The dementia seen in Alzheimer's patients is the manifestation of severe neurodegeneration - brain cell death. Classically, Alzheimer's has been diagnosed only after death by two characteristic sorts of lesions in the brain: plaques and tangles. Decoding Darkness tracks the development "clue by clue" of the amyloid hypothesis, the view that the amyloid protein deposits (or plaques) in the brains of Alzheimer's sufferers are somehow directly responsible for the disease's characteristic neurodegeneration. Drug therapies based on this hypothesis are currently in various stages of development.
Decoding Darkness is a well-balanced mixture of scientific detection and autobiography. Rudolph Tanzi has been involved in the search for the genetic basis of Alzheimer's disease since the 1980's, and is currently director of the Genetics and Aging Unit at Massachusetts General Hospital. Ann Parson is a science journalist. Their clear account of the development of the amyloid hypothesis and its implications for the treatment of (and even vaccination against) Alzheimer's, will be of interest to anyone touched by the disease. The depth of explanation, and Tanzi's obvious excitement in the research should also make Decoding Darkness a good choice for any reader interested in Alzheimer's, the genetic basis of disease, or even just modern developments in molecular genetics. Some of the technical material is rather dense, but should be accessible if some care is taken over original definitions and explanations.
On the scientific front, all that I felt was lacking was a more adequate picture of the rival to the amyloid hypothesis - the tangle theory. Tangle theorists hold that the other characteristic brain lesion seen in Alzheimer's - the neurofibrillary tangle - is responsible for brain cell death. The theme of fierce competition between scientists (or teams of them) is brought across so well in the book that this lack is immediately noticed; a comparison may have increased the reader's sense of getting an objective portrait of the current state of Alzheimer's research.
To be fair, though, a lot of Decoding Darkness's charm and interest lies in its subjectivity. We are offered an insight into the motivations of the researcher through "Rudy" (you can't help liking him) Tanzi's life story. What I found fascinating was Tanzi's attitude to the aforementioned scientific competition. For non-scientists and wannabe scientists the world of funding battles can seem like a pretty scary and depressing place, perhaps the worst of it being that results (treatments! cures!) might be held up because sharing just doesn't pay off. For Tanzi though, the challenge of "the horse race" seems to be one of the things that keeps him going. Reading Decoding Darkness, one gets more of a sense of teams driving each other on than cutting each other's throats. Though not yet convinced of Tanzi's rosy view, I ended up with a better understanding of how a scientist derives pleasure from a job whose goals can seem so far away.
Don't go looking for deep consideration of the ethical issues involved in molecular genetics in Decoding Darkness. But I happen to agree with the authors' brief comments (No, bombing people because of their scientific beliefs is not right; yes, there should be more thought put into the use of e.g. transgenic mice in research) so I didn't see this as a serious flaw. One book cannot be all things to all people. As a disclaimer, I have to admit that I'm probably the perfect target audience for this book (fascinated by Alzheimer's, basic genetics background, love detective stories). That said, I learned a great deal about Alzheimer's disease and modern genetic research from Decoding Darkness, and enjoyed it as well.
© 2001 Aislinn Batstone Aislinn Batstone is a Ph.D. candidate at Macquarie University, Sydney. Her research interests include metaphysics, philosophy of logic, and the philosophy of neurobiology and mental illness.