What is the clinical significance of periodic limb movements during sleep?

To understand better the clinical impact of periodic limb movements during sleep (PLMS) we analysed data from 51 patients who, following an adaptation night, presented a PLMS index > 5 during two consecutive nocturnal polysomnographic recordings. In the morning following each recording patients completed a questionnaire including five visual analogic scales (VAS): (1) I did not sleep well/I slept very well. (2) I feel very sleepy/I do not feel sleepy at all. (3) I feel very tired/I feel very dynamic. (4) Physically, I do not feel fit/physically, I feel fit. (5) Psychologically, I do not feel fit/psychologically, I feel fit. We compared the responses to these questions with the PLMS index, first inter-individually, then intra-individually between nights. RESULTS: The inter-individual analysis did not show correlations between the PLMS index and the questions (1) and (2). We found a significant correlation between the PLMS index and the questions (3) (r = -0.29; P < 0.05), (4) (r = -0.30; P < 0.05) and (5) (r = -0.39; P < 0.01). For the intra-individual analysis, we did not find correlations between the PLMS index and questions (1)-(3), but found a significant correlation with questions (4) (r = -0.28; P < 0.05) and (5) (r = -0.36; P < 0.01). CONCLUSION: PLMS per se, or the sleep changes induced by them, seem to be associated with decreased physical and psychological fitness on awakening.     

Clinical prediction of periodic leg movements during sleep in children

OBJECTIVE: To assess the utility of several symptoms and a questionnaire-based scale in the identification of children with periodic leg movements during sleep (PLMS). BACKGROUND: PLMS may have important consequences in some children, but the extent to which a diagnosis can be established by clinical history is unknown. METHODS: Subjects were patients aged 2-18 years who underwent polysomnography to assess for sleep-disordered breathing (SDB). Parents completed a Pediatric Sleep Questionnaire which contained items under consideration for inclusion in the desired scale. RESULTS: Subjects (n=113) had a mean age of 9.8+/-4.0 (SD) and 73 (65%) were male; 59 (52%) had SDB and 29 (26%) had five or more PLMS per hour of sleep (PLMI> or =5). Severity of SDB was not different among those with and without PLMI> or =5. Yes/no responses to several question-items--about restless legs, growing pains, leaving the bed at night, waking more than twice per night, waking feeling unrefreshed, and morning headaches--showed some association with PLMI> or =5 and were combined into a composite PLMS score artificially weighted toward the first two items. The PLMS score averaged 0.40+/-0.31 and ranged from 0.0 to 1.0; a 1 SD increase was associated with PLMI> or =5 (odds ratio=1.87, 95% confidence interval (1.15, 3.13), P=0.014) after adjustment for age, sex, and SDB severity. Sensitivity of a PLMS score>0.33 for PLMI> or =5 was 0.79, specificity was 0.56, positive predictive value was 0.38, and negative predictive value was 0.89. Internal consistency was reasonable (Cronbach's alpha=0.71), as was test-retest reliability (rho=0.62, P=0.0026, n=21 separate subjects). CONCLUSIONS: Restless legs, growing pains, sleep-maintenance insomnia, unrefreshing sleep, and morning headaches show moderate associations with polysomnographically-defined PLMS, but several other symptoms do not. These results require confirmation but suggest that clinical assessment and the PLMS score may be helpful but far from definitive.     

Sertraline and periodic limb movements during sleep: an 8-week open-label study in depressed patients with insomnia

BackgroundPrevious studies have reported that selective serotonin reuptake inhibitors (SSRIs) might induce or exacerbate periodic limb movements during sleep (PLMS). However, most of these studies were retrospective and cross-sectional studies with small sample sizes on a selective SSRI, fluoxetine. Because different SSRIs have different pharmacologic profiles, it was not certain if other SSRIs also might lead to PLMS.MethodsData were taken from an open-label 8-week trial of sertraline in depressive patients with insomnia (n = 31). Depressed patients were administered sertraline 50 mg at 8:00 am on the first day, and the dosage was subsequently titrated up to a maximum of 200 mg daily during the 8-week trial. All participants were tested by repeated polysomnography (PSG) (baseline, first day, 14th day, 28th day, and 56th day). Periodic leg movements (PLM) were visually counted and the PLM index (PLMI) was calculated. PLMS was defined as PLMI ⩾5, and significant PLMS was defined as PLMI ⩾15.ResultsCompared with baseline (PLMI, 3.6 ± 1.5), all PLMI indices increased on the immediate administration of sertraline on the first day (PLMI, 5.1 ± 3.9). From the 14th day onward, PLMI became stable and significantly higher than baseline and the first day (8.7 ± 3.1 on the 14th day, 8.3 ± 3.7 on the 28th day, and 8.5 ± 3.6 on the 56th day; F[11.81]; P = .003). The clinical responses and PSG characteristics continuously improved during the 8-week trial. The PLMS group (PLMI ⩾5) had a higher arousal index (AI) than the non-PLMS group on the 14th day (9.4 ± 5.5 vs 5.2 ± 3.7; t test, 4.22; P = .03) and the 56th day (8.1 ± 5.5 vs 4.3 ± 3.7; z score, 3.11; P = .04); albeit, there was no significant clinical disturbances in the PLMS group.ConclusionsPLMS were increased during sertraline treatment, but only a few of the PLMS reached the significant level. This effect of sertraline on PLMS might be dosage dependent. Although the sertraline-induced PLMS did not seem to cause significant clinical disturbance, the PLMS group (PLMI ⩾5) had a higher AI than the non-PLMS group. Thus clinicians should pay more attention to PLMS during SSRI antidepressant treatment.     

The validity of the PAM-RL device for evaluating periodic limb movements in sleep and an investigation on night-to-night variability of periodic limb movements during sleep in patients with restless legs syndrome or periodic limb movement disorder using this system

BackgroundThe status of night-to-night variability for periodic limb movements in sleep (PLMS) has not been clarified. With this in mind, we investigated the validity of PLMS measurement by actigraphy with the PAM-RL device in Japanese patients with suspected restless legs syndrome (RLS) or periodic limb movement disorder (PLMD) and the night-to-night variability of PLMS among the subjects.MethodsForty-one subjects (mean age, 52.1 ± 16.1 years) underwent polysomnography (PSG) and PAM-RL measurement simultaneously. Thereafter, subjects used the PAM-RL at home on four more consecutive nights.ResultsThe correlation between PLMS index on PSG (PLMSI-PSG) and PLM index on PAM-RL (PLMI-PAM) was 0.781 (P < .001). When the PLMSI cutoff value on PSG was set at 15 episodes per hour, the cutoff value for predicting this PLMSI level was 16.0 episodes per hour. When the condition was set to the level in which the mean interclass correlation coefficient reached ⩾0.9, the number of required nights for repeated measurements was 26 nights for subjects with PLMI of <15 episodes per hour and three nights for those with PLMI ⩾15 episodes per hour on PAM-RL.ConclusionsPAM-RL is thought to be valuable for assessing PLMS even in Japanese subjects. Recording of PAM-RL for three or more consecutive nights may be required to ensure the screening reliability of a patient with suspected pathologically frequent PLMS.     

Motor pattern of periodic limb movements during sleep

BACKGROUND: The pathophysiology of periodic limb movements in sleep (PLMS) in restless legs syndrome (RLS) is unclear. OBJECTIVE: The authors neurophysiologically investigated PLMS in patients with idiopathic RLS in order to obtain information on the origin and pathophysiology of the movements. METHODS: Ten patients with idiopathic RLS underwent electromyography with nerve conduction velocity (EMG-CV), somatosensory evoked potentials (SEPs), transcranial magnetic stimulation (TMS), nocturnal videopolysomnography, and multiple sleep latency test. The authors analyzed 100 consecutive PLMS for each patient to determine how frequently each muscle was involved in the PLMS; how frequently EMG activity started in a given muscle; and the time delay and pattern of activation between the first and the other activated muscles. RESULTS: EMG-CV, SEPs, and TMS findings were all normal; in PLMS, leg muscles were those more frequently involved, often with alternation of side. Axial muscles were rarely and upper limb muscles sometimes involved. The tibialis anterior was the most frequent starting muscle. There was no constant recruitment pattern from one PLMS episode to another, even in the same patient. There was no ordinate caudal or rostral spread of the EMG activity. CONCLUSION: The recruitment pattern indicates the engagement of different, independent, and sometimes unsynchronized generators for each PLMS. The authors hypothesize an abnormal hyperexcitability along the entire spinal cord, especially its lumbosacral and cervical segments, as the primary cause of PLMS, triggered by sleep-related factors located at a supraspinal but still unresolved level.     

Unilateral periodic limb movements during sleep in corticobasal degeneration.

Periodic limb movements in sleep (PLM) have been associated with several degenerative disorders and other focal or diffuse diseases. We present a patient with clinical diagnosis of corticobasal degeneration and sleep complaints, in whom video recording and polygraphic study confirmed the presence of right PLM. The unilaterality of the movements and the positron emission tomography findings (hypometabolism in the left frontoparietal, basal ganglia, and thalamic areas) suggest that the loss of inhibitory descending central pathways, with origin in the cortex or basal ganglia, may be involved in the pathogenesis of PLM.     

Lung to finger circulation time in sleep study and coronary artery calcification: the Multi-Ethnic Study of Atherosclerosis

BackgroundLung to finger circulation time (LFCT) measured from sleep studies may represent a novel physiologic marker for cardiovascular risk in patients with sleep disordered breathing (SDB). We hypothesized that sleep study-derived LFCT would improve risk classification of markers of subclinical cardiovascular disease.MethodsWe included participants in the Multi-Ethnic Study of Atherosclerosis (MESA) Sleep cohort with moderate-severe SDB (apnea hypopnea index [AHI] ≥ 15/hr) (N = 598).ResultsThose with average LFCT above the median (19.4 s) (vs. shorter LFCT) tended to be older, more obese and male. In multivariable analysis, no significant associations were found between average LFCT and subclinical cardiovascular markers including coronary artery calcium, carotid intima-media thickness or left ventricular hypertrophy. However, there was modest improvement in risk classification of coronary artery calcification as compared with AHI alone when average LFCT was added to AHI (C statistics 0.53 vs. 0.62, p = 0.0066).ConclusionsIn conclusion, LFCT may be a useful addition to conventional SDB metrics to improve cardiovascular risk assessment.     

Clinical significance of pulse rate rise during sleep as a screening marker for the assessment of sleep fragmentation in sleep-disordered breathing

OBJECTIVE: To assess the clinical utility of the frequencies of transient increases of pulse rate, non-invasively measured with a pulseoximeter, as an indirect indication of the degree of cortical arousal, measured conventionally on an electroencephalogram (EEG), in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients. PATIENTS AND METHODS: Thirty-three consecutive patients referred with suspected OSAHS were studied. Polysomnography (PSG) with determination of esophageal pressure (Pes) and pulseoximetry was monitored to identify breathing-related EEG arousal (B-Ar) associated with apnea, hypopnea or respiratory effort and the frequencies of pulse rate increases. We also assessed the association of B-ArI (defined as the number of B-Ar per hour) with the pulse rate rise index (PRRI)-X(X=4-10) (defined as the number of pulse rate increases per hour). In addition, the sensitivity and specificity of PRRI for the assessment of a B-ArI cutoff point of 30 were calculated. RESULTS: The sensitivity and specificity of pulseoximetry for different thresholds of PRRI-X(X=4-10) demonstrated that the greatest diagnostic accuracy for detecting frequent arousal (B-ArI > or =30) occurs at a cutoff point of 40 PRRI-6 with a sensitivity of 0.88 and specificity of 0.86. This point shows a significant area under the curve of 0.84. In addition, a statistically significant correlation between PRRI-6 and B-ArI (r=0.68, P<0.0001) was observed. CONCLUSIONS: The transient increases in pulse rate measured by pulseoximetry during sleep may be a useful clinical marker for predicting the degree of arousal in OSAHS patients, and may, in addition, prevent cases with frequent respiratory effort related arousals from being overlooked. However, further studies are required to improve the confidence level of the PRRI and to investigate the causes of overestimation of EEG arousals.     

Periodic limb movements in sleep: Prevalence and associated sleepiness in the Wisconsin Sleep Cohort

Objectives

Periodic limb movements in sleep (PLMS) are thought to be prevalent in elderly populations, but their impact on quality of life remains unclear. We examined the prevalence of PLMS, impact of age on prevalence, and association between PLMS and sleepiness.

An alternative measure of sleep fragmentation in clinical practice: the sleep fragmentation index

BACKGROUND AND PURPOSE: Micro-arousals (MA) are commonly considered as sleep components reflecting sleep fragmentation. However, their elucidation is time-consuming, with considerable inter-observer variability. The aim of our study was to investigate the usefulness of a sleep fragmentation index (SFI) to detect sleep disruption in a large sample of patients. PATIENTS AND METHODS: Five-hundred ninety-eight polysomnographic studies made in controls and patients were examined. The SFI was calculated as the total number of awakenings and sleep stage shifts divided by total sleep time. RESULTS: In the whole group a significant correlation was found between the SFI and the MA index (MAI) (P<0.001) with good agreement across a wide range of values. When patients were stratified according to final diagnosis a significant relation was noted for patients with insomnia (P<0.001), parasomnia (P<0.001), circadian schedule disorders (P<0.001) and sleep related breathing disorders (P< 0.001). Lower values were found in controls (P<0.01) and in patients with periodic limb movement disorder and/or restless legs syndrome (P<0.05). In 111 patients having two consecutive recording nights, a good reproducibility was present with no differences between nights (P=ns) and with significant correlation (P<0.001). CONCLUSIONS: The SFI seems to be an accurate, reproducible and easy method to detect sleep fragmentation in patients with sleep disorders. Further studies are needed to validate the usefulness of this tool in clinical practice.     

Influence of respiratory allergy and restless sleep on definite sleep bruxism: a cross-sectional clinical study

ObjectiveThis cross-sectional clinical study evaluated the associations between sociodemographic, occupational, clinical conditions, psychological and sleep quality variables on definite sleep bruxism (SB).MethodsAll records obtained from adults (aged 20–60 years) and the elderly (aged >60 years) who had undergone polysomnography (PSG) at a private medical outpatients’ clinic from July 2017 to February 2018 were reviewed. Data from a questionnaire, based on the criteria of the American Academy of Sleep Medicine (AASM), were also gathered. Definite SB data pattern distribution was analyzed, and multivariate Poisson regression with robust variance was used to assess the associations between definite SB diagnosis, determined via PSG recordings, and the independent variables. A significance level of 5% was adopted.ResultsA total of 240 individuals were included in the study and the SB prevalence was 7.08% (n = 17). The adjusted Poisson regression analysis revealed association between definitive SB and individuals with respiratory allergy (PR = 3.63; 95% CI:1.01–13; P = 0.047) and restless sleep (PR = 2.97; 95% CI:1.04–8.50; P = 0.042).ConclusionThis study found associations between definite SB and clinical conditions (respiratory allergy) and sleep behavior (restless sleep). Knowledge regarding factors associated with definite SB can contribute to decision making in the clinical setting and management strategies involving a multidisciplinary approach.     

Longitudinal relationships of periodic limb movements during sleep and incident atrial fibrillation

ObjectivesThis study aimed to examine relationship between periodic limb movements during sleep (PLMS) and incident atrial fibrillation/flutter (AF).MethodsProspective multicenter cohort (n = 2273: adjudicated AF group; n = 843: self-reported AF group) of community-dwelling men without prevalent AF were followed for an average of 8.3 years (adjudicated) and 6.5 years (self-reported). PLMS index (PLMI, <5 (ref), ≥5 to <30, ≥30) and PLM arousal index (PLMAI, <1 (ref), ≥1 to <5, ≥5) were measured by polysomnography. Incident adjudicated and self-reported AF were analyzed by Cox proportional hazards and logistic regression, respectively, and adjusted for age, clinic, race, body mass index (BMI), alcohol use, cholesterol level, cardiac medications, pacemaker, apnea–hypopnea index, renal function, and cardiac risk. The interaction of age and PLMS was examined.ResultsIn this primarily Caucasian (89.8%) cohort of older men (mean age 76.1 ± 5.5 years) with BMI of 27.2 ± 3.7, there were 261 cases (11.5%) of adjudicated and 85 cases (10.1%) of self-reported incident AF. In the overall cohort, PLMI and PLMAI were not associated with adjudicated or self-reported AF. There was some evidence of an interaction of age and PLMI (p = 0.08, adjudicated AF) and PLMAI (p ≤ 0.06, both outcomes). Among men aged ≥76 years, the highest PLMI tertile was at increased risk of adjudicated AF (≥30 vs. <5; hazard ratio (HR) = 1.63, 1.01–2.63) and the middle PLMAI tertile predicted increased risk of both outcomes (1 to <5 vs. <1; adjudicated, HR = 1.65, 1.05–2.58; self-reported HR = 5.76, 1.76–18.84). No such associations were found in men aged <76 years.ConclusionsAlthough PLMS do not predict AF incidence in the overall cohort, the findings suggest PLMS increases incident AF risk in the older subgroup.     

抑郁症住院患者适应性睡眠改变的研究

目的　了解抑郁症住院患者适应性睡眠改变的情况。方法　连续两晚测量 14例抑郁症住院患者的多导睡眠图 ,比较其两晚的睡眠参数。结果　患者的睡眠总时间、睡眠潜伏期、醒起时间、运动觉醒时间、醒觉次数、睡眠效率、睡眠结构、快动眼 (REM)睡眠潜伏期、REM强度、REM密度、REM时间、REM周期数等指标 ,第 1晚与第 2晚的差异均无显著性 (P均 >0 0 5 )。结论　抑郁症住院患者存在适应性睡眠改变的相对缺乏 ,其第 1晚的睡眠资料不应轻易地丢弃。     

Association between periodic limb movements during sleep and cerebral small vessel disease

ObjectivePeriodic limb movements (PLMs) can increase the risk of cardiovascular disease and mortality. Small vessel disease (SVD) has been considered a precursor to symptomatic stroke. We aimed to investigate the association between PLMs and cerebral SVD.MethodsWe enrolled participants who visited our clinic for the evaluation of sleep disturbance and underwent overnight polysomnography and brain magnetic resonance imaging. The processing steps included rating and analyzing white matter hyperintensities (WMHs), cerebral microbleeds (CMBs), asymptomatic lacunar infarctions (ALIs), perivascular spaces (PVSs), and calculating the total SVD score. Logistic regression and correlation analyses were used to examine the association between PLMs during sleep (PLMS) and SVD.ResultsA total of 31 (19 men and 12 women) patients with PLMS index ≥ 15/h were enrolled. The mean age was 61.7 years and the median PLMS index was 46.5/h. A total of 29 controls (16 men and 13 women) with PLMS index < 5/h were also included. PLMS index was positively associated with an increase in WMHs, ALIs, and PVSs (odds ratio [OR] = 1.022, 95% confidence interval [CI] = 1.003–1.040, p = 0.008; OR = 1.024, 95% CI = 1.006–1.043, p = 0.010; OR = 1.029, 95% CI = 1.010–1.049, p = 0.003, respectively). Correlation analyses revealed that total SVD score was significantly correlated with PLMS index (r = 0.504, p < 0.001).ConclusionsAn elevated PLMS index was associated with an increase in WMHs, ALIs, PVSs, and total SVD burden. Our study suggests that PLMS is a marker for SVD, which carries a potential risk for progression to overt stroke or cognitive impairment.