Biomedical subjects

Iser G DeLeon

Publications and source records attributed to Iser G DeLeon.

6 recordsLinked to original sources

PubMed2005

Comparison of verbal preference assessments in the presence and absence of the actual stimuli.

Stimulus preference assessments for individuals with developmental disabilities typically involve offering choices among stimuli and providing immediate access to the chosen stimuli. Several researchers have explored the utility of presenting choices verbally, thereby obviating the need to present the choices in tangible form and deliver access to those choices immediately. However, studies that have compared verbal selection to selection among tangible stimuli have nonetheless delivered the chosen stimulus following selections, in essence, manipulating the antecedent but not the consequence. It therefore remains unclear whether preference assessments that do and do not include the actual stimuli yield comparable results. The current study compared preference assessment results for three participants in which either (a) the stimuli were presented, selections were made verbally, and selection resulted in no differential consequence, or (b) the stimuli were presented both verbally and in tangible form, and selection produced access to the stimulus. Reinforcer assessments were then conducted to test contradictory predictions of reinforcer efficacy made by the two methods. Comparisons between the two assessments yielded only modest rank-order correlations (M=0.24; range, -0.17 to 0.57) that varied widely across participants. Results of the reinforcer assessments suggested that the verbal-plus-tangible stimulus preference assessment more accurately predicted reinforcer strength.

Acoustic Stimulation↗

PubMed2004

Individualized sampling parameters for behavioral observations: enhancing the predictive validity of competing stimulus assessments.

Recent studies have used pretreatment analyses, termed competing stimulus assessments, to identify items that most effectively displace the aberrant behavior of individuals with developmental disabilities. In most studies, there appeared to have been no systematic basis for selecting the sampling period (ranging from 30 s to 10 min) in which items were assessed. Unfortunately, estimates based on brief samples of behavior do not always predict the extent to which items will displace aberrant behavior over longer periods. This study first examined a method for determining an accurate individualized sample length for competing stimulus assessments, based on statistical measures of correspondence with extended effects, using a small number of items. The effects of a larger number of items were then assessed using the determined sample length. Finally, the method was validated by comparing its predictions, in terms of the reduction of problem behavior over more extended periods, to predictions based on sample durations typically used in previous investigations. For two participants, predictions based on individualized determination of sample lengths were more accurate than predictions based on typical sample lengths. These results are discussed in terms of the exchange between expediency and accuracy during competing stimulus assessments.

Autistic Disorder↗

PubMed2004

Enhancing the effects of extinction on attention-maintained behavior through noncontingent delivery of attention or stimuli identified via a competing stimulus assessment.

UNLABELLED: Recent research has shown that the noncontingent delivery of competing stimuli can effectively reduce rates of destructive behavior maintained by social-positive reinforcement, even when the contingency for destructive behavior remains intact. It may be useful, therefore, to have a systematic means for predicting which reinforcers do and do not compete successfully with the reinforcer that is maintaining destructive behavior. In the present study, we conducted a brief competing stimulus assessment in which noncontingent access to a variety of tangible stimuli (one toy per trial) was superimposed on a fixed-ratio 1 schedule of attention for destructive behavior for individuals whose behavior was found to be reinforced by attention during a functional analysis. Tangible stimuli that resulted in the lowest rates of destructive behavior and highest percentages of engagement during the competing stimulus assessment were subsequently used in a noncontingent tangible items plus extinction treatment package and were compared to noncontingent attention plus extinction and extinction alone. Results indicated that both treatments resulted in greater reductions in the target behavior than did extinction alone and suggested that the competing stimulus assessment may be helpful in predicting stimuli that can enhance the effects of extinction when noncontingent attention is unavailable. DESCRIPTORS: Attention-maintained problem behavior, competing stimuli, extinction, functional analysis, noncontingent reinforcement

Attention Deficit Disorder with Hyperactivity↗

PubMed2003

Covariation between bizarre and nonbizarre speech as a function of the content of verbal attention.

A functional analysis suggested that the bizarre speech of an individual with developmental disabilities was maintained by attention. The content of verbal attention was manipulated in two subsequent analyses and revealed that (a) bizarre speech was more frequent when attention was related to the participant's bizarre speech and (b) the participant's statements tended to reflect the content of the therapist's attention, whether bizarre or nonbizarre.

Adult↗

PubMedDate not supplied

Re-evaluation of constant versus varied punishers using empirically derived consequences.

Charlop, Burgio, Iwata, and Ivancic [J. Appl. Behav. Anal. 21 (1988) 89] demonstrated that varied punishment procedures produced greater or more consistent reductions of problem behavior than a constant punishment procedure. More recently, Fisher and colleagues [Res. Dev. Disabil. 15 (1994) 133; J. Appl. Behav. Anal. 27 (1994) 447] developed a systematic methodology for predicting the efficacy of various punishment procedures. Their procedure identified reinforcers and punishers (termed "empirically derived consequences" or EDC) that, when used in combination, reduced the destructive behavior of individuals with developmental disabilities who displayed automatically maintained destructive behavior. The current investigation combines these two lines of research by comparing the effects of constant versus varied punishers on the self-injury of two individuals with developmental disabilities. The punishing stimuli were selected via the procedures described by Fisher et al. and were predicted to be at varying levels of effectiveness. The varied presentation of punishers resulted in enhanced suppressive effects over the constant presentation of a punisher for one of two individuals, but only in comparison to a single stimulus predicted to be minimally effective. Even then, the differences were small. These results suggest that the additive effects of varied punishment are negligible if clinicians use stimuli predicted to be effective and are discussed in terms of the conditions under which stimulus variation could potentially enhance the effects of punishers.

Adolescent↗

PubMedDate not supplied

Assessment of aberrant behavior maintained by wheelchair movement in a child with developmental disabilities.

A child that used a wheelchair was anecdotally observed to display little aggressive behavior when being pushed in his wheelchair, but higher rates of aggressive behavior when movement was terminated. A functional analysis was conducted to systematically assess the relationship between aggression and wheelchair movement. The functional analysis results revealed elevated rates of aggression when it resulted in being briefly pushed in the wheelchair. This functional hypothesis was subsequently validated by teaching the child to request movement through appropriate means and demonstrating that aggression decreased under treatment conditions. These results extend prior research on functional analysis by demonstrating a previously unreported behavioral function particular to individuals with motor deficits.

Adolescent↗