Alzheimer’s: Portrait of an Epidemic (2001)
by David Shenk (1967?-)
I read this book more quickly than any other I have read in a long time, so it must have been very interesting. Shenk has been inspired to address this subject – he says the book chose him. His interest shows.
Shenk, a reporter, approaches the subject by way of examples, some contemporary anonymous sufferers and their caregivers, and some famous historical and literary figures. In the latter category, Ralph Waldo Emerson, Jonathan Swift, and King Lear are prominent.
I was alerted to this book by an NPR interview. I was particularly interested in his comment that in understanding the forgetting at the heart of Alzheimer’s, he had to learn what memory is. Of course, this is central to my interest, too. His description of the constellation theory is fairly coherent, if brief. He quotes Daniel Schacter (summarizing the explanation):
A typical incident in our everyday lives consists of numerous sights, sounds, actions, and words. Different areas of the brain analyze these various aspects of an event. As a result, neurons in the different regions become more strongly connected to one another. The new pattern of connections constitutes the brain’s record of the event.
He also mentions that recalling a memory results in a memory of a memory. The common aspects of an original memory and the memory of recalling it result in a strengthened memory, streamlined and dropping the less-relevant (to the recollection event) aspects of the original memory.
The description of the theory of memory was my primary reason in obtaining the book, but I found the descriptions of the nature of Alzheimer’s disease interesting in its own right. Although the explanation could have benefited from a few pictures showing the relationships among parts of the brain’s anatomy and their functions, it was fairly clear.
After describing the sequence of symptoms from early to late stages, Shenk describes the corresponding progress of cellular destruction beginning in the hippocampus (disrupting the formation of new memories), and spreading through the amygdala (resulting in inappropriate primitive emotions of rage, anxiety, and craving), and the temporal (organization of sensory input, processing language, and ecstatic feelings of transcendence, leading to visual and auditory hallucinations), parietal (touch, vibration, pain, spatial awareness, leading to isolation of the patient from the world of touch), and frontal (retrieval of already formed memories, and loss of identity) lobes.
Comparison of the stages of progression of Alzheimer’s with the stages of development from infancy to puberty shows a near-exact (in this summary) reversal. The course of myelinization that brings parts of the brain on-line is the same order that cells are lost to the tangles and plaques that destroy the neurons.
Shenk describes some of the research results of recent years, and mentions some optimistic findings. However, this is not his purpose. Rather, he want’s to show how awareness of the nature of the disease, and the manner in which victims and their caregivers react to it, illustrate the nature of humanity. I am not so sure he succeeds in this, but it is an interesting notion. Certainly many of his descriptions are affecting.