Artificial neural networks- a tool for clinical decision: a computerised mathematical model for understanding and predicting complex and chaotic dynamics in complex biological systems. A type of artificial intelligence that attempts to imitate the way a human brain works. Rather than using a digital model, in which all computations manipulate zeros and ones, a neural network works by creating connections between processing elements, the computer equivalent of neurons. The organization and weights of the connections determine the output. Neural networks are particularly effective for predicting events when the networks have a large database of prior examples to draw on.