#7
The Gamma-Sweep ASSR: Measuring Hearing-Related Changes in the Brain
Melina Markotjohn1, Steven Aiken2
1Faculty of Medicine, Dalhousie University, Halifax. 2School of Communication Sciences and Disorders, Dalhousie University, Halifax.
This research explores the link between hearing loss and cognitive decline, aiming to develop a diagnostic tool to track brain changes associated with both. Using the Gamma-Sweep Auditory Steady-State Response (ASSR), the study focuses on detecting auditory-driven brain changes in areas like the hippocampus and temporal lobes, which are tied to cognitive decline. Specifically, hearing loss is known to reduce cortical volume and inhibit cortical processing, affecting speech comprehension and temporal processing.
The research’s first objective is to evaluate the accuracy and reliability of Gamma-Sweep ASSRs by measuring brain responses to amplitude-modulated white noise in normal-hearing adults, capturing precise cortical and brainstem activity. This will help determine whether sweeping measures can better reflect brain responses compared to non-sweeping ones.
The second objective focuses on older adults with mild to moderate hearing loss, examining correlations between ASSR measurements and cognitive performance. This includes assessments of speech-in-noise thresholds, memory tasks, and cognitive speed. Anticipated outcomes include better early detection of cognitive decline linked to hearing loss, which could lead to timely interventions.
This research is significant for its potential to expand knowledge on how auditory degradation impacts cognitive function, offering new avenues for non-invasive detection methods. Policy implications suggest routine hearing evaluations as part of dementia risk management, reinforcing the need for early intervention strategies in both clinical and public health contexts.
#76
Saltiness perception and aging: a perspective from purée sensory testing
María Victoria Estrella1, Priya Kathirvel1, Linda Mann1, Alex Martynenko2, Bohdan Luhovvy1
1Department of Applied Human Nutrition, Mount Saint Vincent University, Halifax. 2Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro.
Sodium intake in older adults in Canada exceeds the recommended level (Flexner et al., 2023). Health Canada set the Chronic Disease Risk Reduction Intake (CDRR) for sodium at 2,300mg. Reducing sodium intake above the CDRR is an important dietary strategy in the prevention of hypertension and its comorbidities. Adding salt to food products results in their desirable saltiness intensity (SI) and improved palatability. Testing sodium chloride solutions indicates a lower SI perception in older adults than younger adults (Sato et al., 2022). A lower SI perception in older adults may result in increased sodium intake or lower food intake due to food’s diminished palatability. The objective was to assess the SI perception in adults (19-65y) and older adults (66y and older) using newly formulated pulse-based purées that meet requirements for meal replacements and for the food intended for dysphagia. Methods: SI was evaluated using 100mm visual analogue scales (VAS). The SI mean values derived from five food samples were compared between adults (n=35, 38.3±11.5y) and older adults (n=30, 73.3±6.4y) using an unpaired t-test. Results: Five puréed meal replacements were formulated, and their sodium content was 280-440mg (12-19% daily value) per 250g. The SI perception was lower in older males by 12mm-VAS compared to adult males (P=0.02), while the difference in females was not significant. Conclusion: food product development for older adults needs to account for diminished SI perception in older males and, in addition to added moderate amounts of salt, use natural low-sodium ingredients that enhance the perception of saltiness.