Sleep Apnea and Other Sleep-Wake Disorders in Stroke

Insomnia Burden and Future Perspectives

Insomnia is an important but widely ignored health problem in modern society. Despite unequivocal evidence on its large prevalence, health and social impacts, comorbidities, and various pharmacologic and nonpharmacologic (behavioral and device-based) approaches, its effective management is still difficult and often incomplete. This article discusses the role of insomnia in modern societies, newer complicating factors, and its overall social and public health burden. Acute insomnia and sleep difficulties during pandemic and confinement are reviewed. The article also focuses on newer developments accumulating in the field of insomnia and possible future trends.

Sleep-disordered breathing and stroke: chicken or egg?

The bidirectional interaction between sleep-disordered breathing (SDB) and stroke has been the subject of many studies. On the one hand, different forms of SDB, and especially obstructive sleep apnea, increase the risk of stroke either directly or indirectly by influencing other known cardiovascular risk factors such as arterial hypertension and arrhythmias. On the other hand, stroke itself can cause either de novo appearance of SDB, aggravate a pre-existing SDB, or trigger a transition from one type of pathological SDB pattern into another. In this review, we discuss some aspects of this "chicken or egg" relationship.

Application of Transcranial Direct Current Stimulation in Neurorehabilitation: The Modulatory Effect of Sleep

The relationship between sleep disorders and neurological disorders is often reciprocal, such that sleep disorders are worsened by neurological symptoms and that neurological disorders are aggravated by poor sleep. Animal and human studies further suggest that sleep disruption not only worsens single neurological symptoms but may also lead to long-term negative outcomes. This suggests that sleep may play a fundamental role in neurorehabilitation and recovery. We further propose that sleep may not only alter the efficacy of behavioral treatments but also plasticity-enhancing adjunctive neurostimulation methods, such as transcranial direct current stimulation (tDCS). At present, sleep receives little attention in the fields of neurorehabilitation and neurostimulation. In this review, we draw together the strands of evidence from both fields of research to highlight the proposition that sleep is an important parameter to consider in the application of tDCS as a primary or adjunct rehabilitation intervention.

Clinical outcome after acute ischaemic stroke: the influence of restless legs syndrome

BACKGROUND AND PURPOSE

the objective was to evaluate the presence of Restless Legs Syndrome (RLS) in acute stroke, its association with sleep disturbances and clinical outcome during long-term follow-up.

METHODS

this was a longitudinal study (N = 96, 59 men, mean age 64.0 ± 8.9) of cases with acute ischaemic stroke. Patients were asked about the occurrence of RLS symptoms before the cerebrovascular event. RLS was diagnosed using the criteria established by the International RLS Study Group. Stroke outcome was estimated by the Barthel Index and the modified Rankin Scale. Daytime somnolence (Epworth Sleepiness Scale -ESS > 10), poor sleep quality (Pittsburgh Sleep Quality Index -PSQI > 5) and risk of obstructive sleep apnea (OSA) (Berlin questionnaire) were evaluated.

RESULTS

twelve patients (12.5%) met the diagnostic criteria for RLS. All cases had symptoms of RLS before stroke. However, none of the cases had a previous medical diagnosis of RLS or were on use of specific medication. In only one case, a family history of RLS was found. In all patients, RLS symptoms started after the age of 40 (mean age 64 ± 6.7). Daytime sleepiness (44.8%) and poor quality sleep (62.8%) were present. Patients with RLS (12.5%) presented greater neck circumference (P = 0.04) and worse sleep quality (P = 0.007). Risk of OSA (56.2%) was associated with hypertension [OR = 0.12; CI=0.03-0.42]. Stroke outcome was significantly worse at three and 12 months (ancova, P < 0.005) in patients with RLS, remaining after adjustment for diabetes and body mass index (P < 0.05).

CONCLUSIONS

patients with acute stroke and RLS have worse clinical outcome, at three and 12 months of follow-up.

Central periodic breathing during sleep in acute ischemic stroke

BACKGROUND AND PURPOSE

It has been suggested that central periodic breathing during sleep (CPBS) may develop in unilateral supratentorial stroke without cardiopulmonary disease and disturbed consciousness. Not many data existed about such patients.

METHODS

Of 31 patients with first-ever stroke, we report 3 patients with CPBS in the absence of cardiopulmonary and vigilance disturbances. Patient assessments included polysomnography, MRI and echocardiography. Nocturnal breathing was reassessed after 1 to 3 months.

RESULTS

The patients had ischemic strokes in the left cingulate cortex, left insula and right paramedian thalamus. They were fully conscious when submitted to sleep recordings and lacked overt cardiovascular dysfunctions (ejection fractions=67%, 48%, 65%). CPBS was present during 18% to 24% of sleep. In all patients, breathing improved during stroke recovery.

CONCLUSIONS

CPBS may be present in strokes involving autonomic (insula) and volitional (cingulate cortex, thalamus) respiratory networks. As such, CPBS partly resolves within weeks.

Prevalence and predictors of pain and fatigue after stroke: a population-based study

Pain and fatigue are two often overlooked symptoms after stroke. Their prevalence and determinants are not well understood. In this study patients with first-ever stroke (n=377) were examined at baseline and after 1 year. General characteristics of the patients, as well as stroke type, stroke severity and risk factors were registered at baseline. After 1 year survivors (n=253) were examined with respect to residual impairment, disability, cognition and depression. They were asked whether they had experienced pain and/or fatigue which had started after the stroke, and which the patient felt to be stroke related. Twenty-eight patients (11%) had stroke-associated pain and 135 (53%) had stroke-associated fatigue. Pain was associated with depression and different manifestations of stroke severity, especially degree of paresis at baseline. Fatigue was more associated with physical disability. In univariate analysis, fatigue was also associated with sleep disturbances. In conclusion, it is important to be aware of the occurrence of pain and fatigue after stroke, because these symptoms are common, they impair quality of life and they are potentially treatable. Post-stroke depression may coexist with pain and fatigue. The detection of one symptom should lead to consideration of the others. Follow-up and individual assessment of stroke patients is crucial.

Causes of Cheyne-Stokes respiration

Cheyne-Stokes respiration (CSR) is one of several types of unusual breathing with recurrent apneas (dysrhythmias). Reported initially in patients with heart failure or stroke, it was then recognized both in other diseases and as a component of the sleep apnea syndrome. CSR is potentiated and perpetuated by changing states of arousal that occur during sleep. The recurrent hypoxia and surges of sympathetic activity that often occur during the apneas may have serious health consequences. Heart failure and stroke are risk factors for sleep apnea. The recurrent apneas and intermittent hypoxia occurring with sleep apnea further damage the heart and brain. Although all breathing dysrhythmias do not have the same cause, instability in the feedback control involved in the chemical regulation of breathing is the leading cause of CSR. Mathematical models have helped greatly in the understanding of the causes of recurrent apneas.