Assessment and measurement in neuropsychiatry: a conceptual history

Since the time the parent discipline of psychiatry became organized as a profession, one of its ludi saeculares (neuropsychiatry) has enjoyed at least 4 vogues. On each, neuropsychiatry has been known to ally itself to a cause: currently it is the big business of neurobiology. This move can be seen as scientific progress or as a side-effect of the (professional rather than scientific) infighting that affected neuromedicine during the late 19(th) century and which led to the construction of the notion of "neurological disease." Alienists responded to this variously: some, like Kahlbaum and Kraepelin accepted the split and returned to the more botanico approach; others, like Ziehen chose psychology; yet others, like Freud, delved in hermeneutics; lastly, there were those, like Meynert, Wernicke, Von Monakow, and Liepmann who sought an accommodation with neurology. Born out of this compromise, neuropsychiatry has remained a blurred activity (whose definitions range from "psychiatry of neurology" to a crusade for the "naturalization of the mind"). Neuropsychiatric assessment is a methodology designed to collect information about patients whose mental symptoms are thought to be caused by brain disease. When it first appeared, it was torn by the debate between "nomothetic versus idiographic" science. For a time, the neuropsychiatry assessment techniques stuck to the old personalized narratives characteristic of 19(th) century "casenotes" (trying to meet its descriptive, explanatory, therapeutic, legal, and ethical obligations). But during the late 19(th) century, measurement and quantification became part of the new rhetoric of science. Soon enough this affected psychology in general and neuropsychology in particular and neuropsychiatric assessment followed suit. It has changed little since except that now and again old tests and markers are replaced by more "reliable" ones and phenomenological data are squeezed out further. Its laudable enthusiasm for objectivity and truth was ab initio justified by 19(th) century Positivism; currently, it seems to be supported by a naïve version of Popperian falsificationism. In the meantime, the scientific worth of the neuropsychiatric assessment remains unclear; indeed, in an age of evidence-based medicine, it is surprising that both its informational and communicational value and its efficiency as a general epistemic tool have not been subjected to any serious empirical testing.