Developing an annotated corpus of patient histories from the primary care health record

We have developed a tool for annotation of electronic health record (EHR) data. Currently, we are in the process of manually annotating a corpus of Norwegian general practitioners EHRs with mainly linguistic information. The purpose of this project is to attain a lingustically annotated corpus of patient histories from general practice. This corpus will be put to future use in medical language processing and information extraction applications. This paper outlines some of our practical experiences from developing such a corpus and, in particular, the effects of semi-automated annotation. We have also done some preliminary experiments with part-of-speech tagging based on our corpus. The results indicate that relevant training data from the clinical domain gives better results for the tagging task in this domain than training the tagger on a corpus from a more general domain. We are planning to expand the corpus annotations with medical information at a later stage.