Elevated periodic limb movement index is associated with hypoxemia in children with early onset scoliosis.

PURPOSE: Patients with early onset scoliosis are at high risk of sleep disordered breathing, sleep disruption, and adverse consequences of poor sleep. In this study, we aim to assess the prevalence of periodic limb movements of sleep in a cohort of children with early onset scoliosis and identify factors that correlate with the presence of periodic limb movements. METHODS: This is a retrospective chart review of 40 patients with EOS (ages 1-17 years) who underwent a PSG from 2003 through 2019. Data collected included age, sex, and polysomnography parameters. Descriptive statistics were used: independent T test and Pearson correlation. RESULTS: The average age was 9.6 years (SD 5.2); 22 were female. Eleven patients (27.5%) had elevated periodic limb movement index (PLMI) (≥ 5). Those with PLMI ≥ 5 had arousal index of 15.4 (SD 7.2) and those with normal PLMI having an arousal index of 9.4 (SD 4.9); this reached statistical significance (p < 0.05). Those with elevated PLMI spent 4.9 (SD 8.3) minutes with saturations below 88%, while those with normal PLMI spent 1.0 (SD 1.8); this was statistically significant. There was a moderate positive correlation between arousal index, hypoxemia, and PLMI. CONCLUSION: The study suggests that children with early onset scoliosis have higher frequency of periodic limb movements during sleep, and these may be correlated with increased arousal and with hypoxemia.

Prevalence of periodic limb movement in sleep in people with epilepsy: A semi-structured literature review.

OBJECTIVES: Epilepsy is a prevalent health problem worldwide in all ages, and it is essential to identify disease markers for diagnosis and treatment. Periodic limb movements in sleep (PLMS) are a common finding in polysomnography (PSG). Still, its clinical relevance in people with epilepsy (PWE) is unknown. The aim of this review was to compare PLMS frequency in PWE and controls. METHODS: A semi-structured literature review was conducted using PubMed in search of relevant studies in English on August 23, 2019, with the search terms "sleep," "epilepsy," or "seizure," and "polysomnography" in the title and/or abstract. The research was complemented with citation analysis and manual search using Google Scholar. Studies involved PWE and comparative controls using PSG with reported PLMS index (PLMI). RESULTS: Seven studies were identified. Only two showed a statistically significant difference in PLMI between cases and controls, and in another study, cases had uncontrolled seizures. In general, studies did not adjust for potential confounders including demographics, apnea-hypopnea index, or medication use. CONCLUSIONS: We found few studies exploring the prevalence of PLMS in PWE. In the majority, PLMI did not differ from controls. Further studies are warranted given the prevalence of sleep disturbances in epilepsy.

Contemporary Concise Review 2020: Sleep.

Obstructive sleep apnoea (OSA) now affects one-seventh of the world's population. Treatment of even mild OSA can improve daytime sleepiness and quality of life. Recent modifications to uvulopalatopharyngoplasty may make it a more widely applicable treatment option in selected patients with OSA. Diet and exercise have effects on sleep apnoea severity independent of weight loss. Insomnia has become increasingly common during the coronavirus disease 2019 (COVID-19) pandemic.

Retrospective Analysis of Risk Factors for Periodic Limb Movements in a Large Cohort of Insomnia and Chronic Fatigue Patients.

INTRODUCTION: Although the pathophysiology of periodic limb movements in sleep (PLMS) is not well understood, there is increasing belief that management of PLMS can modulate humans' general health. The aim of this study is to investigate the associations between risk factors including the use of antidepressants, hypnotics, and antihistamines as well as of caffeine, alcohol, and nicotine and the occurrence of PLMS and periodic limb movement disorder (PLMD). METHODS: Patients with either chronic fatigue or insomnia who underwent polysomnography as standardized clinical assessment were included in a retrospective study. Associations were calculated between substance use and sleep variables. RESULTS: Tricyclic antidepressants and serotonin and norepinephrine reuptake inhibitor (SNRI) are significantly associated with higher rates of PLMS. Additionally, SNRI is significantly positive associated with PLMD, as also seen for selective serotonin reuptake inhibitors (SSRI). The most frequently used SSRI escitalopram was significantly positively associated with PLMS and PLMD. A significantly negative association was found between paroxetine and PLMS. Benzodiazepines are negatively associated with PLMS and PLMD. Sedative antidepressants, antihistamines, and substance use are not associated with PLMS nor PLMD in this study. DISCUSSION: This retrospective study adds supportive evidence to the association of drug classes with PLMS and PLMD. These findings may impact on clinical management of patients with a combined anxiety or mood disorder in need for these drug classes on the one hand and a significant sleep architecture disturbance through PLMS, potentially contributing to daytime symptoms, on the other hand.

Lack of Association between Periodic Limb Movements during Sleep and Neuroimaging Signatures of Cerebral Small Vessel Disease in Stroke-Free Community-Dwelling Older Adults. The Atahualpa Project.

BACKGROUND: Evidence of the relationship between periodic limb movements during sleep (PLMS) and cerebral small vessel disease (cSVD) is limited and inconsistent. Here, we aimed to assess the independent association between PLMS and the different neuroimaging signatures of cSVD. METHODS: Atahualpa residents aged more than or equal to 60 years enrolled in the Atahualpa Project undergoing polysomnography and MRI with time intervals less than or equal to 6 months were included. MRI readings focused on white matter hyperintensities (WMH) of presumed vascular origin, deep cerebral microbleeds (CMB), silent lacunar infarcts (LI), and more than 10 enlarged basal ganglia-perivascular spaces (BG-PVS). Data from single-night polysomnograms were interpreted according to recommendations of the American Academy of Sleep Medicine. Associations between the PLMS index and neuroimaging signatures of cSVD (as dependent variables) were assessed by means of logistic regression models, adjusted for relevant confounders. RESULTS: A total of 146 individuals (mean age: 71.4 ± 7.5 years; 64% women) were included. A PLMS index more than or equal to 15 per hour were noted in 48 (33%) participants. Moderate-to-severe WMH were present in 33 individuals (23%), deep CMB in 9 (6%), silent LI in 16 (11%), and more than 10 BG-PVS in 44 (30%). In univariate analyses, silent LI (P = .035) and the presence of more than 10 enlarged BG-PVS (P = .034) were significantly higher among participants with a PLMS index more than or equal to 15 per hour. However, fully-adjusted multivariate models showed no significant association between PLMS index more than or equal to 15 per hour and any of the neuroimaging signatures of cSVD. CONCLUSIONS: This study shows no independent association between the PLMS index and neuroimaging signatures of cSVD in stroke-free community-dwelling older adults.

Level of sleep disorders among patients with chronic obstructive pulmonary disease.

OBJECTIVE: To measure the level of sleep disorders among patients with chronic obstructive pulmonary disease, and to see if there was any difference in terms of demographic variables and socioeconomic status. METHODS: The cross-sectional descriptive observational study was conducted from March to June 2017, and data was collected through purposive sampling from different tertiary health care centres of Faisalabad, Pakistan. Sleep-50-Urdu scale was used to measure sleep disorders among patients with chronic obstructive pulmonary disease. SPSS 21 was used for data analysis. RESULTS: Of the 140 respondents 70(50%) each were males and females with an overall mean age of 48.64±17.39 years. The patients had significantly high level of narcolepsy (p<0.05), but those from high socioeconomic status had relatively lower level of narcolepsy (p<0.05). Male patients and people from lower socioeconomic status also suffered from sleep apnoea and insomnia along with chronic obstructive pulmonary disease (p<0.05). CONCLUSIONS: Narcolepsy along with sleep apnoea and insomnia were significantly more prevalent among chronic obstructive pulmonary disease patients from lower socioeconomic status.

Cerebrovascular Accident Risk in a Population with Periodic Limb Movements of Sleep: A Preliminary Meta-Analysis.

BACKGROUND AND PURPOSE: Periodic limb movements of sleep (PLMS) are usually comorbid with hypertension, tachycardia, and coronary arterial diseases, which are also risk factors for cerebrovascular accidents (CVA). However, evidence about the relationship between CVA and PLMS is still weak. The aim of this study was to investigate (1) the prevalence of CVA in patients with PLMS, and (2) the severity of PLMS in patients with or without CVA through a meta-analysis. METHODS: The electronic databases of PubMed, Embase, ScienceDirect, ClinicalKey, Cochrane Library, ProQuest, Web of Science, and ClinicalTrials.gov were searched. The inclusion criteria were (1) articles investigating comorbidity between PLMS and CVA, and (2) clinical trials in humans. RESULTS: This meta-analysis included (1) 9,823 patients with PLMS and 9,416 controls from 5 studies to analyze the prevalence of CVA in PLMS, and (2) 158 patients with PLMS with CVA and 88 PLMS controls without CVA from 3 studies to analyze the severity of PLMS with and without CVA. The results showed (1) significantly higher comorbidity rates of CVA in the patients with PLMS than in the controls without PLMS (OR 1.267, p = 0.019), and (2) higher PLM index in the patients with CVA than in the controls (Hedges' g = 0.860, p = 0.001; means difference: 4.435, p = 0.016). CONCLUSIONS: The results revealed (1) a worse severity of PLMS in the patients with CVA, and (2) increased prevalence of CVA in the patients with PLMS. Based on our results, the patients had a higher prevalence of CVA within 8 years of a diagnosis of PLMS compared to those without PLMS by about 1.3-fold. Whether (1) patients with PLMS receiving treatment have a similar incidence of stroke to those without PLMS, and (2) secondary stroke prevention can lower the severity of PLMS or whether those with severe PLMS have a higher risk of stroke is still inconclusive. Future studies investigating the prevalence of CVA in patients with PLMS should use a follow-up period of over 8 years.

Sleep-Related Leg Movements in Patients with Transient Ischemic Attack and Controls.

BACKGROUND: Periodic leg movements during sleep (PLMS) have been associated with an increased risk for cardiovascular diseases and there is a high prevalence of PLMS found in patients with obstructive sleep apnea syndrome (OSAS). We evaluated patients with transient ischemic attack (TIA) for PLMS and respiratory related leg movements (RRLM), versus a control group without TIA. METHODS: Twenty-five patients with TIA and 34 patients with no vascular diagnosis were referred for polysomnography. Diagnosis of PLMS was made if the periodic leg movement index (PLMI) was ≥5 and clinical significant as PLMI ≥15. RESULTS: There was no significant difference in PLMI ≥5 and ≥15 between patients with and without TIA. In the absence of OSAS, 2 out of 5 TIA patients (40%) had a PLMI ≥15 compared to 1 of the 19 patients without TIA (5%; p = 0.037). There was no increase in RRLMs when OSAS was present. CONCLUSIONS: TIA patients did not have higher PLMI compared to controls, and in the presence of OSAS, there was no increase in RRLMs compared to patients without TIA. In selective patients, PLMS could be associated with cardiovascular diseases, since PLMS was clinically more often found in the TIA group without OSAS.

Prevalence and determinants of periodic limb movements in the general population.

OBJECTIVE: Periodic limb movements during sleep (PLMS) are sleep phenomena characterized by periodic episodes of repetitive stereotyped limb movements. The aim of this study was to describe the prevalence and determinants of PLMS in a middle to older aged general population. METHODS: Data from 2,162 subjects (51.2% women, mean age = 58.4 ± 11.1 years) participating in a population-based study (HypnoLaus, Lausanne, Switzerland) were collected. Assessments included laboratory tests, sociodemographic data, personal and treatment history, and full polysomnography at home. PLMS index (PLMSI) was determined, and PLMSI > 15/h was considered as significant. RESULTS: Prevalence of PLMSI > 15/h was 28.6% (31.3% in men, 26% in women). Compared to subjects with PLMSI ≤ 15/h, subjects with PLMSI > 15/h were older (p < 0.001), were predominantly males (p = 0.007), had a higher proportion of restless legs syndrome (RLS; p < 0.001), had a higher body mass index (p = 0.001), and had a lower mean glomerular filtration rate (p < 0.001). Subjects with PLMSI > 15/h also had a higher prevalence of diabetes, hypertension, and beta-blocker or hypnotic treatments. The prevalence of antidepressant use was higher, but not statistically significant (p = 0.07). Single nucleotide polymorphisms (SNPs) within BTBD9 (rs3923809), TOX3 (rs3104788), and MEIS1 (rs2300478) genes were significantly associated with PLSMI > 15/h. Conversely, mean hemoglobin and ferritin levels were similar in both groups. In the multivariate analysis, age, male gender, antidepressant intake, RLS, and rs3923809, rs3104788, and rs2300478 SNPs were independently associated with PLMSI > 15/h. INTERPRETATION: PLMS are highly prevalent in our middle-aged European population. Age, male gender, RLS, antidepressant treatment, and specific BTBD9, TOX3, and MEIS1 SNP distribution are independent predictors of PLMSI > 15/h.

REM sleep behavior disorder and periodic leg movements during sleep in ALS.

OBJECTIVE: To assess sleep characteristics and the occurrence of abnormal muscle activity during sleep, such as REM sleep without atonia (RSWA), REM sleep behavior disorder (RBD), and periodic leg movements during sleep (PLMS), in patients with amyotrophic lateral sclerosis (ALS). METHODS: A total of 41 patients with ALS and 26 healthy subjects were submitted to clinical interview and overnight video-polysomnography. RESULTS: A total of 22 patients with ALS (53.6%) reported poor sleep quality. Polysomnographic studies showed that patients with ALS had reduced total sleep time, increased wakefulness after sleep onset, shortened REM and slow-wave sleep, and decreased sleep efficiency, compared to controls. Polysomnographic abnormalities were not different in patients reporting good or poor sleep and were not correlated to clinical and demographic variables. The PLMS index was significantly higher in patients with ALS than in healthy subjects, and 22 patients (53.6%) showed a PLMS index > 15/h, vs 4 (15.4%) controls (P < 0.001). Finally, two patients with ALS (4.9%) had RBD, and two more patients presented RSWA (4.9%), whereas no controls showed abnormalities of REM sleep. CONCLUSION: Patients with ALS frequently present abnormalities of sleep that can be documented both at the clinical interview and at the polysomnographic evaluation, including insomnia, fragmented sleep, and increased PLMS. Moreover, abnormalities of REM sleep can be found in some of these patients.

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.

While Isolated Periodic Limb Movement Disorder Significantly Impacts Sleep Depth and Efficiency, Co-Morbid Restless Leg Syndrome Mainly Exacerbates Perceived Sleep Quality.

BACKGROUND: Restless leg syndrome (RLS) and periodic limb movement (PLM) disorder (PLMD) can affect sleep quality and interfere with daytime functioning. Whether the co-morbidity of RLS further worsens daytime symptoms, sleep architecture and quality in patients with PLMs, is not yet fully clarified. METHODS: Sleep (polysomnography) and daytime symptoms of 47 drug-free patients, assigned to isolated PLMD or co-morbid RLS subgroups, were compared to controls in a retrospective cohort-study (n = 501). Associations between perceived sleep quality, fatigue, sleepiness, mood and sleep variables were explored descriptively. RESULTS: Although co-morbid patients showed worsened sleep quality, both patient groups showed similar sleepiness and affective symptoms. While significantly differing from controls, patients presented similarly increased light sleep, decreased slow-wave sleep and lowered sleep efficiency. Altered sleep quality, fatigue and sleepiness were significantly correlated to decreased slow-wave sleep and sleep fragmentation. Affective symptoms, fatigue and perceived sleep quality also correlated to PLM index. CONCLUSIONS: Sleep structure and efficiency were similarly impacted in isolated PLMD and in co-morbid RLS. RLS mainly worsened perceived sleep quality. Given that systematic treatment for isolated PLMD is currently not recommended, such results may question whether no or different-from-RLS treatment strategies are compatible with optimal care.

Sleep problems and internet addiction among children and adolescents: a longitudinal study.

Although the literature has documented associations between sleep problems and internet addiction, the temporal direction of these relationships has not been established. The purpose of this study is to evaluate the bidirectional relationships between sleep problems and internet addiction among children and adolescents longitudinally. A four-wave longitudinal study was conducted with 1253 children and adolescents in grades 3, 5 and 8 from March 2013 to January 2014. The sleep problems of the student participants were measured by parental reports on the Sleep Habit Questionnaire, which catalogues early insomnia, middle insomnia, disturbed circadian rhythm, periodic leg movements, sleep terrors, sleepwalking, sleep talking, nightmares, bruxism, snoring and sleep apnoea. The severity of internet addiction was measured by students' self-reports on the Chen Internet Addiction Scale. Based on the results of time-lag models, dyssomnias (odds ratio = 1.31), especially early and middle insomnias (odds ratio = 1.74 and 2.24), sequentially predicted internet addiction, and internet addiction sequentially predicted disturbed circadian rhythm (odds ratio = 2.40), regardless of adjustment for gender and age. This is the first study to demonstrate the temporal relationship of early and middle insomnia predicting internet addiction, which subsequently predicts disturbed circadian rhythm. These findings imply that treatment strategies for sleep problems and internet addiction should vary according to the order of their occurrence.

Restless Legs Syndrome and Depression: Effect Mediation by Disturbed Sleep and Periodic Limb Movements.

OBJECTIVE: To investigate an association between restless legs syndrome (RLS) and depression and to what extent sleep disturbance, periodic limb movements during sleep (PLMS), and antidepressant medication mediate this relationship. METHODS: A cross-sectional analysis was conducted of the Osteoporotic Fractures in Older Men Study data in 982 men assessed for RLS (International RLS Study Group scale [IRLSS]) and depression (Geriatric Depression Scale [GDS]), who underwent actigraphy (for sleep latency/efficiency) and polysomnography (for PLMS). Men were split into three groups: no RLS (N = 815), mild RLS (IRLSS ≤ 12, N = 85), moderate-to-severe RLS (IRLSS > 12, N = 82). Depression was defined as GDS score ≥ 6. Logistic and linear regression assessed associations of RLS and depression or number depressive symptoms, respectively. Models were adjusted for age, site, race, education, body mass index, personal habits, benzodiazepine/dopaminergic medication, physical activity, cardiovascular risk factors, and apnea-hypopnea index. RESULTS: Of 982 men, 167 (17.0%) had RLS. Depression was significantly associated with moderate-to-severe RLS after adjustment (versus no RLS: OR [95% CI] 2.85 [1.23, 6.64]). Further adjustment for potential mediators attenuated effect size modestly, most for sleep efficiency (OR: 2.85-2.55). Compared with no RLS, moderate-to-severe RLS was associated with the number of depressive symptoms after adjustment (adjusted means [95% CI]; no RLS: 1.14 [1.05, 1.24] versus IRLSS > 12: 1.69 [1.32, 2.11]). Further adjustment for potential mediators did not alter effect size. For men with PLMS index at least median, number of depressive symptoms significantly increased as RLS category became more severe. CONCLUSION: Depression is more common as RLS severity worsens. The RLS-depression relationship is modestly explained by sleep disturbance and PLMS.

Nocturnal periodic limb movements decrease antioxidant capacity in post-stroke women.

OBJECTIVES: Considerable evidence suggests that periodic limb movements during sleep (PLMS) are associated with cardiovascular risk and poor stroke outcome. However, the pathogenesis for this association in stroke patients remains largely unknown. MATERIALS AND METHODS: This cross-sectional study enrolled 112 consecutive patients who were admitted to rehabilitation ward due to ischemic stroke. Polysomnography and laboratory tests for oxidative stress and inflammatory biomarkers including C-reactive protein, interleukin 6, total antioxidant capacity (TAC), and urinary 8-hydroxy-2-deoxyguanosine were conducted. RESULTS: Patients were stratified into three categories according to their PLMS index. Patients in the PLMS index ≥15 group were significantly older (P = 0.011), presented a significantly higher National Institute of Health Stroke Scale at stroke onset (P = 0.032), and lower Barthel index (P = 0.035) than patients in the PLMS index <5 group. The level of TAC differed significantly (P = 0.018) among the three groups. Multivariate linear regression analyses show that the PLMS index was negatively and independently correlated with TAC (P = 0.024) in women. Besides, multivariate logistic regression analyses also reveal that patients with a PLMS index ≥15 compared with the referent PLMS index <5 had a 7.58-fold increased relative hazard for stroke recurrence (odds ratio 7.58, [1.31-43.88], P = 0.024). CONCLUSIONS: This study suggests that PLMS was independently associated with decreased antioxidant capacity in women with ischemic stroke.

Age and severity matched comparison of gender differences in the prevalence of periodic limb movements during sleep in patients with obstructive sleep apnea.

PURPOSE: The aim of this study was to investigate gender differences of periodic limb movements during sleep (PLMS) in patients with obstructive sleep apnea (OSA). METHODS: This was a case-control study recruiting 364 patients with OSA (182 men, 182 women) matched for age and apnea-hypopnea index (AHI). All participants underwent overnight polysomnography (PSG), followed by the multiple sleep latency test (MSLT) and the Epworth Sleepiness Scale (ESS). RESULTS: Women with OSA had a significantly higher prevalence of PLMS than men (24.2 vs. 15.9 %, p < 0.05). Women with OSA showed an increased prevalence of PLMS compared to men in the younger group aged ≤55 years (23.0 vs. 10.6 %, p < 0.05), but not in the older groups >55 years (25.3 vs. 21.6 %, p > 0.05). Binary linear regression analysis in OSA patients confirmed that women were more likely to have PLMS than men (OR 1.71, 95 % CI 1.00-2.92), particularly in patients with age ≤55 years old (OR 2.48, 95 % CI 1.06-5.79), after adjusting for age, BMI, AHI, and habits of smoking and drinking. CONCLUSIONS: The results demonstrate that, for patients with OSA, young women had significantly increased prevalence of PLMS compared to young men, but there was no difference in prevalence of PLMS between the men and women in the older age group.

Excessive fragmentary myoclonus in patients with Parkinson's disease: prevalence and clinico-polysomnographic profile.

OBJECTIVE AND BACKGROUND: Excessive fragmentary myoclonus (EFM) is characterized by subtle arrhythmic and excessive jerks that are usually asymmetric and asynchronous. EFM occurs in different areas of the body, mainly the face and distal parts of the arms and legs, and is detected by surface electromyography during sleep. The present study aimed to determine the prevalence of EFM in Parkinson's disease (PD) patients at a tertiary level outpatient clinic as well as to describe the clinical and polysomnographic profiles of these patients. METHODS: A total of 62 consecutive PD patients were included in the study. Patients were evaluated using the Brazilian version of the PD Sleep Scale, Portuguese Language version of Epworth's Daytime Sleepiness Scale validated for Brazilian population, Brazilian Portuguese version of PD Quality of Life Scale, and Global Deterioration Scale. Evaluation of the sleep disorders was performed by clinical interview and polysomnography. RESULTS: EFM was found in 62.7% of PD patients. EFM was found to be associated with obstructive sleep apnea syndrome and advanced age. CONCLUSIONS: EFM occurs in a significantly high proportion of PD patients and is related to obstructive sleep apnea syndrome (OSAS) and advanced age, so EFM should be systematically investigated by polysomnography (PSG) in PD patients.

Sleep disorders in Charcot-Marie-Tooth disease type 1.

INTRODUCTION: Obstructive sleep apnoea (OSA) and restless legs syndrome (RLS) have been reported in Charcot-Marie-Tooth disease (CMT) type 1A and axonal subtypes of CMT, respectively. The aim of this case-control study was to investigate both prevalence and severity of OSA, RLS and periodic limb movements in sleep (PLMS) in adult patients with genetically proven CMT1. PATIENTS AND METHODS: 61 patients with CMT1 and 61 insomnic control subjects were matched for age, sex, and Body Mass Index. Neurological disability in patients with CMT was assessed using the Functional Disability Scale (FDS). RLS diagnosis was based on a screening questionnaire and structured clinical interviews. All participants underwent overnight polysomnography. RESULTS: OSA was present in 37.7% of patients with CMT1 and 4.9% of controls (p<0.0001). The mean Apnoea Hypoponea Index (AHI) was significantly higher in patients with CMT1 than in control individuals (9.1/h vs 1.2/h). RLS was present in 40.9% of patients with CMT1 and in 16.4% of controls (p<0.001). In the CMT1 group, OSA was significantly more common in men and RLS in women. The AHI correlated with both age and the FDS score, the latter being a significant independent predictor of OSA. PLMS were found in 41.0% of patients with CMT1, but were not correlated with measures of sleep quality. CONCLUSIONS: In addition to known risk factors, CMT may predispose to OSA. RLS is highly prevalent not only in axonal subtypes of CMT but also in primarily demyelinating subforms of CMT. PLMS are common in CMT1, but do not significantly impair sleep quality.

Growing pains and periodic limb movements of sleep in children.

AIM: To investigate whether there was any association between growing pains (GP) and periodic limb movements of sleep (PLMS) in children referred for polysomnography (PSG), in light of the possible shared genetic determinants between GP and restless legs syndrome. METHODS: Records of all 903 children who underwent PSG at a paediatric hospital between January 2009 and May 2010 were retrospectively reviewed. Children aged 3-16 years, without neuromuscular or neurological/developmental disorders who were seen by a single sleep physician were included in the analysis. Data extracted included: current GP, PLMS index, mixed obstructive apnoea/hypopnoea index and patient demographics. GP was diagnosed in the pre-PSG consultation. RESULTS: GP was recorded in 43 of the eligible 230 children referred for PSG of whom 25.6% had a PLMS index ≥ 5/h, significantly higher than in the children without GP (10.2%) (odds ratio 3.04, χ(2) = 6.0, P = 0.014). The adjusted odds ratio for the association between GP and PLMS remained significant at 2.53 (95% CI 1.1-6.1, P < 0.05). A PLMS index ≥ 5/h was recorded in 30 of the 230 participants. GP and PLMS were also significantly multivariately associated with restlessness as the indication for PSG. CONCLUSIONS: Children with GP were three times more likely to have a PLMS index ≥ 5/h than children without GP on PSG. These results suggest that GP may be associated with PLMS, giving greater support for the hypothesis that GP might lie on the phenotypic spectrum of restless legs syndrome.

Association of Periodic Limb Movements and Obstructive Sleep Apnea With Risk of Cardiovascular Disease and Mortality.

BACKGROUND: Obstructive sleep apnea is a well-established risk factor for cardiovascular disease (CVD). Recent studies have also linked periodic limb movements during sleep to CVD. We aimed to determine whether periodic limb movements during sleep and obstructive sleep apnea are independent or synergistic factors for CVD events or death. METHODS AND RESULTS: We examined data from 1049 US veterans with an apnea-hypopnea index (AHI) <30 events/hour. The primary outcome was incident CVD or death. Cox proportional hazards regression assessed the relationships between the AHI, periodic limb movement index (PLMI), and the AHI×PLMI interaction with the primary outcome. We then examined whether AHI and PLMI were associated with primary outcome after adjustment for age, sex, race and ethnicity, obesity, baseline risk of mortality, and Charlson Comorbidity Index. During a median follow-up of 5.1 years, 237 of 1049 participants developed incident CVD or died. Unadjusted analyses showed an increased risk of the primary outcome with every 10-event/hour increase in PLMI (hazard ratio [HR], 1.08 [95% CI, 1.05-1.13]) and AHI (HR, 1.17 [95% CI, 1.01- 1.37]). Assessment associations of AHI and PLMI and their interaction with the primary outcome revealed no significant interaction between PLMI and AHI. In fully adjusted analyses, PLMI, but not AHI, was associated with an increased risk of primary outcome: HR of 1.05 (95% CI, 1.00-1.09) per every 10 events/hour. Results were similar after adjusting with Framingham risk score. CONCLUSIONS: Our study revealed periodic limb movements during sleep as a risk factor for incident CVD or death among those who had AHI <30 events/hour, without synergistic association between periodic limb movements during sleep and obstructive sleep apnea.