Low IQ Groups Research Articles

Parental psychological control and child anxiety in a multiethnic sample of youth with autism spectrum disorder

BackgroundThis study examined the relation between parental psychological control (PC) and child anxiety in a sample of white non-Latin American (WNLA), Hispanic/Latin American (H/LA), and African American (AA) youth with autism spectrum disorder (ASD). It was hypothesized that for youth with higher IQs, PC would be positively associated with anxiety for the WNLA group, but not for the H/LA and AA groups. MethodsArchival data from 603 youth diagnosed with ASD were used to test hypotheses. PC was measured by summing responses to items on an intake form indicative of parenting practices reflecting PC. ResultsResults of a hierarchical regression predicting child anxiety indicated a significant three-way interaction between PC, ethnicity (WNLA vs AA), and IQ. The graph of the interaction and tests of slopes showed that in the high IQ group, PC was positively associated with anxiety for the WNLA group and negatively associated with anxiety for the AA group. In the low IQ group, PC was positively associated with anxiety for the WNLA and AA groups. ConclusionsThese findings indicate that cultural variations in the relation between PC and child anxiety found in typically developing youth are applicable to youth with ASD but only for those with higher IQs.

Nonverbal Intelligence Does Matter for the Perception of Second Language Sounds

Although there has been considerable research on the interplay between intelligence and second language (L2) learning, research focusing on the intelligence and L2 speech perception link is limited. The present study aims to fill this gap. The native language of the participants was Cypriot Greek and they spoke English as an L2. The participants completed a forced-choice psychoacoustic test in which they discriminated L2 sound contrasts and a nonverbal intelligence test which measured their nonverbal intelligence capacities. They were divided into two groups according to their performance in the intelligence test, namely, a low IQ and a high IQ group. The results showed that the high IQ group discriminated the majority of the L2 contrasts better than the low IQ group. In addition, the degree of perceived difficulty for most L2 contrasts differed between the two groups. It is concluded that nonverbal intelligence is associated with the discrimination of L2 sounds. This can be explained by the possibility that either intelligence triggers the more efficient functioning of other domains, such as information processing and attention, leading to increased speech perception skills, or that it directly affects the categorization of speech sounds resulting in the development of more robust L2 categories.

Theory of mind in schizophrenia: a comparison of subgroups with low and high IQ

Background Social cognitive impairment is common in schizophrenia, but it is unclear if it is present in individuals with high IQ. This study compared theory of mind (ToM) in schizophrenia participants with low or high IQ to healthy controls. Methods One hundred and nineteen participants (71 healthy controls, 17 high IQ (IQ ≥115), and 31 low IQ (IQ ≤95) schizophrenia participants) were assessed with the Movie for the Assessment of Social Cognition, providing scores for total, cognitive, and affective ToM, along with overmentalizing, undermentalizing, and no-mentalizing errors. IQ was measured with Wechsler Abbreviated Scale of Intelligence; clinical symptoms with the Positive and Negative Syndrome Scale. Results Healthy controls performed better than the low IQ schizophrenia group for all ToM scores, and better than the high IQ schizophrenia group for the total score and under- and no-mentalizing errors. The high IQ group made fewer overmentalizing errors and had better total and cognitive ToM than the low IQ group. Their number of overmentalizing errors was indistinguishable from healthy controls. Conclusion Global ToM impairment was present in the low IQ schizophrenia group. Overmentalizing was not present in the high IQ group and appears related to lower IQ. Intact higher-level reasoning may prevent the high IQ group from making overmentalizing errors, through self-monitoring or inhibition. We propose that high IQ patients are chiefly impaired in lower-level ToM, whereas low IQ patients also have impaired higher-level ToM. Conceivably, this specific impairment could help explain the lower functioning reported in persons with intact IQ.

The Effect of Teaching Methods (Lecturing, Reading, Cooperative Learning, and Skill Training) and the Level of Intelligence on the Outcomes of Learning Arabic in High School/تأثير طرق التعليم (المحاضرة و القراءة و التعليم التعاوني و تدريب المهارة) ومستوى

This study aims Knowing the Interaction between teaching methodology and intelligence on learning achievement in Arabic at MAPK MAN 1 Surakarta year lesson 2019/2020. This research applied quantitative. Conducted at MAPK MAN 1 Surakarta from january-february 2020. While the sample is class XI PK. The approach used in this study is a quantitative approach using experimental methods. collection techniques using Observation, Test and Documentation. Analysis techniques using the normality test, homogeneity test, and hypothesis testing. The conclusion of this reasearch is the influence of teaching method (Lecture, Recitation, and Grup in Work, Skill Training) and the level of Intellegence on Arabic learning Achievement in MAPK MAN 1 Surakarta. There were significant differences in Arabic learning using the lecture and recitation methods and students taught using group work methods and skills training. from the calculated r value greater than r table, namely rh = 0.49 0.44 = rt, There was a difference in the learning to students with low IQ or students in 1` lower IQ group. the calculated r value greater than the table, namely: rh = 0.78 0.44 = rt, The method of teaching group work and skills training can significantly improve students' learning in the experimental class when compared to the control group. This can be seen from the difference in the average value achieved by the two groups where the experimental group is greater than the control group, namely: 96 94.

Impact of IQ on the diagnostic yield of chromosomal microarray in a community sample of adults with schizophrenia

BackgroundSchizophrenia is a severe psychiatric disorder associated with IQ deficits. Rare copy number variations (CNVs) have been established to play an important role in the etiology of schizophrenia. Several of the large rare CNVs associated with schizophrenia have been shown to negatively affect IQ in population-based controls where no major neuropsychiatric disorder is reported. The aim of this study was to examine the diagnostic yield of microarray testing and the functional impact of genome-wide rare CNVs in a community ascertained cohort of adults with schizophrenia and low (< 85) or average (≥ 85) IQ.MethodsWe recruited 546 adults of European ancestry with schizophrenia from six community psychiatric clinics in Canada. Each individual was assigned to the low or average IQ group based on standardized tests and/or educational attainment. We used rigorous methods to detect genome-wide rare CNVs from high-resolution microarray data. We compared the burden of rare CNVs classified as pathogenic or as a variant of unknown significance (VUS) between each of the IQ groups and the genome-wide burden and functional impact of rare CNVs after excluding individuals with a pathogenic CNV.ResultsThere were 39/546 (7.1%; 95% confidence interval [CI] = 5.2–9.7%) schizophrenia participants with at least one pathogenic CNV detected, significantly more of whom were from the low IQ group (odds ratio [OR] = 5.01 [2.28–11.03], p = 0.0001). Secondary analyses revealed that individuals with schizophrenia and average IQ had the lowest yield of pathogenic CNVs (n = 9/325; 2.8%), followed by those with borderline intellectual functioning (n = 9/130; 6.9%), non-verbal learning disability (n = 6/29; 20.7%), and co-morbid intellectual disability (n = 15/62; 24.2%). There was no significant difference in the burden of rare CNVs classified as a VUS between any of the IQ subgroups. There was a significantly (p=0.002) increased burden of rare genic duplications in individuals with schizophrenia and low IQ that persisted after excluding individuals with a pathogenic CNV.ConclusionsUsing high-resolution microarrays we were able to demonstrate for the first time that the burden of pathogenic CNVs in schizophrenia differs significantly between IQ subgroups. The results of this study have implications for clinical practice and may help inform future rare variant studies of schizophrenia using next-generation sequencing technologies.

Bifactor model of WISC-IV: Applicability and measurement invariance in low and normal IQ groups.

This study examined the applicability and measurement invariance of the bifactor model of the 10 Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) core subtests in groups of children and adolescents (age range from 6 to 16 years) with low (IQ ≤79; N = 229; % male = 75.9) and normal (IQ ≥80; N = 816; % male = 75.0) IQ scores. Results supported this model in both groups, and there was good support for measurement invariance for this model across these groups. For all participants together, the omega hierarchical and explained common variance (ECV) values were high for the general factor and low to negligible for the specific factors. Together, the findings favor the use of the Full Scale IQ (FSIQ) scores of the WISC-IV, but not the subscale index scores. (PsycINFO Database Record

Investigating Discrepancies between Predicted and Observed Wechsler Adult Intelligence Scale‐Version IV Full‐Scale Intelligence Quotient Scores in a Non‐Clinical Sample

ObjectiveIn neuropsychological assessment estimates of how a client was performing prior to an injury is achieved by using instruments that have been developed to predict premorbid abilities, such as the National Adult Reading Test (NART), the re‐standardised NART (NART‐2), the Wechsler Test of Adult Reading (WTAR), and the Test of Premorbid Functioning (TOPF), and comparing these to scores from tests of current ability, such as the Wechsler Adult Intelligence Scale‐Fourth Edition (WAIS‐IV). These instruments have been criticised, however, due to concerns regarding the accuracy of their predictions.MethodThis study evaluated the ability of the NART, NART‐2, WTAR and TOPF to accurately estimate current full scale intelligence quotient (FSIQ) as measured by the WAIS‐IV in an unimpaired Australian sample.ResultsFor the sample as a whole, the NART significantly over‐estimated FSIQ, whilst the TOPF significantly underestimated FSIQ. In the low average IQ group, scores were over‐estimated by the NART‐2 and WTAR. In the average group, the predicted FSIQ scores produced by each measure were relatively accurate. In the high average group, NART was the best predictor of FSIQ, while the other tests all significantly underestimated IQ.ConclusionsIt was concluded that reading tests may not be the most accurate method for predicting IQ, and that other approaches which include demographic correction the should be further explored.

Supplemental Material for Bifactor Model of WISC-IV: Applicability and Measurement Invariance in Low and Normal IQ Groups

Supplemental Material for Bifactor Model of WISC-IV: Applicability and Measurement Invariance in Low and Normal IQ Groups

Impact of duration of untreated psychosis and premorbid intelligence on cognitive functioning in patients with first-episode schizophrenia

BackgroundThe neurotoxic hypothesis suggests that psychosis is toxic to the brain leading to clinical consequences. In this study, we hypothesized that a longer duration of untreated psychosis (DUP) in first episode schizophrenia (FES) patients is associated with poorer cognitive functioning, and that higher premorbid intelligence buffers against DUP-related cognitive impairment. MethodEighty-one FES patients completed a neuropsychological battery, the Brief Assessment of Cognition in Schizophrenia (BACS). Composite scores of the BACS, which were normalized to a matched healthy control of seventy-three subjects, were used as an index of general cognition. A median split using the Wide Range Achievement Test–Reading Test scores was used to divide the patients into low versus high premorbid IQ groups. Hierarchical linear regression was performed to examine predictors of general cognition, including DUP. ResultsLonger DUP was found to be a significant predictor of poorer general cognition. In addition, DUP predicted general cognition in the low premorbid IQ group but not in the high premorbid IQ group. ConclusionsOur findings demonstrate that longer DUP in FES patients is associated with worse cognitive scores, and that this association is more pronounced in a subgroup of patients who have lower premorbid intelligence. Our results suggest the importance of earlier identification and management of patients with low premorbid IQ, given that their cognition may be more vulnerable to the toxicity of psychosis.

Career outcomes of adolescents with below average IQ: Who succeeded against the odds?

The educational and vocational careers of adolescents with below average IQ were studied in a sample of Swedish adolescents (N=1326), born in 1955 and followed from early adolescence to midlife. Compared to those with average IQ, the level of education and occupational status achieved by those with below average IQ were, generally, considerably lower. This was the case, in particular, for female participants in the lowest IQ group. No significant relationships were found between parents' socioeconomic status and educational level, income, or occupational status in midlife for adolescents with low IQ (lowest 20%). When those with a successful educational or vocational career were compared to others on a number of competence factors, own educational aspirations stood out as the factor that differed most within each IQ group between those who succeeded and those who did not. The differences were largest for those of low IQ (effect sizes 0.4–1.6). These findings were consistent with results from multiple regression analyses, which, for instance, showed that, within the low IQ group and controlling for confounders, the only significant predictor of career outcomes was educational aspirations.

Poster #T201 BEHAVIOURAL AND FMRI EVIDENCE OF SEMANTIC CATEGORISATION DEFICITS IN SCHIZOPHRENIA

There are two inter-related categories of EEG measurement: 1, EEG currents or power and; 2, EEG network properties such as coherence and phase delays. The purpose of this study was to compare the ability of these two different categories of EEG measurement to predict performance on the Weschler Intelligence test (WISC-R).Resting eyes closed EEG was recorded from 19 scalp locations with a linked ears reference from 442 subjects aged 5–52 years. The Weschler Intelligence test was administered to the same subjects but not while the EEG was recorded. Subjects were divided into high IQ (≥120) and low IQ (≤90) groups. EEG variables at P<.05 were entered into a factor analysis and then the single highest loading variable on each factor was entered into a discriminant analysis where groups were high IQ vs. low.Q.Discriminant analysis of high vs. low IQ was 92.81–97.14% accurate. Discriminant scores of intermediate IQ subjects (i.e. 90<IQ<120) were intermediate between the high and low IQ groups. Linear regression predictions of IQ significantly correlated with the discriminant scores (r=0.818–0.825, P<10−6). The ranking of effect size was EEG phase>EEG coherence>EEG amplitude asymmetry>absolute power>relative power and power ratios. The strongest correlations to IQ were short EEG phase delays in the frontal lobes and long phase delays in the posterior cortical regions, reduced coherence and increased absolute power.The findings are consistent with increased neural efficiency and increased brain complexity as positively related to intelligence, and with frontal lobe synchronization of neural resources as a significant contributing factor to EEG and intelligence correlations.Quantitative EEG predictions of intelligence provide medium to strong effect size estimates of cognitive functioning while simultaneously revealing a deeper understanding of the neurophysiological substrates of intelligence.

B-44Protective Effects of Premorbid Cognitive Reserve on Neuropsychological Performance after Brain Injury

Objective: Research has found that cognitive reserve, as indicated by premorbid intelligence estimates, serves as a protective factor against cognitive decline in several neuropsychiatric conditions including schizophrenia, depression, and bipolar disorders. We investigated whether the phenomenon of cognitive reserve as a protective factor against neurocognitive dysfunction extends to traumatic brain injury (TBI), even with the occurrence of posttraumatic amnesia (PTA), a strong indicator of TBI severity. Method: Clinical records of 120 adults screening positive for TBI were analyzed. Neuropsychological measures included: Repeatable Battery for the Assessment of Neuropsychological Status, Grooved Pegboard, Trails, WAIS-IV Digit Span, Numbers and Letters Test, and Delis–Kaplan Verbal Fluency and Interference Tests. Predictors included PTA per structured clinical interview and premorbid intelligence as estimated by the Wechsler Test of Adult Reading and Shipley Vocabulary tests. Results: Occurrence of PTA was significantly associated with lower premorbid intelligence. Further analysis indicated an interaction effect of PTA and premorbid intelligence for several measures of attention, verbal fluency, and affect recognition (p < .05), such that in the lower IQ group, PTA was associated with lower scores on these neurocognitive measures. However, PTA was not associated with lower cognitive performances in the higher IQ group. Significant interactions were not found for measures of fine motor functions and processing speed. Conclusion: Present analysis indicates that premorbid intelligence likely does serve to protect neuropsychological functioning following TBI even with the occurrence of PTA. This expands the range in which this phenomenon of cognitive reserve has been demonstrated and highlights the importance of accessible education.

Exploring the Proposed DSM-5 Criteria in a Clinical Sample

The proposed DSM-5 criteria for Autism Spectrum Disorder (ASD) depart substantially from the previous DSM-IV criteria. In this file review study of 131 children aged 2-12, previously diagnosed with either Autistic Disorder or Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), 63% met the new DSM-5 ASD criteria, including 81% previously diagnosed with Autistic Disorder and only 17% of those with PDD-NOS. The proportion of children meeting DSM-5 differed by IQ grouping as well, with higher rates in lower IQ groups. Children who did meet criteria for ASD had significantly lower levels of cognitive and adaptive skills and greater autism severity but were similar in age. These findings raise concerns that the new DSM-5 criteria may miss a number of children who would currently receive a diagnosis.

Poster #181 PREDICTORS OF REAL-WORLD OUTCOMES IN SCHIZOPHRENIA PATIENTS, THEIR FAMILY MEMBERS AND CONTROL SUBJECTS

Spearman's law of diminishing returns posits that general intelligence, or simply g, exerts a lesser influence in high-IQ groups than in low-IQ groups. The present study examined this phenomenon across populations and time, using the standardizations of the WAIS, WAIS-R and WAIS-III. Average intercorrelations were compared across each of the standardization samples. Results indicate that a significant decline in the statistical power of Spearman's g has occurred on a secular level, over a 46-year period. The largest decline seems to have occurred between 1955 (date of publication of the WAIS) and 1981 (date of publication for the WAIS-R). Maximum likelihood analysis confirmed the initial findings. Possible explanations for the differentiation of cognitive abilities are offered.

ファンクショナル・リーチによる健常者及び知的障害者の身体平衡機能

This study was conducted to investigate the characteristics of the functional reach test (FRT) in persons with intellectual disabilities (ID). The subjects were 41 persons with ID (male, 26; female, 15) and 44 healthy persons (controls). The subjects with ID were classified into two groups according to their intelligence quotient (IQ): the high-IQ and low-IQ groups. FRT was measured in the original (no target) condition and target condition. In the target condition, a white wall (target) was set in front of the subject. The FRT scores of the original condition and target condition and the difference between these FRT scores (FRT difference) were calculated. In the original condition, the FRT score of the controls was higher than those of the two groups with ID, in which no further comparison was significant. In the target condition, the FRT score of the controls was higher than those of the two groups with ID; the score of the high-IQ group was higher than that of the low-IQ group. The FRT difference of the high-IQ group was higher than that of the low-IQ group, which in turn was higher than that of the controls. These results suggested that persons with ID demonstrate a lower FRT score than healthy persons although the score can be increased greatly by the target, especially for persons with mild or moderate ID.

Novel method for combined linkage and genome-wide association analysis finds evidence of distinct genetic architecture for two subtypes of autism

The Autism Genome Project has assembled two large datasets originally designed for linkage analysis and genome-wide association analysis, respectively: 1,069 multiplex families genotyped on the Affymetrix 10 K platform, and 1,129 autism trios genotyped on the Illumina 1 M platform. We set out to exploit this unique pair of resources by analyzing the combined data with a novel statistical method, based on the PPL statistical framework, simultaneously searching for linkage and association to loci involved in autism spectrum disorders (ASD). Our analysis also allowed for potential differences in genetic architecture for ASD in the presence or absence of lower IQ, an important clinical indicator of ASD subtypes. We found strong evidence of multiple linked loci; however, association evidence implicating specific genes was low even under the linkage peaks. Distinct loci were found in the lower IQ families, and these families showed stronger and more numerous linkage peaks, while the normal IQ group yielded the strongest association evidence. It appears that presence/absence of lower IQ (LIQ) demarcates more genetically homogeneous subgroups of ASD patients, with not just different sets of loci acting in the two groups, but possibly distinct genetic architecture between them, such that the LIQ group involves more major gene effects (amenable to linkage mapping), while the normal IQ group potentially involves more common alleles with lower penetrances. The possibility of distinct genetic architecture across subtypes of ASD has implications for further research and perhaps for research approaches to other complex disorders as well.

Brain Morphometry and Intelligence Quotient Measurements in Children With Sickle Cell Disease

To verify the hypothesis that volume of regional gray matter accounts substantially for variability in intelligence quotient (IQ) score among children with sickle cell disease, who have no magnetic resonance visible infarcts. We studied 31 children with sickle cell disease, homozygous for hemoglobin S, with no history of stroke, no magnetic resonance signal-intensity abnormality, and transcranial Doppler velocities <170 cm/sec, with a T1-weighted magnetic resonance sequence and the Kaufman Brief Intelligence Test. On the basis of Kaufman Brief Intelligence Test, we classified these children into 2 groups: high and low IQ based on a median split. We then used an automated and novel Bayesian voxel-based morphometry technique, called Graphical-Model-Based Multivariate Analysis (GAMMA), to assess the probabilistic association between IQ score and regional gray matter volume. GAMMA found 1 region linking low IQ with smaller cortical gray matter volume. In comparison with the children in the high-IQ group, children in the low-IQ group had smaller regional gray matter volume in both frontal lobes, both temporal lobes, and both parietal lobes. In children with sickle cell disease, we found a linear association between IQ and regional gray matter volume. This finding suggests that some variance in intellectual ability in children with sickle cell disease is accounted for by regional variability of gray matter volume, which is independent of neuroradiological evidence of infarct.

IQ trajectory, cognitive reserve, and clinical outcome following a first episode of psychosis: a 3-year longitudinal study.

Comparison of current and estimated premorbid IQ in schizophrenia suggests that there are subgroups with low IQ, deteriorated IQ (DIQ), or preserved IQ and that this is established by psychosis onset. There are no controlled studies examining the trajectory of these IQ subgroups longitudinally or their relationship with clinical and social outcomes. Of 129 individuals with first-episode schizophrenia or schizoaffective disorder, 25% showed stable low IQ, 31% showed stable IQ in the average/high range, and 44% demonstrated intellectual deterioration by 10 points or more. Patients in the low and deteriorated groups were equally impaired on tests of memory and executive function compared with the preserved average/high-IQ group and controls and showed more negative and disorganization symptoms than the preserved average/high-IQ group. Sixty patients and 27 controls were assessed again 1 and 3 years later. There was no evidence that those with IQ deterioration at baseline continued on a declining cognitive trajectory or that those with preserved average/high IQ experienced subsequent IQ decline. The low IQ group showed no change in IQ, whereas both the DIQ and the preserved IQ groups improved. However, the rate of improvement of these 2 subgroups was no greater than that of the healthy controls, suggesting that this reflected practice effects. Both the low and the deteriorated groups had longer index admissions, more core negative symptoms, and worse occupational outcomes at 3 years. These data suggest that following psychosis onset, IQ is stable and that it is IQ at psychosis onset rather than premorbid IQ predicts a more severe illness.

Exploring the Diagnosis of “Gifted/LD”: Characterizing Postsecondary Students With Learning Disability Diagnoses at Different IQ Levels

Increasing numbers of students are being diagnosed as simultaneously gifted and having a learning disability, although the identification procedures and characteristics of these students are matters of continuing debate. In the present study, postsecondary students with learning disability diagnoses ( N = 357) were grouped according to their IQ scores, and the groups’ cognitive and achievement characteristics were explored, with special attention to the proportions of each group that would meet various objective criteria for learning disability diagnosis. Many students in each group failed to meet any of the criteria, although higher IQ students were more likely to meet most of the criteria. In addition, the higher IQ group exhibited higher achievement scores than did the lower IQ group, although the achievement gaps were much smaller than the IQ differences. Implications for the validity of the gifted/LD category as well as future research directions are discussed.

Characteristics of low IQ arsonists at psychiatric assessment

We conducted a retrospective study of arsonists referred for psychiatric assessment and found that 88/202 (43.6%) had an IQ of 85 or below. The low IQ group showed more evidence of childhood temperamental disturbance, and a later pattern of internal problems rather than external factors expressing themselves as fire-setting. This study highlights the likelihood of lifelong, temperamental problems being apparent in childhood, and being predictive and possibly causative of fire setting in people with a low IQ. Better understanding of the distinct characteristics of lower IQ arsonists is essential for improved prevention, treatment and management.