An auditory Stroop effect for pitch, loudness, and time.

Increased reaction time to pitch, loudness, or duration of an auditorily presented word whose meaning is in conflict with the response label (i.e., high/low, loud/soft, or fast/slow) demonstrates an auditory Stroop effect. Fifteen normal adults participated in an auditory Stroop test. Analysis of reaction time data supports the existence of an auditory Stroop effect for pitch and loudness, but not duration. The interaction between psychoacoustic and semantic attributes of speech stimuli is discussed.

The Lombard effect on alaryngeal speech.

The need to train alaryngeal speakers to use increased vocal intensity has been noted in the literature. One untested technique is to evoke an intensity increase by applying masking noise to the ears of the talker. The purpose of this study was to investigate the Lombard effect on the speech of esophageal talkers, artificial larynx users, and normal speakers. The subjects read aloud a variety of materials first in quiet then while being subjected to 100 dB SPL noise delivered through earphones. The resulting sound pressure values were obtained by measuring the peak values of all syllables spoken by each talker. The results indicated that the esophageal talkers produced the highest intensity increase in the noise condition followed by the normal talkers and the artificial larynx talkers. Coarticulatory and duration effects on alaryngeal and normal speech are also reported. Clinical implications are discussed.

Lateralization of rapid auditory sequences.

Subjects were trained to manually respond to the presence of a preassigned target order of a two-element sequence in a dichotic presentation. Reaction times to rapid target sequences presented to the right ear were significantly shorter than left ear reaction times. The speech or nonspeech character of the stimulus was not a significant factor. There were no lateral differences in accuracy of response. The lateral differences in reaction time are interpreted as a greater efficiency of processing by the right ear (and by implication, the left hemisphere) when temporal characteristics of the sequences were similar to temporal values found in speech.

Auditory processing of vowels by normal-hearing and hearing-impaired listeners.

"Masking" patterns were obtained in normal-hearing and hearing-impaired listeners using the pulsation-threshold procedure. Synthesized vowel maskers /a/ and /ae/ were presented at various sound pressure levels and alternated witha sinusoidal probe of a given frequency at a repetition rate of 4 Hz, T = 250 msec. Simultaneous-masking patterns also were obtained in one normal-hearing listener. The vowel pulsation patterns (VPPs) for the normal-hearing listeners closely resembled the acoustic spectra of the vowel maskers. Neither the pulsation patterns for the hearing-impaired listeners nor the simultaneous-masking patterns for the normal-hearing listener preserved the contour of the vowel spectra. These results are interpreted in terms of suppression effects, which have been observed only with nonsimultaneous-masking paradigms in normal-hearing listeners and have not been observed in listeners with a cochlear hearing loss. The effects of increased masker level were the same for both groups of listeners and are discussed in terms of upward spread of masking and a masking function with a slope less than 1.0.

Frequency and intensity effects on ear dominance for tone bursts.

Normal-hearing Ss (N = 20) listened to dichotic pairs of 20-msec tones at 0.4, 1.5, or 3 kc/s differing by 76, 224, or 376 c/s between the two ears and also differing by 0, 15, or 35 db in SPL (the more intense tone always at 80 db SPL). S judged each pair "high-low" or "low-high" in pitch. Earlier investigations have shown that many normal-hearing Ss demonstrate a dominance for pitch perception of one ear over the other which is unaltered by large interaural intensity differences. In this study, ear dominance could be modified by a change in frequency location or interaural frequency difference of the dichotic stimuli. The effect of interaural level differences could be seen at all frequency conditions, but was strongest at low frequencies. It was suggested that ear dominance on this perceptual task is governed by several characteristics of the auditory system, including loudness perception, dichotic fusion, and frequency selectivity, as well as some as-yet ill-defined binaural processes.

The relationship between loudness and reaction time in normal hearing listeners.

Equal-loudness contours were constructed from magnitude estimation judgements in 10 normal-hearing listeners. Equal-latency contours were constructed from auditory reaction time measurements in these same listeners. the stimuli were pure tones ranging from 250-4000 Hz in octave intervals. Equal-loudness contours were in good agreement with those obtained by previous researchers, and the equal-latency curves were in good agreement with the equal-loudness contours.

Changes in number and type of errors on repetition of acoustically distorted sentences as a function of age in normal children.

The intelligibility of recorded sentences, distorted by binaural switching, interruption, and low-pass filtering, was investigated in 53 children ranging in age from five to eleven and in adults. All had normal hearing. The sentence vocabulary was pretested for comprehension, articulation errors were evaluated in a way so as not to influence test results, and length and structure of the sentences were controlled. The results indicated that although the performance of children increased with age, the 11-year-old group had not attained adult performance. Error analyses showed that most errors for all age groups were acoustically unrelated to the distorted message, although adults made more acoustically related errors than did children. When children made errors in sentences, other errors (e.g., substitutions) were made to preserve the syntax or semantic integrity of the message.

Influence of acoustic reflex on acquisition of temporary threshold shift from short duration noise bursts.

The purpose of this study was to examine the relationship between the acoustic reflex elicited by short duration noise bursts and the resultant temporary threshold shift. Acoustic reflex responses were monitored during the presentation of fatiguing stimuli consisting of interrupted and continuously presented octave noise bands (500--1000 and 1500--3000 Hz) presented at 98 dB sound pressure level. For interrupted stimuli, burst duration was maintained at 100 msec while five different off times ranging from 50 to 450 msec (in 100-msec steps) were used. Exposure duration was varied to equate total energy received in each off-time condition. Noise exposures having shorter off times produced significantly more reflex activity than did exposures with longer off times. Greater impedance changes were elicited by the high band noise than by the low band noise exposure. Although the high band noise tended to produce greater reflex activity it also produced significantly more temporary threshold shift. Differences in the amount of temporary threshold shift produced by the two noise bands could not be attributed to the effects of reflex contraction.

Periodicity pitch perception of retarded children.

In order to expand the body of information concerning auditory function in the presence of the generalized cortical dysfunction associated with severe mental retardation, the discrimination of periodicity pitch signals by nonverbal severely retarded children and adults of normal intelligence was examined using an operant conditioning adaptation of the psychophysical method of constant stimulus differences. The periodicity pitch difference limens (DLs) based on changes in repetition rate were compared with frequency DLs obtained from low (150 Hz) and high frequency (2200 Hz) sinusoids. Periodicity pitch signals were generated by gating a 2200-Hz sinusoid over a range from 141 to 159 pulses per sec and passing the signals through a narrow band-pass filter to ensure no low frequency energy was present. The DLs (75% correct discriminations) were computed from the three types of discrimination performance curves. Standard errors of the means were small and retarded subjects showed good test-retest reliability. The results indicated that the simple and complex pitch discrimination abilities for both normal and retarded subjects were similar.

Perception of periodicity pitch by hearing-impaired listeners.

The perception of periodicity pitch was examined in normal and hearing-impaired listeners. Hearing-impaired listeners exhibited varying degrees of damage to the basal (steep and gradual high frequency hearing losses) and apical (low-frequency hearing losses) portions of the cochlea. The four groups of listeners matched the pitch of the sinusoids to the pitch of air conduction pulse trains with pulse repetition frequencies of 150 and 250 located at center frequencies of 2000 and 4000 Hz. Normal-hearing listeners had no difficulty in perceiving the periodicity pitch. Hearing-loss subjects presented complex response patterns that seemed related to damage to high-frequency (basal) portions of the cochlea, but in general, did not make pitch matches corresponding to the wave-form periodicity. The data support experiments suggesting that the basal portion of the cochlea is responsible for the detection of periodicity pitch. It is also suggested that place information may influence pitch recognition for hearing-imparied listeners.

Middle ear muscle activity during speech in stapedectomized and laryngectomized subjects.

Middle ear muscle responses associated with speech production were observed in normal-hearing, stapedectomized, and laryngectomized subjects. Impedance changes associated with speech production were monitored by an electroacoustic impedance bridge simultaneously with vocal output. Results from stapedectomized subjects indicate that the tensor tympani muscle contracts prior to vocalization and is part of the neurological pattern of speech production. Data collected from laryngectomized subjects suggest that the presence of sensory fibers from the larynx is not a prerequisite for middle ear muscle activity during speech production.

Anticipatory middle-ear reflex activity from noisy toys.

Middle-ear reflex activity was measured in 14 listeners in response to visual and acoustic exposure to each of seven noisy toys (such as a cap gun, party horn, cow bell, and so forth). Anticipatory middle-ear reflex (AMER) activity was a common occurrence. Normal middle-ear reflex generally occurred after the sound exposure. AMERs generally occurred in the two seconds prior to sound exposure but as early as 10 seconds before sound exposure. Loudness ratings and exposure SPLs were obtained. The presence of acoustically evoked middle-ear (ME) reflex activity and AMERs to the toys was generally unrelated to SPL or reflex threshold. Many reflex responses occurred in response to exposure SPLs below reflex threshold and with low anticipated loudness rating.