Defining 'normal': Methodological issues in Aphasia and intelligence research

Theodore H. Weisenburg (1876-1934) and a series of colleagues embarked on a research program in 1927 to develop standardized tests to investigate the nature of language and intellectual impairments in aphasic and non-aphasic individuals. This project culminated in two significant contributions to neuropsychological testing (Weisenburg & McBride, 1935; Weisenburg, Roe and McBride, 1936). After an initial study demonstrated the prob-lematic aspects of Henry Head's aphasia tests (1926), Weisenburg developed a new battery of tests which were given to individuals with aphasia. The significant innovation of this work was the original concept of a matched control group. This included those with other neurological impairments, and a range of non-neurologically impaired individuals with the aim of providing a characterization of what was 'normal'. They identified many crucial participant variables regarding age, education, and socioeconomic status and used popu-lation statistics to ensure their control sample was representative. A detailed critical assessment of each of their successive elaborations is examined, focusing on the meth-odological innovations they represent. The contribution of this work to contemporaries and successive generations of neuropsychologists is examined regarding ongoing issues in clinical testing and research design. (c) 2022 Elsevier Ltd. All rights reserved.