Does Obstructive Sleep Apnea Increase Cognitive Deficits in Pediatric Sickle Cell Disease?

OBJECTIVES: Although pediatric obstructive sleep apnea (OSA) is estimated to affect 2-3% of the general population, its prevalence in sickle cell disease (SCD) is much higher, with research suggesting a prevalence rate of upwards of 40%. Despite the similar underlying pathophysiological mechanisms of neurocognitive effects in pediatric OSA and SCD, there is a scarcity of information on how these two conditions interact. The aim of this study was to better understand the contribution of sleep apnea to neurocognitive deficits in children diagnosed with SCD. METHOD: This study assessed cognitive function in 26 children with comorbid SCD and OSA, 39 matched comparisons with SCD only, and 59 matched comparisons in children without a chronic health condition. RESULTS: There were significant differences on measures of processing speed and reading decoding, with children without a chronic health condition scoring better than both chronic health condition groups. Additionally, the no chronic health condition group performed better on a test of quantitative knowledge and reasoning and a test of visual-spatial construction than the SCD-only group. Contrary to our hypotheses, there were no between-group differences suggesting an additive impact of OSA on cognition. Exploratory analyses revealed associations within the group that had OSA showing that more severe OSA correlated with lower performance on measures of processing speed and quantitative knowledge/reasoning. CONCLUSIONS: Children with comorbid OSA and SCD do not present with greater deficits in cognitive functioning than children with SCD alone. However, severe OSA may confer additional risk for neurocognitive impairments.

Comorbid obstructive sleep apnea and increased risk for sickle cell disease morbidity.

PURPOSE: Sickle cell disease (SCD) imparts an increased risk for obstructive sleep apnea (OSA) in childhood. Studies of pediatric SCD have identified an increased risk for pain and neurologic complications with comorbid OSA. We determined the rate of a broad range of SCD-related medical complications to better characterize the spectrum of SCD complications related to OSA. METHODS: Retrospective chart review at a single hematology clinic identified 641 youth with SCD who received consistent screenings for OSA as part of routine hematological health maintenance visits over an 11-year period. Medical complication rates in the 136 children with OSA determined by polysomnography exams were compared to 136 matched controls at lower risk for OSA due to negative OSA screenings or exams. RESULTS: Children with SCD and OSA had higher overall rates of SCD complications than low OSA-risk controls; lung morbidity showed the largest effect size. Infection, cardiovascular, and neurologic complications occurred at higher rates in children with OSA. Children with comorbid OSA had higher rates of SCD complications both before and after OSA diagnosis. CONCLUSIONS: OSA in children with SCD is associated with higher rates of a broad range of SCD complications, including pneumonia and acute chest syndrome. Routine screenings, diagnosis, and increased therapeutic intervention for children with comorbid OSA could decrease SCD morbidity.

Overlapping biological mechanisms underlying sickle cell disease, stress, and depression: a stress-vulnerability framework.

LEARNING OBJECTIVES: After participating in this activity, learners should be better able to:1. Evaluate the overlap between sickle cell disease (SCD) and depression.2. Identify sources of psychological stress and biological vulnerabilities toward developing depression in patients with SCD.3. Assess the potential mechanisms underlying SCD, stress, and depression.Depression is a common co-occurring disorder in persons with sickle-cell disease (SCD). Individuals with this chronic illness may be particularly vulnerable to depression. In addition to risk factors for depression specifically related to SCD, these individuals typically experience further psychological stress due to multiple risk factors in their environment. To date, however, little research has focused on the co-occurring biological mechanisms across these conditions and how those mechanisms may interact to produce depressive symptoms. In this review we use a stress-vulnerability framework to describe the sources of psychological stress and the SCD factors that increase the risk of depression. We suggest that several biological factors, such as nitric oxide and cytokines, may play an important role in co-occurring stress, SCD, and depression. The interaction of these factors may be of particular importance for understanding the comorbidity of SCD and depression. Implications for current treatment and future research are discussed.

EXAMINER executive function battery and neurologic morbidity in pediatric sickle cell disease.

Sickle cell disease (SCD) is blood disorder with a high risk for cerebral vascular morbidities that impact neurocognitive functioning. Specific cognitive abilities are known to be more sensitive to neurologic effects of SCD than IQ scores, yet there is little consensus about which measures to use to assess neurocognitive functioning. We evaluated the ability of the Executive Abilities: Methods and Instruments for Neurobehavioral Evaluation and Research (EXAMINER) Battery to detect neurologic effects in SCD. Thirty-two youth with SCD and sixty demographically-matched comparison youth completed the EXAMINER Battery and selected tests from the Woodcock-Johnson Tests of Cognitive Ability, 3rd edition (WJ-III). Neurologic severity was examined via clinical history for morbidities and midsagittal corpus callosum (CC) area. Results indicated cognitive performance decreased with increasing neurologic morbidity across all cognitive measures; two of four EXAMINER factors were related to CC area. The association with clinical history and midsagittal CC area appeared at least as large for the Examiner Battery scores as for the WJ-III measures. The Examiner Battery showed sensitivity to neurologic history and white matter effects in SCD; this new measure compares favorably to established measures of disease-related neurocognitive effects, but would benefit from further development.

Improved motor sequence retention by motionless listening.

This study examined the effect of listening to a newly learned musical piece on subsequent motor retention of the piece. Thirty-six non-musicians were trained to play an unfamiliar melody on a piano keyboard. Next, they were randomly assigned to participate in three follow-up listening sessions over 1 week. Subjects who, during their listening sessions, listened to the same initial piece showed significant improvements in motor memory and retention of the piece despite the absence of physical practice. These improvements included increased pitch accuracy, time accuracy, and dynamic intensity of key pressing. Similar improvements, though to a lesser degree, were observed in subjects who, during their listening sessions, were distracted by another task. Control subjects, who after learning the piece had listened to nonmusical sounds, showed impaired motoric retention of the piece at 1 week from the initial acquisition day. These results imply that motor sequences can be established in motor memory without direct access to motor-related information. In addition, the study revealed that the listening-induced improvements did not generalize to the learning of a new musical piece composed of the same notes as the initial piece learned, limiting the effects to musical motor sequences that are already part of the individual's motor repertoire.