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Biomedical subjects

W J Gavin

Publications and source records attributed to W J Gavin.

14 recordsLinked to original sources
PubMed1998

Concurrent and predictive validity of an early language screening program.

The efficacy of screening 2-year-old children for language delay using a parent-report questionnaire was investigated in three studies. The Language Development Survey (Rescorla, 1989) was mailed to 650 families at the time of their child's second birthday. Fifty-three percent of the surveys received by parents were completed and returned. Screening outcomes were then compared, in double-blind fashion, with the results of comprehensive clinical evaluations at ages 2 (N = 64) and 3 (N = 36). Parents' report of the size of their children's expressive vocabularies was highly correlated with clinical language measures at age 2. Children who screened positive performed significantly poorer than children who screened negative on standardized language tests and on measures taken from spontaneous conversation. The screening program demonstrated excellent sensitivity and specificity for identifying language delay at age 2 but somewhat lower levels for predicting developmental status one year later.

Age Factors↗
PubMed1996

Sample size effects on temporal reliability of language sample measures of preschool children.

The present study examined the temporal reliability of four quantitative measurements of operationally defined linguistic behaviors observed in a naturalistic setting. The measures of language production were computed using the Systematic Analysis of Language Transcripts (SALT) software from two 20-minute language samples obtained 3 to 14 days apart for each of 20 preschool-aged children. Samples were edited to different sizes based either on duration (12 or 20 minutes) or on limits of the total number of complete and intelligible utterances (from 25 to 175 in increments of 25). Inadequate reliability was found for the language sample measure, total number of words; hence, the validity of this measure is questionable. In contrast, very high temporal reliability coefficients (r > .92) were obtained for the language sample measures of number of different words, mean length of utterance in morphemes, and mean sentence length in morphemes when derived from a large number (> or = 175) of complete and intelligible utterances. The temporal reliability of these measures reached acceptable levels, not only for research purposes, but for diagnostic purposes as well.

Child, Preschool↗
PubMed1994

Comparison of individual and group/consultation treatment methods for preschool children with developmental delays.

OBJECTIVES: Although alternative treatment methods are becoming more widely discussed and implemented in pediatric occupational therapy, empirical data demonstrating the effectiveness of these treatment methods are lacking. The present study compares the effectiveness of an alternative treatment method (group/consultation) to traditional direct therapy. METHOD: Eighteen preschool subjects classified as developmentally delayed received either individual/direct therapy or group/consultation therapy. Each child was assessed initially and again 7 months later with three standardized tests assessing fine motor and gross motor development, functional skills in the home, and nonverbal intelligence. RESULTS: Subjects in both treatment methods demonstrated significant increases in both fine and gross motor skills with the rate approximating that of the normal distribution of typically developing children. CONCLUSION: There were no statistically significant differences between treatment methods on any of the assessments.

Analysis of Variance↗
PubMed1982

The perception of the sound of silence in early infancy.

When brief periods of silence are inserted between the /s/ and /lit/ portions of the English word "slit" (/slit/), adult listeners typically hear the word as "split" (/split/). 2 experiments were conducted to investigate the ability of 6-8-month-old infants to discriminate brief periods of interconsonantal silence in "slit" versus "split" contrasts. Infants were tested in multiple sessions, using a conditioned head-turning paradigm. 3 sets of stimuli were employed: /slIt/, /slIt/ +Silence, and /splIt/, containing 0, 173, and 90 msec, respectively, of silence duration following the /s/ portion of the stimulus. In both experiments, infants reliably discriminated /slIt/ +Silence from the /slIt/ stimuli but not from the /splIt/ stimuli. Therefore, it appears that infants, like adults, do not treat stimuli containing 90 or 173 msec of silence in this interconsonantal context as different.

Conditioning, Operant↗
PubMed1981

Vagueness and empathy: a Jamesian view.

Three types of thought about the world are put forth by James in Pragmatism: common sense, science, and philosophy. The worlds of science and philosophy reified and idealized aspects of the vague, intersubjective world of common sense. However, once "formed" these two worlds are themselves "formative." They can and have infected the vague world of common sense with a quest for certainty and immediacy. Empathy arises as a problem through the conceptual world views of science and philosophy, insofar as the vague is not acceptable. Using James' views on language and his metaphysics, I argue that empathy appears epistemically as an issue unsolvable in terms of certainty, and empathy appear ontologically as an issue which compels action. In medicine, empathy exists as a problem because pure consciousness has come upon the scene as a "rip" or "tear," in Sartrean terminology. The physician finds himself "encrusted twice over"; consciousness has arisen and also professional consciousness has arisen. He/she works back, not simply toward the world of common sense, now infected, but toward the pre-reflective world. Such a recovery is never complete, yet such a recovery must always be attempted.

Affect↗
PubMed1981

Discrimination of voice onset time in infancy.

In an effort to determine whether infants can discriminate speech sounds on the basis of a single acoustic cue, timing onset of periodic voicing, two experiments were conducted employing synthetic speech sounds. Naturally produced syllable pairs were also used for comparison. In the first experiment infants evidenced discrimination of a naturally produced /ba/ versus /pa/ pair and a naturally /du/ versus /tu/ pair. In addition, infants discriminated a synthetic /ba/ versus /pa/ contrast that was cued by several acoustic differences in addition to timing onset of periodic voicing but failed to evidence an ability to discriminate a synthetic /du/ versus /tu/ contrast that contained flat first formants and differed only in timing onset of periodic voicing. A second experiment was conducted in which infants once again evidenced discrimination of naturally produced /du/ versus /tu/ stimuli but not of synthetic /du/ versus /tu/ stimuli containing slight first-formant transitions. These results suggest that timing onset of periodic voicing alone may not be a sufficient cue for infant discrimination of English voicing contrasts.

Acoustic Stimulation↗
PubMed1980

Hexamethonium modification of cardiovascular adjustments during combined static-dynamic arm exercise in monkeys.

In weight lifting and rowing, essentially the same groups of muscles contract in isometric (static) and isotonic (dynamic) fashion. To approximate the combined static-dynamic arm movements involved in rowing or lifting weights, four rhesus monkeys were trained to pull a T-bar and thereby avoid tail shock. Each animal received 8 daily test sessions in which loads (0.4, 0.8, 1.2, 1.6 kg), total pulls (3, 6, 9, 12 at a constant pull frequency, 0.5 Hz) and alternate sessions of pulling after injection of hexamethonium chloride (7 mg/kg) or saline were factorially combined. Our data indicate that heart rate in this model is primarily influenced by the duration of the dynamic exercise component (number of pulls) in this specific exercise task whereas both dynamic and static components affect systolic and diastolic blood pressure. After ganglionic blockade, heart rate and diastolic pressure do not change appreciably during T-bar pulling while the rise in systolic pressure is attenuated and varies primarily as a function of the static exercise component. The clinical implications of these experiments are discussed.

Animals↗
PubMed1980

Tactual speech perception by minimally trained deaf subjects.

Research on tactual perception of speech has shown that many phonetic contrasts can be transmitted to the deaf through artificial hearing devices that stimulate the sense of touch. Past research has emphasized long-term training with tactual reception for the achievement of maximal perceptual performance. The present study demonstrates that, with a brief training period, deaf adolescents can attain a high level of perceptual performance with a tactual speech system in discrimination of certain hard-to-lipread word pairs pronounced by both a male and female speaker. Thus some speech sounds previously indistinguishable by the deaf people can be immediately available for speech comprehension through the tactual vocoder; and other speech sounds will be recognized with further training. The reason that some contrasts are learned quickly and others require extensive training may be found in a pattern perception postulate proposed by Gavin (1979): word patterns that result in stimulation across a greater area of skin tend to be more discriminable than word patterns which stimulate only small areas of the skin.

Adolescent↗
PubMed1980

Effects of early linguistic experience on speech discrimination by infants: a reply.

This paper is a reply to a critique of Eilers, Gavin, and Wilson (1979) by Aslin and Pisoni (this issue). The reply argues that the critics' contentions are basically unwarranted on both methodological and conceptual grounds. The critique is largely based on misunderstandings of the study's purposes and procedures.

Discrimination Learning↗
PubMed1977

Differential cardiovascular changes as a function of stimulation electrode site in rabbit hypothalamus.

Twenty chronically prepared, unanesthetized rabbits received both high-frequency (200 pulse/sec), short pulse-train (1.0 sec) and relatively low-frequency (25 pulse-sec), long pulse-train (10 sec) electrical stimulation of the hypothalamus. High-frequency, short pulse-train stimulation elicited a pressor response and bradycardia at all 27 electrode sites. In contrast, three other cardiovascular response patterns were obtained following low-frequency, long pulse-train stimulation. These latter patterns reflected a medial-lateral organization of autonomic function within the hypothalamus. Whereas all 15 lateral hypothalamic placements yielded depressor responses, 7 of 12 medial hypothalamic placements yielded pressor responses and tachycardia. Cardiovascular changes following administration of selective autonomic blocking agents (e.g., phentolamine, propranolol, methylatropine) suggest that high-frequency, short pulse-train stimulation elicited a pressor response followed by a reflexive bradycardia essentially mediated by an increase in vagal restraint. In contrast, the heart rate changes observed to low-frequency, long pulse-train stimulation all appear to have been importantly influenced by changes at the heart in beta-adrenergic activity.

Animals↗