Periodic limb movements in sleep and iron status in children

STUDY OBJECTIVES: To assess potential relationships between serum iron and ferritin levels and the severity of periodic limb movement in sleep (PLMS) in a pediatric population, and to evaluate the response to supplemental iron therapy. DESIGN: A prospective study of all consecutively diagnosed children with PLMS (periodic limb movement index [periodic limb movements per hour of total sleep time, [PLMI] > 5) who underwent overnight polysomnographic evaluation. In all patients, complete blood count and serum iron and ferritin levels were obtained. Patients with serum ferritin concentrations less than 50 microg/L were prescribed iron sulfate at 3 mg/kg of elemental iron per day for 3 months. At the end of treatment, serum iron and ferritin levels and sleep studies were repeated. SETTING: Comprehensive Sleep Medicine Center, Tulane University Health Sciences Center, and Kosair Children's Hospital Sleep Medicine and Apnea Center. PATIENTS: Twenty boys and 19 girls with PLMS with a mean age of 7.5 +/- 3.1 years. INTERVENTION: Iron therapy. RESULTS: Twenty-eight (71.8%) patients had ferritin levels less than 50 microg/L. There was no significant correlation between serum ferritin concentration and PLMS severity as indicated by the PLMI (r = -0.19). The PLMI in patients with serum ferritin levels less than 50 microg/L (29.9 +/- 15.5 PLM/h) was higher than in patients with serum ferritin levels greater than 50 microg/L (21.9 +/- 11.8 PLM/h); however, the difference did not achieve statistical significance (P = 0.09). In contrast, serum iron was significantly correlated with PLMI (r = -0.43, P < 0.01). Indeed, patients with serum iron concentrations less than 50 microg/dL had a higher PLMI compared to patients with serum iron concentrations greater than 50 microg/dL (42.8 +/- 18.3 PLM/h and 23.1 +/- 10.1 PLM/h, respectively; P = 0.02). Twenty-five out of the 28 PLMS patients with serum ferritin levels less than 50 microg/L received treatment with iron sulfate, and 19 (76%) responded favorably. Among the responders to iron therapy, PLMI decreased from 27.6 +/- 14.9 PLM per hour to 12.6 +/- 5.3 PLM per hour after 3 months of iron supplements (P < 0.001) and coincided with increases in serum ferritin levels (pre: 40.8 +/- 27.4 microg/L vs post: 74.1 +/- 13.0 microg/L; P < 0.001). CONCLUSIONS: In children, the presence of PLMS is frequently associated with low serum iron and a tendency toward low serum ferritin levels. In addition, iron therapy is associated with clinical improvement in most of these patients.     

The association of upper airway resistance with periodic limb movements

STUDY OBJECTIVES: We hypothesized that the upper airway resistance syndrome (UARS), the component event being a respiratory effort related arousal (RERA), and periodic limb movements in sleep (PLMS), the component event being repetitive, stereotyped extremity movements occurring in a periodic fashion, were associated in certain patients. DESIGN: Invasive polysomnography using Pes and full facemask pneumotachography was used to identify RERA's in patients. Periodic limb movements (PLM) were scored according to standard criteria and as associated with RERA if the movement occurred between the Pes nadir and the onset of the arousal. SETTING: A university hospital Sleep Disorders Laboratory. PARTICIPANTS: Patients consecutively diagnosed with PLMS in our sleep disorders laboratory over a 1 year period. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Fourteen of twenty patients demonstrated UARS in addition to PLMS (70%). In those 14, 63% of RERAs were associated with a PLM (mean = 51.7 + 36.2 PLM/RERAs per study vs 5.6 + 6.3 PLM/RERAs per study if the association were random). Patients with UARS had more arousals with their PLMs (P = 0.0006). CONCLUSIONS: An association exists between PLMS and UARS on both a group level and an event level. A high percentage of PLM with arousals correlated with breathing events due to increased effort in UARS; this may be of clinical utility in the management of PLMS patients.     

Sleep pressure score: a new index of sleep disruption in snoring children

STUDY OBJECTIVES: Excessive daytime sleepiness (EDS), as measured by objective criteria, is infrequent in snoring children despite a high prevalence of EDS-related behavioral manifestations. We hypothesized that sleep architecture and arousal indexes may be altered relative to the severity of sleep-disordered breathing (SDB). DESIGN: Retrospective and prospective study. SETTING: Questionnaires were distributed through sleep clinic or school program; polysomnograms were performed at Kosair Children's Hospital in Louisville, Kentucky. PARTICIPANTS: To examine this issue, 182 children with SDB, 163 children with primary snoring, and 214 control children with a mean age of 6.9 +/- 2.6 years underwent polysomnographic evaluation in the laboratory. MEASUREMENTS AND RESULTS: Significant increases in slow-wave sleep (percentage of total sleep time) and decreases in rapid eye movement sleep (percentage of total sleep time) occurred in the SDB group (P < .0001). Spontaneous and respiratory arousal indexes and the apnea-hypopnea index (AHI) displayed negative and positive correlations, respectively, suggesting reciprocal interactions. Based on these observations, a sleep pressure score (SPS) was derived as a surrogate numeric measure for disrupted sleep homeostasis. The SPS exhibited linear increases relative to AHI, reaching a plateau at an AHI of 30 to 40 per hour of total sleep time. Furthermore, SPS values were significantly higher among African American and obese children (P < .0001). CONCLUSIONS: Sleep architecture is not preserved in children with SDB. An algorithm allowing for calculation of sleep propensity and disturbed sleep homeostasis in children who snore is proposed and may be of practical value in the assessment of sleepiness.     

Periodic Limb Movement During Sleep is Associated with Nocturnal Hypertension in Children

Background:

Increasing evidence suggests that blood pressure (BP) is significantly influenced by sleep problems in children, but the association between periodic limb movement during sleep (PLMS) and BP is still unclear. This study aims to compare ambulatory blood pressure (ABP) in children with and without PLMS.

Methods and Results:

A cross-sectional study involving 314 children (mean (SD) age of 10.4 (1.7) years, boys 62.4%). Participants underwent an overnight polysomnographic study and ABP monitoring. Subjects were hypertensive if mean SBP or DBP > 95th percentile and prehypertensive if mean SBP or DBP > 90^th percentile of reference. Children with PLMS (n = 17) were at significantly higher risk for nocturnal systolic (adjusted OR (95%CI) = 6.25 [1.87-20.88]) and diastolic (OR (95%CI) = 4.83 [1.66-14.07]) hypertension. However, mean nocturnal BP did not differ between children with and without PLMS. There was a trend for higher daytime BP in patients with PLMS than those children without PLMS (P = 0.084 for systolic BP z score; P = 0.051 for diastolic BP z score; P = 0.067 for systolic prehypertension). There were significant associations between log transformed PLM index and daytime systolic and mean BP z scores (P = 0.03 and 0.033 respectively) as well as that between log transformed PLM related arousal index (PLMSArI) and nocturnal diastolic and mean BP (P = 0.008 and 0.038 respectively).

Conclusions:

PLMS was independently associated with a wide range of BP elevations, especially nocturnal indices. Future studies should examine the underlying pathophysiologic mechanisms and effects of PLMS treatment on BP.

Citation:

Wing YK; Zhang J; Ho CKW; Au CT; Li AM. Periodic limb movement during sleep is associated with nocturnal hypertension in children. SLEEP 2010;33(6):759-765.     

Periodic limb movements during sleep: population prevalence, clinical correlates, and racial differences

STUDY OBJECTIVE: There is growing interest in the study of periodic limb movements during sleep and their potential clinical correlates. The aim of the present analysis is to address the lack of population-based studies using polysomnographic (PSG) measures to determine the prevalence of period limb movements during sleep in specific racial groups as well as the general population. SETTINGS AND PARTICIPANTS: A community-based sample of 592 participants drawn from the general population of tricounty Detroit (mean age = 41.9 +/- 12.6 years; 52.9% F; 31.5% African American). All individuals were assessed using objective and subjective measures in the sleep laboratory. MEASUREMENTS: Participants were evaluated during a 24-h laboratory assessment, including a polysomnogram and multiple sleep latency test. Periodic leg movements were scored using standard criteria. Reports of sleep disturbance and daytime sleepiness were also assessed using standardized measures including the Global Sleep Assessment Questionnaire (GSAQ) and the Epworth Sleepiness Scale (ESS). RESULTS: The overall prevalence of periodic limb movements during sleep (PLMSI >15) was 7.6%. African Americans had a lower prevalence of PLMSI >15 than Caucasians (4.3% vs. 9.3%; chi2= 4.5, P < 0.05). Regardless of race, symptoms of insomnia were significantly higher in individuals with PLMSI >15 than in those with PLMSI < or =15 (45% vs. 25%; chi2= 6.84, P < 0.01). CONCLUSION: This is the first study to determine the prevalence of PLMS in a population-based sample using standardized objective criteria. A key finding of the present study is that racial differences in this PSG parameter do exist, with African Americans being less likely to have elevated PLMS.     

Change in periodic limb movement index during treatment of obstructive sleep apnea with continuous positive airway pressure

STUDY OBJECTIVES: The following hypotheses were investigated: 1) severe obstructive sleep apnea (OSA) can mask concurrent periodic limb movement (PLM) disorder (PLMD), which becomes evident or worsens after treatment with continuous positive airway pressure (CPAP); 2) in patients with mild OSA, PLMs are not masked but may be triggered by subclinical hypopneas or respiratory effort-related arousals and improve after CPAP. DESIGN: Retrospective analysis was performed on 2 polysomnographic studies per patient--1 baseline, the second with CPAP titration. The apnea-hypopnea index (AHI) and PLM index (PLMI) under the 2 conditions were statistically analyzed. SETTING: University hospital sleep disorders center. PATIENTS: Patients were selected if they had a baseline AHI of 5 or greater and CPAP titration resulted in reduced AHI. Also, each needed to have either a PLMI of 5 or greater on baseline PSG or during CPAP titration. Patients who started or discontinued a medication that could affect PLMs after the baseline PSG were excluded. INTERVENTIONS: As clinically indicated, CPAP for OSA. MEASUREMENTS AND RESULTS: Eighty-six patients qualified and were divided into 3 groups based on OSA severity. Significant correlations (P < 0.05) were found between AHI and PLMI on the baseline PSG (-0.50), between AHI on baseline PSG and PLMI on CPAP titration (0.49), and between PLMI on baseline PSG and on CPAP titration (-0.21). The increase in PLMI during CPAP titration in patients with severe OSA was statistically significant (P < 0.001). The PLMI decreased with CPAP in 20 of 86 patients, mostly in the mild OSA subgroup. Regression of post-CPAP reduction of AHI and change in PLMI yielded a significant logarithmic relationship (R2 = 0.3042). CONCLUSIONS: Severity of OSA may determine the effect of CPAP on PLMs. The PLMs may increase in moderate to severe OSA due mainly to "unmasking" of underlying PLMD. The PLMs may decrease in mild OSA post-CPAP due to resolution of PLMs associated with respiratory effort-related arousals. This suggests that PLMs may have more than 1 etiology and may be categorized as spontaneous (as in PLMD) and induced (when secondary to respiratory effort-related arousals).     

Medikamentöse Therapie des Restless-legs-Syndroms

The aim of restless legs syndrome (RLS) therapy is a reduction of RLS symptoms, including the urge to move and unpleasant sensations in the legs, the associated sleep disturbances, and ultimately daytime impairment. Of particular importance are the periodic leg or limb movements during sleep (PLMS), which regularly occur in patients with significant RLS symptoms, lead to sleep fragmentation, and are a significant cause of sleep disturbance in RLS. PLMS are then clinically relevant if they lead to arousal, which is typically the case with RLS. It may be cortical arousal, which may be identified by typical EEG changes in polysomnography or with autonomic arousal as heart rate or blood pressure changes. In addition, PLM can also lead to complete awakenings. The indication for therapy arises from the subjective suffering, in particular the extent of the urge to move and sleep disorders.     

Cardiovascular Variability During Periodic Leg Movements in Sleep in Children

Study Objectives:

Periodic leg movements in sleep (PLMS) are episodes of repetitive and stereotypic leg movements occurring during sleep. In adults, research indicates that PLMS affects sleep quality and duration and are associated with a shift to relatively greater sympathetic influence over cardiovascular variables. However, little research has been performed to investigate the effect of PLMS episodes on cardiac autonomic control in children. This study aimed to quantify the effect of PLMS episodes during NREM2 sleep on heart rate variability (HRV) measures of sympathovagal balance in children.

Participants:

Overnight polysomnography data from 20 children (7–12 y) referred for assessment of sleep disordered breathing (SDB) were analyzed retrospectively. Ten children with episodes of PLMS were matched for age and SDB severity with a control group of 10 children without PLMS episodes.

Results:

The LF/HF ratio was significantly higher in the PLM+ compared with both the PLM− periods from PLMS subjects (P < 0.001) and the periods from the control group (P < 0.001). However, this effect could not be parsimoniously interpreted due to the likelihood that leg movements had a direct effect on the lower frequencies. Analysis of the ratio PLM+ to PLM+ plus PLM− indicated parasympathetic inhibition during periods of periodic leg movement and the onset of individual leg movements were associated with cardiac acceleration followed by a return to pre-movement levels.

Conclusion:

This study identified vagal inhibition in association with episodes of PLMS in children. Rapid cardiac acceleration occurring concurrently with the onset of individual leg movements also suggested decreased vagal activity associated with the movements.

Citation:

Walter LM; Foster AM; Patterson RR; Anderson V; Davey MJ; Nixon GM; Trinder J; Walker AM; Horne RSC. Cardiovascular variability during periodic leg movements in sleep in children. SLEEP 2009;32(8):1093-1099.     

Gender-related differences in symptoms of patients with suspected breathing disorders in sleep: a clinical population study using the sleep disorders questionnaire

BACKGROUND: Gender-related differences in the symptom profile of patients with suspected sleep disordered breathing (SDB) may be one explanation of the clinical underrecognition of SDB in women. STUDY OBJECTIVES: The aim of this study was to prospectively assess gender-related differences in presenting symptoms in a clinical sample of patients with suspected sleep disordered breathing. DESIGN: Administration of the Sleep Disorders Questionnaire prior to clinical and polysomnographic evaluation. Responses obtained from the questionnaire were used to construct 4 independent symptom scales: sleep apnea (SA), periodic limb movement syndrome (PLM), psychiatric sleep disorder (PSY), and narcolepsy (NAR). Analyses of variance were used to examine the effect of gender, AHI, and age on the symptom scales. Associations between gender and each diagnostic scale of the questionnaire were determined by multiple analyses of covariance. SETTING: Tertiary pulmonary referral center. PARTICIPANTS: 2739 men and 782 women with suspected SDB. All patients who were referred to the sleep laboratory underwent full-night polysomnography, irrespective of the likelihood of SDB. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Overall, men scored significantly higher on items related to worsening of snoring/breathing with alcohol (P < 0.001) and smoking history (P < 0.01) than women. Complaints such as witnessed apneas (P < 0.001) and worsening of snoring in supine position (P < 0.05), however, were more frequently reported by men with an apnea-hypopnea index (AHI) < 5/hr, compared with AHI-matched women. There were no significant differences in these items in patients with an AHI > 15/hr. In contrast, women complained significantly more often of insomnia, restless legs, depression, nightmares, palpitations at night, and hallucinations than men. As a result, women had significantly higher scores on the PLM, PSY, and NAR scales of the Sleep Disorders Questionnaire (P < 0.001, for all). After adjustments for age, body mass index, AHI, arousal index, oxygen saturation data, and smoking history, by means of multiple analyses of covariances, gender differences remained significant (P < 0.001, for all scales). CONCLUSIONS: We observed significant gender-related differences in presenting symptoms of patients with sleep disordered breathing at a tertiary level. These differences should be taken into consideration in clinical evaluation of women with suspected sleep disordered breathing.     

Variability of periodic leg movements in various sleep disorders: implications for clinical and pathophysiologic studies

STUDY OBJECTIVES: 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. DESIGN: Retrospective observational study. SETTING: Data collection occurred in the sleep disorders unit. PATIENTS: 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. INTERVENTIONS: N/A. RESULTS: 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. CONCLUSIONS: 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.     

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.     

Sleep disorders in Taiwanese children with attention deficit/hyperactivity disorder

To assess obstructive sleep apnea syndrome (OSAS) and periodic limb movement disorder (PLMD) in children with attention deficit/hyperactivity disorder (ADHD) compared with a control group. The ADHD was diagnosed based on Diagnostic and Statistical Manual, version IV (DSM-IV) criteria on successively seen elementary school children aged 6-12 years referred to a psychiatric clinic for suspected ADHD. A standardized interview (Kiddie-SADS-E), parents and teacher questionnaires, neuropsychological testing, and nocturnal polysomnography were completed for each child. Eighty-eight children (77 boys) with ADHD and 27 controls were involved in the study. Fifty children with ADHD (56.8%) had an apnea-hypopnea index (AHI) >1 event h(-1) and 17 (19.3%) had an AHI >5 event h(-1). Nine children (10.2%) had a periodic limb movement index (PLMI) >5 events h(-1). There is one child with AHI >1 and none with a PLMI > 5 in the control group. In the test of variables of attention (TOVA), the response time was significantly worse in ADHD with sleep disorders than those without them. The child behavior checklist (CBCL) showed a significant difference between groups in the hyperactivity subscale. The diagnostic criteria for ADHD based on DSM-IV do not differentiate between children with or without sleep disorders. Evaluation of sleep disorders should be considered before starting drug treatment for ADHD.     

Long-term follow-up of periodic limb movements in sleep in older adults

STUDY OBJECTIVES: The goal of this study was to examine the natural history of periodic limb movements in sleep (PLMS) in older adults. DESIGN: Prospective, longitudinal design. SETTING: San Diego area. PARTICIPANTS: Community-dwelling older adults. INTERVENTIONS: NA MEASUREMENTS AND RESULTS: Subjects participated in follow-up visits every few years. Sleep disorders were assessed at each visit using sleep questionnaires and overnight sleep recordings. Changes in PLMS over time were examined as well as variables that were associated with change. Average PLMS did not change over time, although there was considerable variability within the sample. In women, changes in PLMS were associated with changes in sleep-disordered breathing. This relationship was not found in men. CONCLUSIONS: Although the prevalence of PLMS is high for older adults, the severity of the disorder does not progressively worsen with increasing age.     

Validation of a Portable Monitoring System for the Diagnosis of Obstructive Sleep Apnea Syndrome

Study Objective:

To evaluate if a portable monitor could accurately measure the apnea-hypopnea index (AHI) in patients with a suspicion of obstructive sleep apnea (OSA).

Design:

Prospective and randomized.

Setting:

Sleep laboratory.

Participants:

80 participants: 70 patients with clinical OSA suspicion and 10 subjects without suspicion of OSA.

Interventions:

N/A

Measurements and Results:

Three-order randomized evaluations were performed: (1) STD (Stardust II) used at the participants'' home (STD home), (2) STD used simultaneously with PSG in the sleep lab (STD+PSG lab), and (3) PSG performed without the STD (PSG lab). Four AHI values were generated and analyzed: (a) STD home; (b) STD from STD+PSG lab; (c) PSG from STD+PSG (named PSG+STD lab); and (d) PSG lab. Two technicians, blinded to study details, performed the analyses of all evaluations. There was a strong correlation between AHI from the STD and PSG recordings for all 4 AHI values (all correlations above 0.87). Sensitivity, specificity, and positive and negative predictive values at AHI cut-off values of 5, 15, and 30 events/hour were calculated. AHI values from the PSG lab and PSG+STD lab were compared to STD home and STD+PSG lab and showed the best results when STD and PSG were performed simultaneously. In all analyses, the area under ROC curve was at least 0.90. With multiple comparisons, diagnostic agreement was between 91% and 75%. The Bland Altman analyses showed strong agreement between AHI values from the STD and PSG recordings, especially when comparing the AHI from simultaneous STD and PSG recordings.

Conclusion:

These data suggest that the STD is accurate in confirming the diagnosis of OSA where there is a suspicion of the disorder. Better agreement occurred during simultaneous recordings.

Citation:

Santos-Silva R; Sartori DE; Truksinas V; Truksinas E; Alonso FFFD; TufikS; Bittencourt LRA. Validation of a portable monitoring system for the diagnosis of obstructive sleep apnea syndrome. SLEEP 2009;32(5):629-639.     

Hyperactivity and polysomnographic findings in children evaluated for sleep-disordered breathing

STUDY OBJECTIVES: Children with sleep-disordered breathing (SDB) or periodic leg movements during sleep (PLMS) often have hyperactive behavior that improves when the sleep disorder is treated. Some children with SDB also have PLMS. To determine what polysomnographic features of SDB might be associated with hyperactive behavior, we studied behavior, SDB, and PLMS in a series of patients. DESIGN: Prospective and observational. SETTING: University-based sleep disorders laboratory. SUBJECTS: Children (n=113) aged 2 to 18 years, referred for suspected SDB. INTERVENTIONS: Parents completed the hyperactivity index of the Connors' Parental Rating Scale, and results were converted to age-adjusted t-scores. Children underwent laboratory-based polysomnography, with esophageal pressure monitoring when requested (n=19) by referring physicians. RESULTS: Children with SDB (n=59) showed high hyperactivity scores (mean 59.5+/-18.3 SD, 95% C.I. [54.7, 64.2]) but these scores were no higher than those of children without SDB (59.0+/-15.1, [54.8, 63.1]). Hyperactivity showed no significant associations with the rate of apneas and hypopneas, minimum oxygen saturation, or most negative esophageal pressure (p>0.10), but was associated with the presence of 5 or more PLMS per hour (p=0.02). The rate of PLMS showed a linear association with hyperactivity among those subjects with SDB (p = 0.002), but no association among those subjects without SDB (p = 0.64). CONCLUSIONS: These findings suggest that hyperactive behavior is common among children referred for suspected SDB, regardless of the presence or severity of SDB. Current observations cannot prove causality, but they are consistent with the hypothesis that PLMS may contribute to hyperactivity and SDB may act as an effect modifier.     

Patients with attention-deficit/hyperactivity disorder without observed apneic episodes in sleep or daytime sleepiness have normal sleep on polysomnography

STUDY OBJECTIVE: There is continuing speculation about the relationship between attention-deficit/hyperactivity disorder (ADHD) and obstructive sleep apnea (OSA) or periodic limb movement disorder (PLMD)/restless legs syndrome. The objective was to determine if a significant portion of children with ADHD diagnosed using DSM-IV criteria have OSA or PLMD. SETTING: Sleep disorders centers in a private practice setting and a hospital setting. PARTICIPANTS: Children aged 6 to 14 years with ADHD were enrolled. Patients with snoring were not excluded. Although patients with snoring plus either observed apneic episodes in sleep or excessive daytime sleepiness were to be excluded, as were patients with restless legs at night, only 1 subject actually had to be excluded because of these criteria. MEASUREMENTS AND RESULTS: Forty children were evaluated with a polysomnogram. A respiratory disturbance index cut-off of more than 5 per hour of sleep was used to diagnose OSA, and a periodic limb movement (with arousal) index cut-off of 5 or more per hour of sleep was used to diagnose PLMD. The Attention-Deficit/Hyperactivity Disorder Rating Scale-IV-Parent Version: Investigator Administered and Scored was used to determine severity of inattentive, hyperactive, and total ADHD symptoms. Except for a somewhat longer rapid eye movement sleep latency and decreased percentage of rapid eye movement sleep, polysomnography was essentially normal. No patient had OSA or PLMD on polysomnography. CONCLUSIONS: OSA or PLMD is not a common underlying disorder or etiologic factor in patients who meet the criteria for ADHD. In the absence of symptoms suggesting a primary sleep disorder, such as snoring with observed apneic episodes in sleep or daytime sleepiness or restless legs, polysomnographic evaluation does not seem indicated in patients with ADHD.     

The Utility of Single-Channel Nasal Airflow Pressure Transducer in the Diagnosis Of OSA at Home

Rationale:

Given the high prevalence of obstructive sleep apnea (OSA) and the demand on polysomnography (PSG), there is a need for low cost accurate simple diagnostic modalities that can be easily deployed in primary care to improve access to diagnosis.

Study Objectives:

The aim was to examine the utility of single-channel nasal airflow monitoring using a pressure transducer at home in patients with suspected OSA.

Design:

Cross-sectional study

Setting:

Laboratory and home

Participants:

The study was conducted in two populations. Consecutive patients with suspected OSA were recruited from the sleep disorders clinic at a tertiary referral center and from 6 local metropolitan primary care centers.

Interventions:

All patients answered questionnaires and had laboratory PSG. Nasal airflow was monitored for 3 consecutive nights at home in random order either before or after PSG.

Results:

A total of 193 patients participated (105 sleep clinic patients and 88 from primary care). The mean bias PSG apnea hypopnea index (AHI) minus nasal flow respiratory disturbance index (NF RDI) was –4.9 events per hour with limits of agreement (2 SD) of 27.8. NF RDI monitored over 3 nights had high accuracy for diagnosing both severe OSA (defined as PSG AHI > 30 events per hour) with area under the receiver operating characteristic curve (AUC) 0.92 (95% confidence interval (CI) 0.88-0.96) and any OSA (PSG AHI >5), AUC 0.87 (95% CI 0.80-0.94).

Conclusions:

Single-channel nasal airflow can be implemented as an accurate diagnostic tool for OSA at home in both primary care and sleep clinic populations.

Citation:

Makarie Rofail L; Wong KKH; Unger G; Marks GB; Grunstein RR. The utility of single-channel nasal airflow pressure transducer in the diagnosis of OSA at home. SLEEP 2010;33(8):1097-1105.     

Periodic limb movements in sleep in community-dwelling elderly.

The prevalence of periodic limb movements in sleep (PLMS) in a randomly selected elderly sample is reported. In San Diego, 427 elderly volunteers aged 65 yr and over were recorded in their homes. Forty-five percent had a myoclonus index, MI greater than or equal to 5. Correlates of PLMS included dissatisfaction with sleep, sleeping alone and reported kicking at night. Although statistically significant, the strengths of the associations between interview variables and myoclonus indices were all small. No combination of demographic variables and symptoms allowed highly reliable prediction of PLMS.     

Periodic leg movements during sleep and wakefulness in narcolepsy

The objectives of the study were to measure the prevalence of periodic leg movements during NREM and REM sleep (PLMS) and while awake (PLMW) and to assess the impact of PLMS on nocturnal sleep and daytime functioning in patients with narcolepsy. One hundred and sixty-nine patients with narcolepsy and 116 normal controls matched for age and gender were included. Narcoleptics with high and low PLMS indices were compared to assess the impact of PLMS on sleep and Multiple Sleep Latency Test (MSLT) variables. More narcoleptics than controls had a PLMS index greater than 5 per hour of sleep (67% versus 37%) and an index greater than 10 (53% versus 21%). PLMS indices were higher both in NREM and REM sleep in narcoleptic patients, but the between-group difference was greater for REM sleep. A significant increase of PLMS index was also found with aging in both narcoleptic patients and controls. PLMW indices were also significantly higher in narcoleptic patients. Patients with an elevated index of PLMS had a higher percentage of stage 1 sleep, a lower percentage of REM sleep, a lower REM efficiency and a shorter MSLT latency. The present study demonstrates a high frequency of PLMS and PLMW in narcolepsy, an association between the presence of PLMS and measures of REM sleep and daytime functioning disruption. These results suggest that PLMS represent an intrinsic feature of narcolepsy.     

Ropinirole decreases periodic leg movements and improves sleep parameters in patients with restless legs syndrome

STUDY OBJECTIVES: Polysomnographic study evaluating the efficacy of ropinirole for the treatment of patients with restless legs syndrome (RLS) suffering from periodic leg movements in sleep (PLMS). DESIGN: Double-blinded, placebo-controlled, parallel-group study. SETTING: 15 tertiary referral centers in the USA. Participants: 65 patients with RLS and PLMS. INTERVENTIONS: Ropinirole (0.25-4.0 mg per day) or placebo for 12 weeks. MEASUREMENTS AND RESULTS: Data from 59 patients were included in the primary endpoint analysis. PLMS per hour decreased more with ropinirole (48.5 to 11.8), compared with placebo (35.7 to 34.2; adjusted treatment difference: -27.2; 95% confidence interval [CI]: -39.1, -15.4; P < .0001). Periodic limb movements with arousal per hour decreased from 7.0 to 2.5 with ropinirole but increased from 4.2 to 6.0 with placebo (adjusted treatment difference: -4.3, 95% CI: -7.6, -1.1; P = .0096). Periodic limb movements while awake per hour decreased from 56.5 to 23.6 with ropinirole but increased from 46.6 to 56.1 with placebo (adjusted treatment difference: -39.5; 95% CI: -56.9, -22.1; P < .0001). Ropinirole treatment significantly improved patients' ability to initiate sleep (P < .05) and the amount of Stage 2 sleep compared with placebo (P < .001). There were also non-significant trends toward increases in total sleep time and sleep efficiency. Sleep adequacy (measured on the subjective Medical Outcomes Study sleep scale) was significantly improved with ropinirole treatment (adjusted treatment difference: 12.1; 95% CI: 1.1, 23.1; P = .0316). In contrast, the placebo group showed a greater increase in Stage 3/4 sleep (P < .01). No serious adverse events occurred in either group. CONCLUSIONS: Ropinirole is effective in the treatment of both the sleep and waking symptoms of RLS.