A new method for sleep apnea classification using wavelets and feedforward neural networks.
OBJECTIVE
This paper presents a novel approach for sleep apnea classification. The goal is to classify each apnea in one of three basic types: obstructive, central and mixed.


METHODS
Three different supervised learning methods using a neural network were tested. The inputs of the neural network are the first level-5-detail coefficients obtained from a discrete wavelet transformation of the samples (previously detected as apnea) in the thoracic effort signal. In order to train and test the systems, 120 events from six different patients were used. The true error rate was estimated using a 10-fold cross validation. The results presented in this work were averaged over 100 different simulations and a multiple comparison procedure was used for model selection.


RESULTS
The method finally selected is based on a feedforward neural network trained using the Bayesian framework and a cross-entropy error function. The mean classification accuracy, obtained over the test set was 83.78+/-1.90%.


CONCLUSIONS
The proposed classifier surpasses, up to the author's knowledge, other previous results. Finally, a scheme to maintain and improve this system during its clinical use is also proposed.
Fontenla-Romero
Oscar
O
Department of Computer Science, Faculty of Informatics, University of A Coruña, Campus de Elviña s/n, 15071 A Coruña, Spain. oscarfon@udc.es
Guijarro-Berdiñas
Bertha
B
Alonso-Betanzos
Amparo
A
Moret-Bonillo
Vicente
V
D000465:Algorithms; D001499:Bayes Theorem; D006801:Humans; D016571:Neural Networks, Computer; D017286:Polysomnography; D012891:Sleep Apnea Syndromes / Q000145:classification*