The Movement Disorder Society Evidence-Based Medicine Review Update: Treatments for the non-motor symptoms of Parkinson's disease

Palliative care for Parkinson's disease: a summary of the evidence and future directions

BACKGROUND

Parkinson's disease is a common, life-limiting, neurodegenerative condition. Despite calls for improved access to palliative care for people with Parkinson's disease, services have been slow in developing. Obstacles include poor understanding and recognition of palliative care needs, the role for specialist palliative care services and an agreed structure for sustainable palliative care provision.

AIM

To summarise the evidence base for palliative care in Parkinson's disease, linking current understanding with implications for clinical practice and identifying areas for future research.

WHAT IS KNOWN

Convention recognises a final 'palliative phase' in Parkinson's disease, while qualitative studies suggest the presence of palliative care need in Parkinson's disease from diagnosis. Clinical tools to quantify palliative symptom burden exist and have helped to identify targets for intervention. Dementia is highly prevalent and influences many aspects of palliative care in Parkinson's disease, with particular implications for end-of-life care and advance care planning.

IMPLICATIONS FOR CLINICAL PRACTICE

The 'palliative phase' represents a poor entry point for consideration of palliative care need in Parkinson's disease. An alternative, integrated model of care, promoting collaboration between specialist palliative and neurological services, is discussed, along with some specific palliative interventions. WHAT IS UNKNOWN: Limited evidence exists regarding timing of palliative interventions, triggers for specialist referral and management of terminal care.

IMPLICATIONS FOR FUTURE RESEARCH

Research examining access to palliative care and management of terminal symptoms will assist development of sustainable, integrated palliative care services for Parkinson's disease.

A latent class analysis of psychological disturbance in Parkinson's disease

OBJECTIVE

Psychological symptoms are common in Parkinson's disease (PD). Psychological symptoms do not respond to psychotropic medications as well in patients with PD as in patients with psychiatric illnesses who do not have PD. Evidence that PD patients can be classified into distinct psychological symptom subgroups is conflicting. This study sought to examine potential psychological heterogeneity in PD with a broader range of instruments than has been used in previous studies.

METHODS

A comprehensive battery of psychological measures assessing dysphoria, apathy, anhedonia, anxiety, and negative affect was administered to 95 PD patients without global cognitive impairment. Latent class analysis was used to identify subgroups of patients based on continuous variables derived from the psychological battery. Multinomial regression was used to examine predictors of classification.

RESULTS

The latent class analysis identified three subgroups with incremental levels of psychopathology across most symptom domains. One exception was a greater level of affective flattening in the "psychologically healthy" group compared with the "moderate symptoms" group. Greater motor dysfunction and less education were associated with greater severity of psychological symptoms.

CONCLUSIONS

These results support high psychological co-morbidity in PD, which complicates the treatment of individual symptoms. In addition, emotional blunting and anhedonia may be less indicative of widespread psychological distress than anxiety, dysphoria, and cognitive aspects of apathy. Clinicians should be aware that PD patients with greater motor dysfunction and less education are at greater risk not only for depression but also for a variety of other psychological symptoms that may not be routinely assessed.

Quantitative wearable sensors for objective assessment of Parkinson's disease

There is a rapidly growing interest in the quantitative assessment of Parkinson's disease (PD)-associated signs and disability using wearable technology. Both persons with PD and their clinicians see advantages in such developments. Specifically, quantitative assessments using wearable technology may allow for continuous, unobtrusive, objective, and ecologically valid data collection. Also, this approach may improve patient-doctor interaction, influence therapeutic decisions, and ultimately ameliorate patients' global health status. In addition, such measures have the potential to be used as outcome parameters in clinical trials, allowing for frequent assessments; eg, in the home setting. This review discusses promising wearable technology, addresses which parameters should be prioritized in such assessment strategies, and reports about studies that have already investigated daily life issues in PD using this new technology.

New pharmacological options for treating advanced Parkinson's disease

BACKGROUND

Parkinson's disease (PD) affects about 1% of the over 60 population and is characterized by a combination of motor symptoms (rest tremor, bradykinesia, rigidity, postural instability, stooped posture and freezing of gait [FoG]) and non-motor symptoms (including psychiatric and cognitive disorders). Given that the loss of dopamine in the striatum is the main pathochemical hallmark of PD, pharmacological treatment of the disease has focused on restoring dopaminergic neurotransmission and thus improving motor symptoms. However, the currently licensed medications have several major limitations. Firstly, dopaminergic medications modulate all the key steps in dopamine transmission other than the most powerful determinant of extracellular dopamine levels: the activity of the presynaptic dopamine transporter. Secondly, other monoaminergic neurotransmission systems (ie noradrenergic, cholinergic and glutamatergic systems are altered in PD and may be involved in a variety of motor and non-motor symptoms. Thirdly, today's randomized clinical trials are primarily designed to assess the efficacy and safety of treatments for motor fluctuations and dyskinesia. Fourthly, there is a need for disease- modifying treatments (DMTs) that slow disease progression and reduce the occurrence of the very disabling disorders seen in late-stage PD.

OBJECTIVE

To systematically review a number of putative pharmacological options for treating the main impairments in late-stage PD (ie gait disorders, cognitive disorders and behavioural disorders such as apathy).

METHODS

We searched the PubMed database up until July 2013 with logical combinations of the following search terms: "Parkinson's disease", "gait", "cognition", "apathy", "advanced stage", "modulation", "noradrenergic", "cholinergic", "glutamatergic" and "neurotransmission".

RESULTS

In patients undergoing subthalamic nucleus stimulation, the potentiation of noradrenergic and dopaminergic transmission by methylphenidate improves gait and FoG and may relieve apathy. However, the drug failed to improve cognition in this population. Potentiation of the cholinergic system by acetylcholinesterase inhibitors (which are licensed for use in dementia) may reduce pre-dementia apathy and falls. Modulation of the glutamatergic system by an N-methyl-D-aspartate receptor antagonist did not improve gait and dementia but may have reduced axial rigidity. A number of putative DMTs have been reported.

DISCUSSION

Novel therapeutic strategies should seek to reduce the appearance of the very disabling disorders observed in late-stage PD. Dopamine and/or noradrenaline transporter inhibitors, anticholinesterase inhibitors, Peroxisome-proliferator-activated-receptor-agonists and iron chelators should at least be investigated as putative DMTs by applying a delayed-start clinical trial paradigm to a large population

CONCLUSIONS

There is a need for more randomized clinical trials of treatments for late-stage PD.

Initial treatment of Parkinson's disease: an update

OPINION STATEMENT

This is an update to an article published in this journal in 2006, which covered the initial treatment of Parkinson's disease (PD). In this update, we review new research into symptomatic treatments, potential disease modifying ("neuroprotective") agents, and evidence-based reviews of current treatment. We discuss the usage of the MAO-B inhibitors, including the controversy surrounding the possible neuroprotective effects of rasagiline. Usage of extended release formulations of pramipexole and ropinirole, as well as the transdermal dopamine agonist rotigotine, are reviewed. Side effects of the dopamine agonists are discussed, including the cardiac side effects of ergot-derived dopamine agonists, and the impulse control disorders associated with the dopamine agonists. The use of zonisamide as an agent for PD tremor is reviewed. We touch on the clinical research into the benefits of exercise in PD, and briefly review some of the current studies for new formulations of levodopa and other medications and treatments with novel mechanisms of action.

Orthostatic hypotension in Parkinson’s disease

SUMMARY Orthostatic hypotension (OH) is a frequent non-motor symptom in Parkinson’s disease (PD), affecting between 22.9 and 38.4% of patients. In PD, OH is related to an increased risk of falls, and possibly to cognitive dysfunction and increased mortality. These data emphasize the importance of its prompt recognition and treatment. OH is related to pre- and post-ganglionic adrenergic denervation, but other factors, such as drugs, heat, meals or alcohol intake, might also induce or aggravate it. Evidence about the efficacy and safety of pharmacological or nonpharmacological strategies for OH treatment in PD is weak. Nonpharmacological measures include liberal addition of salt to the diet, exercise, compression stockings or physical maneuvers. Severe cases may be treated with midodrine or fludrocortisone. Some results suggest that droxidopa and fipamezole may be effective treatments. We finish this review article by discussing the most important unanswered questions about PD-related OH, which may be the focus of future research.

Parkinson's disease dementia: convergence of α-synuclein, tau and amyloid-β pathologies

Dementia is increasingly being recognized in cases of Parkinson's disease (PD); such cases are termed PD dementia (PDD). The spread of fibrillar α-synuclein (α-syn) pathology from the brainstem to limbic and neocortical structures seems to be the strongest neuropathological correlate of emerging dementia in PD. In addition, up to 50% of patients with PDD also develop sufficient numbers of amyloid-β plaques and tau-containing neurofibrillary tangles for a secondary diagnosis of Alzheimer's disease, and these pathologies may act synergistically with α-syn pathology to confer a worse prognosis. An understanding of the relationships between these three distinct pathologies and their resultant clinical phenotypes is crucial for the development of effective disease-modifying treatments for PD and PDD.

Parkinson’s Disease: Symptoms, Unmet Needs and New Therapeutic Targets

Parkinson’s disease is classically defined by the presence of two or more of the following cardinal motor symptoms: bradykinesia, rigidity, tremor at rest, and gait disturbances. In the past two decades, the non‐motor symptom complex of the disease has gained increasing attention, warranted by the impact it has on patient quality of life. In this introductory chapter, the clinical characterization of the motor and non‐motor symptoms is extensively described and the possible pathophysiological mechanisms underlying each symptom are delineated. Furthermore, the subtypes of Parkinson’s disease, based on empirical and data‐driven systems, are discussed. An updated summary of the current state‐of‐the‐art in diagnosis and treatment is briefly covered. Finally, the currently unmet needs and direction of investigative efforts are analyzed, focusing on the non‐dopamine responsive symptoms and the search for biomarkers, cause‐directed effective treatments and neuroprotective therapies.

Advances in the pharmacological treatment of Parkinson's disease: targeting neurotransmitter systems

For several decades, the dopamine precursor levodopa has been the primary therapy for Parkinson's disease (PD). However, not all of the motor and non-motor features of PD can be attributed solely to dopaminergic dysfunction. Recent clinical and preclinical advances provide a basis for the identification of additional innovative therapeutic options to improve the management of the disease. Novel pharmacological strategies must be optimized for PD by: (i) targeting disturbances of the serotonergic, noradrenergic, glutamatergic, GABAergic, and cholinergic systems in addition to the dopaminergic system, and (ii) characterizing alterations in the levels of neurotransmitter receptors and transporters that are associated with the various manifestations of the disease.

A fixed-dose randomized controlled trial of olanzapine for psychosis in Parkinson disease

Background: Psychosis is a common and debilitating side effect of long-term dopaminergic treatment of Parkinson disease (PD). While clozapine is an effective treatment, the need for blood monitoring has limited its first-line use. 

Objective: Since olanzapine shows similar receptor affinity to clozapine, we hypothesized that it might be an effective alternative to clozapine for treatment of drug-induced psychosis (DIP) in PD, and that lower doses than usual might make it tolerable.

Methods: In 1998-2003 we conducted a four-week, double-blind, placebo-controlled, parallel group, fixed-dose trial of olanzapine (0, 2.5mg, or 5mg) in 23 PD patients with DIP while allowing for clinically realistic dose adjustments of dopaminomimetic mid-study. The primary outcome measures were Brief Psychiatric Rating Scale (BPRS) ratings scored from videotaped interviews after study termination by an observer blinded to dose assignment and to interview timing, and CGI (Clinical Global Impression). The Unified Parkinson’s Disease Rating Scale motor subscale (UPDRS) was the primary measure of tolerability.

Results: Intention-to-treat analysis found no significant differences among treatment groups in study completion or serious adverse events. However, a disproportionate number of olanzapine vs. placebo subjects reported mild side effects (p<0.04), many citing motor worsening. Fourteen patients completed the study (seven on placebo, two on 2.5mg olanzapine, five on 5mg olanzapine). In study completers, analysis by repeated measures ANOVA revealed no significant difference between olanzapine and placebo groups in BPRS psychosis reduction (p=0.536), parkinsonism (p=0.608), or any other measured parameters (CGI, MMSE, Beck Depression Inventory, Hamilton Depression score, PDQ‑39, Schwab-England ADL assessment, and sleep scores).

Conclusion: This study adds to other evidence that olanzapine is ineffective in treating medication-induced psychosis in Parkinson disease.

Pharmacological recommendations for the symptomatic treatment of dementia: the Canadian Consensus Conference on the Diagnosis and Treatment of Dementia 2012

BACKGROUND

While there have been no new medications approved for the treatment of Alzheimer's disease (AD) or other dementias in Canada since 2004, the Canadian Consensus Conference on the Diagnosis and Treatment of Dementia (CCCDTD) reviewed and updated the clinical practice guidelines on the pharmacological management of dementia that were published previously.

METHODS

This review focused on the literature for the pharmacological treatment of dementia based on studies published since the third CCCDTD in 2006. A literature search of English-language medical databases was preformed for studies pertaining to the pharmacological treatment of AD and other dementias that examined the management of cognitive and functional impairment, as well as neuropsychiatric symptoms. All previous recommendations were reviewed, and only those that required updating based on new published studies were revised. Several new recommendations were also added. Recommendations were rated for quality of evidence and were approved by consensus.

RESULTS

There were 15 revised or new recommendations approved by consensus. The revised recommendations included acknowledging that cholinesterase inhibitors (ChEIs) possess a class effect and any of the agents can be used for AD across the spectrum of severity and with co-existing cerebrovascular disease. There was insufficient evidence to recommend for or against the use of ChEIs in combination with memantine for the primary indication of treating neuropsychiatric symptoms, or for the treatment of vascular dementia. Recommendations for the discontinuation of cognitive enhancers were revised and clarified, as well as the risks associated with discontinuing these drugs. ChEIs were recommended as a treatment option for dementia with Parkinson's disease. Risks associated with use of antipsychotics for neuropsychiatric symptoms were strengthened, and guidelines regarding the use of antidepressants for affective disturbances in dementia were weakened, and are now considered an option but not a firm recommendation. Valproate was recommended not to be used, and there was insufficient evidence to recommend for or against the use of selective serotonin reuptake inhibitors or trazodone for the treatment of agitation and aggression.

CONCLUSION

In spite of the lack of new therapeutic agents for the treatment of dementia, recent studies have helped to clarify and strengthen recommendations to optimize the pharmacological management of these illnesses.

Depression in Parkinson's disease: identification and management

Depression is a common psychiatric comorbidity in Parkinson's disease (PD) and contributes to significant impairments in cognitive, functional, motor, and social performance. This results in reduced quality of life, higher levels of care dependency, and increased caregiver burden. When treating depression, it is important to ensure that the patient's response to treatment will be adequately monitored. This can be accomplished in neurology or primary care settings, or in clinical settings with interdisciplinary treatment teams. Mental health services should be engaged early as a component of ongoing comprehensive care. This article reviews a general approach to treating the pharmacotherapy of depression in PD. Ultimately, clinicians should rely on empiric assessments of known risks and putative benefits to guide treatment decisions and should include a targeted and individualized multimodal approach that utilizes psychotherapeutic interventions along with pharmacologic therapies.

Nonmotor symptoms in Parkinson's disease: expanding the view of Parkinson's disease beyond a pure motor, pure dopaminergic problem

Nonmotor symptoms (NMS) of Parkinson's disease (PD) are critical to identify and treat because of their impact on quality of life. Despite growing evidence of the importance of NMS on patients' quality of life, gaps remain in their recognition and treatment. The result is a need for increased information and understanding of specific NMS and the clinical approaches for their assessment and management in the context of PD as a whole. This article discusses the NMS of PD, their relationship to the pathologic basis of PD, and how NMS can be best managed.

The management of orthostatic hypotension in Parkinson's disease

Orthostatic hypotension (OH) is a common and disabling symptom affecting Parkinson's disease (PD) patients. We present the effect of the different therapies commonly used to manage PD on this clinical manifestation. For this purpose, we describe the relationship between OH and the current treatments employed in PD, such as L-DOPA, dopaminergic agonists, and continuous dopaminergic stimulation therapies. Additionally, we review the therapeutic measures that could be used to ameliorate OH. There are different approaches to deal with this manifestation, including pharmacological and non-pharmacological treatments, although none of them is specifically aimed for treating OH in PD.

Mirtazapine improves visual hallucinations in Parkinson's disease: a case report

Psychotic symptoms often occur as a complication in Parkinson's disease patients, and a set of criteria for Parkinson's disease with psychosis (PDPsy) has been established. Among these criteria, hallucinations are one of the specific symptoms, with visual hallucinations being the most common. While atypical antipsychotic agents are often used for the treatment of PDPsy, adverse effects, including extrapyramidal symptoms, often hinder its continuation or tolerance. There have been some reports and reviews indicating that antidepressants may be effective for PDPsy and other forms of dementia with psychosis. In this report, we present a patient with PDPsy who was treated with one of the new-generation antidepressants, mirtazapine. Mirtazapine improved the patient's refractory psychotic symptoms, especially her visual hallucinations, without worsening her motor symptoms.

Sialorrhea: anatomy, pathophysiology and treatment with emphasis on the role of botulinum toxins

Sialorrhea or excessive drooling is a major issue in children with cerebral palsy and adults with neurodegenerative disorders. In this review, we describe the clinical features, anatomy and physiology of sialorrhea, as well as a review of the world literature on medical treatment using Yale University’s search engine; including but not limited to Medline and Erasmus. Level of drug efficacy is defined according to the guidelines of American Academy of Neurology. Current medical management is unsatisfactory. Topical agents (scopolamine and tropicamide) and oral agents (glyccopyrolate) combined render a level B evidence (probably effective); however, this treatment is associated with troublesome side effects. Double-blind and placebo-controlled studies of botulinum toxin (BoNT) provide a level A evidence for type B (two class I studies; effective and established) and both overall and individual B level of evidence for OnabotulinumtoxinA (A/Ona) and AbobotulinumtoxinA (A/Abo); these are probably effective. For IncobotulinumtoxinA (A/Inco), the level of evidence is U (insufficient) due to lack of blinded studies. Side effects are uncommon; transient and comparable between the two types of toxin. A clinical note at the end of this review comments on fine clinical points. Administration of BoNTs into salivary glands is currently the most effective way of treating sialorrhea.

[Depression and neurological diseases]

In many neurological diseases a depressive syndrome is a characteristic sign of the primary disease or is an important comorbidity. Post-stroke depression, for example, is a common and relevant complication following ischemic brain infarction. Approximately 4 out of every 10 stroke patients develop depressive disorders in the course of the disease which have a disadvantageous effect on the course and the prognosis. On the other hand depression is also a risk factor for certain neurological diseases as was recently demonstrated in a meta-analysis of prospective cohort studies which revealed a much higher stroke risk for depressive patients. Furthermore, depression plays an important role in other neurological diseases with respect to the course and quality of life, such as Parkinson's disease, multiple sclerosis and epilepsy. This article gives a review of the most important epidemiological, pathophysiological and therapeutic aspects of depressive disorders as a comorbidity of neurological diseases and as a risk factor for neurological diseases.

Diagnosis and treatment of impulse control disorders in patients with movement disorders

Impulse control disorders are a psychiatric condition characterized by the failure to resist an impulsive act or behavior that may be harmful to self or others. In movement disorders, impulse control disorders are associated with dopaminergic treatment, notably dopamine agonists (DAs). Impulse control disorders have been studied extensively in Parkinson's disease, but are also recognized in restless leg syndrome and atypical Parkinsonian syndromes. Epidemiological studies suggest younger age, male sex, greater novelty seeking, impulsivity, depression and premorbid impulse control disorders as the most consistent risk factors. Such patients may warrant special monitoring after starting treatment with a DA. Various individual screening tools are available for people without Parkinson's disease. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease has been developed specifically for Parkinson's disease. The best treatment for impulse control disorders is prevention. However, after the development of impulse control disorders, the mainstay intervention is to reduce or discontinue the offending anti-Parkinsonian medication. In refractory cases, other pharmacological interventions are available, including neuroleptics, antiepileptics, amantadine, antiandrogens, lithium and opioid antagonists. Unfortunately, their use is only supported by case reports, small case series or open-label clinical studies. Prospective, controlled studies are warranted. Ongoing investigations include naltrexone and nicotine.

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.

Parkinson's disease: an update on pathogenesis and treatment

The Parkinson's disease research field is a rapidly moving one, as many of the relevant processes underlying PD neurodegeneration are being deciphered, enabling novel approaches to treatment to be assessed both in the laboratory and in the clinic. This review aims to highlight the most relevant updates in the PD field, with emphasis on research that may help lead towards an improvement in the treatment of this condition.

Rotigotine and specific non-motor symptoms of Parkinson's disease: post hoc analysis of RECOVER

BACKGROUND

Non-motor symptoms of Parkinson's disease (PD) represent major causes of morbidity. RECOVER, a randomized controlled trial of rotigotine transdermal system, was the first prospective controlled trial to use the Non-Motor Symptoms Scale (NMSS) as an exploratory outcome for assessment of treatment effects on non-motor symptoms in PD. Rotigotine improved NMSS total score compared with placebo, and the "Sleep/fatigue" and "Mood/apathy" domains. This post hoc analysis further characterizes the effects of rotigotine on sleep/fatigue and mood/apathy.

METHODS

Patients with PD and unsatisfactory early-morning motor impairment were randomized to transdermal patches of rotigotine (2-16 mg/24 h) or placebo. Treatment was titrated to optimal dose over 1-8 weeks, maintained for 4 weeks. The NMSS was assessed at baseline and end of treatment. Post hoc analyses are presented for individual items of the "Sleep/fatigue" and "Mood/apathy" domains. The interpretation of p-values is considered exploratory in nature.

RESULTS

Of 287 patients randomized, NMSS data were available for 267 patients (178 rotigotine, 89 placebo). Within the "Sleep/fatigue" domain there was a significant difference, in favor of rotigotine, in change from baseline score in 1 of 5 items: "fatigue (tiredness) or lack of energy" (ANCOVA, p < 0.0001). Within the "Mood/apathy" domain, there were significant differences in favor of rotigotine in 4 of 7 items: "lost interest in surroundings" (p < 0.0001), "lost interest in doing things" (p < 0.0001), "seems sad or depressed" (p < 0.01), and "difficulty experiencing pleasure" (p < 0.05).

CONCLUSIONS

Rotigotine transdermal system may improve non-motor symptoms such as fatigue, symptoms of depression, anhedonia, and apathy in patients with PD; further prospective controlled studies are required to confirm this post hoc analysis.

Management of motor and non-motor symptoms in Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder that affects approximately 1 % of people over the age of 60 years. Accurate diagnosis and individualized assessment of the risks and benefits of available antiparkinsonian medications as well as specific clinical features and the phase of disease should guide treatment for patients with PD. Levodopa still remains the gold standard for the treatment of motor symptoms of PD but dopamine agonists (DAs), catechol-O-methyltransferase (COMT) inhibitors and monoamine oxidase B (MAO-B) inhibitors have also been developed to provide more continuous oral delivery of dopaminergic stimulation in order to improve motor outcomes and decrease the risk of levodopa-induced motor complications. Deep-brain stimulation as well as other invasive therapies can be used for the treatment of drug-refractory levodopa-induced motor complications. Despite all of the therapeutic advances achieved within the last 20 years, PD continues to be a progressive disorder leading to severe disability caused by motor and non-motor symptoms. To date, neuroprotective interventions able to modify PD progression are not available. This review focuses on medical and invasive treatment strategies for early and advanced stages of PD as well as on the treatment of PD non-motor symptoms such as mood and behavioural disorders, cognitive and autonomic dysfunction, and sleep disorders, which can antedate PD motor symptoms for years.

Risk factors for hallucinations in Parkinson's disease: results from a large prospective cohort study

The aim of this study was to identify risk factors for the development of hallucinations in patients with Parkinson's disease (PD). A broad range of motor and nonmotor features was assessed at baseline and during the following 5 years in 386 PD patients. Cross-sectional analyses of baseline data and longitudinal analyses of follow-up data were performed to identify risk factors for hallucinations in PD. Twenty-one percent of the patients had hallucinations at baseline, whereas 46% of the patients without hallucinations at baseline developed this feature during follow-up. Univariate survival analysis showed that older age, female sex, less education, higher age at onset, and more severe motor and cognitive impairment, depression, daytimes sleepiness, autonomic dysfunction, and motor fluctuations and dyskinesias, as well as higher daily levodopa dose, were associated with the risk of developing hallucinations. This largely corresponds with the features that were associated with the presence of hallucinations at baseline. In a stepwise regression model, older age at onset, female sex, excessive daytime sleepiness, autonomic dysfunction, and dyskinesias emerged as independent risk factors for developing hallucinations. Female sex, autonomic dysfunction, motor fluctuations, and dyskinesias have not been reported as risk factors in previous studies. These findings lend support to the notion that hallucinations in PD are caused by a combination of risk factors that are associated with (the interaction between) older age and more advanced disease. The identification of female sex as a risk factor for developing of hallucinations in PD is a new finding and should be verified in future studies.

Drug-induced dyskinesia in Parkinson's disease. Should success in clinical management be a function of improvement of motor repertoire rather than amplitude of dyskinesia?

BACKGROUND

Dyskinesia, a major complication in the treatment of Parkinson's disease (PD), can require prolonged monitoring and complex medical management.

DISCUSSION

The current paper proposes a new way to view the management of dyskinesia in an integrated fashion. We suggest that dyskinesia be considered as a factor in a signal-to-noise ratio (SNR) equation where the signal is the voluntary movement and the noise is PD symptomatology, including dyskinesia. The goal of clinicians should be to ensure a high SNR in order to maintain or enhance the motor repertoire of patients. To understand why such an approach would be beneficial, we first review mechanisms of dyskinesia, as well as their impact on the quality of life of patients and on the health-care system. Theoretical and practical bases for the SNR approach are then discussed.

SUMMARY

Clinicians should not only consider the level of motor symptomatology when assessing the efficacy of their treatment strategy, but also breadth of the motor repertoire available to patients.

Review: management of Parkinson's disease

Parkinson's disease (PD) is one of the most frequent neurological diseases. Despite the modern imaging and nuclear techniques which help to diagnose it in a very early stage and lead to a better discrimination of similar diseases, PD has remained a clinical diagnosis. The increasing number of available treatment options makes the disease management often complicated even when the presence of PD seems undoubted. In addition, nonmotor symptoms and side effects of some therapies constitute some pitfalls already in the preclinical state or at the beginnings of the disease, especially with the progressive effect on patients. Therefore, this review aimed to summarize study results and depict recommended medical treatments for the most common motor and nonmotor symptoms in PD. Additionally, emerging new therapeutic options such as continuous pump therapies, eg, with apomorphine or parenteral levodopa, or the implantation of electrodes for deep brain stimulation were also considered.

How to treat Parkinson's disease in 2013

Parkinson's disease is a common, progressive, debilitating disease with substantial physical, psychological and social implications. Pharmacological management is complex and should be individualised according to the needs of the patient. In early disease, treatment is generally highly effective, but medication becomes increasingly inadequate in controlling motor fluctuations and dyskinesias as the disease progresses. Non-motor symptoms, especially depression and dementia, require a holistic, multidisciplinary approach to maximise quality of life for patients and their carers. For the future, the ideal solution remains neuroprotection and restoration. Progress has been hampered by the lack of animal models that reflect the widespread brain pathology presumed to cause both motor and non-motor symptoms of PD in humans. Currently, agents are undergoing clinical trials in early, mildly affected patients, such as the plant-derived substance PYM50028 (Cogane), which promotes expression of endogenous neural growth factors and has shown promise in vitro and in animal models. Gene-therapy trials in progress rely on the viral vectors used to deliver the enzymatic machinery required for dopamine synthesis to the striatum. As PD progresses, adequate control of motor symptoms depends increasingly on continuous drug delivery, and greater physiological stimulation of dopamine receptors may help to prevent the development of LIDs and motor fluctuations. Efforts thus are afoot to develop better delivery systems for levodopa, and a new sustained-release formulation is in development.

Management of dysphagia and drooling in patients with Parkinson’s disease

SUMMARY Dysphagia and drooling are frequently reported consequences of Parkinson’s disease (PD) and this article aims to review their management. Several PD-specific and validated instruments are available for the screening and evaluation of dysphagia and drooling, including the Swallowing Disturbance Questionnaire (SDQ), Sialorrhea Clinical Scale for Parkinson’s disease (SCS-PD), Radboud Oral Motor Inventory for Parkinson’s Disease (ROMP), subscales for swallowing and saliva, and non-motor questionnaires that include items on dysphagia and drooling (e.g., Scales for Outcomes in Parkinson’s disease-Autonomic [SCOPA-AUT]; Non-motor Symptoms Questionnaire for Parkinson’s disease [PD-NMSQuest]; and Non-motor Symptoms Assessment Scale for Parkinson’s disease [NMSS]). For the behavioral treatment of dysphagia traditional techniques are helpful, however, exercise training might be more effective. Dysphagia appears to be resistant to drug treatment, but dysphagic patients may benefit from deep brain stimulation. For the treatment of drooling, swallow compensations should be tried, but when saliva reduction is required, botulinum-toxin injections are currently the best option. Overall, there is an urgent need for new approaches to treat dysphagia and drooling in PD.

Morbidities in rapid eye movement sleep behavior disorder

Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD, RBD without any obvious comorbid major neurological disease), is strongly associated with numerous comorbid conditions. The most prominent is that with neurodegenerative disorders, especially synuclein-mediated disorders, above all Parkinson disease (PD). Idiopathic RBD is an important risk factor for the development of synucleinopathies. Comorbidity studies suggest that iRBD is associated with a number of other potential pre-motor manifestations of synucleinopathies such as, cognitive and olfactory impairment, reduced autonomic function, neuropsychiatric manifestations and sleep complaints. Furthermore, patients with PD and RBD may have worse prognosis in terms of impaired cognitive function and overall morbidity/mortality; in dementia, the presence of RBD is strongly associated with clinical hallmarks and pathological findings of dementia with Lewy bodies. These findings underline the progressive disease process, suggesting involvement of more brain regions in patients with a more advanced disease stage. RBD is also associated with narcolepsy, and it is likely that RBD associated with narcolepsy is a distinct subtype associated with different comorbidities. RBD is also associated with antidepressant medications, autoimmune conditions, and, in rare cases, brainstem lesions.

The pharmacologic management of depression in Parkinson's disease

Depression in Parkinson's disease (PD) is common, and it appears to worsen the motor and cognitive progression of the disease, and limits the patient's quality of life. In this paper, we review the pharmacotherapy of depression in people with PD. We find that evidence is sparse when it comes to this patient population. There is some evidence that older tricyclic antidepressants (nortriptyline and desipramine) may be effective in this population. There is also growing evidence that newer antidepressants like paroxetine and venlafaxine may be effective. We will also review a number of other promising medication treatments. What is apparent is the need for more research identifying the most effective medications for treating depression in this population. We provide recommendations that fall in line with current evidence-based practice for managing depression in the general population. Also, we suggest that collaborative models of depression care may be a promising approach to support the identification and effective treatment of those with PD also suffering from depressive disorders.

Methylphenidate : a treatment for Parkinson's disease?

Parkinson's disease (PD) affects about 1 % of the population over the age of 60 years and is characterized by a combination of rest tremor, bradykinesia, rigidity, postural instability, stooped posture and freezing of gait (FoG). However, the clinical spectrum also spans a wide range of non-motor symptoms, such as depression, apathy, cognitive disorders, sleepiness, fatigue and pain. Given that the loss of dopamine in the striatum is the primary pathochemical hallmark in PD, pharmacological treatment of the disease has focused on restoring dopaminergic neurotransmission. The currently licensed dopaminergic treatments for PD modulate all the key steps in the dopamine transmission except the most powerful determinant of extracellular dopamine concentrations: the presynaptic dopamine transporter (DaT). Methylphenidate is a CNS stimulant that blocks the DaT and the noradrenaline (norepinephrine) transporter in the striatum and the prefrontal cortex in particular. Here, we report on and discuss the main open-label studies and randomized controlled trials on the effect of methylphenidate on severe gait disorders (e.g. the FoG) and non-motor symptoms in advanced PD. The various pharmacodynamic effects of methylphenidate mean that the drug may have significant value in the treatment of PD. However, there is a lack of randomized controlled trials in this field. Furthermore, more rigorous selection of the types and doses of the associated dopaminergic treatments is required because these parameters may profoundly influence the mechanisms of action of methylphenidate and the clinical outcomes. Pharmacogenetic tools could be of use in better defining study patients as a function of their dopaminergic metabolism and drug responsiveness.

Cognitive impairment in patients with Parkinson's disease: diagnosis, biomarkers, and treatment

Dementia is one of the most common and important aspects of Parkinson's disease and has consequences for patients and caregivers, and has health-related costs. Mild cognitive impairment is also common and frequently progresses to dementia. The underlying mechanisms of dementia associated with Parkinson's disease are only partly known and no mechanism-based treatments are available. Both dysmetabolism of α-synuclein and amyloid-protein and cholinergic deficits contribute to cognitive impairment in Parkinson's disease, and preliminary findings show that imaging and neurophysiological and peripheral biomarkers could be useful in diagnosis and prognosis. Rivastigmine is the only licensed treatment for dementia in Parkinson's disease, but emerging evidence suggests that memantine might also be useful. Whether these or other treatments can delay the progression from mild cognitive impairment to dementia in Parkinson's disease is a key research question.

Effect of fluoxetine and pergolide on expression of nucleoside transporters and nucleic-related enzymes in mouse brain

Nucleoside transporter (NT) and nucleic-related enzyme (NRE) play key roles in the physiology of nucleosides and the pharmacology of its analogs in mammals. In this study, we examined the effect of fluoxetine, a selective serotonin reuptake inhibitor, and pergolide, a dopamine D receptor agonist, on the expression of NTs and NREs in mouse brain. It was confirmed by the detection of corresponding mRNAs that three equilibrative nucleoside transporter (ENT1-3) isoforms, concentrative nucleoside transporter 2 (CNT2), CNT3, adenosine kinase (AK), and apyrase, but not CNT1, were expressed in brain tissue. Based on an assessment by mRNA determination, the cerebral expression of CNT2 was found to be increased by administration of fluoxetine and pergolide to mice. Furthermore, pergolide increased the expression of ENT2. However, fluoxetine and pergolide had no significant effect on the expression of mRNA for other NTs, AK, and apyrase. Therefore, we concluded that the expression of several NT isoforms, but not NREs, in mouse brain was affected by treatment with fluoxetine and pergolide.

Psychiatric syndromes in Parkinson's disease

PURPOSE OF REVIEW

To examine progress about relevant behavioural and psychiatric disorders in Parkinson's disease, such as depression, apathy, psychosis, and impulse control disorder.

RECENT FINDINGS

Several recent studies have characterized the phenomenology of depression in Parkinson's disease, and randomized controlled trials have demonstrated the efficacy of tricyclics, selective serotonin reuptake inhibitors and psychotherapy for depression in Parkinson's disease. Apathy is a valid behavioural syndrome in Parkinson's disease and is associated with depression and cognitive deficits. Psychosis is highly prevalent in the late stages of the disease, but there are few effective therapeutic modalities for this psychiatric condition. Impulse control disorders are also relatively frequent in Parkinson's disease, and are associated with comorbid psychiatric disorders.

SUMMARY

Standardized criteria should be used to diagnose depression and apathy in Parkinson's disease. Psychotherapy and pharmacotherapy are useful treatment modalities for affective disorders in Parkinson's disease. Clozapine is still the most effective, albeit rarely used, treatment for psychosis in Parkinson's disease. Impulse control disorders are relatively frequent in Parkinson's disease and all patients should be screened for this complex disorder.

Considerations regarding the etiology and future treatment of autosomal recessive versus idiopathic Parkinson disease

OPINION STATEMENT

We postulate that the frequently encountered grouping of different Parkinson disease (PD) variants into a single pathogenetic concept-rather than differentiation into its molecular subtypes-has hindered progress toward curative interventions. Parkinsonism is a clinical syndrome that in rare cases can be explained by a single genetic event or by a single environmental cause, thereby leading to monogenic PD and secondary parkinsonism, respectively. Under the former category, mutations in both alleles of the Parkin-encoding PARK2 gene leads to young-onset, autosomal recessive PD, in which neurodegeneration is restricted to dopamine-producing cells of the brainstem. Under the latter category, exposure to one of several environmental factors with neuroanatomic selectivity can cause rapid-onset, secondary parkinsonism most likely irrespective of the patient's age and genetic makeup. Sandwiched between these two extreme and rare types, the most common variant is referred to as late-onset, idiopathic PD. In extension of a disease model first proposed by Braak et al., we consider idiopathic PD the result of an encounter between one or several environmental triggers and one or more susceptibility alleles. Importantly, this interaction produces a pre-motor syndrome followed by the typical PD phenotype over a period of decades. In our opinion, this pathophysiological process should thus be viewed as a "complex disease." As is true for many complex human disorders, successful intervention for the common PD variant will likely occur when genetic leads as well as environmental contributors are targeted in parallel. However, successful proof-of-concept studies could arrive sooner, namely for select PD variants that can be attributed to a single genetic event and that are neuropathologically restricted. Therefore, the authors decided to focus the second portion of their review on treatment considerations regarding autosomal recessive PD cases that are caused by Parkin deficiency. We briefly draw attention to aspects of existing pharmacological and surgical therapies as they relate to the PARK2-linked variant; thereafter, we comment on new research avenues that are aimed at future therapeutic interventions to eventually slow or arrest the progression of a first variant of PD.

Parasomnias: an updated review

Parasomnias are abnormal behaviors emanating from or associated with sleep. Sleepwalking and related disorders result from an incomplete dissociation of wakefulness from nonrapid eye movement (NREM) sleep. Conditions that provoke repeated cortical arousals, or promote sleep inertia lead to NREM parasomnias by impairing normal arousal mechanisms. Changes in the cyclic alternating pattern, a biomarker of arousal instability in NREM sleep, are noted in sleepwalking disorders. Sleep-related eating disorder (SRED) is characterized by a disruption of the nocturnal fast with episodes of feeding after an arousal from sleep. SRED is often associated with the use of sedative-hypnotic medications; in particular, the widely prescribed benzodiazepine receptor agonists. Recently, compelling evidence suggests that nocturnal eating may in some cases be a nonmotor manifestation of Restless Legs Syndrome (RLS). rapid eye movement (REM) Sleep Behavior Disorder (RBD) is characterized by a loss of REM paralysis leading to potentially injurious dream enactment. The loss of atonia in RBD often predates the development of Parkinson's disease and other disorders of synuclein pathology. Parasomnia behaviors are related to an activation (in NREM parasomnias) or a disinhibition (in RBD) of central pattern generators (CPGs). Initial management should focus on decreasing the potential for sleep-related injury followed by treating comorbid sleep disorders. Clonazepam and melatonin appear to be effective therapies in RBD, whereas paroxetine has been reported effective in some cases of sleep terrors. At this point, pharmacotherapy for other parasomnias is less certain, and further investigations are necessary.

An update on the management of juvenile and young-onset Parkinson’s disease

Early-onset Parkinson’s disease (PD) denotes onset of the disease below the age of 40 years. Patients tend to have a slower disease progression, an increased rate of dystonia, an increased rate of dyskinesias in response to L-3,4-dihydroxyphenylalanine and a lower rate of dementia compared with those in late-onset PD. Early-onset PD patients may experience more social and psychosocial conflict compared with late-onset patients and these factors would contribute to greater impairment of quality of life. Unemployment due to disability or early retirement may be causes for these conflicts. We have to take these factors into account whenever we institute drug therapy in early-onset PD. There is no randomized controlled study on early-onset PD; however, we may make a reasonable decision by considering the data on PD in general and clinical characteristics of early-onset patients. The management of motor and non-motor symptoms of early-onset PD patients is reviewed here.