Towards Multiword Expression Analysis for Logic-based Medical Case Retrieval

Abstract

Temporal relation recognition between events in clinical texts is a challenging and valuable task. To realize medical information retrieval for a time-series event, we propose a method to perform inferences over temporal relations in the medical domain using ccg2lambda, an integrated system that maps a sentence to a higher-order logical formula by syntactic analysis and semantic composition based on Combinatorial Category Grammar (CCG). However, current ccg2lambda does not parse multi-word expressions in clinical texts. To solve this issue, we add a multi-word expression analysis module to ccg2lambda. We construct a dataset annotated with the semantic relations of multi-word expressions in clinical texts and implement a multi-word expression analysis module using BiLSTMs. Our enhanced ccg2lambda with a multi-word expression analysis module enables us to correctly map some sentences in clinical texts to their semantic representations.