Value of computerised tomography in children with non-specific mental subnormally

Familial and syndromic forms of arachnoid cyst implicate genetic factors in disease pathogenesis

Arachnoid cysts (ACs) are the most common space-occupying lesions in the human brain and present significant challenges for clinical management. While most cases of ACs are sporadic, nearly 40 familial forms have been reported. Moreover, ACs are seen with increased frequency in multiple Mendelian syndromes, including Chudley-McCullough syndrome, acrocallosal syndrome, and autosomal recessive primary ciliary dyskinesia. These findings suggest that genetic factors contribute to AC pathogenesis. However, traditional linkage and segregation approaches have been limited in their ability to identify causative genes for ACs because the disease is genetically heterogeneous and often presents asymptomatically and sporadically. Here, we comprehensively review theories of AC pathogenesis, the genetic evidence for AC formation, and discuss a different approach to AC genomics that could help elucidate this perplexing lesion and shed light on the associated neurodevelopmental phenotypes seen in a significant subset of these patients.

Neurodevelopmental outcomes in children with large temporal arachnoid cysts

OBJECTIVE Management of children with large temporal arachnoid cysts (TACs) remains controversial, with limited data available on their neurodevelopmental outcome. The aim of this study was to examine neurodevelopmental outcomes in children with large TACs. METHODS In this medical center-based cohort study, 25 patients (19 males) who were diagnosed in childhood with large TACs (9 patients [36%] with a Galassi type II and 16 patients [64%] with a Galassi type III TAC) were examined. The mean ± SD age at assessment was 11.1 ± 5.6 years (range 2.7-22 years). Twelve patients (48%) had right-sided, 12 (48%) had left-sided, and 1 (4%) had bilateral cysts. Nine patients (36%) underwent surgery for the cyst. The siblings of 21 patients (84%) served as control participants. Neurodevelopmental function was assessed using the Adaptive Behavior Assessment System (ABAS), Vanderbilt Behavioral Rating Scale (VBRS), and Developmental Coordination Disorder Questionnaire (DCDQ), and quality of life was measured using the treatment-oriented screening questionnaire (TOSQ). The results of all instruments except for TOSQ were compared with those of the sibling control participants. RESULTS The mean ± SD ABAS score of the patients was 93.3 ± 20.09 compared with 98.3 ± 18.04 of the sibling control participants (p = 0.251). Regarding the incidence of poor outcome (ABAS score < 80), there was a trend for more patients with TAC to have poor outcome than the sibling controls (p = 0.058). Patients who underwent surgery scored significantly worse with regard to the VBRS total score compared with those who did not (p = 0.020), but not on ABAS, DCD, or TOSQ. The mean score of the cognitive and psychological items on TOSQ was lower than that for the physical items (p < 0.001). CONCLUSIONS Children with a large TAC performed similarly to their sibling control participants in neurodevelopmental function. However, a subgroup of those with cysts did have an increased risk for poor outcomes in general function. Neurodevelopmental assessment should be part of the management of all patients with TAC.

Comprehensive evaluation of the child with intellectual disability or global developmental delays

Global developmental delay and intellectual disability are relatively common pediatric conditions. This report describes the recommended clinical genetics diagnostic approach. The report is based on a review of published reports, most consisting of medium to large case series of diagnostic tests used, and the proportion of those that led to a diagnosis in such patients. Chromosome microarray is designated as a first-line test and replaces the standard karyotype and fluorescent in situ hybridization subtelomere tests for the child with intellectual disability of unknown etiology. Fragile X testing remains an important first-line test. The importance of considering testing for inborn errors of metabolism in this population is supported by a recent systematic review of the literature and several case series recently published. The role of brain MRI remains important in certain patients. There is also a discussion of the emerging literature on the use of whole-exome sequencing as a diagnostic test in this population. Finally, the importance of intentional comanagement among families, the medical home, and the clinical genetics specialty clinic is discussed.

Genetic evaluation of intellectual disabilities

All children with an intellectual disability (mental retardation) or global developmental delay should have a comprehensive evaluation to establish the etiology of the disability. A specific etiologic diagnosis offers the opportunity to discuss treatment, prognosis, and genetic recurrence risk. A diagnosis also avoids unnecessary testing and can lead to opportunities for improved health and functional outcomes. The key elements of the diagnostic evaluation are the medical and developmental history, 3-generation family history, dysmorphologic examination, neurologic examination, and judicious use of the laboratory and neuroimaging. All published guidelines for the evaluation of children with intellectual disability acknowledge that there is a substantial percentage of patients who are undiagnosed after a comprehensive evaluation and who deserve ongoing follow-up for the purpose of establishing a diagnosis. Recently, studies of the clinical application of array comparative genomic hybridization (aCGH) to individuals with intellectual disability indicate that this approach provides a diagnosis in as much as 10% of patients and that this technique is replacing the use of fluorescent in situ hybridization for subtelomere imbalances now used for such patients when the standard karyotype is normal. The literature suggests that history and examination by an expert clinician will lead to a diagnosis in 2 of 3 patients in whom a diagnosis is made. Laboratory studies alone, including neuroimaging, provide a diagnosis in the remaining one third. The approach to the evaluation of the patient in whom an etiologic diagnosis is not suspected after the history and physical examinations includes a standard karyotype, Fragile X molecular genetic testing, aCGH, and neuroimaging, based on the evidence to date. One can expect rapid changes in the microarray technology in the near future.

Clinical genetic evaluation of the child with mental retardation or developmental delays

This clinical report describes the clinical genetic evaluation of the child with developmental delays or mental retardation. The purpose of this report is to describe the optimal clinical genetics diagnostic evaluation to assist pediatricians in providing a medical home for children with developmental delays or mental retardation and their families. The literature supports the benefit of expert clinical judgment by a consulting clinical geneticist in the diagnostic evaluation. However, it is recognized that local factors may preclude this particular option. No single approach to the diagnostic process is supported by the literature. This report addresses the diagnostic importance of clinical history, 3-generation family history, dysmorphologic examination, neurologic examination, chromosome analysis (> or =650 bands), fragile X molecular genetic testing, fluorescence in situ hybridization studies for subtelomere chromosome rearrangements, molecular genetic testing for typical and atypical presentations of known syndromes, computed tomography and/or magnetic resonance brain imaging, and targeted studies for metabolic disorders.

Diagnostic investigations in individuals with mental retardation: a systematic literature review of their usefulness

There are no guidelines available for diagnostic studies in patients with mental retardation (MR) established in an evidence-based manner. Here we report such study, based on information from original studies on the results with respect to detected significant anomalies (yield) of six major diagnostic investigations, and evaluate whether the yield differs depending on setting, MR severity, and gender. Results for cytogenetic studies showed the mean yield of chromosome aberrations in classical cytogenetics to be 9.5% (variation: 5.4% in school populations to 13.3% in institute populations; 4.1% in borderline-mild MR to 13.3% in moderate-profound MR; more frequent structural anomalies in females). The median yield of subtelomeric studies was 4.4% (also showing female predominance). For fragile X screening, yields were 5.4% (cytogenetic studies) and 2.0% (molecular studies) (higher yield in moderate-profound MR; checklist use useful). In metabolic investigations, the mean yield of all studies was 1.0% (results depending on neonatal screening programmes; in individual populations higher yield for specific metabolic disorders). Studies on neurological examination all showed a high yield (mean 42.9%; irrespective of setting, degree of MR, and gender). The yield of neuroimaging studies for abnormalities was 30.0% (higher yield if performed on an indicated basis) and the yield for finding a diagnosis based on neuroradiological studies only was 1.3% (no data available on value of negative findings). A very high yield was found for dysmorphologic examination (variation 39-81%). The data from this review allow conclusions for most types of diagnostic investigations in MR patients. Recommendations for further studies are provided.

Diagnostic evaluation of developmental delay/mental retardation: An overview

Mental retardation (MR) is one of the few clinically important disorders for which the etiopathogenesis is still poorly understood. It is a condition of great concern for public health and society. MR is currently defined as a significant impairment of cognitive and adaptive functions, with onset before age 18 years. It may become evident during infancy or early childhood as developmental delay (DD), but it is best diagnosed during the school years. MR is estimated to occur in 1-10% of the population, and research on its etiology has always been a challenge in medicine. The etiopathogenesis encompasses so many different entities that the attending physician can sometimes feel a "virtual panic," starting a wide-range diagnostic evaluation. The Consensus Conference of the American College of Medical Genetics has recently established guidelines regarding the evaluation of patients with MR [Curry et al., 1997], emphasizing the high diagnostic utility of cytogenetic studies and neuroimaging in certain clinical settings. However, since then there has been substantial progress in molecular cytogenetics and neuroimaging techniques, the use of which has allowed recognition and definition of new disorders, thus increasing the diagnostic yield. This review will focus on the most appropriate investigations shown to be, at present, necessary to define the etiology of DD/MR, in the context of recommendations for the clinical evaluation of the patient with undiagnosed MR.

Etiologic determination of childhood developmental delay

To determine the etiologic yield in young children with developmental delay referred to sub-specialty clinics for evaluation. Over an 18-month period, all children less than 5 years of age referred to the ambulatory pediatric neurology or developmental pediatrics clinics of the Montreal Children's Hospital for initial evaluation of a suspected developmental delay were enrolled. Features evident on history or physical examination were determined at intake as were the laboratory tests (and their rationale) requested by the evaluating physicians. Six months post initial assessment, detailed chart review was undertaken to determine if an etiology was found and the basis for such a determination. Bivariate and multivariate logistic regression was used to test for associations between factors present at intake and successful ascertainment of an underlying etiology. Two hundred and twenty-four children met study criteria. Etiologic yield varied across childhood developmental delay subtypes, and was 44/80 for global developmental delay [GDD] (55%), 13/22 for motor delay [MD] (59.1%), 3/72 for developmental language disorders [DLD] (4.2%), and 1/50 for autistic spectrum disorders [ASD] (2%). For GDD, the presence of historical features or findings on physical examination was associated with greater likelihood for successful etiologic determination with the following items significant in multiple logistic regression analysis; microcephaly, antenatal toxin exposure, focal findings. For MD, physical findings or the co-existence of a cerebral palsy symptom complex predicted a successful search for etiology. For both groups, the severity of the delay did not predict etiologic yield. For both groups, a small number of etiologic categories accounted for the majority of diagnoses made. Etiologic yield in childhood developmental delay is largely dependent on the specific developmental delay subtype. Paradigms for systematic evaluation of this common child health problem can be suggested, however they await validation.

Etiologic yield of single domain developmental delay: a prospective study

OBJECTIVE

To determine the etiologic yield in young children with single domain developmental delay (either developmental language disorder or isolated motor delay) after a specialty diagnostic evaluation.

METHODS

During an 18-month period, all children <5 years of age, who were consecutively referred to pediatric neurology or developmental pediatric clinics at a single tertiary pediatric center, were prospectively enrolled. Etiologic yield was determined after completion of clinical assessments and selected laboratory studies requested by the evaluating physician.

RESULTS

Seventy-two children (60 boys) were found to have a developmental language disorder, and 22 children (11 boys) had isolated motor delay, of whom 6 had an associated diagnosis of cerebral palsy. An etiologic diagnosis was rarely made in the children with developmental language disorder (3/72, 4.1%). Laboratory investigations (metabolic, cytogenetic, imaging), aside from audiometry, were uniformly uninformative. In those children with isolated motor delay, an etiology was apparent in more than half (13/22, 59%). Slightly more than half (7/13, 54%) of etiologies identified in this group were potentially preventable. Successful etiologic determination in children with motor delay often had an impact on recurrence risk estimation, medical management, or specific therapy offered (8/13, 62%). The presence of physical findings on initial assessment was found to be highly predictive of successful etiologic determination in children with isolated motor delay (13/17 vs 0/5, P =.002).

CONCLUSION

Etiologic yield differs substantially according to the subgroup of single domain developmental delay.

Etiologic yield of subspecialists' evaluation of young children with global developmental delay

OBJECTIVE

To determine the etiologic yield of subspecialists' evaluation of young children with global developmental delay. In addition, variables that may predict finding an underlying etiology were also identified.

METHODS

All children <5 years of age, referred over an 18-month period to subspecialty services for initial evaluation of a suspected developmental delay, were prospectively enrolled. Diagnostic yield was ascertained after the completion of clinical assessments and laboratory investigations requested by the evaluating physician.

RESULTS

Ninety-nine children (71 boys) were found to have global developmental delay; 96% had a mild or moderate delay documented. An etiologic diagnosis was determined in 44. Four diagnoses (cerebral dysgenesis, hypoxic-ischemic encephalopathy, toxin exposure, chromosomal abnormalities) accounted for 34 of 44 (77%) of the diagnoses made. The presence of co-existing autistic traits was associated with significantly decreased diagnostic yield (0/19 vs 44/80, P <.0001), whereas specific historical features (eg, family history, toxin exposure, and perinatal difficulty; 23/32 vs 21/67, P =.0002) and findings on physical examination (eg, dysmorphology, microcephaly, and focal motor findings; 35/48 vs 9/51, P <.0001) were significantly associated with identifying a diagnosis. Multiple logistic regression analysis identified antenatal toxin exposure, microcephaly, focal motor findings, and the absence of autistic traits as significant predictor variables for the identification of an etiology.

CONCLUSION

An etiologic diagnosis is often possible in the young child with global developmental delay, particularly in the absence of autistic features. Etiologic yield is augmented by presence of specific findings on history or physical examination on initial assessment.

The evaluation of the child with a global developmental delay

The child with a global developmental delay presents a diagnostic challenge to the practitioner. The spectrum of possible etiologic diagnosis and laboratory investigations that could be pursued are quite extensive. This article presents the rationale for diagnostic testing in this population and provides guidelines to those tests that should be pursued.

Radiological findings in developmental delay

This article reviews the neuroimaging findings in patients with nonsyndromic mental retardation and global developmental delays. The frequency and type of abnormal neuroimaging findings in this patient population are discussed. Specifically addressed are the issues of which patients should have neuroimaging studies in light of (in the vernacular) "cost-benefit" analysis. The extension of these studies to "milder" developmental delays, and other neurodevelopmental disorders are also discussed.

Evaluation of mental retardation: recommendations of a Consensus Conference: American College of Medical Genetics

A Consensus Conference utilizing available literature and expert opinion sponsored by the American College of Medical Genetics in October 1995 evaluated the rational approach to the individual with mental retardation. Although no uniform protocol replaces individual clinician judgement, the consensus recommendations were as follows: 1. The individual with mental retardation, the family, and medical care providers benefit from a focused clinical and laboratory evaluation aimed at establishing causation and in providing counseling, prognosis, recurrence risks, and guidelines for management. 2. Essential elements of the evaluation include a three-generation pedigree: pre-, peri-, and post-natal history, complete physical examination focused on the presence of minor anomalies, neurologic examination, and assessment of the behavioral phenotype. 3. Selective laboratory testing should, in most patients, include a banded karyotype. Fragile X testing should be strongly considered in both males and females with unexplained mental retardation, especially in the presence of a positive family history, a consistent physical and behavioral phenotype and absence of major structural abnormalities. Metabolic testing should be initialed in the presence of suggestive clinical and physical findings. Neuroimaging should be considered in patients without a known diagnosis especially in the presence of neurologic symptoms, cranial contour abnormalities, microcephaly, or macrocephaly. In most situations MRI is the testing modality of choice. 4. Sequential evaluation of the patient, occasionally over several years, is often necessary for diagnosis, allowing for delineation of the physical and behavioral phenotype, a logical approach to ancillary testing and appropriate prognostic and reproductive counseling.

Study of subarachnoid spaces in children with idiopathic mental retardation

The aim of this study was to assess quantitatively the size of the subarachnoid space in children with "idiopathic" mental retardation. The extent of various cerebrospinal fluid compartments was measured in 106 brain computed tomographic examinations of children with idiopathic mental retardation, and the results were compared with the corresponding normative data. The third ventricle was enlarged in 77% of the cases. A mild degree of diffuse widening of the subarachnoid spaces was found in about 30% of the patients. These morphologic alterations are additional observations supporting the hypothesis that "idiopathic" mental retardation has a biologic basis.

Diagnostic yield of the neurologic assessment of the developmentally delayed child

OBJECTIVE

The aim of this study was to determine the etiologic yield of the neurologic assessment of a consecutive cohort of developmentally delayed children.

STUDY DESIGN

A retrospective chart review was carried out on all patients referred to a single university-based pediatric neurologist for evaluation of global developmental delay from July 1991 to December 1993. Patients referred because of isolated speech or motor delay or autism or those who had been previously evaluated by another neurologist were excluded.

RESULTS

A total of 77 patients were identified; 47 were male, and 62 were referred by a pediatrician. Neurologic evaluation did not confirm global delay in 10, and 8 did not complete diagnostic evaluation; one child was included in both groups. Of the remaining 60, an etiologic diagnosis was suspected by the referring physician at the time of referral in 13. Although parents suspected a delay at a mean age of 0.66 (+/- 0.69) year, children were examined by the neurologist at a mean age of 3.58 (+/- 2.42) years. Twenty-five were mildly delayed, 23 were moderately delayed, and 12 were severely delayed. Diagnostic studies (history, physical examination, and selected investigations, including screens for metabolic disease, karyotype, fragile X testing, electroencephalography, and neuroimaging) yielded an etiologic diagnosis in 38 (63.3%) of the 60 patients. Etiologic categories included cerebral dysgenesis (16.7%), hypoxic-ischemic encephalopathy (10.0%), chromosomal abnormalities (10%), toxins (8.3%), metabolic disorders (5.0%), and neurocutaneous (3.3%), neuromuscular (3.3%), genetic/dysmorphic (3.3%), and epileptic (3.3%) syndromes. Etiologic yield was equivalent across categories and degree of developmental delay.

CONCLUSION

Referral to a pediatric neurologist and application of a selected battery of investigations yield etiologic findings with important implications with respect to management, prognosis, and recurrence risk estimate in a significant portion of globally delayed children.

Value of brain CT scan in children with febrile convulsions

Studies specifically dealing with the value of brain CT scans in different types of febrile convulsion are lacking when compared to the large amount of studies on other favorable convulsive disorders. This study is correlation study between children who presented with febrile convulsions (n = 38) and the results of their brain CT scans. Twenty four patients had risk factors for subsequent epilepsy (group A), 3 of them had abnormal CT scans in the form of mild diffuse brain atrophy, and all 3 patients were found to have prior neurodevelopmental deficits. The other 14 patients did not have such risk factors (group B) and had normal brain CT scans. Despite the small size of the study, the results are unequivocal, and it can be concluded that brain CT scan is not indicated in the management of simple or complex febrile convulsions. Brain CT may be justifiable, but may not be clinically useful in the management of febrile convulsion patients with prior neurodevelopmental deficits.

Pediatric assessment of the child with developmental delay

With the recent mandate for early intervention services, the pediatrician is more involved than ever in the identification and evaluation of children with developmental disabilities. Developmental surveillance at routine visits and listening to parental concerns are crucial in the early diagnosis of developmental delay so that therapeutic interventions can be provided at a time when there is a good chance of decreasing disability and family stress. Medical evaluations and consultations must be prudent and based on a thorough history and physical. The pediatrician must have the knowledge and skills to coordinate medical care and to counsel and provide support to the child and family as they receive habilitative services and come to terms with the developmental diagnoses.

Isolated neurodevelopmental delay in childhood: clinicoradiological correlation in 170 patients

CT findings on 170 patients presenting with isolated moderate to severe neurodevelopmental delay have been compared with the final diagnosis. MRI was undertaken in 29 patients. Eighty per cent of the patients remained undiagnosed, and although the MRI findings were abnormal in 65.5% compared with only 30% of the CT examinations, imaging uncommonly suggested a specific diagnosis. Biochemical and chromosomal investigations were significantly more diagnostic. The results of these studies should restrict the number of non-contributory neuroradiological examinations. The superior intrinsic contrast of MRI will detect more lesions, particularly in white matter, but these are rarely diagnostic and where access to MRI is limited, CT is usually adequate.

Evaluation of the child with idiopathic mental retardation

A review of the advances in diagnostic techniques for evaluation of children with idiopathic mental retardation is presented. The current status of the use of clinical genetics, cytogenetics, molecular genetics, and neuroimaging in evaluating children with mental retardation is emphasized. Special attention is given to the evaluation of children with mental retardation and "autism" or "cerebral palsy."

Myelination patterns on magnetic resonance of children with developmental delay

Magnetic resonance (MR) imaging was performed in 30 children with unexplained developmental delay who had associated neurological abnormalities such as seizures, spasticity, hypotonia, ataxia or poor vision. No child had a history of regression, preterm birth or neonatal cerebral injury. CT scans were performed before MR in all cases and were either normal or showed only mild atrophy. At least two MR sequences were obtained for all patients. Nine children had delayed or absent myelination on MR, one had patchy white-matter abnormalities, and in one patient myelination was topographically normal, but of inappropriately low signal intensity. MR was abnormal in six of seven children who had abnormal brainstem auditory evoked potentials (BAEP), and was normal in nine of 11 patients who had a normal BAEP. MR may have a useful rôle in demonstrating abnormal white-matter maturation in children with unexplained neurodevelopmental delay, particularly when abnormalities are found on BAEP studies.

Magnetic resonance imaging of inflammatory and demyelinating white-matter diseases of childhood

Magnetic resonance imaging (MRI) was performed on 36 children and two adults (with clinical presentation during childhood) with white-matter disease of the central nervous system. Abnormalities were readily demonstrated in patients with multiple sclerosis, acute disseminated encephalomyelitis, leucodystrophies and subacute sclerosing panencephalitis: MRI demonstrated the extent and distribution of abnormalities more clearly than computed tomography for all these disorders. The abnormalities tended to be asymmetrical and multifocal in multiple sclerosis and acute disseminated encephalomyelitis, and more confluent and symmetrical in the leucodystrophies. Children with clinically isolated optic neuritis had a significantly lower frequency of MRI brain-lesions than adults with the same disorder. MRI should be regarded as the radiological investigation of choice when white-matter disease is suspected in children.

Developmental Foix-Chavany-Marie syndrome in identical twins

Foix, Chavany, and Marie described a syndrome of faciopharyngoglossomasticatory diplegia resulting from bilateral anterior opercular infarction. We describe identical twins who have a developmental form of the syndrome. The twins, aged 41 years, were the product of a normal pregnancy and birth, but had subsequent delayed motor milestones, seizures, poor language development, mild mental retardation, drooling, absent gag reflexes, inability to protrude the tongue, brisk jaw jerks, impaired fine finger movements, symmetrical brisk reflexes, flexor plantar responses, and mildly spastic gait. Magnetic resonance imaging showed bilateral perisylvian cortical dysplasia compatible with polymicrogyria and incomplete opercular formation.

Slight impairment of psychomotor skills in children after treatment of acute lymphoblastic leukemia

Several studies have reported a decline in intelligence and cognitive functions in survivors of childhood acute lymphoblastic leukemia (ALL). Other investigators, however, have found no intellectual impairment in these children. Fifty-one long-term survivors of ALL, having been treated according to the protocols of the BFM Study Group from 1970 to 1979, were assessed retrospectively using neurophysical methods. The results were compared with those obtained from 30 patients with other malignancies, who had received neither radiation therapy to the central nervous system (CRT) nor any methotrexate during chemotherapy. Additionally, neurological examinations and cranial computed tomography (CCT) were performed. neuropsychological examinations included verbal functions, intelligence (performance), psychomotor speed, motor skills and sensory integration. The results of verbal tests and the IQs, tested by nonspeed-related measures, were within normal limits in both groups. About one-third of all patients showed mild disturbances of psychomotor speed and motor skills. Children with leukemia had lower scores than those with solid tumors for nearly all tasks, but only tests for sensory integration revealed significant differences between former ALL patients and tumor patients. Furthermore, the following results were obtained related to different therapeutic modalities: The higher total radiation doses had been during CRT (maximum 24 GY), the more neuropsychological functions were impaired, particularly motor accuracy and sensory integration. These disturbances improved with the length of survival. Widening of subarachnoidal space was found in 33% of the CCT obtained. There was no correlation between the intellectual functions of the survivors and the CCT abnormalities. Neurological findings mainly consisted of slight fine motor disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Computed tomography in non-specific mental retardation and idiopathic epilepsy

In 29 children with mental retardation and infantile spasms, cranial computed tomography findings were abnormal in 75% and this finding may lead to modification of treatment or influence genetic counseling. In 41 children with mental retardation and other forms of epilepsy abnormal computed tomography findings were much less frequent and were not relevant to treatment.