The way the brain processes speech could serve as a predictor of early dementia

March 15, 2017
Credit: CC0 Public Domain

Early dementia is typically associated with memory and thinking problems; but older adults should also be vigilant about hearing and communication problems, suggest recent findings in a joint Baycrest-University of Memphis study.

Within who scored below the normal benchmark on a screening test, but have no noticeable communication problems, scientists have discovered a new potential predictor of through abnormal functionality in regions of the brain that process speech (the brainstem and auditory cortex).

These are thought to be more resilient to Alzheimer's. However, this discovery demonstrates changes occur early in the brain's conversion of into understandable words. This finding could be the first sign of decline in brain function related to communication that presents itself before individuals become aware of these problems.

Their research technique of measuring using an electroencephalogram (EEG) in these brain regions also predicted (MCI), a condition that is likely to develop into Alzheimer's, with 80 per cent accuracy. This test could be developed into a cost-effective and objective diagnostic assessment for older adults.

The study, published online in the Journal of Neuroscience prior to print publication, looked at older adults with no known history of neurological or psychiatric illnesses with similar hearing acuity.

The brain activity within the brainstem of these older adults demonstrated abnormally large speech sound processing within seven to 10 milliseconds of the signal hitting the ear, which could be a sign of greater in the future.

"This opens a new door in identifying biological markers for dementia since we might consider using the brain's processing of speech sounds as a new way to detect the disease earlier," says Dr. Claude Alain, the study's senior author and senior scientist at Baycrest's Rotman Research Institute (RRI) and professor at the University of Toronto's psychology department.

"Losing the ability to communicate is devastating and this finding could lead to the development of targeted treatments or interventions to maintain this capability and slow progression of the disease."

The study involved 23 older adults between the ages of 52 and 86. Participants were separated into two groups based on their results on a dementia screening test, the Montreal Cognitive Assessment (MoCA). Researchers measured brain activity in the brainstem while participants were watching a video. They measured brain activity in the while participants were identifying vowel sounds. Statistical methods were used to combine both sets of brain activity to predict MCI.

"When we hear a sound, the normal aging brain keeps the sound in check during processing, but those with MCI have lost this inhibition and it was as if the flood gates were open since their neural response to the same sounds were over-exaggerated," says Dr. Gavin Bidelman, first author on the study, a former RRI post-doctoral fellow and assistant professor at the University of Memphis. "This functional biomarker could help identify people who should be monitored more closely for their risk of developing dementia."

The next steps involve studying whether those individuals who already have dementia or convert early from MCI to dementia also demonstrate these same changes in when they hear speech.

Research for this study was conducted with support from the Grammy Foundation, the Canadian Institutes of Health Research, the FedEx Institute of Technology and the Center for Technologies and Research in Alzheimer's Care, which supported the staff and equipment needed to conduct the study.

With additional funds, researchers could explore developing a portable, reliable and easy-to-use alternate diagnostic test for MCI that incorporates the body's different senses.

"MCI is known to cause changes in different senses, such as vision or touch," says Dr. Alain. "If we could incorporate these changes into a wireless EEG test, we could combine all this information and develop a better biomarker. One day, doctors could administer a short, 10-minute assessment and instantly provide results."

"This could offer a new diagnostic assessment that tests a person's cognitive abilities, such as their ability to communicate, and objectively measure physiological changes in the brain that reflect early signs of dementia," says Dr. Bidelman.

Explore further: Study finds prolonged sleep may predict dementia risk

Related Stories

Study finds prolonged sleep may predict dementia risk

February 22, 2017
Data from the Framingham Heart Study has shown that people who consistently sleep more than nine hours each night had double the risk of developing dementia in 10 years as compared to participants who slept for 9 hours or ...

Exercise results in larger brain size and lowered dementia risk

August 2, 2016
Using the landmark Framingham Heart Study to assess how physical activity affects the size of the brain and one's risk for developing dementia, UCLA researchers found an association between low physical activity and a higher ...

Researchers identify part of the brain that compensates for hearing loss in older adults

August 4, 2016
Researchers have pinpointed the specific part of the brain that older adults rely on to differentiate speech sounds in background noise, which could revolutionize the treatment of hearing loss.

More evidence that musical training protects the brain

February 2, 2015
Scientists have found some of the strongest evidence yet that musical training in younger years can prevent the decay in speech listening skills in later life.

Ability to process speech declines with age

October 5, 2016
Researchers have found clues to the causes of age-related hearing loss. The ability to track and understand speech in both quiet and noisy environments deteriorates due in part to speech processing declines in both the midbrain ...

Study confirms 'sniff test' may be useful in diagnosing early Alzheimer's disease

December 20, 2016
Tests that measure the sense of smell may soon become common in neurologists' offices. Scientists have been finding increasing evidence that the sense of smell declines sharply in the early stages of Alzheimer's, and now ...

Recommended for you

Lifestyle changes to stave off Alzheimer's? Hints, no proof

July 20, 2017
There are no proven ways to stave off Alzheimer's, but a new report raises the prospect that avoiding nine key risks starting in childhood just might delay or even prevent about a third of dementia cases around the world.

Steering an enzyme's 'scissors' shows potential for stopping Alzheimer's disease

July 19, 2017
The old real estate adage about "location, location, location" might also apply to the biochemical genesis of Alzheimer's disease, according to new research from the University of British Columbia.

Brain scans may change care for some people with memory loss

July 19, 2017
Does it really take an expensive brain scan to diagnose Alzheimer's? Not everybody needs one but new research suggests that for a surprising number of patients whose memory problems are hard to pin down, PET scans may lead ...

Can poor sleep boost odds for Alzheimer's?

July 18, 2017
(HealthDay)— Breathing problems during sleep may signal an increased risk for Alzheimer's disease, a trio of studies suggests.

Hearing is believing: Speech may be a clue to mental decline

July 17, 2017
Your speech may, um, help reveal if you're uh ... developing thinking problems. More pauses, filler words and other verbal changes might be an early sign of mental decline, which can lead to Alzheimer's disease, a study suggests.

Bacteria found in Alzheimer's brains

July 17, 2017
Researchers in the UK have used DNA sequencing to examine bacteria in post-mortem brains from patients with Alzheimer's disease. Their findings suggest increased bacterial populations and different proportions of specific ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.