Bradly J. Edgerton

Loudness discomfort levels of hearing-impaired listeners using speech material.

This study was undertaken to: (1) investigate the effects of speech materials on the loudness discomfort level (LDL); (2) assess the intrasession stability among three LDL trials; and (3) examine the relationships between the speech LDL and the pure-tone and spondee thresholds. Ninety-six adults with mild-to-moderate sensorineural hearing loss were tested. Findings showed little or no difference among five commercially available speech materials. Thus, it was concluded that differences in speech materials do not comprise a major source of variability among studies when comparing mean LDL data. Group means may, however, obscure significant individual variations in LDLs that result from differing speech materials. Considerable LDL variability among listeners with similar thresholds was found, suggesting an intolerably high error rate for predictive purposes.

Features from normal and sensorineural listeners' nonsense syllable test errors.

Identification errors for initial consonants of consonants vowels-consonants-vowels from lists A and B of the Nonsense Syllable Test were analyzed for 10 normal-hearing and 8 sensorineural hearing-impaired listeners. The Nonsense Syllable Test stimuli were presented binaurally through earphones at 6 increasing sensation levels. Listeners verbal responses were recorded and transcribed, converted to symmetric confusion matrices, and submitted to analysis of individual differences scaling for symmetrical matrices. Results from 2- through 5-dimensional analyses revealed that voicing, place of articulation, frication, and sibilancy were the salient features used by both listener types in their perceptions of the initial consonants. Findings suggest that consideration of composition of the stimulus set is important when assessing a listeners response to specific speech discrimination tests.

Occlusion effect: Bone Conduction speech audiometry using forehead and mastoid placement

The occlusion effect (OE) was determined for bone conduction speech reception thresholds (SRTs) in 24 normally hearing subjects using forehead and mastoid placement. Results indicated that the OE was about 3 dB greater using forehead as opposed to mastoid placement. The intersubject variability of the OE is similar for the forehead and mastoid positions. The formula for effective masking for bone conduction speech should be equal to the minimum masking level for bone conduction speech plus the air-bone gap of the nontest ear plus 18 dB to account for the OE when using mastoid placement.

Relationship between the Calibration Tone and Speech Volume Unit (VU) Levels for Some Commercially Available Test Tapes

The relationship between the calibration tone and speech volume unit (VU) levels for nine commercially recorded speech tests was studied. Two procedures were used. In procedure 1, experienced clinicians reported observations of four different audiometer VU meters responding to six commercially available speech tests. Differences in magnitude estimates among judges were usually about 1 dB or less. Peak VU level deviations from the zeroed calibration tone were within k1.5 VU except for the Fulton Lewis Jr. recording, which varied by about −4.8 VU. In procedure 2, a video system was used to record precisely VU meter responses to clinical speech materials. Differences between the calibration tones and speech levels were similar to those obtained using multiple observers. Statistically significant (p 5 0.01) differences were found between the speech levels of the commercial test recordings.