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Biomedical subjects

J M Moore

Publications and source records attributed to J M Moore.

107 records · Page 6Linked to original sources

Application of visual reinforcement audiometry (VRA) to low-functioning children.

Visual reinforcement audiometry (VRA) was studied on a group of low-functioning children in an ongoing clinical program. After establishing the specific reinforcing value of the visual stimulus, threshold assessments were made. VRA was an effective test procedure for most of the children tested, providing their developmental ages reached approximately the 10-month level or higher. On the basis of VRA thresholds and tympanometry, 52% of the children seen were referred for medical evaluation. A variation of VRA was used to assess syllable-discrimination performance on a pilot basis. Results are discussed in terms of the potential use of VRA to assess infant spedch-sound discrimination in addition to its current use as an indicator of hearing sensitivity.

Audiometry↗

Rapid and sensitive gas chromatographic quantitation of morphine codeine and O6-acetylmorphine in illicit heroin using an electron capture detector.

Morphine, codeine and O6-acetylmorphine are reacted with heptafluorobutyric anhydride, rendering them suitable for electron capture detection and quantitation. The fluorinated derivatives are extracted from an acetonitrile-sodium bicarbonate solution into light petroleum in a rapid one-step extraction procedure. The derivatives are chromatographed on a stationary phase of 3% OV-17 on Gas-Chrom Q. Morphine, codeine and O6-acetylmorphine can be readily quantitated in heroin at levels as low as 0.001%, 0.01% and 0.01% respectively. Reproducibility, linearity and recovery studies are described.

Chromatography, Gas↗

Visual reinforcement audiometry (VRA) with young Down's syndrome children.

Visual Reinforcement Audiometry (VRA) was investigated with 41 Down's syndrome subjects between the ages of six months and six years. The VRA procedure involved monitoring a head-turn response to a complex noise signal presented in a sound field with an ascending presentation paradigm and reinforced by a complex visual reinforcer. Twenty-four of the infants and young children also were evaluated with the Bayley Scales of Infant Development (BSID) to allow for analysis of the efficacy of VRA as a function of developmental age. Results were as follows: (1) 28 (68%) of the infants and young children initially oriented towards the source of the auditory stimulus, (2) only a few of the subjects who did not initially orient could be taught to respond, (3) of the children who initially oriented or were taught to respond, thresholds were obtained on a large number (81%) in one visit, and (4) a systematic relationship was demonstrated between consistency of subject response using the VRA technique and BSID Mental Age Equivalent with 10 months being the critical age for determining the potential success of the procedure. In addition, the results implied a higher incidence of hearing loss in the Down's syndrome subjects than found in normal pediatric population.

Age Factors↗

Visual reinforcement of head-turn responses in infants under 12 months of age.

The effect of complex visual reinforcement (animated toy animal) on auditory localization responses of infants below 12 months of age was studied. Sixty infants served as subjects and each subject received 30 presentations of complex noise at suprathreshold level. After each response to an auditory signal, one-half of the infants (experimental group) received complex visual reinforcement and the other half (control group) received no reinforcement. The experimental and control groups were further subdivided into three age groups: four months, five and six months, and seven to 11 months. Visual reinforcement produced significantly more responses (head turn) than no reinforcement for the two older age groups. There was no significant difference between the experimental and control conditions at four months of age.

Age Factors↗

Developmental changes in speech discrimination in infants.

A visually reinforced infant speech discrimination (VRISD) paradigm is described and evaluated. Infants at two ages were tested with the new paradigm on the following speech contrasts: [sa] vs [va], [sa] vs [fa], [sa] VS [za], [as] vs [a:s], vs [a:z], [at] vs [a:d], [a:t] vs [a:d], [at] vs [a:t], [fa] vs [thetaa]and [fi] vs [thetai]. The data reported are compared with data on the same speech contrasts obtained from three month olds in a high-amplitude sucking paradigm. Evidence suggesting developmental changes in speech-sound discriminatory ability is reported. Results are interpreted in light of salience of available acoustic cues and in terms of new methodological advances.

Age Factors↗

Auditory localization of infants as a function of reinforcement conditions.

The influence of four reinforcement conditions on the auditory localization behavior of normal infants was studied. Forty-eight infants 12 to 18 months of age were assigned to one of four groups of 12 subjects each. All received 30 presentations of complex noise at suprathreshold level. After each response to the stimulus, Group 1 received no reinforcement, Group 2 received social reinforcement, Group 3 received "simple" visual reinforcement (a blinking light), and Group 4 received "complex" visual reinforcement (an animated toy animal). The two visual reinforcement conditions produced the most localization responses, followed in order by the social reinforcement and no reinforcement conditions. These results indicate that auditory localization behavior of infants is influenced by reinforcement and that the extent of this effect is related to the type of reinforcement employed.

Acoustic Stimulation↗