Tuesday, November 13, 2012

A Semantic Network of Patient Data

This idea has two inspirations. One is this TED talk by Dave deBronkart or "e-Patient Dave". The other is the work that has been done on the semantic web and linked data.

Dave's talk is about patients taking control of their medical records and sharing them with other like-minded patients, so that they can learn from one another's histories and experiences. Some of these patients, including Dave, had terminal diagnoses and were able to improve or resolve those conditions because of having shared data with others.

The semantic web is the idea of formatting information so that computers can do more with it than simply store it or transmit it or display it on a screen. Computers can understand the meaning of the information much as a human would, so they can reason about it and draw new conclusions that aren't already spelled out. I first learned about it in a 2001 article in Scientific American. There are some more details here. I've blogged in the past about some of the basic ideas.

In the semantic web, all "things" (nouns, basically) are assigned URIs (web addresses). Relationships between things (and relationships are also things) are represented as RDF, where every statement is a triple of URIs, being a subject, predicate, and object. These statements are often printed or transmitted in XML, but the N3 language is more readable for people. Typical relationships look something like this.
  Will, town, "Framingham MA".
  Will, name, "William Ware".
  Will, pet, cat#12345.
  cat#12345, name, "Kokopelli".
  cat#12345, birthyear, 2003.
Strings ("William Ware", "Kokopelli") and numbers (2003) can be raw data, everything else is a URI. The idea is that a URI connects you to the rest of the semantic web of meaning, so if you don't know what a "pet" is, you can follow that URI, or query other triples with "pet" in them, to find out more.

You might wonder if it's silly to have such a primitive representation for knowledge. It allows the same kinds of economies of scale that we get by representing information in a computer with ones and zeroes. Because the format is so simple and uniform, we can build processing architectures that can be very efficient, and people have been doing that for over ten years. We have scalable databases for RDF, and when we set up rules that mimic set theory, we can build reasoning engines that extract new conclusions from the data.

When data is formatted with an appropriate ontology, it can be searched in rich complex ways, and computers can look for patterns and correlations that a human might not notice. When applied to patients' medical data, the results might be new medical knowledge or new treatment options.

There are other ways to find new information hidden in patient data. Semantic web technology is great for pure logic, but for quantitative measures (a dosage increase in this medication seems to cause a decreased amount of that neurotransmitter) we can turn to machine learning, where progress in the last decade or two has been explosive, given the data available on the web and the economic rewards for finding patterns in it.

An idea I've blogged about in the past (and spoken about at a couple of very small conferences) is applying this to general scientific literature, with the goal of hastening scientific progress and in particular medical progress (since I'm an old fart now and interested in that sort of thing).

If this topic interests you and you wish to discuss it, I'm starting a Google Groups forum for that purpose.

UPDATE: I've discovered that there is a company in Cambridge, MA called PatientsLikeMe which already pools patient data into a database, and sells subscriptions to that database. I don't know if they place the same emphasis on machine-tractable formats that I've done above. But knowing that somebody is doing it on a commercial basis, I don't see much point in trying to replicate that effort in my evenings and weekends.

No comments: