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Biomedical subjects

S G Zecker

Publications and source records attributed to S G Zecker.

7 recordsLinked to original sources
PubMed1997

Oral sensory discrimination of fluid viscosity.

This study was designed to investigate the ability of normal young adult volunteers to sensorially identify Newtonian fluids of specified viscosities. Twenty subjects, 10 men and 10 women between the ages of 18 and 29 years participated. Seven stimuli, consisting of combinations of corn syrup and water, with viscosities ranging from 2 to 2,240 centipoise (cP) were prepared and characterized using a coaxial rotational viscometer. Subjects were presented with two anchor stimuli representing the extremes of the range of viscosities as a basis from which the experimental stimuli were judged. The seven experimental stimuli were randomly presented to each subject 10 times. The accuracy with which the subjects identified the viscosity of the fluid was significant at p < 0.01. The pattern of response was not significantly different across subjects nor gender. There were no differences in performance throughout the duration of the study. The repeat presentation of the anchor points did not significantly affect performance. Further research on oral perception of viscosity, and the processes that mediate changes in swallow physiology resulting from changes in viscosity is required.

Adult↗
PubMed1996

Auditory neurophysiologic responses and discrimination deficits in children with learning problems.

Children with learning problems often cannot discriminate rapid acoustic changes that occur in speech. In this study of normal children and children with learning problems, impaired behavioral discrimination of a rapid speech change (/dalpha/versus/galpha/) was correlated with diminished magnitude of an electrophysiologic measure that is not dependent on attention or a voluntary response. The ability of children with learning problems to discriminate another rapid speech change (/balpha/versus/walpha/) also was reflected in the neurophysiology. These results indicate that some children's discrimination deficits originate in the auditory pathway before conscious perception and have implications for differential diagnosis and targeted therapeutic strategies for children with learning disabilities and attention disorders.

Adolescent↗
PubMed1991

The go-no go test in attention deficit disorder is sensitive to methylphenidate.

The go-no go test requires a subject to emit a simple motor response to one cue while inhibiting the response in the presence of another cue. This test has been effective in demonstrating impulsivity (elevated commission error rate) in children with attention deficit disorder (ADD). In this study, we examined the effects on go-no go test performance of two doses of methylphenidate (0.15 mg/kg and 0.3 mg/kg) administered in double-blind placebo-controlled fashion to children with ADD. Our results indicate that even modest doses of methylphenidate improve the go-no go performance of these children by decreasing their tendency to make impulsive commission errors. Thus the test is sensitive to the effects of methylphenidate and can be used to monitor a response to therapy.

Adolescent↗
PubMed1990

Visual similarity effects in detecting letter rhymes.

Previous demonstrations of "visual" effects in auditory tasks have been largely restricted to orthographic effects with word stimuli. As a result, explanations of such effects have centered around a shared orthography--the similarity of the spelling patterns at the ends of the words. In the present study, these effects were extended to single-letter stimuli. Subjects made rhyming decisions about pairs of letters presented auditorily. Visually similar letter pairs facilitated responses to rhyming pairs and inhibited responses to nonrhyming pairs. The results indicate that visual effects are not restricted to word stimuli and suggest that additive effects of visual similarity and shared orthography may be responsible for these findings.

Adult↗
PubMed1986

Lateralization of lexical codes in auditory word recognition.

Three experiments examined the lateralization of lexical codes in auditory word recognition. In Experiment 1 a word rhyming with a binaurally presented cue word was detected faster when the cue and target were spelled similarly than when they were spelled differently. This orthography effect was larger when the target was presented to the right ear than when it was presented to the left ear. Experiment 2 replicated the interaction between ear of presentation and orthography effect when the cue and target were spoken in different voices. In Experiment 3, subjects made lexical decisions to pairs of stimuli presented to the left or the right ear. Lexical decision times and the amount of facilitation which obtained when the target stimuli were semantically related words did not differ as a function of ear of presentation. The results suggest that the semantic, phonological, and orthographic codes for a word are represented in each hemisphere; however, orthographic and phonological representations are integrated only in the left hemisphere.

Adult↗
PubMed1984

Subvocal motor activity and contextual processing.

Twenty male and female subjects listened for mispronounced words while minimizing either subvocal or frontalis electromyographic activity. Stimuli were varied on size of the distortion, lexical constraint, and contextual constraint, all known to influence detections. Analysis of both the reaction time and detection data indicated that the minimization of subvocal EMG activity reduced or eliminated the effect of contextual constraint, effect. Results indicate that subvocal activity is related to contextual processing. Additionally, reaction time data are reported that indicate that although low contextual constraint greatly slows the decision process, detectability is actually superior. A possible underlying mechanism for this reversal of the speed-accuracy trade-off is discussed.

Attention↗