Near-infrared spectroscopy during cardiopulmonary resuscitation for pediatric cardiac arrest: A prospective, observational study.

AIM: Cerebral oxygenation (rSO2) is not routinely measured during pediatric cardiopulmonary resuscitation (CPR). We aimed to determine whether higher intra-arrest rSO2 was associated with return of spontaneous circulation (ROSC) and survival to hospital discharge. METHODS: Prospective, single-center observational study of cerebral oximetry using near-infrared spectroscopy (NIRS) during pediatric cardiac arrest from 2016 to 2020. Eligible patients had ≥30 s of rSO2 data recorded during CPR. We compared median rSO2 and percentage of rSO2 measurements above a priori thresholds for the entire event and the final five minutes of the CPR event between patients with and without ROSC and survival to discharge. RESULTS: Twenty-one patients with 23 CPR events were analyzed. ROSC was achieved in 17/23 (73.9%) events and five/21 (23.8%) patients survived to discharge. The median rSO2 was higher for events with ROSC vs. no ROSC for the overall event (62% [56%, 70%] vs. 45% [35%, 51%], p = 0.025) and for the final 5 minutes of the event (66% [55%, 72%] vs. 43% [35%, 44%], p = 0.01). Patients with ROSC had a higher percentage of measurements above 50% during the final five minutes of CPR (100% [100%, 100%] vs. 0% [0%, 29%], p = 0.01). There was no association between rSO2 and survival to discharge. CONCLUSIONS: Higher cerebral rSO2 during CPR for pediatric cardiac arrest was associated with higher rates of ROSC but not with survival to discharge.

Practical approaches to incidental findings in brain imaging research.

A decade of empirical work in brain imaging, genomics, and other areas of research has yielded new knowledge about the frequency of incidental findings, investigator responsibility, and risks and benefits of disclosure. Straightforward guidance for handling such findings of possible clinical significance, however, has been elusive. In early work focusing on imaging studies of the brain, we suggested that investigators and institutional review boards must anticipate and articulate plans for handling incidental findings. Here we provide a detailed analysis of different approaches to the problem and evaluate their merits in the context of the goals and setting of the research and the involvement of neurologists, radiologists, and other physicians. Protecting subject welfare and privacy, as well as ensuring scientific integrity, are the highest priorities in making choices about how to handle incidental findings. Forethought and clarity will enable these goals without overburdening research conducted within or outside the medical setting.

Gating of human theta oscillations by a working memory task.

Electrode grids on the cortical surface of epileptic patients provide a unique opportunity to observe brain activity with high temporal-spatial resolution and high signal-to-noise ratio during a cognitive task. Previous work showed that large-amplitude theta frequency oscillations occurred intermittently during a maze navigation task, but it was unclear whether theta related to the spatial or working memory components of the task. To determine whether theta occurs during a nonspatial task, we made recordings while subjects performed the Sternberg working memory task. Our results show event-related theta and reveal a new phenomenon, the cognitive "gating" of a brain oscillation: at many cortical sites, the amplitude of theta oscillations increased dramatically at the start of the trial, continued through all phases of the trial, including the delay period, and decreased sharply at the end. Gating could be seen in individual trials and varying the duration of the trial systematically varied the period of gating. These results suggest that theta oscillations could have an important role in organizing multi-item working memory.

Optic flow helps humans learn to navigate through synthetic environments.

Self-movement through an environment generates optic flow, a potential source of heading information. But it is not certain that optic flow is sufficient to support navigation, particularly navigation along complex, multi-legged paths. To address this question, we studied human participants who navigated synthetic environments with and without salient optic flow. Participants used a keyboard to control realistic simulation of self-movement through computer-rendered, synthetic environments. Because these environments comprised series of identically textured virtual corridors and intersections, participants had to build up some mental representation of the environment in order to perform. The impact of optic flow on learning was examined in two experiments. In experiment 1, participants learned to navigate multiple T-junction mazes with and without accompanying optic flow. Optic flow promoted faster learning, mainly by preventing disorientation and backtracking in the maze. In experiment 2, participants found their way around a virtual city-block environment, experiencing two different kinds of optic flow as they went. By varying the rate at which the display was updated, we created optic flow that was either fluid or choppy. Here, fluid optic flow (as compared with choppy optic flow) enabled participants to locate a remembered target position more accurately. When other cues are unavailable, optic flow can be a significant aid in wayfinding. Among other things, optic flow can facilitate path integration, which involves updating a mental representation of place by combining the trajectories of previously travelled paths [corrected].

The necessary field of view to read with an optimal stand magnifier.

BACKGROUND: For most people with low vision, some form of magnification is necessary to read. Using a magnifier reduces the number of letters that can be seen simultaneously (field of view), which has been shown to decrease reading rates. This study sought to determine how many letters are necessary to attain maximal reading rates with a stand magnifier. METHODS: Younger and older normally-sighted and visually-impaired observers read short passages using a fiber optic stand magnifier (taper). The optical properties of this magnifier allowed the field of view to be precisely varied. Each subject read using at least four field sizes (3, 5, 9 and 13 characters visible) while reading speed was measured. RESULTS: Reading rates continued to increase with as many as 13 characters visible, regardless of age or vision status. In addition, reading with the taper was slower for all subject groups than reading without the magnifier. CONCLUSIONS: This study confirms reports that reading rates increase as the field of view increases when reading from a page of text. The need for this large field of view relative to other low vision reading aids (i.e., computer-generated scroll displays) is likely the result of the readers' need to actively navigate across the page of text.