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This study sought to quantify the effects of varying the degree of ear canal occlusion on pure-tone threshold sensitivity. Thresholds were obtained from each ear of five normal-hearing adults without occlusion, with complete occlusion, and with partial occlusion estimated to be 40-60% and 60-80%. A commercial lubricant was used in the completely occluded condition to eliminate possible acoustic leakage. Results showed a reduction of threshold sensitivity in all occluded conditions, with the greatest effect in frequencies above 1000 Hz. Only in the completely occluded condition were frequencies below 1000 Hz affected. In the partially occluded conditions, thresholds decreased by an average 7.5 dB and 13.0 dB across frequency for the 40-60% and 60-80% conditions respectively. At frequencies above 1000 Hz, the average threshold shifts for the two partially occluded conditions were 10.0 dB and 16.8 dB respectively. The implications of these findings on routine pure-tone audiometric procedures, with specific relevance for industrial hearing conservation programs, are discussed.

Thirty children with hearing loss (HL) and 129 typically developing (TD) children representing comparable ages, vocabulary ability, or phonology skills named pictures while attempting to ignore semantically related or unrelated auditory distractors. The timing relation between the onsets of the distractors and pictures varied. A significant semantic interference effect, that is, slowed naming in the presence of the semantically related distractor, was observed in all groups, suggesting similar categorical knowledge in the HL and TD groups. The time course of semantic interference, however, was protracted in some children with HL, primarily those with unusually slow baseline naming speeds and early ages of identification/amplification of the loss. Thus, children with HL seem to develop normal lexical semantic representations. At the same time, the dynamics of semantic processing appear to be altered by the presence of early childhood HL.

Thirty children with hearing loss (HL) and 129 typically developing (TD) children representing comparable ages, vocabulary abilities, or phonology skills named pictures while attempting to ignore auditory distractors. The picture-distractor pairs were constructed to represent phonologically congruent or conflicting onset relations, for example, the picture "duck" with distractors of /d∧/ or /p∧/, respectively. In children with good phoneme discrimination, congruent distractors speeded naming and conflicting distractors slowed naming, relative to a control condition. Effects were similar in HL and TD subgroups. In children with poorer phoneme discrimination, conflicting distractors did not influence naming in the HL subgroup, regardless of discrimination status, and consistently slowed naming only for discriminated contrasts in the TD subgroup. Phonologic representations appear suitably fine-grained in HL children with good auditory perceptual abilities but may be less well specified, more holistic, and/or less auditory-linguistically based in HL children with poorer auditory perceptual abilities. Results are discussed in terms of the heterogeneous nature of phonologic processing in children with HL.

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