Which speech changes signal problems?

One of the earliest symptoms of cognitive impairment and early Alzheimer's disease is trouble with retrieving words in conversation, according to the largest study ever done on speech analysis for this purpose.

US researchers have found that those with early-mild cognitive impairment have faster declines in measures of fluency and semantic content after adjusting for age, sex and literacy, as well as other potential confounders, including depression, sleep quality or anxiety.