Using single-case experiments to support evidence-based decisions : how much is enough?

For practitioners, the use of single-case experimental designs (SCEDs) in the research literature raises an important question: How many single-case experiments are enough to have sufficient confidence that an intervention will be effective with an individual from a given population? Although standards have been proposed to address this question, current guidelines do not appear to be strongly grounded in theory or empirical research. The purpose of our article is to address this issue by presenting guidelines to facilitate evidence-based decisions by adopting a simple statistical approach to quantify the support for interventions that have been validated using SCEDs. Specifically, we propose the use of success rates as a supplement to support evidence-based decisions. The proposed methodology allows practitioners to aggregate the results from single-case experiments to estimate the probability that a given intervention will produce a successful outcome. We also discuss considerations and limitations associated with this approach

Assessment and treatment of vocal stereotypy associated with television: a pilot study

A 6-year-old boy diagnosed with autism participated in a pilot study showing that (a) television was associated with increased vocal stereotypy and (b) sitting was associated with lower levels of vocal stereotypy. Subsequently, we reduced vocal stereotypy while the television was on by reinforcing sitting on a variable-interval schedule. Results suggest that conditional percentages may be useful for identifying alternative behaviors as part of treatments for stereotypy

Assessment and treatment of stereotypy in an individual with Cornelia de Lange syndrome and deafblindness

Background Several researchers have reduced engagement in stereotypy in individuals with intellectual disability and deafblindness using interventions containing a punishment component. The purpose of our study was to examine whether we could produce reductions in stereotypy in an individual with Cornelia de Lange syndrome and deafblindness by using noncontingent and differential reinforcement only. Method We used single-case experimental designs to examine the effects of noncontingent reinforcement alone and in combination with differential reinforcement of sitting on mouthing, tapping, and appropriate behaviour. Results Noncontingent access to edible items reduced mouthing whereas access to tactile stimuli did not. Combining noncontingent access to tactile items with differential reinforcement reduced mouthing and tapping while strengthening appropriate behaviour. Conclusions Antecedent- and reinforcement-based interventions were effective at reducing engagement in stereotypy in an individual with Cornelia de Lange syndrome and deafblindness without relying on punishment. However, more research is necessary to replicate our findings

Preliminary effects of parent-implemented behavioural interventions for stereotypy

Objective: The purpose of our study was to replicate and extend previous research on using multicomponent behavioural interventions designed to reduce engagement in stereotypy by examining their effects when implemented by parents over several months. Methods: We used an alternating treatment design to examine the effects of the parent-implemented interventions on engagement in stereotypy and appropriate behaviour in three children with autism and other developmental disabilities. Results: The parent-implemented multicomponent treatments reduced vocal stereotypy in all three participants and increased engagement in appropriate behaviour in two participants. These effects persisted up to 24 weeks following the parent training sessions. Conclusions: Altogether, our preliminary results support (a) the involvement of parents as behaviour change agents to reduce engagement in stereotypy and (b) the scheduling of regular, but infrequent (i.e. weekly to monthly), follow-up meetings to monitor the effects of behavioural interventions in outpatient and home-based service delivery models

Preliminary effects of conditioned establishing operations on stereotypy

We repeatedly paired preferred stimuli with known establishing properties and poster boards (i.e., neutral stimuli) to examine whether these poster boards would acquire the effects of a conditioned establishing operation in five children with autism. Following pairing, the poster boards, which had been previously shown to be neutral, increased immediate or subsequent engagement in stereotypy for three of five participants. The results suggest that it is possible to condition establishing operations for stereotypy and that this process may occur inadvertently. We discuss the potential clinical implications of the results, as well as the need for future research to replicate our findings

Effects of multiple interventions for reducing vocal stereotypy: Developing a sequential intervention model

Despite the availability of several interventions designed to reduce engagement in vocal stereotypy, few studies have compared two or more interventions together. Consequently, practitioners have limited amount of data to make informed decisions on whether an intervention may be more suitable than another to begin treating vocal stereotypy. The purpose of the study was to address this limitation by examining the direct and collateral effects of multiple interventions in 12 individuals with autism and other developmental disabilities in order to guide the development of a sequential intervention model. Using single-case experimental designs, we conducted a series of four experiments which showed that (a) noncontingent music generally produced more desirable outcomes than differential reinforcement of alternative behavior, (b) differential reinforcement of other behavior reduced vocal stereotypy in two participants for whom noncontingent music had failed to do so, (c) the addition of simple prompting procedures may enhance the effects of the interventions, and (d) the effects of noncontingent music may persist during sessions with extended durations. Based on these results, we propose a sequential intervention model to facilitate the initial and subsequent selection of an intervention most likely to reduce vocal stereotypy while producing desired collateral outcomes

A Flexible Inventory of Survey Items for Environmental Concepts Generated via Special Attention to Content Validity and Item Response Theory

We demonstrate how many important measures of belief about the environmental suffer from poor content validity and inadequate conceptual breadth (dimensionality). We used scholarship in environmental science and philosophy to propose a list of 13 environmental concepts that can be held as beliefs. After precisely articulating the concepts, we developed 85 trial survey items that emphasized content validity for each concept. The concepts’ breadth and the items’ content validity were aided by scrutiny from 17 knowledgeable critics. We administered the trial items to 449 residents of the United States and used item response theory to reduce the 85 trial items to smaller sets of items for use when survey brevity is required. The reduced sets offered good predictive ability for two environmental attitudes (R2 = 0.42 and 0.46) and indices of pro-environmental behavior (PEB, R2 = 0.23) and behavioral intention (R2 = 0.25). The predictive results were highly interpretable, owing to their robust content validity. For example, PEB was predicted by the degree to which one believes nature to be sacred, but not by the degree of one’s non-anthropocentrism. Concepts with the greatest overall predictive ability were Sacredness and Hope. Belief in non-anthropocentrism had little predictive ability for all four response variables—a claim that previously could not have been made given the widespread poverty of content validity for items representing non-anthropocentrism in existing instruments. The approach described here is especially amenable to incremental improvement, as other researchers propose more informative survey items and potentially important concepts of environmental beliefs we overlooked

Off-shell effects in dilepton production from hot interacting mesons

The production of dielectrons in reactions involving a_1 mesons and pions is studied. We compare results obtained with different phenomenological Lagrangians that have been used in connection with hadronic matter and finite nuclei. We insist on the necessity for those interactions to satisfy known empirical properties of the strong interaction. Large off-shell effects in dielectron production are found and some consequences for the interpretation of heavy ion data are outlined. We also compare with results obtained using experimentally-extracted spectral functions.Comment: 14 pages, LaTeX2e, 2 figure

Relativistic quantum transport theory of hadronic matter: the coupled nucleon, delta and pion system

We derive the relativistic quantum transport equation for the pion distribution function based on an effective Lagrangian of the QHD-II model. The closed time-path Green's function technique, the semi-classical, quasi-particle and Born approximation are employed in the derivation. Both the mean field and collision term are derived from the same Lagrangian and presented analytically. The dynamical equation for the pions is consistent with that for the nucleons and deltas which we developed before. Thus, we obtain a relativistic transport model which describes the hadronic matter with $N$, $\Delta$ and $\pi$ degrees of freedom simultaneously. Within this approach, we investigate the medium effects on the pion dispersion relation as well as the pion absorption and pion production channels in cold nuclear matter. In contrast to the results of the non-relativistic model, the pion dispersion relation becomes harder at low momenta and softer at high momenta as compared to the free one, which is mainly caused by the relativistic kinetics. The theoretically predicted free $\pi N \to \Delta$ cross section is in agreement with the experimental data. Medium effects on the $\pi N \to \Delta$ cross section and momentum-dependent $\Delta$-decay width are shown to be substantial.Comment: 66 pages, Latex, 12 PostScript figures included; replaced by the revised version, to appear in Phys. Rev.