Retooling computational techniques for EEG-based neurocognitive modeling of children's data, validity and prospects for learning and education

This paper describes continuing research on the building of neurocognitive models of the internal mental and brain processes of children using a novel adapted combination of existing computational approaches and tools, and using electro-encephalographic (EEG) data to validate the models. The guiding working model which was pragmatically selected for investigation was the established and widely used Adaptive Control of Thought-Rational (ACT-R) modeling architecture from cognitive science. The anatomo-functional circuitry covered by ACT-R is validated by MRI-based neuroscience research. The present experimental data was obtained from a cognitive neuropsychology study involving preschool children (aged 46), which measured their visual selective attention and word comprehension behaviors. The collection and analysis of Event-Related Potentials (ERPs) from the EEG data allowed for the identification of sources of electrical activity known as dipoles within the cortex, using a combination of computational tools (Independent Component Analysis, FASTICA; EEG-Lab DIPFIT). The results were then used to build neurocognitive models based on Python ACT-R such that the patterns and the timings of the measured EEG could be reproduced as simplified symbolic representations of spikes, built through simplified electric-field simulations. The models simulated ultimately accounted for more than three-quarters of variations spatially and temporally in all electrical potential measurements (fit of model to dipole data expressed as R 2 ranged between 0.75 and 0.98; P < 0.0001). Implications for practical uses of the present work are discussed for learning and educational applications in non-clinical and special needs children's populations, and for the possible use of non-experts (teachers and parents)

Re-operation of idiopathic full-thickness macular holes after initial surgery with internal limiting membrane peel

Background/aims: A retrospective consecutive case series to evaluate the efficacy of re-operation in patients with persistent or recurrent idiopathic full-thickness macular hole after initial surgery with internal limiting membrane peel (ILM). Methods: 491 patients underwent surgery for fullthickness macular hole from January 2004 to November 2007. Fifty-five patients either did not close or reopened during the follow-up period. Thirty patients with initial ILM peel underwent repeat surgery involving vitrectomy, enlargement of ILM rhexis and gas tamponade. Results: Anatomical closure rate was 88.8% for primary surgery and 46.7% (14/30) for re-operation. There was a statistically significant improvement in overall best corrected visual acuity (BCVA) from re-operation baseline BCVA (p=0.02) within 1 year. For holes that did not close after the second surgery, visual acuity did not worsen. Conclusion: Re-operation has a reduced success rate of anatomical closure. However, BCVA is statistically significantly improved from re-operation baseline, so even though we cannot return vision to pre-pathological baseline, re-operation can improve on this new baseline.Link_to_subscribed_fulltex

Retooling Computational Techniques for EEG-Based Neurocognitive Modeling of Children's Data, Validity and Prospects for Learning and Education

This paper describes continuing research on the building of neurocognitive models of the internal mental and brain processes of children using a novel adapted combination of existing computational approaches and tools, and using electro-encephalographic (EEG) data to validate the models. The guiding working model which was pragmatically selected for investigation was the established and widely used Adaptive Control of Thought-Rational (ACT-R) modeling architecture from cognitive science. The anatomo-functional circuitry covered by ACT-R is validated by MRI-based neuroscience research. The present experimental data was obtained from a cognitive neuropsychology study involving preschool children (aged 4–6), which measured their visual selective attention and word comprehension behaviors. The collection and analysis of Event-Related Potentials (ERPs) from the EEG data allowed for the identification of sources of electrical activity known as dipoles within the cortex, using a combination of computational tools (Independent Component Analysis, FASTICA; EEG-Lab DIPFIT). The results were then used to build neurocognitive models based on Python ACT-R such that the patterns and the timings of the measured EEG could be reproduced as simplified symbolic representations of spikes, built through simplified electric-field simulations. The models simulated ultimately accounted for more than three-quarters of variations spatially and temporally in all electrical potential measurements (fit of model to dipole data expressed as R2 ranged between 0.75 and 0.98; P &lt; 0.0001). Implications for practical uses of the present work are discussed for learning and educational applications in non-clinical and special needs children's populations, and for the possible use of non-experts (teachers and parents)

Cognitive control, bedtime patterns, and testing time in female adolescent students: behavioral and neuro-electrophysiological correlates

IntroductionShorter and/or disrupted sleep during adolescence is associated with cognitive and mental health risks, particularly in females. We explored the relationship between bedtime behavior patterns co-varying with Social Jet Lag (SJL) and School Start Times (SST) and neurocognitive performance in adolescent female students.MethodsTo investigate whether time of day (morning vs. afternoon), early SSTs and days of the school week can be correlated with neurocognitive correlates of sleep insufficiency, we recruited 24 female students aged 16–18 to report sleep logs, and undergo event-related electroencephalographic recordings on Monday, Wednesday, mornings, and afternoons. Using a Stroop task paradigm, we analyzed correlations between reaction times (RTs), accuracy, time of day, day of week, electroencephalographic data, and sleep log data to understand what relationships may exist.ResultsParticipants reported a 2-h sleep phase delay and SJL. Stroop interference influenced accuracy on Monday and Wednesday similarly, with better performance in the afternoon. For RTs, the afternoon advantage was much larger on Monday than Wednesday. Midline Event-Related Potentials (ERPs) yielded higher amplitudes and shorter latencies on Wednesday morning and Monday afternoon, in time windows related to attention or response execution. A notable exception were delayed ERP latencies on Wednesday afternoon. The latter could be explained by the fact that delta EEG waves tended to be the most prominent, suggesting heightened error monitoring due to accumulating mental fatigue.DiscussionThese findings provide insights into the interaction between SJL and SST and suggest evidence-based criteria for planning when female adolescents should engage in cognitive-heavy school activities such as tests or exams

Understanding macular holes that develop after repair of retinal detachment

Objective: To present the characteristics and outcomes of macular holes (MHs) that arise in eyes that have been treated for retinal detachment (RD). Design: Retrospective, interventional, consecutive case series. Participants: We studied 18 eyes that developed a MH following RD repair. Methods: We report the demographic and clinical characteristics, MH closure rates, and best corrected visual acuity (BCVA) following MH repair. Results: We detected 18 full-thickness MHs in 985 eyes. In 14 of 18, the original RD involved the macula, and in 16 of 18, the BCVA was 20/200 or worse. Of the RDs, 8 of 18 required multiple procedures to achieve reattachment. Post-RD BCVA was 20/200 or worse in 15 of 18 patients. The median time to MH diagnosis after RD repair was 1 month (range, 2 days to 53 months), and from MH diagnosis to MH repair, the median time was 1.75 months (range, 3 weeks to 8 months). Of 16 eyes (89%) that underwent surgical repair of the MH, 14 achieved MH closure, 1 requiring multiple pars plana vitrectomy, and 11 saw at least 1 Snellen line of improvement (median, 1; range, 1 to 6); 2 lost vision (1 and 2 Snellen lines, respectively); and 3 remained unchanged at a median follow-up of 3 months (range, 1 month to 25 months). Of the 18 patients, 6 had at least 20/80 BCVA at last follow-up. Conclusions: MHs following RDs (incidence 1.9%) are likely to be macula-off RDs requiring multiple interventions for RD repair. Post-MH-repair closure rates are similar to the rates for idiopathic MHs. BCVA outcomes are moderate and are dependent on impairment post-RD repair. The findings suggest other pathogenic mechanisms besides vitreofoveal traction may be leading to these MHs. © 2012 Canadian Ophthalmological Society.Link_to_subscribed_fulltex

Pneumatic displacement of submacular hemorrhage [6] (multiple letters)

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Predictors of treatment failure for pneumatic retinopexy

Objective: The purpose of this study was to define the overall anatomic success rate in pneumatic retinopexy and to identify morphologic features that may be predictive of treatment failure in pneumatic retinopexy. Design and Participants: Prospective consecutive interventional case series of patients with new-onset primary rhegmatogenous retinal detachments treated with pneumatic retinopexy. Methods: In this interventional case series, consecutive patients with new-onset primary rhegmatogenous retinal detachments were treated with pneumatic retinopexy and followed prospectively. Morphologic data were collected on 3-colour fundus drawings. The primary outcome measure was treatment failure, defined as requirement for scleral buckle or vitrectomy within the follow-up period. Rates of failure for each morphologic feature were compared and a logistic regression model was fit. Results: A total of 113 eyes were included in the study. Anatomic success was achieved in 69.6% of patients. Morphologic criteria including the position and number of breaks, position and extent of lattice degeneration, size of the detached area, and macular status were all found not to be significantly related to failure. In multivariate analysis, only 3 predictors, pseudophakic status (p < 0.05, odds ratio [OR] 2.9, 95% CI, 1.06-7.88), presence of retinal break greater than 1 clock-hour (p < 0.05, OR 3.41, 1.06-11.02), and presence of grade C or D proliferative vitreoretinopathy (PVR) (p < 0.01, OR 31.83, 95% CI, 3.59-282.24), gained statistical significance. Conclusions: Only pseudophakia, a large retinal break, and/or PVR was associated with an increased likelihood of failure. © 2013 Canadian Ophthalmological Society. All rights reserved.Link_to_subscribed_fulltex

Incidence of endophthalmitis and use of antibiotic prophylaxis after intravitreal injections

Purpose: To report the incidence of endophthalmitis in association with different antibiotic prophylaxis strategies after intravitreal injections of anti-vascular endothelial growth factors and triamcinolone acetonide. Design: Retrospective, comparative case series. Participants: Fifteen thousand eight hundred ninety-five intravitreal injections (9453 ranibizumab, 5386 bevacizumab, 935 triamcinolone acetonide, 121 pegaptanib sodium) were reviewed for 2465 patients between January 5, 2005, and August 31, 2010. The number of injections was determined from billing code and patient records. Methods: The indications for injection included age-related macular degeneration, diabetic macular edema, central and branch retinal vein occlusion, and miscellaneous causes. Three strategies of topical antibiotic prophylaxis were used by the respective surgeons: (1) antibiotics given for 5 days after each injection, (2) antibiotics given immediately after each injection, and (3) no antibiotics given. Main Outcome Measures: The primary outcome measures were the incidence of culture-positive endophthalmitis and culture-negative cases of suspected endophthalmitis. Results: Nine eyes of 9 patients with suspected endophthalmitis after injection were identified. Three of the 9 cases had culture-positive results. The overall incidence of endophthalmitis was 9 in 15 895. The incidence of culture-negative cases of suspected endophthalmitis and culture-proven endophthalmitis after injection was 6 in 15 895 and 3 in 15 895, respectively. Taking into account both culture-positive endophthalmitis and culture-negative cases of suspected endophthalmitis, the incidence per injection was 5 in 8259 for patients who were given antibiotics for 5 days after injection, 2 in 2370 for those who received antibiotics immediately after each injection, and 2 in 5266 who received no antibiotics. However, if considering culture-proven endophthalmitis alone, the use of topical antibiotics, given immediately or for 5 days after injection, showed lower rates of endophthalmitis compared with those without postinjection antibiotics. The risk of endophthalmitis after intravitreal injection varied among agents that were used. Among the 9 cases of clinically suspected endophthalmitis, regardless of prophylactic strategies used, the incidence of endophthalmitis per injection was 2 in 935 for triamcinolone acetonide, 3 in 9453 for ranibizumab, and 4 in 5386 for bevacizumab. Conclusions: The overall rate of intravitreal injection-related endophthalmitis is greater with the use of topical antibiotics, given immediately or for 5 days after the injection, compared with no antibiotics. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2012 American Academy of Ophthalmology.Link_to_subscribed_fulltex

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