Hearing-impaired listeners fail to gain temporal resolution in background noise

Evidence

The results are striking: the straight lines obtained without noise are strongly twisted in such a way that the “mod” value is clearly below the line connecting the masked threshold and the “cont” value, indicating a strongly enlarged temporal-resolution factor, TRF, for normally hearing listeners in background noise. TRF increases to values up to 5 and sometimes almost 10. This means that a normally hearing subject has a very good temporal-resolution factor in noisy backgrounds, as in the case of a cocktail party, and uses it. … The hearing-impaired listener, however, shows different characteristics. … There, the values for “mod” are above the connecting line between “threshold” and “cont”. This means that this listener does not gain in temporal resolution when a background noise is added. The temporal-resolution factor remains 110 H---I---t-H-l dB --- 100 H---I---t-H-l Fig. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1933

The data of a normally hearing listener under corresponding conditions are shown in part (c). There, it becomes clear that the normally hearing subject gains temporal resolution in the background noise if the voice level of the communication partner is increased. The hearing-impaired listener, however, does not gain in the background noise even through the voice level of the partner is increased. This means that the difference in TRF between the normally hearing subject and the hearing-impaired listener may reach values up to ten or even more than that by which the factor is reduced in normal listening. This seems to be a dominant reason why hearing-impaired listeners often have such problems with speech discrimination in noisy conditions (cf. Sect. 16.2.7). — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1943

People with impaired hearing often have difficulties in hearing sounds in a noisy background. This problem is partially a result of the auditory systems reduced capacity to process temporal information in the sound signal. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4151

The hearing-impaired listener, however, shows different characteristics. These are outlined in Fig. 16.:31. In part (a), a temporal masking pattern is shown for the conditions “in quiet” and “with a background noise”. The corresponding temporal-resolution patterns are indicated in part (b). There, the values for “mod” are above the connecting line between “threshold” and “cont”. This means that this listener does not gain in temporal resolution when a background noise is added. The temporal-resolution factor remains 110 H---I---t-H-l dB --- 100 H---I---t-H-l Fig. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1934

Categorization

• XREF: Connects to the cocktail-party problem and to selective-attention research on how normal ears exploit masking release in noise. — connects to: Normal hearing yields a temporal resolution factor near unity; The audiogram cannot predict which hearing-impaired listeners have temporal processing deficits — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1088; Hearing-impaired listeners gain half or less benefit from longer stimulus durations — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1112 (+9 more)
• CANDY: A neat counterintuitive fact: healthy ears actually hear temporal detail better at a noisy cocktail party than in quiet.
• corroborated: 5 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1933; Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1943; Dijk, Pim van, Physiology, Psychoacoustics and…, 4151 (+1 more)

Broader Connections

• The audiogram cannot predict which hearing-impaired listeners have temporal processing deficits #qualifies (0.85) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1088
• Hearing-impaired listeners gain half or less benefit from longer stimulus durations #expands (0.85) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1112
• A narrowband masker selectively taxes temporal coding in hearing-impaired listeners #complicates (0.80)
• Hearing-impaired listeners need higher signal-to-noise ratios than normal hearers do #exemplifies (0.80)
• Hearing impairment disrupts both place and temporal pitch codes #expands (0.75) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1326
• Cochlear gain loss can compensate for temporal coding deficits in AM detection #contradicts (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 5904
• Normal-hearing listeners exploit temporal dips in fluctuating maskers to detect signals. #complicates (0.75) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 551
• Broader cochlear filtering reduces low-frequency noise fluctuations, explaining lost masking release #expands (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2161
• Quiet-versus-narrowband-masked AM threshold differences can isolate temporal coding from cochlear compression #exemplifies (0.70)