Periodic limb movements in patients with obstructive sleep apnea syndrome

Periodic limb movements in patients with suspected obstructive sleep apnea without comorbid conditions

Background

Periodic limb movement disorder (PLMD) and obstructive sleep apnea (OSA) are overlapping clinical syndromes with common risk factors. However, current literature has failed to establish a clear pathophysiological link between them. Thus, little is known about periodic limb movements (PLM) in otherwise healthy patients with suspected OSA.

Methods

We performed a retrospective analysis of 112 patients (age: 44.5 ± 12.0 years, 14.3% female) with suspected OSA who underwent full night polysomnography for the first time. Patients with chronic diseases of any kind, recent infections, malignancies, or daily or regular use of any type of medication were excluded. Group comparisons were made based on the severity of OSA (using the apnea hypopnea index, AHI) or the periodic limb movement index (PLMI).

Results

Both, PLMI and the total number of periodic limb movements during sleep (PLMS), showed a significant increase in patients with severe OSA. In addition, AHI and apnea index (AI) were significantly higher in patients with PLMI >15/h, with a similar trend for hypopnea index (HI) (p < 0.001, p < 0.001, and p > 0.05, respectively). PLMI was significantly positive correlated with AHI, AI, and HI (r = 0.392, p < 0.001; r = 0.361, p < 0.001; and r = 0.212, p < 0.05, respectively). Patients with PLMI >15/h were significantly older (p < 0.001). There was no significant association between body mass index (BMI) and PLMI >15/h.

Conclusion

We found a significant association between the severity of OSA and PLM in our study population with suspected OSA but without other comorbidities. PLMI and PLMS were significantly increased in patients with severe OSA. Future prospective studies with larger collectives should verify the presented results and should include mechanistic aspects in their evaluation.

The association of obstructive sleep apnea and behavioral insomnia in children ages 10 and under

STUDY OBJECTIVES

Behavioral insomnia of childhood (BIC) and obstructive sleep apnea (OSA) are highly prevalent conditions affecting 10%-20% and 1%-5% of children, respectively. Studies in adults and adolescents have suggested that comorbid insomnia and OSA may have distinct clinical characteristics. The association between the two conditions in the pediatric population has not been thoroughly investigated. This study aimed to examine the association between BIC and OSA in young children.

METHODS

Children, 6 months to 10 years old, referred to a sleep specialist and polysomnography at the Hadassah Medical Center between 2018 and 2021 were included in this retrospective analysis. We excluded children with chromosomal and craniofacial abnormalities, posttonsillectomy, or neurological impairment. BIC diagnosis was extracted from the electronic health records in accordance with the International Classification of Sleep Disorders, third edition criteria. OSA was diagnosed by polysomnography (apnea-hypopnea index > 2 events/h).

RESULTS

Of 312 children (age 4.42 ± 2.42 years), 126 (40.4%) were non-OSA non-BIC, 125 (40.1%) OSA non-BIC, 34 (10.9%) BIC non-OSA, and 27 (8.7%) comorbid insomnia and OSA. OSA and non-OSA children had a similar prevalence of BIC. Children in the comorbid insomnia and OSA group were significantly younger (2.22 ± 1.21 years). Younger age at polysomnography, premature birth, and increased periodic leg movements on polysomnography were independently associated with OSA in a multivariable analysis. Lower body mass index, regardless of OSA, was associated with BIC.

CONCLUSIONS

Current findings do not support an association between behavioral insomnia of childhood and obstructive sleep apnea in children. Healthcare providers should consider each of these sleep disorders in children presenting with sleep difficulties since each has distinct diagnostic and therapeutic options.

CITATION

Yelov L, Reiter J, Meira E Cruz M, Gileles-Hillel A. The association of obstructive sleep apnea and behavioral insomnia in children ages 10 and under. J Clin Sleep Med. 2024;20(2):245-251.

Generalised linear model of periodic limb movements

During sleep, the lower extremities exhibit periodic repetitive movements which are referred to as Period Limb Movement (PLM). Polysomnography (PSG) is the gold standard for diagnosing periodic limb movement disorder. The frequency of PLM episodes per hour of sleep (PLMI) determines the severity of the condition. PLM are generated by a dynamic process, however PLMI measures only the average PLM rate and does not capture the dynamic properties of PLM. Here, we characterise PLM dynamics using a generalised dynamic model as a function of sleep stage, timing of past PLM events and adjacent sleep disordered-breathing events. We analysed PSG recordings of 237 men and 222 women enrolled in the Multi-ethnic Study of Atherosclerosis (MESA) dataset to model dynamic PLM features. We statistically analysed whether these dynamics are associated with sex, age, and BMI. Modelling suggests instantaneous PLM rates are greater in men than women and higher in N1 and N2 non-rapid eye movement sleep than N3 and rapid eye movement sleep. The generalised model constitutes statistically robust approach towards the characterisation of periodic limb movement.Clinical Relevance- The generalised model may enable differentiated diagnostics of periodic limb movement disorder.

More than sleepiness: prevalence and relevance of nonclassical symptoms of obstructive sleep apnea

PURPOSE OF REVIEW

The purpose of this review is to describe the nonclassical symptoms and manifestations occurring in patients with obstructive sleep apnea (OSA), both from a standpoint of prevalence and in terms of clinical relevance. Particular emphasis will be given to nightmares, comorbid insomnia, restless legs syndrome and periodic limb movement disorder, bruxism, morning headache, nocturia, acid reflux, chronic cough and dysphagia.

RECENT FINDINGS

A review of the recent literature suggests that nonclassical symptoms have a high prevalence, are underestimated, and can interact with quality of life. Although these disturbances may occur together by mere coincidence, they may interact reciprocally. However, the degree of symptoms is not always correlated with OSA severity.

SUMMARY

OSA is a heterogeneous disease with variable clinical manifestations. This review highlights the need for detailed evaluation of patients with OSA to diagnose other important sleep disorders and clinical manifestations, given their frequent association.

Periodic limb movement index and severity of obstructive sleep apnea

Background

Periodic limb movements during sleep (PLMS) and obstructive sleep apnea syndrome (OSAS) are two frequent coincident sleep disorders. The association of PLMS with OSAS severity and predictors of PLMS in OSAS patients were investigated.

Material and method

This is a retrospective study that enrolled adult patients ≥ 16 years old who visited the sleep unit at Mouwasat Hospital, Saudi Arabia, between January 2021 and October 2021. All were subjected to full medical history, clinical examination, Epworth Sleepiness (ESS), STOP-Bang questionnaires, and standard overnight polysomnography. Subjects were subdivided into two groups based on PSG findings: group I, OSA patients (153). Patients were classified into mild n = 57 (AHI ≥ 5 and < 15), moderate n = 35 (AHI ≥ 15 and < 30), and severe n = 61 (AHI ≥ 30). Group II, control group included 100 subjects.

Result

There was a higher frequency of PLMS in OSA patients vs control group (with a statistically significant value). The study showed a statistically significantly positive correlation between PLMI and each of AHI, hypopnea index, desaturation index, and PLMs with arousal index, in contrast; it had a statistically significantly negative correlation with BMI among the OSA group. By performing multivariate logistic regression to predict the possible factors associated with the existence of PLMS among the OSA group, it was showed that the apnea index and desaturation index were statistically significant predictors.

Conclusion

The present study showed that OSA patients with PLM were older; had greater AHI, hypopnea index, desaturation index, and PLMs with arousal index; and had lower BMI. Further studies are needed for better understanding this complex relationship.