Uncertainty in location, level and fundamental frequency results in informational masking in a vowel discrimination task for young and elderly subjects

Can You Hear Out the Melody? Testing Musical Scene Perception in Young Normal-Hearing and Older Hearing-Impaired Listeners

“…A central, yet intricate question in the study of hearing loss and ASA concerns the extent to which deficits are due to hair cell dysfunction, that is, cochlear hearing loss, or age-related decline of neural processing along the auditory pathway. Aging has been associated with suprathreshold auditory processing deficits independently of sensorineural hearing impairment (e.g., Eipert et al., 2019 ; Moore, 2015 ). Nonetheless, both factors impede suprathreshold auditory processing abilities, whether measured in psychoacoustical tasks ( Kortlang et al., 2016 ) or with speech reception thresholds (SRTs; Goossens et al., 2017 ).…”

Interaction of spatial source separation, fundamental frequency, and vowel pairing in a sequential informational masking paradigm in Mongolian gerbils.

“…Considering the detection of mistuned harmonics from an otherwise harmonic complex (Klinge & Klump, 2010, 2009), gerbils might be able to perceive the difference in fundamental frequency of 26 Hz (101 Hz and 127 Hz) as presented here. Gerbils are able to process formant frequencies of vowels (Ohl & Scheich, 1997) and to behaviorally discriminate them (Sinnott & Mosteller, 2001; Sinnott et al, 1997), although gerbils’ vowel discrimination thresholds (Sinnott & Mosteller, 2001; Sinnott et al, 1997) are increased in comparison to those in humans (Eipert et al, 2019). Factoring in the known differences of cochlear length and hair cell number per critical band between gerbils and humans this performance difference may already be explained (Klinge, Itatani, & Klump, 2010).…”

“…Referring to similarity-based IM (Lutfi, 1993;Lutfi et al, 2012;Watson, 2005) one might expect less stream segregation resulting in more IM and higher level increment thresholds for the vowels /ae/-/ε/ than for /I/-/i/. However, at least for humans it was already shown that in a vowel discrimination experiment investigating uncertainty-based IM effects, the similarity of vowels did not influence the amount of IM (Eipert et al, 2019). In line, we found no difference between the release from IM for the two vowel combinations /I/-/i/ and /ae/-/ε/ in the gerbil.…”

“…Informational masking (IM; Pollack, 1975) is defined as the compromised ability to perceive and analyze signals from a single source in a clutter of other sounds even if there is no interference of these signals’ excitation patterns in the inner ear (e.g., Durlach et al, 2003; Kidd, Mason, Richards, Gallun, & Durlach, 2008; Lutfi, Chang, Stamas, & Gilbertson, 2012; Watson, 2005). Presenting stimuli as a sequence of temporally separated sounds makes it possible to investigate IM, avoiding simultaneous masking effects (Dolležal et al, 2017; Eipert, Selle, & Klump, 2019; Tolnai et al, 2015; Watson, 2005; Winkler et al, 2003). IM is affected by the similarity between target and masker (similarity-based IM) and the variation of stimulus features from trial to trial (uncertainty-based IM), both modulating discrimination thresholds (e.g., Lutfi, 1993; Watson, 2005).…”

“…IM between competing sound sources can be reduced by various sound features that help to organize and segregate sounds in auditory streams (Bregman, 1990). Speech sounds such as vowel stimuli have already been used to investigate informational masking (Eipert et al, 2019; Roberts, Summers, & Bailey, 2015; Summers, Bailey, & Roberts, 2017) and are characterized by multiple sound features. As has been shown for speech sounds like vowels, the harmonic relation of concurrent sounds helps to segregate sound sources (Micheyl & Oxenham, 2010; Peterson & Barney, 1952; Sinnott, 1989).…”