No kidding. Here is another shocker and you can quote me on this - it is not possible to diagnose anosognosia in stroke patients based on a brain scan. Quoting an expert: "Anosognosia refers to the lack of awareness, misbelief, or explicit denial of their illness that patients may show following brain damage or dysfunction. Anosognosia may involve a variety of neurological impairment of sensorimotor, visual, cognitive, or behavioral functions, as well as non-neurological diseases." I encourage anyone who is interested in this topic to find a copy of this book chapter listed in the references below. The author thoroughly discusses the fascinating history of this disorder, specific protocols used to make the diagnosis, various neurological subtypes with heterogeneous lesions and the fact that no specific mechanism has been determined.
In a more recent article available online, Starkstein, et al provide an updated discussion in the case of stroke. They discuss it as a potential model of human awareness, but also point out the transient nature and difficulty in developing research diagnostic criteria. They provide a more extensive review of instruments used to diagnose anosognosia and conclude: "Taken together, these findings suggest that lesion location is neither necessary nor sufficient to produce anosognosia, although lesions in some specific brain areas may lower the threshold for anosognosia. Strokes in other regions may need additional factors to produce anosognosia, such as specific cognitive deficits, older age, and previous strokes."
The experts here clearly do not base the diagnosis of this syndrome on imaging. It is based on clinical findings. For anyone interested in looking at the actual complexity in the area of anosognosia in schizophrenia I recommend reading these free online papers in the Schizophrenia Bulletin in an issue that dedicated a section to the topic in 2011. You will learn a lot more about it than reading an anti-biological antipsychiatry blog. But of course you need to be able to appreciate that this is science and not an all or none political argument.
George Dawson, MD, DFAPA.
Patrik Vuilleumier. Anosognosia in Behavior and mood disorders in focal brain lesions. Julien Bogousslavsky and Jeffrey L. Cummings (eds), Cambridge University Press 2000, pp. 465-519.