Periodic leg movements during sleep in the elderly

Measurements of behavioral quiescence in Caenorhabditis elegans

The nematode Caenorhabditis (C.) elegans, a long time work horse for behavioral genetic studies of locomotion, has recently been studied for quiescent behavior. Methods previously established for the study of C. elegans locomotion are not well-suited for the study of quiescent behavior. We describe in detail two computer vision approaches to distinguish quiescent from movement bouts focusing on the behavioral quiescence that occurs during fourth larval stage lethargus, a transition stage between the larva and the adult. The first is the frame subtraction method, which consists of subtraction of temporally adjacent images as a sensitive way to detect motion. The second, which is more computationally intensive, is the posture analysis method, which consists of analysis of the rate of local angle change of the animal's body. Quiescence measurements should be done continuously while minimizing sensory perturbation of the animal.

Periodic leg movements are associated with reduced sleep quality in older men: the MrOS Sleep Study

STUDY OBJECTIVES

Periodic limb movements in sleep (PLMS) are common in the elderly. A previous large polysomnographic (PSG) study examining the relationship of PLMS to sleep architecture and arousals from sleep in women found that leg movements were common in elderly women, and PLMS which were associated with EEG arousals had a strong and consistent association with markers of disturbed sleep. Since sleep differs in men and women, we now investigate the association between PLMS and PSG indices of sleep quality in a large community-based sample of older men.

DESIGN

Observational study, cross-sectional analyses.

SETTING

Six clinical sites participating in the Osteoporotic Fractures in Men (MrOS) Study.

PARTICIPANTS

2,872 older community-dwelling men (mean age 76.4 years) who completed in-home PSG from 2003-2005.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

In-home PSG was performed which included bilateral measurement of leg movements. The total number of leg movements per hour of sleep (PLMI) and the number of leg movements causing EEG-documented arousals per hour of sleep (PLMA) were computed. A PLMI ≥ 5 (70.8%) and PLMA ≥ 5 (27.4%) were both prevalent. Linear regression models were used to examine the relationship between PLMS as predictors and sleep architecture, arousal index, and sleep efficiency as outcomes. The highest quintiles of PLMI (≥ 65.1) and PLMA (≥ 6.8) showed the largest association with indices of sleep architecture; PLMA showed a larger magnitude of effect. After multivariate adjustment, participants with a higher PLMA had a small but significantly higher arousal index, lower sleep efficiency, higher percentages of stages 1 and 2 sleep, and lower percentages of stage 3-4 and REM sleep (p < 0.01). An increased PLMI was similarly associated with a higher arousal index, higher percentage of stage 2 sleep, and lower percentage of stage 3-4 (p < 0.0001), but not with an increase in stage 1, REM sleep, or sleep efficiency. Neither PLMI nor PMLA was associated with subjective sleepiness measured by the Epworth Sleepiness Scale.

CONCLUSIONS

This study demonstrated that periodic leg movements are very common in older community-dwelling men and regardless of associated arousals, are associated with evidence of lighter and more fragmented sleep.

Sleep measured by polysomnography in patients receiving high-dose chemotherapy for multiple myeloma prior to stem cell transplantation

PURPOSE/OBJECTIVES

To describe the objective sleep of patients receiving chemotherapy for multiple myeloma (MM) prior to stem cell transplantation.

DESIGN

A descriptive study with repeated measures.

SETTING

An international referral center in an urban area of the southern United States.

SAMPLE

A convenience sample of a subset of 12 patients with MM, recruited from a randomized, controlled trial.

METHODS

Objective sleep was assessed using two nights of polysomnography, one obtained before and one after a second cycle of high-dose chemotherapy prior to stem cell transplantation. Demographic and clinical data were obtained through a retrospective chart review.

MAIN RESEARCH VARIABLES

Objective sleep including sleep characteristics, sleep-related respiratory events, and periodic limb movements (PLMs) of sleep.

FINDINGS

Sleep was characterized by a relatively short sleep time, excessive time spent awake after the onset of sleep, and poor sleep efficiency (objective sleep quality). Patients spent more than the expected percent of time in non-rapid eye movement sleep and less in rapid eye movement sleep. Arterial oxyhemoglobin saturation nadirs reflected episodes of low arterial oxygen saturation. PLMs during sleep were in the mildly elevated range.

CONCLUSIONS

Findings suggest that patients had poor sleep efficiency (objective sleep quality) and were slightly better sleepers after receiving a second cycle of high-dose chemotherapy. A number of patients also demonstrated obstructive sleep apnea and frequent PLMs.

IMPLICATIONS FOR NURSING

Findings support the need for additional investigation of sleep in patients with MM, particularly poor sleep efficiency and PLMs. Improving sleep may improve quality of life by decreasing associated symptoms such as pain, fatigue, and depression.

KNOWLEDGE TRANSLATION

Oncology nurses should consider assessing patients with MM for insomnia symptoms, excessive daytime sleepiness, obstructive sleep apnea, and a history of jerking or kicking their legs when asleep. Those symptoms may suggest the need for additional investigation of a possible sleep disorder, which may negatively influence mood and function.

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.

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.

Can periodic limb movement disorder be diagnosed without polysomnography? A case-control study

OBJECTIVES

(1) To determine whether clinical information can predict the presence of periodic limb movement disorder (PLMD). (2) To examine whether clinical data correlate with PLMD severity.

METHODS

Sixty-one adult patients (48 males and 13 females, aged 55.1+/-14.1 years) with PLMD (without a clinical diagnosis of restless legs syndrome) were compared with 61 control patients without PLMD (43 males and 18 females, aged 49.6+/-16.1 years) in this case-control study. All patients completed a detailed questionnaire which included (1) demographics, (2) sleep complaints, (3) medical disorders, (4) use of medication, nicotine, and caffeine, and (5) history of nocturnal motor/sensory leg symptoms. All patients underwent standard polysomnography.

RESULTS

The PLMD and control groups were similar in the prevalence of insomnia, hypersomnia, diabetes, peripheral neurologic disorders, anemia, spinal disease, antidepressant medication use, smoking, caffeine intake, and leg pain. Compared with the control group, the PLMD group reported more leg kicks (28% vs. 5%, P<0.001) and more crawling or aching sensations in legs (28% vs. 11%, P=0.023). The logistic regression analysis showed that only age (P=0.044), leg kicks (odds ratio (OR) 12.70, 95% confidence interval (CI) 2.80-57.63, P=0.001), and crawling or aching in legs (OR 5.23, 95% CI 1.16-23.44, P=0.029) were significantly related to the presence of PLMD. The positive predictive value of leg kicks in the diagnosis of PLMD was 85% and the negative predictive value was 57%. Within the PLMD group, only age correlated positively with the PLM-index (r=0.47, P<0.001). Both the PLM-index and the PLM arousal-index were negatively correlated with sleep efficiency on polysomnography (P=0.005 and P=0.006, respectively).

CONCLUSIONS

Clinical data are not sufficiently predictive of the presence of PLMD to rule in or rule out the diagnosis. Polysomnography is required for establishing the diagnosis of PLMD in patients with insomnia or hypersomnia.

Different sleep characteristics in restless legs syndrome and periodic limb movement disorder

OBJECTIVE

Periodic limb movements in sleep (PLMS) may or may not be associated with restless legs syndrome (RLS). The number of PLMS is commonly used to assess the clinical severity and sleep quality of patients with RLS. It is still unclear whether the sleep disorder of periodic limb movement disorder (PLMD) is different from the sleep disorder in RLS.

METHODS

We compared the polysomnograms (PSGs) of 27 prospectively recruited RLS patients and 26 retrospectively recruited age- and sex-matched PLMD patients without RLS symptoms.

RESULTS

The PLM index and the index of arousal-associated PLMS (PLMAI) were significantly higher in PLMD, whereas the index of EEG arousals not associated with any sleep-related event was significantly higher in RLS. In PLMD patients, the PLMI correlated negatively with the percentage of PLMS associated with an arousal, whereas this correlation was positive in RLS patients. Further, RLS patients spent significantly more time in wake-after-sleep onset, had more rapid eye movement sleep (REM) and less sleep stage I.

CONCLUSIONS

We conclude that the sleep disorder in RLS differs from that in PLMD. Spontaneous, not PLM associated EEG arousals should be included in the assessment of the sleep structure of patients with RLS, particularly in studies concerned with drug-efficacy.

Sleep laboratory diagnosis of restless legs syndrome

Polysomnographic recordings and the Suggested Immobilization Test (SIT) are frequently used to support the clinical diagnosis of restless legs syndrome (RLS). The present study evaluated the discriminant power of 5 different parameters: (1) index of periodic leg movements during sleep (PLMS), (2) index of PLMS with an associated microarousal (PLMS-arousal), (3) index of PLM during nocturnal wakefulness (PLMW), (4) SIT PLM index and (5) mean subjective leg discomfort score during the SIT (SIT MDS) in 100 patients with idiopathic RLS and 50 healthy control subjects. Both groups differed significantly on each parameter studied. Furthermore, while the SIT PLM, the PLMS and the PLMS-arousal indices revealed a poor ability to discriminate patients from controls, the PLMW index and the MDS both showed high sensitivity (87 +/- 7 and 82 +/- 8, respectively) and specificity (80 +/- 11 and 84 +/- 10, respectively) for diagnosing RLS. The combination of these 2 parameters correctly classified 88% of all subjects with a sensitivity of 82% and a specificity of 100%.

Toward a better definition of the restless legs syndrome. The International Restless Legs Syndrome Study Group

A large International Restless Legs Syndrome (RLS) Study Group has been formed. As its first task, the group has taken upon itself the role of defining the clinical features of the RLS. As minimal criteria for diagnosis, the group proposes the following four features: (a) desire to move the extremities, often associated with paresthesias/dysesthesias; (b) motor restlessness; (c) worsening of symptoms at rest with at least temporary relief by activity, and (d) worsening of symptoms in the evening or night. Other features commonly seen in RLS include sleep disturbance, periodic limb movements in sleep and similar involuntary movements while awake, a normal neurological examination in the idiopathic form, a tendency for the symptoms to be worse in middle to older age, and, in some cases, a family history suggestive of an autosomal dominant mode of inheritance.

Nightly variation of periodic leg movements in sleep in middle aged and elderly individuals

This study investigated night-to-night variation in periodic leg movements in sleep (PLMS). PLMS are common in the elderly, but their mechanism and significance are not understood. Forty-five aged individuals (means = 69.7 years) were studied polysomnographically for 2 or 3 nights with surface electrodes placed above the anterior tibialis. Results indicated that PLMS varied considerably from night to night within individuals, though there was not a significant difference between nights for the entire group. Some evidence indicated that individuals with less severe sleep complaints showed greater nightly variation. The nightly variation in PLMS was over four times as large as the nightly variation in breathing disturbance in sleep, another condition common in the sleep of the aged. These data suggest that studies relating PLMS to other key variables (e.g. symptoms of disturbed sleep) should rely on multiple nights of data or, if single night data are used, be particularly careful to replicate findings across samples.