Comparing hearing-impaired and normal listeners requires controlling for both sensation level and absolute level

Evidence

Equating the stimuli used in studies that compare performance between groups of listeners with different hearing levels can be very difficult. Presenting sounds at equal sensation level sounds appealing, but the internal representations of the sounds likely differ between two groups due to loss of cochlear nonlinearity. As a result, we may not be comparing “apples to apples.” Studies also frequently use noise-masking to elevate thresholds in listeners with normal hearing in an attempt to deal with this problem. This experimental manipulation is considered to yield more valid comparisons between the two groups of listeners than equating sensation level, but also has limitations. Listeners with normal hearing must conduct the perceptual measurements in the presence of an audible noise masker. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1089

Listeners were presented with sentences taken from the AZBio speech corpus (Spahr et al. 2012 ). The sentences were presented to the HI listeners at an overall rms level of 85 dB SPL. The sentences were presented to the NH listeners at two different levels: in the equal-SL condition, the sentences were presented at 40 dB above the detection threshold of the speech for the NH listeners, similar to the sensation level (SL) of the 85-dB SPL speech for the HI listeners; in the equal-SPL condition, the speech was presented at 85 dB SPL. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2177

Categorization

• DEFINE: Explains the experimental-limitation logic behind ‘apples to apples’ comparisons in hearing psychophysics — core methodology for reader’s goal.
• QUESTION: Does the noise-masking simulation distort perception in ways beyond threshold elevation, biasing the control condition? Worth chasing.
• corroborated: 2 independent passages support this claim — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1089; Dijk, Pim van, Physiology, Psychoacoustics and…, 2177