Assessment of the relative importance of S+ and S− in rats using differential training on intercurrent discriminations

The present studies assessed the degree of stimulus control exerted by S+ and S? without confoundings of stimulus novelty and stimulus ambiguity. In Experiment 1, rats were trained on two intercurrent simultaneous discrimination problems with nine times more training given on one than the other. Then the animals were given transfer tests with re-paired stimuli. The results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination. Experiment 2 provided a test of the possibility that the relative degree of control by S? varies with different amounts of training. Three groups were trained on two intercurrent simultaneous discrimination problems; each group was given 7, 11, or 15 times more training on one problem than the other. Then transfer tests were given with re-paired stimuli. Again the results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination.     

Shift of visual field preference for Hebrew words in native speakers learning to read

Lateralization for Hebrew words was tested in both the visual and auditory modalities in Israeli children learning to read their native language, Hebrew. A left visual field preference for tachistoscopically presented words was found in the second graders in contrast to a right visual field preference for the same words in the third graders. Children in both grades showed a right ear dominance for similar words presented dichotically. These data suggest right hemisphere involvement in acquiring reading skills of a native language.     

Auditory processing of brain-damaged adults under competitive listening conditions

Right CVAs, mild left CVAs, and non-brain-damaged adults received the Token Test under three conditions: quiet, white noise, and speech babble. Left CVAs performed most poorly of all groups in all conditions experiencing difficulty with subtests III, IV, and V. Right CVAs were inferior to controls on each of these three subtests in the speech babble condition only. Thus, right CVA difficulty with both memory and syntactic tasks was demonstrated in speech babble. These results are explained by the hypothesis that both hemispheres are necessary to process auditory information under complex listening conditions. Total brain capacity of right CVA patients may be overloaded if either memory load or linguistic complexity is increased in the presence of certain types of listening competition.     

Retention of verbal information by rehearsal in relation to the fluency of verbal output in aphasia

The purpose of the present study was to determine if aphasic subject groups differentiated by the fluency of their verbal output employed rehearsal as a strategy for maintaining verbally coded information in primary memory. A task based upon the Brown-Peterson paradigm was administered to 10 fluent aphasic patients, 10 nonfluent aphasic patients, 10 right-brain-damaged patients, and 10 nonneurological patients. The findings indicate that the nonfluent aphasic patients did not rehearse the verbal information while the fluent aphasic, right-brain-damaged, and nonneurological patients did rehearse. In addition, both fluent and nonfluent aphasic patients encoded significantly less information into the memory system initially and performed worse on the task overall than right-brain-damaged and nonneurological patients.     

Contrasting cases of Italian agrammatic aphasia without comprehension disorder

This study examined the effects of different concurrent verbal memory loads on a recognition accuracy task using bilaterally presented nouns. Four different memory load conditions were examined. They varied along a size dimension of either three or six words and along a complexity dimension of either easy concrete nouns or difficult highly abstract nouns. In each of the above conditions and in one control group, order or word report was controlled and in a second control group subjects were free to report the lateralized words in any order they wished. There were 20 subjects in each of the six groups. As expected, a significant right visual field superiority for verbal processing was obtained. there were no main effects of size of memory load nor complexity of m emory load on the laterality patterns. More subtle fluctuations in the patterns were found in the form of significant interactions between memory load, order of word report, and visual field. These interaction effects suggest that words reported second in the bilateral task, are more susceptible to the interfering effects of either larger or more complex memory loads. This is particularly true for right visual field words. While these data generally support a structural model of hemispheric organization, the interaction effects suggest that modifications must be made to the basic model to account for such factors as hemispheric capacity limits and order of report in the bilateral task.     

An awareness approach to the covert symptoms of stuttering

Speech-language clinicians working with the confirmed stuttering client are often faced with the clinical management of the covert symptoms of stuttering in addition to the more observable and measurable overt symptoms. The authors report the successful use of awareness techniques to exaggerate the subjective experience of these covert symptoms and encourage the use of these techniques as an adjunct to the counseling and desensitization procedures traditionally employed. A transcribed clinical management session in which several awareness techniques are used to aid the client in an introspective examination of “anticipation of stuttering,” is analyzed in order to reach some specific recommendations for using awareness techniques in the clinical management of the covert symptoms of stuttering.     

Further study of the electrophysiological correlates of lexical decision

Discriminations were required between words, pseudohomophones, and visually matched nonwords. Two tasks were employed, one which could be accomplished on the basis of a visual code (the REAL task, involving discrimination between words and both types of nonword) and another necessitating the use of a phonological code (the REAL/PSEUD task, words and pseudohomophones vs. nonwords). ERPs were recorded from three midline sites and from left and right inferior parietal sites. Two principal results were observed, (i) the peak latency of a late positive component, P637, covaried with RT, with variations in latency of around one half the corresponding RT variations, and (ii) the peak-to-peak amplitude of N100-P187 interacted with stimulus and task, such that it was larger for nonwords in the REAL task and words in the REAL/PSEUD task. No taskor stimulus-dependent asymmetries were observed in any ERP component. The P637 latency data support a model of RT variation based on the interaction of changes in parallel response preparation and stimulus evaluation processes. The observations with respect to N100-P187 suggest that ERPs are sensitive to factors related to the early processing of words and word-like visual material.     

The use of the psychological stress evaluator with stutterers

A lie detection instrument, the Psychological Stress Evaluator, has been reported by the manufacturer as being capable of quantifying changes in the degree of “stress” as reflected by a subject's voice. Speech pathologists might consider the use of the instrument in clinical and research activities concerning the stutterer's emotional (stress) reaction to stuttering.To test the validity of the instrument, four stutterers and four normal speakers were recorded while making consecutive telephone calls. Randomized recordings were analyzed by a company trained technical to determine the degree of stress for each speech sample.Results indicated that both groups had a significant reduction of stress from the first to the fourth telephone call. However, the groups did not differ in the degree of stress during the ordered series of calls. Due to the inability of the Psychological Stress Evaluator to differentiate between the groups, the validity of the instruments is questioned.