Chapter 16 - Single Cases, Group Studies and Case Series in Aphasia Therapy

Abstract

This chapter explores the single cases, group studies, and case series in aphasia therapy. In neuropsychology the case for single case studies has been discussed. There are a large number of possible patterns of acquired cognitive impairment. The results of a set of participants can only be meaningfully combined if they suffer from the same underlying impairment(s). The chapter describes that to conduct a meaningful group study it is necessary first to establish that the participants have the same underlying disorder. This can only be done on the basis of studying each as a single subject. Furthermore, participants cannot be grouped on the basis of surface symptoms because these may reflect different underlying disorders. The disadvantage of single case studies is that it seeks to establish a set of facts that are true just for a single participant. It cannot be generalized to other participants. Case series designs of therapy can be used to identify which patients benefit from a single well-specified therapy. Supported by proper use of homogeneity tests, it is possible to address the null hypothesis that treatment gains are equal for all the participants. It can be used to test specific accounts of how therapies operate. Where the participants are a random sample from a particular population the results can be generalized to that population. There seems to be no reason of widely adopting this approach.