Lower Performance IQ Research Articles

Electroencephalographic abnormalities during sleep in children with developmental speech‐language disorders: a case–control study

Earlier research has suggested a link between epileptiform activity in the electroencephalogram (EEG) and developmental speech-language disorder (DSLD). This study investigated the strength of this association by comparing the frequency of EEG abnormalities in 45 language-normal children (29 males, 16 females; mean age 6y 11mo, SD 1y 10mo, range 4y-9y 10mo) and 54 community-ascertained children (35 males, 19 females; mean age 5y 7mo, SD 1y 6mo, range 4y-9y 11mo) with a diagnosis of severe DSLD, defined as a score at least 2 SD below the mean on at least one speech-language measure, and a performance IQ of at least 80 points. All participants underwent sleep EEGs after sedation. Children with DSLD also had detailed speech-language, hearing, and psychological assessments. Results failed to support the previously identified strong association between abnormal EEG and DSLD. There was a weak, non-significant relationship between DSLD and epileptiform EEG. Epileptiform EEG was significantly associated with low performance IQ (p=0.04). This study draws into question previously reported associations between epileptiform activity and DSLD probably because it examined a purer cohort of children with more severe language difficulties who did not have seizures.

Children With Congenital Hypothyroidism: Long-Term Intellectual Outcome After Early High-Dose Treatment

We aim to determine long-term intellectual outcome of adolescents with early high-dose treated congenital hypothyroidism (CH). Sixty-three prospectively followed children with CH were assessed at age of 14 y with the Wechsler Intelligence Scale for Children-Revised and compared with 175 healthy controls. Median age at onset of treatment was 9 d (range 5-18 d) and median starting dose of levothyroxine (L-T4) was 14.7 microg/kg/d (range 9.9-23.6 microg/kg/d). Full-scale intelligence quotient (IQ) was significantly lower than in controls after adjustment for socioeconomic status (SES) and gender (101.7 versus 111.4; p < 0.0001). Children with athyreosis had a lower performance IQ than those with dysgenesis (adjusted difference 7.6 IQ scores, p < 0.05). Lower initial thyroxine (T4) levels correlated with poorer IQ (r = 0.27, p = 0.04). Lower SES was associated with poorer IQ, in particular in children with CH (interaction, p = 0.03). Treatment during childhood was not related to IQ at age 14 y. Adolescents with CH manifest IQ deficits when compared with their peers despite early high-dose treatment and optimal substitution therapy throughout childhood. Those adolescents with athyreosis and lower SES are at particular risk for adverse outcome. Therefore, early detection of intellectual deficits is mandatory in children with CH.

Effects of MRI abnormalities on WAIS-R performance in solvent abusers.

To clarify how chronic solvent abuse affects cognitive function using magnetic resonance imaging as an index of brain damage. A total of 25 chronic solvent abusers underwent magnetic resonance imaging with quantitative neurometry and Wechsler Adult Intelligence Scales revised. The abusers with white matter change (n=10) showed significantly (P<0.05) lower performance IQ, especially in Digit Symbol subtest (P<0.01). Also, the severity of pontine atrophy was significantly correlated with PIQ (r=0.60, P<0.01). These data indicate that solvent abuse causes the decline in the test performance reflecting cognitive and fine motor dysfunction and that white matter changes and pontine atrophy may have some roles in this decline.

Neuropsychological functioning following craniopharyngioma removal

The neuropsychological functioning of patients who had undergone surgical removal of craniopharyngiomas was compared to that of an endocrine control group composed of patients with nontumor hypopituitarism, an obese control group, and a normal control group. Neuropsychological assessments consisting of measures of intelligence, memory, attention, and executive functioning were carried out. The craniopharyngioma group had lower Performance IQ than did the normal control group, but their Performance IQ was comparable to that of the hypopituitarism and obese control groups. The craniopharyngioma patients did not differ in Verbal or Full Scale IQs from the remaining groups. There were no group differences on measures of verbal or nonverbal memory, ability to sustain attention, or executive functioning including measures of verbal or figural fluency, nonverbal problem solving, ability to copy a complex geometric figure, and visual motor and visual sequencing skills. The group mean scores on the measures of intelligence and neuropsychological abilities for the craniopharyngioma patients were in the low-average to average range. While craniopharyngioma patients can have significant morbidity including endocrine and visual deficits as well as obesity resulting from hyperphagia, neuropsychological deficits are not always present. Their neuropsychological outcome is more benign than some previous studies have suggested.

Patterns of cerebral white matter damage and cognitive impairment in adolescents born very preterm

There is increasing evidence about the presence of white matter damage in subjects with a history of premature birth, even in those classified as good outcome because of an apparently normal development. Although intellectual performance is within normal limits in premature children it is significantly decreased compared to paired controls. The purpose of this study was to investigate the relationship between a lower performance intelligence quotient and white matter damage in preterm adolescents. The sample comprised 44 adolescents (mean age±S.D.: 14.4±1.6 years) born before 32 weeks of gestational age and 43 term-born adolescents (14.5±2.1 years). Individual voxel-based morphometry analyses demonstrated that 35/44 (80%) preterm subjects had white matter abnormalities. The centrum semiovale and the posterior periventricular regions were the most frequently affected areas. Correlation analysis showed that in preterms the performance intelligence quotient correlated with the whole-brain white matter volume (r=0.32; P=0.036) but not with grey matter volume. Complementary analysis showed that low scores in the Digit Symbol subtest, a measure of processing speed, in the preterm group correlated with reductions in white matter concentration. These results suggest that white matter damage is highly common and that it persists until adolescence. Hence, diffuse white matter loss may be responsible for performance intelligence quotient and processing speed decrements in subjects with very preterm birth.

Neuropsychological (NP) Dysfunction and Neuroimaging Abnormalities in Neurologically Intact Adult Patients with Sickle Cell Disease (SCD).

Background. Brain dysfunction may be the most important and least studied problem afflicting the aging SCD population. 25% of neurologically intact pediatric SCD patients have NP dysfunction and silent CNS infarction. In children, age is associated with progressive decline in NP scores suggesting adults are at risk for progressive brain injury and NP decline.Objective. To determine the extent of NP impairment, the prevalence of MRI abnormalities, and their relationship in neurologically asymptomatic adult SCD patients compared to national norms and matched controls.Methods. Patients (21–55 yrs) with HbSS, normal neurologic exams and no history of stroke or abnormal neuroimaging, were recruited from 11 centers and screened for mental status and depression. The patient to control ratio goal was 3:1. After consenting, participants completed NP tests that assessed verbal and nonverbal intelligence, academic achievement, executive functioning, processing speed (PS), attention, and memory. Tests included the Wechsler Adult Intelligence Scale (WAIS-III), the Wechsler Memory Scales (WMS-III), the Woodcock-Johnson Tests of Achievement (WJ III), the Test of Everyday Attention (TEA), and others. Participants underwent standardized brain MRI read for atrophy and lesions. Volumetric analysis (vMRI) quantitated white and grey matter.Results. This is a report of 138 of the 150 planned SCD subjects and 37 controls: 62% female, 21–29 yrs, with mean hemoglobin (Hb) 8.2g/dl. 32% and 39% of patients scored one standard deviation (below 86) on the WAIS-III Performance IQ (PIQ) and PS index (PSI) scores compared to 16% in national norms. 26% and 22% of patients scored below 86 on the WMS-III visual immediate and immediate memory scales compared to 16% in national norms. Controlling for age, gender, and education, patients and controls differed significantly on the WAIS-III PSI Score, −14.1 (95% CI of −19.2 to −9.0) and the WJ-III including reading, math and following directions. Subtests of attention and flexibility of thought of the TEA significantly decreased with age in patients but not controls. In 82 patients with MRIs, 63% had an abnormal MRI or NP dysfunction, 38% had atrophy and/or ischemic lesions, and 18% had ischemic lesions only. Low PIQ and PSI were significantly associated with ischemic lesions. In vMRI, adjusting for age and gender, hippocampal volume in patients was 541.1 μL < controls (95% CI of 212.0, 870.3) and CSF volume in patients was 16 mL > controls (95% CI of 1.7, 31.5). These dfferences were significant. Patient Hb was a significant independent predictor of verbal IQ, PIQ, PSI, math, and executive function (Pearson r = .20 –.28).Conclusion. NP dysfunction and/or undetected brain injury affect the majority of neurologically intact adults with SCD, especially in areas of executive functioning, reading and math fluency. Patients with lower Hb have lower IQ scores. Ischemic lesions, alone, do not account for the extent of the NP impairment observed. Hb, age, and hippocampal volume were predictive of NP dysfunction, suggesting a link between reduced oxygenation, neuronal loss, and cognitive impairment. This supports the importance of a transfusion trial to improve NP function.

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.

Psychiatric and Neurological Characteristics of Murder Defendants Referred for Pretrial Evaluation

After literature review, this paper presents the largest study to date (n = 270) of psychiatric and neurological characteristics of accused murderers in the United States. This retrospective record review of pretrial detainees undergoing competency to stand trial and criminal responsibility evaluations examined demographic characteristics, psychiatric diagnosis, substance use patterns, Intelligence Quotient (IQ), and results of electroencephalogram (EEG), neuroimaging (MRI or CT) and neurological examination. Substance use and mood/adjustment disorders were common. Neuroimaging was abnormal in 18% of subjects and was associated with lower Performance IQ. EEG and neurological exam findings were not associated with measured cognitive impairment. While 16% of subjects had a FS IQ < 70, only 6% were diagnosed with mental retardation. Subjects with a psychotic disorder (p = 0.001) or an anxiety disorder (p = 0.005) were more likely to use a knife than other subjects in the study. Violence risk assessment in these patients must not only involve inquiry about firearm availability.

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.

Large variability in performance IQ associated with postnatal morbidity, and reduced verbal IQ among school-aged children born preterm.

To assess cognitive ability in a population-based group of prematurely born school-aged children and to relate these findings to postnatal morbidity. The study group consisted of a cohort of 51 children born preterm, 43 (26 boys, 17 girls) of whom were available for psychological evaluation At evaluation, their median age was 10 y (range 8-11 y). They were all born between 1988 and 1991, with gestational age less than 29 wk (median 27, range 24-28). Their median birthweight was 1060g (range 450-1450). The Wechsler Intelligence Scale for Children (WISC-III) was used, and the test results were compared with those of a standardized, age-matched, normative group of children. Thirteen children (30%) performed below average [intelligence quotient (IQ) < 80] for Full Scale IQ (FSIQ). Thirty-six children had a Verbal IQ (VIQ) below the mean value of 100 [84%, 95% confidence interval 73-95%], p < 0.0001. The Performance IQ (PIQ) was within the expected range of a normal population, although a large variability was observed. Discrepancies between VIQ and PIQ of more than 15 IQ units were found in 42% of the children. High postnatal morbidity (days with assisted ventilation, number of blood transfusions) and low birthweight standard deviation scores (SDS) were associated with lower PIQ than VIQ, while low postnatal morbidity and high birthweight were associated with higher PIQ than VIQ. This cohort of preterm children had reduced overall verbal capacity independent of morbidity, and a large variability in performance capacity that was associated with postnatal morbidity. The findings suggest that there are different mechanisms influencing the outcome of verbal and performance capacity in preterm children.

Comorbidity in children with severe developmental language disability

In a cohort of 2359 children, screened for severe developmental language disability (DLD) at 3 y of age, 45 children were identified as true positives. The development, concerning DLD and comorbidity of 41 of these children still living in the municipality of Uppsala was followed up to school start. Criteria for comorbidity were: (a) suspected or diagnosed neuropsychiatric/neuro‐developmental disability according to information from the Child Habilitation Centre and the Child Psychiatric Centre or (b) low performance IQ, signs of activity/distractibility problems according to a psychologist's examination. By school start, 61% of the children with severe DLD were identified with comorbidity. Conclusion: Severe DLD is often combined with other disabilities within the neuropsychiatric/neurodevelopmental spectra. The comorbidity might not be obvious at 3 y of age—the age at which severe DLD is effectively identified by the 3‐y screening programme. This in turn stresses the necessity of multidisciplinary teamwork both at the referral level and during the therapy work.

Comorbidity in children with severe developmental language disability.

In a cohort of 2359 children, screened for severe developmental language disability (DLD) at 3 y of age, 45 children were identified as true positives. The development, concerning DLD and comorbidity of 41 of these children still living in the municipality of Uppsala was followed up to school start. Criteria for comorbidity were: (a) suspected or diagnosed neuropsychiatric/neurodevelopmental disability according to information from the Child Habilitation Centre and the Child Psychiatric Centre or (b) low performance IQ, signs of activity/distractibility problems according to a psychologist's examination. By school start, 61% of the children with severe DLD were identified with comorbidity. Severe DLD is often combined with other disabilities within the neuropsychiatric/neurodevelopmental spectra. The comorbidity might not be obvious at 3 y of age--the age at which severe DLD is effectively identified by the 3-y screening programme. This in turn stresses the necessity of multidisciplinary teamwork both at the referral level and during the therapy work.

Cognitive development in VCFS

The 22q11.2 microdeletion (velocardiofacial syndrome, VCFS) results in a complex pattern of psychoeducational and neurocognitive deficits. Mean full-scale IQ scores are in the range of borderline intellectual function, but academic achievement scores are generally in the low–normal range. A dichotomy is often found between higher Verbal IQ scores and lower Performance IQ, paralleled by relative strength in Reading and Spelling, but weakness in Math. Language skills are also typically delayed and remain impaired later in life, and psychiatric disorders can be found in both children and adults with the syndrome. On-going neurocognitive research suggests that the impairment in mathematical ability may be associated with poor visual–spatial skills. This would be consistent with theoretical models that link arithmetic skills with visual attention and spatially referenced representations of magnitude. Neuroimaging investigations indicate that these skills may all depend critically on the inferior parietal lobes, and lead to our hypothesis that these may be dysfunctional in the 22q11.2 syndrome. Early reports find no association between cognitive ability in the syndrome and the presence of cardiac malformations.

Intelligence quotient and neuropsychological profiles in patients with schizophrenia and in normal volunteers

Background: The objective of this study was to examine neuropsychological performance at different intelligence quotient (IQ) levels in schizophrenia. Methods: Thirty-six patients with schizophrenia were matched with 36 normal control subjects in two IQ groups: low average (81–94) and average (95–119). Performance level (IQ group main effects) and profile shape (IQ group × function interactions) were compared. Results: Current IQ was lower than estimated premorbid intellectual ability in both patient groups. Patients also displayed poorer neuropsychological function than same-IQ control subjects, suggesting neuropsychological dysfunction beyond their already compromised IQ. Patients had different profile shapes than control subjects, but profile shapes were consistent within patients and control subjects at each IQ level. Patients at both levels had higher verbal and lower performance IQ than control subjects. Abstraction-executive function was one of the lowest neuropsychological scores in both patient groups. Average IQ patients had nonsignificantly better overall neuropsychological performance than low average control subjects, but the effect size (.43) was quite small relative to the IQ difference (effect size = 2.57). Conclusions: Neuropsychological patterns in schizophrenia tend to be consistent at different IQ levels. Even schizophrenia patients with normal current IQs manifest substantial neuropsychological compromise relative to their level of general intellectual ability. The results strengthen the argument that neurocognitive deficits are core deficits of schizophrenic illness.

Cognitive abilities in children with congenital muscular dystrophy: correlation with brain MRI and merosin status.

The aim of the study was to evaluate whether children with merosin-positive or merosin-deficient congenital muscular dystrophy (CMD) show any cognitive impairment and whether this is related to brain abnormalities on magnetic resonance imaging (MRI). Twenty-two patients (age range: 5.8-15.3 years) were assessed by the Wechsler Intelligence Scales. Twelve were merosin-positive and ten merosin-deficient. One child had severe mental retardation and could not be tested. The full scale IQ in the remaining 21 ranged from 51 to 134, the verbal IQ ranged from 78 to 136 and the performance from 51 to 136. Of the twelve children with normal merosin one had a mild delay (IQ < 75) and two were borderline (IQ 75-95). Of the ten children with merosin-deficiency, one showed severe mental retardation and could not be tested, one showed a mild delay and two had borderline results. While the children with merosin deficiency with the typical diffuse white matter changes on MRI had normal scores, the children who in addition had cerebellar hypoplasia had lower performance IQ. The child with cortical dysplasia had severe mental retardation. Our results suggest that the spectrum of cognitive abilities in CMD is very wide even within genetically homogeneous conditions.

Obsessive-compulsive disorder and ventromedial frontal lesions: clinical and neuropsychological findings.

The authors sought to determine the long-term outcome of subjects with severe and refractory obsessive-compulsive disorder (OCD) who had undergone ventromedial frontal leukotomy during the 1970s. Special emphasis was given to the analysis of specific lesion sites. Sixteen OCD subjects who had undergone ventromedial frontal leukotomy were evaluated clinically and neuropsychologically and compared to seven well comparison OCD subjects without leukotomy. The 16 leukotomized subjects were divided into three groups according to the main lesion sites as determined by current magnetic resonance imaging scans. The leukotomized OCD subjects showed significant improvement of obsessive-compulsive symptoms; subjects with frontostriatal lesions tended to have improved most. The subjects with combined diagnoses of OCD and obsessive personality disorder (N = 3) had improved significantly less. Of 11 subjects with lesions of the ventral striatum, eight had developed substance dependence postoperatively. Intellectual functions were largely preserved in subjects with ventromedial frontal lesions only or frontostriatal lesions. However, all subjects showed subnormal performance on the Wisconsin Card Sorting Test. Subjects with lesions of the dorsolateral frontal convexity also showed memory problems, attentional slowing, and lower performance IQ. Restricted ventromedial frontal leukotomy should be discussed as a last-resort treatment for severe and refractory OCD but not obsessive personality disorder. Lesions of the ventral striatum were significantly related to the occurrence of substance dependence, suggesting a role of this area in human addictive behavior.

What underlies inflectional error patterns in genetic dysphasia?

We compare linguistic and non-linguistic explanations which attempt to account for the difficulties that individuals with genetic dysphasia experience with inflectional morphology. The non-linguistic explanations that we focus on are low performance IQ and performance deficits which are manifested at the level of auditory processing or at the mapping between representation and articulatory output. We argue that none of these hypotheses can account for the patterns observed; the impairment lies in the construction of the grammar itself. We hypothesise that the dysphasic grammar lacks sublexical (morphological) features which mark inflectional information in languages. Consequently, the grammar does not contain the morphological rules which introduce these features and, following from this, there is no structure internal to ‘inflected’ words. We summarise the experimental evidence which supports this hypothesis.

INTELLIGENCE AND ACADEMIC ACHIEVEMENT AT EIGHT YEARS OF AGE IN CHILDREN RECOVERED FROM NEONATAL CHRONIC LUNG DISEASE (CLD) † 1228

Neonatal CLD is known to be associated with developmental delay during infancy. Robertson et al, studying children born in the 1970's, found that at 8 years of age, children recovered from CLD had lower IQ and poorer school performance as compared with controls [Pediatrics 1992;89:365-72]. In the current study we investigated whether these effects of CLD would be found in children born more recently. We also explored the effect of CLD on adaptive development. We evaluated 50 children, 8 years of age, who had: 1) birth weight < 1500 grams, 2) no major anomaly, 3) requirement for assisted ventilation in the neonatal period, 4) a normal neonatal cranial ultrasound or an examination showing only an uncomplicated subependymal hemorrhage, and 5) no signs of cerebral palsy at one year of age. 24 children a a history of requiring supplemental oxygen at 36 weeks post-conceptional age (CLD groups); the other 26 children did not (controls). The 2 groups were similar in terms of birth weight, gestational age, gender, and race. More mothers of CLD children had less than 12 years of education [CLD - 24% vs controls - 8%]. The evaluation included the Wechsler Intelligence Scale for Children - Third Edition, the Wechsler Individual Achievement Test (WIAT), and the Vineland Adaptive Behavior Scale. Unadjusted comparisons were made using the Wilcoxon rank sum test. Comparisons adjusted for years of maternal education were made using linear regression. CLD children had lower Performance IQ [presented as median (range in parentheses)] [CLD: 86 (52-108); controls: 96 (64-130); p=0.004], lower Full-Scale IQ [CLD: 87 (52-110); controls: 101 (65-128); p=0.02], and lower Vineland Adaptive Behavior Scales composite score [CLD:94(51-122); controls: 109 (81-120); p=0.03]. These differences persisted when adjusted for years of maternal education. CLD children also had lower scores on the WIAT for reading, spelling, and math, but these differences did not persist when controlling for years of maternal education. In summary, CLD is associated with lower intelligence and delayed adaptive development at eight years of age; these problems, however, need not result in lower school achievement.

Comparison of adult manifestations of schizophrenia with onset before and after 15 years of age.

We examined 19 adult cases of early-onset schizophrenia (onset before age 15) and 19 controls (schizophrenia with onset between age 15 and 35). Being matched by sex, length of hospitalization and living environment while the present age between groups showed no difference, patients were compared on psychopathological symptom measures and intelligence quotient (IQ). Results showed that early-onset cases scored significantly higher on Scales for the Assessment of Negative Symptoms and had lower performance IQ. No group difference in positive symptoms measure from Brief Psychiatric Rating Scale and full IQ was noted. It suggested that when early-onset patients grew up, phenomenologically, they resembled the schizophrenia of usual early-adult onset in the positive symptom dimension, but with more negative symptoms, which may be fundamental in this group of patients.

Cognitive impairment in Duchenne muscular dystrophy

Cognitive function and dystrophin gene mutations were investigated in 50 DMD patients (mean age 11.1 yr; range 3.5–20.3). General intelligence assessment showed 31% of patients with Wechsler full intelligence quotient (FIQ) lower than 75 (normal values: 100 ± 14), and only 24% with appropriate FIQ level. Modal distribution of Wechsler verbal, performance, and FIQs, and Raven IQs was normal. Verbal IQ was more affected than performance IQ (PIQ) only in the younger group of subjects. Low PIQ correlated with the presence of macroglossia, detected in 13 out of 50 patients. Impairment of productive language was of non-dysphasic nature and correlated with defects of short-term memory, which was also affected in non-verbal skills. DMD patients shared the same spectrum of neuropsychological defects, regardless of whether they were or were not mentally retarded. The proportion of patients with dystrophin gene deletions was 64%. No statistically significant correlations were found between genetic data and psychometric assessment. Finally, ( 18F)-fluorodeoxyglucose positron emission tomography studies demonstrated cerebellar hypometabolism in all the DMD patients examined and variable involvement of associative cortical areas. These findings suggest a possible role of the cerebral and cerebellar hypometabolism in the cognitive impairment of DMD.