Hearing intervention shows promise in protecting older adults at increased risk for cognitive decline

While the results were negative in the total study population, the hearing intervention slowed cognitive decline in older adults with mild to moderate hearing loss by 48% in a pre-specified segment of the study population consisting of the 238 people participating in an ongoing observational study of heart health. The findings from the ACHIEVE study were simultaneously published in The Lancet.

The ACHIEVE study is a randomized trial of older adults aged 70-84 with untreated hearing loss who were free from substantial cognitive impairment, conducted at four U.S. sites. 977 total participants were recruited from two study populations:and 739 healthy community volunteers newly recruited to the study.

According to the researchers, at the start of the trial, all study participants generally had mild to moderate hearing loss very typical of older adults, but no substantial cognitive impairment.

The three-year intervention included use of hearing aids, a hearing "toolkit" to assist with self-management, and ongoing instruction and counseling with an audiologist. The comparison group health education control group had talk sessions with a health educator about chronic disease prevention. The total study population was analyzed, hearing intervention versus health education control; the ARIC and community subgroups were also analyzed in this manner. The primary endpoint was three-year change in a comprehensive neurocognitive testing battery, which included procedures to help ensure that hearing loss would not affect the results.

The results of the comparison of hearing intervention versus control in the total study population were negative, as was the community population comparison of hearing intervention versus control. The most interesting result was the comparison of the ARIC subgroup hearing intervention versus control, in which a 48% slowing of cognitive decline was observed.

The researchers noted that the participants from the ARIC study had more risk factors for cognitive decline, lower baseline cognitive scores, and a faster rate of three-year cognitive decline during the study than the others.

The positive results with the hearing intervention in the ARIC subgroup analysis are encouraging and warrant further investigation. Previous research has identified hearing loss as potentially the single largest dementia risk factor that can be addressed or modified with existing tools that remain underutilized."

Maria C. Carrillo, Ph.D., Alzheimer's Association chief science officer

The ACHIEVE researchers cite hearing loss as present in 65% of adults over age 60. Identifying dementia prevention strategies that can be implemented globally is an urgent priority.

"The hearing intervention had a significant effect on reducing cognitive change within three years in the population of older adults in the study who are at increased risk for cognitive decline," said Frank Lin, M.D., Ph.D., of Johns Hopkins University School of Medicine and Bloomberg School of Public Health, and co-primary investigator of the ACHIEVE study. "Hearing loss is very treatable in later life, which makes it an important public health target to reduce risk of cognitive decline and dementia, along with other dementia risk factors such as less education in early life, high blood pressure, social isolation and physical inactivity."

"The encouraging subgroup results are consistent with our understanding that strategies to reduce cognitive decline and dementia risk will likely need to affect more than one pathway to be successful. The Alzheimer's Association's ongoing U.S. POINTER Study is taking that approach through targeting multiple risk factors at the same time in a diverse, representative study population," Carrillo said.

Findings from the ACHIEVE study suggest that older adults at increased risk for cognitive decline and dementia who also have hearing loss may benefit the most from this hearing intervention within three years. According to the ACHIEVE researchers, the hearing intervention may slow down decline in thinking and memory by making listening easier for the brain, or by helping people remain more socially and physically active.

"In both the ARIC group and the new group of community volunteers, we also found that the hearing intervention improved communication abilities, social functioning and loneliness," Lin said. "Until we know more, we recommend for general health and well-being that older adults have their hearing checked regularly and any hearing issues properly addressed."

More research is needed to investigate how the hearing aids and counseling provided the cognitive benefit, and to understand the longer-term benefits of the hearing intervention.