• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.26-31
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• 2003

Restless leg syndrome (RLS) and periodic limb movement of sleep (PLMS), often concurrent, come under diagnosed disorders of sleep and treatable condition. RLS symptoms are evoked in the limbs at rest and increase in the evening and during the night. PLMS is characterized by periodic episodes of repetitive limb movements caused by muscle contractions during sleep. RLS is often associated with a sleep complaint and PLMS. Both RLS and PLMS represent one of the most commonly encountered sleep disorders in a primary care setting. The circadian rhythm and the presence of PLMS cause sleep disturbances in RLS. The emphasis on pathophysiology includes consideration of central nervous system localization, neurotransmitter, and the role of iron metabolism. Dopaminergic agents are considered the treatment of choice for RLS and PLMS. With proper diagnosis and effective treatment patients' ability to fall asleep and maintain sleep improves, and their sense of well being increases.

• Sleep Medicine and Psychophysiology
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• v.30 no.1
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• pp.3-8
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• 2023

Periodic limb movement disorder (PLMD) is a sleep-related movement disorder characterized by involuntary, rhythmic limb movements during sleep. While PLMD itself is not considered life-threatening, its association with certain underlying health conditions raises concerns about mortality risks. PLMD has been found to be associated with cardiovascular diseases such as hypertension and cardiovascular disease. The fragmented sleep caused by the repetitive limb movements and associated arousals may contribute to sympathetic activation, chronic sleep disruption, sleep deprivation, and subsequent cardiovascular problems, which can increase mortality risks. The comorbidities and health factors commonly associated with PLMD, such as obesity, diabetes, and chronic kidney disease, may also contribute to increased mortality risks. PLMD is often observed alongside other neurological disorders, including restless legs syndrome (RLS) and Parkinson's disease. The presence of PLMD in these conditions may exacerbate the underlying health issues and potentially contribute to higher mortality rates. Further research is needed to elucidate the specific mechanisms linking PLMD to mortality risks and to develop targeted interventions that address these risks.

• Sleep Medicine and Psychophysiology
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• v.4 no.2
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• pp.191-200
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• 1997

Objectives : Periodic limb movements during sleep (PLMS) may cause arousals that may lead to non-restorative sleep. PLMS is characterized by long sleep latency, sleep fragmentation, frequent stage shifts, and rarity of stages 3/4 NREM sleep on polysomnography. However, controversies have existed and it still remains to be elaborated whether PLMS actually causes insomnia, since normal persons happen to have PLMS. Clinically, it would be crucial to know factors which might disturb sleep in PLMS. We became interested in Coleman's theory(1980) that invariant periodic movements disturb patients' sleep less. Though, Coleman's study seems to have been confounded by including PLMS patients with various co-morbid sleep disorders. Therefore, we attempted to study in patients only with PLMS the effects of movement patterns on sleep architecture. Methods : In 27 patients diagnosed as having PLMS only with clinical interview and nocturnal polysomnography, we studied the relationship between the movement patterns such as mean duration and variability of periodic limb movement's interval and the sleep architecture variables. Results : The shorter and the more regular the limb movement intervals were, the fewer arousals followed. The movement intervals of the older patients were shorter and more regular than the younger patients. The probability of the accompanying arousal with each limb movement increased as the duration and variance of the movement intervals increased. It decreased as the age and the frequency of limb movements increased. Among these factors the most significant one was the mean duration of the movement intervals. In other words, the shorter the movement intervals were, the less disturbed sleep was. Conclusion : PLMS frequency increases with aging but the probability of the accompanying arousal with each movement decreases with aging. Sleep-disturbing effects of PLMS depends more on the duration and variability of movement intervals than the PLMS frequency.

• Journal of Sleep Medicine
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• v.15 no.2
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• pp.62-67
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• 2018

Objectives: Restless leg syndrome (RLS) is a common sensorimotor disorder and is frequently associated with periodic limb movement in sleep (PLMS). Also about one third of patient with RLS have periodic limb movement during wakefulness (PLMW). However there is little research on the correlation between PLMW and RLS. We aimed to evaluate difference in sleep characteristics between patients with RLS with PLMW and those without PLMW. Methods: Our study included twenty eight RLS patients. Subjects underwent suggested immobilization test (SIT) prior to one full-night polysomnography study. Patients were classified into two groups according to the presence of PLMW based on SIT-PLMW index. Polysomnographic findings, subjective sleep quality, and hematologic results were analyzed and compared between the two groups. Results: Mean age of patient with frequent PLMW (SIT-PLMW ${\geq}40/hr$) was significantly higher. RLS patients with frequent PLMW were also significantly related to insomnia severity. The PLMS index was higher in patients with PLMW and showed a significant correlation with the PLMW index. Conclusions: PLMW influence sleep quality such as insomnia and is correlated with movement during sleep.

• Sleep Medicine and Psychophysiology
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• v.30 no.1
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• pp.9-12
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• 2023

Periodic limb movements during sleep (PLMS) are prevalent in various sleep disorders, such as restless legs syndrome (RLS), periodic limb movements disorder, obstructive sleep apnea (OSA), REM sleep behavior disorder (RBD), and narcolepsy. PLMS has been hypothesized to be related to the decline of dopaminergic transmission. In RLS, PLMS is suggested to be related to iron deficiency and symptom severity. PLMD is a rare sleep disorder, and the role of PLMS in PLMD has not been clearly investigated yet. PLMS in OSA, which remain after proper PAP therapy, may need further management. The clinical relevance of PLMS in RBD and narcolepsy have not been investigated thoroughly and need further studies. Whether PLMS are to be considered as a mere symptom of individual sleep disorders or not can be elucidated through studies investigating the efficacy of therapeutic approaches to reduce PLMS in various sleep disorders.

• Sleep Medicine and Psychophysiology
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• v.7 no.2
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• pp.84-87
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• 2000

The periodic limb movement (PLM) disorder is a disease of motor sign mainly in the lower extremities, whereas the restless leg syndrome (RLS) accompanies sensory symptoms in the lower extremities. These two disorders may occur in the one patient, which implies possible common pathophysiological background in those disorders. The aim of this article is to review the clinical features, diagnostic criteria, electrophysiological characteristics of the two disorders and their relation to neurological disorders.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.34-42
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• 2000

Objectives: Periodic limb movements in sleep(PLMS) is a moderately prevalent disorder, of which pathophysiology remains largely unknown. PLMS has been reported to be common in patients with obstructive sleep apnea syndrome(OSAS), but reports on their relationship have been inconsistent in previous studies. Inconsistency of results may be attributable to insufficient number of the study subjects. We attempted to explore the influence of OSAS on PLMS in a large number of subjects. Methods: Three hundred and twenty subjects(M : F=192:128) with PLMS, as identified by the nocturnal polysomnography, were studied. Sample mean age was 53.1(SD=15.1) years and their mean periodic limb movement index(PLMI) is 25.2/hr (SD=24.8). PLMS subjects were divided into two groups, based on the presence or absence of OSAS. Periodic limb movement indices and sleep parameters between two groups were analyzed to evaluate the effects of OSAS on PLMS. Results: Each of PLMI and PLMI with arousal(PLMAI) correlated positively with age. PLMI of men was larger than that of women (p<0.01). The presence of comorbid OSAS independently had influence on PLMI(t=-2.20, p<0.05), but not PLMAI. There were no significant differences between the two groups in their PLMI, PLMAI and sleep parameters. However, the two groups differed in PLMI-correlated sleep parameters. In PLMS subjects with comorbid OSAS, PLMI was negatively correlated with each of slow wave sleep time and REM sleep time. In subjects without comorbid OSAS, PLMI was negatively correlated with sleep efficiency. Conclusion: PLMS patients with OSAS turned out to have increased PLMI than those without OSAS We suggest that OSAS patients may have subtle autonomic arousals and these arousals could, in part, express themselves as PLM.

• Childhood Kidney Diseases
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• v.20 no.2
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• pp.50-56
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• 2016

Purpose: Nocturnal enuresis (NE) is one of the most common problems in childhood. NE has a multifactorial etiology and is influenced by sleep and arousal mechanisms. The aim of the present study was to prospectively evaluate sleep problems and patterns in children with NE compared with normal healthy controls. Methods: Twenty-eight children with NE and 16 healthy controls were included in the study. To evaluate sleep habits and disturbances, parents and children filled out a questionnaire that included items about sleep patterns and sleep-related behaviors prior to treatment for NE. Demographic factors and other data were compared for the two groups based on the responses to the sleep questionnaire. Results: Night awakening, sleepwalking, and periodic limb movements were more prevalent in children with NE, but symptoms of sleep-disordered breathing were not increased in this group. There were statistically significant differences in periodic limb movements and daytime sleepiness between the two groups. Conclusion: Children with NE seemed to have more sleep problems such as night awakening, sleepwalking, and periodic limb movements. In addition, a higher level of daytime sleepiness and hyperactivity in patients with NE suggested a relationship between NE and sleep disorders.

• Annals of Clinical Neurophysiology
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• v.14 no.1
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• pp.7-11
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• 2012

Polysomnography is used to diagnose many types of sleep disorders including sleep apnea, periodic limb movement disorder, REM sleep behavior disorder, parasomnias, and narcolepsy. It is a comprehensive recording of the biophysiological changes that occur during sleep. The polysomnography monitors many body functions parameters including EEG, EOG, EMG, ECG, respiratory airflow, respiratory effort, and pulse oximetry during sleep. Multiple Sleep Latency Test (MSLT) is performed for diagnosing narcolepsy and excessive daytime sleepiness. It is usually to be done after an overnight polysomnography. The test consists of four or five 20-minute nap opportunities that are scheduled two hours apart.

• Sleep Medicine and Psychophysiology
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• v.25 no.2
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• pp.51-57
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• 2018

Objectives: Previous studies have shown that periodic limb movements in sleep (PLMS) could be one of risk factors for cardiovascular morbidity. The purpose of this study was to investigate the association between PLMS and blood pressure changes during sleep. Methods: We analyzed data from 358 adults (176 men and 182 women) aged 18 years and older who were free from sleep apnea syndrome (Respiratory Disturbance Index < 5) and sleep disorders such as REM sleep behavior disorder or narcolepsy. Demographic characteristics, polysomnography records, and clinical variable data including blood pressure, body mass index, alcohol, smoking, and current medications were collected. In addition, self-report questionnaires including the Beck Depression Index, Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index were completed. Blood pressure change from bedtime to awakening was compared between the two periodic limb movement index (PLMI) groups [low PLMI ($PLMI{\leq}15$) and high PLMI (PLMI > 15)]. Blood pressure change patterns were compared using repeated measures analysis of variance. Results: Systolic blood pressure in the high PLMI group was lower than that in the low PLMI group (p = 0.036). These results were also significant when adjusted for gender and age, but were not statistically significant when adjusted for BMI, alcohol, smoking, anti-hypertension medication use and sleep efficiency (p = 0.098). Systolic blood pressure dropped by 9.7 mm Hg in the low PLMI group, and systolic blood pressure in the high PLMI group dropped by 2.9 mm Hg. There was a significant difference in delta systolic blood pressure after sleep between the two groups in women when adjusted for age, BMI, alcohol, smoking, antihypertensive medication use and sleep efficiency (p = 0.023). Conclusion: PLMS was significantly associated with a decreasing pattern in nocturnal BP during sleep, and this association remained significant in women when adjusted for age, BMI, alcohol, smoking, antihypertension medication use and sleep efficiency related to blood pressure. We suggest that PLMS may be associated with cardiovascular morbidity.