Speech-in-Noise Difficulty May Signal Early Brain Changes Linked to Cognitive Decline: JAMA

In the current research, researchers chose a highly characterized community-dwelling sample of elderly people from Australia. Specifically, the current study included participants recruited in the context of the large prospective study, the Aspirin in Reducing Events in the Elderly trial. Participants who had completely intact general cognitive performance and were free from dementia at the beginning of the study were followed up for a period of three years. In the process of recruitment, all participants had to undergo a series of audiological evaluations including the measurement of pure-tone thresholds and binaural speech-in-noise testing to test their central auditory function.

Finally, depending on objective data collected as well as self-reports of participants, the recruited sample of patients was divided into three subgroups according to the nature of their hearing problems: those with normal baseline hearing function, participants with non-auditory or untreated hearing loss, and finally those who were currently wearing hearing aids. Structural alterations of brain regions known to be prone to damage in Alzheimer's patients were measured through MRI of the high spatial resolution.

Key findings:

• The longitudinal study with neuroimaging successfully followed up 312 older adults living in the community who showed no signs of any dementia disorders in their initial baseline status.
• The average age for the study group was consistently reported at 73.5 years (standard deviation of 3.3 years), and the participants featured a marginal female majority (167 people; 54%).
• Decreased initial speech-in-noise ability was statistically correlated with the increased longitudinal thinning rate in the inferior parietal cortex area (β = -0.002; 95% Confidence Interval [CI], -0.003 to 0.001).
• Reduced central auditory perception resulted in accelerated structural thinning of the precuneus (β = -0.001; 95% CI, -0.002 to 0.000).
• Speech decoding speed was correlated with faster cell loss in the middle temporal cortex area (β=−0.001; 95% CI, −0.002 to −0.001).
• A direct correlation was found between poor central hearing and thinning of the superior temporal sulcus region (β = -0.001; 95% CI, -0.002 to 0.000).

In summary, in this cohort study involving cognitively healthy older patients, central auditory processing dysfunction, and not peripheral hearing impairment or wearing hearing aids, predicted faster thinning of the cortical areas involved in speech processing. The performance of speech in noise might be considered a potential early behavior marker of brain vulnerability occurring before any cognitive impairment. This study provides definitive evidence which serves as a practical basis for modern neurology. It proves beyond reasonable doubt that failure to understand speech in noise indicates stress of brain networks, not ears only.

Reference:

Zanin J, McNeil JJ, Rance G. Speech-in-Noise Ability and Longitudinal Cortical Thinning in Speech-Processing Networks. JAMA Otolaryngol Head Neck Surg. Published online May 28, 2026. doi:10.1001/jamaoto.2026.1050