Enhancing the scientific credibility of single-case intervention research: Randomization to the rescue.

In recent years, single-case designs have increasingly been used to establish an empirical basis for evidence-based interventions and techniques in a variety of disciplines, including psychology and education. Although traditional single-case designs have typically not met the criteria for a randomized controlled trial relative to conventional multiple-participant experimental designs, there are procedures that can be adopted to create a randomized experiment in this class of experimental design. Our two major purposes in writing this article were (a) to review the various types of single-case design that have been and can be used in psychological and educational intervention research and (b) to incorporate randomized experimental schemes into these designs, thereby improving them so that investigators can draw more valid conclusions from their research. For each traditional single-case design type reviewed, we provide illustrations of how various forms of randomization can be introduced into the basic design structure. We conclude by recommending that traditional single-case intervention designs be transformed into more scientifically credible randomized single-case intervention designs whenever the research conditions under consideration permit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single-case designs and clinical biofeedback experimentation

Rigorous evaluation of the effects of biofeedback with clinical populations is necessary, but practical problems often preclude utilization of between-groups experimental designs involving large numbers of clients with clinically relevant problems. Single-case experimental designs provide a viable alternative for answering most research questions. In addition, single-case designs possess several distinct advantages for biofeedback research, including a focus on clinical significance, the use of variability as data not error, unique procedures for establishing generality of findings, and an ability to deal with ethical concerns in clinical research. Basic procedures in the use of single-case experimental designs are described and illustrations in clinical biofeedback research are provided.     

Single-case methodology in psychotherapy process and outcome research.

Delineates and explains the essential characteristics of single-case research methodology applied within the domain of psychotherapy research. Single-case research is presented as a subclass of intrasubject research in which aggregation across Ss is avoided and the generality of one's findings is addressed through replication on a case-by-case basis. The basic ways in which single-case designs vary are also discussed, and 3 basic types of single-case research are differentiated: (1) single-case experiments, (2) single-case quantitative analyses, and (3) case studies. Furthermore, some of the major weaknesses in current single-case psychotherapy research are identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Myths, misconceptions, and missed opportunity: Single-case designs and counseling psychology.

The status of single-case designs in counseling psychology is reviewed. Also, reasons for the underuse of these designs by counseling psychologists are discussed. Finally, potential contributions (1) in research linking process and outcome, (2) in group counseling, (3) across a variety of theoretical approaches, and (4) to evaluation and quality assurance in clinical practice are described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of single-case methodology in psychotherapy research.

Discusses a new psychotherapy research strategy, the experimental analysis of single cases, which is being increasingly employed in behavior modification studies. The major single-case experimental designs used in these studies include the reversal design, withdrawal design, multiple schedule design, and multiple baseline design. Examples of these designs are presented, and the advantages and disadvantages of each design are critically discussed. Possible merits and limitations of applying controlled single-case methodology to the general area of psychotherapy research are also explored. It is concluded that in spite of limited purposes, single-case experimentation has proved to be a vital source of strength in the development and evaluation of behavior modification, and that it might be equally useful in the experimental study of other psychotherapy approaches. (26 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Advanced regression methods for single-case designs: Studying propranolol in the treatment for agitation associated with traumatic brain injury.

Objective: The use of single-case designs in intervention research is discussed. Regression methods for analyzing data from these designs are considered, and an innovative use of logistic regression to analyze data from a double-blind, randomized clinical trial of propranolol for agitation among persons with traumatic brain injury (TBI) is used. Method: Double-blind, randomized clinical trial performed in an outpatient rehabilitation setting. Participants: Nine men and 4 women with TBI. Results: Logistic models indicated that propranolol was not associated with less agitation for most participants (Φ=-.135; 90% exact confidence interval was -.03     

A paradigm for single-case research: The time series study of a long-term psychotherapy for depression.

Articulates a paradigm for single-case research in psychotherapy. A patient diagnosed as having major depressive disorder was seen in an intensive, twice-weekly psychodynamic psychotherapy for 2.5 years. Each session was videotaped, and assessments of patient change were obtained at regular intervals. A time-series analysis was used to model fluctuations in the therapy process to take into account time and the effect of previous events on subsequent changes, thereby preserving the context-determined meaning for therapist and patient actions. A bidirectional analysis of causal effects shows that the influence processes between therapist and patient are mutual and reciprocal and suggests that the effect of the patient on the therapist and on the process has not been made sufficiently explicit in previous models of process and change. The potential of intensive single-case designs for uncovering causal effects in psychotherapy is demonstrated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controlling baseline trend in single-case research.

School psychologists commonly conduct interventions for individual students and evaluate their success through single-case research designs, most of which include a baseline observation period. However, concluding intervention effectiveness from a single-case design is problematic when pronounced baseline trend is evident. With positive baseline trend, interpretation of the measured mean difference between phases is ambiguous, and an invalid interpretation is probable. Although an adequate method for controlling baseline trend exists, it is rarely applied in published studies. This article seeks wider application of baseline trend control by describing a modified technique that blends more easily with visual analysis. A second goal of this article is to encourage better informed use of baseline trend control, by empirically demonstrating its need in published studies, and its impact on R2 effect sizes and on autocorrelation. Finally, baseline trend control is combined with elimination of autocorrelation, for results that can withstand the scrutiny of the broader research community. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methodological and interpretive problems of single-case experimental designs.

Considers methodological and interpretive problems that frequently arise in single-case experiments. These designs are uniquely suited to evaluating treatment effects with individual clients. Although treatment is evaluated by comparing baseline and treatment phases, the manner in which this is accomplished varies as a function of the specific design. Typically, the comparison is replicated over time (ABAB design) or across different behaviors (multiple-baseline design). Several methodological problems frequently arise in single-case designs, such as deciding when to alter phases or conditions in the experiment, ensuring that the intervention is implemented, comparing alternative treatments unconfounded by sequence effects, and ensuring that data are collected reliably. Many interpretive problems of single-case designs stem from the criteria used to evaluate treatment. The ambiguity of these criteria, relative to statistical tests used in group designs, presents unique problems for evaluating treatment. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrating psychotherapy research and practice: Modeling the change process.

Identifies factors responsible for the slowness over the years of psychotherapy researchers to utilize intensive analysis procedures. These factors include the uncritical utilization of conventional research methodologies, the failure to distinguish between different types of intensive analysis designs, the assumption that intensive analysis is necessarily unscientific, and the fact that the behavioral single-case experimental design is inappropriate for studying other forms of therapy. The task-analysis approach to psychotherapy research is presented as a methodologically rigorous alternative to the behavioral single-case experimental design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Critical issues in cognitive remediation.

Describes cognitive remediation (CGR) as a rehabilitation intervention that gained momentum in the early 1970s when a group of investigators at New York University Medical Center began a series of systematic studies to examine the learning styles of brain-damaged patients and to determine if their cognitive deficits were amenable to treatment. Although CGR is widely applied to individuals with brain injury, insufficient large-scale research has been conducted supporting its efficacy. Several principles that underlie successful CGR are discussed. These include (1) the existence of a logical basis for the ordering of treatment, (2) generalization as the goal and outcome of CGR, (3) psychotherapy as a mediator of successful CGR, and (4) the need to modify existing methodologies to assess treatment efficacy. The use of single-case experimental designs is suggested as a means of expanding the literature on the utility of CGR. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single-case design: A primer for play therapists.

Play therapy research is typically presented to practitioners as extensive and detailed studies that involve excessive controls of variables and large numbers of subjects in order to generalize findings. However, single-case design is one research design that involves concentration on data collection from few participants and involves clinical decision-making of the play therapist. This article defines single-case design and provides step-by-step suggestions for how to conduct a single-case design study. We also provide a specific example of single-case application to play therapy intervention and further discuss common problems in play therapy single-case design implementation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The education and training of clinical psychologists in the Netherlands.

With the reduction of the doctorandus program in the Netherlands to 4 yrs, a graduate program has been created that is significant to clinical psychology because it separates the research and applied orientations. The research orientation leads to the PhD, the applied orientation to a certificate of professional registration. This distinction has effectively ended the scientist–practitioner model underlying the training of clinical psychologists. In moving clinical psychology from its scientific research base, psychology has become more fragmented, and in a way that has far-reaching implications for the discipline and the profession in the Netherlands. These developments are of interest due to the debate in the US and elsewhere on training and licensure of clinical psychologists and concern about the unity of psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On Construct Validity: Issues of Method and Measurement.

Fifty years ago, L. J. Cronbach and P. E. Meehl (1955) advocated for the concept of construct validity, noting that psychologists study hypothetical, inferred entities and that validating measures of such entities involves basic theory testing. Three important developments in clinical assessment following that seminal article are noteworthy. First, clinical research has benefited from greater theoretical integration and subsequent differentiation among related constructs. Second, implementation of ongoing, critical evaluation of all aspects of the construct validity process, including theory development, hypothesis specification, research design, and empirical evaluation, has improved clinical assessment. Third, improvement in evaluating fit between hypotheses and observations has been sought. Improved means of evaluating multitrait, multimethod designs, and ways to increase their clinical representativeness, are one encouraging development. Ongoing efforts to improve the construct validity process reflect the legacy of L. J. Cronbach and P. E. Meehl. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A daily process approach to coping: Linking theory, research, and practice.

For decades, coping researchers have used between-person designs to address inherently within-person questions derived from theory and clinical practice. The authors describe recent developments in the use of within-person, process-oriented methods that examine individuals intensively over time. Ongoing studies of stress and alcohol consumption, the effects of depression on adaptational processes, and the temporal dynamics of coping with chronic pain demonstrate that by tracking rapidly fluctuating processes such as mood and coping close to their real-time occurrence, daily process designs offer unique insights into conceptually and clinically challenging questions. Such designs also provide new opportunities to examine the purported mechanisms of therapeutic interventions. Despite its demands on participants and investigators, daily process research offers fresh opportunities to link psychological theory, research, and practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-sectional time-series experiments: Some suggested statistical analyses.

In the past, statistical analyses for time-series experiments have usually operated with a single-case model, thereby limiting the general applicability of the designs. In this article, alternative analytical procedures are developed for cross-sectional time-series in which the sample size is large and the number of observations per case is relatively small. Interrupted time series, equivalent time samples, and multiple time series are all treated within a multiple regression framework. A generalized least squares estimation procedure is outlined as a more suitable alternative to the G. E. Box and G. M. Jenkins (1970) approach. Some of the special advantages of the designs are briefly discussed. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Generalized single-case randomization tests: Flexible analyses for a variety of situations": Erratum.

Reports an error in "Generalized single-case randomization tests: Flexible analyses for a variety of situations" by Joel R. Levin and Bruce E. Wampold (School Psychology Quarterly, 1999[Spr], Vol 14[1], 59-93). (1) In Table 5 (p. 76), in the cell associated with the third row and third column, the upper value of 18.3 should be 18.73. (2) On p. 81, in the section titled "Simultaneous Start-Point Randomization for Matched Pairs of Units," the sentence beginning in line 10 should read: "With k? acceptable start points for the first pair and k? for the second, there would be k?k? summed sums and null hypothesis-compatible summed differences for the randomization distribution to test Rgen and Rcomp, respectively (as indicated in the Appendix, p. 89)." (The following abstract of the original article appeared in record 1999-10944-004.) A general class of single-case statistical procedures, derived from previously developed nonparametric randomization tests, is presented. These procedures are widely applicable in behavioral and educational research contexts in which only a few experimental "units" (individuals, small groups, or classrooms) are the recipients of one or more experimental treatments or interventions. Specifically illustrated are designs that focus on both the general and comparative effectiveness of alternative interventions (including control/placebo treatments), multiple units with differentiable characteristics (i.e., intervention by unit characteristic interactions), and multiple outcome measures (i.e., intervention by outcome measure interactions). Also provided are operational modifications that enhance the internal validity of studies incorporating single-case randomization-based analyses. Appropriate cautions and issues surrounding the use of these procedures are included. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Research and psychoanalysis: Still time to bridge the great divide?

The interface between psychoanalysis and scientific research has been characterized by controversies and polarizations that have made a constructive debate very difficult. It is argued that the roots of the controversies are better understood as stemming from an uncompromising position within the psychoanalytic field that holds that scientific research and psychoanalysis are inherently incompatible and that the only research admissible is one that takes place within the psychoanalytic encounter. A critique of this rejectionist position, still tenaciously held by a sizable minority within the psychoanalytic community, is offered, and the repercussions of adhering to such view are discussed. It is argued that the theoretical fragmentation present in psychoanalysis has mostly stemmed from the sole reliance of a theory formation based on the single-case clinical study and that the refusal to engage in scientific studies has contributed to the progressive decline that psychoanalysis has been suffering over the last 20 years. Integration of scientific research with psychoanalytic practice and building bridges with other neighboring disciplines such as psychology, psychiatry, and neuroscience may help reestablish psychoanalysis as a relevant discipline in the university and mental health field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Three CAG trinucleotide repeats on chromosome 6 (D6S1014, D6S1015, and D6S1058) are not expanded in 30 families with schizophrenia

Despite its importance and widespread usage, the term mixed dementia, referring to the coexistence of Alzheimer's disease (AD) and vascular dementia (VsD), has been ill-defined and poorly conceptualized. The authors review the use of the term mixed dementia in neuropathological and clinical research. As a result of recent developments in the categorization of dementias, they recommend discarding the term mixed dementia in favor of a more precise terminology based on AD and VsD concurrently meeting established criteria for each diagnosis.     

Reexamining guiding assumptions: Theoretical and methodological implications.

Analyzes articles by D. E. Polkinghorne (see record 1985-07630-001), G. S. Howard (see record 1985-07626-001), and M. J. Patton (see record 1985-07629-001), in terms of their assumptions concerning the nature of human beings and appropriate research methods in counseling psychology. They emphasize 4 sets of variables: intentionality, cognitive processes, consciousness, and talking behavior. They argue that the person in their social context should be the primary unit of analysis and that humans must be understood as active, self-constructing, goal-directed organisms. Replicated single-case designs are recommended as research methodology. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)