans were obtained on a 3‐Tesla scanner in 3 × 3 × 2.5 mm³ voxels. Seed‐based bivariate regression analyses were carried out with atlas‐defined basal ganglia regions as seeds, to explore relationships between functional connectivity and improvement in the motor section of the UPDRS‐III following an l ‐dopa challenge. False discovery rate‐corrected P was set at < 0.05 for a 2‐tailed t test. Results : A greater improvement in UPDRS‐III scores following l ‐dopa administration was characterized by higher resting‐state functional connectivity between the prefrontal cortex and the striatum (P = 0.001) and lower resting‐state functional connectivity between the pallidum (P = 0.001), subthalamic nucleus (P = 0.003), and the paracentral lobule (supplementary motor area, mesial primary motor, and primary sensory areas). Conclusions : Our findings show characteristic basal ganglia resting‐state functional connectivity patterns associated with different degrees of l‐ dopa responsiveness in patients with advanced Parkinson's disease. l‐ Dopa exerts a graduated influence on remapping connectivity in distinct motor control networks, potentially explaining some of the variance in treatment response. © 2017 International Parkinson and Movement Disorder Society     

Comorbid cancer in Parkinson's disease

The aim of this article was to evaluate cancer occurrence before and after diagnosis of Parkinson's disease (PD). We investigated 692 patients newly diagnosed with PD and 761 age‐ and sex‐matched control subjects identified during two periods (1994–1995 and 2000–2003) within Kaiser Permanente Medical Care Program of Northern California. Primary cancers were searched and dated, and all participants were followed up until the end of membership, death, or December 31, 2008. We used unconditional logistic regression to evaluate the PD–cancer association before the date of PD diagnosis or the index date and Cox proportional hazards regression to evaluate the PD–cancer association after the index date. Nearly 20% (140 of 692) of the PD patients and 25% (188 of 761) of the non‐PD controls had ever had a cancer diagnosis. Before the index date, the prevalence of cancer was not significantly lower in patients with PD (8.1% PD vs. 9.2% controls; OR = 0.83; 95% CI 0.54–1.3). After the index date, the risk of developing a cancer did not differ between PD cases and controls (relative risk [RR] = 0.94; 95% CI 0.70–1.3). Among specific cancers, melanoma was more common among PD cases (before PD, OR = 1.5; 95% CI 0.40–5.2; after PD, RR = 1.6; 95% CI 0.71–3.6), but independent of dopaminergic therapy. Cancer occurrence is not significantly lower among patients with PD. The positive association between PD and subsequent melanoma merits further investigation, as it does not seem to be attributable to dopaminergic therapy, pigmentation, or confounding by smoking. © 2010 Movement Disorder Society.     

Cognitive profile of Parkinson's disease patients: a comparative study between early-onset and late-onset Parkinson's disease

Aim: To investigate the influence of onset age on the occurrence and progression of cognitive dysfunction using neuropsychological tests and the electrophysiological component P300 in both early-onset Parkinson's disease (EOPD) and late-onset Parkinson's disease (LOPD) patients. Methods: A cohort of 76 EOPD patients and 166 LOPD patients was recruited for this study. Demographic information and clinical features, including age, disease duration, education level, family history, the Unified Parkinson's Disease Rating Scale, the Hoehn and Yahr stage, and depression scores were documented for each patient. The Mini-Mental State Examination, Montreal Cognitive Assessment (MoCA), Wechsler Adult Intelligence Scale – Revised, Chinese version (WAIS-RC) and Wechsler Memory Scale – Revised, Chinese version (WMS-RC) were used. In addition, P300 was also examined to assess cognitive function. Results: Although EOPD patients had longer disease duration, their cognitive dysfunction progressed more slowly. The MoCA tests revealed that EOPD patients had higher scores in visuospatial function, attention, delayed recall, and orientation than the LOPD patients. The difference between the two groups on the WMS-RC test did not reach significance, whereas the scores in executive function, visuospatial function and attention as measured on the WAIS-RC test were significantly lower in the LOPD group. In addition, P300 latencies were markedly delayed and P300 amplitudes were reduced in the LOPD group. Conclusions: The current findings demonstrated that cognitive dysfunction progressed more slowly in the EOPD group. Although the LOPD patients exhibited shorter disease durations, their cognitive abilities, including executive function, visuospatial function and attention, may have been impaired.     

Applause sign in advanced Parkinson's disease

BackgroundThe ‘applause sign’ a tendency to continue applauding in response to instructions to clap three times was described in 1995 and was considered specific to degenerative disease, especially to atypical parkinsonian disorders. In early phase Parkinson's disease (PD) the sign has been reported positive as well. In late stage PD it is unknown whether and to what extent the sign may be elicited and it remains unknown if and to what degree the sign correlates to cognitive impairment and PD related dementia.MethodsNursing home residents with PD (MMSE >17) were included. All patients underwent the clapping test and were tested for cognitive disturbance by making use of accepted clinimetrics (MMSE and Scopa-cog). T-testing was performed with the hypothesis that patients expressing the applause sign would score lower on the MMSE or Scopa-cog.ResultsSeventy three nursing home residents (mainly Hoehn and Yahr 4/5) with a mean disease duration of 10 years and a mean age of 78.7 years were included. The applause sign was found positive in 15 of 73 residents (20.5%). Residents expressing the applause sign had significantly lower mean scores on the MMSE (25.1 vs 22.9 points, p < 0.006) and Scopa-cog (14.8 vs 12.0 points, p < 0.039).ConclusionsThe applause sign is present in late stage PD and correlates with a higher degree of cognitive impairment as established with accepted clinimetric tests. A higher degree of frontal lobe involvement explains the presence of the applause sign.