Artificial intelligence techniques for classification of Alzheimer's disease using neuroimaging data: a review

Alzheimer's disease (AD) is a gradually advancing brain disorder marked by memory impairment. The incurable, progressive nature of the disease leads to the dementia stage. Treatment is effective in the early stage, and it can be controlled but not cured. Artificial Intelligence ( AI) learning models are used in medical science to detect and classify diseases into specific categories. Features are extracted from medical images and trained using AI learning models to perform an accurate diagnosis of AD. Recent advancements in machine learning (ML) and deep learning (DL) models have demonstrated significant potential in identifying AD across various data modalities, including neuroimaging, genetic information, and clinical assessments. This study focuses on the application of advanced ML and DL techniques in the identification and classification of AD, including regression models, decision trees, random forests, support vector machines (SVMs), k-nearest neighbors (KNNs), ensemble models, convolutional neural networks (CNNs), recurrent neural networks (RNNs), and generative adversarial networks (GANs). Each model is analyzed for its strengths, limitations, and performance metrics, with particular emphasis on the importance of data preprocessing and augmentation techniques to improve model accuracy and robustness. The review highlights that multimodal approaches, particularly the fusion of MRI and PET data, enhance classification accuracy compared to single-modality models. Additionally, transfer learning techniques have shown promise in overcoming data limitations by leveraging pretrained models. The review also highlights the critical role of evaluation metrics in assessing model performance, emphasizing the need for a diverse set that includes accuracy, precision, recall, F1-score, and Cohen's Kappa. The study identifies gaps in the current literature, including underreporting of certain metrics and the need for more comprehensive evaluations, and provides recommendations for future research. Finally, this study discusses the challenges and opportunities in the field, including improving model generalizability, enhancing interpretability, advanced data preprocessing and augmentation, integration with clinical workflows, and multimodal data fusion. This review provides consolidated information that may be useful for researchers, clinicians, and data scientists, offering insights into current trends, challenges, and future research directions in AI-driven AD detection.