Increased prevalence of nocturnal smoking in restless legs syndrome (RLS)

ObjectiveWe investigated the prevalence of nocturnal smoking (NS) in patients with RLS.MethodsOne hundred RLS patients living in Emilia-Romagna (Northern Italy) and 100 matched controls, randomly selected from the general population, underwent interviews for the presence of nocturnal smoking and for obsessive-compulsive traits, depression, excessive daytime sleepiness (EDS) and subjective sleep quality.ResultsNS was more prevalent in RLS patients than controls (lifetime prevalence: 12% vs. 2%, P = 0.012). Patients with NS had more frequently Sleep-Related Eating Disorders (SRED) than patients without NS (83.3% vs. 26.1%, P = 0.0002). Pathological and borderline Maudsley Obsessive-Compulsive Inventory (MOCI) values as well as pathological values at the Beck Depression Inventory (BDI) increased from controls to RLS patients without NS to RLS patients with NS (P = 0.005 and P = 0.01, respectively).ConclusionsWe demonstrate an increased prevalence of NS in patients with RLS, in many cases associated with increased SRED. NS may be associated with psychopathological traits in RLS and may be relevant in the management of RLS patients.     

Autonomic complaints in patients with restless legs syndrome

BackgroundData regarding autonomic function in restless legs syndrome (RLS) are limited to heart rate and blood pressure changes in cases with periodic limb movements (PLMS).MethodsWe compared autonomic symptoms of 49 subjects with RLS vs 291 control subjects using the Scales for Outcome in Parkinson disease-Autonomic (SCOPA-AUT) questionnaire, consisting of 23 items in six domains scored from 0 to 3. The total score and domain scores were transformed to 0–100 points. Subjects with neurodegenerative disorders (i.e., dementia, Parkinsonism) were excluded.ResultsThe RLS group was younger (mean ± standard deviation, 77.9 ± 8.0 vs 80.5 ± 7.9 years; P = .03) and included more women (84% vs 69%; P = .04). The mean SCOPA-AUT total score was higher in the RLS group compared with the control group (20 ± 11 vs 16 ± 9; P = .005). Additionally the RLS group had abnormalities in gastrointestinal, cardiovascular, and pupillomotor domains. When comparing the percentage of subjects with any complaint on individual questions (score of ⩾1), the RLS group had a greater number of subjects with sialorrhea, constipation, early abdominal fullness, lightheadedness when standing, and heat intolerance.ConclusionsAutonomic complaints, especially gastrointestinal, cardiovascular, and oversensitivity to light, were significantly increased in subjects with RLS. Causes for autonomic dysfunction in RLS require further investigation.     

The severity range of restless legs syndrome (RLS) and augmentation in a prospective patient cohort: Association with ferritin levels

ObjectivesThe aim of the study was to prospectively examine all patients with a diagnosis of RLS consulting a sleep disorders clinic and to assess RLS severity and augmentation and their associations, including ferritin levels.MethodsPatients were stratified into patients with RLS as ancillary diagnosis, RLS sufferers without current augmentation and RLS sufferers with current augmentation. Work-up included RLS severity scales and blood biochemical variables including indices of iron metabolism.ResultsIn an 18-month period, 302 patients with RLS (183 women, 119 men; mean age, 59.1 ± 13.7 years) were recruited. RLS was considered idiopathic in 291 patients (96.4%). Most patients (240, 79.5%) were RLS sufferers, whereas the remaining 62 (20.5%) had RLS as ancillary diagnosis. Nineteen out of 162 patients treated with dopaminergic agents (11.7%) had current augmentation. Almost one-third of all patients (31.1%) had ferritin levels <50 μg/l. Patients with an ancillary diagnosis of RLS had higher ferritin levels than RLS sufferers without current augmentation. The lowest ferritin levels were present in RLS sufferers with current augmentation 132.8 ± 98.0 μg/l vs. 100.6 ± 84.5 μg/l vs. 55.8 ± 43.6 μg/l; p = 0.002). Patients with augmentation did not differ from non-augmented patients regarding age, gender, RLS etiology, presence of previous augmentation, or any other documented comorbidity (p > 0.05).ConclusionThe severity spectrum of RLS in this clinical cohort ranged from the ancillary diagnosis of RLS to augmented RLS. There was an inverse correlation between RLS severity and ferritin levels. Patients with current augmentation had the lowest ferritin levels. Our data further strengthen a putative role of low iron stores as a potential aggravator of idiopathic RLS. Moreover, low ferritin might represent a potential biomarker of RLS augmentation under dopaminergic therapy.     

Pregnancy accounts for most of the gender difference in prevalence of familial RLS

ObjectiveThis study was designed to evaluate the associated risk of RLS with pregnancy in relation to the family history and the age of symptom onset of RLS.Methods and subjectsData from a prior RLS family history study in which 1019 subjects (527 males, 492 females) were interviewed, provided a diagnosis and characterization of RLS and determination of pregnancy status on which the current study analysis was undertaken.ResultsIn the family members of RLS probands, the prevalence of RLS was significantly higher for parous women than for nulliparous women (49.5% vs. 33.7%, OR = 1.92, 95% CI = 1.16–3.19) or for men (49.5% vs. 30.0%, OR 2.29, 1.69–3.10), but no different for nulliparous women compared to men (33.7% vs. 30.0%, OR 1.19, 0.72–1.96). When only those whose RLS started at or after age 30 were considered, similar differences occurred. These differences were not observed among family members of control probands.ConclusionsThese data indicate pregnancy has a major impact on the risk of developing RLS for those with a family history of RLS. This pregnancy effect appears to account for most of the gender differences often reported in overall RLS prevalence data.     

Nocturnal eating is part of the clinical spectrum of restless legs syndrome and an underestimated risk factor for increased body mass index

ObjectivesWe aimed to investigate the prevalence of night eating syndrome (NES) in a large cohort of patients with restless legs syndrome (RLS).MethodsOur cross-sectional study included 120 patients examined at the University of Bologna Centre for Sleep Disorders, Bologna, Italy, and met all four International RLS criteria for the diagnosis of RLS. Each patient underwent a semistructured telephone interview investigating demographic data and general health status, RLS features and severity, presence of excessive daytime sleepiness, and presence of NES.ResultsThe sample included 37 men and 83 women with a mean age of 63.8 ± 11.5 years. There were 31% of patients who reported episodes of nocturnal eating (NE); among them, 17% fulfilled the new diagnostic criteria for NES. Comparing RLS patients with and without NE, there were no differences in RLS features. However, RLS patients with NE were older (67.2 ± 11.6 vs 62.4 ± 11; P = .038), were in a higher body mass index (BMI) range (27.7 ± 3.8 vs 26.1 ± 4.1 kg/m²; P = .023), were taking more drugs for concomitant diseases (89% vs 72%; P = .031), were more likely to report insomnia (40% vs 23%; P = .041), and were using more hypnotic agents (37.8% vs 19.3%; P = .050) and dopaminergic drugs (65% vs 46%; P = .041). When comparing those RLS patients with NES diagnostic criteria and those without NES, no differences emerged in demographic, clinical, and RLS features; however, NES patients were in a higher BMI range (28.3 ± 4.1 vs 26.2 ± 3.9 kg/m², P = .037), were more frequently smokers (43% vs 17%; P = .027), and were more frequently using hypnotic agents (30% vs 24%; P = .025). Lastly, no differences were found when comparing patients with a NES diagnosis and those with NE not fitting the diagnostic criteria for NES, except for a higher use of benzodiazepine drugs (BDZ) in this latter subgroup (29% vs zero; P = .014).ConclusionsA nocturnal compulsion to eat seems to be an intrinsic part of the clinical spectrum of RLS manifestations and an odd risk factor for increases in BMI in RLS patients. However, it is still not clear if NE in RLS would fit in one of the two known categorized syndromes of NE (i.e., sleep-related eating disorder [SRED] or NES) or if it represents a different strictly RLS-related eating behavior.     

Prevalence of restless legs syndrome in patients with chronic pain in Maputo,Mozambique

ObjectivesBecause there is only one study to our knowledge on the prevalence of restless legs syndrome (RLS) in sub-Saharan Africa and RLS is more common in patients with some pain syndromes, we aimed to determine the prevalence of RLS in a population with chronic pain in Maputo, Mozambique.MethodsOur study was conducted in the Pain Unit of the Central Hospital of Maputo, Mozambique. Patients were individually interviewed by a neurologist, and only those fulfilling the criteria were included. After collection of demographic data and pain features, the patients answered the screening questions regarding RLS.ResultsA total of 123 patients with pain were interviewed. Five individuals were excluded. RLS was found in eight (6.77%) of 118 patients. The mean age of the eight patients with RLS was 54.6 years. Five patients (62.5%) were women and six (75%) were black individuals. Seven (87.5%) patients were diagnosed with neuropathic pain; one of them had AIDS and another one (12.5%) had orthopedic pain. The presence of hypertension and neuropathies was more frequent in the RLS group.ConclusionDespite the secondary causes involved, we believe that it is relevant to report the RLS prevalence detected in our study.     

Restless legs syndrome in end-stage renal disease: Clinical characteristics and associated comorbidities

BackgroundDespite being frequently described in patients with end-stage renal disease (ESRD), clinical characteristics and comorbidities in association with restless legs syndrome (RLS) are still to be confirmed.ObjectivesThe aim of this study was to investigate clinical factors associated with RLS in ESRD patients in hemodialysis.MethodsThis is a cross-sectional study of 400 patients on hemodialysis, evaluating RLS, clinical features and other sleep abnormalities.ResultsOut of 400, 86 patients presented RLS (21.5%; mean age 48.8 ± 13.8 y), being more frequent in females (p < 0.005). Forty-eight individuals (12% mean age 50.7 ± 13.1 y) had moderate/severe RLS, 14 reported symptoms prior to hemodialysis, 13 described family history of RLS, and eight described symptoms as disturbing during dialysis. RLS cases showed lower hemoglobin (p < 0.005), poorer quality of sleep (Pittsburgh Sleep Quality Index >5, p = 0.002), higher scores on the Beck Depression Inventory Scale (p < 0.005), greater scores on the Charlson Comorbidity Index (p = 0.01) and the Epworth Sleepiness Scale (p = 0.001) and higher risk of obstructive sleep apnea (OSA; Berlin questionnaire, p = 0.01). Hypertension was more frequent in cases with moderate/severe RLS (p = 0.01) and remained after controlling for the risk of OSA (p = 0.02).ConclusionIn ESRD patients in hemodialysis, RLS is present in 21.5%; 16% report symptoms prior to hemodialysis and a family history of RLS. Symptoms are disturbing during hemodialysis in 9% of cases. RLS is associated with lower hemoglobin, worse sleep quality, excessive daytime sleepiness, depressive symptoms and higher risk of OSA. Hypertension is associated with moderate/severe RLS.     

Blood pressure changes associated with periodic leg movements during sleep in healthy subjects

Background and objectivesPeriodic leg movements during sleep (PLMS) are associated with important blood pressure (BP) increases in restless legs syndrome (RLS) patients. These movements also are highly prevalent in the healthy elderly population. The aims of our study were to evaluate if heart rate (HR) and BP changes associated with PLMS are present in healthy subjects with no report of health concerns and to compare the amplitude of cardiovascular changes in healthy subjects to that of RLS subjects.MethodsFourteen healthy subjects (six men, eight women; 46.6 ± 9.7 y) and 14 RLS subjects (six men, eight women; 47.6 ± 11.8 y) matched for age and gender participated in our study. Beat-to-beat noninvasive BP was continuously recorded during one night of polysomnography. HR, systolic BP (SBP) and diastolic BP (DBP) were measured for 10 beats before and 15 beats after onset of PLMS with and without microarousals (MA).ResultsPLMS were associated with sudden and significant increases of HR, SBP and DBP in both groups; however, cardiovascular increases were more pronounced in RLS subjects than in healthy subjects.ConclusionsBecause PLMS index increases with age in healthy subjects and aging is associated with higher cardiovascular risk, further studies should investigate the impact of PLMS-related BP changes on the development of cardiovascular diseases in healthy elderly populations.     

Voxel-based morphometry in unmedicated patients with restless legs syndrome

BackgroundThe pathophysiology of restless legs syndrome (RLS) is not yet understood. A prior voxel-based morphometry (VBM) study reported gray matter increase in the pulvinar of the thalamus in a group of patients, most of whom were on medical treatment. Since there is evidence that medication can change the volume of cerebral structures, the question arises as to whether the reported morphometric alterations are caused by the RLS itself or, alternatively, are a consequence of drug treatment. To address this issue, we performed VBM in unmedicated RLS patients.MethodsFourteen patients with idiopathic RLS with no (n = 11) or only minimal (n = 3) treatment exposure in the past and 14 age- and sex-matched healthy subjects were investigated. All subjects were free of psychotropic drugs for at least 4 months. Morphological data were analyzed by using optimized VBM.ResultsWe did not detect any structural changes except for slightly increased gray matter density in the ventral hippocampus (p = 0.046 on the left and p = 0.055 on the right side) and in the middle orbitofrontal gyrus (p = 0.046 on the right and p = 0.097 on the left side).ConclusionOur study could not confirm the findings of a prior study. A possible explanation for the divergent findings is the difference between the populations examined. Since, in our study, essentially treatment-naïve patients were investigated, it is possible that the prior findings reflect treatment-induced effects on cerebral morphology in RLS.     

Assessing health-related quality of life in patients with restless legs syndrome in Korea: Comparison with other chronic medical diseases

BackgroundThere have been few quality of life (QoL) studies of patients with restless legs syndrome (RLS) in Asian countries. We studied the QoL of patients with RLS and compared it to normal controls and patients with hypertension, type 2 diabetes, or osteoarthritis in Korea.MethodsA total of 215 RLS patients (141 female; mean age 51.7 ± 13.5) were enrolled. All patients completed the questionnaires, including all the Korean versions of SF-36, RLS QoL, the International RLS Severity scale (IRLS), the Pittsburgh Sleep Quality Index (PSQI), and the Beck Depression Inventory-2 (BDI-2). These results were compared with the scores from normal controls (N = 214) and from patients with hypertension (196), uncomplicated type 2 diabetes (185), or osteoarthritis of the knee (177).ResultsThe SF-36 QoL in patients with RLS was lower than that of the normal controls, and even lower than patients with hypertension or diabetes, but higher than those with osteoarthritis. The SF-36 Qol of RLS patients showed a significantly negative correlation with the severity of RLS symptoms (r = ?0.430, p < 0.001) and the severity of depression (r = ?0.565, p < 0.001), but was not significantly related to gender, age, or age-of-symptom onset (early or late-onset). Step-wise multiple regression identified three factors related to SF-36 QoL: depression (46.5% of RLS had responses on BDI-2 indicating depression) (β = ?.899, p < 0.001), RLS symptom severity (K-IRLS) (β = ?.718, p < 0.001), and gender (female) (β = ?6.128, p = 0.007).ConclusionsThese findings show that RLS has a considerable impact on the QoL of Koreans, which is comparable with studies of western countries. The QoL impairment relates to the degree of depression with RLS for Koreans.     

Reliability and validity of two self-administered questionnaires for screening restless legs syndrome in population-based studies

BackgroundA reliable and valid questionnaire for screening restless legs syndrome (RLS) is essential for determining accurate estimates of disease frequency. In a 2002 NIH-sponsored workshop, experts suggested three mandatory questions for identifying RLS in epidemiologic studies. We evaluated the reliability and validity of this RLS-NIH questionnaire in a community-based sample and concurrently developed and evaluated the utility of an expanded screening questionnaire, the RLS-EXP.MethodsThe study was conducted at Kaiser Permanente of Northern California and the Stanford University Sleep Clinic. We evaluated test–retest reliability in a random sample of subjects with prior physician-assigned RLS (n = 87), subjects with conditions frequently misclassified as RLS (n = 31), and healthy subjects (n = 9). Validity of both instruments was evaluated in a random sample of 32 subjects, and in-person examination by two RLS specialists was used as the gold standard.ResultsFor the first three RLS-NIH questions, the kappa statistic for test–retest reliability ranged from 0.5 to 1.0, and sensitivity and specificity was 86% and 45%, respectively. For the subset of five questions on RLS-EXP that encompassed cardinal features for diagnosing RLS, kappas were 0.4–0.8, and sensitivity and specificity were 81% and 73%, respectively.ConclusionsSensitivity of RLS-NIH is good; however, the specificity of the instrument is poor when examined in a sample that over-represents subjects with conditions that are commonly misclassified as RLS. Specificity can be improved by including separate questions on cardinal features, as used in the RLS-EXP, and by including a few questions that identify RLS mimics, thereby reducing false positives.     

Nocturnal masseter muscle activity is related to symptoms and somatization in temporomandibular disorders

ObjectiveTemporomandibular disorders (TMD) have often been related to sleep bruxism and elevated nocturnal masseter muscle activity (NMMA). However, previous studies have revealed controversial results, and the role of somatization, depression and anxiety has not been studied in this context. The aim of this study was to investigate the association between NMMA and pain intensity, TMD related symptoms, somatoform symptoms, depression, and anxiety in chronic TMD.MethodsThirty-six subjects with chronic painful TMD, 34 subjects with pain free bruxism, and 36 healthy controls recorded their nocturnal masseter muscle activity during three consecutive nights with portable devices. In addition, participants completed pain diaries and questionnaires. Diagnoses were established using the research diagnostic criteria for TMD.ResultsSubjects with chronic TMD reported a reduced general health state (p < .001), higher levels of somatoform symptoms (p < .001), depression (p < .05), and anxiety (p < .001) compared to control subjects with or without sleep bruxism. The amount of NMMA did not differ significantly between the groups. In subjects with TMD, pain intensity was not related to NMMA. However, higher NMMA was related to higher intensity of jaw related symptoms such as headache or tinnitus, and higher somatization in general.ConclusionChronic TMD is associated with elevated levels of psychopathology. These findings suggest a common link between NMMA, somatization, and symptom intensity in chronic TMD.     

Is preeclampsia associated with restless legs syndrome?

ObjectiveRestless legs syndrome (RLS) is a common neurologic disorder. Secondary RLS includes pregnancy and iron deficiency. Prevalence of RLS in pregnancy ranges from 11% to 27%. We aimed to assess the frequency and characteristics of RLS in pregnancy in a Peruvian population and to evaluate the possible pregnancy or delivery complications due to RLS.MethodsWe assessed 218 consecutive expectant mothers at the inpatient clinic of the Hospital San Bartolome in Lima, Peru. Assessment was performed by using the standard diagnostic criteria for RLS and by using a clinical and diagnostic interview. Questionnaires for RLS severity, idiopathic RLS (IRLS), and excessive daytime sleepiness (EDS) according to the Epworth sleepiness scale (ESS) were used. Blood examination was performed for hemoglobin and hematocrit. For comparison, RLS patients were matched for age and body mass index (BMI) with pregnant women without RLS.ResultsOut of 218 patients, 40 (18.4%) fulfilled diagnostic criteria for RLS. In RLS patients, prophylactic iron supplementation therapy during pregnancy was less frequently taken (P = .02). Pregnant women with RLS had a higher ESS score than pregnant controls (10.6 +/− 3.1 vs 7.6. +/− 3.6; P < .001). Preeclampsia was more frequent in RLS (7/40 vs 1/39; P = .03).ConclusionsIn our study, RLS was frequent in pregnant Peruvian women, especially in those without prophylactic iron supplementation. RLS patients described more EDS. Preeclampsia was more common in RLS. Our study is the first study to indicate a possible association between RLS and preeclampsia.     

The efficacy of cognitive-behavioral therapy for insomnia in patients with chronic pain

Study objectivesTo assess the efficacy of cognitive-behavioral therapy for insomnia (CBT-I) in patients with non-malignant chronic pain.MethodsTwenty-eight subjects with chronic neck and back pain were stratified according to gender, age, and ethnicity, then assigned to one of the two treatment groups: CBT-I or a contact control condition.InterventionEight weeks of CBT-I including sleep restriction, stimulus control, sleep hygiene, and one session of cognitive therapy devoted to catastrophic thoughts about the consequences of insomnia.Measurements and resultsOutcomes included sleep diary assessments of sleep continuity, pre–post measures of insomnia severity (ISI), pain (Multidimensional Pain Inventory), and mood (BDI and POMS). Subjects receiving CBT-I (n = 19), as compared to control subjects (n = 9), exhibited significant decreases in sleep latency, wake after sleep onset, number of awakenings, and significant increase in sleep efficiency. The diary findings were paralleled by significant changes in the ISI (p = 0.05). Significant improvement (p = 0.03) was found on the Interference Scale of the Multidimensional Pain Inventory. The groups did not significantly differ on mood measures or measures of pain severity.ConclusionsCBT-I was successfully applied to patients experiencing chronic pain. Significant improvements were found in sleep as well as in the extent to which pain interfered with daily functioning. The observed effect sizes for the sleep outcomes appear comparable to or better than meta-analytic norms for subjects with Primary Insomnia.     

Clinical efficacy and safety of intravenous ferric carboxymaltose treatment of pediatric restless legs syndrome and periodic limb movement disorder

BackgroundIron supplementation is the most commonly considered treatment option for children with restless legs syndrome (RLS) or periodic limb movement disorder (PLMD); however, there is a scarcity of evidence on the effectiveness of intravenous preparations. In this study, we evaluated the effectiveness and tolerability of intravenous ferric carboxymaltose (IV FCM) on clinical symptoms and iron indices in children with RLS or PLMD.MethodsThis was a single-center retrospective data analysis. Children with a diagnosis of RLS or PLMD, who underwent a single infusion of IV FCM, were included. Clinical Global Impression (CGI) Scale scores, serum ferritin, and serum iron profile at baseline and after eight weeks post infusion were obtained. Adverse effects were assessed.ResultsThirty-nine children received IV FCM, 29 with RLS and 10 with PLMD. Pre-infusion CGI-Severity revealed moderate illness, with post-infusion CGI-Improvement between “very much improved” and “much improved”. Ferritin increased from 14.6 μg/L ± 7.01 to 112.4 μg/L ± 65.86 (p < 0.00001), together with improvements in iron, total iron binding capacity, and transferrin levels from baseline to post-treatment. When compared to children with RLS, those with PLMD had a similar improvement in clinical symptoms and laboratory parameters. Seven subjects (14.3%) experienced one or two adverse events; all were mild.ConclusionsChildren with RLS and PLMD responded to IV iron supplementation with improvement in both clinical severity and laboratory parameters. Treatment was well tolerated. Although larger, randomized-controlled trials are needed, IV FCM appears to be a promising alternative to oral iron supplementation for the treatment of pediatric RLS or PLMD.     

Prevalence of restless legs syndrome in a Japanese elderly population

ObjectiveTo estimate the prevalence of restless leg syndrome (RLS) in elderly Japanese people by means of a population-based survey of subjects aged ≥65 years.BackgroundStudies conducted worldwide have revealed large variations in the prevalence of RLS among different populations. However, few studies have been done in Japan.MethodsA population-based survey was carried out from 2003 to 2006 through a local healthcare project in the small town of Ajimu in a rural area of southern Japan. A Japanese translation of the questionnaire covering the four features of RLS as defined by the International RLS Study Group in 1995 was used to confirm the diagnosis of RLS. All participants aged ≥65 years were invited to fill out the questionnaire. Subjects with positive results underwent face-to-face interviews.ResultsA total of 1251 persons (men, 35%; mean age, 75.0 ± 6.1 years) answered the questionnaire. Of these 1251 participants, 70 (5.6%) (men, 20%; mean age, 75 ± 4.9 years) answered the questions on RLS positively. Face-to-face interviews and examination confirmed the diagnosis of RLS in 12 subjects. Therefore the overall prevalence of RLS in the elderly Japanese population was estimated at 0.96%, with a higher prevalence in women (1.23%) than in men (0.46%).ConclusionThe overall prevalence of RLS among inhabitants of Ajimu aged ≥65 years is 0.96%. Most of the subjects identified were women. The prevalence of RLS is lower in Japan than in studies conducted in European and North American populations.     

Effect of pain on the modulation in discharge rate of sternocleidomastoid motor units with force direction

ObjectiveTo compare the behavior of sternocleidomastoid motor units of patients with chronic neck pain and healthy controls.MethodsNine women (age, 40.4 ± 3.5 yr) with chronic neck pain and nine age- and gender-matched healthy controls participated. Surface and intramuscular EMG were recorded from the sternocleidomastoid muscle bilaterally as subjects performed isometric contractions of 10-s duration in the horizontal plane at a force of 15 N in eight directions (0–360°; 45° intervals) and isometric contractions at 15 and 30 N force with continuous change in force direction in the range 0–360°. Motor unit behavior was monitored during the 10-s contractions and the subsequent resting periods.ResultsThe mean motor unit discharge rate depended on the direction of force in the control subjects (P < 0.05) but not in the patients. Moreover, in three of the nine patients, but in none of the controls, single motor unit activity continued for 8.1 ± 6.1 s upon completion of the contraction. The surface EMG amplitude during the circular contraction at 15 N was greater for the patients (43.5 ± 54.2 μV) compared to controls (16.9 ± 14.9 μV; P < 0.05).ConclusionsThe modulation in discharge rate of individual motor units with force direction is reduced in the sternocleidomastoid muscle in patients with neck pain, with some patients showing prolonged motor unit activity when they were instructed to rest.SignificanceThese observations suggest that chronic neck pain affects the change in neural drive to muscles with force direction.     

Elevated C-reactive protein is associated with severe periodic leg movements of sleep in patients with restless legs syndrome

BackgroundRestless legs syndrome (RLS) is a common sleep disorder in which urges to move the legs are felt during rest, are felt at night, and are improved by leg movement. RLS has been implicated in the development of cardiovascular disease. Periodic leg movements (PLMs) may be a mediator of this relationship. We evaluated systemic inflammation and PLMs in RLS patients to further assess cardiovascular risk.Methods137 RLS patients had PLM measurements taken while unmedicated for RLS. Banked plasma was assayed for high sensitivity C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha).ResultsMean (SD) PLM index was 19.3 (22.0). PLMs were unrelated to TNF-a and IL-6, but were modestly correlated with log CRP (r(129) = 0.19, p = 0.03). Those patients with at least 45 PLMs/h had an odds ratio of 3.56 (95% CI 1.26–10.03, p = 0.02, df = 1) for having elevated CRP compared to those with fewer than 45 PLMs/h. After adjustment for age, race, gender, diabetes, hypertension, hyperlipidemia, inflammatory disorders, CRP-lowering medications, and body mass index, the OR for those with ?45 PLMs/h was 8.60 (95% CI 1.23 to 60.17, p = 0.03, df = 10).ConclusionsPLMs are associated with increased inflammation, such that those RLS patients with at least 45 PLMs/h had more than triple the odds of elevated CRP than those with fewer PLMs. Further investigation into PLMs and inflammation is warranted.