Dementia and the Presidency

 There has been a lot of speculation about the mental competency of the two current Presidential candidates. The discussion has been muddied by deliberate distortions to the point where nothing of value can be extracted. It turns out, however, that progression toward Alzheimer's Disease can be measured and analyzed through rigorous statistical methodology based on an examination of verbal performance in press conferences.

Such an analysis, performed in 2019, compared the records of Ronald Reagan and George H.W. Bush. Bush remained free of dementia throughout his presidency.  Reagan revealed his Alzheimer's diagnosis only six years after he left office. The study was entitled, Tracking Discourse Complexity Preceding Alzheimer’s Disease Diagnosis: A Case Study Comparing the Press Conferences of Presidents Ronald Reagan and George Herbert Walker Bush. The authors were Visar Berisha,* Shuai Wang, Amy LaCross, and Julie Liss.

The abstract describes the study's methodology:

Changes in some lexical features of language have been associated with the onset and progression of Alzheimer’s disease. Here we describe a method to extract key features from discourse transcripts, which we evaluated on non-scripted news conferences from President Ronald Reagan, who was diagnosed with Alzheimer’s disease in 1994, and President George Herbert Walker Bush, who has no known diagnosis of Alzheimer’s disease. Key word counts previously associated with cognitive decline in Alzheimer’s disease were extracted and regression analyses were conducted. President Reagan showed a significant reduction in the number of unique words over time and a significant increase in conversational fillers and non-specific nouns over time. There was no significant trend in these features for President Bush.
Keywords: Early diagnosis, language, medical informatics, natural language processing

The Discussion:

President Reagan was not diagnosed with AD until August of 1994, but the results of our analyses suggest that changes in speaking patterns were becoming detectable years prior to clinical diagnosis. Analysis of his transcripts revealed significant differences in variables known to be associated with the onset of dementia. We found that the use of unique words in the discourse of RR declined over time, and the use of non-specific nouns and fillers increased over time. To address the potential confound associated with changes resulting from healthy aging, we compare RR’s transcripts to those of GHWB. At the start of their presidencies, RR was 69 years old, and GHWB was 64 (the years 1981 and 1989 respectively). Although the two age spans differ slightly, GHWB provides the most comparable case among modern American presidents. Furthermore, when we analyze the press conferences from GHWB’s last two years in office (starting at age 66), there is still no statistically significant change in these linguistic variables...

Records similar to that of their predecessors are available for Biden and Trump, so there appears to be no good reason why an analysis of their lexical performances could not be conducted.  Perhaps such an effort has been undertaken, but it would be a little surprising to see such a thing come to light at this point.  Either political party, if in possession of such a study of the opposition, would likely be reluctant to publicize it for fear that it would stimulate a demand for a counter-study.  Any independent study, however objective, would come under attack as promoting a biased, politically motivated attack.  

Perhaps, in five years, we will have a chance to see a fact-based account of the issue.