Figure 4.

(A) Sunburst chart describing the proportion of feature extraction toolkits used and neurological disorders. ‘Custom' describes studies which did not mention the toolkit used or which utilised custom methods to extract features. (B) Sunburst chart describing the proportion of predictive modeling approaches used and neurological disorders. Categorical classification: SVM, support vector machines; k-NN, k-nearest neighbors algorithm; DT, decision trees; RF, random forests; GMM, Gaussian Mixture Models; HMM, Hidden Markov Models; Regression models: LR, linear regression; regression: other regression methods. ANNs, Artificial neural networks; CNN, convolutional neural networks; LSTM, long short-term memory networks; PD, Parkinson's disease; AD, Alzheimer's disease; ALS, amyotrophic lateral sclerosis.