Restless legs syndrome and drug-induced akathisia in headache patients

Potential therapeutic benefit of spinal cord stimulation in restless legs syndrome: scoping review and mechanistic considerations

BACKGROUND

Restless legs syndrome (RLS) is a prevalent sensorimotor disorder that can dramatically impair sleep quality, daytime function, and quality of life. Although many patients benefit from standard pharmacological therapy, some patients suffer from insufficient treatment response or medication intolerance. Novel treatment approaches are therefore necessary.

OBJECTIVE

Given the overlap between RLS and pain syndromes in both pathophysiological mechanisms and certain treatment options, we aimed to perform a scoping review of the available evidence on spinal cord stimulation (SCS) for RLS and discuss potential mechanistic implications.

METHODS

We identified a total of 16 cases of patients with RLS who underwent SCS, all from case reports or case series.

DISCUSSION

The published evidence is insufficient to assess SCS efficacy in patients with RLS, but SCS remains a promising investigational therapy in RLS on the basis of its potential mitigatory effects in the central hyperexcitability of the sensorimotor cortex through neuromodulation of spinal, subcortical, and cortical areas. A call for further research in this field is presented, with suggestions for future directions and trial designs.

Pathophysiological Bases of Comorbidity in Migraine

Despite that it is commonly accepted that migraine is a disorder of the nervous system with a prominent genetic basis, it is comorbid with a plethora of medical conditions. Several studies have found bidirectional comorbidity between migraine and different disorders including neurological, psychiatric, cardio- and cerebrovascular, gastrointestinal, metaboloendocrine, and immunological conditions. Each of these has its own genetic load and shares some common characteristics with migraine. The bidirectional mechanisms that are likely to underlie this extensive comorbidity between migraine and other diseases are manifold. Comorbid pathologies can induce and promote thalamocortical network dysexcitability, multi-organ transient or persistent pro-inflammatory state, and disproportionate energetic needs in a variable combination, which in turn may be causative mechanisms of the activation of an ample defensive system with includes the trigeminovascular system in conjunction with the neuroendocrine hypothalamic system. This strategy is designed to maintain brain homeostasis by regulating homeostatic needs, such as normal subcortico-cortical excitability, energy balance, osmoregulation, and emotional response. In this light, the treatment of migraine should always involves a multidisciplinary approach, aimed at identifying and, if necessary, eliminating possible risk and comorbidity factors.

Prevalence of restless legs syndrome in individuals with migraine: a systematic review and meta-analysis of observational studies

OBJECTIVE

Recent studies have shown an association between migraine and restless legs syndrome (RLS), but RLS prevalence among individuals with migraine differs substantially across studies. The present work aimed to comprehensively assess available evidence to estimate RLS prevalence among individuals with migraine and non-migraine controls.

METHOD

Web of Science, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed databases were searched for observational and case-control studies of RLS prevalence among individuals with migraine. Eligible studies were meta-analyzed using Stata 12.0 software.

RESULTS

Pooled RLS prevalence in migraine was 19%, and the prevalence was lower in Asia (16%) than outside Asia (21%). Pooled RLS prevalence was 18.8% among individuals with migraine with aura, and 18.5% among individuals with migraine without aura; the RLS prevalence in migraine with aura (MA) was higher than that of migraine without aura (MO) (OR 1.17, 95%CI 1.01-1.34; p = 0.037). Pooled RLS prevalence in a case-control study was significantly higher among individuals with migraine (17.9%) than among non-migraine controls (7.1%) (OR 2.65, 95%CI 2.26-3.10; p < 0.001).

CONCLUSION

Our meta-analysis provides the first reliable pooled estimate of RLS prevalence among individuals with migraine, and it provides strong evidence that RLS risk is higher among individuals with migraine than among controls.

Prevalence of restless legs syndrome in migraine patients with and without aura: a cross-sectional, case-controlled study

BACKGROUND

Although the comorbidity of migraine and restless legs syndrome (RLS) has been well-documented, the association between RLS and migraine frequency has yet to be elucidated. The present study aims to evaluate the prevalence of RLS among individuals who experience low-frequency, high-frequency, or chronic migraine presenting with and without aura.

METHODS

We conducted a cross-sectional, case-controlled study involving 505 participants receiving outpatient headache treatment. Standardized questionnaires were administered to collect information on experiences of migraine, RLS, sleep quality, anxiety, depression, and demographics. Participants were categorized into low-frequency (1-8/month), high-frequency (9-14/month), and chronic (≥15/month) headache groups. RLS was diagnosed according to the criteria outlined by the International RLS Study Group (IRLSSG). The Pittsburgh Sleep Quality Index (PSQI) and Hospital Anxiety and Depression Scale (HADS) were used to assess sleep quality and identify symptoms of anxiety and depression. Associations between migraine frequency and RLS prevalence were investigated using multivariate linear and logistic regression.

RESULTS

Univariate analysis revealed an effect of migraine frequency on RLS prevalence (p = 0.026), though this effect did not persist following adjustment for baseline characteristics (p = 0.256). The trend was robust in patients whose migraines presented with auras (p _univariate = 0.002; p _multivariate = 0.043) but not in those without auras (p _univariate and p _multivariate > 0.05). Higher anxiety [odds ratio (OR) = 1.18, p = 0.019] and sleep disturbance (OR = 1.17, p = 0.023) scores were associated with higher RLS prevalence.

CONCLUSIONS

Higher migraine frequency correlates with a higher prevalence of RLS, particularly among patients with auras.

Comorbidity of Migraine and Restless Legs Syndrome—A Case-Control Study

In order to evaluate a possible association between migraine and restless legs syndrome (RLS), we performed a case-control study on the comorbidity of RLS and migraine. Patients with migraine ( n = 411) and 411 sex- and age-matched control subjects were included. Migraine was diagnosed according to International Headache Society criteria, RLS according to the criteria of the International Restless Legs Syndrome Study Group. Furthermore, all patients had to fill out a self-assessment test performance on depression [Beck's Depression Inventory (BDI)]. RLS frequency was significantly higher in migraine patients than in control subjects (17.3% vs. 5.6%, P < 0.001; odds ratio 3.5, confidence interval 2.2, 5.8). In our sample, there was no significant association between migraine and depression as defined by the BDI score (9.6% in migraine vs. 4.0% in control subjects, P = 0.190). Depression was, however, not significantly more frequent in migraine patients with RLS (13.6%) than in migraine patients without RLS (8.7%). In addition, migraine patients with RLS had a significantly higher BDI score. RLS features did not differ significantly between migraine patients with RLS and control subjects with RLS. There is an association between RLS and migraine and, in addition, a co-association with depression. The underlying mechanism, however, remains undetermined and might be related to a dysfunction of dopaminergic metabolism in migraine.

Restless legs syndrome in migraine patients: prevalence and severity

BACKGROUND AND PURPOSE

Our aim was to study not only the prevalence but more importantly the severity and the correlation between sleep quality and restless legs syndrome (RLS) in a large population of well-defined migraine patients as poor sleep presumably triggers migraine attacks.

METHODS

In a large cross-sectional and observational study, data on migraine and RLS were collected from 2385 migraine patients (according to the International Classification of Headache Disorders ICHD-IIIb) and 332 non-headache controls. RLS severity (International RLS Study Group severity scale) and sleep quality (Pittsburgh Sleep Quality Index) were assessed. Risk factors for RLS and RLS severity were calculated using multivariable-adjusted regression models.

RESULTS

Restless legs syndrome prevalence in migraine was higher than in controls (16.9% vs. 8.7%; multivariable-adjusted odds ratio 1.83; 95% confidence interval 1.18-2.86; P = 0.008) and more severe (adjusted severity score 14.5 ± 0.5 vs. 12.0 ± 1.1; P = 0.036). Poor sleepers were overrepresented amongst migraineurs (50.1% vs. 25.6%; P < 0.001). Poorer sleep quality was independently associated with RLS occurrence (odds ratio 1.08; P < 0.001) and RLS severity (P < 0.001) in migraine patients.

CONCLUSION

Restless legs syndrome is not only twice as prevalent but also more severe in migraine patients, and associated with decreased sleep quality.

Increased Risk of Restless Legs Syndrome in Patients With Migraine: A Nationwide Population-Based Cohort Study

Previous studies suggest that an association between restless legs syndrome (RLS) and migraine exists. However, population-based data are unavailable in Asian cohorts. Our study thus aims to evaluate the association between migraine and RLS in a nationwide, population-based cohort in Taiwan and to examine the effects of age, sex, migraine subtype, and comorbidities on RLS development.Data from the Taiwan National Health Insurance Research Database were used. Patients aged 20 years or older with newly diagnosed migraine from 2000 to 2008 were included; 23,641 patients with newly diagnosed migraine and 94,564 subjects without migraine were randomly selected and followed until RLS development, withdrawal from the National Health Insurance, or until the end of 2011. A multivariate Cox proportional hazards regression model was used to explore the risk of RLS in patients with migraine after adjustment for demographic characteristics and comorbidities.Both cohorts were followed for a mean of 7.38 years. After adjustment for covariates, the risk of RLS was 1.42-fold higher (95% confidence interval = 1.13-1.79) in the migraine cohort than in the nonmigraine cohort (7.19 versus 3.42 years per 10,000 person-years). The increased risk was more prominent in males in the migraine cohort (1.87-fold increased risk, 95% confidence interval 1.22-2.85). Neither comorbidity status nor migraine subtype influenced the RLS risk.This population-based study demonstrated that migraine is associated with an increased risk of RLS compared with those without migraine, particularly in male patients with migraine and regardless of the comorbidity status.

Migraine and restless legs syndrome are associated in adults under age fifty but not in adults over fifty: a population-based study

BACKGROUND

Recent studies have shown an association between migraine and restless legs syndrome (RLS). However, migraine prevalence peaks from the 20s to 40s whereas RLS prevalence peaks after the 50s. Despite this, reports on how migraine and RLS may be associated by age is limited. Therefore, the purpose of this study is to investigate the comorbidity between migraine and RLS according to age.

METHODS

We selected a stratified random population sample of Koreans aged 19 to 69 years and evaluated them with a 60-item semi-structured interview designed to identify RLS, headache type, and clinical characteristics of migraine. To assess the association between migraine and RLS according to age, we divided participants into 5 age groups (19-29, 30-39, 40-49, 50-59, and 60-69 years) and analysed each group.

RESULTS

Subjects with migraine showed an increased RLS prevalence in the 19-29 (Odds ratio [OR] = 6.6, 95 % confidence interval [CI] = 1.2-36.8) and 40-49 (OR = 6.7, 95 % CI = 1.5-33.5) age groups compared to non-headache controls but failed to showed a significant association in the 50-59 (OR = 1.1, 95 % CI = 0.2-5.6) and 60-69 (OR = 0.4, 95 % CI = 0.1-4.0) age groups. Migraineurs with 1-10 (12.5 %, OR = 2.0, 95 % CI = 1.3-3.2, p = 0.003) and >10 (12.5 %, OR = 2.5, 95 % CI = 1.0-5.6, p = 0.038) attacks per month showed an increased RLS prevalence compared to migraineurs with <1 attack per month (2.1 %). Subjects with non-migraine headaches showed an increased odds for RLS (OR = 1.8, 95 % CI = 1.3-2.7) compared to non-headache controls. There was no significant difference (9.1 % vs. 6.9 %, p = 0.339) in the RLS prevalence between migraineurs and non-migraine headache subjects.

CONCLUSIONS

Our results suggest that migraine and RLS are differently associated according to age.

Psychiatric disorders and sleep issues

Sleep issues are common in people with psychiatric disorders, and the interaction is complex. Sleep disorders, particularly insomnia, can precede and predispose to psychiatric disorders, can be comorbid with and exacerbate psychiatric disorders, and can occur as part of psychiatric disorders. Sleep disorders can mimic psychiatric disorders or result from medication given for psychiatric disorders. Impairment of sleep and of mental health may be different manifestations of the same underlying neurobiological processes. For the primary care physician, key tools include recognition of potential sleep effects of psychiatric medications and familiarity with treatment approaches for insomnia in depression and anxiety.

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.

Migraine and restless legs syndrome: a systematic review

BACKGROUND

Restless legs syndrome (RLS) is increasingly being reported as a comorbidity of migraine.

METHODS

We conducted a systematic review and meta-analysis of studies investigating RLS in headache/migraine and vice versa. We calculated the prevalence and 95% confidence intervals (CI) of RLS in headache/migraine, of headache/migraine in RLS and controls, and odds ratios (ORs) of the association between the conditions. We then determined pooled effect estimates for the associations.

RESULTS

We identified 24 studies. RLS prevalence in migraine ranged from 8.7% to 39.0% with no apparent differences based on gender and aura status. Prevalence among controls was compatible with the literature. Migraine prevalence in RLS ranged from 15.1% to 62.6%. We did not pool prevalence data because of high unexplained heterogeneity. High heterogeneity with respect to the association between any migraine and RLS could be explained by study design. Pooled analyses showed substantially higher effect estimates in case-control studies (pooled OR = 4.19, 95% CI 3.07-5.71; I (2) = 0.0%) than in cohort studies (pooled OR = 1.22, 95% CI 1.14-1.30; I (2) = 0.0%).

CONCLUSION

Our results support the concept of RLS as an important comorbidity of migraine. However, the degree of association appears to be strongly determined by study design. Potential effects by gender and aura status and the role of RLS in other headache disorders remain unclear.

Association between restless legs syndrome and migraine: a population-based study

BACKGROUND AND PURPOSE

A higher prevalence of restless legs syndrome (RLS) in migraineurs has been reported in clinical samples and in two large-scale clinical trials performed on healthcare workers but general population-based studies on this topic are lacking. The aim of this study was to assess the association between migraine and RLS in an Italian rural adult population-based setting.

METHODS

The presence of migraine and RLS was assessed via a computer-assisted personal interview and self-administered questionnaires according to current diagnostic criteria in 1567 participants of a preliminary phase of an adult population-based study performed in South Tyrol, Italy.

RESULTS

Migraineurs had an increased risk of having RLS also after adjustment for confounding factors such as age, sex, major depression, anxiety and sleep quality (odds ratio 1.79; confidence interval 1.00-3.19; P = 0.049). This association was not modified by aura status and possible causes of secondary RLS. RLS was not significantly associated with tension-type headache.

CONCLUSIONS

Restless legs syndrome and migraine were associated in our rural adult population. This association could be explained by a possible shared pathogenic pathway which would implicate new management strategies of these two disorders.

The prevalence of migraine in restless legs syndrome

OBJECTIVE

While previous studies have investigated the prevalence of restless legs syndrome (RLS) in patients with migraine, we aimed to explore the prevalence and characteristics of migraine in adult patients diagnosed with RLS.

BACKGROUNDS

The association of primary headaches, especially of migraine, with RLS has recently attracted much attention. Migraine prevalence was reported to be higher in patients with RLS than in the general population, and the role of dopamine was strengthened.

METHODS

We evaluated 265 consecutive adult RLS patients (137 males and 128 females) followed up in a Sleep Disorders Unit and diagnosed according to criteria defined by the International Restless Legs Syndrome Study Group (IRLSSG). RLS characteristics, and the severity, were performed by using the IRLSSG severity scale. The diagnosis of headache subtypes was defined by the International Classification of Headache Disorders. Gender, age, age at RLS onset, duration of RLS, family history of RLS, family history of headache, presence of depression, any treatments given for RLS, and the change in headache following RLS treatment were questioned.

RESULTS

The mean age of the study population was 50.4 ± 12.8 years, mean age at RLS onset was 41.6 ± 13.2 years, and mean disease duration was 8.40 ± 8.6 years. Of these, 163 patients had headache; 40 of them were diagnosed to have migraine-type headache (15.1%). The presence of migraine-type headache was 9.4% in males with RLS, and 21.1% in female RLS patients. In RLS patients with migraine, 67.5% were females, while 48.0% of RLS patients with other types of headache were females (P = .032), and only 41.2% of RLS patients without headache were females (P = .005). The severity of RLS was significantly higher in patients with migraine compared with those without headache (P < .001). The presence of depression, the family history of RLS, and headache were also higher in patients with migraine compared with RLS patients with other types of headache or those without headache. Thirty-six patients with headache reported partial or substantial benefit from RLS treatment.

CONCLUSIONS

Our results did not suggest higher rates of migraine-type headache in RLS patients when compared with population-based prevalence studies from Turkey. Alternatively, the severity of RLS was significantly higher in patients with migraine. Although the increase in these scores does not constitute a relationship etiopathogenetic, it suggests a correlation between the type cross-model nociceptive systems. Moreover, the family history of RLS was higher in patients with migraine. The prevalence of migraine in patients with RLS, however, waits to be better demonstrated.

Comorbidity of Migraine

Migraine is a common neurological disorder and can be severely disabling during attacks. The highest prevalence occurs between the ages of 25 and 55 years. Prior studies have found that migraine occurs together with other illnesses at a greater coincidental rate than is seen in the general population. These occurrences are called "comorbidities". To delineate the comorbidities of migraine is important, because it can help improve treatment strategies and the understanding of the possible pathophysiology of migraine.

Restless legs syndrome induced by quetiapine: report of seven cases and review of the literature

We report on seven cases of restless legs syndrome (RLS) in patients treated with quetiapine. Small doses (50-250 mg at bedtime) provoked RLS in a dose-dependent way. Most patients suffered from an affective disorder and all were treated concomitantly with antidepressants. A search of the literature revealed a further nine cases of RLS concerning quetiapine, also afflicting only patients with affective disorders. Quetiapine seems to carry a special risk for RLS in this sort of patient. Possible causes for this concurrence are discussed.

Migraine and restless legs syndrome in women

BACKGROUND

Few clinic-based studies report an association between migraine and restless legs syndrome (RLS); however, population-based data are unavailable.

METHODS

Cohort study among 31,370 women participating in the Women's Health Study. We had detailed self-reported information on migraine, including aura status, and RLS. RLS was ascertained at the 9-year follow-up. We calculated odds ratios (OR) and 95% confidence intervals (CI) for the association between migraine and RLS. We investigated any indication of migraine until RLS ascertainment as well as migraine with and without aura at baseline, prior migraine before baseline, and new reports of migraine during follow-up.

RESULTS

At baseline or during follow-up 6857 (21.9%) women reported any migraine. These women had an increased risk for RLS (multivariable-adjusted OR = 1.22; 95%CI 1.13-1.32). Further analyses indicated a similar association for migraine with aura (multivariable-adjusted OR = 1.27; 95%CI 1.10-1.48) and migraine without aura (multivariable-adjusted OR = 1.24; 95%CI 1.09-1.40) as well as for new reports of migraine during follow-up (multivariable-adjusted OR = 1.30; 95%CI 1.10-1.54). Prior migraine did not appear to be associated with RLS.

CONCLUSIONS

Our data suggest an association between migraine and RLS at the population level. The association is similar for migraine with and without aura and for new reports of migraine during follow-up.

Migraine and restless legs syndrome: is there an association?

Occasional clinical reports have suggested a link between migraine and restless legs syndrome. We undertook a systematic review of the evidence, which supports this association, and consider possible shared pathogenic mechanisms and the implications for current clinical practice.

Comorbidities of migraine

Migraine is a common neurological disorder and can be severely disabling during attacks. The highest prevalence occurs between the ages of 25 and 55 years, potentially the most productive period of life. Migraine leads to a burden not only for the individual, but also for the family and society in general. Prior studies have found that migraine occurs together with other illnesses at a greater coincidental rate than is seen in the general population. These occurrences are called “comorbidities,” which means that these disorders are interrelated with migraine. To delineate the comorbidities of migraine is important, because it can help improve treatment strategies and the understanding of the possible pathophysiology of migraine. The comorbid illnesses in patients with migraine include stroke, sub-clinical vascular brain lesions, coronary heart disease, hypertension, patent foramen ovale, psychiatric diseases (depression, anxiety, bipolar disorder, panic disorder, and suicide), restless legs syndrome, epilepsy and asthma. In this paper, we review the existing epidemiological and hospital-based studies, and illustrate the connections between these illnesses and migraine.

Restless legs syndrome: pathophysiology, diagnosis and treatment

Restless legs syndrome (RLS) is clinically defined by the presence of (i) an urge to move the legs with or without an actual paraesthesia; (ii) a worsening of symptoms with inactivity; (iii) improvement with activity; and (iv) a worsening of symptoms in the evening and at night. Patients may use a variety of semantic phrases to describe their symptoms but all must have an urge to move. Most people with RLS also have periodic limb movements during sleep, although this is not part of the clinical diagnostic criteria. RLS is very common. About 10% of all Caucasian populations have RLS, although it may be mild in the majority of cases. Women generally outnumber men by about 2:1. As a general rule, RLS severity worsens through the first seven to eight decades of life, but may actually lessen in old age. The aetiology of RLS is only partly understood. There is a strong genetic component, and several genetic linkages and three causative genes have been identified worldwide. Several medical conditions, including renal failure, systemic iron deficiency and pregnancy, and possibly neuropathy, essential tremor and some genetic ataxias, are also associated with high rates of RLS. In all cases to date, the actual CNS pathology of RLS demonstrates reduced iron stores, in a pattern that suggests that the homeostatic control of iron is altered, not just that there is not enough iron entering the brain. The relationship between reduced CNS iron levels and the clinical phenotype or treatment response to dopaminergics is not known but generates promising speculation. Treatment of RLS is usually rewarding. Most patients respond robustly to dopamine receptor agonists. Over time, response may lessen, or the patients may develop 'augmentation', whereby they have a worsening of symptoms, usually in the form of an earlier onset. Other treatment options include gabapentin, or similar antiepileptic drugs, and opioids. High-dose intravenous iron is a promising but still experimental approach.

Burning mouth syndrome responsive to pramipexol

Burning mouth syndrome (BMS) is characterized by burning discomfort or pain in otherwise normal oral mucosa. It is usually refractory. Treatment modalities are scarce. Herein we report one case of primary disabling BMS, previously refractory to multiple regimens, with complete and persistent improvement with pramipexol, a nonergot dopamine agonist which has high selectivity for dopaminergic D2 receptors. We discuss potential pathophysiological implications of our findings.

Fibromyalgia and Overlapping Disorders: The Unifying Concept of Central Sensitivity Syndromes

OBJECTIVES

To discuss fibromyalgia syndrome (FMS) and overlapping conditions, eg, irritable bowel syndrome, headaches, and chronic fatigue syndrome, within the concept of central sensitivity syndromes (CSS).

METHODS

A critical overview of the literature and incorporation of the author's own views.

RESULTS

The concept of CSS seems viable. It is based on mutual associations among the CSS conditions as well as the evidence for central sensitization (CS) among several CSS members. However, such evidence is weak or not available in other members at this time, requiring further studies. The biology of CSS is based on neuroendocrine aberrations, including CS, that interact with psychosocial factors to cause a number of symptoms.

CONCLUSIONS

CSS is an important new concept that embraces the biopsychosocial model of disease. Further critical studies are warranted to fully test this concept. However, it seems to have important significance for new directions for research and patient care involving physician and patient education. Each patient, irrespective of diagnosis, should be treated as an individual considering both the biological and psychosocial contributions to his or her symptoms and suffering.

In restless legs syndrome, during changes in vigilance, the forced EEG shifts from alpha activity to delta or high alpha may lead to the altered states of dopamine receptor function and the symptoms

RLS cases may carry a genetic vulnerability called EEG alpha activity gate dyscontrols which appear during changes in vigilance and generally during sleep. It is triggered by forced EEG shifts either from alpha activity to delta or high alpha. Expressions of alpha activity gate dyscontrols may have a gate effect that trigger a second vulnerability-dopamine receptor specific individual sensitivity (DRSIS) and this leads to a deficiency in dopamine transmissions at diencephalospinal dopamine system (DSDS). Due to altered gene expressions in states of dopamine receptor function, DRSIS EEGs and RLS symptoms may be interpreted as follows: A. Disinhibition state is alpha activity gate dyscontrols induced inhibition of DSDS inhibitory dopamine modulations. Dopaminergic disinhibitions inhibit inhibitory interneurons of sensory and motor nuclei neurons that are involved in RLS. These sleep sensitive inhibitory interneurons possibly have GABA-ergic functions in sleep. (I) DSDS thalamic neurons' disinhibitory effects in thalamus on GABA-ergic interneurons of: (a) Intralaminar nuclei non-discriminative sensation neurons at thalamocortical premotor network leading to symptom of "a sense of urgency to move" generally referenced to legs.(b) Reticular thalamic nucleus (RTN) neurons. At polysomnography,during NREM sleep, disinhibited RTN neurons show alpha activity gate dyscontrol 1. These are recurrent subtypes of CAP in alpha band (7-12 Hz) pointing a difficulty in shifting to subtypes of CAP in low delta bands (0.25-2.5 Hz) and sleep fragmentations.(II) Supraspinal disinhibitory projections from DSDS thalamic neurons on GABA-ergic interneurons of: (a) Sensory neurons at posterior horns of spinal cord leading to dysesthesias, generally referenced to legs.(b) Medullary-reticulospinal neurons and by way of independent spinal rhythm generators on motoneurons leading to periodic limb movements in sleep.B. Activation state is an increase in symptoms. Sensory intralaminar and motor pontin nuclei neurons are in fact excitatory but are disinhibited in RLS. Due to altered gene expression, these neurons begin to perceive 'disinhibition' as reduced inhibition. Their glutamate receptors may activate deficient dopamine transmissions on RTN leading to alpha activity gate dyscontrol 2. This implies a failure in preventing shifts to frequent subtypes of CAP in high alpha and low beta bands (12-13 Hz) resulting in an increase of sensorimotor symptoms and appearance of motor restlessness, behavioral arousals and insomnia. C. Inhibition state is spontaneous relief from sensorimotor symptoms. Short or long-term synaptic plasticities of dopamine receptors towards activations initiate negative feedbacks from inhibitory interneurons. They are supported by inhibitory dopamine modulations- alertness and some awareness generally with regular high alpha EEGs, supraspinal inhibitions and a reverse movement pattern of PLMS during standing up and continuing to walk.

Augmentation as a treatment complication of restless legs syndrome: Concept and management

Augmentation constitutes the main complication of long-term dopaminergic treatment in restless legs syndrome (RLS). Although this condition was first described in 1996, and is characterized by an overall increase in severity of RLS symptoms (including earlier onset of symptoms during the day, faster onset of symptoms when at rest, expansion to the upper limbs and trunk, and shorter duration of the treatment effect), precise diagnostic criteria were not established until 2003. These criteria have recently been updated to form a new definition of augmentation based on multicentric studies. The present article reviews our current knowledge on clinical diagnosis, evaluation, pathophysiology, and treatment recommendations for this condition.

Possible joint origin of restless leg syndrome (RLS) and migraine

Sleep disorders have been described in migraine patients. Among sleep disorders RLS has been reported in up to one-third of migraineurs. Adverse effects of anti migraine therapy by dopamine antagonists can not fully explain this association. Therefore we present the hypothesis that RLS and migraine may have a joint origin. The hypothesis is supported by: (1) the same genetic origin for migraine without aura and RLS in single Italian family on chromosome 14q21; this gene codes survival motor neuron-interacting protein 1 (SIP1) which can play role in both diseases. (2) Correlation of both RLS and migraine with fibromyalgia. (3) Alteration of cortical excitability in both migraine and RLS.