The Early Aging Temporal Processing: Evidence from Temporal Modulation Transfer Function with Background Noise

Aditaya Narayana  Singh; Prajwal Kumar  Eranna; Jayashree S  Bhat

doi:10.18502/avr.v35i1.20578

Aditaya Narayana Singh Nitte (Deemed to be University), Nitte Institute of Speech and Hearing, Mangalore, India
Prajwal Kumar Eranna Nitte (Deemed to be University), Nitte Institute of Speech and Hearing, Mangalore, India
Jayashree S Bhat Nitte (Deemed to be University), Nitte Institute of Speech and Hearing, Mangalore, India

DOI: https://doi.org/10.18502/avr.v35i1.20578

Keywords: Early changes; aging, temporal processing; temporal modulation transfer function; modulation detection

Abstract

Background and Aim: Temporal processing deficits are reported to contribute to speech perception difficulties in noise. However, traditional temporal resolution tasks, which are often conducted in quiet conditions, may not always reflect a noticeable decline in temporal resolution abilities until individuals reach their late 40 s or 50 s. By examining temporal processing under background noise, this study aimed to provide new insights into the early manifestations of age-related auditory decline and its impact on speech perception in noise among early adulthood.

Methods: A Cross-sectional 4 x 2 mixed comparative research design was implemented, with four levels of between-group variables (age groups) and two levels of testing conditions (quiet vs noise). 80 participants with normal hearing were recruited across four groups within the age range of 20–40 years. Temporal Modulation Transfer Function (TMTF) was measured under a quiet and noisy background for broadband stimuli for nine modulation frequencies (2 Hz–512 Hz). Signal-to-Noise Ratio 50% (SNR50) was measured using an adaptive procedure for nonsense words.

Results: One-way analysis of variance revealed a significant age-related decline in TMTF after 35 years, with a more pronounced deterioration in noisy conditions, particularly at higher modulation frequencies. Paired t-test revealed a significant impact of background noise became more evident after this age. Additionally, correlation analysis showed a stronger relationship between peak sensitivity, bandwidth, and SNR50 in noisy conditions.

Conclusion: The study concludes that assessing temporal processing in background noise can effectively detect early changes and better explain speech perception difficulties in noisy environments.