The Impact of Depression and Apathy on Sensory Language

The debate that language strongly influences thought is equally met by those who suggest language does not influence thought. While historically, the ability to communicate with words was believed to be intimately tied to an ability to form thoughts, we would argue that thought and language are linked together through our sensory and motor systems and severely impacted by depression and apathy. We test this by conducting parts of speech analysis from the comparative longitudinal studies of two highly creative and prolific writers, where one is diagnosed with Alzheimers disease (AD), and the other lives a long and healthy life. We calculate function and contents word ratios, measure lexical repetition, and the use of sensory-based words in textual language to test for depression and apathy in AD which is supported by Mann-Whitney U-Testing and Principal Component Analysis. Our results support the hypothesis that thought and language are impacted by depression and apathy and revealed in a persons writing style 12 years before a formal diagnosis of Alzheimers disease presents. We find higher lexical repetition in language 12 years prior to one author being diagnosed with AD while not apparent in the other. We identify low olfactory word use and also find that an increased use of sensory-based adjectives might be a sign of the early onset of Alzheimers disease.