Biomedical subjects

M P Robb

Publications and source records attributed to M P Robb.

22 records · Page 2Linked to original sources

PubMed1988

Acoustic observations in young children's non-cry vocalizations.

A corpus of 1200 non-cry vocalization samples produced by 14 normal children between the ages of 11-25 months was examined retrospectively. Six percent of the samples yielded instances of either harmonic doubling (HD), fundamental frequency (F0) shift, or biphonation (Bp). These spectrographic features relate to short duration changes in F0, reflecting alterations in vocal fold state characteristics. The HD and Bp segments were perceptually judged to be harsh, while F0 shift closely reflected pitch breaks. The frequency of occurrence of the three acoustic features suggests that they are normally occurring phonatory events in normal children's vocal patterns.

Child Language↗

PubMed1987

Audibility and recognition of stop consonants in normal and hearing-impaired subjects.

The purpose of this study was to examine the effect of spectral-cue audibility on the recognition of stop consonants in normal-hearing and hearing-impaired adults. Subjects identified six synthetic CV speech tokens in a closed-set response task. Each syllable differed only in the initial 40-ms consonant portion of the stimulus. In order to relate performance to spectral-cue audibility, the initial 40 ms of each CV were analyzed via FFT and the resulting spectral array was passed through a sliding-filter model of the human auditory system to account for logarithmic representation of frequency and the summation of stimulus energy within critical bands. This allowed the spectral data to be displayed in comparison to a subject's sensitivity thresholds. For normal-hearing subjects, an orderly function relating the percentage of audible stimulus to recognition performance was found, with perfect discrimination performance occurring when the bulk of the stimulus spectrum was presented at suprathreshold levels. For the hearing-impaired subjects, however, it was found in many instances that suprathreshold presentation of stop-consonant spectral cues did not yield recognition equivalent to that found for the normal-hearing subjects. These results demonstrate that while the audibility of individual stop consonants is an important factor influencing recognition performance in hearing-impaired subjects, it is not always sufficient to explain the effects of sensorineural hearing loss.

Adult↗

PubMed1985

Oral diadochokinesis in hearing-impaired adolescents.

Oscillographic tracings for time-by-count measures of diadochokinetic syllable rate (Fletcher, 1972) were collected from a group of 30 hearing-impaired and five normal-hearing high-school students. Results indicated that hearing-impaired subjects performed significantly slower on all speech-timing tasks than their normal-hearing peers. Within-group differences were identified for the hearing-impaired subjects with respect to speech intelligibility, degree of hearing loss, and gender. The differences, in general, indicate that for varying degrees of hearing loss severity there are speech-timing coordination deficits commensurate to that level.

Adolescent↗

PubMed1985

Developmental trends in vocal fundamental frequency of young children.

Fundamental frequency (F0) values are reported for 14 children between the ages of 11 and 25 months, an age period characterized by changes in physiological and linguistic development. Subjects were grouped into 3-month age intervals reflecting a continuum of physical development and were audiotape-recorded during spontaneous speech productions. Acoustic analysis of average F0 and F0 variability was performed. F0 variability was found to decrease as subject age increased, as did segment durations. The decrease in average F0 across the arbitrary age groups did not reach significance; however, when viewed within the overall developmental period and in comparison with data from other studies of younger and older children, average F0 during this age is consistent with a decreasing trend throughout early childhood.

Age Factors↗