Sleep and comorbid neurologic disorders

Risk of dementia in patients with primary insomnia: a nationwide population-based case-control study

BACKGROUND

To investigate the association between primary insomnia and dementia using a Taiwanese population-based database.

METHODS

This case-control study involved a subset of Taiwan's National Health Insurance Research Database of reimbursement claims. We included 51,734 patients who were diagnosed with primary insomnia from 2002 to 2004 as the test group and 258,715 nonprimary insomnia participants aged 20 years or older as the reference group. We excluded patients under 20 and those with depression, post-traumatic stress disorder, and/or sleep disorders caused by organic lesion(s), drugs, or alcohol. We used a Cox proportional hazards model to assess the primary insomnia on the risk of developing dementia after adjusting for sociodemographic characteristics and comorbidities.

RESULTS

The primary insomnia cohort had a higher prevalence of diabetes, dyslipidemia, hypertension, coronary heart disease, chronic liver disease, and chronic kidney disease at baseline. After adjusting for select comorbidities, primary insomnia remained a significant predisposing factor for developing dementia, and was associated with a 2.14-fold (95% confidence interval, 2.01-2.29) increase in dementia risk. We also found a higher risk of dementia in younger patients.

CONCLUSIONS

Taiwanese patients with primary insomnia, especially those under 40, had a higher risk of developing dementia than those without primary insomnia.

Brain Atrophy of Secondary REM-Sleep Behavior Disorder in Neurodegenerative Disease

BACKGROUND

Rapid eye movement sleep behavior disorder (RBD) may present as an early manifestation of an evolving neurodegenerative disorder with alpha-synucleinopathy.

OBJECTIVE

We investigated that dementia with RBD might show distinctive cortical atrophic patterns.

METHODS

A total of 31 patients with idiopathic Parkinson's disease (IPD), 23 with clinically probable Alzheimer's disease (AD), and 36 healthy controls participated in this study. Patients with AD and IPD were divided into two groups according to results of polysomnography and rated with a validated Korean version of the RBD screening questionnaire (RBDSQ-K), which covers the clinical features of RBD. Voxel-based morphometry was adapted for detection of regional brain atrophy among groups of subjects.

RESULTS

Scores on RBDSQ-K were higher in the IPD group (3.54 ± 2.8) than in any other group (AD, 2.94 ± 2.4; healthy controls, 2.31 ± 1.9). Atrophic changes according to RBDSQ-K scores were characteristically in the posterior part of the brain and brain stem, including the hypothalamus and posterior temporal region including the hippocampus and bilateral occipital lobe. AD patients with RBD showed more specialized atrophic patterns distributed in the posterior and inferior parts of the brain including the bilateral temporal and occipital cortices compared to groups without RBD. The IPD group with RBD showed right temporal cortical atrophic changes.

CONCLUSION

The group of patients with neurodegenerative diseases and RBD showed distinctive brain atrophy patterns, especially in the posterior and inferior cortices. These results suggest that patients diagnosed with clinically probable AD or IPD might have mixed pathologies including α-synucleinopathy.

Study of sleep microstructure in patients of migraine without aura

PURPOSE

Although the relationship between sleep and migraine has been widely reported, studies on sleep microstructure are few. The aim was to study and compare microstructural polysomnographic characteristics in patients of "migraine without aura" (MOA) with controls.

METHODS

Twenty-five patients of MOA and 25 age- and gender-matched healthy controls were subjected to overnight polysomnography. Microstructural sleep analysis, including arousal and cyclic alternating pattern (CAP) analysis was performed. Arousals and CAP parameters were compared between the two groups using the Mann-Whitney U test (p ≤ 0.05).

RESULTS

The overall arousal index (p = 0.528) and that during non-rapid eye movement (NREM) sleep (p = 0.503) were comparable between the two groups. However, the arousal index was lower in migraineurs during rapid eye movement (REM) sleep (p = 0.001). The overall CAP rate (p = 0.020) as well as the number of CAP cycles and sequences (p = 0.032) was lower among migraineurs. The total phase A duration (p < 0.0001) was increased, and conversely, phase B duration (p = 0.001) was decreased in migraineurs. The phase A1 duration (p = 0.036) was higher in migraineurs. Finally, phase A1 (p = 0.357) index was comparable, and conversely, A2 (p < 0.0001) and A3 (p = 0.020) indices were decreased in migraineurs.

CONCLUSIONS

This study showed a decreased REM arousability as well as a decreased overall CAP rate and CAP cycling in patients with migraine as compared to controls. This indicates that there is probably an alteration of the arousal mechanisms in patients with migraine that may facilitate the occurrence of headache paroxysms during sleep.

Association between sleep quality and cardiovascular health: a door-to-door survey in rural Ecuador

OBJECTIVES

Cardiovascular correlates of sleep disorders have not been well investigated in underserved populations. The aim of this door-to-door survey was to evaluate the association between sleep quality and cardiovascular health status in persons aged ≥40 years living in a village that is representative of rural Ecuador.

METHODS

All stroke-free Atahualpa residents aged ≥40 years were screened with a validated Spanish version of the Pittsburgh Sleep Quality Index and the seven cardiovascular health (CVH) metrics proposed by the American Heart Association to assess the CVH status.

RESULTS

A total of 635 persons (mean age 59 ± 13 years; 58 % women) were identified. A poor sleep quality was present in 27 % of the subjects (95 % CI 24-31 %) and a poor cardiovascular health in 69 % (95 % CI 63-71 %). In a multivariate logistic regression model, a poor sleep quality was associated with some CVH metrics in the poor range, including smoking status (p = 0.026), physical activity (p = 0.01) and blood glucose levels (p = 0.036).

CONCLUSIONS

A poor sleep quality may be linked to individual cardiovascular risk factors in this underserved Latin American population. This finding provides useful insights for the implementation of regional prevention priorities.

Prevalence and predictors of headache in patients referred to polysomnography

Background

The objectives of this study were; (1) to assess the prevalence and frequency of headache in patients referred to polysomnography (PSG) due to a clinical suspicion of obstructive sleep apnea (OSA) or another sleep disturbance and compare with a reference population, and (2) to assess the association of OSA severity with headache and headache frequency.

Methods

A total of 784 participants filled in a headache questionnaire between 2003 and 2009 at the Department of Clinical Neurophysiology, Akershus University Hospital. Of these patients 477 were suspected to have OSA, and 307 had other sleep complaints. We assessed the prevalence of headache and monthly headache frequencies, as well as sleep apnea severity using an apnea-hypopnea index (AHI). The association of headache and monthly headache frequencies with PSG subgroups was assessed using multivariate logistic and ordered logistic regression analysis.

Results

The frequency of headache was not associated with the severity of OSA. Patients referred to a sleep study for any reason had higher odds ratio (OR) for having experienced headache during the past year than population controls after adjustment for age, gender and education, i.e. patients with normal AHI had OR of 3.56, patients with OSA had OR of 3.51, and patients with other sleep disturbances had OR of 3.33. Similarly, the adjusted OR of being in a higher category of monthly headache frequency compared to controls was higher in those with normal AHI (OR 3.42), OSA (OR 3.29), and other sleep disturbances (OR 3.00).

Conclusions

The odds of headache and headache frequency were higher in subjects referred to a PSG for any sleep disturbance independently of OSA, compared to general population controls. However, there was no association between experiencing headache during the past year or headache frequency with OSA severity.