An imaging study recently highlighted changes in the metabolic functioning of the brain in people with mild cognitive impairment: some wearing hearing aids, others not.
The link between cognitive decline and hearing loss, but also that between the correction of hearing loss and the prevention of dementia, have been the subject of significant publications in recent years. However, the underlying mechanisms are not elucidated, nor are the metabolic changes that take place in the brain.
Research conducted by Natalie Quilala, under the mentorship of Daniel Silverman, head of the nuclear imaging section (within the translational imaging division) at the University of California (UCLA, Los Angeles), consisted of comparing brain images of subjects with mild cognitive impairment and diagnosed hearing loss, corrected or not, over time. Imaging, 1 year apart, showed metabolic decline in certain cortical regions. The group of hearing impaired people without hearing aids experienced a decline 1.5 times faster than that of people with hearing aids. After 2 years, the non-equipped panel presented a significant difference with the control group (without diagnosed hearing loss), while the hearing aid users did not present any excess metabolic decline.
The study authors tentatively conclude that hearing loss accelerates the progression of cognitive impairment in people who suffer from it, but that the use of hearing aids can slow this progression.
A- Frontal cortex regions with subnormal metabolism (less than 5th percentile, shown in color) at baseline, in subjects with mild cognitive impairment and untreated hearing loss. B- Frontal cortical regions with metabolism below normal two years later. Red colors correspond to a more severely decreased metabolism. The group of subjects using hearing aids did not experience significant decline in any frontal cortical region during the same period.
Visual credit: Natalie Quilala, Stephen Liu, Helen Struble, Daniel Silverman, University of California, Los Angeles, Los Angeles, California.
