Association of pain, Parkinson's disease, and restless legs syndrome

Pathological pain: Non-motor manifestations in Parkinson disease and its treatment

In addition to motor symptoms, non-motor manifestations of Parkinson's disease (PD), i.e. pain, depression, sleep disturbance, and autonomic disorders, have received increasing attention. As one of the non-motor symptoms, pain has a high prevalence and is considered an early pre-motor symptom in the development of PD. In relation to pathological pain and its management in PD, particularly in the early stages, it is hypothesized that the loss of dopaminergic neurons causes a functional deficit in supraspinal structures, leading to an imbalance in endogenous descending modulation. Deficits in dopaminergic-dependent pathways also affect non-dopaminergic neurotransmitter systems that contribute to the pathological processing of nociceptive input, the integration, and modulation of pain in PD. This review examines the onset and progression of pain in PD, with a particular focus on alterations in the central modulation of nociception. The discussion highlights the importance of abnormal endogenous descending facilitation and inhibition in PD pain, which may provide potential clues to a better understanding of the nature of pathological pain and its effective clinical management.

Predicting neurodegeneration from sleep related biofluid changes

Sleep-wake disturbances are common in neurodegenerative diseases and may occur years before the clinical diagnosis, potentially either representing an early stage of the disease itself or acting as a pathophysiological driver. Therefore, discovering biomarkers that identify individuals with sleep-wake disturbances who are at risk of developing neurodegenerative diseases will allow early diagnosis and intervention. Given the association between sleep and neurodegeneration, the most frequently analyzed fluid biomarkers in people with sleep-wake disturbances to date include those directly associated with neurodegeneration itself, such as neurofilament light chain, phosphorylated tau, amyloid-beta and alpha-synuclein. Abnormalities in these biomarkers in patients with sleep-wake disturbances are considered as evidence of an underlying neurodegenerative process. Levels of hormonal sleep-related biomarkers such as melatonin, cortisol and orexin are often abnormal in patients with clinical neurodegenerative diseases, but their relationships with the more standard neurodegenerative biomarkers remain unclear. Similarly, it is unclear whether other chronobiological/circadian biomarkers, such as disrupted clock gene expression, are causal factors or a consequence of neurodegeneration. Current data would suggest that a combination of fluid biomarkers may identify sleep-wake disturbances that are most predictive for the risk of developing neurodegenerative disease with more optimal sensitivity and specificity.

Restless Legs Syndrome in Parkinson's Disease

BACKGROUND

Restless legs syndrome (RLS) might worsen sleep quality and quality of life in people with Parkinson's disease (PwPD).

OBJECTIVE

The main aim of the present study is to explore the associations between RLS and sleep, quality of life and other non-motor symptoms (NMS) in a sample of PwPD.

METHODS

We compared the clinical features of 131 PwPD with and without RLS, in a cross-sectional study. We used several validated scales for assessment: the International Restless Legs Syndrome Study Group rating scale (IRLS), Parkinson's Disease Sleep Scale version 2 (PDSS-2), Parkinson's Disease Questionnaire (PDQ-39), Non-Motor Symptoms Questionnaire (NMSQ) and International Parkinson and Movement Disorder Society Non-Motor Rating Scale (MDS-NMS).

RESULTS

Thirty-five patients (26.71%) out of the total PwPD met the RLS diagnostic criteria, without significant differences between male (57.14%) and female (42.87%) (p = 0.431). Higher total scores of PDSS-2 were recorded among PwPD + RLS (p < 0.001), suggesting worse sleep quality. Significant correlations were observed between the diagnosis of RLS and some types of pain (especially nocturnal pain), physical fatigue and probable sleep-disordered breathing, according to the MDS-NMSS assessment.

CONCLUSIONS

RLS has a high frequency in PwPD and it requires proper management, considering its consequences on sleep and quality of life.

Restless Legs Symptoms and Periodic Leg Movements in Sleep Among Patients with Parkinson's Disease

BACKGROUND

The association between restless legs syndrome (RLS) and Parkinson's disease (PD) remains controversial, with epidemiologic and descriptive evidence suggesting some potential overlap while mechanistic/genetic studies suggesting relative independence of the conditions.

OBJECTIVE

To examine a known, objectively measured endophenotype for RLS, periodic leg movements (PLMS) in sleep, in patients with PD and relate that objective finding to restless legs symptoms.

METHODS

We performed polysomnography for one (n = 8) or two (n = 67) consecutive nights in 75 PD patients and examined the association of PLMS with restless legs symptoms.

RESULTS

We found no association between restless legs symptoms and PLMS in PD. Prevalence of both was similar to data reported previously in other PD samples.

CONCLUSION

We interpret these results as suggesting that restless legs symptoms in PD patients may represent a different phenomenon and pathophysiology than RLS in the non-PD population.

The association between restless leg syndrome and anxiety in Parkinson's disease: a case-control study

OBJECTIVE

To shed light on the association between restless leg syndrome (RLS) and anxiety in Parkinson's disease (PD) population.

METHODS

This was a case-control study including 129 PD participants with and without anxiety who presented to the Aerospace Center Hospital in Beijing, China. Anxiety was evaluated by using the Beck Anxiety Index score. RLS was assessed using the minimal diagnostic criteria of the International Restless Legs Study Group and RLS symptom frequency and treatment. We then examined the relationship between RLS and anxiety by logistic regression models and subgroup as well as interaction analyses.

RESULTS

The proportion of RLS in PD with anxiety was significantly higher in the PD without anxiety (p < 0.001). The multivariate logistic regression models indicated that PD participants with RLS had a 5.98-fold higher risk of anxiety in PD than those without RLS (OR, 6.98; 95% CI, 2.77-17.59). Subgroup analyses indicated that PD with RLS tended to be associated with a greater risk of anxiety in all stratified subgroups (adjusted ORs >1). Furthermore, the interaction analyses revealed no interactive role in the association between RLS and anxiety.

CONCLUSIONS

The present case-control study suggests that RLS is an independent risk factor for anxiety in PD patients. Early attention and targeted treatment for RLS may be necessary for mood management in PD. Larger prospective cohort studies are wanted to validate these findings.

Prodromal sensory neuropathy in Pink1-/- SNCAA53T double mutant Parkinson mice

AIMS

Parkinson's disease (PD) is frequently associated with a prodromal sensory neuropathy manifesting with sensory loss and chronic pain. We have recently shown that PD-associated sensory neuropathy in patients is associated with high levels of glucosylceramides. Here, we assessed the underlying pathology and mechanisms in Pink1^-/- SNCA^A53T double mutant mice.

METHODS

We studied nociceptive and olfactory behaviour and the neuropathology of dorsal root ganglia (DRGs), including ultrastructure, mitochondrial respiration, transcriptomes, outgrowth and calcium currents of primary neurons, and tissue ceramides and sphingolipids before the onset of a PD-like disease that spontaneously develops in Pink1^-/- SNCA^A53T double mutant mice beyond 15 months of age.

RESULTS

Similar to PD patients, Pink1^-/- SNCA^A53T mice developed a progressive prodromal sensory neuropathy with a loss of thermal sensitivity starting as early as 4 months of age. In analogy to human plasma, lipid analyses revealed an accumulation of glucosylceramides (GlcCer) in the DRGs and sciatic nerves, which was associated with pathological mitochondria, impairment of mitochondrial respiration, and deregulation of transient receptor potential channels (TRPV and TRPA) at mRNA, protein and functional levels in DRGs. Direct exposure of DRG neurons to GlcCer caused transient hyperexcitability, followed by a premature decline of the viability of sensory neurons cultures upon repeated GlcCer application.

CONCLUSIONS

The results suggest that pathological GlcCer contribute to prodromal sensory disease in PD mice via mitochondrial damage and calcium channel hyperexcitability. GlcCer-associated sensory neuron pathology might be amenable to GlcCer lowering therapeutic strategies.

Melatonin as a Chronobiotic and Cytoprotective Agent in Parkinson's Disease

This article discusses the role that melatonin may have in the prevention and treatment of Parkinson’s disease (PD). In parkinsonian patients circulating melatonin levels are consistently disrupted and the potential therapeutic value of melatonin on sleep disorders in PD was examined in a limited number of clinical studies using 2–5 mg/day melatonin at bedtime. The low levels of melatonin MT1 and MT2 receptor density in substantia nigra and amygdala found in PD patients supported the hypothesis that the altered sleep/wake cycle seen in PD could be due to a disrupted melatonergic system. Motor symptomatology is seen in PD patients when about 75% of the dopaminergic cells in the substantia nigra pars compacta region degenerate. Nevertheless, symptoms like rapid eye movement (REM) sleep behavior disorder (RBD), hyposmia or depression may precede the onset of motor symptoms in PD for years and are index of worse prognosis. Indeed, RBD patients may evolve to an α-synucleinopathy within 10 years of RBD onset. Daily bedtime administration of 3–12 mg of melatonin has been demonstrated effective in RDB treatment and may halt neurodegeneration to PD. In studies on animal models of PD melatonin was effective to curtail symptomatology in doses that allometrically projected to humans were in the 40–100 mg/day range, rarely employed clinically. Therefore, double-blind, placebo-controlled clinical studies are urgently needed in this respect.

[Frequent neurological diseases associated with the restless legs syndrome]

BACKGROUND

Restless legs syndrome (RLS) is a common neurological disease. Studies have shown that RLS is associated with a variety of medical and neurological disorders.

OBJECTIVES

Using the example of three associated neurological diseases, the significance for everyday therapy decisions is assessed.

MATERIAL AND METHODS

A systematic search was carried out in PubMed for all studies with the keyword "RLS" in combination with polyneuropathies (PNP), Parkinson's disease (PD) and multiple sclerosis (MS) and classified according to the methodology in high, medium or low study quality.

RESULTS

Of 16 studies on RLS and MS, 10 were rated as "high". The high association frequency of RLS in MS between 13.3% and 65.1% (the variability possibly originates from different methods) prevents further statements about the prevalence. Within 30 studies on Parkinson's disease 17 were classified as having a high quality. In patients with Parkinson disease RLS occurs most frequently during therapy and is related to the duration of dopaminergic treatment. In patients with polyneuropathy, only 5 out of 24 studies were classified as being of high quality and an increased RLS prevalence was detected for acquired polyneuropathies with heterogeneous data for hereditary forms.

CONCLUSION

There is an increased prevalence of association with RLS for the diseases discussed. This prevalence is possibly determined by the pathophysiology of these disorders. These diseases are possibly characterized by genetic predispositions as well, which can hopefully be classified more accurately in the future.

The challenge of pain in the pharmacological management of Parkinson's disease

Introduction: Pain is a common symptom in Parkinson's disease (PD), impairing quality of life. The clinical appearance and the underlying etiologies are diverse. Different subtypes of pain may occur, with musculoskeletal pain considered to be the most frequent. Often there is also a combination of different causes of pain. There is a lack of controlled studies addressing pain therapy in PD. Areas covered: In this review the authors analyzed the currently available data, taking into account the available publications in the databases, especially PubMed. The authors further provided their expert perspectives on the challenges of treating pain in PD patients. Expert opinion: There is both nociceptive and neuropathic pain and in patients with PD, some PD-related pain and some unrelated. Diagnosis requires a thorough and differentiated history and examination, and targeted diagnostics. Therapeutically, many drugs are used, but the data is unfortunately limited and not specific. Medications used include Parkinson-related, mainly dopaminergic drugs, as well as opioids and non-opioid analgetics, anticonvulsives, antidepressants, and more recently cannabinoids. Currently, therapy is performed nonspecifically, without taking into account the special requirements of PD. Unfortunately, in many cases, pain is resistant to these therapies. In the future, both diagnostic and therapeutic efforts should be made to address this issue.

Sensory neuropathy and nociception in rodent models of Parkinson's disease

Parkinson's disease (PD) often manifests with prodromal pain and sensory losses whose etiologies are not well understood. Multiple genetic and toxicity-based rodent models of PD partly recapitulate the histopathology and motor function deficits. Although far less studied, there is some evidence that rodents, similar to humans, develop sensory manifestations of the disease, which may precede motor disturbances and help to elucidate the underlying mechanisms of PD-associated pain at the molecular and neuron circuit levels. The present Review summarizes nociception and other sensory functions in frequently used rodent PD models within the context of the complex phenotypes. In terms of mechanisms, it appears that the acute loss of dopaminergic neurons in systemic toxicity models (MPTP, rotenone) primarily causes nociceptive hyperexcitability, presumably owing to a loss of inhibitory control, whereas genetic models primarily result in a progressive loss of heat perception, reflecting sensory fiber neuropathies. At the molecular level, neither α-synuclein deposits alone nor failure of mitophagy alone appear to be strong enough to result in axonal or synaptic pathology of nociceptive neurons that manifest at the behavioral level, and peripheral sensory loss may mask central ‘pain’ in behavioral tests. Hence, allostatic combinations or additional challenges and novel behavioral assessments are needed to better evaluate PD-associated sensory neuropathies and pain in rodents.

Summary: Rodent models of Parkinson's disease partially develop prodromal somatosensory and olfactory dysfunctions reminiscent of sensory neuropathies in patients and reveal mechanistic insight, but data are incomplete and fragmented.

Restless Legs Syndrome in Parkinson's Disease Patients: Clinical Features Including Motor and Nonmotor Symptoms

Background and Purpose

We investigated the frequency and clinical features of restless legs syndrome (RLS) in patients with Parkinson's disease (PD).

Methods

This study included 74 PD patients. RLS was diagnosed in face-to-face assessments of all of the subjects based on diagnostic criteria of the International Restless Legs Syndrome Study Group revised in 2003. We analyzed the clinical features of PD patients with and without RLS and compared the data to idiopathic RLS.

Results

The frequency of RLS in the cohort was 21.6% (n=16). Two (12.5%) of the patients with RLS were not treated with dopaminergic drugs, while 14 (24.1%) of the 58 patients without RLS received treatment with dopaminergic drugs. Anxiety, depression, and quality of life (QoL) were significantly worst in patients with RLS. PD patients with RLS had significantly worse sleep quality (p=0.003) and worse scores on the cardiovascular subscale of the Scales for Outcomes in Parkinson's Disease for Autonomic Symptoms (p=0.031) compared to those without RLS. In the group of PD patients with RLS, RLS preceding PD onset was related to a lower Hoehn and Yahr stage.

Conclusions

We found that the frequency of RLS in the present patients with PD was higher than that in our previous study of a general population of RLS subjects. Compared to the PD patients without RLS, the present PD patients with RLS suffered from worse sleep quality and QoL, depression, anxiety, and autonomic disturbances, especially those with cardiovascular problems.

Restless Legs Syndrome and Parkinson Disease: A Causal Relationship Between the Two Disorders?

Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a common sleep related movement disorder that can be idiopathic or occurs in comorbidity with other medical conditions such as polyneuropathy, iron deficiency anemia, multiple sclerosis, hypertension and cardiovascular diseases. In recent years, a growing body of literature investigated the association between RLS/WED and Parkinson's Disease (PD). Several questions regarding the comorbidity between these two disorders are still unanswered. If the insurgence of RLS/WED may precede the onset of PD, or if RLS/WED could represent a secondary condition of PD and if impaired dopaminergic pathway may represent a bridge between these two conditions are still debatable issues. In this review, we critically discuss the relationship between RLS/WED and PD by reviewing cross sectional and longitudinal studies, as well as the role of dopamine in these disorders. A twofold interpretation have to be taken into account: dopaminergic therapy may have a crucial role in the development of RLS/WED in PD patients or RLS/WED can be conceived as an early manifestation of PD rather than a risk factor. Several studies showed a high prevalence of RLS/WED in PD patients and several findings related to dopaminergic and iron alterations in both disorders, however up to now it is difficult to find a point of agreement between studies. A greater number of systematic and strongly controlled longitudinal studies as well as basic pathophysiological investigations particularly in RLS/WED are needed to clarify this complex relationship.

Osteoarthritis Increases Paresthestic and Akathisic Pain, Anxiety Case-ness, and Depression Severity in Patients With Parkinson's Disease

Objective: Parkinson's disease (PD) patients are known to suffer from pain, anxiety, and depression, but the exact degree of association between the two is unknown. As many PD patients also suffer from physical impairments, this cross-sectional case-control study sets out to compare and determine the case-ness of pain, anxiety and depression in PD patients that suffer with or without symptomatic osteoarthritis (OA). The goal of this study, therefore, was to observe if additional pain associated with comorbid OA in PD patients is correlated with greater depression and anxiety rates. The importance of understanding the burden of pain and increased depression severity of PD and OA patients is so that they may be screened appropriately based on the symptoms, which may increase their overall quality of life. Methods:This cross-sectional case-control study included 3 groups of 34 patients and 78 healthy age and gender-matched control participants. PD patients with symptomatic OA (PD+OA), PD patients without symptomatic OA (PD), patients with symptomatic OA but no PD (OA), and healthy control participants (Control). A PD patient group with Restless Legs Syndrome (PD+RLS) of 27 patients was also included. All participants completed questionnaires to assess for pain, depression, and anxiety. Results:PD+OA and PD patients had worsened depression severity and were more likely to report anxiety and depression case-ness than OA patients. PD+OA patients were more likely to complain about paresthestic and akasthisic pain, but less likely to complain about aching pain compared to PD patients and OA patients. PD+OA patients were more likely to have greater pain severity, and were more likely to report radiating and sharp pain than PD+RLS patients. PD+OA patients were also more likely to report higher depression case-ness than PD+RLS patients. Conclusion:PD with OA seems to be linked with specific pain characteristics (akathisia and paraesthesia) as well as heightened overall pain severity and pain interference in comparison to OA alone, PD alone and PD with RLS. PD is also correlated with depression severity and anxiety case-ness in OA when compared to the OA alone, PD alone and PD with RLS.

A systematic review of the literature on disorders of sleep and wakefulness in Parkinson's disease from 2005 to 2015

Sleep disorders are among the most common non-motor manifestations in Parkinson's disease (PD) and have a significant negative impact on quality of life. While sleep disorders in PD share most characteristics with those that occur in the general population, there are several considerations specific to this patient population regarding diagnosis, management, and implications. The available research on these disorders is expanding rapidly, but many questions remain unanswered. We thus conducted a systematic review of the literature published from 2005 to 2015 on the following disorders of sleep and wakefulness in PD: REM sleep behavior disorder, insomnia, nocturia, restless legs syndrome and periodic limb movements, sleep disordered breathing, excessive daytime sleepiness, and circadian rhythm disorders. We discuss the epidemiology, etiology, clinical implications, associated features, evaluation measures, and management of these disorders. The influence on sleep of medications used in the treatment of motor and non-motor symptoms of PD is detailed. Additionally, we suggest areas in need of further research.

Rating Scales for Pain in Parkinson's Disease: Critique and Recommendations

BACKGROUND

We aimed at critically appraising the clinimetric properties of existing pain scales or questionnaires and to give recommendations for their use in Parkinson's disease (PD).

METHODS

Clinimetric properties of pain scales used in PD were systematically evaluated. A scale was classified as 'recommended' if was used in PD, showed adequate clinimetric properties, and had been used by investigators other than the original developers; as 'suggested' if it was used in PD and fulfilled only one other criterion; and as 'listed' if it was used in PD but did not meet the other criteria. Only scales rating pain intensity or for syndromic classification were assessed.

RESULTS

Eleven of the 34 scales initially considered fulfilled inclusion criteria. Among the scales rating pain intensity, the "Brief Pain Inventory short form," "McGill Pain Questionnaire short and long forms," "Neuropathic Pain Symptoms Inventory," "11-point Numeric Rating Scale," "10-cm Visual Analog Scale," and "Pain-O-Meter" were "recommended with caution" because of lack of clinimetric data in PD, whereas the "King's PD Pain Scale" was "recommended." Among scales for pain syndromic classification, the "DN4" was "recommended with caution" because of lack of clinimetric data in PD; the "Leeds Assessment of Neuropathic Symptoms and Signs," "Pain-DETECT," and the "King's PD Pain Scale" were "suggested."

CONCLUSIONS

King's PD pain scale can be recommended for the assessment of pain intensity in PD. Syndromic classification of pain in PD may be achieved by the DN4, but clinimetric data in PD are needed for this scale.

Classification and Characteristics of Pain Associated with Parkinson's Disease

Neuropsychiatric symptoms and pain are among the most common nonmotor symptoms of Parkinson's disease (PD). The correlation between pain and PD has been recognized since its classic descriptions. Pain occurs in about 60% of PD patients, two to three times more frequent in this population than in age matched healthy individuals. It is an early and potentially disabling symptom that can precede motor symptoms by several years. The lower back and lower extremities are the most commonly affected areas. The most used classification for pain in PD defines musculoskeletal, dystonic, central, or neuropathic/radicular forms. Its different clinical characteristics, variable relationship with motor symptoms, and inconsistent response to dopaminergic drugs suggest that the mechanism underlying pain in PD is complex and multifaceted, involving the peripheral nervous system, generation and amplification of pain by motor symptoms, and neurodegeneration of areas related to pain modulation. Although pain in DP is common and a significant source of disability, its clinical characteristics, pathophysiology, classification, and management remain to be defined.

Associations of pain and depression with marital status in patients diagnosed with Parkinson's disease

BACKGROUND

Depression and pain are significant clinical problems that are comorbid with Parkinson's disease (PD). However, the relationship of these variables with the marital status of patients with PD has not been explored in previous studies. Therefore, the goal of this study was to assess the possible relationship between depression prevalence, depression severity, and pain interference with the marital status of the sufferers of PD.

METHODS

This study included 40 patients and 40 healthy control participants who were assessed for depression prevalence and severity using The Hospital Anxiety and Depression Scale (HADS). The same individuals were also assessed for pain interference using the Brief Pain Inventory (BPI).

RESULTS

When compared to the control groups, the PD (Single) group was found to have the highest prevalence of depression, followed by the PD (Married) group whereas the Control (Single) group was found to have a higher prevalence than the Control (Married) group (P < 0.0001). A main effect was found on depression severity (P < 0.0001), but no significant differences were observed between the PD groups. Lastly, PD (Single) patients had significantly greater pain interference scores than the PD (Married) patients (P < 0.05) with no other significant case-control or control-control group differences.

CONCLUSION

Patient-spouse relationship, which indicates physical and emotional support may have a mitigating effect on patient outcomes of depression prevalence and pain interference.

Parkinson's disease: a review of non-motor symptoms

Parkinson's disease (PD) is a neurodegenerative disorder resulting from degeneration of the substantia nigra and the dopaminergic nigrostriatal pathway. Most treatments are geared toward the management and relief of motor symptoms in Parkinson's patients; however, as the disease progresses, various complications can be observed. Non-motor symptoms (NMS) may arise simply from the disease itself and are highly destructive to quality of life. These symptoms include mood disorders, cognitive dysfunction, pain, sensory dysfunction, and dysautonomia. Though it is undisputed that many NMS may appear years or even decades prior to the clinical diagnosis of PD, the focus of this review will be the overt motor phase of the condition. As such, the focus of this paper is to review the major NMS found in PD patients status post-diagnosis, their etiology, as well as treatment options available for the individual NMS.

Restless Legs Syndrome and Leg Motor Restlessness in Parkinson's Disease

Sleep disturbances are important nonmotor symptoms in Parkinson's disease (PD) that are associated with a negative impact on quality of life. Restless legs syndrome (RLS), which is characterized by an urge to move the legs accompanied by abnormal leg sensations, can coexist with PD, although the pathophysiology of these disorders appears to be different. RLS and PD both respond favorably to dopaminergic treatment, and several investigators have reported a significant relationship between RLS and PD. Sensory symptoms, pain, motor restlessness, akathisia, and the wearing-off phenomenon observed in PD should be differentiated from RLS. RLS in PD may be confounded by chronic dopaminergic treatment; thus, more studies are needed to investigate RLS in drug-naïve patients with PD. Recently, leg motor restlessness (LMR), which is characterized by an urge to move the legs that does not fulfill the diagnostic criteria for RLS, has been reported to be observed more frequently in de novo patients with PD than in age-matched healthy controls, suggesting that LMR may be a part of sensorimotor symptoms intrinsic to PD. In this paper, we provide an overview of RLS, LMR, and PD and of the relationships among these disorders.

Impact of ethnicity on mood disorders in Parkinson's disease

Anxiety and depression are common in Parkinson's disease (PD) patients, yet their prevalence and severity compared to individuals without PD requires more research. Moreover, it has never been compared across different ethnic groups. The objective of this study was to close that gap in the literature by exploring the caseness and severity of anxiety and depression in PD patients of different ethnicities compared to controls without PD. It was found that caseness and severity of anxiety and depression are higher in individuals with PD compared to controls. Furthermore, the caseness and severity of anxiety and depression do not vary significantly among ethnic groups. Finally, depression caseness was not predicted by age, gender, disease duration, restless legs syndrome prevalence, Hoehn and Yahr (H&Y) score nor Unified Parkinson's disease rating scale part III (UPDRS-III) score. Anxiety caseness was predicted by gender, with females 2.7 times more likely to have anxiety caseness than males. Overall, our study suggests that treatment plans should be individualized based on prevalence and severity of the two conditions in individuals with PD rather than generalize treatment for specific ethnic groups.

Prevalence comparisons of somatic and psychiatric symptoms between community nonpatients without pain, acute pain patients, and chronic pain patients

OBJECTIVES

Somatic/psychiatric symptoms are frequently found in chronic pain patients (CPPs). The objectives of this study were to determine 1) which somatic/psychiatric symptoms are more commonly found in acute pain patients (APPs) and CPPs vs community nonpatients without pain (CNPWPs) and 2) if somatic/psychiatric symptom prevalence differs between APPs and CPPs.

DESIGN

The above groups were compared statistically for endorsement of 15 symptoms: fatigue, numbness/tingling, dizziness, difficulty opening/closing mouth, muscle weakness, difficulty staying asleep, depression, muscle tightness, nervousness, irritability, memory, falling, nausea, concentration, and headaches.

RESULTS

After controlling for age, gender, and level of pain, APPs and CPPs had a statistically significantly greater prevalence (at a P < 0.01 level) for 11 and 13 symptoms, respectively, vs CNPWPs. After controlling for age, gender, and level of pain, CPPs had a statistically significantly greater prevalence (at a P < 0.01 level) for eight symptoms vs APPs. Symptoms were highly correlated in both APPs and CPPs.

CONCLUSIONS

CPPs are characterized to a significantly greater extent than comparison groups by somatic/psychiatric symptoms that are highly intercorrelated. This has implications for clinical practice and future research.

Restless legs syndrome in Parkinson's disease

The Restless legs syndrome (RLS) and Parkinson's disease (PD) are two disorders that can co-exist, whether or not they share a common pathophysiology. If, and to what extent RLS and PD share the same pathophysiology, is still under debate. Sleep disturbances are prevalent in PD, and as PD progresses, nocturnal disturbances become even more evident, in association not only with motor symptoms but also with non-motor symptoms. Alertness to, and recognition of, RLS in PD patients with sleep disorders could improve customized treatment and quality of life of these patients. In this article the prevalence of RLS in PD, the clinical profile of RLS in PD, the PD profile of patients with RLS, RLS mimics specifically related to PD and impact of RLS in PD will be reviewed.

Sensory aspects of movement disorders

Movement disorders, which include disorders such as Parkinson's disease, dystonia, Tourette's syndrome, restless legs syndrome, and akathisia, have traditionally been considered to be disorders of impaired motor control resulting predominantly from dysfunction of the basal ganglia. This notion has been revised largely because of increasing recognition of associated behavioural, psychiatric, autonomic, and other non-motor symptoms. The sensory aspects of movement disorders include intrinsic sensory abnormalities and the effects of external sensory input on the underlying motor abnormality. The basal ganglia, cerebellum, thalamus, and their connections, coupled with altered sensory input, seem to play a key part in abnormal sensorimotor integration. However, more investigation into the phenomenology and physiological basis of sensory abnormalities, and about the role of the basal ganglia, cerebellum, and related structures in somatosensory processing, and its effect on motor control, is needed.