As the global demographic steadily shifts toward an aging population, there is an escalating incidence of dementia and other forms of cognitive impairment. Consequently, the demand for accessible and effective measures to prevent or decelerate cognitive deterioration associated with aging is becoming increasingly pressing.
Research has consistently demonstrated a correlation between auditory impairment and the onset of dementia in the elderly. There is also growing evidence that intervention with hearing aids for those with hearing loss might decelerate the progression of cognitive challenges. Despite these insights, the correlation between hearing loss intervention and cognitive enhancement had not been thoroughly examined in a large-scale, randomized trial.
In an effort to bridge this research gap, an NIH-funded study spearheaded by Dr. Frank Lin at Johns Hopkins University embarked on a clinical trial involving close to a thousand participants aged between 70 and 84. This study assessed the cognitive decline trajectory over three years, comparing individuals who received hearing aids with those who did not.
The researchers enrolled individuals with significant hearing loss from two distinct cohorts for their study. The first group consisted of approximately 250 older adults in good health, who were part of a long-standing investigation into cardiovascular well-being across four US locations. A second group of 739 individuals was freshly gathered from local communities at the same locations. Those hailing from the heart-health research exhibited a higher propensity for dementia development, marked by advanced age and accelerated cognitive deterioration compared to their counterparts from the broader population.
The participants were then randomly assigned to one of two experimental groups. Roughly half were provided with hearing aids and trained on their usage, while the remaining participants engaged in a health education program centered on fostering healthy aging principles. Follow-up sessions at six-month intervals were conducted for both groups to fortify the training received.
Commencing at the study’s outset and continuing yearly for three years, all subjects underwent a comprehensive series of cognitive function assessments. The findings of this research were released on July 17, 2023, in The Lancet journal.
Those who were equipped with hearing aids noted a marked enhancement in their communicative abilities throughout the study’s duration. Conversely, participants in the health education cohort, as foreseen, did not report any advancements in hearing or communicative capacities.
In a comprehensive analysis involving all participants of the study, the investigators detected no significant variance in the trajectory of cognitive function between those outfitted with hearing aids and those who were not.
Yet, a more nuanced examination targeting the subset from the heart-health study—identified as having a greater susceptibility to dementia—revealed a considerable advantage linked with the use of hearing aids. In this demographic, individuals who used hearing aids witnessed a remarkable slow down in cognitive decline by nearly 50%, in contrast to their counterparts in the health-education group.
“Hearing impairment is readily treatable in the later stages of life, positioning it as a pivotal target for public health initiatives aimed at mitigating the risk of cognitive deterioration and the onset of dementia,” expresses Lin.
The investigative team is committed to an ongoing observation of the study’s participants to monitor the progressive shifts in cognitive functions. They’re concurrently examining brain imaging and data pertaining to social involvement to gain a deeper insight into how safeguarding auditory function may thwart cognitive decline among the more at-risk senior population.