Even enlarged pinna cues leave hearing-impaired localization far below normal

Evidence

One potential solution to this problem is to provide hearing-aid users with artificially enhanced pinna cues—as if they were listening through oversized pinnas. In the present study, it was tested whether test subjects were better at discriminating spectral patterns similar to enlarged-pinna cues. The enlarged-pinna patterns were created by transposing (T) generic normal-sized pinna cues (N) one octave down, or by using the approach (W) suggested by Naylor and Weinrich (System and method for generating auditory spatial cues, United States Patent, 2011). The experiment was cast as a determination of simulated minimum audible angle (MAA) in the median saggital plane. 13 test subjects with sloping hearing loss and 11 normal-hearing test subjects participated. The normal-hearing test subjects showed similar discrimination performance with the T, W, and N-type simulated pinna cues, as expected. However, the results for the hearing-impaired test subjects showed only marginally lower MAAs with the W and T-cues compared to the N-cues, while the overall discrimination thresholds were much higher for the hearing-impaired compared to the normal-hearing test subjects. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3050

While the HI group showed an improved ability to discriminate enhanced pinna cues as compared to normal pinna cues, the improvements were not as large as expected, and performance was still substantially poorer than that observed in the NH group. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3134

When the two data sets are compared (see Fig. 6 ), it is noteworthy that even though the use of enhanced cues improves the HI performance in the MAA measurements (from around 30° to around 20°), the mean performance with enhanced cues is still substantially poorer than NH mean performance, which is around 10° with all three types of cues. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3124

It may be questioned whether improving the MAA from 30° to 20° will result in any perceivable real-life benefit, but answering this question will obviously require further testing including training test subjects to exploit modified pinna cues. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3124

Categorization

• QUESTION: Why do enlarged-pinna cue transposition cues give so little benefit to hearing-impaired listeners, when the rationale for them seems strong?
• CANDY: A neat elevator note: making ears bigger helps impaired listeners localize sound, but never as well as normal hearing does.
• corroborated: 6 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 3050; Dijk, Pim van, Physiology, Psychoacoustics and…, 3134; Dijk, Pim van, Physiology, Psychoacoustics and…, 3124
• XREF: connects to: Oversized-pinna cue simulation barely improves vertical localization for hearing-impaired listeners — Dijk, Pim van, Physiology, Psychoacoustics and…, 3048; Hearing impairment makes fine high-frequency pinna cues imperceptible; Enhanced pinna cues only partially close the spatial-resolution gap in hearing-impaired listeners — Dijk, Pim van, Physiology, Psychoacoustics and…, 3133 (+9 more)

Broader Connections

• Hearing aids fail to restore sound localization in many listeners #corroborates (0.90)
• Hearing aids distort localization cues and often worsen localization #corroborates (0.85)
• Auditory nerve damage degrades sound localization by corrupting ILD and ITD cues #corroborates (0.80)
• Sound localization from pinna cues is learned and specific to each person’s ear shape. #complicates (0.75)
• Head-related transfer functions encode how the head and pinna shape spatial hearing #qualifies (0.72)