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Effects of Age and Extended High-Frequency Hearing Loss on Auditory Memory, Sequencing and Speech Perception in Noise in Marathi-Speaking Adults

This study demonstrates that in Marathi-speaking adults with normal conventional hearing, the combination of advancing age and extended high-frequency hearing loss significantly impairs auditory memory, sequencing, and speech perception in noise, highlighting the clinical necessity of extended high-frequency audiometry for early detection of functional auditory decline.

Original authors: Shubham Kumawat, Vivek Rucha

Published 2026-08-03

📖 6 min read🧠 Deep dive

CC BY 4.0

Original authors: Shubham Kumawat, Vivek Rucha

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

The Hidden Frequency and the Aging Ear

Imagine your ears are like a high-end radio. For decades, doctors have checked if this radio works by tuning into the standard stations—the clear, familiar voices of human speech that sit between 250 Hz and 8,000 Hz. If the radio picks up these stations loud and clear, we usually say, "Your hearing is perfect." But there's a whole world of sound happening just above that top dial, in the "extended high-frequency" range (above 8,000 Hz). Think of this as the ultra-high-definition static or the subtle, shimmering harmonics that give a sound its texture and clarity. While we can't always hear these frequencies as distinct tones, they act like the secret ingredients in a recipe; without them, a dish might still be edible, but it lacks the depth needed to taste it perfectly in a noisy kitchen.

This is where the story gets tricky. As we get older, or if we've been exposed to loud noises, these "secret ingredients" can start to spoil or disappear, even if the main radio stations still sound fine. Scientists call this "Extended High-Frequency Hearing Loss" (EHFHL). The big question researchers have been asking is: Does losing these hidden frequencies actually make it harder to understand what people are saying when there's background chatter? And does this problem get worse as we age, or is our brain's memory and processing power strong enough to fill in the gaps? This paper dives into that mystery, looking at how our brains handle the loss of these high notes and whether age makes the struggle harder.

The Study: Tuning into the Invisible

The researchers behind this study decided to investigate how two factors—age and extended high-frequency hearing loss (EHFHL)—team up to affect three specific skills in adults who speak Marathi: auditory memory (how well you can hold a list of words in your head), auditory sequencing (how well you can put those words in the right order), and speech perception in noise (how well you can understand a sentence when a crowd is talking around you).

They gathered 80 adults and split them into four groups based on two things: their age (Young: 20–39 years; Middle-aged: 40–60 years) and whether they had this "hidden" hearing loss. To find the hidden loss, they didn't just check the standard radio stations; they tested the frequencies at 8, 10, 12.5, and 16 kHz. If the average hearing at these high pitches was worse than 26 dB HL, they were marked as having EHFHL. Everyone else had "normal" hearing on a standard test.

The team then gave everyone a series of tests in Marathi. They asked them to remember lists of words, repeat them in the correct order, and identify words spoken over a background of four people talking at once.

What They Found: The Age Gap and the Hidden Noise

The results painted a fascinating picture of how our brains and ears interact as we get older.

1. The "Young and Healthy" Group
When the researchers looked at the young adults (20–39) who had normal standard hearing, they found something surprising: having that hidden high-frequency loss didn't seem to bother them at all. Whether they had the loss or not, their memory, sequencing, and ability to hear in noise were almost identical. It's as if their brains had a massive "reserve tank" of processing power. Even if the high-frequency "ingredients" were missing, their young brains were so efficient at filling in the blanks that they didn't notice the difference.

2. The "Middle-Aged" Group
The story changed dramatically for the middle-aged adults (40–60). Here, the hidden hearing loss became a major problem.

Without the loss: Even in this group, getting older made it slightly harder to remember lists of words (auditory memory), but their ability to order them and hear in noise remained fairly stable.
With the loss: This is where the trouble started. Middle-aged adults with the hidden high-frequency loss struggled significantly more than their peers without it. They had much worse memory, worse sequencing skills, and found it incredibly hard to understand speech in noise. The study found that for this group, the combination of getting older and losing those high frequencies created a "perfect storm." The effect was so strong that it made their performance drop sharply across all three tests.

3. The "Add-On" Effect
The study showed that age and hearing loss don't just add up; they multiply the problem. In the groups without the hidden loss, age only really hurt memory. But in the groups with the hidden loss, age hurt memory, sequencing, and the ability to hear in noise. It's like driving a car: a young driver can handle a flat tire (hearing loss) easily, but an older driver with the same flat tire might struggle to keep the car on the road.

4. The Predictors
When the researchers used math to figure out what was driving these changes, they found a clear pattern:

Age was the biggest boss when it came to memory and sequencing. As people got older, these skills naturally declined.
The hearing loss (EHFPTA) was the biggest boss when it came to hearing in noise. The worse the high-frequency hearing, the harder it was to pick out speech from the background chatter.

The Takeaway

The main conclusion is that while young people can often ignore the loss of these high-frequency sounds because their brains are so good at compensating, middle-aged adults cannot. For them, this "hidden" hearing loss acts like a magnifying glass, making the natural slowing of the brain's processing speed much more obvious and damaging.

The study suggests that for middle-aged adults who seem to have "normal" hearing on a standard test, checking these extended high frequencies might be crucial. If a middle-aged person is struggling to hear in noisy places, it might not just be "getting older"; it could be that their ears have lost the high notes that help their brain sort out the noise. The researchers found that this loss has no real impact on young adults, but it significantly amplifies the difficulties faced by those in their 40s and 50s.

In short, the paper tells us that the "invisible" part of our hearing is actually very visible when it comes to how well we function in the real world, especially as we move from youth into middle age.

Technical Summary: Effects of Age and Extended High-Frequency Hearing Loss on Auditory Memory, Sequencing, and Speech Perception in Noise in Marathi-Speaking Adults

Problem Statement
Standard clinical audiometry typically assesses hearing sensitivity only within the 250 Hz to 8 kHz range. However, damage to the basal turn of the cochlea often manifests first in the extended high-frequency (EHF) range (above 8 kHz) due to aging or noise exposure, even when conventional thresholds remain normal. While evidence suggests that EHF hearing loss (EHFHL) contributes to real-world listening difficulties, particularly speech perception in noise (SPIN), limited research has examined the combined influence of age and EHFHL on auditory-cognitive abilities such as auditory memory and sequencing. Furthermore, there is a scarcity of data regarding these interactions within Indian populations and Marathi-speaking adults, where validated assessment tools are necessary to ensure ecological validity.

Methodology
The study employed a cross-sectional design involving 80 Marathi-speaking adults with normal conventional audiograms (≤25 dB HL from 250–8000 Hz). Participants were stratified into four equal groups ( $n=20$ per group) based on age (Young: 20–39 years; Middle-aged: 40–60 years) and EHFHL status (Present or Absent). EHFHL was defined as an Extended High-Frequency Pure-Tone Average (EHFPTA) exceeding 26 dB HL at 8, 10, 12.5, and 16 kHz.

Participants were screened to exclude those with auditory processing difficulties, neurological conditions, or systemic comorbidities. The study utilized three primary outcome measures:

Auditory Memory and Sequencing: Assessed using the Auditory Memory and Sequencing Test in Marathi (AMST-M), scoring memory and sequencing of word sequences separately.
Speech Perception in Noise (SPIN): Assessed using the Speech Perception in Noise test in Marathi (PSIN-M), measuring the percentage of correct monosyllabic words presented against four-talker babble at 0 dB SNR.
EHF Audiometry: Conducted at 8, 10, 12.5, and 16 kHz to calculate EHFPTA.

Statistical analysis included non-parametric Mann–Whitney U tests for group comparisons with effect size calculations ( $r$ ), Spearman's rank-order correlations, and multiple linear regression models using age and EHFPTA as continuous predictors.

Key Results
The study identified distinct patterns of performance based on the presence of EHFHL and the age of the participants:

Impact of Age without EHFHL: In adults with normal EHF thresholds, age significantly affected only auditory memory ( $p=0.001$ , medium effect size). No significant age-related differences were found for auditory sequencing or SPIN in this subgroup.
Impact of Age with EHFHL: In adults with EHFHL, age significantly impacted all three outcomes: auditory memory, sequencing, and SPIN ( $p<0.001$ for all), with large effect sizes ( $r = 0.573–0.668$ ). This indicates that EHFHL amplifies age-related deficits, extending them to include sequencing and SPIN, which remained intact in the absence of EHFHL.
Impact of EHFHL by Age Group:
- Young Adults: EHFHL had no significant effect on any outcome compared to young adults without EHFHL. This suggests sufficient auditory-cognitive reserve in younger individuals to compensate for early EHF threshold elevation.
- Middle-Aged Adults: The presence of EHFHL was associated with significantly poorer performance across all three measures compared to middle-aged adults without EHFHL. The effect was largest for SPIN ( $r=0.751$ ), followed by auditory memory ( $r=0.582$ ) and sequencing ( $r=0.498$ ).
Regression Analysis: Multiple linear regression revealed that age was the stronger predictor for auditory memory ( $\beta = -0.456$ ) and sequencing ( $\beta = -0.316$ ). Conversely, EHFPTA was the stronger predictor for SPIN ( $\beta = -0.446$ ). The models explained approximately 33.5% of the variance in auditory memory and 31.2% in SPIN.

Key Contributions

Additive Effect of Age and EHFHL: The study demonstrates that while age alone primarily affects auditory memory in clinically normal-hearing adults, the combination of aging and EHFHL creates an additive burden that significantly degrades auditory sequencing and speech perception in noise.
Critical Age Threshold: The findings highlight that the functional consequences of EHFHL are not immediately apparent in young adults but become clinically significant in middle-aged adults (40–60 years), where compensatory mechanisms appear to diminish.
Differentiated Predictors: The research distinguishes between the drivers of different auditory-cognitive tasks, showing that while cognitive aging drives memory and sequencing declines, spectral resolution (EHF sensitivity) is the primary driver for speech-in-noise difficulties in this population.
Cultural Validity: By utilizing Marathi-validated tools (AMST-M and PSIN-M), the study provides a methodological framework for assessing these deficits in non-English speaking populations, addressing a gap in existing literature.

Significance and Claims
The authors conclude that EHF audiometry is clinically important for middle-aged adults, even when conventional audiograms are normal. The study posits that routine assessment should include EHF testing to identify early functional auditory changes that standard protocols miss. Specifically, the large effect size observed for SPIN in middle-aged adults with EHFHL suggests that EHF spectral cues are critical for speech segregation in noise, and their loss significantly increases listening effort and cognitive load.

The paper asserts that auditory memory is the most consistent marker of age-related decline in the absence of EHFHL, whereas sequencing and SPIN deficits emerge primarily when age-related decline coincides with EHFHL. Consequently, the authors advocate for the inclusion of EHF audiometry in routine audiological monitoring for middle-aged adults to better predict and manage functional listening difficulties. The study acknowledges limitations, including its cross-sectional design and single geographic origin, suggesting that future longitudinal research is needed to track the trajectory of these changes.

The Hidden Frequency and the Aging Ear

The Study: Tuning into the Invisible

What They Found: The Age Gap and the Hidden Noise

The Takeaway

Technical Summary: Effects of Age and Extended High-Frequency Hearing Loss on Auditory Memory, Sequencing, and Speech Perception in Noise in Marathi-Speaking Adults

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