Race/ethnic differences in obstructive sleep apnea risk in patients with acute ischemic strokes in south Florida.

PURPOSE: Obstructive sleep apnea (OSA) is a risk factor for ischemic stroke, but it may differ between race/ethnic groups. The goal of our study was to examine the pre-stroke risk of OSA between three race/ethnic groups admitted for acute ischemic stroke in a tertiary urban hospital in South Florida. METHODS: Our sample was composed of patients with acute ischemic strokes evaluated at a teaching hospital over a 3-year period. Race/ethnicity was defined by self-identification, modeled after the US census and categorized into non-Hispanic whites, non-Hispanic blacks, and Hispanics. Pre-stroke risk of OSA was assessed with the Berlin questionnaire and categorized into high- or low-risk categories. We performed binary logistic regression to evaluate the pre-stroke risk of OSA in Hispanics and non-Hispanic blacks with non-Hispanic whites as the reference, adjusting for age, body mass index, hypertension, diabetes, and smoking. RESULTS: There were 176 patients with acute ischemic strokes of which 44 % were Hispanics, 44 % non-Hispanic Blacks, and 12 % non-Hispanic whites. A higher frequency of patients at high risk for OSA was seen in 60 % of Hispanics, 54 % of non-Hispanic blacks, and 33 % of non-Hispanic whites. Hispanics (OR, 2.6; 95 % CI 1.1-6.4) had a higher frequency of patients at high risk for OSA compared to non-Hispanic whites, adjusting for covariates. There were no differences between non-Hispanic blacks (OR, 1.2; 0.5-2.9 and non-Hispanic whites. DISCUSSION: We observed higher frequency of patients at high risk for OSA in Hispanics with acute ischemic strokes in South Florida.

Covert Tracking to Immersive Stimuli in Traumatic Brain Injury Subjects With Disorders of Consciousness.

Eye tracking assessments are clinician dependent and can contribute to misclassification of coma. We investigated responsiveness to videos with and without audio in traumatic brain injury (TBI) subjects using video eye-tracking (VET). We recruited 20 healthy volunteers and 10 unresponsive TBI subjects. Clinicians were surveyed whether the subject was tracking on their bedside assessment. The Coma Recovery Scale-Revised (CRS-R) was also performed. Eye movements in response to three different 30-second videos with and without sound were recorded using VET. The videos consisted of moving characters (a dancer, a person skateboarding, and Spiderman). Tracking on VET was defined as visual fixation on the character and gaze movement in the same direction of the character on two separate occasions. Subjects were classified as "covert tracking" (tracking using VET only), "overt tracking" (VET and clinical exam by clinicians), and "no tracking". A k-nearest-neighbors model was also used to identify tracking computationally. Thalamocortical connectivity and structural integrity were evaluated with EEG and MRI. The ability to obey commands was evaluated at 6- and 12-month follow-up. The average age was 29 (± 17) years old. Three subjects demonstrated "covert tracking" (CRS-R of 6, 8, 7), two "overt tracking" (CRS-R 22, 11), and five subjects "no tracking" (CRS-R 8, 6, 5, 6, 7). Among the 84 tested trials in all subjects, 11 trials (13%) met the criteria for "covert tracking". Using the k-nearest approach, 14 trials (17%) were classified as "covert tracking". Subjects with "tracking" had higher thalamocortical connectivity, and had fewer structures injured in the eye-tracking network than those without tracking. At follow-up, 2 out of 3 "covert" and all "overt" subjects recovered consciousness versus only 2 subjects in the "no tracking" group. Immersive stimuli may serve as important objective tools to differentiate subtle tracking using VET.

Covert Tracking to Visual Stimuli in Comatose Patients With Traumatic Brain Injury.

OBJECTIVES: This study investigated video eye tracking (VET) in comatose patients with traumatic brain injury (TBI). METHODS: We recruited healthy participants and unresponsive patients with TBI. We surveyed the patients' clinicians on whether the patient was tracking and performed the Coma Recovery Scale-Revised (CRS-R). We recorded eye movements in response to motion of a finger, a face, a mirror, and an optokinetic stimulus using VET glasses. Patients were classified as covert tracking (tracking on VET alone) and overt tracking (VET and clinical examination). The ability to obey commands was evaluated at 6-month follow-up. RESULTS: We recruited 20 healthy participants and 10 patients with TBI. The use of VET was feasible in all participants and patients. Two patients demonstrated covert tracking (CRS-R of 6 and 8), 2 demonstrated overt tracking (CRS-R of 22 and 11), and 6 patients had no tracking (CRS-R of 8, 6, 5, 7, 6, and 7). Five of 56 (9%) tracking assessments were missed on clinical examination. All patients with tracking recovered consciousness at follow-up, whereas only 2 of 6 patients without tracking recovered at follow-up. DISCUSSION: VET is a feasible method to measure covert tracking. Future studies are needed to confirm the prognostic value of covert tracking.

Sleep and stroke.

Obstructive Sleep-Disordered Breathing (OSDB) is an under-recognized risk factor for stroke. OSDB is associated with traditional vascular risk factors such as hypertension, obesity, and diabetes, and can influence the risk for stroke through direct and indirect mechanisms. Untreated OSDB may also influence rehabilitation efforts and functional outcome following a stroke, as well as the risk for stroke recurrence. Stroke risk is greatly reduced if the OSDB is adequately treated. Conversely, OSDB may be exacerbated or caused by stroke. Increasing awareness and improving screening for OSDB is paramount in the primary and secondary prevention of stroke, and in improving stroke outcomes. The following review article is intended to highlight the current basics of epidemiology, clinical characteristics, pathophysiology, diagnosis, and treatment of OSDB in relation to stroke.

Role of Obstructive Sleep Apnea in Cognitive Impairment.

Obstructive sleep apnea (OSA) is a prevalent sleep related breathing disorder characterized by repetitive collapse of the upper airways leading to intermittent hypoxia and sleep disruption. Clinically relevant neurocognitive, metabolic and cardiovascular disease often occurs in OSA. Systemic hypertension, coronary artery disease, type 2 diabetes mellitus, cerebral vascular infarctions and atrial fibrillation are among the most often cited conditions with causal connections to OSA. Emerging science suggest that untreated and undertreated OSA increases the risk of developing cognitive impairment, including vascular dementia and neurodegenerative disorders, like Alzheimer's disease. As with OSA, cardiovascular disease and type 2 diabetes mellitus, the incidence of dementia increases with age. Given our rapidly aging population, dementia prevalence will significantly increase. The aim of this treatise is to review current literature linking OSA to dementia and explore putative mechanisms by which OSA might facilitate the development and progression of dementia.

Obstructive Sleep Apnea Phenotypes and Markers of Vascular Disease: A Review.

Obstructive sleep apnea (OSA) is a chronic and heterogeneous disorder that leads to early mortality, stroke, and cardiovascular disease (CVD). OSA is defined by the apnea-hypopnea index, which is an index of OSA severity that combines apneas (pauses in breathing) and hypopneas (partial obstructions in breathing) associated with hypoxemia. Yet, other sleep metrics (i.e., oxygen nadir, arousal frequency), along with clinical symptoms and molecular markers could be better predictors of stroke and CVD outcomes in OSA. The recent focus on personalized medical care introduces the possibility of a unique approach to the treatment of OSA based on its phenotypes, defined by pathophysiological mechanisms and/or clinical presentation. We summarized what is known about OSA and its phenotypes, and review the literature on factors or intermediate markers that could increase stroke risk and CVD in patients with OSA. The OSA phenotypes where divided across three different domains (1) clinical symptoms (i.e., daytime sleepiness), (2) genetic/molecular markers, and (3) experimental data-driven approach (e.g., cluster analysis). Finally, we further highlight gaps in the literature framing a research agenda.

Obstructive sleep apnea and stroke: links to health disparities.

Obstructive sleep apnea (OSA) is a novel cardiovascular and cerebrovascular risk factor that presents unique opportunities to understand and reduce seemingly intractable stroke disparity among non-Hispanic blacks and Hispanic/Latinos. Individuals from these 2 groups have up to a 2-fold risk of stroke and greater burden of OSA. Obstructive sleep apnea directly and indirectly increases risk of stroke through a variety of autonomic, chemical, and inflammatory mechanisms and vascular risk factors such as hypertension, obesity, and diabetes mellitus. Untreated OSA exacerbates poststroke prognosis, as it may also influence rehabilitation efforts and functional outcomes such as cognitive function after a stroke. Conversely, treatment of OSA may reduce the risk of stroke and may yield better poststroke prognosis. Unfortunately, in racial/ethnic minority groups, there are limited awareness, knowledge, and screening opportunities for OSA. Increasing awareness and improving screening strategies for OSA in minorities may alleviate stroke risk burden and improve stroke outcomes in these populations. This review article is intended to highlight the epidemiology, clinical characteristics, pathophysiology, diagnosis, and treatment of OSA in relation to stroke risk, with an emphasis on race-ethnic disparities.

Vascular Dementia.

The purpose of this review is to highlight existing literature on the epidemiology, pathophysiology, and novel risk factors for vascular dementia. We further examine the evidence linking chronic brain hypoperfusion induced by a variety of cardiovascular diseases to the development of vascular dementia. In the elderly, in whom cerebral perfusion is diminished by the aging process, additional reduction in cerebral blood flow stemming from exposure to potentially modifiable vascular risk factors increases the probability of developing vascular dementia. Finally, we discuss the association between obstructive sleep apnea, an underrecognized risk factor for stroke, and vascular dementia. Obstructive sleep apnea is linked to cerebrovascular disease through many intermediary vascular risk factors and may directly cause cerebrovascular damage through microvacular disease. Insight into how cardiovascular risk factors induce vascular dementia offers an enhanced understanding of the multifactorial pathophysiology by this disorder and ways of preventing and managing the cerebrovascular precursors of vascular dementia. Many vital questions about the relation of obstructive sleep apnea with stroke and vascular dementia are still unanswered and await future well-designed studies.

Sleep disordered breathing, insomnia symptoms, and sleep quality in a clinical cohort of U.S. Hispanics in south Florida.

STUDY OBJECTIVES: There is a paucity of information on the epidemiology of sleep disorders among US Hispanics. This study describes the frequency of sleep disordered breathing (SDB) risk, insomnia complaints, poor sleep quality, and daytime somnolence in a clinical cohort of ethnically diverse US Hispanics living in South Florida. METHODS: We explored the presence of sleep disorders in a cohort of Hispanics seen at primary care, pulmonary, and sleep clinics at the University of Miami and Miami Veterans Affair Medical Center. Participants completed validated questionnaires, evaluating risk of SDB, presence of insomnia symptoms, sleep quality, and daytime sleepiness. Polysomnography was completed on the majority of the sleep clinic participants. RESULTS: Participants (N = 282; 62% male; mean age 54 ± 15 years; mean BMI 31 ± 6 kg/m(2)) included Hispanics of Cuban, Puerto Rican, Central/South American, and Caribbean heritage. Excessive daytime sleepiness was noted by 45% of participants. Poor sleep quality was reported by 49%; 76% screened high risk for SDB, and 68% had insomnia symptoms. Sleep disorders were more commonly reported in sleep clinic participants; however, 54% of non-sleep clinic participants were high risk for SDB, 35% had insomnia complaints, 28% had poor sleep quality, and 18% reported daytime sleepiness. CONCLUSIONS: Sleep disorders (including SDB) are common in clinical samples of Hispanics in South Florida. These findings highlight the urgent need for linguistically relevant and culturally responsive screening, awareness and education programs in clinical sleep medicine among US Hispanics. CITATION: Shafazand S; Wallace DM; Vargas SS; Del Toro Y; Dib S; Abreu AR; Ramos A; Nolan B; Baldwin CM; Fleming L. Sleep disordered breathing, insomnia symptoms, and sleep quality in a clinical cohort of US Hispanics in South Florida. J Clin Sleep Med 2012;8(5):507-514.

Snoring and insomnia are not associated with subclinical atherosclerosis in the Northern Manhattan Study.

BACKGROUND: Sleep-disordered breathing is a risk factor for stroke, but its association with subclinical atherosclerosis remains controversial. Snoring and insomnia are frequently comorbid with sleep-disordered breathing and may contribute to stroke. Data on the relationship between snoring and insomnia with atherosclerotic disease are sparse. We investigated the relationship between markers of subclinical atherosclerosis, insomnia, snoring, and carotid intima-media thickness, in the Northern Manhattan Study. METHODS: A group of 1605 participants (mean age 65 +/- 8 years; 40% men; 61% Hispanic, 19% black, 20% white) who had carotid intima-media thickness measurements performed was assessed for self-reported sleep habits. Habitual snoring was defined as self-reported snoring greater than four times per week. Presence of insomnia was based on three items extracted from the Hamilton Rating Scale for Depression. Carotid intima-media thickness was expressed as a mean composite measure of intima-media thickness in the carotid bifurcation, common, and internal carotid artery. Multivariate linear regression models were used to identify associations between snoring, insomnia, and carotid intima-media thickness. RESULTS: Habitual snoring was present in 29% of the subjects and insomnia in 26%. There was a higher prevalence of self-reported snoring (84%) and insomnia (66%) among Hispanics than non-Hispanics. The mean total carotid intima-media thickness was 0.95 +/- 0.09 mm; among those with self-reported snoring was 0.94 +/- 0.09 mm; and among those with insomnia was 0.95 +/- 0.08 mm. After controlling for age, gender, race-ethnicity, body mass index and cardiovascular risk factors, snoring (P=0.986) and insomnia (P=0.829) were not significantly associated with increased carotid intima-media thickness. CONCLUSION: Snoring and insomnia were not significantly associated with subclinical atherosclerosis in this population-based community cohort.