An fNIRS Investigation of the Prefrontal Cortical Processing Demands Associated with a Communication Based Assessment for Mild Cognitive Impairment

When working with people who have communication impairments, there are few cognitive assessment tools to discern between baseline function, mild cognitive impairment (MCI), and Alzheimer’s Disease (AD). While there are some available behavioral measures, this repertoire needs to be expanded. Because these diseases are progressive, these tasks must hold up against test/re-test principles, including accurate tracking over time. This study proposes to expand these tools used to assess MCI, exploring tasks linguistically and with functional near-infrared spectroscopy (fNIRS) to monitor neural activation during naturalistic communication, or discourse. This study observed fifteen total participants, all from the University of Vermont, as they talked through nine various discourse tasks. These tasks included three complex procedural, two simple procedural, two baseline rest tasks, and two additional tests. The baseline rest tasks and additional tests were not analyzed. The hypotheses were that the complex procedural tasks would elicit higher activation than the simple tasks and that the novel tasks would be equivalent to the previously-established tasks. The results show general increased PFC activation over all discourse tasks, indicating involvement of the PFC in connected discourse communication. Results also show increased prefrontal cortex (PFC) activation while performing complex procedural discourse tasks compared to simple procedural discourse tasks. The novel complex procedural discourse tasks were found to be linguistically and cognitively equivalent to the established measure. The novel simple discourse task was also found to be equivalent to its previously-established counterpart. These tasks may have implications in clinical assessment tools in the future. More research must be conducted investigating other brain regions to gain a better insight into the functional brain mechanisms of mild cognitive impairment and Alzheimer’s Disease to determine more useful assessment tools