How denialist amplification spread COVID misinformation and undermined the credibility of public health science

Denialist scientists played an outsized role in shaping public opinion and determining public health policy during the recent COVID pandemic. From early on, amplification of researchers who denied the threat of COVID shaped public opinion and undermined public health policy. The forces that amplify denialists include (1) Motivated amplifiers seeking to protect their own interests by supporting denialist scientists, (2) Conventional media outlets giving disproportionate time to denialist opinions, (3) Promoters of controversy seeking to gain traction in an 'attention economy,' and (4) Social media creating information silos in which denialists can become the dominant voice. Denialist amplification poses an existential threat to science relevant to public policy. It is incumbent on the scientific community to create a forum to accurately capture the collective perspective of the scientific community related to public health policy that is open to dissenting voices but prevents artificial amplification of denialists.

Absorption of wireless radiation in the child versus adult brain and eye from cell phone conversation or virtual reality

Children's brains are more susceptible to hazardous exposures, and are thought to absorb higher doses of radiation from cell phones in some regions of the brain. Globally the numbers and applications of wireless devices are increasing rapidly, but since 1997 safety testing has relied on a large, homogenous, adult male head phantom to simulate exposures; the "Standard Anthropomorphic Mannequin" (SAM) is used to estimate only whether tissue temperature will be increased by more than 1 Celsius degree in the periphery. The present work employs anatomically based modeling currently used to set standards for surgical and medical devices, that incorporates heterogeneous characteristics of age and anatomy. Modeling of a cell phone held to the ear, or of virtual reality devices in front of the eyes, reveals that young eyes and brains absorb substantially higher local radiation doses than adults'. Age-specific simulations indicate the need to apply refined methods for regulatory compliance testing; and for public education regarding manufacturers' advice to keep phones off the body, and prudent use to limit exposures, particularly to protect the young.

Recent diarrhea is associated with elevated salivary IgG responses to Cryptosporidium in residents of an eastern Massachusetts community

BACKGROUND

Serological data suggest that Cryptosporidium infections are common but underreported. The invasiveness of blood sampling limits the application of serology in epidemiological surveillance. We pilot-tested a non-invasive salivary anti-Cryptosporidium antibody assay in a community survey involving children and adults.

MATERIALS AND METHODS

Families with children were recruited in a Massachusetts community in July; symptoms data were collected at 3 monthly follow-up mail surveys. One saliva sample per person (n = 349) was collected via mail, with the last survey in October. Samples were analyzed for IgG and IgA responses to a recombinant C. hominis gp15 sporozoite protein using a time-resolved fluorometric immunoassay. Log-transformed assay results were regressed on age using penalized B-splines to account for the strong age-dependence of antibody reactions. Positive responses were defined as fluorescence values above the upper 99% prediction limit.

RESULTS

Forty-seven (13.5%) individuals had diarrhea without concurrent respiratory symptoms during the 3-month-long follow-up; eight of them had these symptoms during the month prior to saliva sampling. Two individuals had positive IgG responses: an adult who had diarrhea during the prior month and a child who had episodes of diarrhea during each survey month (Fisher's exact test for an association between diarrhea and IgG response: p = 0.0005 for symptoms during the prior month and p = 0.02 for symptoms during the entire follow-up period). The child also had a positive IgA response, along with two asymptomatic individuals (an association between diarrhea and IgA was not significant).

CONCLUSION

These results suggest that the salivary IgG specific to Cryptosporidium antigens warrants further evaluation as a potential indicator of recent infections.

Sexual selection, redundancy and survival of the most beautiful

A model is described of a highly redundant complex organism that has overlapping banks of genes such that each vital function is specified by several different genetic systems. This generates a synergistic profile linking probability of survival to the number of deleterious mutations in the genome. Computer models show that there is a dynamic interaction between the mean number of new deleterious mutations per generation (X), the mean number of deleterious mutations in the genome of the population (Y) and percentage zygote survival (Zs). Increased X leads to increased Y and a fall in Zs but it takes several generations before a new equilibrium is reached. If sexual attraction is influenced by the number of deleterious mutations in the genome of individuals then Y is reduced and Zs increased for any given value of X. This fall in Y and rise in Zs is more marked in polygamous than monogamous mating systems. The model is specified such that deleterious mutations can occur without any observable or measurable effect on function. Thus sexual selection, in this organism, for low levels of deleterious mutations cannot be based on assessment of performance. Instead it is based on a simple symmetrical surface pattern that is flawlessly reproduced by organisms with no deleterious mutations, but is less than perfect, and therefore less attractive, if genetic systems have been deleted. A complex vital task requires a system with a high level of redundancy that acts so that the loss of one component has no observable effect and therefore cannot be used for sexual selection. The reproduction of a beautiful surface pattern also requires a low error, high redundancy genetic system; however, in this case there is advantage if a single deleterious mutation produces a recognisable change. This leads to the conclusion that sexual selection and sexual attraction should be based on beauty rather than utility, and explains the common observation in nature that it is the most beautiful that survive.

Quantum adiabatic optimization and combinatorial landscapes

In this paper we analyze the performance of the Quantum Adiabatic Evolution algorithm on a variant of the satisfiability problem for an ensemble of random graphs parametrized by the ratio of clauses to variables, gamma=M/N . We introduce a set of macroscopic parameters (landscapes) and put forward an ansatz of universality for random bit flips. We then formulate the problem of finding the smallest eigenvalue and the excitation gap as a statistical mechanics problem. We use the so-called annealing approximation with a refinement that a finite set of macroscopic variables (instead of only energy) is used, and are able to show the existence of a dynamic threshold gamma= gamma(d) starting with some value of K -the number of variables in each clause. Beyond the dynamic threshold, the algorithm should take an exponentially long time to find a solution. We compare the results for extended and simplified sets of landscapes and provide numerical evidence in support of our universality ansatz. We have been able to map the ensemble of random graphs onto another ensemble with fluctuations significantly reduced. This enabled us to obtain tight upper bounds on the satisfiability transition and to recompute the dynamical transition using the extended set of landscapes.

The conservation of redundancy in genetic systems: effects of sexual and asexual reproduction

The relationship between probability of survival and the number of deleterious mutations in the genome is investigated using three different models of highly redundant systems that interact with a threatening environment. Model one is a system that counters a potentially lethal infection; it has multiple identical components that act in sequence and in parallel. Model two has many different overlapping components that provide threefold coverage of a large number of vital functions. The third model is based on statistical decision theory: an ideal detector, following an optimum decision strategy, makes crucial decisions in an uncertain world. The probability of a fatal error is reduced by a redundant sampling system, but the chance of error rises as the system is impaired by deleterious mutations. In all three cases the survival profile shows a synergistic pattern in that the probability of survival falls slowly and then more rapidly. This is different than the multiplicative or independent survival profile that is often used in mathematical models. It is suggested that a synergistic profile is a property of redundant systems. Model one is then used to study the conservation of redundancy during sexual and asexual reproduction. A unicellular haploid organism reproducing asexually retains redundancy when the mutation rate is very low (0.001 per cell division), but tends to lose high levels of redundancy if the mutation rate is increased (0.01 to 0.1 per cell division). If a similar unicellular haploid organism has a sexual phase then redundancy is retained for mutation rates between 0.001 and 0.1 per cell division. The sexual organism outgrows the asexual organism when the above mutation rates apply. If they compete for finite resources the asexual organism will be extinguished. Variants of the sexual organism with increased redundancy will outgrow those with lower levels of redundancy and the sexual process facilitates the evolution of more complex forms. There is a limit to the extent that complexity can be increased by increasing the size of the genome and in asexual organisms this leads to progressive accumulation of mutations with loss of redundancy and eventual extinction. If complexity is increased by using genes in new combinations, the asexual form can reach a stable equilibrium, although it is associated with some loss of redundancy. The sexual form, by comparison, can survive, with retention of redundancy, even if the mutation rate is above one per generation. The conservation and evolution of redundancy, which is essential for complexity, depends on the sexual process of reproduction.

The elderly and waterborne Cryptosporidium infection: gastroenteritis hospitalizations before and during the 1993 Milwaukee outbreak

We used the Temporal Exposure Response Surfaces modeling technique to examine the association between gastroenteritis-related emergency room visits and hospitalizations in the elderly and drinking water turbidity before and during the 1993 Milwaukee waterborne Cryptosporidium outbreak. Before the outbreak, the rate of such events increased with age in the elderly (p</=0.001), suggesting that the elderly are at an increased risk. During the outbreak, strong associations between turbidity and gastroenteritis-related emergency room visits and hospitalizations occurred at temporal lags of 5-6 days (consistent with the Cryptosporidium incubation period). A pronounced second wave of these illnesses in the elderly peaked at 13 days. This wave represented approximately 40% of all excess cases in the elderly. Our findings suggest that the elderly had an increased risk of severe disease due to Cryptosporidium infection, with a shorter incubation period than has been previously reported in all adults and with a high risk for secondary person-to-person transmission.

Serum dioxin and psychological functioning in U.S. Air Force veterans of the Vietnam War

Using the Minnesota Multiphasic Personality Inventory and the Millon Clinical Multiaxial Inventory, we assessed the psychological functioning of U.S. Air Force veterans exposed to Agent Orange and its contaminant, 2,3,7,8-tetrachlodibenzo-p-dioxin (dioxin), during the Vietnam War. Index subjects were veterans of Operation Ranch Hand (N = 1,109). Comparisons (N = 1,493) were U.S. Air Force veterans not involved with spraying herbicides. We found few consistent psychological abnormalities associated with serum dioxin levels. Ranch Hand veterans with higher dioxin levels showed some difficulties in anxiety, somatization, depression, and a denial of psychological factors. However, those with background levels also showed indications of emotional distress, primarily in emotional numbing and lability; a guarded, suspicious, and withdrawn style of relating to others; and unusual thoughts or behaviors.

The mathematical basis of sexual attraction

Computer programs have been written to study the dynamic interaction in humans between environmental mutagenesis, the genomic load of deleterious mutations and the probability of zygote survival. The human genome is complex and highly redundant and as a consequence deleterious mutations accumulate. The computer programs are based on a model of the human genome in which deleterious mutations interact synergistically causing impaired performance in individual systems and this leads to a positive correlation between the total number of deleterious mutations in the genome and impaired performance across the whole spectrum of biological capability. This includes performance in intellectual tasks, sporting ability, the ability to fight disease and preserve health and the development of a symmetrical physical form. Sexual reproduction distributes deleterious mutations unequally amongst zygotes and the model predicts that zygote survival will correlate negatively with zygote mutational load. The computer simulation shows that rising environmental mutagenesis will lead to a rise in the human genomic mutational load and to decreased zygote survival, although the full effect would take several generations. If this occurred the health of future generations would suffer and methods to monitor environmental mutagenesis are required. The model also shows that a marked rise in environmental mutagenesis would lead to species extinction if mate choice were random, i.e., unrelated to the genomic mutational load. The biological imperfections caused by mutations, however, in health, intelligence and physical symmetry are all, to varying degrees, related to sexual attraction. The model shows that if mates are chosen in response to sexual attraction the species can be maintained in the presence of high environmental mutagenesis. A polygamous pattern in which females mate with a minority of males has the most marked effect in reducing the number of deleterious mutations in the next generation. The model also shows that as environmental mutagenesis falls the number of eligible males would increase and a species would change from a polygamous to a monogamous pattern of mating. These results imply that we are not attracted by good genes, but by a lack of bad genes. Sexual attraction is a force which counteracts genomic degradation.

Environmental health surveillance: indicators for freshwater ecosystems

The relationship between the health of human populations and the state of the ecosystems in which they live is profoundly complex. As most environmental indicators relevant to human health depend on evidence of a direct cause and effect relationship, there are few indicators of the less direct consequences of environmental degradation on human health. Indicators of the direct consequence of contaminants in freshwater ecosystems on human health are highlighted in this paper and candidate indicators for environmental health are provided. Many of the indicators included here are from the State Of the Lakes Ecosystem Conference (SOLEC) program. SOLEC conferences in the past (1994 and 1996) examined the state of various components of the ecosystem through the use of ad hoc indicators, and provided subjective assessments of certain environmental conditions. At SOLEC 98, a comprehensive suite of 80 Great Lakes ecosystem health indicators was presented for review, refinement and acceptance. Candidate indicators for freshwater systems and environmental health presented here are organized following the "Pressure-State-Response" framework and cover the areas of drinking water, recreational water, freshwater food sources, and the availability of freshwater for economic activities.

Environmental health surveillance: indicators for freshwater ecosystems

The relationship between the health of human populations and the state of the ecosystems in which they live is profoundly complex. As most environmental indicators relevant to human health depend on evidence of a direct cause and effect relationship, there are few indicators of the less direct consequences of environmental degradation on human health. Indicators of the direct consequence of contaminants in freshwater ecosystems on human health are highlighted in this paper and candidate indicators for environmental health are provided. Many of the indicators included here are from the State Of the Lakes Ecosystem Conference (SOLEC) program. SOLEC conferences in the past (1994 and 1996) examined the state of various components of the ecosystem through the use of ad hoc indicators, and provided subjective assessments of certain environmental conditions. At SOLEC 98, a comprehensive suite of 80 Great Lakes ecosystem health indicators was presented for review, refinement and acceptance. Candidate indicators for freshwater systems and environmental health presented here are organized following the "Pressure-State-Response" framework and cover the areas of drinking water, recreational water, freshwater food sources, and the availability of freshwater for economic activities.

Airborne particulates and hospital admissions for cardiovascular disease: a quantitative review of the evidence

This is a quantitative review of studies characterizing the relationship between exposure to airborne particulates and hospital admissions for cardiovascular disease. A MEDLINE search and a review of reference lists were conducted to identify time-series studies that considered particles less than 10 microm or 2.5 microm in diameter (PM(10) and PM(2.5), respectively) and their association with day-to-day variation in cardiovascular admissions. The results of these studies were standardized to give estimates of the percentage increase in hospital admissions associated with an increase in ingestion of ambient particles of 10 microg/m3. The results were grouped and compared on the basis of the specific outcomes and exposure measures. When studies that considered the association between PM(10) exposure and specific cardiovascular outcomes were pooled (after exclusion of outliers), a 10-microg/m(3) increase in PM(10) was associated with increases in admission rates of 0.8% (95% confidence interval [CI]: 0.5, 1.2%) for congestive heart failure, 0.7% (95% CI: 0.4, 1.0%) for ischemic heart disease, and 0.2% (95% CI: -0.2, 0.6%) for cerebrovascular accidents. These effects tended to diminish substantially when gaseous co-pollutants were considered. The extent to which these effects are due to fine particles is unclear. The available studies indicate that exposure to airborne particles is associated with hospital admissions for cardiovascular disease; but the magnitude of this effect depends strongly on the specific disease category being considered, the time lag used in the analysis, and the type and amount of co-pollutants. Future studies should include careful consideration of the role of co-pollutants in this association, the interaction of particles with temperature, the impact of particle size on this effect, and the extent to which the observed effect involves short-term "harvesting."

Serum dioxin and cognitive functioning among veterans of Operation Ranch Hand

We used the Halstead-Reitan neuropsychological test battery, the Wechsler adult intelligence scale-revised, the Wechsler memory scale, and the wide range achievement test to assess cognitive functioning among Air Force veterans exposed to Agent Orange and its contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), during the Vietnam war The index subjects were veterans of Operation Ranch Hand (N = 937), the unit responsible for aerial herbicide spraying in Vietnam from 1962 to 1971. A comparison group of other Air Force veterans (N= 1,052), who served in Southeast Asia during the same period but were not involved with spraying herbicides served as referents. Cognitive functioning was assessed in 1982, and dioxin levels were measured in 1987 and 1992. We assigned each Ranch Hand veteran to the background, low, or high dioxin exposure category on the basis of a measurement of dioxin body burden. Although we found no global effect of dioxin exposure on cognitive functioning, we did find that several measures of memory functioning were decreased among veterans with the highest dioxin exposure. These results became more distinct when we restricted the analysis to enlisted personnel, the subgroup with the highest dioxin levels. An analysis based on dioxin quintiles in the combined cohort produced consistent results, with veterans in the fifth quintile exhibiting reduced verbal memory function. Although statistically significant, these differences were relatively small and of uncertain clinical significance.

Linking sight and sound: fMRI evidence of primary auditory cortex activation during visual word recognition

We describe two studies that used repetition priming paradigms to investigate brain activity during the reading of single words. Functional magnetic resonance images were collected during a visual lexical decision task in which nonword stimuli were manipulated with regard to phonological properties and compared to genuine English words. We observed a region in left-hemisphere primary auditory cortex linked to a repetition priming effect. The priming effect activity was observed only for stimuli that sound like known words; moreover, this region was sensitive to strategic task differences. Thus, a brain region involved in the most basic aspects of auditory processing appears to be engaged in reading even when there is no environmental oral or auditory component.

Relation between Kaufman Brief Intelligence Test and WISC-III scores of children with RD

Concurrent validity of the Kaufman Brief Intelligence Test (K-BIT) with the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) was evaluated, as well as the K-BIT's accuracy as a predictor of WISC-III scores, in a sample of young children with reading disabilities. The two measures were administered to 65 children from Atlanta, Boston, and Toronto who ranged from 6-5 to 7-11 years of age at testing. Correlations between the verbal, nonverbal, and composite scales of the K-BIT and WISC-III were .60, .48, and .63, respectively. Mean K-BIT scores ranged from 1.2 to 5.0 points higher than the corresponding WISC-III scores. Standard errors of estimation ranged from 10.0 to 12.3 points. In individual cases, K-BIT scores can underestimate or overestimate WISC-III scores by as much as 25 points. Results suggest caution against using the K-BIT exclusively for placement and diagnostic purposes with young children with reading disabilities if IQ scores are required.

Social problem solving in children with acquired brain injuries

OBJECTIVES

To assess the performance of children with acquired brain injuries (ABIs) on a measure of social problem solving and to examine the relationships between participant characteristics and performance on the Social Knowledge Interview (SKI) and between parent-reported child behavior and performance on the SKI.

DESIGN

Between-group comparisons using correlational analyses, matched pairs t-tests, and analysis of covariance (ANCOVA).

PARTICIPANTS

Thirty-one children 6-12 years old with ABI and 31 control participants, matched on age and sex.

MAIN OUTCOME MEASURE

The SKI, a measure of social problem-solving skills.

RESULTS

Using matched pairs t-tests and ANCOVA, groups were compared on several SKI measures, including the number of unique responses generated for each problem scenario, the quality of those responses, and the ability to select the best response from a set of alternatives. When equated for socioeconomic status (SES), ABI and control participants performed similarly on the SKI; however, a trend for children with ABI to generate more assertive responses was observed. Performance on the SKI was positively correlated with IQ and related to parent-reported adaptive behavior. In children with ABI, performance was also related to primary lesion location and treatment regimen.

CONCLUSIONS

Children with ABI are as capable of judging the appropriateness of behavior and generating response options on an analog measure of social problem solving as were their typically developing peers. However, those individual children with ABI who are more likely to have social problems may be identified by the qualitative aspects of their responses on analog tasks. These findings have implications for the identification of children with social skills deficits following ABI and for the development of effective rehabilitation strategies.

Use of passive surveillance data to study temporal and spatial variation in the incidence of giardiasis and cryptosporidiosis

OBJECTIVE

The goal of this study was to evaluate temporal and spatial variations in the reporting of cases of giardiasis and cryptosporidiosis to a passive surveillance system, and to assess the relationship of those variations to source of drinking water, adjusting for socioeconomic variables.

METHODS

The authors analyzed temporal and spatial patterns for 4,058 cases of giardiasis and 230 cases of cryptosporidiosis reported to the Massachusetts Department of Public Health for 1993-1996. They linked each reported case to a database containing information on source of residential water supply and socioeconomic characteristics and evaluated the association between these factors and reporting rates using regression techniques.

RESULTS

Reports of giardiasis and cryptosporidiosis were highest for the mixed unfiltered drinking water supply category. Reports of giardiasis were associated with income levels. Increases in reporting for both giardiasis and cryptosporidiosis were seen in summer to early fall. During a suspected outbreak of cryptosporidiosis n the city of Worcester in 1995, a significant increase in reported cases was also observed in the Boston metropolitan area. Following the suspected outbreak, weekly giardiasis rates increased slightly in Worcester and the Boston metropolitan area, while reporting of cryptosporidiosis increased dramatically.

CONCLUSIONS

Consistently collected passive surveillance data have the potential to provide valuable information on the temporal variation of disease incidence as well as geographic factors. However, passive surveillance data, particularly in the initial period of surveillance, may be highly sensitive to patterns of diagnosis and reporting and should be interpreted with caution.

Estimation of Markov random field prior parameters using Markov chain Monte Carlo maximum likelihood

Recent developments in statistics now allow maximum likelihood estimators for the parameters of Markov random fields (MRFs) to be constructed. We detail the theory required, and present an algorithm that is easily implemented and practical in terms of computation time. We demonstrate this algorithm on three MRF models--the standard Potts model, an inhomogeneous variation of the Potts model, and a long-range interaction model, better adapted to modeling real-world images. We estimate the parameters from a synthetic and a real image, and then resynthesize the models to demonstrate which features of the image have been captured by the model. Segmentations are computed based on the estimated parameters and conclusions drawn.

Carbon monoxide and hospital admissions for congestive heart failure: evidence of an increased effect at low temperatures

The combined effects of carbon monoxide and low temperature on daily variation in hospital admissions for congestive heart failure (CHF) were examined for a 4-year period in Chicago, Illinois. Medicare hospital admissions for CHF were analyzed as a function of the maximum hourly temperature, maximum hourly levels of carbon monoxide (CO), and other criteria pollutants in Chicago for each day of the 4-year period (1986-1989). The regression analyses for the time series were conducted using single and multipollutant models with interaction terms and adjustments for weather, weekly cycles, seasonal effects, and secular trend. The data were also grouped into three temperature ranges, <40 degrees, 40 degrees-75 degrees, and >75 degrees F, and the relationship between CO and CHF admissions was evaluated for each range. For the 4-year time series, the CO level was positively associated with hospital admissions for CHF in the single pollutant and multipollutant models after adjustment for seasonal effects and weather pattern. The relative risks of hospital admissions for CHF in Chicago associated with the 75th percentile of exposure to CO in the high, medium, and low temperature ranges were 1.02 [95% confidence interval (CI), 0.95-1.10], 1.09 (CI, 1.04-1.14), and 1.15 (CI, 1.09-1.22), respectively. In these data, the effect of CO on hospital admissions for CHF was temperature dependent, with the magnitude of the effect increasing with decreasing temperature. This synergy may help to explain the association between ambient CO and CHF admissions demonstrated in other studies.

Parent assessment of psychological and behavioral functioning following pediatric acquired brain injury

OBJECTIVE

Compare the measured prevalence rate of psychopathology and behavior disorders in 29 children with acquired brain injuries using four parent-report instruments.

METHOD

Two questionnaires, the Child Behavior Checklist (CBCL) and the Personality Inventory for Children (PIC-R) and two interview measures, the Diagnostic Interview for Children and Adolescents (DICA-R) and the Vineland Adaptive Behavior Scales (VABS), were completed following injury or diagnosis.

RESULTS

The DICA-R identified the highest prevalence of anxiety disorders and acting-out behaviors, whereas the CBCL identified the lowest prevalence. Opposite results were found within the domain of attentional problems. Interview measures were more concordant for global psychological impairment than were questionnaires.

DISCUSSION

Discordant findings across measures are discussed in terms of type of disorder, classification model, response format, item characteristics, and scaling.

Did Milwaukee experience waterborne cryptosporidiosis before the large documented outbreak in 1993?

The patterns of incidence and pathways of spread for cryptosporidiosis are poorly understood. In this study, we explored the possibility that drinking water caused significant waterborne cryptosporidiosis in Milwaukee well before the massive documented outbreak in April 1993. We generated time series of daily counts of emergency room visits and hospital admissions for gastroenteritis in Milwaukee using the billing records of the Medical College of Wisconsin for January 1, 1992, through May 3, 1993. The Milwaukee Water Works provided us with data on drinking water turbidity for the same period. The service area of the South Plant experienced a sharp rise in turbidity just before the outbreak. During the outbreak period, gastroenteritis events were most strongly associated with turbidity at a lag of 7 days in children and 8 days in adults. It is reasonable to conclude that these lag times reflect the incubation period of Cryptosporidium. During the 434 days before the outbreak, gastroenteritis events were most strongly associated with turbidity at a lag of 8 days among children and 9 days among adults in the service area of the North Plant, the plant that experienced the highest effluent turbidity during this period. These findings are consistent with the conclusion that waterborne cryptosporidiosis was occurring in Milwaukee for more than a year before the documented outbreak.

Cognitive-behavioral remediation of problem solving deficits in children with acquired brain injury

The inability to problem solve can have a deleterious impact on a student's academic performance and social adjustment. Children with an acquired brain injury (ABI) are at risk for deficits in problem solving skills. This case study and series of multiple baseline experiments examined the effects of a multi-component cognitive-behavioral training program on the remediation of problem solving deficits in five children with ABI. Results indicated that the training program resulted in a substantial decrease in errors on a computerized problem solving task used to monitor problem solving performance during baseline and treatment. In addition, significant improvements were found on two of four standardized measures of problem solving abilities. Finally, students, parents and teaching staff reported a high degree of satisfaction with and generalization of the training program.

Additive impact of in-hospital cardiac arrest on the functioning of children with heart disease

OBJECTIVE

This study examined the impact of a sudden cardiac arrest (CA) on the neurodevelopmental and adaptive functioning of young children with congenital heart disease (CHD).

METHODOLOGY

Sixteen children with CHD who had sustained an in-hospital CA were compared with a medically similar group of children with CHD who had not incurred a CA. The contribution of CA, disease severity, and family socioeconomic status on the prediction of developmental outcome variables was evaluated.

RESULTS

Children in the CA group displayed more impairments in general cognitive, motor, and adaptive behavior functioning as well as greater disease severity as measured by a cumulative medical risk index. With respect to all children in the study, a higher socioeconomic status was related to higher scores on cognitive functioning, lower levels of child maladjustment, and lower levels of stress within the parent-child relationship. Although the occurrence of a CA alone did not contribute to the prediction of outcome measures, a significant interactional effect between CA and cumulative medical risk index was found. Specifically, among children who had incurred a CA, as disease severity increased, decrements in abilities were observed. Few significant correlations between specific CA-related variables (eg, length of CA) and outcome indices were found.

CONCLUSIONS

Results from this study indicate that the impact of cardiac arrest on neuropsychological functioning may be mediated by the child's overall disease severity. These findings have implications for the identification of CA survivors at greatest risk for developmental difficulties.

Childhood asthma surveillance using computerized billing records: a pilot study

OBJECTIVE

This paper describes a pilot project to develop and implement a low-cost system for ongoing surveillance of childhood asthma in Milwaukee County, Wisconsin.

METHODS

The authors organized a planning workshop to solicit information and ideas for an asthma surveillance system, bringing together national experts with Milwaukee professionals and community representatives involved in the prevention and treatment of asthma. Based on recommendations from the workshop, a pilot surveillance project was implemented in Milwaukee County using records of emergency room visits and hospital admissions for asthma abstracted from the computerized billing records of the Children's Hospital of Wisconsin (CHW), retrospectively for 1993 and prospectively for 1994. Retrospective data were also sought from the other hospital emergency departments in Milwaukee County to evaluate the representativeness of the CHW data. Surveillance data were used to evaluate utilization of care by patient subgroups and to describe temporal patterns in emergency room visits.

RESULTS

Of the emergency department visits for asthma in Milwaukee County in 1993, CHW accounted for 94% among infants less than 1 year of age, 89% among children ages 1 through 5 years, and only 59% among children between the ages of 6 and 18 years. In 1994, the 7% of asthmatic children with repeat hospital admissions accounted for 38% of all hospital admissions for asthma and the 20% with repeat emergency department visits accounted for 50% of all emergency visits. Emergency visits for asthma showed clear seasonality, with a peak in the fall and a smaller peak in the spring.

CONCLUSIONS

Computerized medical billing data provide an opportunity for asthma surveillance at a relatively low cost. The data obtained are useful for tracking trends in exacerbations of asthma and the use of medical services for asthma care and should prove valuable in targeting interventions.

Breast-conserving therapy vs mastectomy in early-stage breast cancer: a meta-analysis of 10-year survival

BACKGROUND

The randomized trials comparing breast-conserving therapy (BCT), i.e., surgery and radiation to the breast, with mastectomy in early-stage breast cancer use a variety of protocols. Meta-analysis may assist in understanding the impact of these differences on survival.

PURPOSE

To evaluate the possible variations of the relative efficacy of BCT and mastectomy in terms of overall survival according to tumor size, nodal status, and use of adjuvant radiation therapy.

METHODS

The most recent published results and, where available, updated patient-level data from randomized controlled trials of BCT and mastectomy for early-stage breast cancer were combined in a meta-analysis using a random effects model. Pooled survival rates and odds ratios were generated according to subgroups of nodal status and tumor size. Five- and 10-year odds ratios were also determined according to adjuvant radiation protocol.

RESULTS

The pooled odds ratio comparing 10-year survival for BCT and mastectomy was 0.91. The odds ratios comparing the two treatment regimens were not significant after grouping according to tumor size and nodal status. When more than 50% of node-positive patients in both the mastectomy and BCT arms received adjuvant radiation, both arms had similar survival rates. When less than 50% of node-positive patients in both arms received adjuvant nodal radiation, the odds ratio was 0.69, and patients receiving BCT had a survival advantage.

CONCLUSIONS

Patients allocated to BCT have survival rates at least as high as patients allocated to mastectomy. When all protocols were combined, nodal status and tumor size did not significantly alter the relative survival rates. However, under some conditions, particularly for node-positive patients, BCT may confer a relative survival advantage over mastectomy. In particular, mastectomy without adjuvant radiation appears to be inferior to BCT for node-positive patients.

NES test performance in a large US Army veteran sample: relationships with both demographic factors and traditional neuropsychological measures

A large sample of Vietnam-era US Army veterans completed a set of 16 neuropsychological tests, including six computer-based tests from the Neurobehavioral Evaluation System (NES), during medical examinations supervised by the US Centers for Disease Control (CDC). Data for 881 participants of the Agent Orange Validation Study (AOV) and Vietnam Experience Study (VES) were available for analysis from public access data tapes provided by CDC. Information was available for several potential covariates from demographic questionnaires, a medical examination, and a medical history. Explorator, principal components factor analysis of 16 test variables yielded four factors, including one on which most of the NES tests loaded. The single best predictor of most neuropsychological performance variables was an index of general intellectual level as measured at entry into the Army almost 20 years before the neuropsychological examinations. Alcohol drinking variables were not related to neuropsychological performance. Several measures of general intelligence were compared for use as covariates of neuropsychological test performance. All were superior to years of education in statistically controlling for general intellectual level.

Localization of disease clusters using regional measures of spatial autocorrelation

Maps of disease rates are often used to identify regions with elevated disease rates. The goal of this study was to develop and evaluate a regional measure of spatial autocorrelation for localization of these clusters. A regional spatial autocorrelation coefficient (RSAC) was defined and a theoretical mean and standard deviation was derived for its probability distribution. The RSAC was used to identify spatial units that belong to disease clusters. The sensitivity and specificity of the RSAC method in detecting simulated disease clusters was evaluated. For comparison the simulated data were also used to evaluate methods employed by the National Cancer Institute (NCI) for mapping cancer mortality in the United States. The distribution of pancreatic cancer among the elderly white male population in the United States was also evaluated. Within a simulated disease cluster with a relative risk of 2, the RSAC method detected between 75 per cent and 91 per cent of the units depending on the size of the spatial unit used for the analysis. The corresponding sensitivities of the NCI method ranged from 9 per cent to 68 per cent. The RSAC map of pancreatic cancer demonstrated an area of positive clustering (clustering of high rates) in the south central United States. The RSAC method localized disease clusters with greater sensitivity than the NCI method, particularly when geographic units were small. The RSAC method is an effective tool for the identification of regional disease clusters.

Temporal variation in drinking water turbidity and diagnosed gastroenteritis in Milwaukee

Daily counts of diagnosed gastroenteritis (gastrointestinal events) in Milwaukee County, Wisconsin, from January 1992 through April 1993 were compared with reported daily turbidity from the two drinking water treatment plants serving the county. Turbidity in both plants was associated with an increased number of gastrointestinal events even after exclusion of a major documented outbreak of cryptosporidiosis. During the 434-day period prior to the outbreak, an increase in turbidity of 0.5 nephelometric turbidity units at one of the plants was associated with relative risks for gastrointestinal events of 2.35 among children (95% confidence interval [CI] = 1.34, 4.12) and 1.17 among adults (95% CI = 0.91, 1.52).

Fast probabilistic self-structuring of generalized single-layer networks

An algorithm is presented for determining the subset of the basis functions of a generalized single-layer network (GSLN) needed to solve the classification problem defined by the training data. A Markov chain Monte Carlo sampling technique is used to traverse the space of models having a low sum squared error (SSE). The frequency of a term's inclusion is an indication of its importance to the classifier. Fast, iterative updates can be used for the matrix calculations needed. Theoretical results for the required length of the chain needed to obtain good discrimination between functions fitting the data and those modeling the added noise are given, and these are confirmed by experiment.

Family and illness predictors of outcome in pediatric brain tumors

Investigated the prediction of cognitive and behavioral outcomes in 63 children with heterogenous brain tumors. Hierarchical multiple regression analyses were used to determine how family-related variables added to the prediction of children's outcome over and above illness measures. The best predictors of children's behavior problems and adaptive behavior were family and demographic variables, whereas the best predictors of achievement were illness and demographic variables. A combination of family and illness variables, however, was the best predictor of intellectual functioning. In addition to identifying specific predictors of cognitive and behavioral outcome in children with brain tumors, these results lend initial support for the inclusion of contextual factors such as family stress, maternal coping, number of parents in the home, and family SES measures in studies of how disease factors affect outcomes in pediatric brain tumor patients.

Drinking water and cancer

Any and all chemicals generated by human activity can and will find their way into water supplies. The types and quantities of carcinogens present in drinking water at the point of consumption will differ depending on whether they result from contamination of the source water, arise as a consequence of treatment processes, or enter as the water is conveyed to the user. Source-water contaminants of concern include arsenic, asbestos, radon, agricultural chemicals, and hazardous waste. Of these, the strongest evidence for a cancer risk involves arsenic, which is linked to cancers of the liver, lung, bladder, and kidney. The use of chlorine for water treatment to reduce the risk of infectious disease may account for a substantial portion of the cancer risk associated with drinking water. The by-products of chlorination are associated with increased risk of bladder and rectal cancer, possibly accounting for 5000 cases of bladder cancer and 8000 cases of rectal cancer per year in the United States. Fluoridation of water has received great scrutiny but appears to pose little or no cancer risk. Further research is needed to identify and quantify risks posed by contaminants from drinking-water distribution pipes, linings, joints, and fixtures and by biologically active micropollutants, such as microbial agents. We need more cost-effective methods for monitoring drinking-water quality and further research on interventions to minimize cancer risks from drinking water.

Ambient air pollution and hospitalization for congestive heart failure among elderly people in seven large US cities

OBJECTIVES

Preexisting data sets were used to investigate the association between hospital admissions for congestive heart failure and air pollutants.

METHODS

Medicare hospital admissions data, ambient air pollution monitoring data, and meteorological data were used to create daily values of hospital admissions for congestive heart failure, maximum hourly temperature, and maximum hourly levels of carbon monoxide, nitrogen dioxide, sulfur dioxide, and ozone. Data were compiled for each of seven cities (Chicago, Detroit, Houston, Los Angeles, Milwaukee, New York, and Philadelphia) for 1986 through 1989. Single-pollutant and multipollutant models with adjustments for temperature, seasonal effects, and weekly cycles were used in conducting negative binomial regression analyses.

RESULTS

Ambient carbon monoxide levels were positively associated with hospital admissions for congestive heart failure in the single-pollutant and multipollutant models for each of the seven cities. The relative risk of hospital admission for congestive heart failure associated with an increase of 10 ppm in carbon monoxide ranged from 1.10 in New York to 1.37 in Los Angeles.

CONCLUSIONS

Hospital admissions for congestive heart failure exhibited a consistent association with daily variations in ambient carbon monoxide. This association was independent of season, temperature, and other major gaseous pollutants.

Detection of missing data in image sequences

Bright and dark flashes are typical artifacts in degraded motion picture material. The distortion is referred to as "dirt and sparkle" in the motion picture industry. This is caused either by dirt becoming attached to the frames of the film, or by the film material being abraded. The visual result is random patches of the frames having grey level values totally unrelated to the initial information at those sites. To restore the film without causing distortion to areas of the frames that are not affected, the locations of the blotches must be identified. Heuristic and model-based methods for the detection of these missing data regions are presented in this paper, and their action on simulated and real sequences is compared.

Interpolation of missing data in image sequences

This paper presents a number of model based interpolation schemes tailored to the problem of interpolating missing regions in image sequences. These missing regions may be of arbitrary size and of random, but known, location. This problem occurs regularly with archived film material. The film is abraded or obscured in patches, giving rise to bright and dark flashes, known as "dirt and sparkle" in the motion picture industry. Both 3-D autoregressive models and 3-D Markov random fields are considered in the formulation of the different reconstruction processes. The models act along motion directions estimated using a multiresolution block matching scheme. It is possible to address this sort of impulsive noise suppression problem with median filters, and comparisons with earlier work using multilevel median filters are performed. These comparisons demonstrate the higher reconstruction fidelity of the new interpolators.

Meta-analysis in cancer epidemiology

Meta-analysis has seen increasing use as a tool in epidemiology over the past five years. Although this method is relatively well accepted for use in clinical trials, its use has proved somewhat more controversial in epidemiology. If meta-analysis is viewed as an evolutionary improvement over the review article, it may become more widely acceptable. Meta-analysis should incorporate the concern for study quality and differences in study design seen in classic review articles with the concern for rigor, objectivity, and quantitative precision characteristic of meta-analysis. Available tools for consideration of differences among studies are described with several examples from the literature. The extent to which various methods are used in published meta-analyses is described. Methods for assessing publication bias, and tools for combining dose-response data, are discussed also. Evaluation of risk factors and protective factors for cancer must be based on the weight of the evidence. Tools such as meta-analysis are essential if we are to interpret the vast number of completed studies in cancer epidemiology.

Geographic variability in hospital admission rates for respiratory disease among the elderly in the United States

BACKGROUND

The elderly represent a susceptible subpopulation that experiences disproportionate levels of morbidity and mortality from respiratory disease. As a consequence, they are frequently hospitalized for these conditions. Evaluating the geographic distributions of these hospital admissions can provide useful insights concerning patterns in incidence and medical care for respiratory diseases.

METHODS

All hospital admissions for pneumonia, acute respiratory infections, asthma, and chronic obstructive pulmonary disease from the United States for a 6-year period (1984 through 1989) were identified using Medicare admissions records. Age-, race-, and sex-standardized annual admission rates were calculated for each county and spatial clustering of disease specific rates was evaluated using Moran's I statistic. Ecologic analyses were conducted using multiple regression procedures with county-specific measures of average annual temperature, average income, household crowding, median educational level, population density, physicians per capita, and hospital beds per capita together with surrogate measures of cigarette consumption and occupational exposures as predictor variables.

RESULTS

Hospital admission rates in the elderly for all four categories of respiratory disease showed marked regional elevations (p < 0.0001), particularly in the southeast and the northern plains states. Low median education level, low per capita income, and household crowding were all associated with elevated hospital admission rates. Surrogate measures of cigarette consumption were strongly associated with hospital admissions in all four disease groups. Hospital beds per capita demonstrated positive associations with hospital admissions, but the number of physicians per capita exhibited consistent inverse relationships with hospital admissions.

CONCLUSIONS

Hospital admission rates for respiratory diseases among the elderly show marked geographic variation and are associated with regional indicators of socioeconomic status, availability of medical resources, occupational lung disease rates, and smoking.

Predicting injury risk in adolescent football players: the importance of psychological variables

Explored the relationship of anger/aggression, attention, and stressful life events to injury while addressing the methodological limitations of prior studies. An additional objective was to determine whether the relationship of stressful life events to injury is mediated either by anger (directed either inward or outward) or by impaired attention, either vigilant (broad, external) or focused (narrow, internal). At the beginning of summer practice, 120 first-string high school football players completed measures of anger (Framingham Anger Scale), vigilant attention (Symbol Digit Modalities test), focused attention (Pursuit subtest, MacQuarrie Test of Mechanical Ability), and stressful life events (abbreviated form of the Social Readjustment Rating Scale as modified for use with adolescents by Coddington, 1972). Players were then followed through one season to identify those injured. Logistic regression indicated that high anger directed outward (p < .05) and low focused attention (p < .01) increased injury risk, while stressful life events and vigilant attention interacted. Injury risk was elevated when recent stress was present (p < .05), and increased as vigilance decreased, suggesting that stressful life events elevate injury risk by reducing vigilance.

Aggregation of existing geographic regions to diminish spurious variability of disease rates

The availability of large data sets together with the growth in power and storage capabilities of computers have made the analysis of the spatial distribution of disease rates an increasingly important tool in public health research. Use of existing geographic divisions or groupings tends to result either in unstable estimates of disease rates if the corresponding populations are small or in loss of spatial resolution if the areas are unnecessarily large. This paper describes a computer algorithm for combining existing geographic areas into regions with populations large enough to diminish spurious variability in disease rates while limiting the loss in resolution. The method is demonstrated using Medicare hospital admissions data for pneumonia and central nervous system cancer. Disease rates were calculated for both predefined regions and those generated by the algorithm and their frequency distributions were compared. The algorithm produces more stable rates over a variety of diseases and provides substantially more flexibility than the use of predefined aggregations.

Assessment of hand preference in two language-trained chimpanzees (Pan troglodytes): a multimethod analysis

The nonhuman primate literature concludes that monkeys and apes do not exhibit handedness preferences at the population level. This discrepancy between human and nonhuman primate findings may be due to differences in the methods of assessment of handedness, lack of reliability between various measures of handedness, and a paucity of studies involving great apes. This paper presents the results of extensive hand preference studies with two language-trained chimpanzees (Pan troglodytes). Both naturalistic and experimental paradigms are described. In particular, various methodologic factors involved in handedness assessment, including the use of a hand preference measure previously used with human subjects were examined. Both chimpanzees exhibited a right-hand preference for fine motor tasks requiring manual dexterity.

Perception of human chimeric faces by chimpanzees: evidence for a right hemisphere advantage

The aim of this study was to investigate hemispheric advantages in the processing of human chimeric faces by chimpanzees using a free-vision task developed by Levy, Heller, Banich, and Burton (1983a). Subjects were taught a visual discrimination in which they were to select the human face that appeared "happiest" when paired with its neutral counterpart. After reaching criterion, chimeric faces were substituted as test trials, and the face the subjects selected was recorded. On 62% of the trials, three chimpanzee subjects selected the face in which the smiling half fell in the left hemispatial field. Familiarity factors appear to have accounted for some of the observed findings. We believe this is the first evidence for hemispheric advantages in the perception of human faces by great apes.

Neuropsychological, academic, and adaptive functioning in children who survive in-hospital cardiac arrest and resuscitation

Children suffering cardiac arrest (CA) are not uncommon in certain pediatric populations. Due to the increasing survival rates of child CA patients, there is a growing interest in, and concern for, their long-term intellectual, academic, emotional, and adaptive functioning. This article describes the possible neurologic sequelae of CA in children and presents standardized assessment results on 25 children, 2 to 15 years of age, who survived a CA while in the hospital. A majority of these children exhibited low-average to deficient levels of performance on neuropsychologic, achievement, and adaptive behavior measures. Duration of cardiac arrest and a medical risk score were significantly correlated with decreased functioning in child CA patients. Children who suffer a cardiac arrest are at high risk for academic struggles, and many may need special education services.

Handedness distribution in a nonspeaking population with mental retardation

Fifty nonspeaking or minimally speaking subjects with moderate, severe, or profound mental retardation underwent evaluation of handedness. Results confirmed previously reported increased prevalence of non-right handedness and the occurrence of a large subtype of ambiguous handedness. Results suggest that incidence of atypical hand preference is not closely linked to level of cognitive impairment, especially as represented by significant speech-language impairment in this population, as has been previously hypothesized. Atypical handedness of persons with mental retardation probably depends on language organization, and there is little support for the view that such subtypes represent bilateral hemispheric damage.

Assessment of the relationship of cerebral hemisphere arousal asymmetry to perceptual asymmetry

This study examined the hypothesis that characteristic individual differences in cerebral hemisphere arousal asymmetry are related to individual differences in perceptual asymmetry observed in verbally based visual half-field tasks. The study used electrophysiological measures of arousal asymmetry rather than behaviorally derived measures (Levy, Heller, Banich, & Burton, 1983). Measures of alpha asymmetry were obtained from 20 right-handed males during a baseline relaxation condition and during a visual half-field version of the lexical decision task. Reaction time measures of perceptual asymmetry were obtained during this task. The results indicated that a basal arousal asymmetry measured at the temporal recording location during the baseline condition was significantly related to individual perceptual asymmetry during the subsequent lexical decision task. This basal arousal asymmetry was relatively stable across different task conditions. A task-related arousal asymmetry measured at the parietal location during the lexical decision task also made a significant contribution in predicting individual perceptual asymmetry. These two measures of individual arousal asymmetry were able to predict 50% of the variance in perceptual asymmetry. The implications of the results for explaining more wide-ranging individual differences in behavioral style and personality are discussed.

Long-term weight fluctuation and non-insulin-dependent diabetes mellitus in white women

The association of long-term weight fluctuation with non-insulin-dependent diabetes mellitus (NIDDM) was investigated for a population of 8232 white female members of the Taking Off Pounds Sensibly (TOPS) weight-awareness program, between the ages of 40 and 50 years. An index of weight fluctuation was developed using current weight, weight at the time maximum height was reached, and recalled maximum and minimum weights for the third and fourth decades for each member of the study population. A logistic regression of diabetes prevalence as a function of weight fluctuation, waist-hip ratio, relative weight, and family history index showed standardized odds ratios of 1.10, 1.22, 1.19, and 1.06, respectively. The results suggest that the magnitude of long-term weight fluctuation is associated with the development of NIDDM.

Chlorination, chlorination by-products, and cancer: a meta-analysis

OBJECTIVES

Individual epidemiological investigations into the association between chlorination by-products in drinking water and cancer have been suggestive but inconclusive. Enough studies exist to provide the basis for a meaningful meta-analysis.

METHODS

An extensive literature search was performed to identify pertinent case-control studies and cohort studies. Consumption of chlorinated water, surface water, or water with high levels of chloroform was used as a surrogate for exposure to chlorination by-products. Relative risk estimates were abstracted from the individual studies and pooled.

RESULTS

A simple meta-analysis of all cancer sites yielded a relative risk estimate for exposure to chlorination by-products of 1.15 (95% CI: 1.09, 1.20). Pooled relative risk estimates for organ-specific neoplasms were 1.21 (95% CI: 1.09, 1.34) for bladder cancer and 1.38 (95% CI: 1.01, 1.87) for rectal cancer. When studies that adjusted for potential confounders were pooled separately, estimates of relative risks did not change substantially.

CONCLUSIONS

The results of this meta-analysis suggest a positive association between consumption of chlorination by-products in drinking water and bladder and rectal cancer in humans.