Restless Legs Syndrome (RLS) and Parkinson's disease (PD)-related disorders or different entities?

Wide-field mosaics of the corneal subbasal nerve plexus in Parkinson's disease using in vivo confocal microscopy

In vivo confocal microscopy (IVCM) is a non-invasive imaging technique facilitating real-time acquisition of images from the live cornea and its layers with high resolution (1-2 µm) and high magnification (600 to 800-fold). IVCM is extensively used to examine the cornea at a cellular level, including the subbasal nerve plexus (SBNP). IVCM of the cornea has thus gained intense interest for probing ophthalmic and systemic diseases affecting peripheral nerves. One of the main drawbacks, however, is the small field of view of IVCM, preventing an overview of SBNP architecture and necessitating subjective image sampling of small areas of the SBNP for analysis. Here, we provide a high-quality dataset of the corneal SBNP reconstructed by automated mosaicking, with an average mosaic image size corresponding to 48 individual IVCM fields of view. The mosaic dataset represents a group of 42 individuals with Parkinson's disease (PD) with and without concurrent restless leg syndrome. Additionally, mosaics from a control group (n = 13) without PD are also provided, along with clinical data for all included participants.

Burning mouth syndrome: An update

Background:

Burning mouth syndrome (BMS) is a chronic and debilitating oral pain of the normal oral mucosa. It mainly affects women in their fifth to seventh decade. Its aetiopathogenesis remains unclear and is probably of multifactorial origin, with increasing evidence that BMS may be a neuropathic disorder. BMS is classified as an idiopathic (nociplastic) orofacial pain with or without somatosensory changes by International Classification of Orofacial Pain (ICOP 2020). The diagnosis of BMS, having excluded ‘oral burning mouth symptoms’, has evolved from basic intraoral exclusion screening to extensive clinical and laboratory investigations, which include the screening of comorbidities and other chronic pains and somatosensory testing. There is no standardised treatment in managing BMS, but a proposed combination of supportive and pharmacological treatment has been recommended.

Aim:

To review the current concepts of BMS definitions, classifications, aetiopathogenesis, diagnosis techniques, and evidence-based treatments in managing BMS patients.

Conclusion:

As BMS is a diagnosis by exclusion, thus a stratified approach is required for assessment of patients presenting BMS. A BMS diagnosis protocol is desired using a standardised screening to distinguish BMS from patient’s presenting with ‘oral burning symptoms’, and evaluation of comorbid chronic pain disorders or other medical comorbidities, which will include haematological, fungal, salivary flow, and qualitative sensory testing. Axis II and other additional quantitative sensory testing may further elucidate the causes of this condition. For future BMS prediction and prevention, will be based upon research on the relationship between other chronic pain disorders and familial history, environmental and genetic information.

Mastering nocturnal jigsaws in Parkinson's disease: a dusk-to-dawn review of night-time symptoms

Finding out about night-time symptoms from Parkinson's disease (PD) patients can be a challenge as many patients and their carers cannot recall many symptoms that occur during the night, resulting in an under-recognition or a large variability of responses from clinical interviews and scales. Moreover, technology-based assessments for most night-time symptoms are still not universally available for use in a patient's home environment. Therefore, most physicians rely on their clinical acumen to capture these night-time symptoms based on pieces of patients' history, bedpartner's reports, clinical features, associated symptoms or conditions. To capture more night-time symptoms, the authors identified common nocturnal symptoms based on how they manifest from dusk to dawn with selected features relevant to PD. While some symptoms occur in healthy individuals, in PD patients, they may impact differently. The authors intend this narrative review to provide a practical guide on how these common night-time symptoms manifest and highlight pertinent issues by focusing on prevalence, clinical symptomatology, and specific relationships to PD. It is also important to recognise that PD-specific sleep disturbances increase with advancing disease with additional contributions from ageing, comorbidities, and medication side effects. However, the relative contribution of each factor to individual symptom may be different in individual patient, necessitating clinical expertise for individual interpretation. While there are debatable issues in certain areas, they underlie the complexity of night-time symptoms. Understanding night-time symptoms in PD is like re-arranging jigsaw pieces of clinical information to create, but never complete, a picture for physicians to instigate appropriate management.

Decreased serum ferritin may be associated with increased restless legs syndrome in Parkinson's disease (PD): a meta-analysis for the diagnosis of RLS in PD patients

Objective: Restless legs syndrome (RLS) is one of the most common non-motor symptoms of Parkinson's disease (PD), but its pathogenesis in a PD background is unclear. Abnormal iron metabolism may be involved, in which case it may be a marker of RLS risk. Here, the literature was systematically searched and meta-analyzed to compare iron metabolism markers between PD patients with or without RLS. Method: The databases PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, Web of Science, and SinoMed were searched for case-control and observational studies examining RLS-related changes in iron metabolism in PD, in terms of serum iron, serum ferritin and hemoglobin. Eligible studies were meta-analyzed using Stata 12.0. Results: Meta-analysis of 11 case-control studies showed that serum ferritin concentration was lower in PD patients with RLS than in those without RLS. (95%CI -0.32 to -0.03, p = 0.018). In contrast, levels of serum iron or hemoglobin did not differ significantly between PD patients with or without RLS. Conclusion: This meta-analysis may provide the first reliable pooled estimate of the correlation between abnormal iron metabolism and RLS in PD. The available evidence indicates that levels of ferritin, but not of serum iron or hemoglobin, correlate significantly with RLS in PD, with lower ferritin levels correlating to greater prevalence of RLS.

Probable RBD Associates with the Development of RLS in Parkinson's Disease: A Cross-Sectional Study

Objectives

We aimed to investigate the prevalence of restless leg syndrome (RLS) and exploring the contributing factors that affect the development of RLS in Parkinson's disease (PD) patients.

Methods

A cross-sectional study was conducted consisting of 178 consecutive PD patients from our hospital between October 2015 and August 2016. We divided the participants into two groups, which were PD with RLS and PD with non-RLS. Then, we recorded their demographics and clinical data to draw a comparison between PD with RLS and PD with non-RLS.

Results

23 (12.92%) were diagnosed with RLS among all the enrolled PD patients. Unified Parkinson's Disease Rating Scale III (UPDRS III) and Hamilton Depression Scale (HAMD) scores, probable rapid eye movement sleep behavior disorder (PRBD), and daily levodopa equivalent dose (LED) in the PD with the RLS group were significantly different from those in the PD with the non-RLS group. Daily LED and the scores of UPDRS III and HAMD in PD patients with RLS were all higher than those in PD patients with non-RLS. PRBD, daily LED, and HAMD scores were significantly independent factors contributing to the development of RLS (OR = 4.678, 95% CI 1.372~15.944, P = 0.014; OR = 1.003, 95% CI 1.001~1.005, P = 0.019; OR = 1.094, 95% CI 1.002~1.193, P = 0.045). The severity of RLS was positively correlated with the duration of PD and daily LED (r = 0.438, P = 0.036; r = 0.637, P = 0.001).

Conclusion

PRBD existence, daily LED, and HAMD scores are independent factors for developing RLS in PD patients. PRBD existence is firstly proposed as an independent factor in developing RLS among PD patients. RLS severity in PD patients are positively associated with the duration of PD and daily LED.

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.

[Increased frequency and spread of restlessness as the early manifestation of Parkinson's disease in a woman with restless legs syndrome]

A 57-year-old woman had been suffered from insomnia due to restlessness and abnormal sensation of the left side of the body for 33 years. Since the preceding year of the first visit frequency of the symptoms increased, and the abnormal sensation was spread to the right leg. Her daughter had restless legs syndrome (RLS) since age 20. Neurological examination showed no abnormality. Laboratory test results showed normal ferritin levels. There was no renal dysfunction or anemia. A diagnosis of RLS was made, and her symptoms responded well to pramipexole treatment. However, the patient developed right shoulder pain and right-hand tremor one year and one and a half year after the first visit, respectively. Based on clinical findings and the findings of dopamine transporter scan and cardiac ¹²³I-MIBG scintigraphy, the patient was diagnosed with Parkinson's disease (PD). Careful observation of changes in RLS symptoms is required as an increased frequency and spread of symptoms of RLS could be the early manifestation of PD.

Diagnosis and treatment of restless legs syndrome

Restless legs syndrome (RLS) is a disorder characterized by an irresistible urge to move the legs during rest, usually accompanied by uncomfortable sensations in the affected extremity or extremities. RLS can manifest at any age but prevalence increases with advancing age. This article describes the symptoms of RLS, associated comorbidities, and how to diagnose and manage RLS.

High Frequency of Sleep Disorders in Parkinson's Disease and Its Relationship with Quality of Life

OBJECTIVES

To determine the frequency of major sleep disorders in patients with Parkinson's disease (PD), diagnosed according to the third international classification of sleep disorders, and assess the relationship of those disorders with the quality of life.

METHODS

A cross-sectional study was performed involving 88 consecutive patients with PD from outpatient clinic. Participants were subjected to clinical interviews, assessment using standardized scales (Epworth Sleepiness Scale, PD Questionnaire, Pittsburgh sleep quality index (PSQI) and, for individuals with a diagnosis of RLS/WED, International RLS/WED grading scale), and video-polysomnography.

RESULTS

We observed sleep disorders in 96.5% of the participants, with REM-sleep behavior disorder found in 62.5%, obstructive sleep apnea in 62.5%, insomnia in 55.7%, and restless legs syndrome in 28.4%. We observed a correlation between health-related quality of life with the PSQI and the Epworth sleepiness scale.

CONCLUSION

Patients with PD have a high prevalence of sleep disorders. The quality of sleep and excessive daytime sleepiness significantly affect the quality of life in these individuals.

Restless legs syndrome in Parkinson disease: Clinical characteristics, abnormal iron metabolism and altered neurotransmitters

Relationships among clinical characteristics, iron metabolism and neurotransmitters in Parkinson disease (PD) patients with restless legs syndrome (RLS) remains unclear. We divided 218 patients into PD with and with no RLS (PD-RLS and PD-NRLS) groups by RLS-rating scale (RLS-RS) score. Motor and non-motor symptoms were rated by related scales. Iron and related proteins, and neurotransmitters in cerebrospinal fluid (CSF) and serum were measured. PD-RLS frequency was 40.37%. PD-RLS group had longer duration, higher stage and scores of motor symptoms, depression, anxiety, sleep disorders, fatigue and apathy, and increased transferrin and decreased iron, ferritin, dopamine (DA) and 5-hydroxytryptamine (5-HT) in CSF. In CSF of PD-RLS group, RLS-RS score was positively correlated with transferrin level and negatively correlated with iron and ferritin levels; RLS-RS score was negatively correlated with DA and 5-HT levels; transferrin level was negatively correlated with DA and 5-HT levels, and ferritin level was positively correlated with DA level. In serum, PD-RLS group had decreased iron and transferrin levels, which were negatively correlated with RLS-RS score. PD-RLS was common and severer in motor and some non-motor symptoms. Iron deficiency induced by its metabolism dysfunctions in peripheral and central systems might cause PD-RLS through decreasing brain DA and 5-HT.

Characterizing restless legs syndrome and leg motor restlessness in patients with Parkinson's disease: A multicenter case-controlled study

BACKGROUND

We investigated the prevalence and impact of restless legs syndrome (RLS) and leg motor restlessness (LMR) in patients with Parkinson's disease (PD) in a multicenter study.

METHODS

A total of 436 PD patients and 401 age- and sex-matched controls were included in this study. RLS was diagnosed based on four essential features. LMR was diagnosed when a participant exhibited the urge to move his or her legs but did not meet the four essential features of RLS.

RESULTS

The RLS prevalence did not differ between PD patients and controls (3.4% vs. 2.7%), while LMR prevalence was significantly higher in PD patients than in controls (12.8% vs. 4.5%). PD patients with RLS or LMR had a higher prevalence of excessive daytime sleepiness (EDS) (50.7%, vs. 6.9%), probable REM sleep behavior disorder (38.0% vs. 3.4%) and PD-related sleep problems (49.3% vs. 20.7%) than controls with RLS or LMR. RLS/LMR preceding PD onset was related to an older age of PD onset.

CONCLUSION

Our study revealed an increased prevalence of LMR but not RLS in PD patients. LMR could be an early manifestation of PD; however, whether LMR is within the range of RLS or whether LMR and RLS constitute different entities in PD requires further studies.

SLEEP AND CIRCADIAN RHYTHM DISORDERS IN PARKINSON'S DISEASE

Purpose of review

Sleep disorders are among the most challenging non-motor features of Parkinson's disease (PD) and significantly affect quality of life. Research in this field has gained recent interest among clinicians and scientists and is rapidly evolving. This review is dedicated to sleep and circadian dysfunction associated with PD.

Recent findings

Most primary sleep disorders may co-exist with PD; majority of these disorders have unique features when expressed in the PD population.

Summary

We discuss the specific considerations related to the common sleep problems in Parkinson's disease including insomnia, rapid eye movement sleep behavior disorder, restless legs syndrome, sleep disordered breathing, excessive daytime sleepiness and circadian rhythm disorders. Within each of these sleep disorders, we present updated definitions, epidemiology, etiology, diagnosis, clinical implications and management. Furthermore, areas of potential interest for further research are outlined.

Restless legs syndrome in Wilson's disease: frequency, characteristics, and mimics

OBJECTIVE

To determine characteristics, clinical significance, frequency, and mimics of restless legs syndrome (RLS) in a cohort of Wilson's disease (WD, n = 42/f = 18), compared to healthy, matched controls.

MATERIALS AND METHODS

Structured clinical interviews (patients and caregiving family members), repeated neurological examinations (afternoon and presleep), comprehensive laboratory tests, WD-, RLS-, and sleep-specific rating scales, and video-polysomnography.

RESULTS

Thirteen patients with WD (13/42 = 31.0%) clearly fulfilled the five diagnostic criteria of RLS; in eight patients (19.1%), the burden of RLS was clinically significant. The RLS was of moderate severity, equally distributed among sexes, manifested mainly in the evening and before falling asleep, and had developed mostly after clinical manifestation of WD (time elapsed 10.2 ± 14.5 years), still at a young mean age (27.5 ± 11.5 years). The known RLS-associated features were absent (normal iron and kidney parameters) or rare (positive family history, polyneuropathy). Compared to WD patients without RLS, patients with RLS were significantly elder and had suffered longer from WD. WD-specific RLS mimics as well as RLS confounding motor comorbidities (dystonia, tremor, chorea) were frequent and a diagnostic challenge; in difficult cases, the differentiation was reached by clinical observation of the motor behavior in the evening or at nighttime.

CONCLUSION

RLS was frequent in this cohort of WD and might be causally related to WD. RLS should be included in the diagnostic work-up of WD. In complex motor disorders, differential diagnosis of RLS might require evening/nighttime examination and video-polysomnography. In WD patients with a clinically significant RLS, treatment with dopaminergic substances may be considered.

A Review of Sleep and Its Disorders in Patients with Parkinson's Disease in Relation to Various Brain Structures

Sleep is an indispensable normal physiology of the human body fundamental for healthy functioning. It has been observed that Parkinson's disease (PD) not only exhibits motor symptoms, but also non-motor symptoms such as metabolic irregularities, altered olfaction, cardiovascular dysfunction, gastrointestinal complications and especially sleep disorders which is the focus of this review. A good understanding and knowledge of the different brain structures involved and how they function in the development of sleep disorders should be well comprehended in order to treat and alleviate these symptoms and enhance quality of life for PD patients. Therefore it is vital that the normal functioning of the body in relation to sleep is well understood before proceeding on to the pathophysiology of PD correlating to its symptoms. Suitable treatment can then be administered toward enhancing the quality of life of these patients, perhaps even discovering the cause for this disease.

The clinical challenges of akathisia

Akathisia is one of the most vexing problems in neuropsychiatry. Although it is one of the most common side effects of antipsychotic medications, it is often difficult to describe by patients, and is difficult to diagnose and treat by practitioners. Akathisia is usually grouped with extrapyramidal movement disorders (ie, movement disorders that originate outside the pyramidal or corticospinal tracts and generally involve the basal ganglia). Yet, it can present as a purely subjective clinical complaint, without overt movement abnormalities. It has been subtyped into acute, subacute, chronic, tardive, withdrawal-related, and "pseudo" forms, although the distinction between many of these is unclear. It is therefore not surprising that akathisia is generally either underdiagnosed or misdiagnosed, which is a serious problem because it can lead to such adverse outcomes as poor adherence to medications, exacerbation of psychiatric symptoms, and, in some cases, aggression, violence, and suicide. In this article, we will attempt to address some of the confusion surrounding the condition, its relationship to other disorders, and differential diagnosis, as well as treatment alternatives.

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.

Parkinson's disease and sleep/wake disturbances

Sleep disturbances are a common non-motor feature in patients with Parkinson's disease (PD). Early diagnosis and appropriate management are imperative for enhancing patient quality of life. Sleep disturbances can be caused by multiple factors in addition to age-related changes in sleep, such as nocturnal motor symptoms (rigidity, resting tremor, akinesia, tardive dyskinesia, and the "wearing off" phenomenon), non-motor symptoms (pain, hallucination, and psychosis), nocturia, and medication. Disease-related pathology involving the brainstem and changes in the neurotransmitter systems (norepinephrine, serotonin, and acetylcholine) responsible for regulating sleep structure and the sleep/wake cycle play a role in emerging excessive daytime sleepiness and sleep disturbances. Additionally, screening for sleep apnea syndrome, rapid eye movement sleep behavior disorder, and restless legs syndrome is clinically important. Questionnaire-based assessment utilizing the PD Sleep Scale-2 is useful for screening PD-related nocturnal symptoms. In this review, we focus on the current understanding and management of sleep disturbances in PD.

Restless legs syndrome in patients with Parkinson's disease: a comparative study on prevalence, clinical characteristics, quality of life and nutritional status

BACKGROUND

Restless legs syndrome (RLS) is a common neurological disorder that can coexist with Parkinson's disease (PD). However, the association between these two movement disorders is quite poorly explored and previous findings are controversial in different aspects.

OBJECTIVE

To compare prevalence of RLS in Iranian PD population with a matched control group and to investigate the impact of comorbid RLS on quality of life (QoL), nutritional status, and clinical characteristics in PD population.

METHODS

This study was conducted on 108 individuals with idiopathic PD (IPD) and 424 matched controls. RLS was diagnosed using the International Restless Legs Syndrome Study Group (IRLSSG) criteria. Further assessments were performed on clinical characteristics, PD severity scales, psychiatric features, nutritional status, fatigue, and QoL in PD patients with and without RLS.

RESULTS

Restless legs syndrome was significantly more common among the patients with IPD (14.8%) compared to the controls (7.5%) [OR = 2.1 (95% CI: 1.1-4.0)]. IPD subjects with RLS had significantly higher anxiety score [10.1 (SD = 5.1) vs 5.9 (SD = 5.0); P = 0.003], worse nutritional status [23.7 (SD = 2.7) vs 25.4 (SD = 3.7); P = 0.008], and poorer QoL [26.9 (SD = 13.1) vs 17.0 (SD = 13.2); P = 0.006]. The number of positive answers to the IRLSSG diagnostic criteria had significant direct correlation with unpredictability of the off periods and the presence of symptomatic orthostasis.

CONCLUSIONS

Our study demonstrated a higher prevalence of RLS in patients with PD compared to general population. PD patients with RLS suffer from more anxiety, worse nutritional status, and worse QoL. RLS negatively accompanies with psychiatric problems, emotional behaviors, stigma, and cognitive impairment.

Diagnosis, comorbidities, and management of restless legs syndrome

OBJECTIVE

This narrative review describes the differential diagnosis of restless legs syndrome, and provides an overview of the evidence for the associations between RLS and potential comorbidities. Secondary causes of RLS and the characteristics of pediatric RLS are also discussed. Finally, management strategies for RLS are summarized.

METHODS

The review began with a comprehensive PubMed search for 'restless legs syndrome/Willis-Ekbom disease' in combination with the following: anxiety, arthritis, attention-deficit hyperactivity disorder, cardiac, cardiovascular disease, comorbidities, depression, end-stage renal disease, erectile dysfunction, fibromyalgia, insomnia, kidney disease, liver disease, migraine, mood disorder, multiple sclerosis, narcolepsy, neuropathy, obesity, pain, Parkinson's disease, polyneuropathy, pregnancy, psychiatric disorder, sleep disorder, somatoform pain disorder, and uremia. Additional papers were identified by reviewing the reference lists of retrieved publications.

RESULTS AND CONCLUSIONS

Although clinical diagnosis of RLS can be straightforward, diagnostic challenges may arise when patients present with comorbid conditions. Comorbidities of RLS include insomnia, depressive and anxiety disorders, and pain disorders. Differential diagnosis is particularly important, as some of the medications used to treat insomnia and depression may exacerbate RLS symptoms. Appropriate diagnosis and management of RLS symptoms may benefit patient well-being and, in some cases, may lessen comorbid disease burden. Therefore, it is important that physicians are aware of the presence of RLS when treating patients with conditions that commonly co-occur with the disorder.

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.

Restless legs syndrome: an early clinical feature of Parkinson disease in men

STUDY OBJECTIVE

The association between restless legs syndrome (RLS) and Parkinson disease has been extensively studied, but the temporal relationship between the two remains unclear. We thus conduct the first prospective study to examine the risk of developing Parkinson disease in RLS.

DESIGN

Prospective study from 2002-2010.

SETTING

United States.

PARTICIPANTS

There were 22,999 US male health professionals age 40-75 y enrolled in the Health Professionals Follow-up Study without Parkinson disease, arthritis, or diabetes mellitus at baseline.

MEASUREMENT AND RESULTS

RLS was assessed in 2002 using a set of standardized questions recommended by the International RLS Study Group. Incident Parkinson disease was identified by biennial questionnaires and then confirmed by review of participants' medical records by a movement disorder specialist. We documented 200 incident Parkinson disease cases during 8 y of follow-up. Compared to men without RLS, men with RLS symptoms who had symptoms greater than 15 times/mo had higher risk of Parkinson disease development (adjusted relative risk = 1.47; 95% confidence interval: 0.59, 3.65; P = 0.41). This was statistically significant only for cases diagnosed within 4 y of follow-up (adjusted relative risk = 2.77; 95% confidence interval: 1.08, 7.11; P = 0.03).

CONCLUSION

Severe restless legs syndrome may be an early feature of Parkinson disease.

Sleep disturbances in Parkinson's disease: the contribution of dopamine in REM sleep regulation

Nearly all patients with Parkinson's disease (PD) have sleep disturbances. While it has been suggested that these disturbances involve a dopaminergic component, the specific mechanisms that contribute to this behavior are far from being fully understood. In this article, we have reviewed the current understanding of the linkage between sleep and PD, focusing on the participation of the dopaminergic system in the regulation of rapid eye movement (REM) sleep. The presence of an REM sleep behavior disorder in patients with PD might reflect the early involvement of dopaminergic neurotransmission in REM sleep-related structures. Therefore, it has been suggested that these structures are affected by an imbalance of dopamine levels. Several studies have demonstrated that neurons in the substantia nigra pars compacta (SNpc) and in the ventral tegmental area (VTA) are active during REM sleep and that sleep-related disturbances may result when these neurons are targeted by neurotoxins. We discuss current evidence suggesting the presence of a putative reciprocal connectivity between the SNpc, VTA, the pedunculopontine tegmental nucleus and reticular formation, which may exert an important influence on the REM sleep mechanism. This review provides a comprehensive overview of the literature that addresses this challenging and unrecognized component of PD.

Recurrent CSPs after Transcranial Magnetic Stimulation of Motor Cortex in Restless Legs Syndrome

Aims. The aim of this study was to investigate the motor control and central silent period (CSP) in restless legs syndrome (RLS). Methods. Transcranial magnetic stimulation was focused on the dominant and nondominant hemispheric areas of motor cortex in six subjects with RLS and six controls. The responses were recorded on the contralateral abductor digiti minimi (ADM) and tibialis anterior (TA) muscles with intramuscular needle electrodes. Results. No significant differences were found in the motor conduction or central motor conduction time, in the latency, or in the duration of the CSPs between or within the groups, but multiple CSPs were observed in both groups. The number of the CSPs was significantly higher in both ADMs and in the dominant TA (P ≤ 0.01) in the RLS group compared to the controls. Conclusion. Descending motor pathways functioned correctly in both groups. The occurrence of the recurrent CSPs predominantly in the RLS group could be a sign of a change of function in the inhibitory control system. Further research is needed to clarify the role of the intramuscular recording technique and especially the role of the subcortical generators in the feedback regulation of the central nervous system in RLS.

Age, drugs, or disease: what alters the macrostructure of sleep in Parkinson's disease?

OBJECTIVE

To describe the alterations in the macrostructure of sleep in a large cohort of sleep-disturbed patients with Parkinson's disease (PD) and investigate influencing factors.

METHODS

A cohort of sleep-disturbed but otherwise unselected PD patients (n=351) was investigated with video-supported polysomnography. We analyzed the influence of age, disease duration, disease severity, and dopaminergic medication on subjective sleep perception, sleep efficiency, the amount of slow wave sleep, awakenings, periodic leg movements in sleep (PLMS), and REM sleep behavior disorder (RBD).

RESULTS

Sleep efficiency and slow wave sleep decreased with age (p=0.003 and p=0.041, respectively). The number of awakenings and the frequency of RBD increased with age (p=0.028 and p=0.006, respectively). Higher Hoehn & Yahr stages were associated with more PLMS (p=0.017). A higher daily dose of levodopa corresponded to more RBD (p<0.001). Neither disease duration nor levodopa dosage had any influence on sleep efficiency, slow wave sleep, awakenings, or PLMS. Dopamine agonists increased awakenings (p<0.001) and lowered PLMS (p<0.001). Subjective sleep perception was not influenced by any of the factors analyzed. The only path model that could be replicated identified disease severity and dopamine agonists as interdependent factors influencing awakenings and PLMS.

CONCLUSION

Age leads to less sleep and a higher risk for RBD, and disease severity increases motor phenomena such as PLMS; dopamine agonists reduce PLMS but increase awakenings. No single factor analyzed influenced subjective sleep perception in this cohort of sleep disturbed PD patients.

Dopa responsive burning mouth syndrome: restless mouth syndrome or oral variant of restless legs syndrome?

Burning mouth syndrome (BMS) is an oral dysesthesia presenting as a burning sensation of the tongue and other oral and perioral mucosae. A painful symptomatology in different bodily regions (extraoral) may also be a common feature in patient with BMS. The management of BMS is challenging and there is no clear guideline for the management of idiopathic BMS. Herein, we describe a group of patients (5 patients) in whom symptoms of BMS responded to levodopa. In parallel, four patients fulfilled the criteria for restless legs syndrome (RLS). Family history of RLS was positive in two patients. We reviewed the literature and noted a marked overlap between BMS and RLS. Overlaps were noted in epidemiological profiles, pattern of clinical features and even in neurophysiological observations (alterations in the striatal dopaminergic system). We suggest that a subset of patients with BMS may be a phenotypic variant of RLS and a trial of dopaminergic drugs should be given in patients with BMS who has a history suggestive of RLS or in a patient who do not show a response to usual therapies for BMS.

Nocturnal disturbances and restlessness in Parkinson's disease: using the Japanese version of the Parkinson's disease sleep scale-2

OBJECTIVE

The aim of this study was to assess the validity and the reliability of the Japanese version of the Parkinson's disease sleep scale (PDSS)-2 and to use this scale to identify nocturnal symptoms and their impact on patient's quality of life.

METHODS

A cross-sectional, case-controlled study was conducted consisting of 93 patients with Parkinson's disease (PD) and 93 age- and gender-matched control subjects. The Japanese version of the PDSS-2 was used for the evaluation of nocturnal disturbances. The patient's quality of life was evaluated with the Parkinson's Disease Quality of Life questionnaire (PDQ-39) and their depressive symptoms were assessed with the Beck Depression Inventory-II (BDI-II), respectively. In addition, the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Parkinson Fatigue Scale (PFS) were administered.

RESULTS

As assessed using the PDSS-2, PD patients had significantly impaired scores compared with control subjects (15.0±9.7 vs. 9.1±6.6, p<0.001). The ESS, BDI-II and PFS scores were significantly impaired in PD patients compared with controls. A satisfactory internal consistency and test-retest reliability score were obtained for the PDSS-2 total score (Cronbach's alpha=0.86). The PDSS-2 was correlated with the PSQI, ESS, BDI-II, PFS, PDQ-39 summary index, all of the PDQ-39 domains and Unified Parkinson's Disease Rating Scale part III. The frequency of restless legs syndrome (RLS) was not significantly different between PD patients and controls (5.5% vs. 2.2%), but nocturnal restlessness was significantly more frequent in PD patients than controls. Stepwise linear regression analyses revealed the PDQ-39 summary index and the PSQI global score as significant predictors for the PDSS-2 total score.

CONCLUSIONS

Our study confirmed the usefulness of the Japanese version of the PDSS-2 that enables the comprehensive assessment of nocturnal disturbances in PD. The association between RLS and nocturnal restlessness in PD requires further study.

When Parkinson's disease patients go to sleep: specific sleep disturbances related to Parkinson's disease

Nonmotor symptoms of Parkinson's disease can be as disabling as the much better studied motor symptoms. Among the nonmotor manifestations are numerous forms of alterations of physiologic sleep patterns that may present at different stages during the course of disease. These include changes believed to be primarily related to the underlying neurodegenerative process of the disease as well as those brought about secondarily, for example, by pharmacologic treatment. Also, sleep disturbances seen in Parkinson's disease can range from temporarily increased daytime sleepiness after introduction of a dopamine agonist to the therapeutic regime to specific sleep-related diagnoses such as restless legs syndrome, rapid eye movement sleep behavior disorder, periodic limb movements in sleep, and sleep-related breathing disorders such as obstructive sleep apnea. In this review, we discuss the different specific sleep disturbances that arise in the context of Parkinson's disease with a special emphasis on epidemiology, pathophysiology, and diagnosis.

Increased striatal dopamine transporter density in moderately severe old restless legs syndrome patients

BACKGROUND AND PURPOSE

Dopamine dysregulation in restless legs syndrome (RLS) may be varied by the severity of RLS, which could contribute to the conflicting results from previous functional neuroimaging studies on the central dopaminergic neurotransmission of RLS. The aim of this study was to observe whether reduced striatal dopaminergic neurotransmission is associated with moderate to moderately severe RLS.

METHODS

Thirteen elderly patients with RLS and 12 normal elderly controls were enrolled in the study. All the subjects were dopaminergic-drug naïve and twelve patients with RLS had the severity of moderate to moderately severe degree based on the International Restless Legs Syndrome Study Group (IRLSSG) Severity Scale. We compared dopamine transporter density (DAT) availability and D2 receptor density in the striatum between patients with RLS and controls using [(123)I]2β-carbomethoxy-3β-(4-iodophenyl)tropane single-photon emission computed tomography (SPECT) and [(123)I]iodobenzamide SPECT.

RESULTS

Dopamine transporter density of patients with RLS was increased in the caudate (P = 0.037), posterior putamen (P = 0.041), and entire striatum (P = 0.046) compared with that of normal controls. DAT density was higher in the anterior putamen of patients with RLS than controls, although statistically not significant (P = 0.079). There was no difference in the D2 receptor density between patients with RLS and normal controls in the whole striatum or any of subregions.

CONCLUSIONS

Dysregulation rather than simple upregulation or downregulation of central dopaminergic neurotransmission may underlie the pathogenesis of RLS, and decreased dopaminergic neurotransmission may cause moderate to moderately severe RLS in the elderly.

A family with Parkinsonism, essential tremor, restless legs syndrome, and depression

BACKGROUND

Previous epidemiologic and genetic studies have suggested a link between Parkinson disease (PD), essential tremor (ET), and restless legs syndrome (RLS).

METHODS

We describe the clinical, PET, and pathologic characteristics of an extensive kindred from Arkansas with hereditary PD, ET, and RLS. The pedigree contains 138 individuals. Sixty-five family members were examined neurologically up to 3 times from 2004 to 2010. Clinical data were collected from medical records and questionnaires. Genetic studies were performed. Five family members underwent multitracer PET. Two individuals with PD were examined postmortem.

RESULTS

Eleven family members had PD with generally mild and slowly progressive symptoms. Age at onset was between 39 and 74 years (mean 59.1, SD 13.4). All individuals treated with l-dopa responded positively. Postural or action tremor was present in 6 individuals with PD, and in 19 additional family members. Fifteen persons reported symptoms of RLS. PET showed reduced presynaptic dopamine function typical of sporadic PD in a patient with PD and ET, but not in persons with ET or RLS. The inheritance pattern was autosomal dominant for PD and RLS. No known pathogenic mutation in PD-related genes was found. Fourteen of the family members with PD, ET, or RLS had depression. Neuropathologic examination revealed pallidonigral pigment spheroid degeneration with ubiquitin-positive axonal spheroids, TDP43-positive pathology in the basal ganglia, hippocampus, and brainstem, and only sparse Lewy bodies.

CONCLUSION

Familial forms of PD, ET, RLS, and depression occur in this family. The genetic cause remains to be elucidated.

Are dysautonomic and sensory symptoms present in early Parkinson's disease?

Parkinson's disease (PD) occurs with an annual incidence of 13/100.000, is slightly more frequent in men and is characterized by the motor symptoms tremor, rigidity, bradykinesia and postural instability. In addition, non-motor symptoms have been increasingly connected to the disease although already described in James Parkinson's 'Essay on the shaking palsy' from 1817. The motor symptoms in PD are related to the degeneration of dopaminergic cells in the substantia nigra (SN). These symptoms respond well to dopaminergic substitution. It is much more unclear whether non-motor symptoms like dysautonomia, insomnia, day-time sleepiness, fatigue, pain and neuropsychiatric symptoms respond to levodopa. Autonomic symptoms include dizziness because of orthostatic hypotension, constipation, nausea, voiding symptoms and increased sweating. Such symptoms as well as sensory symptoms like hyposmia and pain are very frequently reported in PD and seem to occur early in the disease process. Braak proposed a sequential model of neuropathology in PD starting with affection of the olfactory bulb and the autonomic innervation of the heart and gut. Affection of SN is seen from Braak stage 3, and limbic and cortical structures are affected in the later stages of the disease. Currently, the evidence for sensory and autonomic involvement in PD is reviewed with special focus on the early phase of the disease.

Transcranial brain sonography in Parkinson's disease with restless legs syndrome

Substantia nigra (SN) hyperechogenicity assessed by transcranial brain sonography (TCS) is a characteristic finding in idiopathic Parkinson's disease (PD). In contrast, SN hypoechogenicity on TCS has been recently demonstrated in restless legs syndrome (RLS). RLS is one of the most common sleep problems in PD, but the pathophysiologic relationship between these two disorders has not been thoroughly elucidated. We compared the SN echogenicities of PD patients with and without RLS to investigate whether comorbid RLS in PD affects SN echogenicity and to explain the echogenic differences between idiopathic RLS (iRLS) and secondary PD-related RLS (pRLS). Sixty-three PD patients (median age 64.6 +/- 10.6 years), 40 iRLS patients (53.1 +/- 11.7 years), and 40 healthy controls (69.1 +/- 2.3 years) were enrolled in our study. All subjects answered a sleep questionnaire and underwent TCS. PD patients were subdivided into two groups, PD with RLS (PD+RLS, n = 26) and PD without RLS (PD-RLS, n = 37), and the sonographic findings of each group were compared. Although significant hyperechogenicity was detected in both the SN and SN/midbrain ratios in both PD subgroups compared with the controls and the iRLS group (P < 0.001), there were no significant differences in SN echogenicity between the PD+RLS and PD-RLS groups. Meanwhile, iRLS patients showed significant SN hypoechogenicity. In conclusion, comorbid RLS in PD did not have an impact on the sonographic SN findings. These results suggest that the pathogenesis of pRLS and iRLS involve different mechanisms. Further study will be required to clarify the association between RLS and PD.

Update on the management of restless legs syndrome: existing and emerging treatment options

Restless legs syndrome (RLS) is a sensorimotor disorder, characterized by a circadian variation of symptoms involving an urge to move the limbs (usually the legs) as well as paresthesias. There is a primary (familial) and a secondary (acquired) form, which affects a wide variety of individuals, such as pregnant women, patients with end-stage renal disease, iron deficiency, rheumatic disease, and persons taking medications. The symptoms reflect a circadian fluctuation of dopamine in the substantia nigra. RLS patients have lower dopamine and iron levels in the substantia nigra and respond to both dopaminergic therapy and iron administration. Iron, as a cofactor of dopamine production and a regulator of the expression of dopamine type 2-receptor, has an important role in the RLS etiology. In the management of the disease, the first step is to investigate possible secondary causes and their treatment. Dopaminergic agents are considered as the first-line therapy for moderate to severe RLS. If dopaminergic drugs are contraindicated or not efficacious, or if symptoms are resistant and unremitting, gabapentin or other antiepileptic agents, benzodiazepines, or opioids can be used for RLS therapy. Undiagnosed, wrongly diagnosed, and untreated RLS is associated with a significant impairment of the quality of life.