IQ Estimates Research Articles

Theory of Mind as an endophenotype for schizophrenia spectrum disorder: Study in first episode of psychosis patients and first-degree relatives

BackgroundDeficits in Theory of Mind (ToM) had been suggested as a possible endophenotype for unaffected relatives of first episode of psychosis (FEP) patients. There are a limited number of studies which have evaluated ToM deficits among the siblings and parents of FEP patients. AimThis study aimed to explore ToM deficits and its correlates among FEP patients, their siblings, parents, and controls. MethodologyFEP patients (N=102), their parents (N=135), siblings (N=97), and controls (N=167) were evaluated on ToM performance with the Reading the Mind in the Eyes Test (Eyes Test). Interview for sociodemographic variables of age, sex, years of education, and IQ estimation and neurocognitive tests were administered to all groups. ResultsFEP patients had a significantly lower performance on the Eyes Test compared to their siblings and controls. However, no significant differences were found between siblings and parents or siblings and controls. ConclusionAttending our results, we found no evidence for ToM deficits as an endophenotype of SSDs. Furthermore, ToM accuracy may be mediated by interaction with other cognitive domains and play a protective role against psychosis in unaffected siblings.

Sex differences in the temporal dynamics of autistic children’s natural conversations

BackgroundAutistic girls are underdiagnosed compared to autistic boys, even when they experience similar clinical impact. Research suggests that girls present with distinct symptom profiles across a variety of domains, such as language, which may contribute to their underdiagnosis. In this study, we examine sex differences in the temporal dynamics of natural conversations between naïve adult confederates and school-aged children with or without autism, with the goal of improving our understanding of conversational behavior in autistic girls and ultimately improving identification.MethodsForty-five school-aged children with autism (29 boys and 16 girls) and 47 non-autistic/neurotypical (NT) children (23 boys and 24 girls) engaged in a 5-min “get-to-know-you” conversation with a young adult confederate that was unaware of children’s diagnostic status. Groups were matched on IQ estimates. Recordings were time-aligned and orthographically transcribed by trained annotators. Several speech and pause measures were calculated. Groups were compared using analysis of covariance models, controlling for age.ResultsAutistic girls used significantly more words than autistic boys, and produced longer speech segments than all other groups. Autistic boys spoke more slowly than NT children, whereas autistic girls did not differ from NT children in total word counts or speaking rate. Autistic boys interrupted confederates’ speech less often and produced longer between-turn pauses (i.e., responded more slowly when it was their turn) compared to other children. Within-turn pause duration did not differ by group.LimitationsOur sample included verbally fluent children and adolescents aged 6–15 years, so our study results may not replicate in samples of younger children, adults, and individuals who are not verbally fluent. The results of this relatively small study, while compelling, should be interpreted with caution and replicated in a larger sample.ConclusionThis study investigated the temporal dynamics of everyday conversations and demonstrated that autistic girls and boys have distinct natural language profiles. Specifying differences in verbal communication lays the groundwork for the development of sensitive screening and diagnostic tools to more accurately identify autistic girls, and could inform future personalized interventions that improve short- and long-term social communication outcomes for all autistic children.

Joint Compensation of TX/RX IQ Imbalance and Channel Parameters for OTSM Systems

Orthogonal time sequency multiplexing (OTSM), robust to doubly-selective fading channel, performs similar to orthogonal time frequency space (OTFS) system with less modulation/demodulation complexity. Direct conversion OTSM system suffers from hardware impairments such as in-phase and quadrature phase (IQ) imbalance at the transmitter (TX) and receiver (RX). At high frequencies, hardware imperfections are inevitable and should be compensated for better performance. In this Letter, we propose joint estimation of TX and RX IQ imbalance and estimate channel parameters in the delay time domain using pseudo noise based training sequence approach. The mean square error of the estimated channel parameters reduce with increase in training sequence length and power. With matched filtered Gauss-Seidel iterative method of detection of low complexity, it is shown that the compensated system performs close to ideal system under fractional delay and fractional Doppler.

Neuropsychological and Symptom Predictors of Diagnostic Persistence in ADHD: A 25-Year Follow-up Study

Background: This study extends long-term predictive research on ADHD by including both neuropsychological and symptom measures at baseline in adolescence as predictors of diagnostic persistence 25 years later. Methods: Nineteen males with ADHD and 26 healthy controls (HC; M/F = 13/13), were assessed in adolescence and 25 years later. Measurements at baseline included a comprehensive test battery measuring eight neuropsychological domains, an IQ estimate, the Child Behavior Checklist (CBCL), and the Global Assessment Scale of Symptoms. Differences between ADHD Retainers, Remitters, and HC were calculated with ANOVAs, and potential predictions of differences in the ADHD group by linear regression analyses. Results: Eleven (58%) participants retained their ADHD diagnoses at follow-up. Motor Coordination and Visual perception at baseline predicted diagnosis at follow-up. CBCL Attention problems at baseline in the ADHD group predicted variance in diagnostic status. Conclusion: Lower-order neuropsychological functions related to motor function and perception are important long-time predictors of persistence of ADHD.

National Mean IQ Estimates: Validity, Data Quality, and Recommendations

National Mean IQ Estimates: Validity, Data Quality, and Recommendations

MCI performance classification improves with a brief vocabulary test

AbstractBackgroundScores on cognitive tests in the bottom 7% of normative distributions are consistent with the possible diagnosis of mild cognitive impairment (MCI). The identification of patients with MCI is improved by correcting for the influence of demographic factors such as Age, Education, and Gender (AEG), on performance. Here, we evaluated whether estimates of premorbid verbal IQ derived from a brief vocabulary test would further improve classification accuracy.MethodWe obtained vocabulary scores from 441 healthy adults (mean age = 65.1 ±14.4) using the 4‐min vocabulary subtest of the California Cognitive Assessment Battery (CCAB). The vocabulary subtest included 24 multiple choice items that adapted in difficulty based on the examinee responses using a 2:1 staircase with adjustable step sizes (Figure 1). Tests were telemedically administered in participants’ homes by an experienced proctor who monitored performance via a web‐based interface.ResultUnlike cognitive measures of fluid intelligence, vocabulary scores improved significantly with Age (r = 0.25, p < 0.001, Figure 2). Scores were also higher for participants with more education and female gender. Vocabulary z‐scores were therefore calculated after correcting for the influence of Age, Education, and Gender. Vocabulary z‐scores correlated significantly with total recall scores on the Bay Area Verbal Learning Test (BAVLT, n = 398 participants, r = 0.35, p < 0.001) and significantly improved model fit when added to AEG regressors (z = 2.1, p< 0.02 one tailed)L the AEG model accounted for 25.6% of BAVLT score variance, whereas the AEG+vocabulary (AEG+V) model accounted for 34.7% of variance. AEG and AEG+V models classified different participants in the MCI performance range: 44% of participants in the lowest 7% of scores in the AEG+V model fell within the normal range in the AEG model, while 32% of participants classified as MCI in the AEG model fell within the normal range on the AEG+V model (Figure 3).ConclusionThe current results suggest that a brief vocabulary test improves MCI classification accuracy among older participants.

Estimating Intelligence Quotient Using Stylometry and Machine Learning Techniques: A Review

The task of trying to quantify a person's intelligence has been a goal of psychologists for over a century. The area of estimating IQ using stylometry has been a developing area of research and the effectiveness of using machine learning in stylometry analysis for the estimation of IQ has been demonstrated in literature whose conclusions suggest that using a large dataset could improve the quality of estimation. The unavailability of large datasets in this area of research has led to very few publications in IQ estimation from written text. In this paper, we review studies that have been done in IQ estimation and also that have been done in author profiling using stylometry and we conclude that based on the success of IQ estimation and author profiling with stylometry, a study on IQ estimation from written text using stylometry will yield good results if the right dataset is used.

The "Dutch Reading Test for Adults" has Been Used for 29 Years to Estimate the Premorbid Performance Level, does it Still Meet the Expectations?

To detect cognitive change after brain damage, it is important to know the level of premorbid intellectual functioning. A popular instrument in this context is the “Nederlandse Leestest voor Volwassenen” (NLV; Schmand et al., 1992). In this test, 50 words with irregular pronunciation must be read out loud. The score on this test used to be considered as a good estimate of someone’s premorbid IQ, due to high correlations with the Verbal and Full-Scale IQ estimates of the WAIS (Verbal IQ: r = .85, Full Scale IQ: r = .74; Schmand et al., 1992). Despite some updates of the normative data (e.g., Bouma et al., 2012), the validity of the test has not been re-evaluated since. The aim of the current study was to evaluate whether the NLV still correlates sufficiently with the WAIS-IV to warrant its proper use as a psychodiagnostic tool. In Study 1, 30 participants (age range: 20–29 year) were tested, and in Study 2, 51 participants (age range: 45–65 year). We checked whether the NLV-generated IQ-score estimates correlated with the different IQ indices of the WAIS-IV. In the younger group, no correlations were found between the NLV-generated IQ-score estimate and any of the WAIS-IV indices nor the Full-Scale IQ. In the older group, the NLV-generated IQ-score estimate correlated with Full scale IQ and the indices of Verbal Comprehension, Working Memory and Processing Speed. These correlations were all <.46 which is far below the typically hold standard in test development of >.70. Based on these findings we conclude the NLV in its current form is not appropriate anymore to estimate premorbid IQ in both young and older adults.

When is it appropriate to infer cognitive impairment on the basis of premorbid IQ estimates? A simulation study.

Whether an individual meets psychometric criteria for cognitive impairment is dictated by the comparison criterion, which is typically either a normative mean or a known or estimated previous level of ability. This study investigated the conditions under which adjusting normative expectations based on estimated premorbid intelligence would be appropriate. A simulated data set was derived and several parameters were systematically varied: the correlation between premorbid intelligence and the cognitive test score, the cutoff used to classify a score as "normal" or "abnormal", and the population base rate of cognitive impairment. Simulation results demonstrated that the correlation between premorbid intelligence and the cognitive score was the only parameter to substantially influence the trade-off between the two normative approaches, with correlations above ρ = .35 signifying greater advantage to adjusting normative expectations by premorbid intelligence. These findings inform common neuropsychological practices regarding the application of premorbid intelligence estimates to the detection of cognitive impairment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Course of intellectual functioning in schizophrenia and bipolar disorder: a 10-year follow-up study.

Intellectual functioning (IQ) is lower in schizophrenia patients compared to healthy controls, with bipolar patients intermediate between the two. Declines in IQ mark the onset of schizophrenia, while stability is generally found post-onset. There are to date few studies on long-term IQ development in bipolar disorder. This study presents 10-year follow-up data on IQ, including premorbid IQ estimates, to track the developmental course from pre-onset levels to long-term outcomes in both patient groups compared to healthy controls. We included 139 participants with schizophrenia, 76 with bipolar disorder and 125 healthy controls. Mixed model analyses were used to estimate developmental slopes for IQ scores from estimated premorbid level (NART IQ) through baseline (WASI IQ) measured within 12 months post-onset, to 10-year follow-up (WASI IQ), with pairwise group comparisons. The best fit was found using a model with a breakpoint at baseline assessment. Only the schizophrenia group had significant declines from estimated premorbid to baseline IQ levels compared to controls. When comparing patient groups, schizophrenia patients had steeper declines than the bipolar group. Increases in IQ were found in all groups over the follow-up period. Trajectories of IQ from premorbid level to 10-year follow-up indicated declines from estimated premorbid level to illness onset in both patient groups, followed by increases during the follow-up period. Schizophrenia patients had a steeper decline than bipolar patients. During follow-up, increases indicate developmental improvement for both patient groups, but with a maintained lag compared to healthy controls due to lower premorbid levels.

Neuropsychological Profiles of Athletes and Views of Parents Choosing Flag Versus Tackle Football Participation.

Background:Previous studies have found that injury rates are slightly higher in children who play flag football versus tackle football. It is unclear if this difference is due to the way each type is played or taught or whether there are intrinsic differences in attitudes or neuropsychological characteristics in children and their parents.Purpose:To determine whether children who play flag football score differently from those who play tackle football on validated neuropsychological tests.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Each participating athlete (aged 8-12 years) was recruited in 2018 and 2019 by email through local youth football leagues and the local university. Each athlete was administered a 1-time multidimensional assessment battery. The battery included the Wechsler Abbreviated Scale of Intelligence-2nd Edition, the children’s version of the Trail Making Test, the Integrated Digit Span and Spatial Span subtests of the Wechsler Intelligence Scale for Children-4th Edition (WISC-IV), and the Beck Self-Concept Inventory for Youth. The parent/guardian of each athlete completed the Achenbach Child Behavior Checklist-Parent Report Form, the Behavior Rating Inventory of Executive Function (BRIEF)-Parent Form, and a custom survey. These tests were used to determine IQ estimates and standardized scores, measuring verbal comprehension, matrix reasoning, mental set-shifting, attention, cognitive processing speed, working memory, spatial processing, perception of self-concept, behavioral regulation index, metacognition index, and global executive composite. Scores were compared between flag football and tackle football groups by 2-sample t test, with the Wilcoxon rank-sum test used for nonparametric data.Results:A total of 64 athletes (41 tackle football, 23 flag football) were enrolled from youth football leagues (grades 4-6). Flag players scored significantly higher on the WISC-IV Spatial Span-Backward subtest (scaled mean, 12.0 vs 10.6; P = .046), while tackle players had significantly higher BRIEF-Inhibit subscores (mean t-score, 45 vs 42; P = .026). There were no significant differences in any of the other tests, including socioeconomic status and perceived concussion risks.Conclusion:Concerns that injury epidemiologic studies comparing flag with tackle football could be confounded by intrinsic differences in the children who choose to play each type seem to be unfounded.

Updated IQ and Well-Being Scores for the 50 U.S. States.

At the level of the 50 U.S. states, an interconnected nexus of well-being variables exists. These variables strongly correlate with estimates of state IQ in interesting ways. However, the state IQ estimates are now more than 16 years old, and the state well-being estimates are over 12 years old. Updated state IQ and well-being estimates are therefore needed. Thus, I first created new state IQ estimates by analyzing scores from both the Program for the International Assessment of Adult Competency (for adults), and the National Assessment of Educational Progress (for fourth and eighth grade children) exams. I also created new global well-being scores by analyzing state variables from the following four well-being subdomains: crime, income, health, and education. When validating the nexus, several interesting correlations existed among the variables. For example, state IQ most strongly predicted FICO credit scores, alcohol consumption (directly), income inequality, and state temperature. Interestingly, state IQ derived here also correlated 0.58 with state IQ estimates from over 100 years ago. Global well-being likewise correlated with many old and new variables in the nexus, including a correlation of 0.80 with IQ. In sum, at the level of the U.S. state, a nexus of important, strongly correlated variables exists. These variables comprise well-being, and state IQ is a central node in this network.

A Psychometric Analysis of Raven's Colored Progressive Matrices: Evaluating Guessing and Carelessness Using the 4PL Item Response Theory Model.

The purpose of the present study was to evaluate the psychometric properties of Raven’s colored progressive matrices by estimating the presence of pseudo-guessing and pseudo-carelessness. Participants were 1127 children from ages 5 to 11. Guessing and carelessness were assessed using the lower and upper asymptotes of the 3PL and 4PL item response theory (IRT) models, respectively. Optimal model fit was judged using difference loglikelihood tests and information criteria. Results indicated that guessing, but not carelessness, were evident in the AB and B forms of the CPM, with successful guessing being more prevalent in the AB form. It is concluded that nonverbal IQ estimation in CPM should include variable estimation methods so that aptitude scores are estimated with the highest possible accuracy.

Supplemental Material for When Is It Appropriate to Infer Cognitive Impairment on the Basis of Premorbid IQ Estimates? A Simulation Study

Supplemental Material for When Is It Appropriate to Infer Cognitive Impairment on the Basis of Premorbid IQ Estimates? A Simulation Study

Frailty Syndrome Is Associated with Poorer Self-Reported Sleep Quality Among Older Persons with Human Immunodeficiency Virus.

Older people with HIV (PWH) experience heightened risk for the acquisition of cumulative, multisystem decline, that is, frailty syndrome. Frailty relates to poorer sleep quality in the general older adult population; however, this association has yet to be explored among PWH. A cross-sectional analysis of 285 PWH ≥50 years of age (mean age 60.5 ± 7.0) examined the relationship between frailty (Fried frailty phenotype) and self-reported sleep quality [Pittsburgh Sleep Quality Index (PSQI)]. Three separate multivariable linear regression models examined global PSQI as a function of (1) frailty phenotype, (2) total number of frailty symptoms, or (3) specific individual frailty symptoms. Models covaried for demographic and biopsychosocial risk factors, including age, sex, race/ethnicity, education, premorbid verbal IQ estimate, current depressive symptoms, and diagnosis of a substance abuse disorder. Compared to nonfrail (B = 0.151; p = .021) and prefrail (B = 0.144; p = .021), frail phenotype was related to poorer sleep quality (increased global PSQI; F(5,278) = 11.34, p < .001; R2 = 0.17). Increased number of frailty symptoms (B = 0.144; p = .019; F(4,276) = 12.719, p < .001; R2 = 0.16) and exhaustion was associated with increased global PSQI scores (B = 0.218, p < .001; F(6,247) = 10.436, p < .001; R2 = 0.19). In all models, older age, female sex, and elevated current depressive symptoms were associated with poorer sleep quality. In older PWH, greater frailty symptoms related to poorer sleep quality, independent of psychosocial risk factors for poor sleep. Frailty and poor sleep individually have adverse effects on health and everyday functioning; thus, establishing this association may better aid providers to screen for and treat problems with sleep quality and/or frailty among PWH.

Longitudinal Stability of Intellectual Functioning in Autism Spectrum Disorder: From Age 3 Through Mid-adulthood

Intelligence (IQ) scores are used in educational and vocational planning for individuals with autism spectrum disorder (ASD) yet little is known about the stability of IQ throughout development. We examined longitudinal age-related IQ stability in 119 individuals with ASD (3–36 years of age at first visit) and 128 typically developing controls. Intelligence measures were collected over a 20-year period. In ASD, Full Scale (FSIQ) and Verbal (VIQ) Intelligence started lower in childhood and increased at a greater rate with age relative to the control group. By early adulthood, VIQ and working memory stabilized, whereas nonverbal and perceptual scores continued to change. Our results suggest that in individuals with ASD, IQ estimates may be dynamic in childhood and young adulthood.

Associations between the Mediterranean Diet Pattern and Weight Status and Cognitive Development in Preschool Children.

Cognitive dysfunctions are a global health concern. Early-life diet and weight status may contribute to children’s cognitive development. For this reason, we explored the associations between habitual food consumption, body mass index (BMI) and cognitive outcomes in 54 preschool children belonging to the Pisa birth Cohort (PISAC). We estimated groups of foods, nutrients and calorie intakes through a food frequency questionnaire (FFQ) and Italian national databases. Then, we adopted the Mediterranean diet (MD) score to assess relative MD adherence. Cognition was examined using the Griffiths Mental Development Scales-Extended Revised (GMDS-ER). We found that higher, compared to low and moderate, adherence to MD was associated with higher performance scores. Furthermore, white meat consumption was positively related to BMI, and BMI (age–gender specific, z-scores) categories were negatively related to practical reasoning scores. All associations were independent of maternal IQ estimates, parents’ socioeconomic status, exclusive/non-exclusive breastfeeding, actual age at cognitive assessment and gender. In conclusion, in preschool children, very high adherence to MD seemed protective, whereas BMI (reinforced by the intake of white meat) was negatively associated with cognition.

Disrupted structural connectome and neurocognitive functions in Duchenne muscular dystrophy: classifying and subtyping based on Dp140 dystrophin isoform.

Neurocognitive disabilities in Duchenne muscular dystrophy (DMD) children beginning in early childhood and distal DMD gene deletions involving disruption of Dp140 isoform are more likely to manifest significant neurocognitive impairments. MRI data analysis techniques like brain-network metrics can provide information on microstructural integrity and underlying pathophysiology. A prospective study on 95 participants [DMD = 57, and healthy controls (HC) = 38]. The muscular dystrophy functional rating scale (MDFRS) scores, neuropsychology batteries, and multiplex ligand-dependent probe amplification (MLPA) testing were used for clinical assessment, IQ estimation, and genotypic classification. Diffusion MRI and network-based statistics were used to analyze structural connectomes at various levels and correlate with clinical markers. Motor and executive sub-networks were extracted and analyzed. Out of 57 DMD children, 23 belong to Dp140 + and 34 to Dp140- subgroup. Motor disabilities are pronounced in Dp140- subgroup as reflected by lower MDFRS scores. IQ parameters are significantly low in all-DMD cases; however, the Dp140- has specifically lowest scores. Significant differences were observed in global efficiency, transitivity, and characteristic path length between HC and DMD. Subgroup analysis demonstrates that the significance is mainly driven by participants with Dp140- than Dp140 + isoform. Finally, a random forest classifier model illustrated an accuracy of 79% between HC and DMD and 90% between DMD- subgroups. Current findings demonstrate structural network-based characterization of abnormalities in DMD, especially prominent in Dp140-. Our observations suggest that participants with Dp140 + have relatively intact connectivity while Dp140- show widespread connectivity alterations at global, nodal, and edge levels. This study provides valuable insights supporting the genotype-phenotype correlation of brain-behavior involvement in DMD children.

The validity of abbreviated forms of the National Adult Reading Test and Spot-the-Word 2 for estimating full-scale IQ

ABSTRACT In this study, we validate an earlier proposal for an abridged 17-item National Adult Reading Test (NART) by comparing its performance in estimating full-scale IQ against both the full test and the Spot-the-Word 2 (STW-2) test in a new cohort. We also compare the performance of the 17-item NART to two previous attempts to shorten this test, the Mini-NART and the Short NART. Findings include that NART 17 is numerically stronger and statistically equivalent to the other short variants, the full 50-word NART, and STW-2. Unlike the Short NART, the 17-item NART is usable for participants of all ability levels rather than only those with low reading ability, while offering equally precise premorbid estimates. We also compute that two-thirds of STW-2 is ostensibly redundant for full-scale IQ estimation and we, therefore, propose that, subject to additional verification in an independent sample, an abridged version of this test may also benefit clinical practice.

Critical windows of fluoride neurotoxicity in Canadian children

BackgroundFluoride has been associated with IQ deficits during early brain development, but the period in which children are most sensitive is unknown. ObjectiveWe assessed effects of fluoride on IQ scores across prenatal and postnatal exposure windows. MethodsWe used repeated exposures from 596 mother-child pairs in the Maternal-Infant Research on Environmental Chemicals pregnancy and birth cohort. Fluoride was measured in urine (mg/L) collected from women during pregnancy and in their children between 1.9 and 4.4 years; urinary fluoride was adjusted for specific gravity. We estimated infant fluoride exposure (mg/day) using water fluoride concentration and duration of formula-feeding over the first year of life. Intelligence was assessed at 3–4 years using the Wechsler Preschool and Primary Scale of Intelligence-III. We used generalized estimating equations to examine the associations between fluoride exposures and IQ, adjusting for covariates. We report results based on standardized exposures given their varying units of measurement. ResultsThe association between fluoride and performance IQ (PIQ) significantly differed across prenatal, infancy, and childhood exposure windows collapsing across child sex (p = .001). The strongest association between fluoride and PIQ was during the prenatal window, B = −2.36, 95% CI: −3.63, −1.08; the association was also significant during infancy, B = −2.11, 95% CI: −3.45, −0.76, but weaker in childhood, B = −1.51, 95% CI: −2.90, −0.12. Within sex, the association between fluoride and PIQ significantly differed across the three exposure windows (boys: p = .01; girls: p = .01); among boys, the strongest association was during the prenatal window, B = −3.01, 95% CI: −4.60, −1.42, whereas among girls, the strongest association was during infancy, B = −2.71, 95% CI: −4.59, −0.83. Full-scale IQ estimates were weaker than PIQ estimates for every window. Fluoride was not significantly associated with Verbal IQ across any exposure window. ConclusionAssociations between fluoride exposure and PIQ differed based on timing of exposure. The prenatal window may be critical for boys, whereas infancy may be a critical window for girls.