Scandinavian journal of gastroenterology. Supplement
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The limitations of conventional group comparative therapeutic trials are discussed. They include: the heterogeneity problem (due to biological variations within the sample) and the extrapolation problem (i.e. the problem of external validity). These problems may to some extent be overcome by multiple cross-over studies in a single patients. ⋯ Usually, it is necessary to measure the clinical effect by means of clinical scores, for which reason ranking methods must be used. The statistical significance may be judged by means of a permutation test. The risk of committing a type II error in single patient studies is usually high.
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Scand. J. Gastroenterol. Suppl. · Jan 1988
Comparative StudyAn N of 1 service: applying the scientific method in clinical practice.
The N of 1 service at our institution acts as a full referral service for clinicians who want a definitive answer to a difficult management question, and an instructional environment for clinicians who have more time and want to learn to run their own N of 1 RCT. The trial design is a double blind, randomized pair, multiple crossover. ⋯ The analysis issues include developing a reporting method which is statistically powerful and understandable to clinicians with little research background. Some of these issues have been well investigated and some have not.
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'Gastro-esophageal reflux' is the passage of gastric content into the esophagus. Resulting typical symptoms are denoted as 'reflux like dyspepsia'. 'Reflux esophagitis' is the endoscopic or microscopic evidence of damage to the esophageal mucosa. ⋯ Esophageal acid exposure increases during the day with a peak in the evening and little reflux after midnight. Treatment should probably be concentrated to evening time and not so much to night time.
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Scand. J. Gastroenterol. Suppl. · Jan 1988
Review Comparative StudySingle case studies in psychology and psychiatry.
Single-case experimental designs are presented and discussed from several points of view: Historical antecedents, assessment of the dependent variable, internal and external validity and pre-experimental vs experimental single-case designs. In addition, general characteristics of experimental single-case designs are presented along with examples of the most common design types. ⋯ It is argued that single-case experimental designs are well suited for medical research as well as clinical practice. They provide tools for testing causal hypotheses concerning the effects of interventions in the single case.
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Scand. J. Gastroenterol. Suppl. · Jan 1988
Comparative StudySingle case studies in clinical trials.
The single case design offers an interesting alternative to standard methods of performing clinical trials. The opinion of the workshop members was that single case trials would be particularly useful in studies of rare diseases and in studies aimed at generation of hypothesis rather than testing of hypotheses. The single case design was considered to require smaller patient materials than ordinary methods in order to arrive at a valid conclusion about therapeutic effect. Dose ranging (Phase II) studies and studies of heterogenous patient populations were also discussed as possible areas of application for the single case design.