Periodic Leg Movements In Sleep Index Research Articles

Periodic leg movements in sleep before and after continuous positive airway pressure treatment in patients with obstructive sleep apnea

Introduction Periodic leg movements in sleep (PLMS) are commonly reported to coexist together with obstructive sleep apnea syndrome (OSAS). Although PLMS usually disappear following continuous positive airway pressure (CPAP) treatment, an increasing number of patients have now introduced to have treatment-emergent PLMS. The underlying etiopathogenesis of temporal relationship between PLMS and CPAP treatment waits to be explored. Materials and methods Here we evaluated clinical and polysomnographic (PSG) data in four groups of OSAS patients: 10 patients with PLMS at first night and also at CPAP treatment night (present- present, PP group), 10 patients with PLMS at first night but not at CPAP treatment night (present-absent, PA group), 10 patients without PLMS at first night or at CPAP treatment night (absent-absent, AA group), and 10 patients without PLMS at first night but at CPAP treatment night (absent- present, AP group). Results Gender, age and presence of restless legs syndrome were similar between groups. Among PSG parameters, only the percentage of N3 sleep was significantly longer in patients without PLMS at first night (AA and AP group, p = 0.004).The comparison of variables between two nights in each group revealed that, other than significantly decreased RDI in every group, PLMS index was also significantly decreased in PA group (p = 0.005) and increased in AP group (p = 0.041).Decrease in PLMS index was positively correlated with decrease in RDI in PA group (p = 0.053), and increase in PLMS index positively correlated with increase in percentage of N3 sleep stage in AP group (p = 0.038). We performed cyclic alternating pattern (CAP) analysis. At first night analysis, time, rate, cycle and index of CAP were lowest in AA group, and highest in PA group (p 0.05). There was no significant difference in CAP parameters in different sleep stages as N1, N2 and N3. In PP group, CAP time of A1 subtype in N2 sleep stage; and CAP time, CAP cycle and CAP index of A2 subtype in N2 sleep stage were observed to persist without any decrease at second CPAP night. In AP group, CAP time, CAP rate, CAP cycle and CAP index of A1 and A2 subtypes were observed to persist, or even increase, in N1 and N2 sleep stages at CPAP night; while total CAP time of A3 subtype was decreased. In PA group, as well as in AA group, CAP parameters decreased prominently at CPAP night in compared to first night. Conclusion Different mechanisms are probably responsible from vanishing, non- vanishing or newly-emerging PLMS in OSAS patients following CPAP treatment. Macrostructural elements of sleep do not seem to explain them all. Microstructural CAP analysis of the sleep showed different patterns of cortical-subcortical activation in different stages of sleep. Activation of different sites within the same arousal system, triggered by internal (such as rebound NREM sleep) or external (CPAP) stimuli, may explain these differences.

REM sleep behavior disorder and periodic leg movements in sleep in patients with amyotrophic lateral sclerosis

In the last few years, it has been increasingly recognized that patients with amyotrophic lateral sclerosis (ALS) frequently suffer of sleep-related complaints, including insomnia, restless legs syndrome, and daytime sleepiness, although, in the past, many of the nocturnal symptoms have been mainly ascribed to chronic respiratory insufficiency and hypoventilation. In addition, excluding few single cases reported, polysomnographic studies did not look for abnormal motor activity during sleep that could be indicative of Rapid Eye Movements (REM) sleep behavior disorder (RBD) and REM sleep without atonia (RSWA), which are highly prevalent in other neurodegenerative disorders with brainstem involvement. Finally, data on the presence of periodic leg movements in sleep (PLMS) in patients with ALS are sparse. We sought to assess sleep characteristics and the occurrence of abnormal muscle activity during sleep, such as RSWA, RBD, and PLMS in patients with ALS. Forty-one patients with ALS and 26 healthy subjects were submitted to clinical interview and overnight video-polysomnography. Twenty-two patients with ALS (53.6%) reported poor sleep quality. Polysomnographic studies showed that patients with ALS had reduced total time of sleep, increased wakefulness after sleep onset, shortened REM and slow wave sleep, and decreased sleep efficiency compared to control subjects. Polysomnographic abnormalities were not different in patients reporting good or poor sleep, and were not correlated to clinical and demographic variables. PLMS index was significantly higher in patients with ALS than in healthy subjects, and 22 patients (53.6%) showed a PLMS index > 15, vs 4 (15.4%) control subjects ( p < 0.001). Finally, two patients with ALS (4.9%) had RBD, and two more patients presented RSWA (4.9%), whereas no control subjects showed abnormalities of REM sleep. 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 sometimes be found in these patients. The authors would like to thank Dr. A. Mattaliano, Ospedale Civico ARNAS of Palermo, Dr. V. La Bella, University of Palermo-Italy, and Dr. G. Borghero, University of Cagliari-Italy, for their important contribution.

Influence of periodic leg movements in sleep on stroke outcome

Destructive lesions, as cerebrovascular diseases, have been shown to lead to the development of periodic leg movements in sleep (PLMS), secondary to the loss of cortical or subcortical inhibition exerting on the brainstem generators. We designed a prospective study to investigate the association of PLMS with a clinical outcome in 24 patients with acute ischemic cerebrovascular diseases. The medical history of patients and risk factors of ischemic stroke were questioned. A whole-night polysomnographic (PSG) recording was performed; detailed PSG data including PLM index and PLM-arousal index were analyzed. Stroke outcome was assessed at 3 weeks and 3 months by the National Institute of Health Stroke Scale (NIHSS) and Barthel Scale (BS). The results of NIHSS and BS were correlated with demographic parameters and PSG parameters including PLMS data. However, none of them showed a significant correlation with clinical parameters. The delta change in outcome measures was correlated with the PLMS index, which was also not significantly different at the subacute or chronic phase. On the other hand, the correlation between delta changes in mean NIHSS and BS with mean arousal-associated PLMS index showed a borderline significance at the subacute stage, and significant correlation was observed at the chronic phase. Increased sympathetic activation secondary to RLS or arousal reactions following PLMS have been suggested as the underlying pathophysiology of cardiovascular complications. PLMS, particularly with accompanying autonomic arousal, may therefore be a risk factor for stroke, and display a negative influence on stroke outcome.

Relationship of periodic leg movements and severity of restless legs syndrome: A study in unmedicated and medicated patients

Objective To evaluate the relationship of the severity of restless legs syndrome (RLS) as assessed by a subjective, patient-rated scale (International RLS Study Group Rating Scale, IRLS), and of periodic leg movements in sleep (PLMS) as an objective parameter, in two different patient populations. Methods Data of 200 unmedicated patients with idiopathic RLS were evaluated. Group 1 ( n = 100) consisted of selected patients participating in the Pergolide European Australian RLS (PEARLS) study. Group 2 ( n = 100) represented an outpatient RLS population investigated in a Sleep Disorders Center. Additionally, Group 1 was also evaluated after a 6 week double-blind treatment period, where 47 patients received pergolide and 53 patients placebo. Results In unmedicated patients, IRLS scores correlated with the PLMS-arousal index ( r = 0.22, p = 0.033) but not with the PLMS index in Group 1 while no correlation was found in Group 2. The change of the IRLS score under treatment in Group 1 correlated significantly both with the change of the PLMS index ( r = 0.42, p < 0.001) and the change of the PLMS-arousal index ( r = 0.38, p < 0.001). Conclusions The IRLS adequately reflects treatment changes of PLMS indices. In unmedicated patients, the IRLS correlates with PLMS indices probably only in selected RLS populations with predefined PSG criteria and high PLM activity. Significance The IRLS is an appropriate subjective rating scale for measuring treatment effects in RLS.

Restless legs syndrome and motor activity during sleep in spinocerebellar ataxia type 6

Background and purpose We investigated the frequency of restless legs syndrome (RLS) and sleep disturbance in spinocerebellar ataxia type 6 (SCA6). Patients and methods Five patients out of three multigenerational SCA6 families underwent a standardized investigation protocol including clinical interview for RLS, neurophysiological evaluation as well as the clinical assessment of ataxia. Polysomnography (PSG) was performed during two consecutive nights. Results Two out of five patients fulfilled the clinical criteria for RLS. A periodic leg movements in sleep (PLMS) index>15/h was present in four of the five patients; a PLMS index>5/h was present in all patients. Significant disturbance of rapid eye movement (REM) sleep was not found. None of the patients had REM sleep behaviour disorder. Only one patient had mild REM sleep without atonia. Conclusions Our pilot study suggests only minor sleep abnormalities in SCA6.

Variability of Periodic Leg Movements in Various Sleep Disorders: Implications for Clinical and Pathophysiologic Studies

Periodic leg movements in sleep (PLMS) are a frequent phenomenon in various sleep disorders. The pathophysiology of PLMS is still not understood, but recent studies indicate a hypoactivity of the dopaminergic system in subjects with PLMS. In the present study, we investigated the intrasubject variance of PLMS from one night to the other because a fluctuation in the number of PLMS may influence the outcome of pharmacologic and pathophysiologic studies. Retrospective observational study. Data collection occurred in the sleep disorders unit. Sleep electroencephalogram and PLMS data of 115 patients with PLMS monitoring over 2 consecutive nights were evaluated retrospectively. Patients were grouped into the following diagnostic categories: restless legs syndrome, insomnia secondary to a psychiatric disorder, primary insomnia, sleep apnea syndrome, and narcolepsy or idiopathic hypersomnia. N/A. In 27% of the entire patient population, we found a considerable variability of the PLMS index (difference between nights > 10/hour) and, in 19% of patients, variability of the PLMS arousal index (difference between nights > 5/hour) across the 2 investigated nights. The intraindividual variance occurred most frequently and to the highest extent in patients with RLS. The variability of PLMS indexes should considered if the PLMS recording is performed in support of the clinical diagnosis or in the interpretation of studies investigating drug efficacy. Furthermore, the variability of PLMS may be an indicator of an instability of the dopaminergic system that should be taken into account in studies investigating central nervous system dopaminergic activity.

Do periodic leg movements influence patients' perception of sleep quality?

Background and purpose: Periodic leg movements in sleep (PLMS) are a common finding in various sleep disorders. Whether PLMS are an epiphenomenon or are causally related to the presence of sleep–wake disturbances is still being debated. We investigated the relationship of the occurrence of PLMS to patients' perception of sleep quality during a night of polysomnography in various sleep disorders. Methods: The retrospective evaluation included PLMS recordings over two nights of 78 consecutive patients diagnosed with a restless legs syndrome, primary insomnia or insomnia associated with a psychiatric disorder. The subjects' perception of sleep during the polysomnography night was assessed by the subscale ‘sleep quality’ of the validated self-rating sleep questionnaire SFA (SFA-SQ). Results: SFA-SQ scores correlated with the PLMS index (number of PLMS per hour of sleep) only in patients with restless legs syndrome during the first of the two nights investigated ( r=−0.464, P<0.01). PLMS appear to have a low impact on the subjects' perception of sleep quality. The correlation of subjective sleep quality to PLMS index in the first of the two investigated nights in RLS patients may reflect an adaptation effect. Conclusion: The results of our study favor the hypothesis that PLMS most likely are not the primary cause of sleep disturbances in these patient groups.

Immobilization tests and periodic leg movements in sleep for the diagnosis of restless leg syndrome.

Patients with restless leg syndrome (RLS) complain of motor restlessness, usually occurring while they rest in the evening. Two immobilization tests have been described to assess leg restlessness in these patients. In the first test, the patient sits in bed with his or her legs outstretched while electromyograms are recorded from right and left anterior tibialis muscles for an hour (Suggested Immobilization Test [SIT]); in the second test, the legs are immobilized in a stretcher (Forced Immobilization Test [FIT]). In the current study, the SIT and the FIT were compared in patients with RLS and normal control subjects matched for age and sex. More leg movements were seen in patients than in controls during immobilization tests, especially the SIT. These movements were periodic, occurring at a frequency of approximately one every 12 seconds. The SIT (index > 40) was found to discriminate between RLS and control subjects better than the FIT (index > 25). Patients were also recorded during two consecutive nights to measure periodic leg movements in sleep (PLMS). A SIT index greater than 40 and a PLMS index greater than 11 (highest PLMS index of 2 consecutive nights) were found to discriminate patients with RLS from control subjects with similar power. With each of these two measures, the clinical diagnosis was correctly predicted in 81% of patients and 81% of the control subjects. The SIT has several advantages over the measure of the PLMS index; it does not require an all-night polygraphic recording and can be administered several times a day to measure circadian fluctuation of motor restlessness.

Nonpharmacologic treatment of periodic leg movements in sleep.

The effects of a 30-minute stimulation of the dorsiflexors of the feet and toes before bedtime were investigated in eight patients with periodic leg movements in sleep (PLMS). None were taking medications at the time of the investigation. All subjects were treated with the EMS-250 Neuromuscular Stimulator, which has a maximum output per channel of 1.5mA and a frequency of 47Hz. Stimuli were delivered via a pulse train (on for 1.5sec and off for 1.8sec). A single all-night polysomnogram after this stimulation showed that all patients responded to stimulation, with reduction of leg movements from an average pretreatment PLMS index of 44.6 per hour to a posttreatment PLMS index of 14 per hour (p less than .01). Nocturnal leg movements were primarily reduced during the non-REM sleep. Multiple indices of sleep continuity did not change significantly, although there was a trend toward better sleep consolidation.