Verbal auditory closure and the speech perception in noise (SPIN) Test.

Ability to utilize auditory contextual information to facilitate speech-recognition verbal auditory closure is postulated to be a specific factor or primary mental ability, separable from general intelligence or other mental functions. This paper proposes that measurement of verbal auditory closure provides useful clinical information. Because the Speech Perception in Noise (SPIN). Test allows separate scores for understanding of sentences that contain contextual information and of those that do not, the SPIN Test provides a good measure of verbal auditory closure. Now that an authorized version of the revised SPIN Test is commercially available, it is appropriate to review published information about reported performance of different listener groups on this instrument and to propose additional research questions that deserve investigation.

Functional brain imaging and hearing.

Functional brain imaging techniques such as PET, SPECT, and functional MRI have frequently been applied to the study of speech, language, and cognition, but have seldom been used in investigations of hearing. Even the limited research that combines functional brain imaging and acoustic stimuli has often been concerned with processes other than audition, such as attention. This paper provides brief descriptions of these currently available functional brain imaging procedures and gives examples of what may be learned about hearing from their applications. Possible reasons for the limited use of functional brain imaging in studying hearing are explored because attention to these issues may enhance interest in the use of brain imaging for investigating the neurophysiology of hearing. Several potential research questions that apply functional brain imaging while measuring psychoacoustic performance are considered briefly and strategies for increasing brain imaging research on psychoacoustic topics are discussed.

Effectiveness of self-help smoking cessation guides for firefighters.

Most smokers would prefer to quit smoking on their own. However, among specific blue-collar occupations it is not known whether self-help techniques will be effective or even used to help smokers quit smoking. In this study we evaluated the effectiveness of a self-help smoking cessation guide designed specifically for firefighters (FF) and compared it with the American Lung Association (ALA) guide designed for the general public. We hypothesized that a shorter guide (FF), written in the jargon of the fire service, and formatted as a workbook would be more effective. One hundred five firefighters randomly received either the ALA or FF guide after having an annual physical examination. Twelve percent of the ALA group and 11% of the FF group quit smoking after the physical examination but before receiving the guides. We found no relationship between the specific guide that the firefighters received and subsequent smoking status. Few firefighters reported filling out pages of the ALA guide (11.9%) or the FF guide (17.8%). For smokers who have not reached the active stage of quitting smoking, guides may not be a factor in quitting. Screening smokers to determine their "stage of change" at the physical examination may increase the effectiveness of self-help guides.

Fine-grained auditory discrimination: factor structures.

This research tested the hypothesis that as children's language development matures, factor-analytic structural changes occur that are associated with measurements of fine-grained auditory discrimination, receptive vocabulary, receptive language, speech production, and three performance subtests of the WISC-R. Among 6- to 7-year-old children, the percent of total variance attributed to the factor defined by fine-grained auditory discrimination measures was approximately 43% for children who were intellectually impaired (Experiment 2), 27% for youngsters who had language-learning problems, and 16% for regularly progressing children (Experiment 1). The WISC-R subtest scores, generally, did not load on the auditory discrimination factor. The difference in variance explained by the auditory discrimination factor was interpreted as representing greater relative importance of auditory discrimination among children with less-well-developed language competencies than among children with more mature language skills. This interpretation was strengthened by the finding of no distinct auditory discrimination factor for 8- to 11-year-old children who were either regularly progressing or language-disabled even though the language/speech factor at this age closely resembled that found among younger children. Results were consonant with Ackerman's (1987) model, suggesting that task-specific variance associated with tasks that remain resource-dependent may diminish after practice and experience.

Asymmetrical discrimination of narrow-band stimuli.

A three-interval, forced-choice procedure that obtained complete psychometric functions was used to study frequency discrimination for 13-item continua of impulse-generated, narrow-band, buzz-like, steady-state sounds. For all subjects and durations, discrimination relative to the highest center frequency (1060 Hz) stimuli was better than discrimination relative to the lowest center frequency (940 Hz). This result is not in consonance with traditional reports of pure tone frequency discrimination and is not readily explained. However, additional experiments with similar stimuli replicated these findings.

Discrimination of second-format-like frequency transitions.

Discrimination of two types of simulated single-second-format frequency transitions was studied, transitions where members of a stimulus set shared the same onset frequency and transitions where stimuli of a set shared the same offset frequency. Experiment 1 employed an adaptive procedure to measure just-noticeable differences for transitions that increased in frequency. Experiment 2 obtained complete psychometric functions, based on a three-interval, forced-choice procedure, for transitions that either increased or decreased in frequency. In both experiments, better discrimination occurred for longer stimuli, measured in hertz/millisecond, and for transitions that shared the same onset frequency. There were no differences, in Experiment 2, between discrimination of rising and falling transitions. Results are considered from several theoretical perspectives.

Perception of gated, highly familiar spoken monosyllabic nouns by children with and without learning disabilities.

A forward-gating procedure employing highly familiar monosyllabic words was used in auditory testing of age- and gender-matched children with learning disabilities and normally achieving children aged 8 to 11 years. The portion of the word presented, or "gate," was longer on each successive trial. Nondisabled children identified an average of one more word than the children with learning disabilities, but the mean duration required for word identification did not differ between groups. Better receptive vocabulary scores were associated with identification of words at shorter durations only among the children with learning disabilities. The two groups of children had similar numbers of different meaningful-word and different non-word incorrect responses. The children with learning disabilities exhibited poorer fine-grained auditory discrimination than a control group of nondisabled children. The study concluded that auditory closure skills for the gating task were as good among children with learning disabilities as among nondisabled children, but that sensory discrimination problems may contribute significantly to the learning difficulties of the former group.

Fine-grained auditory discrimination and performance on tests of receptive vocabulary and receptive language.

This research investigated the relation between children's performance on two measures of receptive language and children's auditory discrimination of consonant-vowel sounds having frequency and temporal acoustic differences. The measures of fine-grained auditory discrimination produced significant multiple regression coefficients against both receptive vocabulary (Peabody Picture Vocabulary Test-Revised) and receptive language (Token Test for Children) scores. Validation analyses conducted by predicting receptive vocabulary and language scores for a new sample of children and relating them to the actual scores led to significant outcomes. It was concluded that fine-grained auditory discrimination is particularly important in the relatively early stages of language learning.

Discrimination of rising and falling simulated single-formant frequency transitions: practice and transition duration effects.

Two experiments evaluated discrimination of simulated single-format frequency transitions. In the first experiment, listeners received practice with trial-by-trial feedback in discriminating either rising or falling frequency transitions of three different durations (30, 60, and 120 ms). Transitions either occurred in isolation or were followed by a steady-state sound matched in frequency to the transition end point. Some improvement in discrimination over practice runs occurred for the shortest transitions. Whether performance was evaluated at the beginning or end of practice, there were no differences attributable to transition direction or to whether transitions were followed by steady-state sound. Discrimination, however, was significantly better for the longest transitions. Just noticeable differences (jnd's) for the longest transitions, measured in Hz at transition onsets, were of approximately the same magnitude as jnd's for steady-state sounds that were equal in frequency to the midpoints of the transitions. Subjects of the second experiment discriminated the longer rising and falling transitions, but did not receive extensive practice. Results of experiment 2 replicated results of experiment 1 in showing similar jnd's. Experiment 2 also showed no differences attributable to transition direction or to the presence of the steady-state sound following transitions.

Age differences in discrimination of simulated single-formant frequency transitions.

We studied auditory discrimination of simulated single-formant frequency transitions that resembled portions of certain speech consonants. Significant age differences in transition discrimination occurred; both children and older adults required larger acoustic differences between transitions for discrimination than did teenagers/young adults. Longer transitions were more easily discriminated than shorter transitions by all listeners, and there were no differences between discriminations of rising and falling transitions. Teens/young adults and older adults, but not children, required larger frequency differences to discriminate frequency transitions followed by a steady-state sound than for transitions alone. There were also age differences in discrimination of steady-state sounds. These developmental-perceptual differences may help explain why children and older adults who have good pure-tone sensitivity may experience difficulty in understanding speech.

Fine-grained auditory discrimination in normal children and children with language-learning problems.

Two large groups of children--one progressing normally in school and the other exhibiting language-learning problems--were tested on a set of fine-grained auditory discrimination tasks that required responding to small acoustic differences. Discriminant analysis procedures, using only results for the auditory tasks, correctly classified nearly 80% of the 6- and 7-year-olds and nearly 65% of the 8- to 11-year-olds according to their school placements. Percentages of correct classifications increased to 87% and 75% when measures of receptive vocabulary (PPVT-R), receptive language (the Token Test for Children), and the Digit Span, Coding, and Block Design subtests of the WISC-R were also included in the discriminant functions. Results suggested that fine-grained auditory discrimination makes a major contribution to language learning, particularly in the early elementary school years.

Longitudinal changes in auditory discrimination in normal children and children with language-learning problems.

Two groups of children--one progressing normally in school and the other exhibiting language-learning problems--were tested in each of 3 years on a set of fine-grained auditory discrimination tasks that required listening for small acoustic differences. Children's ages ranged from 6 to 9 years; there were 21 children per group. The children with language-learning problems, despite having normal intelligence and normal pure-tone sensitivity, showed poorer auditory discrimination than normal children for temporally based acoustic differences. This effect continued across the 3 years. Children with language-learning problems also exhibited poorer receptive vocabulary and language performance as well as more deviations from standard Midwest articulation than children making normal progress in school. All children had hearing within the normal range, but at some frequencies there was a significant association of pure-tone sensitivity with performance on the auditory discrimination, receptive language, and speech production tasks.

Discrimination and response bias for CV syllables differing in voice onset time among children and adults.

A previous experiment demonstrated age-related differences in voice-onset-time (VOT) discrimination when an adaptive procedure was used and trials were concentrated among pairs of stimuli that were discriminated 50% of the time. The major purpose of this experiment was to determine whether the same types of age effects would be replicated for new groups of subjects and a different task in which all stimuli were presented equal numbers of times. An eight-item, five-formant consonant-vowel (CV) continuum in which VOT ranged from 0-35 ms was used. The same-different task presented all possible pairs of CV syllables in which VOT differed by 10 and 20 ms and an equal number of catch trials that contained identical CVs. Results showed that children displayed poorer discrimination than adults for CV pairs differing by both time intervals. Adults displayed a somewhat greater tendency to respond "same" than children. The outcomes supported results of the previous study and were interpreted as representing true age-related differences in VOT discrimination.

Adult and child discrimination of CV syllables differing in voicing onset time.

The purpose of this experiment was to determine whether age-related differences would be observed for discrimination of synthesized, 5-formant consonant-vowel syllables that differed in voicing onset time (VOT) of the initial consonant. Just noticeable differences (JNDs) were measured relative to the end points of the stimulus continuum, using a "same"-"different," adaptive procedure with trial-by-trial feedback/reinforcement and "catch" trials, in which members of the stimulus pair were identical syllables. 6-8-year-old children required significantly longer VOTs for syllabic discrimination than did adults. Adults' JNDs relative to [pa] at the end of the stimulus continuum with longer VOTs were significantly larger than their JNDs relative to [ba], as would be expected on the basis of psychoacoustic considerations, but neither 6-8-nor 8-11-year-old children showed this trend. Performance on "catch" trials for both groups of children was significantly poorer than for adults. Outcomes corresponded to results of other investigations that have reported that children require more acoustic information than adults to achieve the same performance criterion.

Syllable identification by children and adults for two task conditions.

Both 6-year-old children and adults showed as good performance on a syllable identification task for a test condition having more trials per test run and a lower overall level of positive reinforcement as they did for a condition with fewer trials per test run and a higher, overall level of positive reinforcement. Differences between identification thresholds of children and adults are interpreted as reflecting age-related differences in speech processing rather than differences in responding to the test situation.

Word frequency effects for a closed-set word identification task.

Previous work demonstrated that adults achieved higher performance scores than young children on a 4-alternative forced-choice (4 AFC), picture-pointing speech identification task even though all stimuli (words and pictures) had been developed to be familiar to 3-year-old inner-city children. It was hypothesized that these results reflected 'word frequency effects' in the sense that, even though children knew the words, adults had much greater experience with the stimuli and, consequently, required less acoustic information for correct performance. In the current study, this hypothesis of word frequency effects was tested by creating new materials in which the stimulus items (recorded words and pictures) remained the same but new picture foils representing less frequently occurring words replaced the incorrect response alternatives. According to Broadbent's word frequency, response bias views, it was hypothesized that adults would show improved performance on the modified test materials, compared to the original ones. Data supported this hypothesis and also showed that, in children, the magnitude of word frequency effects is related to receptive vocabulary skills. This phenomenon needs to be considered in developing clinical tests of speech or language that have a closed-set format.

Pure-tone sensitivity and ear canal pressure at threshold in children and adults.

Previous investigation have found that young children have poorer pure-tone auditory sensitivity than older children or adults. This study addressed the question of whether these age-related sensitivity differences are attributable to children having middle ear disorders that produce a conductive hearing loss or to differences in ear canal sound pressure at threshold. Results ruled out both of these possible explanations for the age effect.