Exploring the relationship of sleep, cognition, and cortisol in sickle cell disease

Background: Neurocognitive impairment is common in people with Sickle Cell Disease (SCD) and evidence is accumulating that sleep disturbances play a role. The interaction between cortisol and sleep in the general population is associated with cognition as well as general wellbeing but there are few data in SCD. We aimed to understand the relationship between cortisol and sleep in individuals with SCD and explored associations with cognition. Methods: Forty-five participants of black heritage (SCD: N = 27, 9–29 years, 16 females; Controls: N = 18, 11–25 years, 13 females) were recruited from the community between 2018 - 2020. Participants completed standardized questionnaires about their sleep behaviour and wore actigraphy MotionWatch8 for 7 nights to assess nocturnal sleep patterns. Salivary cortisol samples were taken on wakening and 3 times after 14:00. Cognition was assessed using the Wechsler Intelligence Scales for children and adults. Results: People with SCD took longer to fall asleep and experienced greater wake bouts, mobile minutes and fragmented sleep compared to controls. Although non-significant, people with SCD experienced lower morning cortisol, with a flattened diurnal cortisol ratio compared to controls. Interestingly, SCD participants, but not controls, with low diurnal variation scored lowest on processing speed (PSI) and perceptual reasoning index (PRI). A moderator analysis revealed that the effect of morning cortisol and diurnal cortisol ratio on PRI by group health (i.e., SCD and healthy controls) depended on sleep quality. Discussion: Sleep and cortisol may play a crucial role in the expression of cognitive difficulties seen in SCD. This should be considered for the development of interventions to optimise cognitive functioning and sleep. This, in turn, could positively impact on secretion of cortisol and general health in SCD

Effects of regional brain volumes on cognition in sickle cell anemia: A developmental perspective

BACKGROUND AND OBJECTIVES: Cognitive difficulties in people with sickle cell anemia (SCA) are related to lower processing speed index (PSI) and working memory index (WMI). However, risk factors are poorly understood so preventative strategies have not been explored. Brain volumes, specifically white matter volumes (WMV) which increases through early adulthood, have been associated with better cognition in healthy typically developing individuals. In patients with SCA, the reduced WMV and total subcortical volumes noted could explain cognitive deficits. We therefore examined developmental trajectories for regional brain volumes and cognitive endpoints in patients with SCA. METHODS: Data from two cohorts, the Sleep and Asthma Cohort and Prevention of Morbidity in SCA, were available. MRI data included T1-weighted axial images, pre-processed before regional volumes were extracted using Free-surfer. PSI and WMI from the Weschler scales of intelligence were used to test neurocognitive performance. Hemoglobin, oxygen saturation, hydroxyurea treatment and socioeconomic status from education deciles were available. RESULTS: One hundred and twenty nine patients (66 male) and 50 controls (21 male) aged 8-64 years were included. Brain volumes did not significantly differ between patients and controls. Compared with controls, PSI and WMI were significantly lower in patients with SCA, predicted by increasing age and male sex, with lower hemoglobin in the model for PSI but no effect of hydroxyurea treatment. In male patients with SCA only, WMV, age and socioeconomic status predicted PSI, while total subcortical volumes predicted WMI. Age positively and significantly predicted WMV in the whole group (patients + controls). There was a trend for age to negatively predict PSI in the whole group. For total subcortical volume and WMI, age predicted decrease only in the patient group. Developmental trajectory analysis revealed that PSI only was significantly delayed in patients at 8 years of age; the rate of development for the cognitive and brain volume data did not differ significantly from controls. DISCUSSION: Increasing age and male sex negatively impact cognition in SCA, with processing speed, also predicted by hemoglobin, delayed by mid childhood. Associations with brain volumes were seen in males with SCA. Brain endpoints, calibrated against large control datasets, should be considered for randomized treatment trials

Quantification of Silent Cerebral Infarction on High-Resolution FLAIR and Cognition in Sickle Cell Anemia

Research in sickle cell anemia (SCA) has used, with limited race-matched control data, binary categorization of patients according to the presence or absence of silent cerebral infarction (SCI). SCI have primarily been identified using low-resolution MRI, with radiological definitions varying in lesion length and the requirement for abnormality on both fluid attenuated inversion recovery (FLAIR) and T1-weighted images. We aimed to assess the effect of published SCI definitions on global, regional, and lobar lesion metrics and their value in predicting cognition. One hundred and six patients with SCA and 48 controls aged 8-30 years underwent 3T MRI with a high-resolution FLAIR sequence and Wechsler cognitive assessment. Prevalence, number, and volume of lesions were calculated using a semi-automated pipeline for SCI defined as: (1) Liberal: any length (L-SCI); (2) Traditional: >3 mm in greatest dimension (T-SCI); (3) Restrictive; >3 mm in greatest dimension with a corresponding T1-weighted hypo-intensity (R-SCI). Globally, as hypothesized, there were large effects of SCI definition on lesion metrics in patients and controls, with prevalence varying from 24-42% in patients, and 4-23% in controls. However, contrary to hypotheses, there was no effect of any global metric on cognition. Regionally, there was a consistent distribution of SCI in frontal and parietal deep and juxta-cortical regions across definitions and metrics in patients, but no consistent distribution in controls. Effects of regional SCI metrics on cognitive performance were of small magnitude; some were paradoxical. These findings expose the challenges associated with the widespread use of SCI presence as a biomarker of white-matter injury and cognitive dysfunction in cross-sectional high-resolution MRI studies in patients with SCA. The findings indicate that with high-resolution MRI: (1) radiological definitions have a large effect on resulting lesion groups, numbers, and volumes; (2) there is a non-negligible prevalence of lesions in young healthy controls; and (3) at the group-level, there is no cross-sectional association between global lesion metrics and general cognitive impairment irrespective of lesion definition and metric. With high-resolution multi-modal MRI, the dichotomy of presence or absence of SCI does not appear to be a sensitive biomarker for the detection of functionally significant pathology; the search for appropriate endpoints for clinical treatment trials should continue

Prevention of Morbidity in Sickle Cell Disease (POMS2a)-overnight auto-adjusting continuous positive airway pressure compared with nocturnal oxygen therapy: a randomised crossover pilot study examining patient preference and safety in adults and children.

DESIGN: This randomised crossover trial compared nocturnal auto-adjusting continuous positive airway pressure (APAP) and nocturnal oxygen therapy (NOT) in adults and children with sickle cell anaemia, with patient acceptability as the primary outcome. Secondary outcomes included pulmonary physiology (adults), safety, and daily pain during interventions and washout documented using tablet technology. METHODS: Inclusion criteria were age > 8 years and the ability to use an iPad to collect daily pain data. Trial participation was 4 weeks; week 1 involved baseline data collection and week 3 was a washout between interventions, which were administered for 7 days each during weeks 2 and 4 in a randomised order. Qualitative interviews were transcribed verbatim and analysed for content using a funnelling technique, starting generally and then gaining more detailed information on the experience of both interventions. Safety data included routine haematology and median pain days between each period. Missing pain day values were replaced using multiple imputation. RESULTS: Ten adults (three female, median age 30.2 years, range 18-51.5 years) and eleven children (five female, median age 12 years, range 8.7-16.9 years) enrolled. Nine adults and seven children completed interviews. Qualitative data revealed that the APAP machine was smaller, easier to handle, and less noisy. Of 16 participants, 10 preferred APAP (62.5%, 95% confidence interval (CI) 38.6-81.5%). Haemoglobin decreased from baseline on APAP and NOT (mean difference -3.2 g/L (95% CI -6.0 to -0.2 g/L) and -2.5 g/L (95% CI -4.6 to 0.3 g/L), respectively), but there was no significant difference between interventions (NOT versus APAP, 1.1 (-1.2 to 3.6)). Pulmonary function changed little. Compared with baseline, there were significant decreases in the median number of pain days (1.58 for APAP and 1.71 for NOT) but no significant difference comparing washout with baseline. After adjustment for carry-over and period effects, there was a non-significant median difference of 0.143 (95% CI -0.116 to 0.401) days additional pain with APAP compared with NOT. CONCLUSION: In view of the point estimate of patient preference for APAP, and no difference in haematology or pulmonary function or evidence that pain was worse during or in washout after APAP, it was decided to proceed with a Phase II trial of 6 months APAP versus standard care with further safety monitoring for bone marrow suppression and pain. TRIAL REGISTRATION: ISRCTN46078697 . Registered on 18 July 2014

Transcranial doppler screening in children with Sickle Cell Anemia is feasible in central India and reveals high risk of stroke

Introduction: India has been identified as having the second largest number of births with sickle cell anemia (SCA) in the world after Africa, with estimated 44,400 new-borns affected per year. SCD was previously reported to have a milder course in children from India, with less severe disease among aboriginal tribal populations than in non-tribal populations. Recent reports indicate the occurrence of severe manifestations of SCD in both tribal and non-tribal populations in India. Stroke is one of the serious complications of SCD, but there are no data on transcranial Doppler (TCD) screening for evaluating children with SCD in India who may be at high risk for strokes. The objective of this study was to assess the feasibility of using TCD to measure time averaged maximum of the mean velocities (TAMMV) in the intracranial arteries in children attending a tertiary centre in central India. Methods: STUDY DESIGN: A cross sectional study was conducted in consecutively recruited stable children of either sex with homozygous SCA proven by electrophoresis and high performance liquid chromatography in the age group of 1-26 years. Patients who were febrile, acutely ill, hypoxic or asleep were not included in the study as these conditions can falsely elevate the intracranial blood flow velocities. Patients with hemoglobinopathies other than HbSS or S/b0 Thalassemia and those with a history of congenital neurological illness were excluded. DETERMINATION OF TCD VELOCITY: TCD was performed in a tertiary care center in Nagpur using either an imaging machine (Lasiq s8) in the department of radiology or a portable non-imaging TCD (Compumedics); for both a probe of frequency 2Mhz was used. Maximum values for TAMMV in the Middle (MCA) and Anterior (ACA) cerebral arteries were measured in all; for the non-imaging TCD values for posterior cerebral artery (PCA) and basilar artery were also obtained. The results of the first scan performed on these individuals were included in this study. Using values similar to the STOP trial, TAMMV of each of these vessels were categorized as follows: Normal <= 170cm/s; Conditional - between 170 and 199 cm/s; Abnormal >= 200 cm/s; Low <50 cm/s and unobtainable. MEASUREMENT OF HAEMATOLOGICAL VALUES: Laboratory parameters such as Hemoglobin, white blood cell count (WBC), Mean corpuscular volume (MCV) and hemoglobin F (HbF) levels of the patients in the study were also included if the parameters were available on the day of TCD or within 90 days of TCD study. MEASUREMENT OF HEIGHT, WEIGHT AND BMI: The height and weight of each of the patients on the day of TCD or within a period of 60 days from the TCD were measured and the body mass index (BMI) was calculated. Results One hundred and twenty children and youth aged 1-26 (median 7) years, 67 male (56%), were recruited. Of the 120 patients, 106 (88.5%) belonged to the Scheduled Caste category, 3 (2.5%) to the Scheduled Tribe category and 11 (9.1%) to the Other Classes category. Three (2.5%) had had a clinical stroke and 8 (7%) had had seizures, one of whom also had a stroke. Twenty-seven (23%) children had TAMMV outside the normal range. Five had abnormal TAMMV in the MCA (n=4) and/or ACA (n=1), 8 had conditional TAMMV in the MCA (n=7) and/or ACA (n=1) while 14 patients had low (n=12) or unobtainable (n=2) TAMMV in the MCA. One child with stroke had low TAMMV and one had conditional TAMMV while the third had normal TAMMV. Of the 7 with isolated seizures, one had low TAMMV and one had conditional TAMMV while the remaining 5 were normal. BMI was 8.6-25.3 (median 14.1), height/weight was 3.4-10.3 (median 6.5), hemoglobin was 43-134 (median 81) g/L, oxygen saturation 87-100 (median 99)%, HbF was 1.9-60 (median 21) g/dL, MCV was 59.1-96.7 (median 83.2) fl, WBC was 2.3-35.9 (median 10.1)*109. Those with TAMMV outside the normal range were not different from those with normal TAMMV in terms of age, BMI, Height/weight, or recent hemoglobin, oxygen saturation, HbF, MCV, or WBC

Exploring the relationship of sleep, cognition, and cortisol in sickle cell disease.

BACKGROUND: Neurocognitive impairment is common in people with Sickle Cell Disease (SCD) and evidence is accumulating that sleep disturbances play a role. The interaction between cortisol and sleep in the general population is associated with cognition as well as general wellbeing but there are few data in SCD. We aimed to understand the relationship between cortisol and sleep in individuals with SCD and explored associations with cognition. METHODS: Forty-five participants of black heritage (SCD: N = 27, 9-29 years, 16 females; Controls: N = 18, 11-25 years, 13 females) were recruited from the community between 2018 - 2020. Participants completed standardized questionnaires about their sleep behaviour and wore actigraphy MotionWatch8 for 7 nights to assess nocturnal sleep patterns. Salivary cortisol samples were taken on wakening and 3 times after 14:00. Cognition was assessed using the Wechsler Intelligence Scales for children and adults. RESULTS: People with SCD took longer to fall asleep and experienced greater wake bouts, mobile minutes and fragmented sleep compared to controls. Although non-significant, people with SCD experienced lower morning cortisol, with a flattened diurnal cortisol ratio compared to controls. Interestingly, SCD participants, but not controls, with low diurnal variation scored lowest on processing speed (PSI) and perceptual reasoning index (PRI). A moderator analysis revealed that the effect of morning cortisol and diurnal cortisol ratio on PRI by group health (i.e., SCD and healthy controls) depended on sleep quality. DISCUSSION: Sleep and cortisol may play a crucial role in the expression of cognitive difficulties seen in SCD. This should be considered for the development of interventions to optimise cognitive functioning and sleep. This, in turn, could positively impact on secretion of cortisol and general health in SCD

Lung Clearance Index May Detect Early Peripheral Lung Disease in Sickle Cell Anemia

RATIONALE: Chronic lung injury is common in sickle cell anemia (SCA) and worsens outcomes. Sensitive lung function tests might predict reversible disease that might benefit from therapeutic interventions. OBJECTIVE: To evaluate whether Lung Clearance Index (LCI), Sacin & Scond, measuring global, intracinar & conductive ventilation inhomogeneity respectively, are more frequently abnormal than lung volumes in young people with SCA. METHODS: Nitrogen multiple breath washout, spirometry and body plethysmography were cross-sectionally evaluated at steady state in subjects with SCA (hemoglobin SS) and healthy controls aged 8-21 years from London, UK. RESULTS: 35 patients (51% boys; mean±SD 16.4±3.5 years) and 31 controls (48% boys; 16.2±3.2 years) were tested. There were significant differences between the study and control group in mean LCI (mean difference 0.42 units, 95%CI 0.22 to 0.63, p = 0.0001), Sacin (mean difference 0.014 units, 95%CI 0.001 to 0.026, p = 0.04), FEV1 (mean difference -0.79 z-scores, 95%CI -1.28 to -0.30, p = 0.002), FVC (mean difference -0.80 z-scores, 95%CI -1.28 to -0.31) and TLC (mean difference -0.79 z-scores, 95%CI -1.25 to -0.29), but not in Scond and FEV1/FVC ratio. While 29% (10/35) of patients had LCI >95th percentile of controls, 23% (8/35) had abnormal FEV1 (<5th of the reference population). CONCLUSION: Lung clearance index detected slightly more abnormalities than lung volumes in young people with SCA. Significant differences with controls in LCI and Sacin but not in Scond and FEV1/FVC ratio suggest that the lung function changes were most likely due to patchy peripheral lung disease

Lung Clearance Index May Detect Early Peripheral Lung Disease in Sickle Cell Anemia

RATIONALE: Chronic lung injury is common in sickle cell anemia (SCA) and worsens outcomes. Sensitive lung function tests might predict reversible disease that might benefit from therapeutic interventions. OBJECTIVE: To evaluate whether Lung Clearance Index (LCI), Sacin & Scond, measuring global, intracinar & conductive ventilation inhomogeneity respectively, are more frequently abnormal than lung volumes in young people with SCA. METHODS: Nitrogen multiple breath washout, spirometry and body plethysmography were cross-sectionally evaluated at steady state in subjects with SCA (hemoglobin SS) and healthy controls aged 8-21 years from London, UK. RESULTS: 35 patients (51% boys; mean±SD 16.4±3.5 years) and 31 controls (48% boys; 16.2±3.2 years) were tested. There were significant differences between the study and control group in mean LCI (mean difference 0.42 units, 95%CI 0.22 to 0.63, p = 0.0001), Sacin (mean difference 0.014 units, 95%CI 0.001 to 0.026, p = 0.04), FEV1 (mean difference -0.79 z-scores, 95%CI -1.28 to -0.30, p = 0.002), FVC (mean difference -0.80 z-scores, 95%CI -1.28 to -0.31) and TLC (mean difference -0.79 z-scores, 95%CI -1.25 to -0.29), but not in Scond and FEV1/FVC ratio. While 29% (10/35) of patients had LCI >95th percentile of controls, 23% (8/35) had abnormal FEV1 (<5th of the reference population). CONCLUSION: Lung clearance index detected slightly more abnormalities than lung volumes in young people with SCA. Significant differences with controls in LCI and Sacin but not in Scond and FEV1/FVC ratio suggest that the lung function changes were most likely due to patchy peripheral lung disease