The KickStrip: a novel testing device for periodic limb movement disorder

STUDY OBJECTIVES: In light of the ongoing debate over the clinical significance of periodic limb movement disorder (PLMD) and its monitoring in overnight sleep studies, we introduce a novel, portable, low-cost device for PLMD testing. The KickStrip is a disposable device, which includes a movement sensor, a central processing unit with real-time software, and a display. In the present study, the KickStrip final score (Kscore) is validated against the traditional periodic limb movement index (PLMI) based on overnight recordings in the sleep laboratory. DEISGN: Patients underwent full polysomnographic recordings concomitantly with the use of the KickStrip for a single night. SETTING: Sleep Disorders Unit at Loewenstein Rehabilitation Hospital and Sleep Medicine Center at Rambam Medical Center, Israel. PATIENTS: Eighty-two patients referred for overnight sleep recordings due to sleep disturbance of any kind. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The Kscores were collected and the PLMI computed for each leg separately. Pearson correlations between Kscores and PLMI ranged between r = 0.83 to r = 0.88 (p < 0.001). Sensitivity and specificity values of the Kscores for increasing PLMD thresholds showed sensitivity ranging from 50% to 100% and specificity ranging from 83% to 100%. Receiver operating characteristic curves showed area-under-the-curve values ranging from 82% to 92%. Bland-Altman plot showed high agreement between the methods. CONCLUSIONS: Comparisons between the Kscores and the traditional PLMI show increased accuracy with severity level and excellent agreement. The KickStrip is a valuable tool for PLMD testing for both clinical and research purposes.     

Exogenous melatonin in periodic limb movement disorder: an open clinical trial and a hypothesis

STUDY OBJECTIVES: The etiology of Periodic Limb Movement Disorder (PLMD) as well as the precise role of melatonin in human physiology remains poorly understood. Inspired by a single case observation we performed the presented study in order to obtain first evidence for the hypothesis that exogenous melatonin would decrease PLM's and thereby improves symptoms of PLMD patients. DESIGN: N/A. SETTING: N/A. PATIENTS/PARTICIPANTS: Nine patients with first time diagnosis of PLMD without RLS were treated over a six-week period with 3 mg melatonin, taken between 10 and 11 p.m. INTERVENTIONS: N/A. RESULTS: Melatonin improved well-being in 7 of the 9 patients. Polysomnography, performed prior and at the end of melatonin treatment, demonstrated a significant reduction of investigated movement parameters, such as PLMs, PLM index, PLMs with arousals and PLM-arousal index. Actigraphy, measured over 14 nights prior and during the last 14 days of melatonin treatment, showed a significant reduction in movement rate and minutes with movements during Time in Bed. CONCLUSIONS: The temporal distribution of PLMs, as well as the coupling of PLMs with the phase position of circadian temperature curve, suggest an involvement of the circadian timing system in the pathophysiology of PLMD. Locomotor activity in animals clearly exhibits a circadian pattern and can be strongly influenced by exogenous melatonin. Results suggest a chronobiotic effect of exogenous melatonin in PLMD. More specifically, we hypothesize that the mode of action of melatonin in the presented PLMD patients might have been an increase of output-amplitude of the circadian timing system, thereby enhancing the circadian rhythmicity of locomotor activity with a reduction of sleep motor activity.     

Practice parameters for the dopaminergic treatment of restless legs syndrome and periodic limb movement disorder

Dopaminergic agents, particularly dopamine agonists, have been used with increasing frequency in the treatment of restless legs syndrome and periodic limb movement disorder. These evidence-based practice parameters are complementary to the Practice Parameters for the Treatment of Restless Legs Syndrome and Periodic Limb Movement Disorder, published in 1999. These practice parameters were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. Recommendations are based on the accompanying comprehensive review of the medical literature regarding the dopaminergic treatment of restless legs syndrome (RLS) and periodic limb movement disorder (PLMD), which was developed by a task force commissioned by the American Academy of Sleep Medicine. The following recommendations serve as a guide to the appropriate use of dopaminergic agents in the treatment of RLS and PLMD. Levodopa with decarboxylase inhibitor, and the dopaminergic agonists pergolide, pramipexole, and ropinirole are effective in the treatment of RLS and PLMD. Other dopamine agonists (talipexole, cabergoline, piribidel, and alpha-dihydroergocryptine) and the dopaminergic agents amantadine and selegiline may be effective in the treatment of RLS and PLMD, but the level of effectiveness of these medications is not currently established. Lastly, no specific recommendations can be made regarding dopaminergic treatment of children or pregnant women with RLS or PLMD.     

An update on the dopaminergic treatment of restless legs syndrome and periodic limb movement disorder

This paper reviews evidence from April, 1998 through April 2002 for the dopaminergic treatment of the restless legs syndrome (RLS) and periodic limb movement disorder (PLMD). There has been increased study of dopaminergic agents for the treatment of these conditions since publication of a review paper and practice parameters that covered all types of medical treatment of RLS and PLMD in 1999. For this reason, the Restless Legs Syndrome Task Force and the Standards of Practice Committee decided to update the evidence on dopaminergic treatment of these conditions. This paper reviews the literature on levodopa, dopaminergic agonists (pergolide, pramipexole, ropinirole, talipexole, cabergoline, piribidel, DHEC), and other dopaminergic agents (amantadine, selegiline).     

Cognitive and behavioral anomalies among insomnia patients with mixed restless legs and periodic limb movement disorder

This study examined whether patients who have periodic limb movement disorder (PLMD), with or without comorbid restless legs syndrome (RLS), display the sleep-disruptive cognitive and behavioral anomalies found among primary insomnia sufferers. Archival data from a Sleep History Questionnaire, home-based polysomnography, and a sleep log were obtained for matched RLS/PLMD, primary insomnia, and noncomplaining volunteer samples. Statistical comparisons showed that the RLS/PLMD and primary insomnia samples differed significantly from the normal sleepers in regard to their propensities for certain sleep disruptive habits, perceived difficulties controlling pre-sleep cognitive activity, and their subjective sleep appraisals. These findings suggest RLS/PLMD patients display many of the cognitive and behavioral anomalies thought to perpetuate primary insomnia. Hence, behavioral interventions may be warranted for RLS/PLMD patients.     

The treatment of restless legs syndrome and periodic limb movement disorder. An American Academy of Sleep Medicine Review

A task force consisting of six authors reviewed the published literature on the therapy of the restless legs syndrome or periodic limb movements in sleep available in indices through April, 1998. They selected the 45 articles for detailed review which presented original investigations of therapeutic impact on the restless legs syndrome (RLS) or periodic limb movements (PLM) and which met minimal standards. These articles dealt with a range of pharmacological and other treatment modalities, although most dealt with medications and almost half of those concentrated on dopaminergic agents, especially levodopa in various formulations. Almost half of the articles reviewed used controlled methodologies, most commonly cross-over methodologies with randomized allocation of subjects. Multi-center studies with large numbers of subjects and long-term controlled studies were not found. Information was extracted from the articles and study design, clinical definition, evaluative measures, side effects, and outcomes were tabulated in 6 evidence tables and summarized in the accompanying text. This literature was evaluated for the nature of the studies performed and its coverage of potential therapies. The review concludes with comments on possible future directions for therapeutic investigation based on the current state of the literature.     

Differential rates of psychopathology symptoms in periodic limb movement disorder, obstructive sleep apnea, psychophysiological insomnia, and insomnia with psychiatric disorder.

STUDY OBJECTIVE: To determine patterns and relative intensity of psychopathology, as measured by the Minnesota Multiphasic Personality Inventory (MMPI), in 108 patients with either psychophysiological insomnia (PI; n=20), insomnia with psychiatric disorder (IPD; n=30), periodic limb movement disorder (PLM; n=28), or obstructive sleep apnea (OSA; n=30). DESIGN: Cross-sectional. SETTING: University sleep disorders center. MEASUREMENTS AND RESULTS: Subjects completed the MMPI prior to overnight diagnostic polysomnographic assessment followed by Multiple Sleep Latency Test (MSLT). Seventy five percent of the entire sample had at least one MMPI elevation (T>70). Groups showed significant baseline differences in age, BMI, and MSLT latency (all ps<.05). Logistic regression indicated that even after statistically controlling for these three diagnostic covariates, MMPI elevation was more likely among PLM and IPD patients than OSA or PI patients (all ps<.05). Followup pairwise comparisons indicated that this same pattern of group differences occurred for the Depression, Psychasthenia, and Schizophrenia scales (all ps<.05). CONCLUSIONS: Irrespective of age, obesity, and daytime sleepiness, patients with untreated PLM or IPD are more likely to experience clinically significant psychological difficulties than those with either OSA or PI. These differences are most likely to be manifested in terms of depressive symptoms, anxiety symptoms (tension, worry, guilt), social alienation, and diminished mental concentration. Finally, PLM may be associated with greater MMPI elevations than previously suspected, and agree with earlier clinical reports of high rates of psychiatric treatment in PLM.     

Periodic limb movement disorder of sleep in children

To characterize periodic limb movement disorder (PLMD) in a cohort of prepubertal children we examined sleep-related identifiable differences between children with PLMD and attention-deficit/hyperactivity disorder (ADHD), PLMD alone, and age-matched controls. Children were selected from a chart review of all children referred to a pediatric sleep medicine center and from a community survey of 5-7-year-old-children. Polysomnography (PSG) and parental report data from all children identified as having periodic limb movement index (PLMI) >5 were reviewed and compared with a cohort of age-matched controls. A total of 8.4% of children in the clinic-referred sample, and 11.9% of the children recruited from the community had PLMI >5. Of those, 44.4% were identified as having ADHD. Children with PLMD had significantly lower percentage of rapid eye movement (REM) than control children (P < 0.001). Children in the PLMD/ADHD group had a significantly greater number of arousals associated with PLM (PLMa) than children with PLMD only (P < 0.05). While a relationship between ADHD and PLMD was observed, it was weaker than previous reports (Chervin, R. D. et al. Sleep, 2002; 25: 213; Chervin, R. D. and Archbold, K. H. Sleep, 2001; 24: 313; Picchietti et al. J. Child Neurol., 1999; 13: 588; Picchietti et al. Mov. Disord., 1999; 14: 1000; Picchietti and Walters Sleep, 1999; 22: 297). Children in the PLMD/ADHD group were more likely to have PLMas than were children with PLMD only. We postulate that rather than a direct relationship between ADHD and PLMD, this link may be mediated by the presence of reduced REM sleep and more importantly by the sleep fragmentation associated with PLM-induced arousals.     

Rhythmic movement disorder in sleep persisting into childhood and adulthood

STUDY OBJECTIVES: To evaluate the type, duration, and distribution of rhythmic movements in sleep stages in school-aged children and young adults; to find out if cases of rhythmic movement disorder persisting beyond infancy are associated with any daytime symptoms or psychopathology. DESIGN: All participants underwent neurologic examination, biochemical screening, electroencephalography, neuroimaging, overnight videopolysomnography, and psychologic examination. SETTING: Department of Neurology and Sleep Laboratory, 1st Medical Faculty, Charles University, Prague. PATIENTS OR PARTICIPANTS: Ten subjects referred to the sleep disorders center because of rhythmic movement disorder. Five males, 5 females; age range, 7-24 years; mean age 14.7 +/- 5.69 years. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Biochemical screening, electroencephalogram, and neuroimaging were unremarkable in all cases. According to duration, 2 types of rhythmic movements were observed on polysomnography: longer episodes appeared in wakefulness and in non-rapid eye movement stage 1 sleep, while shorter episodes (2-80 seconds) occurred during non-rapid eye movement stage 2, non-rapid eye movement stage 3-4, and rapid eye movement sleep. According to sleep-stage distribution, we defined (a) rhythmic movements prevailing in the first half of the night and in the morning hours, usually associated with wakefulness or superficial sleep; (b) rhythmic movements occurring throughout the night in all sleep stages; (c) rhythmic movements prevailing in the second half of the night and mainly associated with rapid eye movement sleep. Psychologic examination showed symptoms of the attention-deficit/hyperactivity disorder in 6 cases. CONCLUSIONS: According to our study, rhythmic movement disorder persisting beyond infancy may be connected with various daytime symptoms; a strong association between rhythmic movement disorder and attention-deficit/hyperactivity disorder was found in school-aged children. We speculate that pathogenetic mechanisms similar to those in attention-deficit/hyperactivity disorder are involved in rhythmic movement disorder or that symptoms of attention-deficit/hyperactivity disorder may be secondary to rhythmic movement disorder.     

Psychiatric diagnoses and behaviour problems from childhood to early adolescence in young people with severe intellectual disabilities

BACKGROUND: While general population studies indicate an increase in the rate of psychiatric disorder in adolescence, little is known about the course of mental health and behaviour problems between childhood and adolescence in young people with severe intellectual disabilities. METHOD: From a sample of 111 children with severe intellectual disability who had been identified from the registers of six special schools at 4-11 years of age, 82 were traced and reassessed 5 years later at the age of 11-17 years. Behaviour problems were assessed by means of parental interviews conducted in the family home and parent and teacher questionnaires. Parental reports of psychiatric diagnoses were checked against health records. RESULTS: With most behaviour problems, including aggression, destructive behaviour and self-injury, there was little difference in rates between the two assessment occasions. However, in spite of this overall pattern of stability, the rates of some behaviour problems, including overactivity, showed significant reductions between childhood and early adolescence. Persistence rates for most behaviour problems appeared comparable to those reported for similar behaviours in general population studies of children. There was no significant difference in the proportion of cases with psychiatric diagnoses between the two assessment occasions, although brief psychotic episodes emerged in three cases in adolescence. CONCLUSIONS: The findings suggest that the prevalence of mental health and behavioural problems in young people with severe learning disabilities remains relatively stable between childhood and adolescence, although some specific behaviour problems diminish. However, a small minority of children may develop severe psychiatric disorders in adolescence.     

抑郁患者选择性5-羟色胺再摄取抑制剂治疗与周期性肢体运动综合征

目的:考察选择性5-羟色胺再摄取抑制剂(selective serotonin reuptake inhibitor,SSRI)与抑郁患者的周期性肢体运动综合征(periodic limb movement syndrome,PLMS)的关系。方法:本研究是病例回顾性分析,来自广东省精神卫生研究所的多导睡眠图(polysomnography,PSG)数据库(2006年11月-2009年11月)。选择了31例接受SSRI治疗的抑郁患者组(治疗组),并设定了2个对照组:27例未接受药物治疗抑郁患者组(未治疗组)和31例正常对照组。根据2007版美国睡眠研究会标准,判定了睡眠分期、睡眠相关事件和PLMS。结果:SSRI治疗组(13.7±2.6)比未治疗组(5.3±1.4)和正常对照组(4.1±1.1)的周期性肢体运动指数(periodic limb movement index,PLMI)更高(F=10.373,P0.001),而且治疗组的PLMS发生率(41.9%)明显高于其他两组(未治疗组:11.1%,正常对照组:6.5%,χ2=10.227,P0.001)。logistic回归显示的SSRI剂量越高(OR=1.107,1.036～1.184)、REM潜伏期越长(OR=1.289,1.176～1.413)和微觉醒越多(OR=1.483,1.219～1.748),接受SSRI的被治疗者就越容易出现PLMS。结论:选择性5-羟色胺再摄取抑制剂可能增加了抑郁患者出现周期性肢体运动综合征的风险,是一个值得临床学家重视的药源性副反应。     

A cross-sectional survey of upper and lower limb strength in boys and girls during childhood and adolescence

Changes in height and weight during childhood and adolescence are well documented, yet there is comparatively little comprehensive information about muscular development during this time. In a cross-sectional survey standing height, body weight and isometric strength of the elbow flexor and quadriceps muscles have been measured in 267 boys and 284 girls aged from 5 to 17 years. All the children were from private London schools. The mean heights and weights for each age group were between the 50th and 75th centiles for British children. The strength of both muscle groups in the boys and girls rose steadily in each age group from 8 to 12 years, after which there was a rapid increase in strength of both the quadriceps and elbow flexors in boys which continued even when growth in height and body weight had virtually ceased. In the pre-adolescent phase of growth, muscle strength of the elbow flexors and quadriceps increased as a function of height squared and cubed respectively, suggesting that stretch as a result of elongation of the long bones, and for the quadriceps, loading, may be the primary stimuli during this phase. In the postpubertal phase some other stimulus, such as a direct action of hormones on the muscle, must be responsible for the continued increase in strength in the boys.     

Depressive symptomatology in childhood and adolescence

Antecedents of depressive symptomatology in childhood and adolescence were examined in a prospective longitudinal study of at-risk youth (n = 168) from families of lower socioeconomic status. Relations between family context factors, maternal depressive symptoms, and depressive symptoms in childhood and adolescence were examined, with a focus on early family relationship factors rarely available for analysis in longitudinal data sets. Results suggest the possibility of etiological differences between depressive symptoms in childhood and in adolescence. Depressive symptomatology in childhood was predicted by the overall family context. Cumulative effects of maternal depressive symptomatology, early care lacking in emotional supportiveness, abuse, and family stressors were observed. Depressive symptomatology in adolescence, on the other hand, was specifically associated with maternal depression and early care lacking in emotional supportiveness. Moreover, an intriguing sex difference emerged: maternal depressive symptomatology was strongly associated with depressive symptomatology in adolescence for females, but for males supportive early care appeared more relevant.     

Sudden death in childhood and adolescence

Sudden death in childhood and adolescence is fortunately rare. However, when it occurs, it can have a devastating effect on the family. Therefore, these cases should be thoroughly investigated, including a complete post mortem examination by a specialist in paediatric pathology. The aim is to identify the cause of death, and potentially prevent future deaths. This review will provide an overview of the epidemiology of sudden death in childhood and adolescence and will outline the wide range of causes of death identified. Certain aspects of the paediatric post mortem examination will be discussed, and will finish with a section on deaths in children with chronic medical conditions.     

Sudden death in childhood and adolescence

Sudden natural deaths of individuals between the ages of 2 and 20 years which occurred during a 20-year period were identified from mortuary records. Necropsy reports and histological sections were reviewed; 169 sudden natural deaths were identified amongst 1012 deaths in that age group. Ninety-two sudden deaths occurred to children with recognized disorders; congenital heart disease, asthma, and epilepsy were the commonest problems identified. Amongst the 77 deaths of apparently healthy children, infection was the most frequently recognized disease. Only 11 deaths were unexplained, comprising 1 per cent of the necropsy population or 6.5 per cent of sudden natural deaths, a much smaller proportion than pertains in infancy. Necropsy examination of children dying suddenly yields useful information.