Machine learning, waveform preprocessing and feature extraction methods for classification of acoustic startle waveforms

The acoustic startle response (ASR) is an involuntary muscle reflex that occurs in response to a transient loud sound and is a highly-utilized method of assessing hearing status in animal models. Currently, a high level of variability exists in the recording and interpretation of ASRs due to the lack of standardization for collecting and analyzing these measures. An ensembled machine learning model was trained to predict whether an ASR waveform is a startle or non-startle using highly-predictive features extracted from normalized ASR waveforms collected from young adult CBA/CaJ mice. Features were extracted from the normalized waveform as well as the power spectral density estimates and continuous wavelet transforms of the normalized waveform. Machine learning models utilizing methods from different families of algorithms were individually trained and then ensembled together, resulting in an extremely robust model. ASR waveforms were normalized using the mean and standard deviation computed before the startle elicitor was presented 9 machine learning algorithms from 4 different families of algorithms were individually trained using features extracted from the normalized ASR waveforms Trained machine learning models were ensembled to produce an extremely robust classifier (C) 2020 The Authors. Published by Elsevier B.V.