Using Verb Fluency, Natural Language Processing, and Machine Learning to Detect Alzheimer’s Disease

Alzheimer's disease (AD) causes significant impairments in memory and other cognitive domains. As there is no cure to the disease yet, early detection and delay of disease progression are critical for management of AD. Verbal fluency is one of the most common and sensitive neuropsychological methods used for detection and evaluation of the cognitive declines in AD, in which a subject is required to name as many items as possible in 30 or 60 seconds that belong to a certain category. In this study, we develop an approach to detect AD using a verb fluency (VF) task, a specific subset of verbal fluency analyzing the subjects' listing of verbs in a given time period. We use machine learning techniques including random forest (RF), neural network (NN), recurrent NN (RNN), and natural language processing (NLP) to detect the risk of AD. The results show that the developed models can stratify subjects into the corresponding AD and control groups with up to 76% accuracy using RF, but at a cost of having to preprocess the data. This accuracy is slightly lower, but not significantly, at 67% using RNN and NLP, which involves almost no manual preprocessing of the data. This study opens up a powerful approach of using simple VF tasks for early detection of AD.