麻豆传媒

LONDON -- Changes in speech may be an early warning sign for cognitive impairment, researchers reported here.

In an analysis of data from the WRAP sample, participants with early mild cognitive impairment (MCI) declined faster in measures of fluency and semantics than those with normal cognition, Kimberly Mueller, PhD, of the University of Wisconsin, and colleagues reported during a press briefing at the .

Greater changes in fluency also predicted which cognitively normal patients would progress to early MCI, Mueller said.

"Associations between very early speech changes and early cognitive decline are important, because providing a speech sample is a relatively quick, easy, and inexpensive activity," Mueller said during the briefing. "Cognitive changes may show up in connected speech."

One of the earliest symptoms of cognitive impairment and early Alzheimer's disease is trouble with retrieving words in conversation. Studies have shown that speech changes can signal cognitive problems, but most of these have been retrospective with small sample sizes, Mueller said.

So she and colleagues studied 264 patients in the Wisconsin Registry for Alzheimer's Prevention (WRAP) study who had at least two assessments of connected speech -- which is, essentially, "a measure of everyday talking in a relatively controlled [setting]," Mueller said. In a nutshell, participants look at a picture and describe what they see.

The researchers then feed the transcripts into a language analysis program that assesses these key areas: lexical (diversity of vocabulary); semantic content (the number of "content" words such as nouns and verbs versus non-content words like pronouns); syntax; and fluency.

Of the 264 participants, 200 were cognitively healthy, while 64 had early MCI. Those with early MCI were slightly older and more were male, but otherwise the groups had similar levels of education and literacy as well as similar family history of Alzheimer's.

Overall, Mueller and colleagues found that those with early MCI had faster declines in measures of fluency and semantic content after adjustment for age, sex, and literacy (P=0.03 for both), and those results remained the same after further adjustment for other potential confounders including depression, sleep quality, or a diagnosis of anxiety.

A larger negative change in fluency also predicted who would go on to be classified with early MCI at their second speech visit, they found (P=0.004).

On specific measures of language ability, Mueller and colleagues found that those with early MCI produced shorter sentences and took longer to express the same ideas as the cognitively healthy group at both time points, as measured by mean length of utterance (15.7 versus 11.6, P<0.001 at time point 1; 17.7 versus 13.0, P=0.001 at time point 2).

They also had lower scores on words per minute (143.3 versus 132.8, P=0.02) and semantic units per minute (20.6 versus 18.3, P=0.03) at the second time point.

"To be able to extract all of these measures in just one minute is a quick and low-burden activity that could be an important addition to a cognitive battery," Mueller said, adding that an understanding of "when and how speech changes in the continuum of cognitive decline can lead to development of cognitive interventions to keep people functioning for longer periods."

David Knopman, MD, of the Mayo Clinic, who moderated the briefing at which the findings were presented, said speech assessment may be useful for the early diagnosis of cognitive impairment.

"Speech gets at the idea that with dementia -- though we commonly think of it in our fairly reductionist way as being associated with memory loss -- there are other cognitive deficits, and something like an automated speech analysis may provide some clues in an inexpensive and non-confrontational manner," he said.

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