It turned out that Vesanto’s SOM toolbox for Matlab is very well written and works right out-of-the-(tool)box. It’s advisable to read the documentation and the technical report (.pdf). And it’s really worthwile to try one of the matlab examples which is some kind of tutorial on how to work with the SOMs.
Yesterday I received an email from Tobias Günther, who defended his PhD thesis recently. It was about Data mining in diagnostic charts and treatment outcome prediction for Vision Restoration Therapy and he used SOMs throughout his work, namely the above toolbox. His full thesis is also available at our University library.