One-Minute Speech Test May Flag Early Cognitive Impairment

July 19, 2017

LONDON — A simple 1-minute speech test could be an easy and effective screening tool to identify patients with early indications of mild cognitive impairment (MCI), a new study suggests.

Presented here at the Alzheimer's Association International Conference (AAIC) 2017, the study showed that subtle changes in connected speech over time, especially declines in fluency and content, were associated with very early decline in cognition.

"Problems with retrieving words in conversations are often the earliest symptom of cognitive impairment," lead author Kimberly Mueller, PhD, University of Wisconsin School of Medicine and Public Health, Madison, told Medscape Medical News. "Our study is the largest prospective, longitudinal study of spontaneous speech samples and cognitive impairment." 

"It is possible that connected speech could be a performance-based, everyday activity that could make a good screening tool in the clinic for mild cognitive impairment, as it places a low burden on both the patient and the doctor," said Dr Mueller. "Once these people have been identified, it may be possible to develop cognitive interventions to keep them functional for longer."

Commenting for Medscape Medical News, David Knopman, MD, professor of neurology at the Mayo Clinic in Rochester, Minnesota, and chair of the Alzheimer's Association Medical and Scientific Advisory Council, said, "We know speech changes — such as the loss of the ability to generate the required word — is one of the earliest manifestations of cognitive impairment, and a reduction in letter fluency, naming as many words as possible beginning with a given letter, are predictors of future dementia."

"These researchers have studied a speech sample, which only takes a minute to record, and they found this had predictive value on who developed early mild cognitive impairment," said Dr Knopman.   

"The idea is that it could be used as an easy screening tool in primary care. We know primary care doctors underdiagnose cognitive impairment as current tests require a 10-minute exam, but this was just a 1-minute speech recording with automated analysis; that would be very efficient," he added. "It is an idea that could be developed."

Analyzing WRAP

For the study, Dr Mueller and colleagues analyzed two speech samples, taken 2 years apart, from 264 participants in the Wisconsin Registry for Alzheimer's Prevention (WRAP), a study that follows individuals in their mid-50s who are cognitively normal at baseline but have a parent with Alzheimer's.

Of the participants, 64 were identified as having very early MCI based on cognitive testing over 8 to 10 years. The speech samples, which averaged 1 minute each, were collected by asking the participants to describe a simple picture.

The researchers then assessed four measures of connected speech: lexical (vocabulary, diversity, relevant ideas), semantic (use of nouns and ratio of nouns to pronouns), syntax (grammatical complexity), and fluency (pauses and repetitions). 

Results showed that participants classified as having early MCI declined faster in measures of fluency and content (P = .03 for both measures) and steeper change in fluency scores predicted early MCI status at the most recent visit (P = .004).

Dr Mueller noted that participants with early cognitive decline used shorter sentences and fewer words and ideas per minute. The content of their speech was also less specific, with a higher proportion of pronouns to nouns, and their fluency was more disrupted, with more hesitations, word repetitions, and filled pauses using "um" or "uh."

"We don't know whether the individuals with early mild cognitive impairment will go on to develop Alzheimer's, so we will continue to follow them. Our next step is to repeat these analyses with participants who have other biomarker evidence, such as amyloid plaques and neurofibrillary tangles as seen on PET [positron emission tomography] scans," she said.

"Speech analysis may be a valuable cognitive marker to add to clinical assessments of cognitive function in the future."

She added that interruption of fluency is "of course normal throughout life and shouldn't be a major cause of worry," but changes should be monitored.

"We have identified a group in our cohort with the earliest signs of cognitive decline — earlier than we would have previously thought of as mild cognitive impairment," said Dr Mueller.

People in this sample were highly educated, with an average of 16 years of education, and are performing within the range of normal cognitive testing, she noted. "But over time we can identify a decline and diagnose very early mild cognitive impairment compared with their own normal."

Hearing Loss–MCI Link

Another analysis from the WRAP cohort found a link between hearing loss and MCI.

Presenting the data, Taylor Fields, BS, also from the University of Wisconsin School of Medicine and Public Health, analyzed cognitive data from 783 study participants and asked whether they had been diagnosed with hearing loss.

Over the course of 4 years, 72 members of the group (9.2%) reported being diagnosed with hearing loss. Relative to those who reported normal hearing, the participants with hearing loss were more likely to score significantly poorer on cognitive tests and were approximately three times more likely to be characterized as having MCI.

"This study suggests that hearing loss could be an early indicator of worsening cognitive performance in older adults," Fields said. "Identifying and treating hearing loss could have value for interventions aimed at reducing the burden of Alzheimer's disease."

Both studies were funded by grants from the National Institutes of Health. The presenters have disclosed no relevant financial relationships.

Alzheimer's Association International Conference (AAIC) 2017. Abstracts 18732 and 15004. Presented July 17, 2017.

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