William Mahoney

Reliability and Accuracy of Differentiating Pervasive Developmental Disorder Subtypes

OBJECTIVE To evaluate the ability of the DSM-IV criteria for the pervasive developmental disorders (PDD) to reliably and accurately differentiate PDD subtypes. METHOD The sample consisted of 143 children with various types of developmental disabilities. A diagnosis of PDD and PDD subtype was made by one clinician using information obtained from the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule. The raw data from the Autism Diagnostic Interview-Revised, clinical notes (excluding diagnostic opinion), Autism Diagnostic Observation Schedule, IQ, and other available data were independently assessed by three experienced raters, each of whom then made a separate, blind diagnosis. If there was any disagreement, a consensus best-estimate (CBE) diagnosis was made after discussion. To assess reliability, the agreement between the three raters was calculated using k. Accuracy was assessed by calculating the agreement between the clinicians diagnosis and the CBE and by calculating the error rates associated with the three raters using latent class analysis. RESULTS The current DSM-IV criteria show good to excellent reliability for the diagnosis of PDD, Aspergers disorder (AsD), and autism, but they show poor reliability for the diagnosis of atypical autism. The clinician (compared to the CBE) had little difficulty differentiating PDD from non-PDD children and autism from AsD but had more difficulty identifying children with atypical autism. The latent class analysis also showed that the average error rates of the three raters for a differentiation of atypical autism from autism were unacceptably high. CONCLUSIONS Although the psychometric properties of the current DSM-IV criteria for autism and AsD appear quite acceptable, there is likely to be a high rate of misclassification of children given a diagnosis of atypical autism.

Specifying PDD-NOS: A Comparison of PDD-NOS, Asperger Syndrome, and Autism

OBJECTIVE To describe the clinical characteristics of children given a diagnosis of pervasive developmental disorder-not otherwise specified (PDD-NOS) by expert clinicians and to compare these to the clinical characteristics of children given a diagnosis of autism and Asperger syndrome (AS). METHOD Two hundred sixteen children with autism, 33 with AS, and 21 with PDD-NOS were compared on measures of level of functioning (communication, daily living and social skills, IQ, and age of acquisition of language) and on various symptoms of autism (impaired communication and reciprocal social interaction and a preference for repetitive and stereotyped activities). RESULTS In terms of level of functioning measures, the PDD-NOS children had scores that were between those of the children with autism and those of the children with AS. In contrast, the PDD-NOS group had fewer autistic symptoms, especially repetitive stereotyped behaviors, than both the autism and AS groups (chi2 = 11.06, p =.004). Children with PDD-NOS could be placed into one of three subgroups: a high-functioning group (24%) who resembled AS but had transient language delay or mild cognitive impairment; a subgroup resembling autism (24%) but who had late age of onset or too severe cognitive delays or were too young to potentially meet the full diagnostic criteria for autism; and a group (52%) not fulfilling the criteria for autism because of fewer stereotyped and repetitive behaviors. CONCLUSIONS With some revision to current diagnostic criteria, a more homogenous atypical group with significant impairments in social-communication but fewer repetitive behaviors can be differentiated from the more nonspecific PDD-NOS group. This differentiation may lead to better reliability in diagnosis and to further progress in studies of etiology.

The Familial Aggregation of the Lesser Variant in Biological and Nonbiological Relatives of PDD Probands: a Family History Study

OBJECTIVE To determine the risk of the lesser variant (or PDD-like traits) in the biological and nonbiological second- and third-degree relatives of PDD probands using a screening questionnaire and to investigate the extent to which the risk of the lesser variant differs according to various characteristics of the proband. METHOD The sample consists of a series of 34 nuclear families with 2 affected PDD children (multiplex, MPX), 44 families with a single PDD child (simplex, SPX), and 14 families who adopted a PDD child. Data on characteristics of the lesser variant in 1362 biological and 337 nonbiological second- and third-degree relatives were collected from parents by telephone interview and from several maternal and paternal relatives by questionnaire. RESULTS All components of the lesser variant were more common in biological relatives (BR) than nonbiological relatives (NBR), confirming the familial aggregation of the traits. Proband characteristics associated with an increased risk of the lesser variant in relatives were a higher level of functioning and coming from a MPX family. CONCLUSIONS These findings on the familial aggregation of the lesser variant suggest that the genes for PDD also confer susceptibility to the lesser variant and that PDD may be a genetically heterogeneous disorder.

Familial Factors Influence Level of Functioning in Pervasive Developmental Disorder

OBJECTIVE To determine whether siblings with pervasive developmental disorders (PDD) tend to have the same type and number of PDD symptoms or a similar level of functioning. METHOD The familial correlations for PDD subtype, symptom totals, adaptive behaviors, and nonverbal IQ were calculated for 94 children with PDD from 46 families. RESULTS On variables measuring PDD symptoms, only impairments in nonverbal communication and verbal/nonverbal status tended to run true within families. There was no familial aggregation of PDD subtype. In contrast, measures of nonverbal IQ and adaptive behaviors in socialization and communication showed a moderate degree of familial resemblance. The degree of familial resemblance did not change if the analysis was restricted only to those families in which both affected children met criteria for autism. CONCLUSION Insofar as the familial resemblance seen in PDD is due to genetic factors, these data provide some evidence that higher- and lower-functioning PDD children may arise from separate genetic mechanisms. Current gene-mapping studies of PDD may need to take this evidence of genetic heterogeneity into account.

Lack of cognitive impairment in first-degree relatives of children with pervasive developmental disorders

OBJECTIVE The objective of this study was to test the hypothesis that mild cognitive impairments aggregate in the unaffected first-degree relatives of probands with autism or pervasive developmental disorders (PDD). METHOD The unaffected siblings and parents of 52 PDD probands and 33 Down syndrome and low birth weight controls were administered a battery of psychometric tests. The tests included measures previously found to be depressed in siblings of autistic children as well as cognitive deficits seen in PDD subjects of normal IQ. In addition, the Vineland Adaptive Behavior Scales were administered to siblings to measure the social-communication impairments found in PDD. RESULTS Neither the siblings nor parents of the PDD probands demonstrated lower cognitive or adaptive behavior scores compared with controls. Developmental histories did not reveal greater rates of social, cognitive, or language delays, nor was there evidence to suggest that relatives of subgroups of PDD probands were different from each other. CONCLUSION These findings indicate that, apart from relatives with PDD, cognitive and social impairments do not aggregate in the families of PDD probands.

My child doesn't have a brain injury, he only has a concussion.

OBJECTIVE: The term “concussion” is frequently used in clinical records to describe a traumatic head injury; however, there are no standard definitions of this term, particularly in how it is used with children. The goals of this study were to examine the clinical correlates of the concussion diagnosis and to identify the factors that lead to the use of this term in a regional pediatric center. METHODS: Medical data were prospectively collected from 434 children with traumatic brain injury who were admitted to a Canadian childrens hospital. A proportional hazards regression was used to examine the association of the concussion diagnosis and the times until discharge and school return. A classification-tree analysis modeled the clinical correlates of patients who received a concussion diagnosis. RESULTS: The concussion label was significantly more likely to be applied to children with mild Glasgow Coma Scale scores of 13 to 15 (P = .03). The concussion label was strongly predictive of earlier hospital discharge (odds ratio [OR]: 1.5; 95% confidence interval [CI]: 1.2–1.9; P = .003) and earlier return to school (OR: 2.4 [95% CI: 1.6–3.7]; P < .001). A diagnosis of a concussion was significantly more likely when the computed-tomography results were normal and the child had lost consciousness. CONCLUSIONS: Children with mild traumatic brain injuries have an increased frequency of receiving the concussion label, although the label may also be applied to children with more-severe injuries. The concussion diagnosis is associated with important clinical outcomes. Its typical use in hospital settings likely refers to an impact-related mild brain injury, in the absence of indicators other than a loss of consciousness. Clinicians may use the concussion label because it is less alarming to parents than the term mild brain injury, with the intent of implying that the injury is transient with no significant long-term health consequences.

Brief Report: Relationship Between Non-verbal IQ and Gender in Autism

It has been proposed that females at risk for autism are protected in some way, so that only those with the greatest genetic liability are affected. Consequently, affected male siblings of females with autism should be more impaired than affected male siblings of male probands. One hundred and ninety-four (194) families with a single child with autism (simplex, SPX) and 154 families with more than one child with autism (multiplex, MPX) were examined on measures of severity, including non-verbal IQ. Among SPX families, girls had lower IQ than boys, but no such differences were seen among MPX families. Similarly, the affected brothers of girls with autism were no different from affected brothers of male probands. These data suggest that MPX and SPX families differ with respect to the relationship between gender and IQ.

High phenotypic correlations among siblings with autism and pervasive developmental disorders

The objective of this study was to examine familial factors influencing clinical variation in sibships that contained at least 2 children affected with autism or another form of pervasive developmental disorder (PDD). The sample included a total of 60 families, 23 with multiple cases of PDD and 37 with a single affected child. Measurements of IQ, adaptive behaviors in socialization and communication, and autistic symptoms were taken on all affected children. A high intraclass correlation, especially on IQ and an index of social behaviors, was observed between affected children from the same family. In contrast, low correlations were observed on measurements of IQ and adaptive behavior between affected and unaffected children from the same family. These data indicate that variation in severity of PDD is influenced by familial, and probably genetic, mechanisms. The results are discussed in relation to current theories on the genetics of autism and the heritable mechanisms underlying variations in clinical severity.

A Balanced Protocol for Return to School for Children and Youth Following Concussive Injury

Background. Few protocols exist for returning children/youth to school after concussion. Childhood concussion can significantly affect school performance, which is vital to social development, academic learning, and preparation for future roles. The goal of this knowledge translation research was to develop evidence based materials to inform physicians about pediatric concussion. Methods. The Return to School (RTS) concussion protocol was developed following the National Institute for Health and Care Excellence procedures. Results. Based on a scoping review, and stakeholder opinions, an RTS protocol was developed for children/youth. This unique protocol focuses on school adaptation in 4 main areas: (a) timetable/attendance, (b) curriculum, (c) environmental modifications, and (d) activity modifications. Conclusion. A balance of cognitive rest and timely return to school need to be considered for returning any student to school after a concussion. Implementation of these new recommendations may be an important tool in prevention of prolonged absence from school and academic failure while supporting brain recovery.

High Functioning Autism and Childhood Disintegrative Disorder in Half Brothers

Childhood Disintegrative Disorder (CDD) is grouped with autism as a subtype of Pervasive Developmental Disorder (PDD) in ICD-10 and DSM-IV. This is the first report of autism and CDD cosegregating within a sibship. J. P. and M. P. are half-brothers with the same mother. J. P. is an 18-year-old with impairments in communication, social reciprocity, and stereotypies and was diagnosed with autism. M. P. is a 7-year-old who developed normally to 2 years 4 months. He then underwent a profound regression, becoming nonverbal and socially withdrawn, and lost adaptive skills. Investigations did not reveal any neurodegenerative process. M. P. was diagnosed with CDD. The rarity of the two conditions suggests a shared transmissible mechanism. The implications for autism/PDD genetic studies are discussed.