a pattern of speech called tangentiality

Trump keeps losing his train of thought. Cognitive experts have
theories about why
...
...
This shifting from topic to topic, with few connections -- a pattern
of speech called tangentiality -- is one of several disjointed and
occasionally incoherent verbal habits that seem to have increased in
Trump's speech in recent years, according to interviews with experts
in memory, psychology, and linguistics.

Back in 2017, Trump's first year in the White House, a STAT analysis
showed Trump's speaking style had deteriorated since the 1980s. Seven
years on, now that Trump has the GOP presidential nomination, STAT has
repeated the analysis. The experts noted a further reduction in
Trump's linguistic complexity and, while none said they could give a
diagnosis without an examination, some said certain shifts in his
speaking style are potential indications of cognitive decline.
...
...
These could be attributed to a variety of possible causes, they said,
some benign and others more worrisome. They include mood changes, a
desire to appeal to certain audiences, natural aging, or the
beginnings of a cognitive condition like Alzheimer's disease.

https://www.statnews.com/2024/08/07/trump-mental-health-linguistic-analysis-suggests-potential-cognitive-decline-experts-say/