Development and validation of the Arizona Cognitive Test Battery for Down syndrome

Neurocognitive assessment in individuals with intellectual disabilities requires a well-validated test battery. To meet this need, the Arizona Cognitive Test Battery (ACTB) has been developed specifically to assess the cognitive phenotype in Down syndrome (DS). The ACTB includes neuropsychological assessments chosen to 1) assess a range of skills, 2) be non-verbal so as to not confound the neuropsychological assessment with language demands, 3) have distributional properties appropriate for research studies to identify genetic modifiers of variation, 4) show sensitivity to within and between sample differences, 5) have specific correlates with brain function, and 6) be applicable to a wide age range and across contexts. The ACTB includes tests of general cognitive ability and prefrontal, hippocampal and cerebellar function. These tasks were drawn from the Cambridge Neuropsychological Testing Automated Battery (CANTAB) and other established paradigms. Alongside the cognitive testing battery we administered benchmark and parent-report assessments of cognition and behavior. Individuals with DS (n = 74, ages 7–38 years) and mental age (MA) matched controls (n = 50, ages 3–8 years) were tested across 3 sites. A subsample of these groups were used for between-group comparisons, including 55 individuals with DS and 36 mental age matched controls. The ACTB allows for low floor performance levels and participant loss. Floor effects were greater in younger children. Individuals with DS were impaired on a number ACTB tests in comparison to a MA-matched sample, with some areas of spared ability, particularly on tests requiring extensive motor coordination. Battery measures correlated with parent report of behavior and development. The ACTB provided consistent results across contexts, including home vs. lab visits, cross-site, and among individuals with a wide range of socio-economic backgrounds and differences in ethnicity. The ACTB will be useful in a range of outcome studies, including clinical trials and the identification of important genetic components of cognitive disability

Decreasing signs of negative affect and correlated self-injury in an individual with mental retardation and mood disturbances.

We evaluated the effects of an enriched environment, based on a paired-choice preference assessment, on both rates of self-injurious behavior (SIB) and percentage of session intervals during which signs of negative affect were displayed by a woman with mental retardation and a mood disorder. Results suggested that SIB and signs of negative affect were highly correlated and that the enriched environment effectively reduced both

Evaluation of a multiple-stimulus presentation format for assessing reinforcer preferences.

We compared three methods for presenting stimuli during reinforcer-preference assessments: a paired-stimulus format (PS), a multiple-stimulus format in which selections were made with replacement (MSW), and a multiple-stimulus format in which selections were made without replacement (MSWO). Results obtained for 7 participants showed moderate to high rank-order correlations between the MSWO and PS procedures and a similar number of identified reinforcers. In addition, the time to administer the MSWO procedure was comparable to that required for the MSW method and less than half that required to administer the PS procedure. Subsequent tests of reinforcement effects revealed that some stimuli selected in the PS and MSWO procedures, but not selected in the MSW procedure, functioned as reinforcers for arbitrary responses. These preliminary results suggest that the multiple-stimulus procedure without replacement may share the respective advantages of the other methods

Clarifying an ambiguous functional analysis with matched and mismatched extinction procedures.

Results of functional analysis were ambiguous in suggesting that self-injurious behavior (SIB) was maintained by escape, sensory reinforcement, or both. To help clarify these results, we compared escape extinction, sensory extinction, and the combined treatments. Sensory extinction proved to be a necessary and sufficient treatment, whereas escape extinction failed to decrease SIB. These analyses helped to clarify the function of SIB and to identify an effective and efficient treatment

Choices between positive and negative reinforcement during treatment for escape-maintained behavior.

Positive reinforcement was more effective than negative reinforcement in promoting compliance and reducing escape-maintained problem behavior for a child with autism. Escape extinction was then added while the child was given a choice between positive or negative reinforcement for compliance and the reinforcement schedule was thinned. When the reinforcement requirement reached 10 consecutive tasks, the treatment effects became inconsistent and reinforcer selection shifted from a strong preference for positive reinforcement to an unstable selection pattern