Performance IQ Scores Research Articles

Cognitive functioning in bilateral perisylvian polymicrogyria (BPP): clinical and radiological correlations

Bilateral perisylvian polymicrogyria (BPP) is a malformation of cortical development, frequently associated with severe dysarthria or anarthria. BPP patients are therefore often labeled as severely retarded, but a detailed neuropsychological profile has not been reported to date. In a series of 14 patients, we demonstrated that only a minority had extremely low intelligence, and that some aspects of cognitive function correlated with the extent of the cortical disorganization. Early age at seizure onset correlated positively with Performance IQ scores ( P < 0.05) and negatively with the extent of the lesion ( P < 0.01), reflecting that patients with more severe BPP are more likely to have early seizure onset, resulting in greater interference with ongoing cognitive development. Receptive and expressive language skills were found to be equally poor. Frontal lobe function and memory abilities were relatively well preserved, suggesting that the observed cognitive profiles were related, at least in part, to specific areas of cortical dysfunction and not only to global dysfunction.

International Collaborative Study of Intracytoplasmic Sperm Injection–Conceived, In Vitro Fertilization–Conceived, and Naturally Conceived 5-Year-Old Child Outcomes: Cognitive and Motor Assessments

International Collaborative Study of Intracytoplasmic Sperm Injection–Conceived, In Vitro Fertilization–Conceived, and Naturally Conceived 5-Year-Old Child Outcomes: Cognitive and Motor Assessments

Attentional and neurocognitive characteristics of high-risk offspring of parents with schizophrenia compared with DSM-IV attention deficit hyperactivity disorder children

Offspring of individuals with schizophrenia are at increased baseline risk for a range of early mental disorders. Studies investigating the premorbid characteristics of individuals with schizophrenia indicate that they suffer from social, behavioral, attentional and neurocognitive impairments, often resembling attention deficit hyperactivity disorder (ADHD). In this study, we compared the executive functioning and general intelligence among three groups: (i) children and adolescents with DSM-IV ADHD ( n=41), (ii) “high-risk” (HR) offspring of parents with DSM-IV schizophrenia, and (iii) normal comparison subjects ( n=35). Our results indicated that both HR and ADHD groups had lower Verbal IQ scores. ADHD cases had significantly lower percent correct and total errors in Wisconsin Cart Sorting Test when compared with normal comparison subjects. The HR cases also had lower Performance IQ scores as well as worse abstraction–flexibility and comprehension performance. The HR group was further stratified with (HR-A) and without (HR-NA) comorbid ADHD, and HR-A subjects were significantly noted to be more impaired on most tests. The overall worse performance of HR offspring was attributable to significantly lower performance among the HR-A youth. Further, our results suggested that the most profoundly impaired HR subjects were in fact children and adolescents who also met criteria for ADHD. Future studies with broader neuropsychological test batteries are necessary to investigate the differences and similarities between ADHD and the HR-A subgroup.

Cognitive Outcomes of Preschool Children With Prenatal Cocaine Exposure

Cocaine passes the placental and fetal brain barriers and directly affects the developing brain. The few prospective studies reported that examined the long-term cognitive effects of prenatal cocaine exposure have given inconsistent results. The present trial was a prospective, longitudinal, blind comparison cohort study assessing the effects of in utero cocaine exposure and the quality of caregiving on cognitive function at age 4 years. Of 415 consecutively enrolled infants, all from a high-risk population, 376 (190 cocaine-exposed and 186 unexposed) were available for evaluation at age 4 using the Wechsler Preschool and Primary Scales of Intelligence-Revised. Caregivers completed the Home Observation of the Environment (HOME)-Preschool version that assesses the quality of the caregiving environment. A majority of women were low-income blacks. Cocaine users were older than nonusers, had more children, and were less likely to have received prenatal care. They also were less likely to be married and to have completed high school, and they experienced more psychologic distress. Cocaine users also used alcohol, tobacco, and marijuana more often (and in greater amounts) than nonusers of cocaine. Exposed infants were of lower gestational age, birth weight, length, and head circumference than unexposed infants. They were likelier than unexposed infants to be preterm, small for gestational age, and in nonmaternal care. Controlling for covariables, prenatal cocaine exposure was not associated with lower full-scale IQ scores or summary verbal IQ stores at age 4 years. It did, however, predict small but significant deficits in visual-spatial skills, general knowledge, and arithmetic skills. Children exposed to cocaine before birth were less likely to achieve an IQ above the normative mean. Exposed children in nonrelative foster or adoptive care lived in more stimulating environments and had IQ scores comparable to those of unexposed children who were in biologic maternal or relative care. Their scores were higher than those of cocaine-exposed children in biologic maternal or relative care. The latter children had lower full-scale and performance IQ scores than did unexposed children. The quality of the caregiving environment was the strongest independent predictor of cognitive outcomes. These findings are in accord with those from other studies of preschool cocaine-exposed children that identified specific but not global IQ deficits. Cocaine-exposed children do better cognitively when living in a favorable home environment.

Cognitive Function Before and After Surgery in Patients With Unruptured Intracranial Aneurysm

This prospective study investigated whether surgery for unruptured intracranial aneurysms (UIAs) affects cognitive function and cerebral blood flow (CBF). Cognitive tests using the Wechsler Adult Intelligence Scale-Revised, Wechsler Memory Scale, Rey-Osterrieth Complex Figure test, and CBF measurements using single-photon emission computed tomography were performed before and after surgery for UIAs in 44 patients < or =70 years of age. Group-rate analysis showed the verbal intelligence quotient (IQ), performance IQ, full-scale IQ, and recall trial scores of the Rey-Osterrieth Complex Figure test all increased significantly after surgery, whereas the Wechsler Memory Scale and copy trial scores of the Rey-Osterrieth Complex Figure test were not significantly different. Event-rate analysis demonstrated that no patient showed impaired cognition. There was no significant difference between CBF before and after surgery. Surgical repair for UIAs does not impair cognition or CBF in patients without postoperative restrictions in lifestyle.

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.

Long term cognitive development in children with prolonged crying

Background: Long term studies of cognitive development and colic have not differentiated between typical colic and prolonged crying. Objective: To evaluate whether colic and excessive crying that persists beyond 3...

Investigation of Poor Academic Achievement in Children with Duchenne Muscular Dystrophy.

Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disorder that presents with progressive muscular weakness. It is caused by a mutation in a gene that results in the absence of specific products that normally localize to muscle cells and the central nervous system (CNS). The majority of affected individuals have IQs within the normal range, generally with lower verbal than performance IQ scores. Prior work has demonstrated selective deficits on tests of verbal span and immediate memory. For the current study, 26 boys with DMD (and normal intellectual function) and their unaffected siblings were evaluated. Paired comparisons demonstrated that the children with DMD had significantly poorer academic achievement scores than their siblings, even though their vocabulary levels and home and educational environments were comparable. Children with DMD also had more behavioral concerns, physical disabilities, and poorer verbal memory spans. Linear regression indicated that behavioral concerns, executive function, and physical disability did not contribute substantially to academic performance, whereas performance on verbal span did. DMD presents with a selective developmental aberration in verbal span that has wide-ranging consequences on learning skills.

Cognitive outcomes of preschool children with prenatal cocaine exposure.

Because of methodological limitations, the results of the few prospective studies assessing long-term cognitive effects of prenatal cocaine exposure are inconsistent. To assess effects of prenatal cocaine exposure and quality of caregiving environment on 4-year cognitive outcomes. Longitudinal, prospective, masked comparison cohort study from birth (September 1994-June 1996) to 4 years. Research laboratory of a US urban county teaching hospital. A total of 415 consecutively enrolled infants identified from a high-risk population screened for drug use through clinical interview, urine, and meconium screens. Ninety-three percent retention for surviving participants at 4 years of age resulted in 376 children (190 cocaine-exposed and 186 nonexposed). The Wechsler Preschool and Primary Scales of Intelligence-Revised. After control for covariates, prenatal cocaine exposure was not related to lower full-scale IQ (cocaine exposed [80.7] vs nonexposed [82.9]; P =.09) scores or summary verbal (cocaine exposed [79.9] vs nonexposed [81.9]; P =.11) or performance (cocaine exposed [85.5] vs nonexposed [87.5]; P =.18) IQ scores at age 4 years. However, prenatal cocaine exposure was related to small but significant deficits on several subscales (mean [SE]): visual-spatial skills (cocaine exposed [7.3 (0.22)] vs nonexposed [8.2 (0.22)]; P =.01), general knowledge (cocaine exposed [6.1 (0.18)] vs nonexposed [6.7 (0.17)]; P =.04), and arithmetic skills (cocaine exposed [6.2 (0.20)] vs nonexposed [6.8 (0.20)]; P =.05). Prenatal cocaine exposure was also associated with a lower likelihood of achievement of IQ above normative means (odds ratio, 0.26 [95% confidence interval, 0.10-0.65]; P =.004). The quality of the caregiving environment was the strongest independent predictor of outcomes. Cocaine-exposed children placed in nonrelative foster or adoptive care lived in homes with more stimulating environments and had caregivers with better vocabulary scores, and they attained full-scale and performance IQ scores (83 and 87, respectively) similar to nonexposed children in biological maternal or relative care (full-scale IQ, 82; performance IQ, 88) and higher than cocaine-exposed children in biological maternal or relative care (full-scale IQ, 79; performance IQ, 84). Prenatal cocaine exposure was not associated with lower full-scale, verbal, or performance IQ scores but was associated with an increased risk for specific cognitive impairments and lower likelihood of IQ above the normative mean at 4 years. A better home environment was associated with IQ scores for cocaine-exposed children that are similar to scores in nonexposed children.

Speech, Language, and Reading Skills After Early Cochlear Implantation

ObjectiveTo examine whether age at cochlear implantation or duration of implant use is associated with speech, language, and reading skills exhibited at age 8 to 9 years in children who underwent implantation by age 5 years.DesignPerformance outcomes in speech perception, speech production, language, and reading were examined in terms of the age at which children first received a cochlear implant (2, 3, or 4 years), the age they received an updated (Spectra) processor, and the duration of use of an implant and an updated processor.SettingData collection was conducted at summer research camps held over 4 consecutive years to maximize the number of children available at a specific age (8-9 years). Children were tested individually by experienced examiners, and their parents and therapists provided background and educational history information.ParticipantsA total of 181 children from 33 different states and 5 Canadian provinces who received a cochlear implant by age 5 years were tested. A subsample of 133 children with performance IQ scores of 80 or greater and onset of deafness at birth were selected for the age-at-implantation analysis. Another subsample of 39 children with deafness acquired by age 3 years was also examined.Outcome MeasuresA battery of tests of speech perception, speech production, language, and reading was administered to each child and reduced to a single factor score for each skill.ResultsCorrelation coefficients between age at implantation and duration of use did not reach significance for any of the outcome skills measured. Age at which the updated speech processor (Spectra) was fitted was significantly related to speech production outcome (earlier use of an updated processor was associated with greater speech intelligibility) but not to any other skill area. However, more of the children who underwent implantation at age 2 years (43%) achieved combined speech and language skills commensurate with their age-matched peers with normal hearing than did children who underwent implantation at age 4 years (16%). Furthermore, normal speech and language skills were documented in 80% of children who lost hearing after birth and who underwent implantation within a year of onset of deafness.ConclusionsFor children who receive a cochlear implant between the ages of 2 and 4 years, early cochlear implantation does not ensure better speech perception, speech production, language, or reading skills. However, greater speech and language proficiency may be expected from children who exhibit normal hearing for even a brief period after birth and receive a cochlear implant shortly after losing their hearing. Further research examining the benefits of cochlear implantation before age 2 years will help families and clinicians better understand the time-sensitive nature of the decision to conduct cochlear implant surgery.

Speech, language, and reading skills after early cochlear implantation.

To examine whether age at cochlear implantation or duration of implant use is associated with speech, language, and reading skills exhibited at age 8 to 9 years in children who underwent implantation by age 5 years. Performance outcomes in speech perception, speech production, language, and reading were examined in terms of the age at which children first received a cochlear implant (2, 3, or 4 years), the age they received an updated (Spectra) processor, and the duration of use of an implant and an updated processor. Data collection was conducted at summer research camps held over 4 consecutive years to maximize the number of children available at a specific age (8-9 years). Children were tested individually by experienced examiners, and their parents and therapists provided background and educational history information. A total of 181 children from 33 different states and 5 Canadian provinces who received a cochlear implant by age 5 years were tested. A subsample of 133 children with performance IQ scores of 80 or greater and onset of deafness at birth were selected for the age-at-implantation analysis. Another subsample of 39 children with deafness acquired by age 3 years was also examined. A battery of tests of speech perception, speech production, language, and reading was administered to each child and reduced to a single factor score for each skill. Correlation coefficients between age at implantation and duration of use did not reach significance for any of the outcome skills measured. Age at which the updated speech processor (Spectra) was fitted was significantly related to speech production outcome (earlier use of an updated processor was associated with greater speech intelligibility) but not to any other skill area. However, more of the children who underwent implantation at age 2 years (43%) achieved combined speech and language skills commensurate with their age-matched peers with normal hearing than did children who underwent implantation at age 4 years (16%). Furthermore, normal speech and language skills were documented in 80% of children who lost hearing after birth and who underwent implantation within a year of onset of deafness. For children who receive a cochlear implant between the ages of 2 and 4 years, early cochlear implantation does not ensure better speech perception, speech production, language, or reading skills. However, greater speech and language proficiency may be expected from children who exhibit normal hearing for even a brief period after birth and receive a cochlear implant shortly after losing their hearing. Further research examining the benefits of cochlear implantation before age 2 years will help families and clinicians better understand the time-sensitive nature of the decision to conduct cochlear implant surgery.

Global Approach to Multichannel Electroencephalogram Analysis for Diagnosis and Clinical Evaluation in Mild Alzheimer’s Disease

To establish an early diagnosis of Alzheimer’s disease (AD), we evaluated brain spatial dynamics and cognitive function in mild AD. Seventeen patients with the diagnosis of mild AD and 17 age-matched controls were examined for Ω (global complexity), Σ (total power) and Φ (generalized frequency) by 19-channel electroencephalography (EEG). As a result, the mild AD group showed significantly higher Ω values than the control group. The Φ values were highly correlated with the Mini-Mental State Examination scores and the full IQ and performance IQ scores of the Japanese Wechsler Adult Intelligence Scale Revised. These results indicate an increase in spatial complexity of the brain electric field in mild AD, as well as a close relationship between slowing of the global frequency of field changes and the cognitive decline in mild AD.

Subtemporal Amygdalohippocampectomy Prevents Verbal Memory Impairment in the Language-Dominant Hemisphere

Background: In this report, we show the operative and neuropsychological results for 20 patients with medically intractable nonlesional temporal lobe epilepsy treated surgically by subtemporal amygdalohippocampectomy whose mean postoperative follow-up period was more than 6 years. Methods: Pre- and postoperative Wechsler Adult Intelligence Scale-Revised (WAIS/-R) scores, including verbal intelligence quotient (VIQ), performance IQ (PIQ) and full-scale IQ (FIQ) scores, were determined in the 19 adults. The revised Wechsler Intelligent Scale for Children was used in a 9-year-old boy. The verbal paired associates learning test was performed pre- and postoperatively in 15 patients. These data were compared pre- and postoperatively in 10 patients in whom the language-dominant hemisphere side was operated on, and in 5 patients in whom the language-non-dominant side was operated on. Results: Seizure control was achieved in 80% of patients, with improvement into Engel categories I and II without definite permanent complications except for postoperative memory impairment in one patient. VIQ improved after 2 years, and PIQ and FIQ improved after both 2 months and 2 years postoperatively. Conclusion: There was no significant decline in the postoperative verbal memory scores in those patients whose medial temporal structure of the language-dominant side had been removed.

Apathy in schizophrenia: reduced frontal lobe volume and neuropsychological deficits.

Apathy is a common negative symptom in schizophrenia. The authors investigated neuropsychological performance and regional brain volumes in schizophrenia patients with high versus low levels of apathy. Schizophrenia patients with low apathy levels (N=18) and high apathy levels (N=20) and 12 healthy comparison subjects completed neuropsychological testing as well as magnetic resonance imaging scanning to obtain lobar volumes after total intracranial volume was controlled. The high apathy group scored lower than comparison subjects on rapid visuomotor sequencing and verbal learning/recall. The high apathy group had lower performance IQ scores than the low apathy and comparison groups. Only the high apathy group showed significantly reduced bilateral frontal lobe volumes relative to comparison subjects; both schizophrenia patient groups showed bilateral temporal lobe volume reductions. The present findings are consistent with studies in other disorders showing frontal lobe involvement in apathy.

Neurodevelopmental status at eight years in children with dextro-transposition of the great arteries: The Boston Circulatory Arrest Trial

Objectives Our goal was to determine which of the two major methods of vital organ support used in infant cardiac surgery, total circulatory arrest and low-flow cardiopulmonary bypass, results in better neurodevelopmental outcomes at school age. Methods In a single-center trial, infants with dextrotransposition of the great arteries underwent the arterial switch operation after random assignment to either total circulatory arrest or low-flow cardiopulmonary bypass. Developmental, neurologic, and speech outcomes were assessed at 8 years of age in 155 of 160 eligible children (97%). Results Treatment groups did not differ in terms of most outcomes, including neurologic status, Full-Scale or Performance IQ score, academic achievement, memory, problem solving, and visual-motor integration. Children assigned to total circulatory arrest performed worse on tests of motor function including manual dexterity with the nondominant hand ( P = .003), apraxia of speech ( P = .01), visual-motor tracking ( P = .01), and phonologic awareness ( P = .003). Assignment to low-flow cardiopulmonary bypass was associated with a more impulsive response style on a continuous performance test of vigilance ( P < .01) and worse behavior as rated by teachers ( P = .05). Although mean scores on most outcomes were within normal limits, neurodevelopmental status in the cohort as a whole was below expectation in many respects, including academic achievement, fine motor function, visual-spatial skills, working memory, hypothesis generating and testing, sustained attention, and higher-order language skills. Conclusions Use of total circulatory arrest to support vital organs during heart surgery in infancy is generally associated with greater functional deficits than is use of low-flow cardiopulmonary bypass, although both strategies are associated with increased risk of neurodevelopmental vulnerabilities.

Three factors of the comprehensive system for the Rorschach and their relationship to Wechsler IQ scores in an adolescent sample.

Principal axis factor analyses of the Rorschach Comprehensive System (CS) in a clinical sample of 152 adolescents yielded three clearly defined factors: Synthesized Complexity (defined by Zf, DQ+, and F%), Productivity (defined by R, D, and Dd), and Form Quality (defined by X+%, F+%, and X-%). Variables on the Synthesized Complexity and Form Quality factors were generally correlated with Wechsler Full Scale IQ, Verbal IQ, and Performance IQ scores. Overall, the factors in this adolescent sample replicated factors identified in earlier studies with adults. Implications for clinical practice are discussed.

Autism, primary pragmatic difficulties, and specific language impairment: can we distinguish them using psycholinguistic markers?

Three groups of children with communication disorders were examined using a series of psycholinguistic markers to explore whether the tasks could identify children with impairments other than specific language impairment (SLI), and to examine whether the different groups within this clinical population could be distinguished reliably from one another. The groups comprised children with autistic spectrum disorders (ASD; n = 13, all males; mean age 10 years 10 months, range 10 years 2 months to 12 years 6 months); children with primary pragmatic language impairment (PLI) but who did not have definite ASD diagnoses (n = 25, 22 males, three females; mean age 11 years 3 months, range 10 years 2 months to 12 years 5 months); and children with specific language impairment (SLI) without marked pragmatic language difficulties (n = 29, 25 males, 4 females; mean age 10 years 10 months, range 10 years 2 months to 11 years 9 months). Clinical markers examined were: the Children's Non-Word Repetition (CNRep), the Past Tense Task (PTT), and the Clinical Evaluation of Language Fundamentals, Recalling Sentences. First, it was found that the a priori groupings were not sufficiently defined and that four groups were actually present. The PLI group was in fact two separate samples: those with PLI pure and those with some autistic-like behaviours (referred to here as PLI plus, following Bishop 1998). Second, group comparisons indicated that CNRep was significantly lower for children with SLI than all other groups (although this measure was not such a good discriminator using a specificity analysis). Third, the markers were able to discriminate between all types of communication impairment in normal control participants (n = 100; 51 females, 49 males; mean age 11 years, range 10 years 5 months to 11 years 6 months) with sensitivity levels of at least 75% and specificity of 80%. Recalling Sentences was the most efficient marker for all groups. Finally, analysis showed that children with PLI plus could be accurately distinguished from all others, scoring most favourably overall on communication markers and on performance IQ scores.

Autism, primary pragmatic difficulties, and specific language impairment: can we distinguish them using psycholinguistic markers?

Three groups of children with communication disorders were examined using a series of psycholinguistic markers to explore whether the tasks could identify children with impairments other than specific language impairment (SLI), and to examine whether the different groups within this clinical population could be distinguished reliably from one another. The groups comprised children with autistic spectrum disorders (ASD; n=13, all males; mean age 10 years 10 months, range 10 years 2 months to 12 years 6 months); children with primary pragmatic language impairment (PLI) but who did not have definite ASD diagnoses (n=25, 22 males, three females; mean age 11 years 3 months, range 10 years 2 months to 12 years 5 months); and children with specific language impairment (SLI) without marked pragmatic language difficulties (n=29, 25 males, 4 females; mean age 10 years 10 months, range 10 years 2 months to 11 years 9 months). Clinical markers examined were: the Children's Non‐Word Repetition (CNRep), the Past Tense Task (PTT), and the Clinical Evaluation of Language Fundamentals, Recalling Sentences. First, it was found that the a priori groupings were not sufficiently defined and that four groups were actually present. The PLI group was in fact two separate samples: those with PLI pure and those with some autistic‐like behaviours (referred to here as PLI plus, following Bishop 1998). Second, group comparisons indicated that CNRep was significantly lower for children with SLI than all other groups (although this measure was not such a good discriminator using a specificity analysis). Third, the markers were able to discriminate between all types of communication impairment in normal control participants (n=100; 51 females, 49 males; mean age 11 years, range 10 years 5 months to 11 years 6 months) with sensitivity levels of at least 75% and specificity of 80%. Recalling Sentences was the most efficient marker for all groups. Finally, analysis showed that children with PLI plus could be accurately distinguished from all others, scoring most favourably overall on communication markers and on performance IQ scores.

The Relationship Between IQ and Reading Disabilities in English-Speaking Canadian and Spanish Children

This study was designed to examine the role of intelligence (IQ) in the definition of reading disabilities (RD) in languages with different orthographic systems. A sample of 94 Spanish children and 157 English-speaking Canadian children with RD was classified into four groups on the basis of IQ scores from the Wechsler Intelligence Scale for Children-Revised (< 80; 81-90; 91-109; 110-140). We examined the reading and spelling skills of Canadian and Spanish children as a function of Full Scale, Verbal, and Performance IQ scores. Significant differences between the languages were found when reading performance was analyzed as a function of Verbal IQ scores, in that there were some differences between the groups of Canadian children with RD but not between the groups of Spanish children. The Canadian children with Verbal IQ scores < 80 demonstrated relatively lower performance in reading and spelling skills than the Canadian groups with higher IQ scores. There were differences in reading tasks as a function of Performance IQ in English but not in Spanish. The differences in the role of IQ as a function of orthographic systems may relate to the greater significance of visual-orthographic as opposed to phonological processing in English.

Cognitive Functioning as Measured by the WISC-R

Patterns of performance on the Wechsler Intelligence Scale for Children-Revised (WISC-R) have been proposed as useful tools for the identification of children with learning disabilities (LD). However, most of the studies of WISC-R patterns in children with LD have been plagued by the lack of a typically achieving comparison group, by failure to measure individual patterns, and by the lack of a precise definition of LD. In an attempt to address these flaws and to assess the presence of patterns of performance on the WISC-R, we examined data from 121 children with typical achievement (TA), 143 children with reading disabilities (RD), and 100 children with a specific arithmetic disability (AD), ages 6 to 16 years. The results indicated that the RD and AD groups had significantly lower scores than the TA group on all the Verbal IQ subtests. Many of the children with AD and RD showed a significant difference between Verbal and Performance IQ scores, but so did many of the typically achieving children. Although there were some children with LD who showed the predicted patterns, typically, 65% or more of the children with LD did not. Furthermore, a proportion of the TA group-generally not significantly smaller than that of the RD and AD groups-showed discrepancy patterns as well. Our results indicate that the patterns of performance on intelligence tests are not reliable enough for the diagnosis of LD in individual children. Therefore, it might be more profitable to base the detection of an individual's LD on patterns of achievement test scores.