Do Hearing Aids Slow Dementia in MCI? Results Are Mixed

Hearing aid use was not associated with a reduced rate of transition from mild cognitive impairment (MCI), thus missing a new study’s primary outcome, although key secondary outcomes did show improvements in cognition.In an open-label randomized clinical trial (RCT) of more than 700 older adults with MCI, there was no significant difference in the conversion rate to dementia between those who received a hearing aid intervention and those who received hearing care education.However, the conversion rate to dementia was lower than anticipated, making the trial underpowered to detect a difference in dementia incidence, noted Hao Wu, MD, PhD, co-investigator, Shanghai Ninth People’s Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai, China.“That is a verdict of ‘not proven’ and not ‘no benefit,’” Wu told Medscape Medical News. Here, absence of evidence is not evidence of absence.The more interesting finding, he said, was the secondary outcome of cognitive improvement, with 15.3% vs 2.4% of the hearing aid group vs the control group reverting to a Clinical Dementia Rating (CDR) global score of 0.“It cannot be read as definitive, but the difference between groups was large and internally consistent,” Wu said.The findings were published online recently in JAMA Neurology.The Search for Stronger EvidenceHearing loss is the leading modifiable risk factor for dementia, Wu noted. However, ACHIEVE, the first large RCT to assess these outcomes, was conducted in cognitively healthy older adults and found no significant effect on cognitive change at 3 years. Still, there was a 48% cognitive decline reduction in those with more risk factors in prespecified analyses.Additionally, while several observational studies have shown beneficial results, they were often limited by various factors, including residual confounding.The current investigators sought to assess whether a hearing intervention would prevent patients with MCI from converting to dementia.“We wanted to provide evidence strong enough to guide a recommendation,” Wu said.Their multicenter, parallel-group, open-label, randomized controlled trial was conducted from September 2021 to February 2024, with follow-up completed in February 2026.All participants (mean age, 74.53 years; 64.4% men) were from Shanghai, had both MCI (CDR global score, 0.5) and moderate-to-severe hearing loss, and were randomly assigned to receive either a hearing aid intervention (n = 353) or hearing care education (control group; n = 350).Conversion from MCI to dementia-level impairment (CDR global score > 1) at 24 months was the primary outcome. Prespecified secondary outcomes included a CDR score shift from 0.5 to 0, signifying cognitive improvement, as well as CDR global and domain score changes.Low Conversion RateResults showed a conversion rate from MCI to dementia-level impairment of 3.09% in the hearing aid group (95% CI, 1.62-5.74%) and 4.74% in the control group (95% CI, 2.60-8.29%), which was not a significant between-group difference (relative risk [RR], 0.59; P = .23).Wu noted that the conversion rate to dementia being lower than estimated for both groups wasn’t entirely unexpected. “Our participants were recruited from otology clinics and community settings, with relatively preserved daily function and regular health oversight,” he said.On the other hand, the rate of cognitive improvement was significantly greater in the hearing aid than the control group (RR, 5.94; P < .001).“Although exploratory and to be interpreted with caution, this difference at least raises the possibility that hearing intervention might support cognitive improvement in some older adults with MCI,” Wu said. “We hope further evidence will help clarify whether this potential indeed holds.”There were also significant differences between the intervention and control groups in CDR global score at 24 months (0.45 vs 0.51, respectively) and in the CDR domain score for memory (0.44 vs 0.51; P < .001 for both comparisons).There were no study-related adverse events for either treatment group, and no reports of recurrent inflammation of the external auditory canal, suppurative otitis media, or cholesteatoma.The study was funded by several sources, including the Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, the National Natural Science Foundation of China, and the Shanghai Shenkang Hospital Development Center. Additional funding sources and disclosure information for the study investigators are available in the original study publication.