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Biomedical subjects

L Tuff

Publications and source records attributed to L Tuff.

9 recordsLinked to original sources
PubMed2000

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.

Adolescent↗
PubMed1999

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.

Activities of Daily Living↗
PubMed1996

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.

Autistic Disorder↗
PubMed1995

Parents and collateral relatives of children with pervasive developmental disorders: a family history study.

The objective of this study was to see whether, using the family history method, the risk for pervasive developmental disorder (PDD), cognitive impairments, and other psychiatric symptoms is greater in the parents and collateral relatives of probands with PDD compared to a control group. A semistructured family history interview was carried out with the parents of 52 probands with PDD and 33 parents of controls. Rates of cognitive impairments and psychiatric problems were not found more frequently in parents or relatives of PDD probands compared to relatives of controls, but four cases of PDD were reported among the extended families of the PDD probands. The relatives with PDD were related to the probands through the maternal line, possibly suggesting some form of maternal influence on inheritance or reduced penetrance in females with the PDD genotype.

Adolescent↗
PubMed1993

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.

Adolescent↗
PubMed1990

Asperger's syndrome and autism: neurocognitive aspects.

The objectives of this study were to see: (1) whether children with Asperger's Syndrome (AS) have similar neurocognitive deficits compared to nonretarded, or high-functioning autistic (HFA) children; and (2) whether the essential cognitive deficit among these children is in language or abstract problem solving. Subjects with AS, HFA, and a control group of socially impaired child psychiatric outpatient controls (OPC) were compared on a battery of neuropsychological tests. The results indicated that the AS and HFA groups differed little but that large differences from the OPC were observed on all tests. When the AS and HFA with FSIQ above 85 were compared to the OPC, outstanding deficits on motor coordination, language comprehension, and facial recognition were observed. Finally, some evidence is presented to suggest that the pattern of deficits of AS and HFA subjects varied by developmental level. The implications of these results for a neurological theory of autism are discussed.

Adolescent↗
PubMed1990

The clinical significance of neurocognitive impairments among children with psychiatric disorders: diagnosis and situational specificity.

The overall objective of this paper is to assess the clinical significance of neurocognitive impairments (NCI) among children with psychiatric disorders. One hundred and fifty-three children referred to a mental health clinic underwent neuropsychological testing. Their parents were interviewed to obtain background information and data on their children's behavior. Parents and teachers also filled out behavior checklists. The results suggest that neurocognitive impairments are: (1) more strongly associated with externalizing rather than internalizing psychiatric diagnoses; and (2) are correlated with psychiatric symptoms at school, but not at home. The implications for understanding the impact of neurocognitive impairments on the situational specificity of psychiatric symptoms are discussed.

Affective Symptoms↗
PubMed1975

Kindling, unit discharge patterns and neural plasticity.

Two approaches to the study of the kindling phenomenon were discussed: 1) an attempt to identify the pattern of neural activity required to produce the changes underlying kindling and 2) an investigation into the nature of those changes. Three experiments were reported that used the neocortical transcallosal system as a monosynaptic model system in which to study possible synaptic mechanisms of the kindling effect. Experiment I showed an increase in the transcallosal evoked potential following neocortical kindling. Experiment II showed an increase in the strength of the transcallosal evoked cell discharge following neocortical kindling. Experiment III reported the results of an histological examination of neocortical tissue in kindled and non-kindled animals using the Golgi-Cox technique. Spine density, spine dimension and branching were measured for pyramidal cell apical dendrites. No differences were found between primary and secondary (contralateral) foci or between kindled and non-kindled animals.

Animals↗