Reference: Ohno-Machado, L. & Musen, M. A. Modular Neural Networks for Medical Prognosis: Quantifying the Benefits of Combining Neural Networks for Survival Prediction. Knowledge Systems Laboratory, Medical Computer Science, February, 1996.
Abstract: This paper describes a medical application of modular neural networks for temporal pattern recognition. In order to increase the reliability of prognostic indices for patients living with the Acquired Immunodeficiency Syndrome (AIDS), survival prediction was performed in a system composed of modular neural networks that classified cases according to death in a certain year of follow-up. The output of each neural network module corresponded to the probability of survival in a given year. Inputs were the values of demographic, clinical, and laboratory variables. The results of the modules were combined to produce monotonic survival curves for individuals. The neural networks were trained by backprogation and the results were evaluated in test sets of previously unseen cases. We showed that, for certain combinations of neural network modules, the performance of the prognostic index, measured by the area under the receiver operating characteristic (ROC) curve, was significantly improved (p<0.05). We also used calibration measurements to quantify the benefits of combining neural network modules, and show why, when, and how neural networks should be combined for building prognostic models.