Effect of Contralateral Noise on the Middle Components of the Averaged Electroencephalic Response

Middle-component AERs were obtained from normal-hearing adults to 1000-Hz tone pips at 20 and 40 dB SL and at silent control. A continuous noise at 20, 40, and 80 dB SL and at silent control was presented to the contralateral ear. When the tone pips were at 20 or 40 dB SL, five peaks were identified visually in waveforms constructed by digitally adding AERs across subject and replication. Peak latencies determined from the composite waveforms for each signal-masker condition were used as time points to measure point-to-point amplitudes in individual AERs. The masker at 20 or 40 dB SL did not alter or degrade the AER produced by the tone pip. It was concluded that clinical masking may be used in EEA when the middle components of the AER are employed as a response index.

Sentence Structures of Trainable and Educable Mentally Retarded Subjects

Educable and trainable mentally retarded children were administered a story completion task that elicits 14 grammatical structures. There were more correct responses from educable than from trainable mentally retarded children. Both groups found imperatives easiest, and future, embedded, and double-adjectival structures most difficult. The children classed as educable produced more correct responses than those termed trainable for declarative, question, and single-adjectival structures. The cognitive and linguistic processing of both groups is discussed as are the implications for language remediation.

Effects of Sentence Structure on Sentence Elicited Imitation Responses

This study investigates the effects of sentence structure on the number of error sentences and response latency in a sentence-repetition task. Forty female college students repeated short and long test sentences containing either a single self-embedded or right-branching subject-focus or object-focus relative clause. Sentences were also controlled for deletion of the relative pronoun of the relative clause. Sentence structure was found to affect sentence elicited imitation response accuracy and latency in a manner similar to the effects of structure on ease of comprehension. The findings are consistent with a canonical-sentoid strategy explanation of sentence processing during sentence imitation.

Functional Clauses and Sentence Segmentation

In two experiments subjects listened to a sentence containing a brief tone, then wrote out the sentence and marked the location of the tone. The experimental sentences were biclausal with the tone placed before or after the clause break. The initial clause was either functionally complete or functionally incomplete. Functionally complete clauses contain a complete set of fully specified grammatical relations, while functionally incomplete clauses do not. In Experiment 1 tones were mislocated toward the clause break and the final word of the first clause significantly more often for functionally complete clauses. Experiment 2 replicated this finding holding deep-and surface-structure variables constant. The resulis indicate that functionally complete clauses are better segmentation units during sentence perception than functionally incomplete clauses. Purely structural theories of the units of sentence perception cannot account for this finding.

Effect of Sensorineural Hearing Loss on Loudness Discomfort Level and Most Comfortable Loudness Judgments

A simple up-down adaptive procedure was used to estimate the 50% point on the psychometric function for loudness discomfort level (LDL) and the two functions describing the range of most comfortable loudness (MCL) for listeners with sensorineural hearing impairment. For pure tone and speech stimuli, median LDL and MCL levels were observed at relatively constant SPLs for subjects with hearing loss ≤ 50 dB HL and at progressively higher SPLs with further increase in hearing loss. Correlation analysis verified a statistically significant relationship between LDL and magnitude of hearing loss. The nonlinear relationship between LDL and hearing loss together with the large intersubject variability in the data suggest that prediction of LDL from hearing threshold would often be highly inaccurate. These results also demonstrate that averaging LDL data across a group of subjects with a wide range of hearing loss may lead to inaccurate conclusions regarding the effects of sensorineural hearing loss on LDL.

Maturational Influences on Perception of Coarticulatory Effects

Three experimental groups consisting of ten four-year-olds, ten 11-year-olds, and ten adults were presented with tape-recorded voiceless stop + vowel syllables and subsyllabic segments isolated from the syllables by electronic gating. Subjects were instructed to identify each syllable. Comparisons of the performances of subjects in the three age groups permitted description of maturational influences on the ability to utilize coarticulatory cues in speech perception. The responses of the four-year-olds indicated that they were able to process coarticulatory information for the identification of consonants and vowels from subsyllabic segments. However, their ability to utilize these cues was more limited than that of 11-year-olds and adults. The four-year-old children experienced particular difficulty in the use of aperiodic information. The relative distribution of perceptual cues throughout the portions of the CV syllables was similar for all age groups. The overall phoneme identification accuracy levels of the 11-year-olds appeared to be established at an adult accuracy level. However, differences among all three age groups in regard to consistency of responses, markedness of substitution error preferences, and magnitude of the influence of acoustic stimulus duration on response accuracy suggest that strategies for estimation of phoneme identity may undergo further modification beyond the 11-year-old level before attaining the characteristics of the adult decoding process.

Minimal Reaction Times for Phonatory Initiation

The maximum speed at which voluntary vocal and digital responses can be initiated was investigated in 15 male and 15 female neurologically normal adults using simple reaction time (RT) methodology. All subjects were pretrained to respond as quickly as possible to stimulus onset following a computer-controlled preparatory interval. Voluntary minimal RTs for phonation initiation were studied as a function of (1) stimulus type (auditory and somesthetic), (2) prephonatory vocal-fold position (abducted and adducted), and (3) subject’s lung volume (75%, 50%, and 25% VC). The average minimal vocal RT across subjects was 195 msec, and the fastest recorded vocal RT was 120 msec. Although vocal responses to an auditory stimulus were somewhat shorter than to a somesthetic stimulus, neither these differences nor the RTs between sexes were statistically significant except that females had shorter vocal RTs from an abducted prephonatory vocal-fold position. Shorter vocal RTs were obtained when phonation was initiated at midlung volume than at the lung volume extremes, and for both sexes the average digital RTs were significantly shorter than vocal RTs.

Sampling of Speech Pathology Treatment Activities: An Evaluation of Momentary and Interval Sampling Procedures

Videotaped samples of aphasia treatment sessions were coded, using the Clinical Interaction Analysis System (CIAS), a 39-category system for recording the events that occur in clinician-patient interactions during aphasia treatment sessions. These coded records were then sampled according to various schedules and procedures and the fidelity with which each sampling schedule and procedure represented the content of the entire treatment record was evaluated. In addition, trained observers coded videotaped samples of treatment, using the CIAS with a number of sampling schedules and procedures. The fidelity with which these observers' records represented the content of the treatment sessions sampled was then evaluated. The results of the analysis indicated that momentary sampling at intervals distributed throughout the session generates more accurate records of session content than single longer samples taken from the session, unless those single samples comprise a major part of the session, and that sampling representativeness remains high even when only one event in ten is sampled, if sampled events are uniformly distributed throughout the session.