Wednesday, February 26, 2020

The Island of the Colorblind by Oliver Sacks

Source of book: Borrowed from the library

It has been a couple of years since I read an Oliver Sacks book, and I needed a beach read (yes, we go to the beach in the winter here in California…), so I picked this one up. I previously read and reviewed Musicophilia

Sacks was a neurologist, writer, researcher, teacher, and (in his spare time), a pianist. His books cover a fairly wide range of neurological topics, and reveal Sacks to have an astonishingly wide range of knowledge. He seems to know a little about everything, to observe everything, and relish knowledge for its own beauty. There are a lot of examples in this book and the other, where he realizes he has an interesting tidbit that doesn’t fit neatly in the narrative, so he puts it in a long endnote. (There are over sixty pages of endnotes in this book, most of which follow interesting “rabbit trails” related to details in the main body of the book. Definitely read these!) Sacks is also such a music fan, he can’t help working musical references in. In the introduction, he mentions that his soundtrack for writing the book was Tobias Picker’s The Encantadas, a work for orchestra and narrator - with words from Herman Melville’s account of his visit to the Galapagos. 

Rather than write a treatise about a topic, Sacks tells stories. Stories about his patients, stories about his research, stories about friends and family, and so on. This is a big reason why Sacks’ books are so much fun. He really cares about and enjoys people, and his empathy really shows. 

The Island of the Colorblind is about two different trips Sacks took to Micronesia. In each case, he was learning about and researching a particular disease which was endemic to a particular area. 

The title of the book is drawn from the first trip, which constitutes the first half of the book. The island of Pingelap is home to a concentration of people who have a type of colorblindness called congenital achromatopsia. This is a genetic condition that is total colorblindness. Unlike the more common form, where reds and greens get confused, this condition is characterized by a total inability to see color at all. The condition has other, rather unpleasant, symptoms, such as an inability to see clearly in bright light, involuntary eye movements, and poor visual acuity. Unlike the more common red/green colorblindness, achromatopsia is not a sex-linked genetic defect - it is equally common in men and women. 

Achromatopsia is quite rare in most places in the world - Sacks finds two individuals with it who assist him in his research, neither of which had actually met anyone else with the condition until later in life. However, on Pingelap, it affects about a third of the residents. Why is this so? Well, islands are somewhat isolated. In the case of Pingelap, about 200 years ago, the island was nearly destroyed by a hurricane, and there were only a few dozen survivors. With this limited of a gene pool, the recessive gene for achromatopsia spread throughout the population. How it got there is unknown, but it seems plausible that one of the explorers/colonizers from the past had the mutation, and left it behind in the gene pool sometime before the hurricane. 

Sacks travels to Pingelap (and a few nearby islands) with Knut Nordby, a Norweigian scientist with achromatopsia. Knut is able to greatly add to the expedition’s success because of his own experience (which aids in knowing how and what to test) and the natural bond that develops between him and others with the condition - they literally can recognize each other at a distance. 

While the research is the main theme, there are plenty of other incidents and details which are fascinating. Sacks seems to make friends wherever he goes, and gets as much out of the experience as possible. From the local food to the plant life, Sacks makes the islands come alive. Perhaps this is because, as the first few pages indicate, Sacks is fascinated with islands. 

The trip wasn’t all business, either. Sacks and Knut are taken by boat to the far side of Pohnpei to see the ruins of Nan Madol. I admit, I had never heard of the place before reading this book, so I had to look it up. Apparently, it is one of the wonders of the world, and thoroughly mysterious. The only ancient city built on coral reefs, it is believed to have been the capital of an extensive empire. It was constructed largely of giant basalt columns, similar to those found at Devil’s Postpile. Somehow or other, these gigantic rock columns - which weigh many tons - were transported from the other side of the island - which is about the size of New York City. They were then assembled log-cabin style into massive structures which have survived mostly intact for hundreds of years. All food and water had to be brought in by boat, which implies an extensive supply network. And then, about 350 years ago, it was abandoned. Anyway, if you want to read more about it, this Smithsonian article is interesting. 

The second half of the book concerns a trip to Guam, to research lytico-bodig disease - a form of ALS with other complications (parkinsons, dementia, other neurological symptoms) - that occurred with great frequency on the island of Guam. “Occurred” in the past tense is the best way to describe it, because, as of the mid 1990s, when Sacks visited, the condition appeared to only occur in people born before 1952. 

The cause of this disease has been a longstanding mystery, although there is now a promising theory. When Sacks wrote the book, he had to concede that efforts to discover the cause and mechanism had failed - and that it might never be found, because new cases in younger people were not occurring. 

The theories were many, but they had all, after extensive research, failed to prove true. The most likely seemed to be a connection to the consumption of cycad seeds. These were known to be toxic, but could have the toxin leached out. Also, the cycad connection failed to explain why younger people were apparently immune from the disease, despite eating cycad. Was it an increased consumption during World War Two? Was there a genetic component? That theory didn’t pan out, as there was no statistically significant genetic pattern. If anything, the pattern followed families, not genetics, which implied some environmental toxin or pathogen. 

Sacks didn’t end his research with the book, however, but continued to look into the issue. In 2002, he published a paper along with Paul Alan Cox on their theory that the cause was a toxic amino acid which was indeed connected with cycads. However, it was actually from a cyanobacteria that lives symbiotically with cycads. This bacteria was then ingested by a flying fox, and then concentrated in the nerve and brain cells of that creature. These were then eaten by humans, allowing a dose far greater than that of eating cycad seeds. I can’t find a free version of that 2002 paper, but you can read more recent detail on that in this paper by Cox and others in 2003, and this paper from 2012 which looks more broadly at cyanobacteria toxicity. It is fascinating stuff.

In the course of the discussion, Sacks goes off on a tangent about the history of cycads - one of the most ancient plants. His fascination with them goes back to his childhood. (He’s like this about everything - he loves it all and wants to tell you all about it!) 

One thing that stood out to me that Sacks observed in Guam was that the more family-oriented culture adapted far better to progressive neurological disease than our own Western cultures have. Caretaking is both normal and a community endeavor. Nobody complains about caring for family or neighbors. It just gets done, and is accepted as part of life. It is a far cry from our own tendency to go all “every man for himself” whenever something uncomfortable or unpleasant happens to someone else. It is a reminder that there is nothing inherently superior about our own culture. Like every culture, it has its strengths and weaknesses. And there is nothing magical about a particular moment in the past either. Circumstances change, cultures change, and our best bet is to try to make what we have the best and kindest it can be. 

I selected this book (out of the many Sacks books) by the fact that it happened to be checked in at the time - I needed a book for the next day. But, I have come to believe that there is no such thing as a disappointing Oliver Sacks book. No matter the topic, his vast knowledge, his ear for a compelling story, and his compassionate and empathetic approach to life combine to make a thoroughly enjoyable experience. 

No comments:

Post a Comment