First comprehensive tool for screening pain in Parkinson's disease: the King's Parkinson's Disease Pain Questionnaire.

BACKGROUND AND PURPOSE: Pain is highly prevalent in Parkinson's disease (PD), impacting patients' ability, mood and quality of life. Detecting the presence of pain in its multiple modalities is necessary for adequate personalized management of PD. A 14-item, PD-specific, patient-based questionnaire (the King's Parkinson's Disease Pain Questionnaire, KPPQ) was designed corresponding to the rater-based KPP Scale (KPPS). The present multicentre study was aimed at testing the validity of this screening tool. METHODS: First, a comparison between the KPPQ scores of patients and matched controls was performed. Next, convergent validity, reproducibility (test-retest) and diagnostic performance of the questionnaire were analysed. RESULTS: Data from 300 patients and 150 controls are reported. PD patients declared significantly more pain symptoms than controls (3.96 ± 2.56 vs. 2.17 ± 1.39; P < 0.0001). The KPPQ convergent validity was high with KPPS total score (rS  = 0.80) but weak or moderate with other pain assessments. Test-retest reliability was satisfactory with kappa values ≥0.65 except for item 5, Dyskinetic pains (κ = 0.44), and the intraclass correlation coefficient (ICC) for the KPPQ total score was 0.98. After the scores of the KPPS were adapted for screening (0, no symptom; ≥1, symptom present), a good agreement was found between the KPPQ and the KPPS (ICC = 0.88). A strong correlation (rS  = 0.80) between the two instruments was found. The diagnostic parameters of the KPPQ were very satisfactory as a whole, with a global accuracy of 78.3%-98.3%. CONCLUSIONS: These results suggest that the KPPQ is a useful, reliable and valid screening instrument for pain in PD to advance patient-related outcomes.

Pain in Parkinson's disease: facts and uncertainties.

Pain is one of the most common and troublesome non-motor symptoms of Parkinson's disease (PD). It can appear at any time during the disease and is often present before diagnosis. However, there is little or no consensus on its definition. An expert group of clinicians with relevant research experience met to review the existing evidence and to identify gaps in our understanding leading towards AUTHOR: 'understanding towards' has been changed to 'understanding leading towards'. Please check and confirm that this is appropriate an optimized therapy of pain in PD. Key findings from epidemiologic, neurophysiologic, neuroimaging and clinical studies are reviewed. In each case, the evidence base is limited by wide variations in the definitions of pain applied, study methodologies and populations evaluated. Disease-related and medical conditions trigger spontaneous pain in patients with PD, which is then abnormally processed and results in painful manifestations in specific body parts. Dopaminergic medications, such as rotigotine, as well as opiate analgesics, such as oxycodone, have shown positive results but future studies with more detailed pain characterization at inclusion are warranted.

The Parkinson's Disease Composite Scale: results of the first validation study.

BACKGROUND AND PURPOSE: The aim was to validate the Parkinson's Disease Composite Scale (PDCS). METHODS: The study included 194 Parkinson's disease (PD) patients in five countries. Investigators completed the following scales: PDCS, the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Parkinson's Disease Sleep Scale Version 2, Montreal Cognitive Assessment, the Scale for Evaluation of Neuropsychiatric Disorders in Parkinson's Disease and the Clinical Impression of Severity Index for PD (CISI-PD). For test-retest analysis, a second administration of the PDCS was carried out in 61 stable patients (as per the CISI-PD) in 7-14 days after the first evaluation. The PDCS is a novel scale for PD with a total of 17 items divided into four domains: motor, non-motor, treatment complications and disability. RESULTS: Parkinson's Disease Composite Scale mean and median values were close. Skewness values were into the criterion limits (-1 to +1). The complete range of scores was covered for 14 of the 17 items (83.4%). A floor effect of 25.26% and 28.25% was observed in the complications and disability level dimensions due to the proportion of patients free of these difficulties. No relevant floor or ceiling effect was observed for the PDCS total score (1.03% and 0.52%, respectively). The stability of the scale appeared excellent with most items meeting weighted kappa and intraclass correlation coefficient values >0.80. The convergent validity of the PDCS with corresponding scores of the MDS-UPDRS showed high correlation values (rS  ≥ 0.60). The internal validity was into acceptable limits, with the majority of values higher than the minimal 0.30 threshold. The standard error of measurement suggested a satisfactory precision (SEM 3.81, <30% of the PDCS total score standard deviation). CONCLUSION: The PDCS appears to be a feasible, acceptable, reproducible and valid scale.

Constipation is not associated with dopamine transporter pathology in early drug-naïve patients with Parkinson's disease.

BACKGROUND AND PURPOSE: Constipation is a common non-motor symptom of Parkinson's disease (PD). Deposition of α-synuclein inclusions that spread from the gut to the substantia nigra through the vagus nerve has recently been speculated to be a pre-motor and early stage of PD. The aim of the study was to investigate whether constipation is associated with dopaminergic pathology on dopamine transporter (DAT) single-photon emission computed tomography in early drug-naïve patients with PD. Our hypothesis was that constipation is associated with other signs of pre-motor PD and is independent of DAT pathology. We then investigated for associations with motor and non-motor symptoms, and with cerebrospinal fluid biomarkers of PD pathology. METHODS: Using the Parkinson's Progression Markers Initiative database, we investigated the prevalence of constipation and the association between constipation and clinical features, striatal [123 I]Ioflupane uptake and non-imaging (cerebrospinal fluid and serum) biomarkers. Constipation was evaluated using Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part I item 1.11. RESULTS: One third (132/398) of de-novo patients with PD had constipation. Higher severity of constipation correlated with older age (r = 0.728, P < 0.001), higher MDS-UPDRS total score (r = 0.285, P < 0.001), worse postural instability (r = 0.190, P = 0.012), rapid eye movement sleep behaviour disorder (r = 0.228, P < 0.0001) and depression (r = 0.187, P = 0.024). No correlation was found with cerebrospinal fluid, serum and imaging markers of PD pathology. CONCLUSIONS: Constipation was not associated with DAT pathology but with rapid eye movement sleep behaviour disorder and depression, which are speculated to be pre-motor symptoms of PD. This confirms the hypothesis that constipation may be a pre-motor sign of PD due to an impairment of non-dopaminergic pathways.

The cost-effectiveness of levodopa/carbidopa intestinal gel compared to standard care in advanced Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is an incurable, progressive neurological condition, with symptoms impacting movement, walking, and posture that eventually become severely disabling. Advanced PD (aPD) has a significant impact on quality-of-life (QoL) for patients and their caregivers/families. Levodopa/carbidopa intestinal gel (LCIG) is indicated for the treatment of advanced levodopa-responsive PD with severe motor fluctuations and hyper-/dyskinesia when available combinations of therapy have not given satisfactory results. AIMS: To determine the cost-effectiveness of LCIG vs standard of care (SoC) for the treatment of aPD patients. METHODS: A Markov model was used to evaluate LCIG vs SoC in a hypothetical cohort of 100 aPD patients with severe motor fluctuations from an Irish healthcare perspective. Model health states were defined by Hoehn & Yahr (H&Y) scale-combined with amount of time in OFF-time-and death. SoC comprised of standard oral therapy ± subcutaneous apomorphine infusion and standard follow-up visits. Clinical efficacy, utilities, and transition probabilities were derived from published studies. Resource use was estimated from individual patient-level data from Adelphi 2012 UK dataset, using Irish costs, where possible. Time horizon was 20 years. Costs and outcomes were discounted at 4%. Both one-way and probabilistic sensitivity analyses were conducted. RESULTS: The incremental cost-effectiveness ratio for LCIG vs SOC was €26,944/quality adjusted life year (QALY) (total costs and QALYs for LCIG vs SoC: €537,687 vs €514,037 and 4.37 vs 3.49, respectively). LCIG is cost-effective at a payer threshold of €45,000. The model was most sensitive to health state costs. CONCLUSION: LCIG is a cost-effective treatment option compared with SoC in patients with aPD.

Impulse control disorder related behaviours during long-term rotigotine treatment: a post hoc analysis.

BACKGROUND AND PURPOSE: Dopamine agonists in Parkinson's disease (PD) are associated with impulse control disorders (ICDs) and other compulsive behaviours (together called ICD behaviours). The frequency of ICD behaviours reported as adverse events (AEs) in long-term studies of rotigotine transdermal patch in PD was evaluated. METHODS: This was a post hoc analysis of six open-label extension studies up to 6 years in duration. Analyses included patients treated with rotigotine for at least 6 months and administered the modified Minnesota Impulse Disorders Interview. ICD behaviours reported as AEs were identified and categorized. RESULTS: For 786 patients, the mean (±SD) exposure to rotigotine was 49.4 ± 17.6 months. 71 (9.0%) patients reported 106 ICD AEs cumulatively. Occurrence was similar across categories: 2.5% patients reported 'compulsive sexual behaviour', 2.3% 'buying disorder', 2.0% 'compulsive gambling', 1.7% 'compulsive eating' and 1.7% 'punding behaviour'. Examining at 6-month intervals, the incidence was relatively low during the first 30 months; it was higher over the next 30 months, peaking in the 54-60-month period. No ICD AEs were serious, and 97% were mild or moderate in intensity. Study discontinuation occurred in seven (9.9%) patients with ICD AEs; these then resolved in five patients. Dose reduction occurred for 23 AEs, with the majority (73.9%) resolving. CONCLUSIONS: In this analysis of >750 patients with PD treated with rotigotine, the frequency of ICD behaviour AEs was 9.0%, with a specific incidence timeline observed. Active surveillance as duration of treatment increases may help early identification and management; once ICD behaviours are present rotigotine dose reduction may be considered.

Night-time sleep in Parkinson's disease - the potential use of Parkinson's KinetiGraph: a prospective comparative study.

BACKGROUND AND PURPOSE: Night-time sleep disturbances are important non-motor symptoms and key determinants of health-related quality of life (HRQoL) in patients with Parkinson's disease (PD). The Parkinson's KinetiGraph (PKG) can be used as an objective measure of different motor states and periods of immobility may reflect episodes of sleep. Our aim was to evaluate whether PKG can be used as an objective marker of disturbed night-time sleep in PD. METHODS: In this prospective comparative study, data from PKG recordings over six consecutive 24 h periods are compared with Hauser diaries and scales focusing on motor state, sleep and HRQoL in PD patients. Thirty-three 'non-sleepy' PD patients (PD-NS) were compared with 30 PD patients presenting with excessive daytime sleepiness (PD-EDS). The groups were matched for age, gender and Hoehn and Yahr state. RESULTS: In the PD-EDS group subjective sleep reports correlated with the PKG's parameters for quantity and quality night-time sleep, but not in the PD-NS group. There were no significant correlations of the night-time sleep quantity parameters of the Hauser diary with subjective sleep perception, neither in the PD-EDS nor in the PD-NS group. CONCLUSIONS: This first PKG based study of night-time sleep in PD suggests that PKG could be used to provide an easy to use and rough evaluation of aspects of night-time sleep and one that could flag patients where polysomnography may be required. In sleepy PD patients for instance, quantity and quality PKG parameters correlate with different aspects of sleep such as insomnia, parasomnia and restless legs syndrome.

Assessing the non-motor symptoms of Parkinson's disease: MDS-UPDRS and NMS Scale.

BACKGROUND AND PURPOSE: Although Parkinson's disease (PD) is characterized by typical motor manifestations, non-motor symptoms (NMS) are an outstanding part of the disease. At present, several specific instruments for assessment of NMS are available. The objective of our study was to determine the performance of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Part I - Non-Motor Aspects of Experiences of Daily Living (nM-EDL) compared with the Non-Motor Symptoms Scale (NMSS). METHODS: To this purpose, 434 consecutive patients with PD were included in an international, observational, cross-sectional study. The association between scores of both scales was determined by the Spearman rank correlation coefficient. Equations for transformation of total score of a scale to the other were constructed from weighted regression models and both, transformed and observed score, contrasted by means of the Lin's Concordance Correlation Coefficient (LCCC) and Bland-Altman plot. RESULTS: As a whole, the prevalence of the NMS according to each scale was quite similar, and most of the correlations between their corresponding components were high (r(S) > 0.60). The total score correlation of the MDS-UPDRS Part I with the NMSS was high (r(S) = 0.81). Concerning the transformed scores, estimated scores only partially approach the observed ones (sharing about 60-64% of the variance) because residual variance increased with increasing magnitudes of the scores, i.e. the most severe patients (Bland-Altman plot; LCCC < 0.60 for severe patients). CONCLUSIONS: (i) MDS-UPDRS Part I (nM-EDL) and NMSS showed a strong convergent validity; (ii) however, transformed scores using the equations from weighted regression models showed that for patients with the most severe NMS they are not concordant.

Practice Parameter: treatment of nonmotor symptoms of Parkinson disease: report of the Quality Standards Subcommittee of the American Academy of Neurology.

OBJECTIVE: Nonmotor symptoms (sleep dysfunction, sensory symptoms, autonomic dysfunction, mood disorders, and cognitive abnormalities) in Parkinson disease (PD) are a major cause of morbidity, yet are often underrecognized. This evidence-based practice parameter evaluates treatment options for the nonmotor symptoms of PD. Articles pertaining to cognitive and mood dysfunction in PD, as well as treatment of sialorrhea with botulinum toxin, were previously reviewed as part of American Academy of Neurology practice parameters and were not included here. METHODS: A literature search of MEDLINE, EMBASE, and Science Citation Index was performed to identify clinical trials in patients with nonmotor symptoms of PD published between 1966 and August 2008. Articles were classified according to a 4-tiered level of evidence scheme and recommendations were based on the level of evidence. RESULTS AND RECOMMENDATIONS: Sildenafil citrate (50 mg) may be considered to treat erectile dysfunction in patients with Parkinson disease (PD) (Level C). Macrogol (polyethylene glycol) may be considered to treat constipation in patients with PD (Level C). The use of levodopa/carbidopa probably decreases the frequency of spontaneous nighttime leg movements, and should be considered to treat periodic limb movements of sleep in patients with PD (Level B). There is insufficient evidence to support or refute specific treatments for urinary incontinence, orthostatic hypotension, and anxiety (Level U). Future research should include concerted and interdisciplinary efforts toward finding treatments for nonmotor symptoms of PD.

International study on the psychometric attributes of the non-motor symptoms scale in Parkinson disease.

BACKGROUND: Nonmotor symptoms (NMS) have a great impact on patients with Parkinson disease (PD). The Non-Motor Symptoms Scale (NMSS) is an instrument specifically designed for the comprehensive assessment of NMS in patients with PD. NMSS psychometric properties have been tested in this study. METHODS: Data were collected in 12 centers across 10 countries in America, Asia, and Europe. In addition to the NMSS, the following measures were applied: Scales for Outcomes in Parkinson's Disease (SCOPA)-Motor, SCOPA-Psychiatric Complications (SCOPA-PC), SCOPA-Cognition, Hoehn and Yahr Staging (HY), Clinical Impression of Severity Index for Parkinson's Disease (CISI-PD), SCOPA-Autonomic, Parkinson's Disease Sleep Scale (PDSS), Parkinson's Disease Questionnaire-39 items (PDQ-39), and EuroQol-5 dimensions (EQ-5D). NMSS acceptability, reliability, validity, and precision were analyzed. RESULTS: Four hundred eleven patients with PD, 61.3% men, were recruited. The mean age was 64.5 +/- 9.9 years, and mean disease duration was 8.1 +/- 5.7 years. The NMSS score was 57.1 +/- 44.0 points. The scale was free of floor or ceiling effects. For domains, the Cronbach alpha coefficient ranged from 0.44 to 0.85. The intraclass correlation coefficient (0.90 for the total score, 0.67-0.91 for domains) and Lin concordance coefficient (0.88) suggested satisfactory reproducibility. The NMSS total score correlated significantly with SCOPA-Autonomic, PDQ-39, and EQ-5D (r(S) = 0.57-0.70). Association was close between NMSS domains and the corresponding SCOPA-Autonomic domains (r(S) = 0.51-0.65) and also with scales measuring related constructs (PDSS, SCOPA-PC) (all p < 0.0001). The NMSS total score was higher for women (p < 0.02) and for increasing disease duration, HY, and CISI-PD severity level (p < 0.001). The SEM was 13.91 for total score and 1.71 to 4.73 for domains. CONCLUSION: The Non-Motor Symptoms Scale is an acceptable, reproducible, valid, and precise assessment instrument for nonmotor symptoms in Parkinson disease.

Clinical risk-benefit assessment of dopamine agonists.

Dopamine agonists (DAs) have proven efficacy as monotherapy in early Parkinson's disease (PD) for preventing motor complications such as dyskinesia and as adjunct therapy as the disease progresses. Further, it is increasingly evident that at least some DAs may provide additional benefits, such as reduction in depressive symptoms and treatment of refractory tremor. Different side-effect profiles have been associated with levodopa and ergot or non-ergot DA treatment, such as sudden onset of sleep, reduced impulse control, hallucination, and cardiovascular fibrosis. This paper discusses the evidence for specific associations between particular treatments and side effects as well as the clinical implications for patient care. Ultimately, the choice depends on the risk-benefit assessment as it applies to the individual patient's clinical profile and the physician's preference.

Long-term clinical and positron emission tomography outcome of fetal striatal transplantation in Huntington's disease.

Two patients with moderate Huntington's disease (HD) received bilateral fetal striatal allografts. One patient demonstrated, for the first time, increased striatal D2 receptor binding, evident with 11C-raclopride positron emission tomography, and prolonged clinical improvement over 5 years, suggesting long term survival and efficacy of the graft. The other patient did not improve clinically or radiologically. Our results indicate that striatal transplantation in HD may be beneficial but further studies are needed to confirm this.

Nature and variants of idiopathic restless legs syndrome: observations from 152 patients referred to secondary care in the UK.

BACKGROUND: Heterogeneity in clinical presentation and daytime somnolence in restless legs syndrome (RLS) have been poorly explored in the UK. MATERIAL AND METHODS: Analysis of database of 152 cases of primary RLS compiled from clinical consultation using a structured questionnaire administration and clinical examination, spanning six years of referral. Standard evaluations included use of the Epworth Sleepiness Scale (ESS). Secondary RLS was excluded and polysomnography performed in some when clinically indicated. RESULTS: The mean duration of RLS before appropriate treatment initiation was 12.7 years (age range of patients 26-90 years). 79% of patients had insomnia while 30% had excessive daytime sleepiness (EDS). Severe pain, restless arms and paroxysmal RLS causing lifestyle alterations also occurred. CONCLUSIONS: This study suggests that there is considerable delay before appropriate therapy in RLS. A large number have EDS and insomnia among others, is the commonest presenting feature. Phenotypic heterogeneity may cause diagnostic difficulty.

Measuring brain stem and cerebellar damage in parkinsonian syndromes using diffusion tensor MRI.

OBJECTIVE: To use diffusion tensor MRI to quantify and compare degeneration of the pons and cerebellar peduncles in multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and Parkinson disease (PD) and to relate changes in diffusion measures to clinical features and localized atrophy. METHODS: We used a region-of-interest approach to measure changes in fractional anisotropy and mean diffusivity in the middle cerebellar peduncles, decussation of the superior cerebellar peduncles, and pons in 17 patients with MSA, 17 with PSP, 12 with PD, and 12 healthy volunteers. We also evaluated atrophy of the cerebellar peduncles and pons on T2-weighted magnetic resonance images in patients with MSA and PSP. RESULTS: In MSA, fractional anisotropy was markedly reduced in the middle cerebellar peduncles, and mean diffusivity increased both here and in the pons compared with other groups, whereas in PSP, mean diffusivity was strikingly increased in the decussation of superior cerebellar peduncles. Cerebellar ataxia was related to mean diffusivity in the middle cerebellar peduncles (r = 0.71, p = 0.001) and pons (r = 0.60, p = 0.01) in MSA. Diffusion measures were related to localized atrophy in both MSA and PSP. CONCLUSIONS: Diffusion tensor MRI can be used to quantify neurodegenerative processes in different brain stem and cerebellar structures in multiple system atrophy and progressive supranuclear palsy during life, and may have diagnostic value. Larger studies of early, undifferentiated parkinsonian syndromes are indicated to provide estimates of the relative diagnostic value of diffusion measures, atrophy measures, and visual assessment of scans.

Genetic aspects of restless legs syndrome.

Restless legs syndrome (RLS), also known as Ekbom syndrome, is a common movement disorder with sensorimotor symptoms occurring during sleep and quiet wakefulness. The underlying cause for RLS is unknown but genetic influences play a strong part in the pathogenesis of RLS, particularly when the condition starts at a young age. This review explores the genetic basis of RLS and related phenotypic variations. Recently, three loci showing vulnerability to RLS have been described in French-Canadian and Italian families in chromosomes 12q, 14q and 9q, emphasising on an autosomal dominant mode of inheritance. These have been labelled RLS1, RLS2 and RLS3, respectively. However, specific causative mutations remain elusive and no linkage analysis has been identified so far in the candidate genes investigated in RLS.

Myasthenia gravis--a rare presentation with tongue atrophy and fasciculation.

We report the case of an unusual presentation of myasthenia gravis with tongue atrophy and fasciculation. Myasthenia gravis is an autoimmune condition associated with weakness and fatigability of voluntary muscles. In >50%, the initial symptoms and signs are related to extraocular muscle weakness, such as diplopia or ptosis [Tsung K, Seggev JS. An unusual cause of dysphagia. West J Med 1995; 163: 159-60]. Rarely, it is known to affect bulbar muscles and can lead to dysphagia and respiratory compromise.

The Parkinson's disease sleep scale: a new instrument for assessing sleep and nocturnal disability in Parkinson's disease.

BACKGROUND: No formal instruments are available for quantifying sleep problems in Parkinson's disease. OBJECTIVE: To develop a new sleep scale to quantify the various aspects of nocturnal sleep problems in Parkinson's disease, which may occur in up to 96% of affected individuals. METHODS: Employing a multidisciplinary team approach, a visual analogue scale was devised addressing 15 commonly reported symptoms associated with sleep disturbance in Parkinson's disease-the Parkinson's disease sleep scale (PDSS). In all, 143 patients with Parkinson's disease completed the PDSS, covering the entire spectrum of disease from newly diagnosed to advanced stage. As controls, 137 age healthy matched subjects also completed the scale. Test-retest reliability was assessed in a subgroup of subjects. The Epworth sleepiness scale was also satisfactorily completed by 103 of the patients with Parkinson's disease. RESULTS: PDSS scores in the Parkinson group were significantly different from the healthy controls. Patients with advanced Parkinson's disease had impaired scores compared with early/moderate disease. Individual items of the scale showed good discriminatory power between Parkinson's disease and healthy controls. Relevant items of the PDSS correlated with excessive daytime sleepiness. The scale showed robust test-retest reliability. CONCLUSIONS: This appears to be the first description of a simple bedside screening instrument for evaluation of sleep disturbances in Parkinson's disease. A combination of subitems may help identify specific aspects of sleep disturbance, which in turn may help target treatment.

A randomised placebo controlled exploratory study of vitamin B-12, lofepramine, and L-phenylalanine (the "Cari Loder regime") in the treatment of multiple sclerosis.

OBJECTIVE: To determine whether combination therapy with lofepramine, L-phenylalanine, and intramuscular vitamin B-12 (the "Cari Loder regime") reduces disability in patients with multiple sclerosis. METHODS: A placebo controlled, double blind, randomised study carried out in five United Kingdom centres on outpatients with clinically definite multiple sclerosis, measurable disability on Guy's neurological disability scale (GNDS), no relapse in the preceding six months, and not on antidepressant drugs. Over 24 weeks all patients received vitamin B-12, 1 mg intramuscularly weekly, and either lofepramine 70 mg and L-phenylalanine 500 mg twice daily, or matching placebo tablets. Outcome was assessed using the GNDS, the Kurtzke expanded disability status scale; the Beck depression inventory, the Chalder fatigue scale, and the Gulick MS specific symptom scale. RESULTS: 138 patients were entered, and two were lost from each group. There was no statistically significant difference between the groups at entry or at follow up. Analysis of covariance suggested that treated patients had better outcomes on four of the five scales used. Both groups showed a reduction of 2 GNDS points within the first two weeks, and when data from all time points were considered, the treated group had a significant improvement of 0.6 GNDS points from two weeks onwards. CONCLUSIONS: Patients with multiple sclerosis improved by 2 GNDS points after starting vitamin B-12 injections. The addition of lofepramine and L-phenylalanine added a further 0.6 points benefit. More research is needed to confirm and explore the significance of this clinically small difference.

Treatment of Parkinson's disease and restless legs syndrome with cabergoline, a long-acting dopamine agonist.

Dopamine agonists have diverse chemical and physical properties that can directly stimulate the dopamine receptors, unlike levodopa which undergoes presynaptic breakdown to dopamine before dopaminergic effects in Parkinson's disease (PD). Cabergoline, a dopamine agonist effective given once daily, is being used as treatment for PD. In theory, therapy with cabergoline provides striatal intrasynaptic dopamine replacement of PD in a physiological manner because of its long half-life and the resultant sustained rather than pulsatile dopaminergic stimulation. Several placebo-controlled trials using cabergoline as adjunctive therapy in PD have shown that cabergoline significantly reduces 'off' time, improves motor function and reduces levodopa requirement. Cabergoline has also been used as monotherapy in PD and has been shown to be as effective as other dopamine agonists in improving motor function and to be superior to levodopa in reducing dyskinesias over a five-year period. Work from our group and others have also demonstrated the efficacy of cabergoline in PD patients with nocturnal disabilities and those with restless legs syndrome (RLS). More recently we have reported that cabergoline is a well-tolerated dopamine agonist in both young and elderly patients and has an acceptable side-effect profile.

A polymorphism in the dopamine receptor DRD5 is associated with blepharospasm.

Abnormalities in dopamine neurotransmission are thought to underlie the generation of dystonic movements. The authors performed a case-control allelic association study in patients with the focal dystonia blepharospasm, using polymorphisms in the dopamine receptor and transporter genes. Allele 2 of a DRD5 dinucleotide repeat was significantly associated with blepharospasm. This may indicate a pathogenic role for this receptor.