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Query: UMLS:C0004352 (autism)
 32,579 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent research demonstrated that when autistic children are presented a discrimination task with multiple cues, they typically respond to an abnormally limited number, usually one, of the available cues. This phenomenon, termed "stimulus overselectivity," has been implicated as a possible basis for many of the behavioral deficits characteristic of autism. The present investigation was conducted to systemically analyze the effects of changing the schedules of reinforcement during discrimination training on subsequent stimulus overselectivity. Twelve autistic children were taught a discrimination involving multiple visual cues, with a CRF schedule of reinforcement. The children were then overtrained on either the same (CRF) schedule or on a partial (VR:3) reinforcement schedule. Subsequent overselectivity on single-cue test trials was then assessed. Results suggested that significantly less overselectivity occurred when the children were presented with the VR:3 reinforcement schedule during overtraining. These results are discussed in terms of variables influencing overselectivity and in terms of implications for designing treatment procedures for autistic children.
J Autism Dev Disord 1979 Dec
PMID:The effects of schedule of reinforcement on stimulus overselectivity in autistic children. 52 31

The purpose of this study was to assess autistic children's ability to maximize reinforcement, sample among available stimuli, and respond to extinction. Responding to five concurrent reinforcement schedules (CRF, FR 2, FR 4, FR 7, and FR 11) was monitored and compared to groups of mental age-matched and chronological age-matched normal children. When a given child consistently selected a given schedule of reinforcement, it was then put on extinction, and both perseveration and responding to the remaining (intact) schedules of reinforcement were monitored. The results showed, first, that while normal children selected the richest schedule of reinforcement, autistics did not maximize reinforcement, typically selecting one of the thinner schedules available. Second, the autistic children sampled less, and less efficiently, than the normal children. Third, the autistic children proved to be much less responsive to extinction, perseverating longer than the normal children before switching to a new reinforcement schedule. Fourth, whenever extinction proved to be a problem in the autistics, it was quickly achieved by a simple change in the stimulus conditions. These results are discussed as possible "keystone" deficits, which may be causally related to many of the behavioral deficits of autism and which might be important target behaviors for treatment.
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PMID:Comparing autistic and normal children along the dimensions of reinforcement maximization, stimulus sampling, and responsiveness to extinction. 404 84

When to suspect and thus investigate for inborn errors of purine and pyrimidine metabolism is a dilemma for even the most observant investigator. Often parents of affected children, or a history involving siblings, can provide valuable clues. The recognition of new purine and pyrimidine disorders requires skill and serendipity. But even identifying known disorders can prove difficult, since they cover a broad spectrum of illnesses, can have more than one symptom, or lead to early death. This problem is compounded by the fact that they are relatively recently described and therefore often little known, either in the clinic or laboratory. The considerable heterogeneity in clinical expression within families as well as between families means that asymptomatic homozygotes may not be recognized or can present at any time from early childhood through adolescence up to their eighth decade. Consequently, all siblings should be screened. These disorders should be suspected in any case of unexplained anaemia, failure to thrive, susceptibility to recurrent infection, or neurological deficits with no current diagnosis, including autism, cerebral palsy, delayed development, deafness, epilepsy, self-mutilation, muscle weakness, the inability to walk or talk, and-unusual in children and adolescents-gout, sometimes with renal disease. Some disorders present with radiolucent kidney stones, in acute or chronic renal failure, alone or with any of the above, or as an intolerance/sensitivity to therapy (e.g. 5-fluorouracil in malignancies or azathioprine immunosuppression in organ transplantation), often with life-threatening consequences. Several parameters need to be evaluated to ensure correct diagnosis. Pitfalls which can mask diagnosis using only a single test are renal failure, blood transfusion, diet or drugs.
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PMID:When to investigate for purine and pyrimidine disorders. Introduction and review of clinical and laboratory indications. 921 Nov 94

Studies on the "interpolation of reinforcement" effect (IRE) suggest that switching from an intermittent (INT) to a continuous (CRF) reinforcement schedule may result in less resistance to extinction than if extinction had followed INT alone. The finding has been examined with both human and animal participants using both free- and restricted-operant research preparations with equivocal results. In the present study, the IRE was examined in four young children diagnosed with autism using a free-operant preparation. Participants were matched into pairs and were exposed, in a counterbalanced order, to extinction following CRF "interpolated" between INT and extinction, and to extinction following INT alone. Resistance to extinction was examined by comparing the number of responses emitted during extinction and the number of sessions required to reach an extinction criterion. Responding may be less resistant to extinction following interpolated CRF reinforcement than following INT alone. Methodological refinements necessary for more conclusively demonstrating the IRE are discussed.
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PMID:The effects of interpolated reinforcement on resistance to extinction in children diagnosed with autism: a preliminary investigation. 1207 96

Congenital anomalies of the kidney and urinary tract (CAKUT) occur have an incidence of about 1% and they are one of the most common birth defects. CAKUT is the most common cause of end stage renal disease in children, leading to high morbidity and mortality in these patients. Recent studies indicate a strong genetic component in the determination of CAKUT. The genetic architecture of these malformations involves both point mutations and structural variants. The recent improvement in next-generation sequencing technologies resulted in a boost on discovery of new genes involved in CAKUT. Results from micro-array study have demonstrated that rare structural variants are an important source of genetic variation in patients with CAKUT. Moreover, these structural variants have been proven to be associated with developmental disorders that develop later in life, especially neurodevelopment diseases, such as autism, schizophrenia, epilepsy, intellectual disability, and others. The easy pre-natal diagnosis of CAKUT by ultrasound and the possibility of a rapid molecular diagnosis in a significant fraction of patients, implicate the kidney and urinary tract as new possible sentinels for other diseases that develop later in life, bearing strong implications for personalized medicine.
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PMID:[Genetic Basis of Congenital Anomalies of the Kidney and Urinary Tract]. 2647 62