Lower Verbal IQ Research Articles

The influence of working memory on reading growth in subgroups of children with reading disabilities

This 3-year longitudinal study determined whether (a) subgroups of children with reading disabilities (RD) (children with RD only, children with both reading and arithmetic deficits, and low verbal IQ readers) and skilled readers varied in working memory (WM) and short-term memory (STM) growth and (b) whether growth in an executive system and/or a phonological storage system mediated growth in reading performance. A battery of memory and reading measures was administered to 84 children (11–17 years of age) across three testing waves spaced 1 year apart. The results showed that skilled readers yielded higher WM growth estimates than did the RD groups. No significant differentiation among subgroups of children with RD on growth measures emerged. Hierarchical linear modeling showed that WM (controlled attention), rather than STM (phonological loop), was related to growth in reading comprehension and reading fluency. The results support the notion that deficient growth in the executive component of WM underlies RD.

Verbal and memory skills in males with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a progressive pediatric disorder that affects both muscle and brain. Children with DMD have mean IQ scores that are about one standard deviation lower than population means, with lower Verbal IQ than Performance IQ scores. For the present study, verbal skills and verbal memory skills were examined in males with DMD with the Clinical Evaluation of Language Fundamentals, 3rd edition, and the California Verbal Learning Test for Children. Performance of 50 males with DMD (age range 6-14 y, mean 9 y 4 mo [SD 2 y 1 mo]) was compared to normative values. Two subsets of the probands were also compared with two comparison groups: unaffected siblings (n=24; DMD group age range 6-12 y, mean 9 y 1 mo [SD 1 y 8 mo]; sibling age range 6-15 y, mean 9 y 11 mo [SD 2 y 4 mo]) and males with cerebral palsy (CP); (n=23; DMD group age range 6-9 y, mean 7 y 8 mo [SD 1 y 2 mo]; CP age range 6-8 y, mean 6 y 8 mo [SD 0 y 8 mo]). Results demonstrated that although males with DMD performed slightly more poorly than normative values, they performed comparably to the controls on most measures. Consistent deficits were observed only on tests requiring immediate repetition for verbal material (Recalling Sentences, and Concepts and Directions). On other language tasks, including tests of understanding and use of grammar, and understanding of semantic relationships, the males with DMD performed well. Moreover, the males with DMD performed well on multiple indices of verbal recall, and there was no evidence of declarative memory deficits. DMD is a single-gene disorder that is selectively associated with decreased verbal span capacity, but not impaired recall.

Tensor magnetic resonance imaging in a case of mild traumatic brain injury with lowered verbal intelligence quotient

We report the case of a 31-year-old man who had mild traumatic brain injury as a result of an accident at the age of 24 years. Seven years after the trauma, at the age of 31 years, he had a lower verbal intelligence quotient than performance intelligence quotient by the Wechsler Adult Intelligence Scale - Revised, and frontal lobe dysfunction, for example, difficulty in maintaining or changing the set as revealed by the Wisconsin Card Sorting Test Keio Version. Conventional brain magnetic resonance imaging had not shown any abnormalities. Abnormal brain areas were detected on magnetic resonance diffusion tensor imaging. On tractography, some fibres from the corpus callosum towards the frontal cortex were noted to be lacking in the left hemisphere compared with the right. The tractography results may explain the patient's lowered verbal intelligence quotient and focal left frontal lobe dysfunction. Diffusion tensor imaging is therefore helpful in detecting lesions in mild traumatic brain injury with diffuse axonal injury.

The Role of Verbal Competence and Multiple Risk on the Internalizing Behavior Problems of Costa Rican Youth

This longitudinal study examined internalizing behavior problems (anxiety/depression) in early adolescence in relation to adversity in early childhood and child verbal competence. We hypothesized that verbal competence would act as a protective factor in the face of early adversity, that is, high verbal IQ would predict relatively lower internalizing problems in early adolescence primarily for those children who experienced the greatest adversity. The sample was based on 191 Costa Rican children and their mothers, who were recruited in infancy from an urban community and assessed again at 5 and 11-14 years. Families were generally lower-middle to working class. A total of 165 children (94 boys) participated in the early adolescent follow-up (mean age = 12.3 years). Internalizing problems were based on maternal report (Spanish Child Behavior Checklist). Our cumulative risk index (CRI)_of adversity in early childhood consisted of home environment quality (HOME score), socioeconomic status, maternal depressed mood (CESD), and maternal IQ. Controlling for the effects of age, gender, internalizing problems at 5 years, and verbal IQ at 5 years, there was a significant interaction between early adversity and verbal IQ at age 11-14 years in predicting internalizing problems in early adolescence. Youth with high verbal IQ had comparable levels of internalizing problems regardless of high or low adversity in early childhood. In contrast, youth with low verbal IQ received higher internalizing problem ratings if they experienced high adversity early in life. The results raise the possibility that interventions to improve verbal competence might help lower the risk of internalizing problems in the face of early adversity.

Predicting Memory Decline Following Epilepsy Surgery: A Multivariate Approach

While some patients experience a decline in memory function following an anterior temporal lobe resection, there is considerable individual variation in the extent, nature, and direction of postoperative memory change. Patients with surgically remediable temporal lobe epilepsy differ in etiology, the extent and type of underlying pathology, and on demographic and epilepsy-related variables, all of which may have an impact on their pre- and postoperative neuropsychological functioning. This study examined the relationship between these variables and postoperative memory decline. Logistic regression was used to examine the effects of age, laterality of surgery, age of onset of epilepsy, underlying pathology and preoperative level of memory function on postoperative verbal learning in 288 patients who had undergone an anterior temporal lobe resection. One hundred twenty-five patients underwent a right temporal lobe resection (RTL), 163 patients underwent a left temporal lobe resection (LTL). In the group as a whole, 25% of the patients demonstrated a significant postoperative deterioration in verbal learning. Postoperative deterioration in verbal learning was significantly associated with higher levels of preoperative function in both the RTL and LTL groups. Older age at the time of the operation and a lower verbal IQ were additional significant predictors for the RTL group. The presence of cortical dysgenesis was a significant predictor of postoperative decline in the LTL group. The logistic regression models accurately identified 3/4 of those who experienced a postoperative decline in memory, using a cutoff of 0.25 or above to identify high risk. Our analyses suggest that the majority of patients with a high risk of significant postoperative memory decline can be reliably identified preoperatively. These models are valuable tools helping patients make an informed decision regarding surgery.

Do Different Components of Working Memory Underlie Different Subgroups of Reading Disabilities?

The purpose of this study was to determine the components of working memory (WM) that underlie less skilled readers' comprehension and word recognition difficulties. Performance of 3 less skilled reading subgroups---children with reading disabilities (RD) in both word recognition and comprehension; children with comprehension deficits only; and children with low verbal IQ, word recognition, and comprehension (poor readers)--was compared to that of skilled readers on WM, short-term memory (STM), processing speed, executive, and phonological processing measures. Ability group comparisons showed that (a) skilled readers outperformed all less skilled readers on measures of WM, updating, and processing speed; (b) children with comprehension deficits only outperformed children with RD on measures of WM, STM, phonological processing, and processing speed; and (c) children with RD outperformed poor readers on WM and phonological processing measures. A hierarchical regression analysis showed that (a) subgroup differences on WM tasks among less skilled readers were moderated by a storage system not specific to phonological skills, and (b) STM and updating contributed significant variance to WM beyond what was contributed by reading group classification. The latter finding suggested that some differences in storage and executive processing emerged between skilled and less skilled readers that were not specific to reading.

The intellectual performance of traumatized children and adolescents with or without posttraumatic stress disorder.

This study compared the Wechsler Intelligence Scale for Children-III (WISC-III) scores of traumatized youth with posttraumatic stress disorder (PTSD) to the scores of trauma-exposed and nonexposed comparison groups without PTSD. All groups were free of additional major childhood psychiatric disorders. The PTSD group scored significantly lower than the comparison groups on verbal subtests, but not on performance subtests. The scores of the trauma-exposed PTSD negatives and nontrauma exposed controls were not significantly different. Accordingly, PTSD and not a history of trauma exposure in the absence of PTSD was associated with lower verbal IQ.

Tic Symptom Profiles in Subjects with Tourette Syndrome from two Genetically Isolated Populations

Tourette Syndrome (TS) has a complex etiology and wide variability in phenotypic expression. Identifying underlying symptom patterns may be useful for etiological and outcome studies of TS. Lifetime tic and related symptom data were collected between 1996 and 2001 in 121 TS subjects from the Central Valley of Costa Rica and 133 TS subjects from the Ashkenazi Jewish (AS) population in the US. Subjects were grouped by tic symptoms using an agglomerative hierarchical cluster analysis. Cluster membership was tested for association with available ancillary information (age of onset, tic severity, comorbid disorders, medication treatment and family history). Cluster analysis identified two distinct groups in each sample, those with predominantly simple tics (cluster 1), and those with multiple complex tics (cluster 2). Membership in cluster 2 was correlated with increased tic severity, global impairment, medication treatment, and presence of comorbid obsessive-compulsive symptoms in both samples, and with family history of tics, lower verbal IQ, earlier age of onset, and comorbid obsessive-compulsive disorder and attention-deficit/hyperactivity disorder in the AS sample. This study provides evidence for consistent and reproducible symptom profiles in two independent TS study samples. These findings have implications for etiological studies of TS.

Characteristics of the broader phenotype in autism: A study of siblings using the children's communication checklist‐2

Non-autistic relatives of people with autistic disorder have an increased risk of social and communicative difficulties: this is known as the "broad phenotype." Better methods for characterizing the broad phenotype are needed to facilitate identification of risk genes for autism. 29 siblings of 20 children with autistic disorder, 13 siblings of 9 children with PDDNOS, and 46 typically developing control children from 26 families were assessed by parental report using the Children's Communication Checklist-2 (CCC-2). Groups were matched on age and IQ and siblings with autism were excluded. Group mean scores on the CCC-2 differed on only one subscale, syntax. However, siblings of children with autism or PDDNOS were over-represented in the tails of the distributions of several scales, and 10 (24%) scored more than 2 SD below the control mean on a total score based on all 10 subscales. Only two of these 10 children scored above threshold on one or more scales of the Autism Diagnostic Interview-Revised (ADI-R). Children with abnormal scores on the CCC-2 total were characterized by low-verbal IQ and their fathers tended to score high on the social and communication scales of the Autism Quotient, a measure of the broad phenotype in adults. The CCC-2 shows promise as a quick screening device for the broad phenotype in non-autistic siblings of children with autism.

Valproic Acid in Epilepsy

Valproic acid (sodium valproate) is widely used as a first-line antiepileptic agent. As with many antiepileptic drugs, there are a number of consequences associated with the use of valproic acid in women of child-bearing potential. Most pregnancies have a favourable outcome in women with epilepsy, and these women should not be discouraged from becoming pregnant. Unlike many other antiepileptic drugs, valproic acid has no significant pharmacokinetic interactions with the steroid hormones used in oral contraceptives. During pregnancy, the major risks to mother and child result from loss of seizure control on the one hand, and an elevated risk of major congenital malformations due to antiepileptic drug treatment on the other. In particular, an elevated risk of major congenital malformations associated with valproic acid use has been a consistent finding in studies of patient registries and several large case series. In addition, developmental delay, characterised by low verbal IQ, has also been reported in children exposed to valproic acid in utero, although the relative risk is not precisely known. For these reasons, pregnancies in women being treated with valproic acid need to be planned, and the benefit-risk ratios associated with continuing valproic acid or changing treatment need to be discussed with the patient. When treatment with valproic acid is the most appropriate treatment to achieve optimal seizure control, a number of measures can be implemented to minimise risk to the fetus. These include the use of the lowest possible effective dose of valproic acid in monotherapy (ideally <1000 mg/day), appropriate folic acid supplementation and close antenatal monitoring. Regular counselling is a prerequisite for informed planning of pregnancies and optimisation of the probability of a healthy outcome. Future research on valproic acid and pregnancy should involve risk assessment in large, population-based prospective studies.

Verbal Intelligence and Criminal Offending Among Men With Schizophrenia

There are well-documented associations between low verbal IQ and criminal offending and between low verbal IQ and early-onset persistent offending among males in the general population. This study was designed to test whether similar associations could be observed in a sample of 219 men with schizophrenia and schizoaffective disorder. The participants were recruited at discharge from forensic and general psychiatric hospitals in four sites in Canada, Finland, Germany and Sweden. In the weeks preceding discharge, information was collected from participants, family members, staff, and official records. The results demonstrated that low verbal IQ was not associated with the risk of criminal offending, nor with the numbers of offences, but with the age at first non-violent offence. Low verbal IQ was associated with lengthy stays in hospital that may have limited further criminal offending.

Olfactory deficits, cognition and negative symptoms in early onset psychosis

BackgroundSmell identification deficits (SID) are common in adult schizophrenia, where they are associated with negative symptoms and lower intelligence. However, smell identification has not been examined in adolescents with early onset psychosis, wherein diagnosis is often obscure, and there are few prognostic predictors. MethodWe examined smell identification, diagnosis, neuropsychological performance and symptoms in 26 well characterized adolescents with early onset psychosis, age 11–17 years. ResultsSID existed in the sample and were more common in patients with schizophrenia and psychotic depression than in patients with psychosis NOS and bipolar disorder. As in adults, SID were significantly associated with greater negative symptoms and lower verbal IQ. However, the associations of verbal IQ (and other verbal tasks) to smell identification in this pediatric sample were explained by the relation of both of these types of variables to negative symptoms. ConclusionsSID existed across this sample of youths with psychotic disorder, and were specifically related to typical characteristics of schizophrenia, such as negative symptoms and lower intelligence, but not to features of bipolar disorder, such as grandiosity. SID is a characteristic of early onset psychosis that may be useful for prognostic purposes.

Do adolescents with autistic spectrum disorders adhere to social conventions in virtual environments?

The potential for using virtual environments (VEs) in educational contexts for people with autistic spectrum disorders (ASDs) has been recognized. However, very little is known about how people with ASDs interpret and understand VEs. This study aimed to investigate this directly with a group of 12 adolescents with ASDs, each individually matched with comparison participants. Participants were presented with VEs to assess whether they adhered to particular social conventions, such as not walking across grass and flowerbeds en route to a café, or not walking between two people (ostensibly involved in conversation) en route to the bar. Whilst a significant minority of the ASD group adhered to the social conventions, others displayed substantial 'off-task' behaviour and a limited understanding of the VE. It is suggested that some individuals with an ASD, low verbal IQ and weak executive ability require the most support to complete tasks successfully in the VE.

Critical risk factors for intellectual impairment in children with posterior fossa tumors: the role of cerebellar damage

Intellectual impairment is a major concern after treatment of malignant posterior fossa tumors in children. The effects of age at diagnosis and radiotherapy have been widely documented. Little is known, however, about perioperative factors, especially neurological damage to the cerebellum, the role of which in cognition and learning has been recently indicated. The authors studied the effects in 76 children treated for a malignant posterior fossa tumor in a cross-sectional study. Two thirds of the tumors were medulloblastoma. Neuropsychological evaluation was performed at least 6 months after the end of treatment, and findings were correlated with clinical risk factors for intellectual impairment. The mean verbal intelligence quotient (VIQ) score was 87 +/- 19 (+/- standard deviation) and the mean performance IQ (PIQ) score was 76 +/- 17.5. A single neuropsychological test measuring hand skills (the Purdue Pegboard) was the strongest predictor of low IQ scores including items testing higher cognitive functions. A low VIQ was associated with impaired hand skills (p < 0.0001) and the presence of preoperative hydrocephalus (p = 0.02), whereas a low PIQ was associated with impaired hand skills (p < 0.0001) and incision of the vermis (p = 0.02). Impaired hand skills were associated with postoperative cerebellar mutism, oculomotor deficits, cerebellar syndrome, and therapeutic requirements. When treatment schedules are adapted to risk of disease and age, surgery-related risk factors then become critical for predicting intellectual impairment. Children with cerebellar damage are particularly at risk for long-term neuropsychological dysfunction and require active rehabilitation measures. Reducing surgery-related morbidity should be the next goal to reduce posterior fossa surgery-specific deficits.

The longer term outcome of children born to mothers with epilepsy

Objectives: To determine the prevalence of cognitive delay and possible associated dysmorphic features in children exposed to antiepileptic drugs (AEDs) in utero. Design: Retrospective study of children born to mothers...

Length of stay after infant heart surgery is related to cognitive outcome at age 8 years

Objective To test the hypothesis that postoperative length of stay (LOS) after infant heart surgery might be an easily measured surrogate marker for various events that culminate in later adverse cognitive outcome.Methods Among 160 eligible patients with D-transposition of the great arteries undergoing reparative surgery in infancy, 155 (97%) were reevaluated at age 8 years with IQ and achievement testing. We explored whether LOS quartiles were associated with these outcomes when adjusting for perioperative and sociodemographic variables.Results Longer cardiac intensive care unit (CICU) LOS quartiles were associated at age 8 years with lower full-scale IQ (P=.02), lower verbal IQ (P=.02), and with tendencies toward lower performance IQ (P=.08) and math achievement (P=.08) in adjusted models. Compared with patients in the first quartile of CICU LOS, those in the fourth quartile had mean scores for full-scale IQ that were lower by 7.2 points (P=.01); verbal IQ, 7.3 points (P=.02); performance IQ, 5.8 points (P=.05); and math achievement, 6.0 points (P=.07). Analyses on hospital LOS quartile were similar.Conclusions Longer postoperative LOS is associated with worse later cognitive function, even when adjusted for perioperative events, perfusion times, and sociodemographic variables. Further research is necessary to determine the mechanisms underlying this relation.

Verbal Intelligence and Sleep Disorders in Children with ADHD

In the present study, WISC-III Verbal IQ and sleep disorders in children with Attention Deficit Hyperactivity Disorder (ADHD) and controls who were matched for age and sex were assessed. 18 children with ADHD, 14 boys and 4 girls, and 18 controls, 14 boys and 4 girls, participated. Polysomnographs were performed for all ADHD children during their night sleep. The Greek version of WISC-III was used to evaluate Verbal IQ. Analysis of the polysomnographs showed that the quality of night sleep of the children with ADHD was very poor, including apneas, low desaturation rates, and awakenings in combination with limb activity and snoring. This agreed with their low Verbal IQ, which was up to 20 points lower than the controls' Verbal IQ. Sleep disorders in ADHD children could contribute to lower Verbal IQ.

Cognitive performance in a low birth weight cohort at 5 and 11 years of age

The objective of this study was to evaluate cognitive functions, changes over time, and prenatal, perinatal, and neonatal predictors in low birth weight children. A cohort of 130 low birth weight children was compared with 131 control children. A neuropsychologic test battery including subtests from the Wechsler Intelligence Scale for Children-Revised and the Illinois Test of Psycholinguistic Abilities, Knox Cube Test, Grooved Pegboard Test, Finger, and Foot Tapping was used. School performance was assessed using the Child Behavior Check List. Low birth weight children were comparable with control children in areas of verbal and visuo-spatial function, distractibility, and motor tempo, when parental factors were controlled for. An apparent association between breast milk feeding and child intelligence quotient was rendered insignificant when confounding parental factors were controlled for. None of the other identifiable prenatal, perinatal, or neonatal predictors were significantly related to cognitive outcome or school problems at 11 years of age. No differences were found in cognitive functions between those weighing less than 1500 g and 1500-2000 g. Motor problems and low verbal intelligence quotient at 5 years of age in the low birth weight children (previously published data) each doubled the risk of presenting a school problem at 11 years of age. Our findings are encouraging for low birth weight children regarding testable cognitive consequences and less encouraging regarding ability of cognitive test to identify school problems.

Gender differences in reactive and proactive aggression.

The purpose of our investigation was to study gender differences in proactive and reactive aggression in a sample of 323 clinically referred children and adolescents (68 females and 255 males). Proactive aggression and reactive aggression were assessed using the Proactive/Reactive Aggression Scale. Demographic, historical, family, diagnostic, and treatment variables were entered into stepwise regression analyses to determine correlates of proactive and reactive aggression in males and females. Results reveal high rates of aggression in both males and females in the sample. Self reported drug use, expressed hostility, and experiences of maladaptive parenting were correlated with proactive aggression for both genders. Hyperactive/impulsive behaviors were correlated with male reactive aggression. An early age of traumatic stress and a low verbal IQ were correlated with female proactive aggression. Gender differences in correlates of proactive and reactive aggression may provide possible targets for research, prevention, and treatment efforts focused on reducing maladaptive aggression in clinically referred youth.

VERBAL INTELLIGENCE AND SLEEP DISORDERS IN CHILDREN WITH ADHD

In the present study, WISC-III Verbal IQ and sleep disorders in children with Attention Deficit Hyperactivity Disorder (ADHD) and controls who were matched for age and sex were assessed. 18 children with ADHD, 14 boys and 4 girls, and 18 controls, 14 boys and 4 girls, participated. Polysomnographs were performed for all ADHD children during their night sleep. The Greek version of WISC-III was used to evaluate Verbal IQ. Analysis of the polysomnographs showed that the quality of night sleep of the children with ADHD was very poor, including apneas, low desaturation rates, and awakenings in combination with limb activity and snoring. This agreed with their low Verbal IQ, which was up to 20 points lower than the controls' Verbal IQ. Sleep disorders in ADHD children could contribute to lower Verbal IQ.