Symptomatic restless leg syndrome after lacunar stroke: A lesion study

Sensorimotor white matter projections and disease severity in primary Restless Legs Syndrome/Willis-Ekbom disease: a multimodal DTI analysis

BACKGROUND

Restless Legs Syndrome, a potentially disabling sleep disorder, also known as Willis-Ekbom disease (RLS/WED), may be caused by loss of inhibitory modulation of descending central motor pathways, structural changes in the somatosensory cortex, abnormal connectivity between motor and sensory areas, as well as by subtle abnormalities in white matter micro-organization.

OBJECTIVE

To compare diffusion-tensor imaging (DTI) metrics in areas associated with sensory or motor function, as well as sensorimotor integration, between subjects with primary mild-to-severe RLS/WED and controls.

METHODS

DTI metrics were assessed in 38 subjects with RLS/WED (14 mild to moderate, 24 severe to very severe) and 24 healthy age-matched controls with whole-brain Tract Based Spatial Statistics (TBSS), Region-of-interest (ROI) and probabilistic tractography based analyses. The ROIs corresponded to the corticospinal tract (CST) at the level of the cerebral peduncle; the superior, middle and inferior cerebellar peduncles. Subgroup analyses were made according to the severity of RLS/WED symptoms. The corticospinal tract was evaluated with probabilistic tractography. We also explored associations between significant findings and severity of symptoms with the Spearman's correlation coefficient.

RESULTS

TBSS analysis revealed decreased axial diffusivity (AD) in the left posterior thalamic radiation in RLS/WED. In subjects with severe RLS/WED, AD was reduced in the left posterior corona radiata and this reduction was negatively correlated with severity of symptoms. ROI-based analysis showed that radial diffusivity (RD) was increased in the superior cerebellar peduncles of individuals with severe RLS/WED. Tractography did not show between-group or subgroup differences.

CONCLUSIONS

Our results are consistent with subtle white matter changes, prominently in RLS/WED subjects with more severe symptoms, in areas related to sensory or motor function, as well as to sensorimotor integration, compared to controls. These findings support the hypothesis, raised by prior pathophysiological studies, of defective integration within these networks.

Restless legs syndrome is associated with arterial stiffness and clinical outcome in stroke patients

OBJECTIVE

Restless legs syndrome (RLS) has been associated with vascular diseases, including cerebrovascular and cardiovascular diseases. Among the various mechanisms in RLS, peripheral vascular endothelial dysfunction in patients with RLS has recently been proposed as a vascular pathophysiology of RLS. This study investigated arterial stiffness related to RLS in acute ischemic stroke patients and its influence on stroke outcome.

METHODS

RLS in patients with acute ischemic stroke was assessed based on the four essential criteria of the International Restless Legs Syndrome Study Group described in 2003. The patients' clinical and laboratory characteristics, arterial stiffness, small vessel disease occurrence, and burden on brain MRI were recorded. Stroke severity was determined using the National Institute of Health Stroke Scale (NIHSS), and clinical outcomes were determined using the modified Rankin Scale.

RESULTS

Of 296 patients with acute ischemic stroke, 16 (5.4%) were diagnosed with restless legs syndrome. Logistic regression analysis showed that a 1 m/s increase in brachial arterial pulse wave velocity was associated with the diagnosis of RLS (odds ratio, 1.092; 95% confidence interval, 1.019-1.170, p = 0.012). Diagnosis of RLS in patients with acute ischemic stroke was associated with poor clinical outcome three months after stroke (modified Rankin Scale 3-6) (odds ratio, 4.263; 95% confidence interval, 1.229-14.792, p = 0.022) along with initial NIHSS score.

CONCLUSION

RLS in patients with acute ischemic stroke is associated with increased arterial stiffness and poor clinical outcomes.

Restless legs syndrome and its variants in acute ischemic stroke

BACKGROUND

The clinical-radiological correlation between restless legs syndrome (RLS) or its variants and acute ischemic stroke remains unclear.

METHODS

This study prospectively included 104 consecutive patients with acute ischemic stroke, confirmed by diffusion-weighted imaging. The frequency and clinical characteristics of RLS or RLS variants were evaluated according to the International RLS Study Group criteria, as was the topography of the associated lesions.

RESULTS

Among 104 patients with acute ischemic stroke, 6 (5.8%) and 2 patients (1.9%) had RLS and RLS variants, respectively, for a total of 8 patients (7.7%). Three (3.3%) had poststroke RLS/RLS variants: 2 (66.7%) had bilateral symptoms and 1 (33.3%) had unilateral symptoms contralateral to the lesion. RLS symptoms developed within 2 days after the onset of stroke. Forty percent of prestroke RLS/RLS variant patients experienced exacerbation of their symptoms after stroke onset, and two-thirds of poststroke RLS/RLS variant patients required treatment for their RLS/RLS variants. Patients positive for RLS/RLS variants tended to have difficulty falling asleep, but there was no difference in daytime sleepiness, sleep quality, depressive symptoms, stroke subtypes, comorbid diseases, laboratory data, or modified Rankin Scale scores at admission or discharge between patients with and without RLS/RLS variants. RLS/RLS variants were most frequently observed to accompany lesions in the medulla (25%), followed by the pons (15.4%), the corona radiata (14.8%), the basal ganglia (3.8%), and the cortex (3.8%).

CONCLUSION

RLS/RLS variants were found in 8% of acute ischemic stroke patients. Adequate screening and management are needed to improve patients' quality of life.

Clinical and radiological characteristics of restless legs syndrome following acute lacunar infarction

BACKGROUND

Recent studies have suggested that cerebral ischemic infarction may contribute to the development of restless legs syndrome (RLS). This study analyzed the clinical and radiological profiles of RLS with onset after acute lacunar infarction.

METHODS

In this retrospective study we enrolled 244 consecutive patients with acute lacunar infarction between January 2012 and June 2014. RLS was identified and evaluated based on the International RLS Rating Scale (IRLS-RS). Individual sleep quality was assessed using the Epworth Sleepiness Scale (ESS). Psychological state was also assessed using the Hamilton Depression Scale (HDS) and the Hamilton Anxiety Scale (HAS).

RESULTS

The incidence of RLS in patients with lacunar infarction was 5.33%. Our participant group consisted of nine males and four females. Three patients had symptoms in bilateral limbs, and 10 patients had symptoms only contralateral to the cerebral infarction. The infarctions were localized to the pons, centrum semiovale, thalamus, putamen, medulla, and occipital lobe. Contralateral paralysis was found in 13 patients, and contralateral sensory deficit in seven patients. The average IRLS-RS, ESS, HDS, HAS scores were 19.07 ± 8.70, 4.69 ± 5.82, 4.38 ± 4.68, and 3.85 ± 4.76, respectively. Nine patients had diabetes mellitus. After administration of dopaminergic drugs, patients' RLS significantly improved.

CONCLUSIONS

The incidence of RLS after acute lacunar infarction was 5.33%. Pons, centrum semiovale, and basal ganglia were the common locations of responsible lesions. Compared to idiopathic RLS, symptoms of RLS after acute lacunar infarction appeared more unilateral and more likely involved the arm. Moreover, diabetes mellitus may be a risk factor for RLS in stroke patients.

Post-stroke Movement Disorders: The Clinical, Neuroanatomic, and Demographic Portrait of 284 Published Cases

PURPOSE

Abnormal movements are a relatively uncommon complication of strokes. Besides the known correlation between stroke location and certain movement disorders, there remain uncertainties about the collective effects of age and stroke mechanism on phenomenology, onset latency, and outcome of abnormal movements.

MATERIALS AND METHODS

We systematically reviewed all published cases and case series with adequate clinical-imaging correlations. A total of 284 cases were analyzed to evaluate the distribution of different movement disorders and their association with important cofactors.

RESULTS

Posterolateral thalamus was the most common region affected (22.5%) and dystonia the most commonly reported movement disorder (23.2%). The most common disorders were parkinsonism (17.4%) and chorea (17.4%) after ischemic strokes and dystonia (45.5%) and tremor (19.7%) after hemorrhagic strokes. Strokes in the caudate and putamen were complicated by dystonia in one third of the cases; strokes in the globus pallidus were followed by parkinsonism in nearly 40%. Chorea was the earliest poststroke movement disorder, appearing within hours, whereas dystonia and tremor manifested several months after stroke. Hemorrhagic strokes were responsible for most delayed-onset movement disorders (>6 months) and were particularly overrepresented among younger individuals affected by dystonia.

CONCLUSIONS

This evidence-mapping portrait of poststroke movement disorders will require validation or correction based on a prospective epidemiologic study. We hypothesize that selective network vulnerability and resilience may explain the differences observed in movement phenomenology and outcomes after stroke.

Acute-onset Restless legs syndrome in acute neurological conditions-a prospective study on patients with the Guillain-Barre syndrome and acute stroke

OBJECTIVES

While the Restless legs syndrome (RLS) is usually recognized as a chronic condition, it has often been diagnosed among patients with acute neurological illnesses, in which limb discomfort is reported. This study was conducted to determine how many among these, actually have acute-onset RLS, and also to evaluate characteristics of this subgroup of patients with Guillain-Barre syndrome (GBS) and stroke developing acute-onset RLS.

METHODS

Consecutive patients diagnosed with GBS and eligible stroke patients, admitted to our Neurology services over a 1-year period, were enrolled. They were evaluated for symptoms of RLS based on IRLSSG consensus criteria and the AIIMS RLS Questionnaire for Indian patients (ARQIP).

RESULTS

Forty adults with GBS and 58 with stroke were included. A total of 10 of the 40 (25%) patients with GBS developed definite acute RLS, which was mostly monophasic. Seven (70%) of these had demyelinating type of GBS, a significant association with acute RLS (P = .024). Six of the 58 stroke patients (10%) developed definite acute-onset, often persistent RLS. Subcortical location showed significant association with increased risk of developing acute RLS (P < .001). All patients diagnosed with acute-onset RLS had an immediate and good response to dopamine agonists.

CONCLUSION

This is the first study showing that acute-onset RLS is common, affecting nearly 25% of patients with GBS and 10% patients with acute stroke. Recognizing and treating it can majorly contribute toward symptom relief and early improvement in the quality of life for this population.

Periodic limb movements during sleep in stroke/TIA: Prevalence, course, and cardiovascular burden

OBJECTIVE

To define the prevalence, time course, and associated factors of periodic limb movements during sleep (PLMS) in patients with ischemic stroke or TIA.

METHODS

Patients enrolled in the prospective Sleep-Disordered Breathing in Transient Ischemia Attack (TIA)/Ischemic Stroke and Continuous Positive Airway Pressure (CPAP) Treatment Efficacy (SAS-CARE) study underwent a double polysomnographic investigation in the acute and chronic phases after stroke/TIA, together with a MRI brain scan and a 24-hour blood pressure evaluation. The prevalence of PLMS in patients was compared with that in a matched sample of randomly selected healthy controls from the HypnoLaus cohort. One hundred sixty-nine recordings were performed in the acute phase and 191 after 3 months (210 recordings were obtained from the same 105 patients in both phases) and were compared to those of 162 controls.

RESULTS

The mean number of PLMS per hour and the percentage of participants with a PLMS index >10 and >15 per hour were similar between patients and controls. PLMS remained stable from the acute to the chronic phase after stroke. Factors positively associated with PLMS were age, body mass index, and history of hypertension. Blood pressure over 24 hours and the burden of cerebrovascular damage were similar between the groups with PLMS and without PLMS.

CONCLUSIONS

PLMS are equally frequent in patients with stroke/TIA and the general population. The absence of higher blood pressure values and of a greater vascular brain damage found in patients with PLMS compared to those without PLMS might be due to a greater use of antihypertensive medication among patients with PLMS, which corresponds to a higher prevalence of previous diagnosis of hypertension in these patients.

The potential impact of sleep-related movement disorders on stroke risk: a population-based longitudinal study

BACKGROUND

Sleep-related movement disorders (SRMD) have been shown to increase the risk of cardiovascular diseases. However, the relationship between SRMD and stroke remains unclear.

AIM

To explore the relationship between SRMD and stroke in the general population.

DESIGN

Two cohorts of patients with SRMD and without SRMD were followed up for the occurrence of hemorrhagic and ischemic stroke.

METHODS

The study cohort enrolled 604 patients who were initially diagnosed as SRMD between 2000 and 2005. 2,416 age- and sex-matched patients without prior stroke were selected as the comparison cohort. A Cox-proportional hazard regression analysis was performed for multivariate adjustment.

RESULTS

Patients with SRMD had a higher risk for developing all-cause stroke [adjusted hazard ratio (HR) = 2.29, 95% confidence interval (CI) = 1.42-3.80]. Patients of below 45 years old had the greatest stroke risk (HR = 4.03, 95% CI = 3.11-5.62), followed by patients aged ≥65 years (HR = 2.64, 95% CI = 1.12-3.44) and 45-64 years (HR = 1.07, 95% CI = 1.02-1.71). The age-stratified analysis suggested that the increased risk of hemorrhagic stroke was more significant than ischemic stroke among all age groups. Furthermore, males with SRMD were at greater risk to develop all-cause stroke (HR = 2.98, 95% CI = 1.74-4.50) than that of females (HR = 1.94, 95% CI = 1.01-3.77).

CONCLUSIONS

Patients with SRMD were found to have an increased risk of all-cause stroke along with a higher possibility of hemorrhagic stroke over ischemic stroke.

Post-stroke restless leg syndrome and periodic limb movements in sleep

OBJECTIVES

Primary restless leg syndrome (RLS) and periodic limb movements in sleep (PLMS) frequently co-exist, obscuring the boundaries between the two conditions. In such instances, a study of secondary cases with focal lesions such as post-stroke RLS and PLMS (psRLS and psPLMS, respectively) can be helpful in identifying characteristics of the individual conditions.

MATERIALS AND METHODS

Patients who had suffered strokes and who subsequently developed psRLS or psPLMS were recruited. To determine the overall features of psRLS/PLMS, historical cases were selected from the literature. All cases with either psRLS or psPLMS alone were further analyzed to elucidate the distinctive pathomechanisms of the two conditions.

RESULTS

Six patients with either psRLS or psPLMS were recruited from our hospital; two patients had both conditions contemporaneously. The literature contains details on 30 cases of psRLS or psPLMS. The causative lesion was most frequently located in the pons. We found that psRLS was more often bilateral, and usually detected later in time. Lesions in both the pontine base and tegmentum (together) were associated with unilateral psPLMS, whereas lesions in the corona radiata and adjacent basal ganglia were associated with bilateral RLS. Lesions confined to the corona radiata resulted in either unilateral or bilateral RLS.

CONCLUSIONS

The observed differences in the clinical and radiological features of psRLS and psPLMS suggest that the pathophysiologies of the two conditions are distinct. Further research is needed to understand the pathophysiologies of primary RLS and PLMS.

DTI and VBM reveal white matter changes without associated gray matter changes in patients with idiopathic restless legs syndrome

BACKGROUND AND PURPOSE

We evaluated cerebral white and gray matter changes in patients with iRLS in order to shed light on the pathophysiology of this disease.

METHODS

Twelve patients with iRLS were compared to 12 age- and sex-matched controls using whole-head diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) techniques. Evaluation of the DTI scans included the voxelwise analysis of the fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD).

RESULTS

Diffusion tensor imaging revealed areas of altered FA in subcortical white matter bilaterally, mainly in temporal regions as well as in the right internal capsule, the pons, and the right cerebellum. These changes overlapped with changes in RD. Voxel-based morphometry did not reveal any gray matter alterations.

CONCLUSIONS

We showed altered diffusion properties in several white matter regions in patients with iRLS. White matter changes could mainly be attributed to changes in RD, a parameter thought to reflect altered myelination. Areas with altered white matter microstructure included areas in the internal capsule which include the corticospinal tract to the lower limbs, thereby supporting studies that suggest changes in sensorimotor pathways associated with RLS.

Restless legs syndrome, a predictor of subcortical stroke: a prospective study in 346 stroke patients

OBJECTIVE

The objective of this study was to assess the prevalence of restless legs syndrome (RLS) among patients with stroke and to examine the anatomical correlation between location of stroke and RLS symptoms.

METHODS

We administered a pre-structured sleep questionnaire to consecutive stroke patients seen in our neurology services department over a 3-year period. Unconscious (Glasgow Coma Scale score <15) or aphasic, renally impaired, or neuropathic patients were excluded. Diagnosis of RLS was established according to the criteria of the International Restless Legs Syndrome Study Group (IRLSSG), and polysomnography was conducted.

RESULTS

Of 346 stroke patients, 35 (10.11%) fulfilled IRLSSG diagnostic criteria for RLS, which had existed for an average (±standard deviation) of 60 ± 40 months before stroke. The mean age of onset was 52.94 (±10.32) years. Twenty-four patients (68%) had RLS symptoms contralateral to the hemisphere involved in the stroke (eight with unilateral and 16 with grossly asymmetrical RLS). Twenty-nine of 35 patients (82.86%) had imaging evidence of subcortical (16 with hemorrhagic and 13 with ischemic) stroke. Patients with pre-stroke RLS differed from those without it only by subcortical location of the stroke (82.9% vs 31.5% respectively, p < 0.001). The most significant differentiating factor between patients with subcortical stroke and those with cortical stroke was pre-stroke RLS (22.83% vs 2.74%, p < 0.001), the others being history of hypertension and hemorrhagic stroke type.

CONCLUSION

RLS, especially unilateral or asymmetrical, might frequently pre-exist in patients presenting with subcortical stroke. The common laterality may suggest an important predictive value for RLS, and may form an important point for future research.

The relationship among restless legs syndrome (Willis-Ekbom Disease), hypertension, cardiovascular disease, and cerebrovascular disease

Untreated sleep disorders may contribute to secondary causes of uncontrolled hypertension, cardiovascular disease (CVD), and stroke. Restless legs syndrome, or Willis–Ekbom Disease (RLS/WED), is a common sensorimotor disorder with a circadian rhythmicity defined by an uncontrollable urge to move the legs that worsens during periods of inactivity or at rest in the evening, often resulting in sleep disruptions. Sleep disorders such as insomnia and obstructive sleep apnea (OSA) are established risk factors for increased risk of hypertension and vascular diseases. This literature review outlines the lessons learned from studies demonstrating insomnia and OSA as risk factors for hypertension and vascular diseases to support the epidemiologic and physiologic evidence suggesting a similar increase in hypertension and vascular disease risk due to RLS. Understanding the relationships between RLS and hypertension, CVD, and stroke has important implications for reducing the risks associated with these diseases.

Sleep-related problems in neurologic diseases

There is a strong association between sleep-related problems and neurologic diseases. Neurologic diseases of the CNS can directly cause sleep problems when sleep-wake mechanisms associated with the ascending reticular activating system are involved. The major sleep disorders associated with neurologic problems are outlined in the International Classification of Sleep Disorders, 2nd edition, as hypersomnias of central origin, sleep-related breathing disorders, the insomnias, circadian rhythm sleep disorders, sleep-related movement disorders, parasomnias, and sleep-related epilepsy. In a patient with CNS disease and excessive sleepiness, sleep-related breathing disorders should be a first concern, given the known association between obstructive sleep apnea (OSA) and cerebrovascular disease and the potential confounding effects that OSA might have on an otherwise compromised ischemic CNS penumbra. A basic knowledge of the anatomy and physiology of the sleep-wake mechanisms provides a rationale for pharmacologic intervention. Nonpharmacologic treatments are also important, especially when sleep-related breathing disorders are a concern. In addition, as patients with neurologic diseases are often prone to the adverse effects of many medications, the specific treatment regimen for any given individual should always include good sleep hygiene practices that use cognitive behavioral therapy.

A comparison of gray matter density in restless legs syndrome patients and matched controls using voxel-based morphometry

BACKGROUND

Restless legs syndrome (RLS) is a common neurological disorder the pathophysiology of which is incompletely understood. Four studies have examined structural differences between the brains of RLS patients and healthy controls, using voxel-based morphometry (VBM). All 4 studies have provided different results.

METHODS

Optimized VBM was used to search for structural differences in gray matter density. Sixteen RLS patients naïve to dopaminergic drugs and 16 age- and sex-matched controls received structural T1-weighted MR scans. Structural data were analyzed using FSL-VBM.

RESULTS

No difference in gray matter density was detected between the two groups (voxel-wise significance: no significant voxels at P= .89 (whole brain Family Wise Error (FWE) corrected); no significant voxels at P < .05 (whole brain False Discovery Rate (FDR) corrected; smallest achievable FDR threshold .99).

CONCLUSION/DISCUSSION

The present study did not replicate (confirm) previous findings of structural brain changes in RLS, but instead supported the findings of a recent study showing a lack of gray matter alteration in an elderly RLS population. More specifically, the results do not support neuronal loss as an underlying disease mechanism in RLS. Potential limitations in the application of VBM are also discussed.

Management of sleep disorders in stroke

OPINION STATEMENT

Scientific studies have proven a very strong association between stroke and obstructive sleep apnea (OSA). The prevalence of OSA is very high in patients with acute stroke, and untreated OSA is a stroke risk factor. In the stroke patient population, symptoms of OSA may atypically appear as isolated insomnia, hypersomnia, a dysfunction of circadian rhythm, a parasomnia, or a sleep-related movement disorder. Thus, we believe that in patients with acute stroke, OSA should be addressed first, using full in-laboratory, attended polysomnography (PSG), before other specific sleep disorders are aggressively addressed with specific therapeutic interventions. When OSA is diagnosed, supportive techniques including the application of continuous positive airway pressure (CPAP) therapy, positional therapies, or both should be considered first-line treatments. If OSA is ruled out by PSG, the therapeutic emphasis for sleep-related complaints is routinely based on instituting good sleep hygiene practices and using cognitive behavioral techniques (cognitive therapies, sleep restriction, stimulus control, and progressive relaxation therapies) because patients with stroke may be prone to the adverse effects of many of the medications that are otherwise routinely prescribed for a variety of specific sleep disorders.

Poststroke restless legs syndrome and lesion location: anatomical considerations

Several case studies have reported on restless legs syndrome (RLS) associated with stroke. In this study, we investigated the prevalence and the lesion topography of poststroke RLS. There were 137 patients with ischemic stroke included in this study. The diagnosis of RLS was made 1 month after the index stroke using the criteria established by the International RLS Study Group. All patients enrolled underwent magnetic resonance imaging within 7 days of the onset of the stroke. The prevalence of stroke-related RLS was calculated, and the topography of the associated ischemic lesions was analyzed. Among 137 patients, 17 patients (12.4%) were diagnosed with RLS after a stroke. Stroke-related RLS was found in 10 out of 33 patients with a basal ganglia/corona radiata infarct (30.3%), 1 out of 8 patients with an internal capsular infarct (12.5%), and 1 out of 7 patients with a thalamic infarct (14.3%). In addition, one out of 54 with a cortical lesion with/without subcortical involvement (1.9%), and 4 out of 18 patients with a pontine lesion (22.2%) had RLS. The analysis of the lesions in the cortical and subcortical group showed only 1 patient in the cortical group had stroke-related RLS, whereas 16 in the subcortical group had stroke-related RLS. The results of this study suggest that lesions of the subcortical brain areas such as the pyramidal tract and the basal ganglia-brainstem axis, which are involved in motor functions and sleep-wake cycles, may lead to RLS symptoms in patients after an ischemic stroke.

Cerebral white matter alterations in idiopathic restless legs syndrome, as measured by diffusion tensor imaging

In search for the pathoanatomical correlate of the restless legs syndrome (RLS), various neuroimaging and electrophysiological techniques have demonstrated partly conflicting results of cortical, subcortical, brainstem, and spinal alterations. In a novel approach, the delineation of potential cerebral white matter tract disruption was investigated by application of quantitative whole brain-based diffusion tensor imaging (DTI) to a well characterized group of 45 patients with idiopathic RLS. The data of patients and 30 healthy controls were statistically compared including computation of regional fractional anisotropy (FA) as a quantitative marker of white matter integrity by use of the tensor imaging and fiber tracking software. In the patient group, multiple subcortical areas of significantly reduced FA were observed bihemispherically in close proximity to the primary and associate motor and somatosensory cortices, in the right-hemispheric thalamus (posterior ventral lateral nucleus), in motor projectional fibers and adjacent to the left anterior cingulum. Together with the results of a recent study by use of an MRI-based gray matter analysis, which localized RLS-associated changes in the sensorimotor cortices, these findings gave support to an altered subcortical network, with the major component of altered cerebral sensorimotor pathways, within a hodological concept of the RLS pathoanatomy.

Update of the pathophysiology of the restless-legs-syndrome

The Restless Legs Syndrome (RLS) is a heterogeneous disease. Symptomatic or secondary forms encompass iron deficiency, uremia, pregnancy, polyneuropathy, and other causes. The so-called idiopathic RLS syndrome preferentially affects patients with a younger onset before the age of 30. Here we summarize pathophysiological results along the anatomical route, beginning at the cortex and followed by the basal ganglia, thalamus, A11 neurones, substantia nigra, brainstem nuclei, and spinal cord. Genetic risk variants for RLS have recently been identified in two genes, one of them the homeobox gene MEIS1, known to be involved in embryonic development and variants in a second locus containing the genes encoding mitogen-activated protein kinase MAP2K5, and the transcription factor LBXCOR1. A third one, the BTBD9 gene with unknown function encodes a BTB(POZ) domain. Accordingly, new concepts on pathophysiology have to bridge conventional knowledge with possible consequences deriving from these findings. Furthermore, this may create a framework to help understand why dopamine, opioid, and some anticonvulsant therapies are effective in RLS patients.

Cortical grey matter alterations in idiopathic restless legs syndrome: An optimized voxel-based morphometry study

An impairment of central somatosensory processing is assumed in restless legs syndrome (RLS). Although functional neuroimaging in RLS gave evidence to the presence of widespread functional changes in various brain areas, structural changes at the cortical level were not reported to be RLS-associated to date. Here, an analysis of high-resolution three-dimensional magnetic resonance imaging (MRI) was performed in 63 patients with idiopathic RLS by use of optimized voxel-based morphometry, in order to investigate if cortical areas might be altered in volume at group level according to the phenomenology of RLS. The comparison of the RLS patients versus controls yielded significant regional decreases of gray matter volume at corrected P < 0.05 in the bihemispheric primary somatosensory cortex, which additionally extended into left-sided primary motor areas. All clusters correlated both with the severity of RLS symptoms and with disease duration. These results, for the first time, give in vivo evidence to structural neocortical gray matter alterations in RLS patients. The alterations in the sensorimotor cortices might add to the pathophysiological concepts of idiopathic RLS.