IQ Data Research Articles

The Scarr-Rowe Interaction in Complete Seven-Year WISC Data from the Louisville Twin Study: Preliminary Report

We examine updated Wechsler IQ data in 7-year old twins from the Louisville Twin Study for evidence of an interaction between the heritability of IQ and socioeconomic status. Data records that had never been entered were recovered, allowing us to increase previously reported sample sizes by more than 20%. Twin families were assigned socioeconomic status scores using a Hollingshead index based on parental education and occupation. A structural equation model in which genetic and environmental variances were modeled as squared linear functions of SES provided ambiguous replication of earlier findings from the National Collaborative Perinatal Project: relations between SES and heritability for performance and full scale IQ were in the same direction as the previous report, but at p < 0.07. As was the case in Turkheimer et al. (Psychol Sci 14(6):623-628, 2003), no interaction was found for VIQ. These results cannot yet be taken as a definitive replication of Turkheimer et al. (Psychol Sci 14(6):623-628, 2003). Many more measurement occasions, subtests and environmental moderators remain to be analyzed.

Photonic circuit for high order USB and LSB separation for remote heterodyning: analysis and simulation

A novel photonic integrated circuit is proposed that, using an RF source, generates at its output ports the same magnitude but opposite sign high order single optical side bands of a suppressed optical carrier. A single stage parallel Mach-Zehnder Modulator (MZM) and a two-stage series parallel MZM architecture are described and their relative merits discussed. A transfer matrix method is used to describe the operation of the circuits. The theoretical analysis is validated by computer simulation. As an illustration of a prospective application, it is shown how the circuit may be used as a key element of an optical transmission system to transport radio signals over fibre for wireless access; generating remotely a mm-wave carrier modulated by digital IQ data. A detailed calculation of symbol error rate is presented to characterise the system performance. The circuit may be fabricated in any integration platform offering a suitable phase modulator circuit element such as LiNbO(3), Silicon, and III-V or hybrid technology.

Intellectual disability and cognitive ability in Darier disease: Swedish nation-wide study.

Darier disease is an autosomal dominant skin disorder caused by mutations in the ATP2A2 gene. Anecdotal reports suggest a relationship between Darier disease and intellectual disabilities, but these reports are based on small clinical samples and limited by absence of control populations. To examine the risk of intellectual disability and subclinical impairments in cognitive ability in Darier disease. We conducted a matched cohort study based on Swedish Population-, Patient- and Conscript Registers. The risk of being diagnosed with intellectual disability was estimated in 770 individuals with Darier disease, compared with matched comparison individuals without Darier disease. Associations were examined with risk ratios from conditional logistic regressions. In addition, we analysed test-based cognitive ability data (i.e. IQ data) from the Swedish conscript examination, for a subset of patients without diagnosed intellectual disability. Individuals with Darier disease had a sixfold increased risk of being diagnosed with intellectual disability (risk ratio 6.2, 95% confidence interval 3.1-12.4). For conscripted individuals with Darier disease but no diagnosed intellectual disability, mean cognitive ability scores were about half a standard deviation lower than for comparison subjects. Darier disease is associated with intellectual disability and subclinical impairments in cognitive ability. The Darier-causing mutations merit further attention in molecular genetic research on intellectual disability and cognitive ability.

Do Smarter Auditors Have More Important Clients? Archival Evidence Based on Unique IQ Data on Swedish Auditors

This study examines the role of an individual auditor’s cognitive ability in delivering high-quality audits and in creating value for clients. Our results from analyzing data from Sweden show that audit partners’ IQ scores obtained from psychological tests are positively related to both audit reporting accuracy and the financial reporting quality of their client firms. We moreover find that an audit partner’s IQ is associated with the audit fee premiums paid both for audit and consultancy services indicating that clients are willing to pay a premium for services of more capable audit partners. Combined, our results show that although audit services are standardized through various control mechanisms and audits are conducted by teams rather than by individual auditors, cognitive ability of audit partners responsible for the audit is still important in delivering high-quality audit services.

Using linked educational attainment data to reduce bias due to missing outcome data in estimates of the association between the duration of breastfeeding and IQ at 15 years.

Background: Most epidemiological studies have missing information, leading to reduced power and potential bias. Estimates of exposure-outcome associations will generally be biased if the outcome variable is missing not at random (MNAR). Linkage to administrative data containing a proxy for the missing study outcome allows assessment of whether this outcome is MNAR and the evaluation of bias. We examined this in relation to the association between infant breastfeeding and IQ at 15 years, where a proxy for IQ was available through linkage to school attainment data.Methods: Subjects were those who enrolled in the Avon Longitudinal Study of Parents and Children in 1990–91 (n = 13 795), of whom 5023 had IQ measured at age 15. For those with missing IQ, 7030 (79%) had information on educational attainment at age 16 obtained through linkage to the National Pupil Database. The association between duration of breastfeeding and IQ was estimated using a complete case analysis, multiple imputation and inverse probability-of-missingness weighting; these estimates were then compared with those derived from analyses informed by the linkage.Results: IQ at 15 was MNAR—individuals with higher attainment were less likely to have missing IQ data, even after adjusting for socio-demographic factors. All the approaches underestimated the association between breastfeeding and IQ compared with analyses informed by linkage.Conclusions: Linkage to administrative data containing a proxy for the outcome variable allows the MNAR assumption to be tested and more efficient analyses to be performed. Under certain circumstances, this may produce unbiased results.

Predicting and retrodicting intelligence between childhood and old age in the 6-Day Sample of the Scottish Mental Survey 1947

In studies of cognitive ageing it is useful and important to know how stable are the individual differences in cognitive ability from childhood to older age, and also to be able to estimate (retrodict) prior cognitive ability differences from those in older age. Here we contribute to these aims with new data from a follow-up study of the 6-Day Sample of the Scottish Mental Survey of 1947 (original N=1208). The sample had cognitive, educational, social, and occupational data collected almost annually from age 11 to 27years. Whereas previous long-term follow-up studies of the Scottish mental surveys are based upon group-administered cognitive tests at a mean age of 11years, the present sample each had an individually-administered revised Binet test. We traced them for vital status in older age, and some agreed to take several mental tests at age 77years (N=131). The National Adult Reading Test at age 77 correlated .72 with the Terman–Merrill revision of the Binet Test at age 11. Adding the Moray House Test No. 12 score from age 11 and educational information took the multiple R to .81 between youth and older age. The equivalent multiple R for fluid general intelligence was .57. When the NART from age 77 was the independent variable (retrodictor) along with educational attainment, the multiple R with the Terman–Merrill IQ at age 11 was .75. No previous studies of the stability of intelligence from childhood to old age, or of the power of the NART to retrodict prior intelligence, have had individually-administered IQ data from youth. About two-thirds, at least, of the variation in verbal ability in old age can be captured by cognitive and educational information from youth. Non-verbal ability is less well predicted. A short test of pronunciation—the NART—and brief educational information can capture well over half of the variation in IQ scores obtained 66years earlier.

Defrauding Cyril Burt: A reanalysis of the social mobility data

In the last comprehensive review by Mackintosh et al. Cyril Burt, Fraud or Framed? (London: Oxford University Press, 1995) of the fraud charges posthumously leveled against the once eminent psychologist Sir Cyril Burt, Mackintosh and Mascie-Taylor asserted that statistical anomalies they detected in his social mobility data of 1961 provided crucial evidence of guilt. The anomalies included apparent departures from normality in some parts of the data, incommensurate cell totals, and suspicious uniformity within IQ bands across fathers and sons. It is shown here that the departures from normality were a natural consequence of unavoidable rounding when inverting the cumulative normal distribution to construct the class IQ bands used in the tables. Elementary procedures are given, known since at least the 1930s, which could have been used by Burt to simultaneously preserve both the normality of his IQ data and the desired population proportions of occupational classes. Other anomalies first noticed by the statistician Donald Rubin are explainable as artifacts produced by fixing marginal totals in the presence of rounding to IQ scores, then using the same weighting procedures to conform to margins. The grounds given by Mackintosh and Mascie-Taylor for finding fraud in Burt's social mobility data are therefore dismissed.

Preschool television programmes: Analysis using SmartSound IQ data logging

As professionals working with children with severe-to-profound hearing impairment, we understand the difficult task these children have ahead of them to learn spoken language to competent levels. T...

A low‐power, high‐gain, and low‐noise 5–6 GHz CMOS low‐noise amplifier with excellent reverse isolation for IEEE 802.11 n/ac WLAN applications

ABSTRACTA low power, high gain, and low‐noise figure (NF) 5–6 GHz low‐noise amplifier (LNA) with excellent reverse isolation in a cost effective 0.18 μm CMOS technology is reported. To achieve sufficient power gain (S21) and reverse isolation (S12), the LNA comprises an inductive source‐degeneration cascode stage followed by a cascode stage. The LNA consumes 7.99 mW, achieving high S21 of 19 ± 1.5 dB for frequencies of 5.1–6.2 GHz and excellent S12 of −67.9 to −73.3 dB for frequencies of 5–6 GHz. In addition, the LNA achieves minimum NF of 2.8 dB at 5.5 GHz and NF of 2.91 ± 0.11 dB for frequencies of 5–6 GHz, one of the best NF results ever reported for a 5‐GHz‐band CMOS LNA. To verify the 5‐GHz LNA, a test IEEE 802.11 wireless local area network (WLAN) transceiver based on the LNA is also designed and implemented. The measured results show that for the 24 channels in 5‐GHz band, the average sensitivity is −77 and 3 dBm better than that (−74 dBm) of the conventional one. A conventional one means the 802.11 WLAN controller in this work is replaced by a commercial RTL8812AR‐VN WLAN controller. In addition, the average error vector magnitude of received IQ data is −32 dB (or 2.5%), 2.5 dB (or 0.8%) better than that (−29.5 dB [or 3.3%]) of the conventional one. The impressive results from this work indicate the high potential of the proposed LNA in 5‐GHz WLAN applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:296–304, 2015

Occupational complexity and lifetime cognitive abilities

Objective:To examine associations between complexity of main lifetime occupation and cognitive performance in later life.Methods:Occupational complexity ratings for data, people, and things were collected from the Dictionary of Occupational Titles for 1,066 individuals (men = 534, women = 532) in the Lothian Birth Cohort 1936. IQ data were available from mean age 11 years. Cognitive ability data across the domains of general ability, processing speed, and memory were available at mean age 70 years.Results:General linear model analyses indicated that complexity of work with people and data were associated with better cognitive performance at age 70, after including age 11 IQ, years of education, and social deprivation.Conclusions:The current findings are supportive of the differential preservation hypotheses that more stimulating environments preserve cognitive ability in later life, although the continued effects into old age are still debated. Studies that have early-life cognitive ability measures are rare, and the current study offers interesting prospects for future research that may further the understanding of successful aging.

Aging trajectories of fluid intelligence in late life: The influence of age, practice and childhood IQ on Raven's Progressive Matrices

BackgroundExamining the trajectory of cognitive abilities in late life is difficult because of the long time required for significant change to occur and the confounding influences of baseline ability, cohort, dropout and practice. PurposeThe aim is to describe cognitive trajectories in late life by estimating the influence of age and practice and by accounting for the potential confounding attributable to ‘Flynn’ and ‘Mathew’ effects. MethodsWe examine repeated measures of fluid intelligence (IQ) in 751 volunteers' ages 62 through 83years sampled from the Aberdeen birth cohorts of 1921 and 1936 for whom archived childhood IQ data provided a rare insight into early life ability. Aging trajectories in fluid intelligence were estimated using Raven's Standardized Progressive Matrices (RPM). Data were analyzed using linear mixed models. ResultsWe estimate that on average RPM decreases annually by over one-half point (age effect). There is also an initial increase of about two points from the first to second test occasion that the test is taken and this may be attributed to practice. Comparisons between birth cohorts suggest that the ‘Flynn’ effect influences our data and that its size was significantly larger in late life. We found no evidence of the ‘Mathew’ effect in late life. ConclusionsCognitive trajectory of fluid ability in late life is a mixture of practice and decline. The influence of practice appears to be greatest after the first repeat testing. Modeling late life decline in this way will enable intervention studies to be performed in normal and prodromal dementia populations more efficiently.

Behavioral characteristics and cognitive development among school age children born to women with epilepsy

Introduction:Greater risks of congenital malformation as well as cognitive and behavioral development in later childhood occur as a result of in utero exposure to antiepileptic drugs (AEDs). We examined the effects of AEDs on behavioral characteristics and cognitive development among school age children born to women with epilepsy.Methods:Children aged 6–15 years and born to women with epilepsy were enrolled in the study. Information was collected on the women’s demographics and the details of their usage/non-usage of AEDs during pregnancy. The Wechsler Intelligence Scale for the Children-Revised (WICS-R) test was administered to the children. The Alexander IQ test and the Conner Parent Rating Scale (CPRS) were administered to the mothers. Comparisons were made between children who had been exposed and not exposed to AEDs in utero and if exposed, according to exposure to AED monotherapy or polytherapy. The mother’s education level and IQ score and data from the same parent’s siblings were evaluated with respect to consanguinity.Results:Forty-one children born to 28 women with epilepsy were enrolled. Seven mothers had multiple pregnancies. Twenty-three pregnancies (56%) were exposed to monotherapy and five (12·1%) to polytherapy. The remaining 13 (31·7%) were not exposed to AEDs. Maternal education level was a significant major factor in child IQ development (P < 0·05). The performance IQ-coding scale results were lower in children exposed to polytherapy than in children exposed to monotherapy in utero (P < 0·05). Although it is difficult to assert with confidence, the sibling assessment indicated a negative effect of valproate on IQ.Conclusion:It is important that the AED dosage be reduced to a minimum to maintain seizure control for healthy cognitive and behavioral development of a child.

The Flynn Effect in Families: Studies of Register Data on Norwegian Military Conscripts and Their Families

In the present paper published data and new analyses are presented and discussed in order to demonstrate the power of family data (siblings and parents to military conscripts with IQ data) in the study of the Flynn effect (FE). In particular, it is shown how studies of the mean intelligence changes in sibships of different sizes and changing proportions of sibship sizes can enhance our understanding how these factors may influence FE. Some new analyses of correlations between intelligence and sibship sizes illustrate how family data can be used to investigate changes in the correlation pattern across generations. It is shown that comparison of the secular trends in the general population and in sibling pairs can be a powerful method in the exploration of the relative influence of between-families and within-families factors in the FE. Surprising connections between the birth order effect on intelligence and the FE are demonstrated.

Cortical Thickness Maturation and Duration of Music Training: Health-Promoting Activities Shape Brain Development

To assess the extent to which playing a musical instrument is associated with cortical thickness development among healthy youths. Participants were part of the National Institutes of Health (NIH) Magnetic Resonance Imaging (MRI) Study of Normal Brain Development. This study followed a longitudinal design such that participants underwent MRI scanning and behavioral testing on up to 3 separate visits, occurring at 2-year intervals. MRI, IQ, and music training data were available for 232 youths (334 scans), ranging from 6 to 18 years of age. Cortical thickness was regressed against the number of years that each youth had played a musical instrument. Next, thickness was regressed against an "Age× Years of Playing" interaction term. Age, gender, total brain volume, and scanner were controlled for in analyses. Participant ID was entered as a random effect to account for within-person dependence. False discovery rate correction was applied (p≤ .05). There was no association between thickness and years playing a musical instrument. The "Age× Years of Playing" interaction was associated with thickness in motor, premotor, and supplementary motor cortices, as well as prefrontal and parietal cortices. Follow-up analysis revealed thatmusic training was associated with an increased rate of thickness maturation. Results were largely unchanged when IQ and handedness were included as covariates. Playing a musical instrument was associated with more rapid cortical thickness maturation within areas implicated in motor planning and coordination, visuospatial ability, and emotion and impulse regulation. However, given the quasi-experimental nature of this study, we cannot ruleout theinfluence of confounding variables.

B-47 * The Impact of Epilepsy on Intellectual, Executive, and Behavioral Functioning in Pediatric Stroke

Objective: Children with a history of stroke often experience neurocognitive and behavioral deficits across multiple domains, yet the added impact of epilepsy remains largely understudied. We examined the effect of comorbid epilepsy on intellectual and executive functioning in pediatric stroke. Method: Participant variables, IQ data, and parent questionnaires (BRIEF) were retrospectively collected from 20 children (n = 10 stroke with epilepsy, “S + E,” n = 10 stroke without epilepsy, “S–E,” matched for gender, age, and stroke type). Inclusion criteria were: history of overt stroke due to a primary vascular cause/disease. Medical records were reviewed and test data were extracted from clinical reports. Results: Intellectual abilities were significantly lower in the S + E group (mean FSIQ = 71, 40% with Intellectual Disability [ID]) compared to the S–E group (mean FSIQ = 91, 0% with ID). Children with comorbid epilepsy demonstrated greater reported problems in nearly all aspects of executive functioning; however, results were not significant. Behavioral regulation skills were notably more problematic for the S + E group (OR = 8.8 for T >60 on BRIEF BRI). The S + E group also had a slightly higher incidence of ADHD (30% vs. 20%). Conclusion(s): Children with comorbid epilepsy demonstrated greater weaknesses in intelligence and aspects of executive functioning, particularly behavioral regulation problems. Additionally, these children were at higher risk for diagnoses of ADHD and ID than those without comorbid epilepsy. Future research examining other variables that predict poor neurocognitive and behavioral outcomes is crucial for assessing pediatric stroke risk factors and designing interventions.

Breastfeeding in children of women taking antiepileptic drugs: cognitive outcomes at age 6 years.

Breastfeeding is known to have beneficial effects, but concern exists that breastfeeding during maternal antiepileptic drug (AED) therapy may be harmful. We previously noted no adverse effects of breastfeeding associated with AED use on IQ at age 3 years, but IQ at age 6 years is more predictive of school performance and adult abilities. To examine the effects of AED exposure via breastfeeding on cognitive functions at age 6 years. Prospective observational multicenter study of long-term neurodevelopmental effects of AED use. Pregnant women with epilepsy receiving monotherapy (ie, carbamazepine, lamotrigine, phenytoin, or valproate) were enrolled from October 14, 1999, through April 14, 2004, in the United States and the United Kingdom. At age 6 years, 181 children were assessed for whom we had both breastfeeding and IQ data. All mothers in this analysis continued taking the drug after delivery. Differential Ability Scales IQ was the primary outcome. Secondary measures included measures of verbal, nonverbal, memory, and executive functions. For our primary analysis, we used a linear regression model with IQ at age 6 years as the dependent variable, comparing children who breastfed with those who did not. Similar secondary analyses were performed for the other cognitive measures. In total, 42.9% of children were breastfed a mean of 7.2 months. Breastfeeding rates and duration did not differ across drug groups. The IQ at age 6 years was related to drug group (P < .001 [adjusted IQ worse by 7-13 IQ points for valproate compared to other drugs]), drug dosage (regression coefficient, -0.1; 95% CI, -0.2 to 0.0; P = .01 [higher dosage worse]), maternal IQ (regression coefficient, 0.2; 95% CI, 0.0 to 0.4; P = .01 [higher child IQ with higher maternal IQ]), periconception folate use (adjusted IQ 6 [95% CI, 2-10] points higher for folate, P = .005), and breastfeeding (adjusted IQ 4 [95% CI, 0-8] points higher for breastfeeding, P = .045). For the other cognitive domains, only verbal abilities differed between the breastfed and nonbreastfed groups (adjusted verbal index 4 [95% CI, 0-7] points higher for breastfed children, P = .03). No adverse effects of AED exposure via breast milk were observed at age 6 years, consistent with another recent study at age 3 years. In our study, breastfed children exhibited higher IQ and enhanced verbal abilities. Additional studies are needed to fully delineate the effects of all AEDs. clinicaltrials.gov Identifier: NCT00021866.

Adolescents With High IQ and Their Adjustment in Adolescence and Midlife

The psychological and social adjustment of high-IQ adolescents (top 10%) were studied for a Swedish cohort born in 1955 (N = 1,326 with IQ data). The focus was on comparing high-IQ adolescents to adolescents of average IQ with regard to their adjustment in adolescence and 30 years later in midlife. The research design enabled us also to study linear and nonlinear relationships of high IQ to adjustment. In adolescence, those with high IQ had better adjustment than those of average IQ in most studied adjustment areas, most strongly so for school achievement, capacity to concentrate, and absence of unhappiness. Data from official records showed that higher IQ was related to less alcohol, criminal, and mental problems in childhood and young adulthood. In midlife, the adjustment differences between those of high IQ and those of average IQ were usually nonsignificant, but for some adjustment indicators, adjustment was moderately worse for the high-IQ group, for instance in global life satisfaction and in satisfaction with friend relations. Controlling for school achievement absorbed almost all significant IQ-adjustment associations, which supports the idea of school achievement as a mediator between IQ and adjustment.

Cognitive Functioning in Young Children with Type 1 Diabetes

The aim of this study was to assess cognitive functioning in children with type 1 diabetes (T1D) and examine whether glycemic history influences cognitive function. Neuropsychological evaluation of 216 children (healthy controls, n = 72; T1D, n = 144) ages 4-10 years across five DirecNet sites. Cognitive domains included IQ, Executive Functions, Learning and Memory, and Processing Speed. Behavioral, mood, parental IQ data, and T1D glycemic history since diagnosis were collected. The cohorts did not differ in age, gender or parent IQ. Median T1D duration was 2.5 years and average onset age was 4 years. After covarying age, gender, and parental IQ, the IQ and the Executive Functions domain scores trended lower (both p = .02, not statistically significant adjusting for multiple comparisons) with T1D relative to controls. Children with T1D were rated by parents as having more depressive and somatic symptoms (p < .001). Learning and memory (p = .46) and processing speed (p = .25) were similar. Trends in the data supported that the degree of hyperglycemia was associated with Executive Functions, and to a lesser extent, Child IQ and Learning and Memory. Differences in cognition are subtle in young children with T1D within 2 years of onset. Longitudinal evaluations will help determine whether these findings change or become more pronounced with time.

Filter Based Receive-Side Spatial Compounding for Veterinary Ultrasound B-Mode Imaging

Veterinary ultrasound has been used in a large number of animal husbandry-related circumstances while many corresponding applications also call for the use of ultrasound in human patients. However, veterinary ultrasound images are affected by speckle, an interference pattern that can reduce the quality and contrast of ultrasound images. In this paper, a filter-based receive-side spatial compounding technique for veterinary ultrasound B-Mode imaging is used to create a compounded veterinary B-Mode image based on multiple looks. In particular, filtering in the lateral direction has been proved to be able to preserve the axial information in the sub-bands and to create decorrelation between sub-bands at the expense of some lateral resolution. A new method was proposed to obtain B-Mode IQ data by special veterinary ultrasonic probe. This approach is tested on 275 in-vivo swine. The effect is accomplished in real-time veterinary ultrasonic imaging with a measurable improvement of SNRe. Meanwhile, the speckle and electronic noise in the compounded image have been greatly reduced and smoothed in the visual result.

A neuropsychological investigation of the Delis-Kaplan Executive Function System

Despite a strong historical association between frontal lobe lesions and executive dysfunction, questions remain regarding the neuropsychological characterization of specific regions within the prefrontal cortex, as well as the utility of some executive function measures. The Delis–Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001) has gained popularity as a collection of executive function tests, but its sensitivity and specificity for detecting focal frontal lobe dysfunction remain uncertain. The current study investigated performances of patients with focal ventromedial prefrontal cortex (vmPFC, n = 13), dorsolateral prefrontal cortex (dlPFC, n = 14), and nonfrontal (NF, n = 18) lesions on the entire D-KEFS battery. We also obtained IQ data from conventional measures (the Wechsler Adult Intelligence Scale–Third Edition and Fourth Edition, WAIS–III/IV). On six D-KEFS indices, patients with dlPFC lesions performed lower than patients with vmPFC and NF lesions. On three other indices, the performances of the dlPFC group were lower than those of the NF group, but did not differ from those of the vmPFC group. However, none of these between-group differences were statistically significant after full-scale IQ and processing speed were controlled for, suggesting that the observed weaknesses in patients with dlPFC lesions were not specific to executive functions. Patients with vmPFC and NF lesions could not be differentiated based on their performances on any D-KEFS measures. While some D-KEFS measures show promise in differentiating patients with dlPFC lesions, the clinical advantage of using the D-KEFS over more traditional measures is not empirically compelling.