IQ Estimates Research Articles

Why do High IQ Societies Differ in Intellectual Achievement? The Role of Schizophrenia and Left‐Handedness in Per Capita Scientific Publications and Nobel Prizes

AbstractPrevious research has attempted to understand why countries with relatively favorable conditions and high estimated average IQs (such as Finland and Japan) have a relatively low per capita number of scientific Nobel prizes. In the present study, we examine whether there is a relationship between national schizophrenia and left‐handedness prevalence, on the one hand, and per capita scientific and literary achievement, on the other hand, in countries with IQ estimates of at least 90. We found that per capita science and literature Nobel prizes and scientific publications are strongly negatively associated with schizophrenia and strongly positively correlated with left‐handedness. There also was a very pronounced negative correlation between schizophrenia rate and left‐handedness rate. These results suggest that genius can be regarded as a combination of very high IQ, aspects of high‐functioning autism (specifically low empathy) plus relatively low impulse control, consistent with observations of intellectually outstanding individuals, and the fact that schizophrenia appears to constitute the opposite pole of these aspects of autism spectrum. We posit differences in androgen levels as a possible underlying explanation for these findings.

The Dutch Bipolar Offspring Study: Cognitive Development and Psychopathology.

Various aspects of the relationship between cognitive impairment and bipolar disorder are not clear yet. This study examines cognitive and educational functioning prospectively in offspring at familial risk for bipolar disorder, in order to improve our understanding of the association between cognitive functioning and psychopathology. Bipolar offspring (N = 92) from the prospective Dutch bipolar offspring study were evaluated at adolescence and adulthood for IQ estimate, educational achievement and development of any psychiatric disorder. The main outcome was IQ estimate after 12years of follow-up (offspring mean age 28years). Generalized estimating equation (GEE) analyses showed that any lifetime DSM-IV axis I diagnosis was related to a lower cognitive outcome at adulthood as compared to unaffected bipolar offspring. No specific association was found for type of diagnosis. Early onset psychopathology (diagnosis at or before age 15years) was significantly related to lower IQ estimate at adulthood, indicating a sensitive period for neurocognitive development.

Clinical utility of the dual n-back task in schizophrenia: A functional imaging approach

The neural correlate of working memory (WM) impairment in schizophrenia is key to the understanding of the cognitive deficits observed in this disorder. We sought to determine the clinical validity of the dual version n-back paradigm in patients with schizophrenia, and whether schizophrenia patients exhibit altered brain activation patterns compared with healthy controls in this dual version WM measure using functional magnetic resonance imaging. Patients with schizophrenia (n = 20) and healthy controls (n = 24) performed the dual n-back task that consists of both visuospatial and auditory-verbal n-back streams, in which participants were required to monitor and update the contents from these two different inputs simultaneously. Significant positive correlations were found between performance in the dual 2-back condition and another measure of WM capacity and IQ estimates. Moreover, hypoactivation was observed at the right middle frontal gyrus and the posterior parietal regions in schizophrenia participants compared with healthy controls. The right hippocampus was less deactivated in schizophrenia patients compared with healthy controls. Our results support the clinical utility of the dual n-back task in schizophrenia and may have implications for the development of specific cognitive training targeting these impaired neural substrates in relation to WM in patients with schizophrenia.

Regional brain atrophy in gray and white matter is associated with cognitive impairment in Myotonic Dystrophy type 1.

Myotonic Dystrophy type 1 (DM1) is a slowly progressive myopathy characterized by varying multisystemic involvement. Several cerebral features such as brain atrophy, ventricular enlargement, and white matter lesions (WMLs) have frequently been described. The aim of this study is to investigate the structural organization of the brain that defines the disease through multimodal imaging analysis, and to analyze the relation between structural cerebral changes and DM1 clinical and neuropsychological profiles. 31 DM1 patients and 57 healthy controls underwent an MRI scan protocol, including T1, T2 and DTI. Global gray matter (GM), global white matter (WM), and voxel-level Voxel Based Morphometry (VBM) and voxel-level microstructural WM abnormalities through Diffusion Tensor Imaging (DTI) were assessed through group comparisons and linear regression analysis with age, degree of muscular impairment (MIRS score), CTG expansion size and neuropsychological outcomes from a comprehensive assessment. Compared with healthy controls, DM1 patients showed a reduction in both global GM and WM volume; and further regional GM decrease in specific primary sensory, multi-sensory and association cortical regions. Fractional anisotropy (FA) was reduced in both total brain and regional analysis, being most marked in frontal, paralimbic, temporal cortex, and subcortical regions. Higher ratings on muscular impairment and longer CTG expansion sizes predicted a greater volume decrease in GM and lower FA values. Age predicted global GM reduction, specifically in parietal regions. At the cognitive level, the DM1 group showed significant negative correlations between IQ estimate, visuoconstructive and executive neuropsychological scores and both global and regional volume decrease, mainly distributed in the frontal, parietal and subcortical regions. In this study, we describe the structural brain signatures that delineate the involvement of the CNS in DM1. We show that specific sensory and multi-sensory - as well as frontal cortical areas - display potential vulnerability associated with the hypothesized neurodegenerative nature of DM1 brain abnormalities.

15 - EFFECTS OF ASSORTATIVE MATING ON ESTIMATES OF SNP HERITABILITY

Background Mates are similar to one another across a large number of traits, including liabilities underlying psychiatric disorders. It has long been known that when such phenotypic similarity implies genetic similarity (hereafter, assortative mating), heritability estimates from family and twin studies can be biased. However, the effects of assortative mating, if any, on estimates of heritability from all SNPs in unrelated individuals (SNP-based heritability, h2SNP) have not been investigated to date. Methods We derived mathematically the expected behavior of estimates from Haseman-Elston regression and GREML, and assessed these predictions via simulation. We then assessed in the UK Biobank whether the predicted signatures of assortative mating on h2SNP were observed. Results We show analytically and via simulation that estimates of h2SNP from both GREML and Haseman-Elston regression are typically biased upwards in the presence of assortative mating. However, estimates from Haseman-Elston regression are roughly constant as a function of sample size and number of markers, whereas the ratio of sample size to number of markers strongly affects those from GREML. This difference in estimate behavior allows one to assess in real data whether assortative mating is affecting estimates of h2SNP. When we did this in the UK Biobank for height and IQ, we observed that h2SNP estimates for height that behaved as predicted, but not for h2SNP estimates for IQ. Discussion For many traits, the degree of bias in estimates of h2SNP is expected to be small, but it can be non-trivial for other traits, depending on the degree of assortative mating and the heritability of the traits. For example, based on spousal similarity, we predict that h2SNP estimates of height and IQ are ~25% greater than their true equilibrium values. That we did not observe the predicted pattern of h2SNP estimates for IQ may either suggest that spousal similarity for IQ occurs via mechanisms that do not lead to genetic similarity (e.g., social homogamy) or that the effects of assortative mating on the covariance between causal variants is counter-acted by the forces of natural selection.

Demographically Calibrated Norms for Two Premorbid Intelligence Measures: The Word Accentuation Test and Pseudo-Words Reading Subtest.

The Word Accentuation Test (WAT, Spanish adaptation of the NART) and the Pseudo-Words (PW) Reading subtest from the Battery for Reading Processes Assessment-Revised (PROLEC-R) are measures to estimate premorbid IQ. This study aims to develop demographically calibrated norms for these premorbid measures in a representative sample of the adult Spanish population in terms of age, education, and sex. A sample of 700 healthy participants from 18 to 86 years old completed the WAT and the PW Reading subtest. The effect of age, years of formal education, and sex on WAT total score, PW total score, and time to complete the PW task (PW time) were analyzed. Percentiles and scalar scores were obtained for each raw score according to nine age ranges and individual education levels. The results indicated a significant effect of age and education on the premorbid performance assessed, with no significant effect of sex. Age and education explained from 1.9 to 33.2% of the variance in premorbid IQ variables. Older participants with fewer years of education obtained worse premorbid IQ estimates. This premorbid IQ estimation decline started in the 56–65 age range for WAT total score and PW time, whereas it started in the 71–75 age range for PW total score. This study reports the first demographic-calibrated norms for WAT and PW Reading subtest for Spanish-speaking population. Even though the influence of age and years of education on premorbid IQ measures was confirmed, the PW Reading subtest showed to be more resistant to decline in elderly population than the WAT.

Is intelligence associated with mortality from lethal force by law enforcement?

Intelligence (IQ) has emerged as an important determinant of many social and health outcomes, and is associated with criminal behavior. This ecological study tested whether IQ was associated with the use of lethal force by law enforcement by examining estimates of state IQ and mortality from lethal force in 50 U.S. states. These data were obtained from a variety of sources freely available on the Internet, including information about mortality from lethal force from a database compiled by a news website, The Guardian. State IQ was negatively correlated with the rate of people killed by law enforcement (r = −0.50, p < .01). This association persisted even after adjusting for numerous demographic and social characteristics; each point increase in state IQ was associated with a 6% reduction in the rate ratio of deaths from lethal force (IRR = 0.94 [95% CI = 0.90, 0.98]). States with higher IQs may have safer communities, and law enforcement officers may act less confrontationally or hostilely during police-suspect encounters in these areas. However, this hypothesis needs to be investigated in future studies using smaller aggregate units for IQ and include more information about neighborhood, law enforcement, and suspect characteristics.

Developing a regression equation for predicting premorbid functioning in an Australian sample using the National Adult Reading Test

ObjectiveIn neuropsychological assessment, predicting the level of premorbid functioning is useful in ascertaining the presence or absence of cognitive decline post‐injury. This study set out to develop regression equations using the National Adult Reading Test (NART) in association with demographic factors to predict the Wechsler Adult Intelligence Scale—Fourth Edition (WAIS‐IV) full‐scale intelligence quotient (FSIQ) and its index scores in a cognitively healthy Australian sample, and to compare the accuracy of these regression equation with the Test of Premorbid Functioning (TOPF) in a clinical sample.MethodThe 111 cognitively healthy male and female participants aged 18–65-years completed a battery of tests, including the WAIS‐IV, NART, and TOPF. The accuracy of the premorbid IQ estimates was then examined on 22 neurologically impaired participants.ResultsThe regression equation using NART errors explained 39.1% of the variance in WAIS‐IV FSIQ. When age, sex, and education were added to the model, the variance increased to 46.6%. Both the regression equations using NART errors and the TOPF significantly over‐estimated IQ in the clinical sample (p < .001), whereas the regression equation combining errors and demographics, and the TOPF with demographic correction, did not.ConclusionEstimating premorbid functioning is an important aspect of neuropsychological assessment. This paper developed a series of regression equations using the NART which are suitable for the Australian context.

White matter disruptions in patients with bipolar disorder

Bipolar disorder (BD) patients show aberrant white matter microstructure compared to healthy controls but little is known about the relation with clinical characteristics. We therefore investigated the relation of white matter microstructure with the main pharmacological treatments as well its relation with IQ. Patients with BD (N = 257) and controls (N = 167) underwent diffusion tensor imaging (DTI) and comprehensive clinically assessments including IQ estimates. DTI images were analyzed using tract-based spatial statistics. Fractional anisotropy (FA) and Mean Diffusivity (MD) were determined. Patients had significantly lower FA and higher MD values throughout the white matter skeleton compared to controls. Within the BD patients, lithium use was associated with higher FA and lower MD. Antipsychotic medication use in the BD patients was not associated with FA but, in contrast to lithium, was associated with higher MD. IQ was significantly positively correlated with FA and negatively with MD in patients as well as in controls. In this large DTI study we found evidence for marked differences in FA and MD particularly in (but not restricted to) corpus callosum, between BD patients and controls. This effect was most pronounced in lithium-free patients, implicating that lithium affects white matter microstructure and attenuates differences associated with bipolar disorder. Effects of antipsychotic medication intake were absent in FA and only subtle in MD relative to those of lithium. The abnormal white matter microstructure was associated with IQ but not specifically for either group.

Comparison of methods for estimating premorbid intelligence

ABSTRACTTo evaluate impact of neurological injury on cognitive performance it is typically necessary to derive a baseline (or “premorbid”) estimate of a patient’s general cognitive ability prior to the onset of impairment. In this paper, we consider a range of common methods for producing this estimate, including those based on current best performance, embedded “hold/no-hold” tests, demographic information, and word reading ability. Ninety-two neurologically healthy adult participants were assessed on the full Wechsler Adult Intelligence Scale – Fourth Edition (WAIS-IV; Wechsler, D. (2008). Wechsler Adult Intelligence Scale (4th ed.). San Antonio, TX: Pearson Assessment.) and on two widely used word reading tests: National Adult Reading Test (NART; Nelson, H. E. (1982). National Adult Reading Test (NART): For the assessment of premorbid intelligence in patients with dementia: Test manual. Windsor: NFER-Nelson.; Nelson, H. E., & Willison, J. (1991). National Adult Reading Test (NART). Windsor: NFER-Nelson.) and Wechsler Test of Adult Reading (WTAR; Wechsler, D. (2001). Wechsler Test of Adult Reading: WTAR. San Antonio, TX: Psychological Corporation.). Our findings indicate that reading tests provide the most reliable and precise estimates of WAIS-IV full-scale IQ, although the addition of demographic data provides modest improvement. Nevertheless, we observed considerable variability in correlations between NART/WTAR scores and individual WAIS-IV indices, which indicated particular usefulness in estimating more crystallised premorbid abilities (as represented by the verbal comprehension and general ability indices) relative to fluid abilities (working memory and perceptual reasoning indices). We discuss and encourage the development of new methods for improving premorbid estimates of cognitive abilities in neurological patients.

Prevalence of Attention Deficit Hyperactivity Disorder among Preschool Children (3-6 Years), Menoufia Governorate

Background: Attention deficit hyperactivity disorder (ADHD) is the most common neurobehavioral disorder in children and adolescents. It is characterized by inattention and hyperactivity-impulsivity that often results in behavioral and academic difficulties. It affects about 3 - 12% of children with a male to female ratio varying from 3:1 to 9:1.Objectives: To estimate the prevalence and identifying possible risk factors of attention deficit hyperactivity disorder among preschool children (3-6 years), at Menoufia governorate. Methods: A cross-sectional comparative study was carried out in Menoufia governorate during the period from 15th March 2016 to 1st April 2018. The study included 572 preschool children (308) male and (264) female. They had been chosen from the preschool classes (KG1and KG2) in the randomly selected schools. Written consents were taken from children caregivers to participate in the study. Parents and teachers were the respondent to the Arabic version of Conner’s questionnaire. Suspected cases were confirmed and categorized by DSM-V criteria. Affected children and control group were subjected to medical and psychological assessment, IQ estimation and laboratory investigations. Results: Prevalence of attention deficit hyperactivity disorder among preschool children was 9.30%. It was higher in males (69.8%) with a male to female ratio about 2:1. Main risk factors were low socioeconomic level, large family size, living with a single parent and positive consanguinity. Conclusion: ADHD presents a troublesome problem among preschool children at Menoufia governorate. Collaborative efforts are required for early detection and management.

Utility of an abbreviated version of the stanford-binet intelligence scales (5th ed.) in estimating 'full scale' IQ for young children with autism spectrum disorder.

We investigated the utility of a shortened version of the Stanford-Binet Intelligence Scales in estimating IQ for 40 young children with autism spectrum disorder (ASD). The findings provide qualified support for the instrument: acceptably accurate IQ estimation was achieved for most cases; but not so for a sizeable minority (17.5%). Careful clinical judgment is necessary to determine the applicability of the ABIQ to individual cases.

Theory of mind impairment and its clinical correlates in patients with schizophrenia, major depressive disorder and bipolar disorder

BackgroundAlthough Theory of Mind (ToM) impairment has been observed in patients with a wide range of mental disorders, the similarity and uniqueness of these deficits across diagnostic groups has not been thoroughly investigated. MethodsWe recruited 35 participants with schizophrenia (SCZ), 35 with bipolar disorder (BD), 35 with major depressive disorder (MDD), and 35 healthy controls in this study. All participants were matched in age, gender proportion and IQ estimates. The Yoni task, capturing both the cognitive and affective components of ToM at the first- and second-order level was administered. Repeated-measure ANOVA and MANOVA were conducted to compare the group differences in ToM performance. A network was then constructed with ToM performances, psychotic and depressive symptoms, and executive function as nodes exploring the clinical correlates of ToM. ResultsOverall, ToM impairments were observed in all patient groups compared with healthy controls, with patients with SCZ performing worse than those with BD. In second-order conditions, patients with SCZ and MDD showed deficits in both cognitive and affective conditions, while patients with BD performed significantly poorer in cognitive conditions. Network analysis showed that second-order affective ToM performance was associated with psychotic and depressive symptoms as well as executive dysfunction, while second-order affective ToM performance and negative symptoms showed relatively high centrality in the network. ConclusionsPatients with SCZ, MDD and BD exhibited different types and severity of impairments in ToM sub-components. Impairment in higher-order affective ToM appears to be closely related to clinical symptoms in both psychotic and affective disorders.

The Association Between PTSD and Functional Outcome Is Mediated by Perception of Cognitive Problems Rather Than Objective Neuropsychological Test Performance.

Posttraumatic stress disorder (PTSD) has been consistently linked to poorer functional outcomes, including quality of life, health problems, and social and occupational functioning. Less is known about the potential mechanisms by which PTSD leads to poorer functional outcomes. We hypothesized that neurocognitive functioning and perception of cognitive problems would both mediate the relationship between PTSD diagnosis and functioning. In a sample of 140 veterans of the recent wars and conflicts in Iraq and Afghanistan, we assessed PTSD symptoms, history of traumatic brain injury (TBI), depression, self-report measures of quality of life, social and occupational functioning, and reintegration to civilian life, as well as perception of cognitive problems. Veterans also completed a comprehensive neuropsychological battery of tests. Structural equation modeling revealed that perception of cognitive problems, but not objective neuropsychological performance, mediated the relationship between PTSD diagnosis and functional outcomes after controlling for TBI, depression, education, and a premorbid IQ estimate, b = -6.29, 95% bias-corrected bootstrapped confidence interval [-11.03, -2.88], showing a large effect size. These results highlight the importance of addressing appraisals of posttrauma cognitive functioning in treatment as a means of improving functional outcomes.

Linguistic camouflage in girls with autism spectrum disorder

BackgroundAutism spectrum disorder (ASD) is diagnosed more frequently in boys than girls, even when girls are equally symptomatic. Cutting-edge behavioral imaging has detected “camouflaging” in girls with ASD, wherein social behaviors appear superficially typical, complicating diagnosis. The present study explores a new kind of camouflage based on language differences. Pauses during conversation can be filled with words like UM or UH, but research suggests that these two words are pragmatically distinct (e.g., UM is used to signal longer pauses, and may correlate with greater social communicative sophistication than UH). Large-scale research suggests that women and younger people produce higher rates of UM during conversational pauses than do men and older people, who produce relatively more UH. Although it has been argued that children and adolescents with ASD use UM less often than typical peers, prior research has not included sufficient numbers of girls to examine whether sex explains this effect. Here, we explore UM vs. UH in school-aged boys and girls with ASD, and ask whether filled pauses relate to dimensional measures of autism symptom severity.MethodsSixty-five verbal school-aged participants with ASD (49 boys, 16 girls, IQ estimates in the average range) participated, along with a small comparison group of typically developing children (8 boys, 9 girls). Speech samples from the Autism Diagnostic Observation Schedule were orthographically transcribed and time-aligned, with filled pauses marked. Parents completed the Social Communication Questionnaire and the Vineland Adaptive Behavior Scales.ResultsGirls used UH less often than boys across both diagnostic groups. UH suppression resulted in higher UM ratios for girls than boys, and overall filled pause rates were higher for typical children than for children with ASD. Higher UM ratios correlated with better socialization in boys with ASD, but this effect was driven by increased use of UH by boys with greater symptoms.ConclusionsPragmatic language markers distinguish girls and boys with ASD, mirroring sex differences in the general population. One implication of this finding is that typical-sounding disfluency patterns (i.e., reduced relative UH production leading to higher UM ratios) may normalize the way girls with ASD sound relative to other children, serving as “linguistic camouflage” for a naïve listener and distinguishing them from boys with ASD. This first-of-its-kind study highlights the importance of continued commitment to understanding how sex and gender change the way that ASD manifests, and illustrates the potential of natural language to contribute to objective “behavioral imaging” diagnostics for ASD.

The use of neuropsychological tests to assess intelligence

Objective: We sought to derive a ‘neuropsychological intelligence quotient’ (NIQ) to replace IQ testing in some routine assessments. Method: We administered neuropsychological testing and a seven-subtest short form of the Wechsler Adult Intelligence Scale to a community sample of 394 adults aged 18–96 years. We regressed Wechsler Full Scale IQs (W-FSIQ) on 23 neuropsychological scores and derived an NIQ from 9 measures that explained significant variance in W-FSIQ. We then compared subgroups of 284 healthy and 108 unhealthy participants in NIQ and W-FSIQ to assess criterion validity, correlated NIQ and W-FSIQ scores with education level and independence for activities of daily living to assess convergent validity, and compared validity coefficients for the NIQ with those of ‘hold’ and ‘no-hold’ indices. Results: By design, NIQ and W-FSIQ scores correlated highly (r = .84), and both were higher in healthy participants. The difference was larger for NIQ, which accounted for more variability in activities of daily living. The NIQ and ‘no-hold’ index were better predicted by health status and less predicted by educational status than the ‘hold’ index. Conclusions: We constructed an NIQ that correlates highly with Wechsler FSIQ. Tests required to obtain NIQ are commonly used and can be administered in about 45 min. Validity properties of NIQ and W-FSIQ are similar. The NIQ bore greater resemblance to a ‘no-hold’ than ‘hold’ index. One can obtain a reasonably accurate estimate of current Full Scale IQ without formal intelligence testing from a brief neuropsychological battery.

Estimating Self and Spouse Intelligence among Jordanians

The current study aimed at exploring self and spouse estimates of general and multiple intelligences among a sample of married Jordanian Students. Two-hundred and ten participants, recruited from Yarmouk and Al-Balqaa Universities, Jordan, completed a brief questionnaire based on those used in previous research which included an estimation of general IQ and each of the multiple intelligence sub-types. Results of the study partially replicated the results from other multiple intelligence self-estimate studies showing sex differences on general and logical intelligences, and confirmed previous research results that estimated verbal (linguistic) intelligence followed by numerical (logical) intelligence are the best significant predictors of estimated general intelligence. These results were discussed in terms of sex and cultural differences and some recommendations were made

Estimating Self and Spouse Intelligence among Jordanians

The current study aimed at exploring self and spouse estimates of general and multiple intelligences among a sample of married Jordanian Students. Two-hundred and ten participants, recruited from Yarmouk and Al-Balqaa Universities, Jordan, completed a brief questionnaire based on those used in previous research which included an estimation of general IQ and each of the multiple intelligence sub-types. Results of the study partially replicated the results from other multiple intelligence self-estimate studies showing sex differences on general and logical intelligences, and confirmed previous research results that estimated verbal (linguistic) intelligence followed by numerical (logical) intelligence are the best significant predictors of estimated general intelligence. These results were discussed in terms of sex and cultural differences and some recommendations were made

The National Adult Reading Test: restandardisation against the Wechsler Adult Intelligence Scale—Fourth edition

ABSTRACTSince publication in 1982, the 50-item National Adult Reading Test (NART; Nelson, 1982; NART–R; Nelson & Willison, 1991) has remained a widely adopted method for estimating premorbid intelligence both for clinical and research purposes. However, the NART has not been standardised against the most recent revisions of the Wechsler Adult Intelligence Scale (WAIS-III; Wechsler, 1997, and WAIS-IV; Wechsler, 2008). Our objective, therefore, was to produce reliable standardised estimates of WAIS-IV IQ from the NART. Ninety-two neurologically healthy British adults were assessed and regression equations calculated to produce population estimates of WAIS-IV full-scale IQ (FSIQ) and constituent index scores. Results showed strong NART/WAIS-IV FSIQ correlations with more moderate correlations observed between NART error and constituent index scores. FSIQ estimates were closely similar to the published WAIS and WAIS-R estimates at the high end of the distribution, but at the lower end were approximately equidistant from the highly discrepant WAIS (low) and WAIS-R (high) values. We conclude that the NART is likely to remain an important tool for estimating the impact of neurological damage on general cognitive ability. We advise caution in the use of older published WAIS and/or WAIS-R estimates for estimating premorbid WAIS-IV FSIQ, particularly for those with low NART scores.

Utility of the General Ability Index (GAI) and Cognitive Proficiency Index (CPI) with survivors of pediatric brain tumors: Comparison to Full Scale IQ and premorbid IQ estimates

ABSTRACTIntroduction. Pediatric brain tumor survivors are at risk for working memory and processing speed impairment. The General Ability Index (GAI) provides an estimate of intellectual functioning that is less influenced by working memory and processing speed than a Full Scale IQ (FSIQ). The Cognitive Proficiency Index (CPI) provides a measure of efficient information processing derived from working memory and processing speed tasks. We examined the utility of the GAI and CPI to quantify neurocognitive outcomes in a sample of pediatric brain tumor survivors. Method. GAI, CPI, and FSIQ scores from the Wechsler Intelligence Scale for Children–Fourth Edition (WISC–IV) were examined for 57 pediatric brain tumor survivors (ages 6–16 years) treated with cranial radiation therapy (RT). Results. GAI scores were higher than FSIQ and CPI scores, both p < .001. Lower CPI scores were associated with history of craniospinal irradiation and time since RT. Lower FSIQ and GAI scores were associated with higher RT dose and time since RT. The rate of clinically significant GAI–FSIQ discrepancies in our sample was greater than that observed in the WISC–IV standardization sample, p < .001. Estimated premorbid IQ scores were higher than GAI, p < .01, and FSIQ scores, p < .001. Conclusions. Pediatric brain tumor survivors exhibit weaker cognitive proficiency than that expected for age, while general reasoning ability remains relatively spared. The GAI may be useful to quantify the intellectual potential of a survivor when appropriate accommodations are in place for relative cognitive proficiency weaknesses. The CPI may be a particularly sensitive outcome measure of treatment-related cognitive change in this population.