Sleep spindles, a prominent feature of the non-rapid eye movement (NREM) sleep electroencephalogram (EEG), are linked to cognitive abilities. Early childhood is a time of rapid cognitive and neurophysiological maturation; however, little is known about developmental changes in sleep spindles. In this study, we longitudinally examined trajectories of multiple sleep spindle characteristics (i.e., spindle duration, frequency, integrated spindle amplitude, and density) and power in the sigma frequency range (10–16 Hz) across ages 2, 3, and 5 years (n = 8; 3 males). At each time point, nocturnal sleep EEG was recorded in-home after 13-h of prior wakefulness. Spindle duration, integrated spindle amplitude, and sigma power increased with age across all EEG derivations (C3A2, C4A1, O2A1, and O1A2; all ps < 0.05). We also found a developmental decrease in mean spindle frequency (p < 0.05) but no change in spindle density with increasing age. Thus, sleep spindles increased in duration and amplitude but decreased in frequency across early childhood. Our data characterize early developmental changes in sleep spindles, which may advance understanding of thalamocortical brain connectivity and associated lifelong disease processes. These findings also provide unique insights into spindle ontogenesis in early childhood and may help identify electrophysiological features related to healthy and aberrant brain maturation.

SUMMARY Although all young children nap, the neurophysiological features and associated developmental trajectories of daytime sleep remain largely unknown. Longitudinal studies of napping physiology are fundamental to understanding sleep regulation during early childhood, a sensitive period in brain and behaviour development and a time when children transition from a biphasic to a monophasic sleep–wakefulness pattern. We investigated daytime sleep in eight healthy children with sleep electroencephalography (EEG) assessments at three longitudinal points: 2 years (2.5–3.0 years), 3 years (3.5–4.0 years) and 5 years (5.5–6.0 years). At each age, we measured nap EEG during three randomized conditions: after 4 h (morning nap), 7 h (afternoon nap) and 10 h (evening nap) duration of prior wakefulness. Developmental changes in sleep were most prevalent in the afternoon nap (e.g. decrease in sleep duration by 30 min from 2 to 3 years and by 20 min from 3 to 5 years). In contrast, nap sleep architecture (% of sleep stages) remained unchanged across age. Maturational changes in non-rapid eye movement sleep EEG power were pronounced in the slow wave activity (SWA, 0.75–4.5 Hz), theta (4.75–7.75 Hz) and sigma (10–15 Hz) frequency ranges. These findings indicate that the primary marker of sleep depth, SWA, is less apparent in daytime naps as children mature. Moreover, our fundamental data provide insight into associations between sleep regulation and functional modifications in the central nervous system during early childhood.

No abstract

Introduction Glaucoma is the leading cause of irreversible blindness worldwide and is often undetected in resource-limited settings. Early screening and treatment of elevated intraocular pressure (IOP) reduces both the development and progression of visual field defects. IOP screening in developing countries is limited by access to ophthalmic equipment, trained ophthalmic staff, and follow up. High-volume cataract surgery outreaches in resource-limited countries provide ample opportunity for glaucoma screening, intervention and follow up. Methods This prospective cross-sectional study took place during a cataract outreach campaign sponsored by the Himalayan Cataract Project (HCP) in partnership with Felege Hiwot Hospital in Bahir Dar, Ethiopia, during April 5th – April 10th 2021. IOP was measured on the surgical eye of patients before undergoing small incision cataract surgery (SICS) using rebound tonometry with an iCare tonometer model IC100. Results Intraocular pressure (IOP) was measured in 604 eyes of 595 patients who received SICS. Mean IOP was 12.1 mmHg (SD = 5.0 mmHg). A total of 29 patients had an IOP greater than 21 mmHg representing 4.8% of total IOP measurements. A total of 17 patients received oral acetazolamide prior to surgery to acutely lower IOP. Six of these patients had their surgery delayed due to elevated IOP and 9 patients received excisional goniotomy at the time of SICS. A temporal approach during SCIS was taken for all patients with elevated IOP to allow for possible trabeculectomy at a future date. Discussion IOP screening during high-volume cataract outreach campaigns can be performed safely, accurately and on a large scale with minimal resources and supplemental training. Pre-operative IOP measurement can improve surgical care at the time of cataract surgery as well as help establish long-term follow up for patients with glaucoma.

Introduction: Glaucoma is the leading cause of irreversible blindness worldwide and is often undetected in resource-limited settings. Early screening and treatment of elevated intraocular pressure (IOP) reduces both the development and progression of visual field defects. IOP screening in developing countries is limited by access to ophthalmic equipment, trained ophthalmic staff, and follow up. High-volume cataract surgery outreaches in resource-limited countries provide ample opportunity for glaucoma screening, intervention and follow up. Methods: This prospective cross-sectional study took place during a cataract outreach campaign sponsored by the Himalayan Cataract Project (HCP) in partnership with Felege Hiwot Hospital in Bahir Dar, Ethiopia, during April 5th – April 10th 2021. IOP was measured on the surgical eye of patients before undergoing small incision cataract surgery (SICS) using rebound tonometry with an iCare tonometer model IC100.Results: Intraocular pressure (IOP) was measured in 604 eyes of 595 patients who received SICS. Mean IOP was 12.1 mmHg (SD = 5.0 mmHg). A total of 29 patients had an IOP greater than 21 mmHg representing 4.8% of total IOP measurements. A total of 17 patients received oral acetazolamide prior to surgery to acutely lower IOP. Six of these patients had their surgery delayed due to elevated IOP and 9 patients received excisional goniotomy at the time of SICS. A temporal approach during SCIS was taken for all patients with elevated IOP to allow for possible trabeculectomy at a future date.Discussion: IOP screening during high-volume cataract outreach campaigns can be performed safely, accurately and on a large scale with minimal resources and supplemental training. Pre-operative IOP measurement can improve surgical care at the time of cataract surgery as well as help establish long-term follow up for patients with glaucoma.