Depression is differently associated with sleep measurement in obstructive sleep apnea, restless leg syndrome and periodic limb movement disorder.

Depression causes sleep disturbance and is associated with various sleep-related disorders. However, how depression affects the symptomatic presentation of different sleep-related disorders is unclear. In this study, we investigated the sleep parameters of different sleep-related disorders between depressive and non-depressive patients. A total of 785 patients underwent polysomnography in a mental hospital from Jan 2012 to Jun 2013. We first analyzed variables between the depressive and non-depressive groups. The patients were then divided into four groups: obstructive sleep apnea (OSA, n = 339), restless leg syndrome (RLS, n = 51), periodic limb movement disorder (PLMD, n = 58) and comorbid group (OSA and RLS, n = 46). We next compared sleep measures between the depressive and non-depressive subjects within each groups. The patients with OSA and depression were significantly associated with a higher periodic limb movement index. Significantly more patients with RLS patients and depression had initial insomnia complaints. However, significantly more patients with PLMD and depression middle insomnia. Compared with non-depressive population, depressive patients had higher comorbidity with RLS and PLMD. Depression may have different association with the sleep parameters in different sleep-related disorders. Further investigations are needed to investigate how these findings may affect patients' awareness and clinicians' diagnosis and management of sleep-related disorders.

Neurocognitive and behavioral significance of periodic limb movements during sleep in adolescents with attention-deficit/hyperactivity disorder.

Study Objectives: The purpose of this study is to examine the association of abnormal periodic limb movements during sleep (PLMS) with neurocognitive and behavioral outcomes in adolescents with attention-deficit/hyperactivity disorder (ADHD) from the general population. Methods: Four hundred twenty-one adolescents (17.0 ± 2.3 years, 53.9% male) from the Penn State Child Cohort, a random general population sample, underwent 9 hr polysomnography, clinical history, physical examination, neurocognitive evaluation, and completed the Child or Adult Behavioral Checklist (C/ABCL). The presence of ADHD was ascertained by parent- or self-report of receiving a diagnosis of ADHD. PLMS were defined as a PLM index (PLMI) of ≥5 events per hour of sleep. Results: Adolescents with ADHD (n = 98) had a significantly higher PLMI (5.4 ± 7.3) and prevalence of PLMS (35%) when compared with controls (3.4 ± 5.6, p = 0.006 and 21%, p = 0.004). Significant interactions between ADHD and PLMS showed that adolescents with both disorders (n = 35) were characterized by deficits in control interference, as measured by Stroop test, and elevated internalizing behaviors, as measured by C/ABCL. ADHD severity and externalizing behaviors were elevated in a dose-response manner across ADHD-alone (n = 63) and ADHD + PLMS groups. The association of ADHD with other neurocognitive functions did not vary as a function of PLMS. Conclusions: PLMS are significantly more frequent in adolescents with ADHD. Importantly, adolescents with both disorders not only have worse neurobehavioral functioning than adolescents with ADHD-alone but specifically presented with executive deficits and anxiety symptoms. These data suggest that PLMS may be a marker of more severe underlying neurobiological deficits in adolescents with ADHD and comorbid internalizing problems.

Sleep-dependent motor sequence memory consolidation in individuals with periodic limb movements.

Periodic limb movements (PLMs) during sleep increase with age and are associated with striatal neurodegeneration and dopamine deficiency. Limb movements are often associated with disruptions to non-rapid eye movement (NREM) sleep. Motor skill memory consolidation recruits the striatum, and learning-dependent striatal activation is associated with NREM sleep. Therefore, we investigated whether de novo individuals who significantly experience elevated levels of PLMs but have not been formally diagnosed with periodic limb movement disorder had learning and sleep-related memory deficits and whether these deficits were related to sleep quality and symptom severity. In total, 14 adults with significantly elevated PLMs (PLM condition), 15 age-matched controls (CTRL), and 14 age-matched "disturbed" sleep (through induced leg movements) controls (CTRL-ES) participated. The participants were trained (PM) and retested (AM) on procedural motor sequence learning (MSL) and declarative paired associates memory tasks. Baseline sleep quality was significantly worse in PLM than in CTRL. Despite the continued presence of PLMs in the PLM condition on the experimental night, remarkably, sleep quality improved and arousals decreased, vs. baseline, and did not differ from CTRL. MSL was significantly slower in the PLM condition than in CTRL at training but surprisingly exhibited overnight performance gains, which correlated with reduced arousals. As predicted, CTRL but not CTRL-ES had overnight gains in MSL. Taken together, this suggests that in the PLM condition, sleep quality was normalized following MSL, where they derived the same benefit of sleep to procedural memory consolidation as in CTRL. Sleep did not benefit declarative memory. Although preliminary, these results suggest that MSL in individuals with PLMs may provide a benefit to sleep, which in turn may benefit memory consolidation.

A pilot study of the association between sleep disturbance in children with liver transplants and parent and family health-related quality of life.

OBJECTIVE: To investigate the relationship between sleep disturbance in children with liver transplants and parent and family health-related quality of life (HRQOL). METHOD: 47 parents of children with liver transplants completed measures of child sleep and family HRQOL. Relationships between sleep and HRQOL and differences in HRQOL between groups with scores above and below the cutoff on a pediatric sleep measure were examined. RESULTS: Parents endorsed higher rates of sleep-related breathing disorder (SRBD) and restless legs syndrome and periodic limb movements during sleep (RLS/PLMS) and lower HRQOL compared with published data. Significant correlations were found between SRBD and RLS/PLMS and HRQOL, and significant group differences in HRQOL were found between groups above and below the cutoff for behavior problems and RLS/PLMS. CONCLUSION: There are significant relationships between symptoms of SRBD and RLS/PLMS in children with liver transplants and family HRQOL. Behavior problems may account for these strong relationships.

Parent versus teacher report of daytime behavior in snoring children.

PURPOSE: Problematic behavior is widely reported in children with sleep-disordered breathing (SDB). Daytime behavior is an important component in the evaluation of clinical history in SDB; however, there is a reliance on parental report alone, and it is unclear whether reports by teachers will aid diagnosis. METHODS: We assessed sleep and behavior reported by both parents and teachers in 19 children with SDB and 27 non-snoring controls. All children were screened for prior diagnoses of other medical and/or behavior and learning disorders and underwent polysomnography and both parental and teacher assessment of behavior. RESULTS: Both parents and teachers report greater problematic behavior in SDB children, predominantly of an internalizing nature. Despite this consistency and moderate correlation between informants, the agreement between parent and teacher reports of individual child behavior was poor when assessed using Bland-Altman plots. CONCLUSIONS: Clinicians should be mindful that the behavioral history of a child being evaluated for SDB may vary depending on whether parent or teacher report is being discussed as this may influence clinical decision making.

Impaired driving simulation in patients with Periodic Limb Movement Disorder and patients with Obstructive Sleep Apnea Syndrome.

BACKGROUND: Excessive daytime sleepiness (EDS) is considered to be responsible for increased collision rate and impaired driving simulator performance in Obstructive Sleep Apnea Syndrome (OSAS) patients. Periodic Limb Movement Disorder (PLMD) patients also frequently report EDS and may also have impaired driving capacities. METHODS: PLMD patients (n=16), OSAS patients (n=18), and controls (n=16) performed a monotonous 25-min driving simulation task. Parameters for driving capacity were the slope of the standard deviation of the lane position, lapses of attention (LOA), and structural deviations. The severity of sleep disruption and the degree of subjective sleepiness were measured. RESULTS: Slope and LOA were significantly higher in patients than controls, pointing to a decreased driving performance. At start patients and controls had similar driving capacity. The PLMD and OSAS groups did not differ on any scale or simulation performance, although OSAS patients generally performed worse. Subjective sleepiness was higher in patients than controls, and correlated positively with driving simulator parameters. Severity of the disorder and performance were uncorrelated. CONCLUSION: PLMD and OSAS patients showed impaired performance in a simulated monotonous driving task. At start, patients and controls performed similarly, but patient performance decreased clearly with time, suggesting that decreased vigilance as a result of disturbed sleep is an important component of deteriorated simulated and, possibly, real driving performance.

Relationship between sleep problems and health-related quality of life among pediatric liver transplant recipients.

Among adult liver transplant recipients (LTRs), sleep disturbances and fatigue are common. Sleep problems following pediatric liver transplantation may contribute to daytime fatigue and lower health-related quality of life (HRQOL). The aim of this cross-sectional study was to determine the impact of sleep problems on the HRQOL of pediatric LTRs using validated measures. Participants included 47 LTRs. Mean age of the LTRs was 10.9 ± 4.6 years, and mean time since transplantation was 6.2 ± 3.9 years. The primary indication for transplantation was biliary atresia (51%). According to parent reports, pediatric transplant recipients had symptoms of sleep-disordered breathing, excessive daytime sleepiness, daytime behavior problems, and restless legs; 40.4% of parents and 43.8% of children reported significantly lower total HRQOL for the recipients. Age, time since transplantation, and health status were not significantly related to the quality of life. Hierarchical regression analyses revealed that the sleep-disordered breathing subscale of the Pediatric Sleep Questionnaire accounted for significant variance in parent-proxy reports on the Pediatric Quality of Life (PedsQL) summary scales measuring children's psychosocial health (R(2) = 0.36, P < 0.001), physical health (R(2) = 0.19, P = 0.004), and total HRQOL (R(2) = 0.35, P < 0.001). Also, the sleep-disordered breathing subscale accounted for significant variance in the child self-reported school functioning scale (R(2) = 0.18, P = 0.03). Clinically significant sleep problems were more common among children with low total HRQOL. In conclusion, sleep problems were common in this cohort of pediatric LTRs and predicted significant variance in HRQOL. Prospective larger scale studies are needed to assess factors that contribute to sleep difficulties and low HRQOL in this population. The detection and treatment of significant sleep problems may benefit the HRQOL of pediatric LTRs.

Clinical correlates of periodic limb movements in sleep in Parkinson's disease.

OBJECTIVE: The aim of the current study was to investigate the frequency of periodic limb movements in sleep (PLMS) in Parkinson's disease (PD) and their impact on nocturnal sleep and daytime functioning. METHODS: Forty-five PD patients (mean age 68.5 ± 8.7 years; 32 males) underwent one night of polysomnography (PSG). Clinical assessment and questionnaires evaluating sleep disturbance and quality of life (QoL) were completed. Patients were divided into two groups based on their PLMS index (PLMSI): PLMSI ≥ 15 (PLMS+) and PLMSI <15 (PLMS-). RESULTS: There were 26 (57.8%) PD patients in the PLMS+group and 19 (42.2%) patients in the PLMS-group. Subjective assessment revealed an association between PLMS+status and greater PD symptom severity, more subjective sleep disturbance, and decreased QoL. All patients showed poor sleep, and no significant group differences were detected on PSG measures. CONCLUSION: We observed that PLMS occurred frequently in PD and increased with more severe PD. Although PLMS did not affect objective sleep, it was associated with increased sleep complaints and reduced QoL. Overall, our findings support the association between PLMS and PD as well as the clinical relevance of sleep disturbances in PD.

Sleep disturbances and nocturnal agitation behaviors in older adults with dementia.

STUDY OBJECTIVES: To examine nighttime sleep patterns of persons with dementia showing nocturnal agitation behaviors and to determine whether restless legs syndrome (RLS), periodic limb movements in sleep (PLMS), and obstructive sleep apnea (OSA) are associated with nocturnal agitation behaviors. DESIGN: Cross-sectional. SETTING: General community. PARTICIPANTS: 59 participants with geriatrician-diagnosed dementia. Participants ages ranged from 66 to 88 years (mean age 79.1; SD 6.0). Mean Mini Mental State Examination (MMSE) score was 20.1 (SD 6.6). MMSE was used to measure baseline cognitive function and not for the diagnosis of dementia. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Sleep was measured by 2 nights of in-home, attended, portable polysomnography (PSG). Nocturnal agitation was measured over 3 additional nights using the Cohen-Mansfield Agitation Inventory modified for direct observations. Two experts independently and via consensus identified probable RLS. Total sleep time in participants was 5.6 h (SD 1.8 h). Mean periodic limb movements in sleep index (PLMI) was 15.29, and a high percentage (49%) had moderate to severe obstructive sleep apnea. Probable RLS was present in 24% of participants. Those with more severe cognitive impairment had longer sleep latency. Severe cognitive impairment, low apnea hypopnea index (AHI), and probable RLS were associated with nocturnal agitation behaviors (R(2) = 0.35, F(3,55) = 9.40, P < 0.001). CONCLUSIONS: It appears that probable RLS is associated with nocturnal agitation behaviors in persons with dementia, while OSA and PLMS are not. Further investigation is warranted to determine if treatment of RLS impacts nocturnal agitation behaviors in persons with dementia.

Identification of problems in functioning of people with sleep disorders in a clinical setting using the International Classification of Functioning Disability and Health (ICF) Checklist.

We conducted an explorative, cross-sectional, multi-centre study in order to identify the most common problems of people with any kind of (primary) sleep disorder in a clinical setting using the International Classification of Functioning, Disability and Health (ICF) as a frame of reference. Data were collected from patients using a structured face-to-face interview of 45-60 min duration. A case record form for health professionals containing the extended ICF Checklist, sociodemographic variables and disease-specific variables was used. The study centres collected data of 99 individuals with sleep disorders. The identified categories include 48 (32%) for body functions, 13 (9%) body structures, 55 (37%) activities and participation and 32 (22%) for environmental factors. 'Sleep functions' (100%) and 'energy and drive functions', respectively, (85%) were the most severely impaired second-level categories of body functions followed by 'attention functions' (78%) and 'temperament and personality functions' (77%). With regard to the component activities and participation, patients felt most restricted in the categories of 'watching' (e.g. TV) (82%), 'recreation and leisure' (75%) and 'carrying out daily routine' (74%). Within the component environmental factors the categories 'support of immediate family', 'health services, systems and policies' and 'products or substances for personal consumption [medication]' were the most important facilitators; 'time-related changes', 'light' and 'climate' were the most important barriers. The study identified a large variety of functional problems reflecting the complexity of sleep disorders. The ICF has the potential to provide a comprehensive framework for the description of functional health in individuals with sleep disorders in a clinical setting.

Association of intronic variants of the BTBD9 gene with Tourette syndrome.

OBJECTIVE: To test the association between Tourette syndrome (TS) and genetic variants in genomic loci MEIS1, MAP2K5/LBXCOR1, and BTBD9, for which genome-wide association studies in restless legs syndrome and periodic limb movements during sleep revealed common risk variants. DESIGN: Case-control association study. SETTING: Movement disorder clinic in Montreal. Subjects We typed 14 single-nucleotide polymorphisms spanning the 3 genomic loci in 298 TS trios, 322 TS cases (including 298 probands from the cohort of TS trios), and 290 control subjects. MAIN OUTCOME MEASURES: Clinical diagnosis of TS, obsessive-compulsive disorder, and attention-deficit disorder. RESULTS: The study provided 3 single-nucleotide polymorphisms within BTBD9 associated with TS (chi(2) = 8.02 [P = .005] for rs9357271), with the risk alleles for restless legs syndrome and periodic limb movements during sleep overrepresented in the TS cohort. We stratified our group of patients with TS according to presence or absence of obsessive-compulsive disorder and/or attention-deficit disorder and found that variants in BTBD9 were strongly associated with TS without obsessive-compulsive disorder (chi(2) = 12.95 [P < .001] for rs9357271). Furthermore, allele frequency of rs9357271 inversely correlated with severity of obsessive-compulsive disorder as measured by the Yale-Brown Obsessive Compulsive Scale score. CONCLUSION: Variants in BTBD9 that predispose to restless legs syndrome and periodic limb movements during sleep are also associated with TS, particularly TS without obsessive-compulsive disorder.

Parasomnias and movement disorders in children and adolescents.

Childhood parasomnias and movement disorders arise from a variety of etiologic factors. For some children, psychopathology plays a causal role in sleep disorders; in other cases, recurrent parasomnia episodes induce psychopathology. Current research reveals complex interconnections between sleep and mental health. As such, it is important that clinicians consider the impact psychiatric disorders have on childhood parasomnias. This article describes common parasomnias and movement disorders in children and adolescents, with emphasis on psychologic and behavioral comorbidities.

Sleep disorders and their association with laboratory pain sensitivity in temporomandibular joint disorder.

STUDY OBJECTIVES: We characterized sleep disorder rates in temporomandibular joint disorder (TMD) and evaluated possible associations between sleep disorders and laboratory measures of pain sensitivity. DESIGN: Research diagnostic examinations were conducted, followed by two consecutive overnight polysomnographic studies with morning and evening assessments of pain threshold. SETTING: Orofacial pain clinic and inpatient sleep research facility. PARTICIPANTS: Fifty-three patients meeting research diagnostic criteria for myofascial TMD. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: We determined sleep disorder diagnostic rates and conducted algometric measures of pressure pain threshold on the masseter and forearm. Heat pain threshold was measured on the forearm; 75% met self-report criteria for sleep bruxism, but only 17% met PSG criteria for active sleep bruxism. Two or more sleep disorders were diagnosed in 43% of patients. Insomnia disorder (36%) and sleep apnea (28.4%) demonstrated the highest frequencies. Primary insomnia (PI) (26%) comprised the largest subcategory of insomnia. Even after controlling for multiple potential confounds, PI was associated with reduced mechanical and thermal pain thresholds at all sites (P < 0.05). Conversely, the respiratory disturbance index was associated with increased mechanical pain thresholds on the forearm (P < 0.05). CONCLUSIONS: High rates of PI and sleep apnea highlight the need to refer TMD patients complaining of sleep disturbance for polysomnographic evaluation. The association of PI and hyperalgesia at a nonorofacial site suggests that PI may be linked with central sensitivity and could play an etiologic role in idiopathic pain disorders. The association between sleep disordered breathing and hypoalgesia requires further study and may provide novel insight into the complex interactions between sleep and pain-regulatory processes.

Comparison of sleep variables between chronic widespread musculoskeletal pain, insomnia, periodic leg movements syndrome and control subjects in a clinical sleep medicine practice.

BACKGROUND: Between 50% and 89% of chronic pain patients report unrefreshing sleep. The aim of this retrospective analysis was to compare the sleep of normal subjects with the sleep of a clinical population presenting musculoskeletal chronic widespread pain (CWP), psychophysiological insomnia and restless legs syndrome/periodic limb movements during sleep (RLS/PLMS) in order to identify sleep variables that may explain the poor sleep complaints of CWP patients. METHODS: Sleep data from 10 normal subjects and 37 patients (mean age 55+/-3 yo), matched for age and sex, were retrieved from our sleep data bank. Sub-analysis controlled for the effects of medication. RESULTS: In comparison to normal subjects, sleep duration was shorter in CWP patients (-71 min; p<0.01); sleep efficiency was significantly lower in CWP and insomnia patients (-10.1% and -11.1%, respectively; p<0.05). CWP and PLMS patients lost one non-rapid eye movement (REM) to REM sleep cycle (p<0.04). An intermediate level of PLM was observed during the sleep of CWP patients in comparison to normal subjects (8.8/h vs. 2.0/h) and PLMS patients (33/h). Regular use of non-narcotic analgesics did not seem to interfere with sleep variables. CONCLUSIONS: The sleep of middle-aged patients with CWP is comparable to that of insomnia patients. The moderate level of PLM during sleep suggests that such sensory motor activity needs to be evaluated in patients suffering from chronic pain.

Clinical, behavioural and polysomnographic correlates of cataplexy in patients with narcolepsy/cataplexy.

BACKGROUND: Cataplexy is the main motor symptom of narcolepsy/cataplexy and is considered a form of rapid eye movement (REM) sleep motor dyscontrol appearing during wakefulness and elicited by emotions. This study examined the relationship between the frequency of cataplectic attacks in patients with narcolepsy/cataplexy and (a) the clinical and behavioural characteristics of cataplectic attacks, including the emotional tone of trigger events, and (b) the polysomnographic characteristics of daytime sleepiness, nocturnal sleep structure and indices of motor disorders during sleep. METHODS: A consecutive series of 44 first-diagnosed drug-naive patients with narcolepsy/cataplexy, fulfilling the International Classification of Sleep Disorders, 2nd edition (ICSD-2) clinical and polysomnographic diagnostic criteria, were interviewed to estimate the frequency and clinical characteristics of cataplectic attacks and the occurrence of REM sleep behaviour disorder (RBD). All patients also underwent a video-polysomnographic recording to assess their sleep parameters and indices of altered motor control during sleep. RESULTS: Patients were divided into two groups on the basis of the frequency of cataplectic attacks, namely high-frequency (n=30) or low-frequency (n=14) depending on whether they estimated they had more or less than one attack per month. High-frequency patients (with a larger proportion of men) reported attacks more often affecting mainly the head, jaw and shoulder muscles and experienced more events among those listed as possible triggers of attacks. Sixty-one percent of patients reported RBD and 43% had an RBD episode at video-polysomnography regardless of the frequency of cataplectic attacks or gender. Lastly, the frequency of periodic leg movements (PLM) per hour was higher in men than women and increased with age. CONCLUSIONS: Patients with more than one cataplectic attack per month had more frequent involvement of head, jaw and shoulder muscles and were mainly men. The proportions of patients with clinically assessed RBD and an RBD episode documented by video-polysomnography, as well as conspicuous values of PLM per hour, are fairly consistent with those reported in recent small-group studies. Therefore, it seems legitimate to argue that RBD and PLM are nocturnal manifestations intrinsic to narcolepsy/cataplexy and that the gender-related differences in the frequency of attacks and the value of PLM per hour may be indicative of a larger difference in the clinical and polysomnographic characteristics of narcolepsy/cataplexy than hitherto suspected.

Sleep related rhythmic movement disorder revisited.

To classify sleep related rhythmic movement disorder (SRMD) based on clinical, polysomnographic and videometric evaluation in a predominantly adult population, twenty-four patients (four females) aged 11-67 years identified by polysomnography and videometry were classified for type of SRMD, its duration and frequency during wakefulness and in the different sleep stages. SRMD persisted unto child- and adulthood in all patients. SRMD is not restricted to sleep-wake transition, occurs most frequently in wake, stages NREM 1 and 2, but also in REM and slow wave sleep. Most patients have one form of SRMD, few have two forms in one night. Longest duration is in wakefulness. Duration does not differ from one sleep cycle to another. Sleep is not fragmented by SRMD, and sleep stages generally do not change when SRMD occurs. Only few patients have short awakenings after SRMD. In four patients with sleep apnea SRMD coincided frequently with the onset of the apnea related arousal. Two patients had a family history of SRMD. In contrast to the ICSD-2 SRMD seems to persist into adulthood frequently with male preponderance. Familial forms are rare. SRMD in the investigated population is always occurring during sleep, even if patients reported it to occur strictly at wake-sleep transition. Polysomnography is a useful method to uncover SRMD aggravated by other sleep disorders and allows insight in some aspects of the pathology of this disorder, which is not well understood. In the adult patients it is not associated with mental pathologies and can be triggered by sleep apnea.

Nightmares and oxygen desaturations: is sleep apnea related to heightened nightmare frequency?

In the 19th century, several authors held the view that nightmares are caused by oxygen shortage. The present study was designed to study nightmare frequency in patients with obstructive sleep apnea syndrome and its relationship to respiratory parameters. A brief questionnaire was administered to 323 patients with sleep apnea syndrome before their first laboratory night. The reduction in nightmare frequency in the sleep apnea group was explained by the reduced dream recall frequency. Despite some illustrative examples of a correlation between oxygen desaturation and dream content, the respiratory parameters as measures of sleep apnea syndrome severity did not correlate substantially with nightmare frequency. Psychiatric comorbidity and an intake of psychotropic medication were associated with heightened nightmare frequency in this sample. It must be concluded that the oxygen hypothesis did not play a major role in explaining the occurrence of nightmares. As this might be partly explained by adaptation to the nightly desaturation periods, it will be fruitful to apply experimental procedures that interrupt airflow during (rapid eye movement) REM sleep for short periods in a systematic way without the knowledge of the sleeper and to then study their effects on dream content. Some patients reported a correlation between daytime stressors and nightmares, which is in line with modern etiological models of nightmares.

Effects of periodic leg movements during sleep in middle-aged subjects without sleep complaints.

Recent reports have called into question the relevance of periodic leg movements during sleep disorder (PLMSD) as a specific clinical entity. Because periodic leg movement in sleep index (PLMSI) increases with age, it has become an important exclusion criterion in research on aging. However, it is unknown if PLMSI is related to sleep quality in middle-aged subjects without sleep complaints. The sleep of 70 healthy, middle-aged subjects (age 40 to 60 years) without sleep complaints was evaluated. Subjects were divided into two groups according to their PLMSI severity: (1) 43 subjects (28 women, 15 men) were in the low PLMSI group (<5) and (2) 22 subjects (9 women, 13 men) were in the high PLMSI group (>10). A significantly higher proportion of men than women showed PLMSI greater than 5. There was no significant effect of PLMSI severity group for polysomnographic sleep parameters. PLMSI exerted a small but significant effect on subjective sleep quality, especially in middle-aged men. These results raise questions about the relevance of PLMSI as a pathological index for middle-aged subjects without sleep complaints and support the notion that an increase in PLMSI may be part of the normal process of aging associated with the loss of dopaminergic function.

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

UNLABELLED: 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.