A new study by a team of researchers from MIT, Cornell University, and Massachusetts General Hospital has shed light on a subtle yet significant change in cognitive function that could serve as an early warning sign of dementia, particularly Alzheimer's disease. Challenging the common perception that memory loss is the earliest indicator of decline, the study suggests language-processing difficulties, specifically in handling complex grammatical structures, could sound the alarm sooner.
The research focused on individuals with amnestic mild cognitive impairment (aMCI), a condition linked to heightened risk of developing Alzheimer's, and discovered that while these individuals were competent with basic sentence structure, they struggled with the interpretation of ambiguous sentences. This language-processing deficit exists aside from their memory issues, pointing to a separate cognitive pathway possibly affected early in the disease process. In a statement obtained by MIT News, Suzanne Flynn, an MIT linguistics scholar and co-author of the study, elaborated on the significance of their findings in understanding linguistic abilities in the context of aMCI.
Moreover, the study, published in the Journal of Neurolinguistics, differentiates itself from previous research by moving beyond single words to analyze more complex linguistic structures. "We found a breakdown at that higher level where you're integrating form and meaning," Barbara Lust, a professor emerita at Cornell University and a co-author of the study, told MIT News. Researchers compared the performance of 61 aMCI patients from Massachusetts General Hospital with cognitively healthy individuals in control groups, focusing on sentence constructions involving "anaphora"—a linguistic term that refers to the relation between a pronoun and its antecedent in a sentence.
Striking differences became apparent when participants were asked to process sentences with pronouns that were ambiguous, requiring the interpreter to decide whether an additional noun is being referenced. As observed in the experiments, aMCI patients consistently underperformed compared to the control groups when tasked with sentences featuring "anaphoric coreference." Janet Cohen Sherman, an associate professor of psychology at Massachusetts General Hospital, noted in an interview with MIT News, "When they didn’t have to go outside the sentence for context, sentence production was preserved in the individuals with aMCI whom we studied."
This line of research offers a potential redirection for neuroscience in the fight against Alzheimer's and other forms of dementia by suggesting new cognitive biomarkers for early detection. According to the researchers, language could be a predictor of neurological decline, leading to the development of more targeted treatments. "The more precise we can become about the neuronal locus of deterioration, the bigger difference it will make in terms of developing treatment," Flynn asserted on MTI News, projecting optimism about the study's implications. The research was backed by multiple sources, including the Cornell University Podell Award and funding from various institutes at Cornell, Apple Corporation, and Massachusetts General Hospital.
