Establishing construct validity of neuropsychological tests in cancer survivors.

OBJECTIVE: Cancer-related cognitive impairments (CRCI) are frequently reported among cancer survivors, and attention is the most frequently assessed cognitive domain in CRCI. However, there is no consensus as to whether attention is impaired. We suggest that a major reason for this lack of agreement is a lack of construct validity for neuropsychological attention tests. We propose to assess the construct validity of neuropsychological attention tests with respect to experimental paradigms from cognitive psychology. METHODS: Self-reported cancer survivors (N = 314) completed an online battery comprising six experimental attention paradigms and eight neuropsychological tests. Confirmatory factor analysis was used to evaluate the fit of five models derived from a general population sample (N = 636) in a previous study (M. Treviño, Cogn Res Princ Implic, in press). We then subjected the best-fitting model to a measurement invariance analysis. RESULTS: The best-fitting model was a six intercorrelated factor structure, comprising Capacity, Search, Digit Span, Arithmetic, Sustained Attention, and Flanker Interference factors. Configural and weak invariance held, indicating that the factor loadings were invariant across groups. Strong invariance, indicating that intercepts were also invariant, held except for the Approximate Number Sense test. CONCLUSIONS: According to our factor model, Spatial Span and Digit Symbol Coding measure attentional capacity, while the Trail Making Test (A&B) and Letter Cancellation tests measure visual search ability. However, Digit Span and Arithmetic tests do not measure attention. We hope that these results will lead to better scientific models, better patient education, and, ultimately, improved outcomes for survivors.

Making decisions about health information on social media: a mouse-tracking study.

Health misinformation is a problem on social media, and more understanding is needed about how users cognitively process it. In this study, participants' accuracy in determining whether 60 health claims were true (e.g., "Vaccines prevent disease outbreaks") or false (e.g., "Vaccines cause disease outbreaks") was assessed. The 60 claims were related to three domains of health risk behavior (i.e., smoking, alcohol and vaccines). Claims were presented as Tweets or as simple text statements. We employed mouse tracking to measure reaction times, whether processing happens in discrete stages, and response uncertainty. We also examined whether health literacy was a moderating variable. The results indicate that information in statements and tweets is evaluated incrementally most of the time, but with overrides happening on some trials. Adequate health literacy scorers were equally certain when responding to tweets and statements, but they were more accurate when responding to tweets. Inadequate scorers were more confident on statements than on tweets but equally accurate on both. These results have important implications for understanding the underlying cognition needed to combat health misinformation online.

Advancing Research on Medical Image Perception by Strengthening Multidisciplinary Collaboration.

Medical image interpretation is central to detecting, diagnosing, and staging cancer and many other disorders. At a time when medical imaging is being transformed by digital technologies and artificial intelligence, understanding the basic perceptual and cognitive processes underlying medical image interpretation is vital for increasing diagnosticians' accuracy and performance, improving patient outcomes, and reducing diagnostician burnout. Medical image perception remains substantially understudied. In September 2019, the National Cancer Institute convened a multidisciplinary panel of radiologists and pathologists together with researchers working in medical image perception and adjacent fields of cognition and perception for the "Cognition and Medical Image Perception Think Tank." The Think Tank's key objectives were to identify critical unsolved problems related to visual perception in pathology and radiology from the perspective of diagnosticians, discuss how these clinically relevant questions could be addressed through cognitive and perception research, identify barriers and solutions for transdisciplinary collaborations, define ways to elevate the profile of cognition and perception research within the medical image community, determine the greatest needs to advance medical image perception, and outline future goals and strategies to evaluate progress. The Think Tank emphasized diagnosticians' perspectives as the crucial starting point for medical image perception research, with diagnosticians describing their interpretation process and identifying perceptual and cognitive problems that arise. This article reports the deliberations of the Think Tank participants to address these objectives and highlight opportunities to expand research on medical image perception.

Visual Memory Scan Slopes: Their Changes over the First Two Seconds of Processing.

Using the prime-probe comparison paradigm, Jacob, Breitmeyer, and Treviño (2013) demonstrated that information processing in visual short-term memory (VSTM) proceeds through three stages: sensory visible persistence (SVP), nonvisible informational persistence (NIP), and visual working memory (VWM). To investigate the effect of increasing the memory load on these stages by using 1, 3, and 5 display items, measures of VSTM performance, including storage, storage-slopes, and scan-slopes, were obtained. Results again revealed three stages of VSTM processing, but with the NIP stage increasing in duration as memory load increased, suggesting a need, during the NIP stage, for transfer and encoding delays of information into VWM. Consistent with this, VSTM scan-slopes, in ms/item, were lowest during the first NIP stage, highest during the second NIP stage, and intermediate during the third, non-sensory VWM stage. The results also demonstrated a color-superiority effect, as all VSTM scan-slopes for color were lower than those for shape and as all VSTM storages for color are greater than those for shape, and the existence of systematic pair-wise correlations between all three measures of VSTM performance. These findings and their implications are related to other paradigms and methods used to investigate post-stimulus processing in VSTM.

How do we measure attention? Using factor analysis to establish construct validity of neuropsychological tests.

We investigated whether standardized neuropsychological tests and experimental cognitive paradigms measure the same cognitive faculties. Specifically, do neuropsychological tests commonly used to assess attention measure the same construct as attention paradigms used in cognitive psychology and neuroscience? We built on the "general attention factor", comprising several widely used experimental paradigms (Huang et al., 2012). Participants (n = 636) completed an on-line battery (TestMyBrain.org) of six experimental tests [Multiple Object Tracking, Flanker Interference, Visual Working Memory, Approximate Number Sense, Spatial Configuration Visual Search, and Gradual Onset Continuous Performance Task (Grad CPT)] and eight neuropsychological tests [Trail Making Test versions A & B (TMT-A, TMT-B), Digit Symbol Coding, Forward and Backward Digit Span, Letter Cancellation, Spatial Span, and Arithmetic]. Exploratory factor analysis in a subset of 357 participants identified a five-factor structure: (1) attentional capacity (Multiple Object Tracking, Visual Working Memory, Digit Symbol Coding, Spatial Span), (2) search (Visual Search, TMT-A, TMT-B, Letter Cancellation); (3) Digit Span; (4) Arithmetic; and (5) Sustained Attention (GradCPT). Confirmatory analysis in 279 held-out participants showed that this model fit better than competing models. A hierarchical model where a general cognitive factor was imposed above the five specific factors fit as well as the model without the general factor. We conclude that Digit Span and Arithmetic tests should not be classified as attention tests. Digit Symbol Coding and Spatial Span tap attentional capacity, while TMT-A, TMT-B, and Letter Cancellation tap search (or attention-shifting) ability. These five tests can be classified as attention tests.

Rapid perceptual processing in two- and three-dimensional prostate images.

Radiologists can identify whether a radiograph is abnormal or normal at above chance levels in breast and lung images presented for half a second or less. This early perceptual processing has only been demonstrated in static two-dimensional images (e.g., mammograms). Can radiologists rapidly extract the "gestalt" from more complex imaging modalities? For example, prostate multiparametric magnetic resonance imaging (mpMRI) displays a series of images as a virtual stack and comprises multiple imaging sequences: anatomical information from the T2-weighted (T2W) sequence, functional information from diffusion-weighted imaging, and apparent diffusion coefficient sequences. We first tested rapid perceptual processing in static T2W images then among the two functional sequences. Finally, we examined whether this rapid radiological perception could be observed using T2W multislice imaging. Readers with experience in prostate mpMRI could detect and localize lesions in all sequences after viewing a 500-ms static image. Experienced prostate readers could also detect and localize lesions when viewing multislice image stacks presented as brief movies, with image slices presented at either 48, 96, or 144 ms. The ability to quickly extract the perceptual gestalt may be a general property of expert perception, even in complex imaging modalities.

Interactions between visual working memory and visual attention among survivors of pediatric acute lymphoblastic leukemia (ALL) and their healthy peers.

Introduction: There is increasing concern for adverse cognitive late effects among survivors of pediatric acute lymphoblastic leukemia (ALL) given the widespread impact they have on academic achievement, particularly working memory and attention. We assessed performance among survivors and their healthy peers on a dual task paradigm measuring visual working memory (VWM) and visual attention independently and the dynamic relationship between the two. Assessing specific subsets within cognitive domains allows for understanding the distinct nature of cognitive impairments. Method: Participants were 34 survivors of ALL who have been off-treatment and disease free for 7.5 years; and 20 healthy controls, all between the ages of 10 and 18 years. We utilized behavioral single- and dual-task paradigms. In the dual tasks, participants maintained several items in VWM while performing a visual attention task (Eriksen Flanker Task) that required processing of a target stimulus while inhibiting the processing of distractor stimuli. The single tasks involved performing only the VWM task or only the visual attention task. Results: Results revealed survivors of ALL performed significantly worse than their healthy peers on the single visual attention task but not the single VWM task. Of particular interest, group differences were obtained on the dual VWM and visual attention tasks, such that the VWM and attention tasks reciprocally interfered with each other only among survivors and not their healthy peers. Conclusions: Our results highlight a core deficit in visual attention that is exacerbated by VWM demands among survivors of ALL. The implementation of tasks from cognitive neuroscience paradigms may be sensitive to cognitive impairments experienced by cancer survivors. Assessment and intervention practices among survivors of pediatric ALL are discussed.

Understanding the Profile of Cancer-Related Cognitive Impairments: A Critique of Meta-Analyses.

A large body of evidence indicates that cancer survivors who have undergone chemotherapy have cognitive impairments. Substantial disagreement exists regarding which cognitive domains are impaired in this population. We suggest that is in part due to inconsistency in how neuropsychological tests are assigned to cognitive domains. The purpose of this paper is to critically analyze the meta-analytic literature on cancer-related cognitive impairments (CRCI) to quantify this inconsistency. We identified all neuropsychological tests reported in seven meta-analyses of the CRCI literature. Although effect sizes were generally negative (indicating impairment), every domain was declared to be impaired in at least one meta-analysis and unimpaired in at least one other meta-analysis. We plotted summary effect sizes from all the meta-analyses and quantified disagreement by computing the observed and ideal distributions of the one-way χ2 statistic. The actual χ2 distributions were noticeably more peaked and shifted to the left than the ideal distributions, indicating substantial disagreement among the meta-analyses in how neuropsychological tests were categorized to domains. A better understanding of the profile of impairments in CRCI is essential for developing effective remediation methods. To accomplish this goal, the research field needs to promote better agreement on how to measure specific cognitive functions.

A Call for a Neuroscience Approach to Cancer-Related Cognitive Impairment.

Cancer-related cognitive impairment (CRCI) is a widespread problem for the increasing population of cancer survivors. Our understanding of the nature, causes, and prevalence of CRCI is hampered by a reliance on clinical neuropsychological methods originally designed to detect focal lesions. Future progress will require collaboration between neuroscience and clinical neuropsychology.

Temporal and spatial fluctuations of groundwater-derived alkalinity fluxes to a semiarid coastal embayment.

We conducted a comprehensive analysis of a variety of geochemical data including total alkalinity (TA), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), major ions, stable isotopes, and submarine groundwater discharge, to understand biogeochemical and hydrologic processes driving the seasonal to annual estuarine buffering capacity in Nueces Bay, Texas. These measurements, together with statistical analysis and geochemical modeling, show large variability of freshwater influence. TA consumption, common to spring seasons, was mainly driven by CaCO3 precipitation and, to some extent, by aerobic respiration. TA production occurred in some parts of the bay during summer, fall and winter, likely driven by denitrification. CaCO3 dissolution is stimulated by input of undersaturated river waters following significant flooding events. Since consumption and production of TA was not necessarily associated with different salinity zones, SGD, identified to be significant year-round, likely offsets the effects of salinity changes. Net DIC and TA fluxes exceeded dissolved organic carbon flux by an order of magnitude, except for winter 2014 when it was in the same order of magnitude. In addition to generally larger SGD rates when compared to other studies, production of TA (DIC and DOC) in the bottom sediments, as observed in this study, leads to larger fluxes, especially for the driest season (winter 2014), in the mid-bay area (6.27·106µMm-2d-1). Consistently larger inputs occur along the shoreline stations (6.14·106µMm-2d-1) following the flood recession, when compared to mid-bay (1.26·106µMm-2d-1) and are associated with lower SGD following the summer 2015 flooding. This study demonstrates that the carbonate chemistry of estuaries in semiarid areas is affected by non-conservative processes because of seasonal variability of hydroclimatic conditions.

Tracking the first two seconds: three stages of visual information processing?

We compared visual priming and comparison tasks to assess information processing of a stimulus during the first 2 s after its onset. In both tasks, a 13-ms prime was followed at varying SOAs by a 40-ms probe. In the priming task, observers identified the probe as rapidly and accurately as possible; in the comparison task, observers determined as rapidly and accurately as possible whether or not the probe and prime were identical. Priming effects attained a maximum at an SOA of 133 ms and then declined monotonically to zero by 700 ms, indicating reliance on relatively brief visuosensory (iconic) memory. In contrast, the comparison effects yielded a multiphasic function, showing a maximum at 0 ms followed by a minimum at 133 ms, followed in turn by a maximum at 240 ms and another minimum at 720 ms, and finally a third maximum at 1,200 ms before declining thereafter. The results indicate three stages of prime processing that we take to correspond to iconic visible persistence, iconic informational persistence, and visual working memory, with the first two used in the priming task and all three in the comparison task. These stages are related to stages presumed to underlie stimulus processing in other tasks, such as those giving rise to the attentional blink.

Neurogenesis, exercise, and cognitive late effects of pediatric radiotherapy.

Brain cancer is a common type of childhood malignancy, and radiotherapy (RT) is a mainstay of treatment. RT is effective for tumor eradication, and survival rates are high. However, RT damages the brain and disrupts ongoing developmental processes, resulting in debilitating cognitive "late" effects that may take years to fully manifest. These late effects likely derive from a long-term decrement in cell proliferation, combined with a neural environment that is hostile to plasticity, both of which are induced by RT. Long-term suppression of cell proliferation deprives the brain of the raw materials needed for optimum cognitive performance (such as new neurons in the hippocampus and new glia in frontal cortex), while chronic inflammation and dearth of trophic substances (such as growth hormone) limit neuroplastic potential in existing circuitry. Potential treatments for cognitive late effects should address both of these conditions. Exercise represents one such potential treatment, since it has the capacity to enhance cell proliferation, as well as to promote a neural milieu permissive for plasticity. Here, we review the evidence that cognitive late effects can be traced to RT-induced suppression of cell proliferation and hostile environmental conditions, as well as emerging evidence that exercise may be effective as an independent or adjuvant therapy.