Effects of right hemisphere damage in an adult stutterer

One thesis on stuttering states that stuttering results from hemispheric imbalance of language. Some authors have reported stutterers who ceased stuttering following unilateral neurosurgical procedures, thereby correcting this imbalance. The first case of a stutterer in whom a right hemisphere stroke subsequently developed is reported here. The effects of the stroke on his speech production are discussed.     

Stuttering onset after laryngectomy

Two cases of onset of stuttering subsequent to laryngectomy are reported. These patients demonstrate that the existence of a larynx is not necessary for the generation of stuttering. The findings support the hypothesis that neuromotor control of sound source (laryngeal or alaryngeal) plays a critical role in the generation of stuttering-type dysfluencies and, perhaps, even in the onset of stuttering. They also suggest that dramatic alteration in sound source has the potential for dramatically altering fluency.     

Dementia in Parkinson disease: A neuropsychological analysis

An extensive set of neuropsychological measures was administered to 60 Parkinson's disease patients and age-, sex-, and education-matched controls in order to investigate the nature and prevalence of the cognitive deficit in the disease. Parkinsonian patients performed significantly poorer on all measures with the exception of tests for apraxia and object recognition, and on a test of vocabulary knowledge. Discriminant analysis of the test data revealed that over 93% of patients are impaired relative to matched controls, but that assigning a prevalence rate for dementia in the disease may be difficult due to the continuous distribution of cognitive deficits.     

Spatial ability and handedness

The relationship between preferred handedness and spatial visualization was examined for 124 female and 229 male undergraduate students. Handedness and spatial ability were used in the design as continuous variables. Other variables examined were sex of subject and family history of sinistrality. Spatial ability was found to be systematically related to measured handedness, familial left-handedness, and sex of subject. Males outperformed females at all levels of handedness. The lowest performance was obtained by subjects who were either extremely left-handed or extremely right-handed. The highest scores were obtained by individuals with left-handed relatives and whose handedness scores were in the range considered mixed or slightly right-handed. The results suggest that decreased hemispheric specialization is associated with increased spatial ability.     

The usefulness of distinguishing between a defensive and a nondefensive external locus of control

The study's purpose was to determine whether a distinction can be made between individuals adopting an external locus of control as a defense and those adopting the orientation because it reflects their life experience. It was hypothesized that the two groups differ in the amount of personal responsibility they accept for task outcomes. Internals and externals were identified and then further designated as high or low in action taking. Among externals, a high action-taking score implied defensiveness. Subjects randomly received either success or failure feedback on a presumed task of interpersonal sensitivity. Defensive externals varied their causal attributions as a function of outcome, whereas nondefensive externals did not (p < .05). The distinction between defensive and nondefensive external control was thus supported.     

Defensive burying of aversive fluids in rats: The effects of peripheral anosmia

Three experiments were conducted in order to determine the role of olfactory stimulation in defensive burying of aversive fluids in rats. The results revealed that zinc sulfate-induced anosmia eliminated burying of fluids paired with lithium chloride as well as an inherently aversive solution. This occurred despite the fact that the rats avoided consuming them. These data indicate that defensive burying of aversive fluids is governed by olfactory stimuli and confirms an earlier report, which indicted that burying does not occur in response to aversive gustatory stimuli.     

Dichotic listening pattern in conduction aphasia

This paper reports a finding of hemispheric brain asymmetry for speech in short-gestation infants (mean gestational age = 36 weeks). Using a new measure—degree of reduction in limb tremors following exposure to speech stimuli compared to two control groups, one hearing orchestral music, the other no patterned stimuli—we found that speech disproportionately affected right limb movements. It is not clear whether the effect is due to asymmetries in cortical or subcortical processing. This provides evidence against the notion that brain specialization for language functions necessarily appears over time; rather, specialization for some functions (e.g., speech reception) must be present at birth.     

An assessment of cerebral dominance in language-disordered children via a time-sharing paradigm

A time-sharing paradigm was used to assess language lateralization in language-disordered and normal children aged 4–7 years. Several expressive language tasks as well as a vocal, but nonlinguistic, task were administered concurrently with unimanual finger tapping. Dependent variables were percent disruption scores and number of syllables produced per concurrent trial. All language concurrent tasks produced tapping reductions for both hands for both groups. This result contrasts to similar time-sharing studies claiming asymmetrical interference and hence language lateralization in children (N. White & M. Kinsbourne, 1980, Brain and Language, 10, 215–223; J. Obrzut, G. Hynd, A. Obrzut, & J. Leitgeb, 1980, Brain and Language, 11, 181–194). A multiple regression analysis revealed a significant interaction effect differentiating language-disordered from normal children. Normals exhibited a parallel response pattern for speech and tapping (both increased or decreased in rate) under all lateralization conditions. Language-disordered children exhibited an inverse response pattern (e.g., if speech output increased, tapping rate decreased) only under left-hemisphere time-sharing.     

Spatial localization in children after changes in position

Five experiments investigated the young child's ability to retrieve a target after a change in the position of the child or the target. In Experiments I–IV 2- to 4-year-old children were rotated 90, 180, 270, or 360° about a stationary square table containing four identical hiding locations at each of the cardinal locations. The children tested performed this task significantly better than chance, but their errors reflected either their response biases in the absence of any information as to the location of the target, or the repetition of a response which had been successful in retrieving the target prior to the change in position. When the children were forced to respond rapidly, these errors increased significantly. In Experiment V a table top was rotated 90, 180, 270, or 360° in front of 3- to 10-year-old children. There were two cue situations. The child saw the rotation, or the child had to infer the rotation. Young children made errors of the types observed in Experiments I–IV. The ability to inhibit these errors increased with age. By 7 years of age performance was virtually perfect when the child could observe the change in position of the hidden object. The ability to infer the positional change developed more slowly and was good but not perfect at 10 years of age.     

The noninvasive measurement of regional cerebral circulation

A brief introduction to the history and development of the noninvasive regional cerebral blood flow technique is presented. The procedures and apparatus are described in a nontechnical manner to provide a resource background for the other papers in this issue.     

Dominance as a function of cue similarity: A test of the intrinsic cue dominance model

A nonselective model postulating intrinsic cue dominance was tested in simultaneous discrimination tasks involving reversal on one dimension. In this procedure two dimensions are relevant throughout training; however, following initial discrimination training the reward contingency is reversed for one dimension but maintained for the other. Cue dominance was assessed following acquisition of reversal by the use of opposed-cues test trials, and was defined as a greater number of choices of the test compound containing the positive cue of the reversed dimension than of the test compound containing the positive cue of the maintained dimension. In Experiment I, brightness cues dominated orientation cues. In Experiment II, which employed two different sets of relevant cues, more disparate brightness cues dominated the orientation cues for one set and orientation cues dominated less disparate brightness cues for the other. From this, it was concluded that dominance is a function of relative cue similarity.     

Developmental differences in cognitive mapping: Configurational knowledge of familiar large-scale environments

In order to investigate the development of cognitive mapping of familiar large-scale environments. First-, fifth-, and eighth-grade children were asked to make bearing and distance estimates to six targets from three sighting locations in their school. Correlations between estimated and actual bearings and distances were extremely high at all grade levels, indicating that (a) children at all grade levels could reliably make such estimates, and (b) route knowledge of even the youngest children was quite high. Bearing accuracy increased between first- and fifth-grade and showed little improvement thereafter. Increases in a measure of configurational accuracy were found between first- and fifth-grade and between fifth- and eighth-grade. Differential accuracy as a function of the demands of particular sighting locations was found only for the younger children.     

Taste-mediated potentiation of noningestional stimuli in rats

Holtzman rats drank saccharin in a distinctive environmental chamber prior to lithium-induced toxicosis. This treatment was administered four times. These animals subsequently drank less water or familiar saline in the chamber than animals which received water in the environment during conditioning. In addition, these environmental stimuli blocked the formation of a lithium-mediated coffee aversion more if they were conditioned in the presence of saccharin than if they were conditioned in the presence of water. Such differential blocking provided further evidence that the presence of a taste during conditioning facilitated aversion learning to the environmental chamber.     

Semantic integration: Effects of imagery,enaction, and sentence repetition training on prereaders' recall for pictograph sentences

This study examines the effectiveness of an integrative imagery strategy in contrast to more concrete enaction and repetition strategies for improving kindergarten children's recall of pictograph sentences. The training groups were taught in two brief sessions to read the pictograph sequences as sentences and then to imagine the sentence's action (sentence imagery), act out the sentence using toys (sentence enaction), or repeat each sentence twice (sentence repetition). After training, the enaction group significantly outperformed the imagery and sentence repetition groups, which outperformed a repetition control group. Two weeks later, the imagery and enaction groups no longer differed significantly in recall and both groups significantly outperformed the repetition control group. The imagery group alone significantly outperformed the repetition control group on a no-toys generalization test. Implications of the results concerning strategy training of young children, the effectiveness of imagery strategies, and experimental design are discussed.     

Origin of the speech apparatus and its reconstruction in fossils.

Renewed enthusiasm has produced provocative speculations in recent literature on the origin of speech. The purpose of the present investigation is to expose the adaptive renovations underlying the emergence of a “Vocal Tract” and from this to define its anatomical substrate which governs the biomechanics of speech production. The vocal tract is a double resonator tube coupled in series and composed of oral and pharyngeal cavities. Analysis is made of the crucial structural elements of this complex from detailed dissections in modern man and the study of modern and fossil hominid crania. The study focuses on relations of the skull base, jaw, hyoid bone and the contained tongue, pharynx and valvular devices, calling into question recent reconstructions built on classical Neanderthal skulls.     

Positive and negative conditioned suppression in the pigeon: Effects of the locus and modality of the CS

In Experiment I, four pigeons were exposed to trials in which a 12-sec key light illumination was followed by free food. These trials were superimposed upon a baseline of key pecking for food reinforcement on a variable-interval schedule. When the signal for food was on the operant key, response rate was substantially higher during the signal than during the baseline procedure. When the signal was on a second, signal key, operant responding was suppressed during the signal and substantial pecking of the signal key occurred. The sum of signal key and operant key pecks far exceeded the operant baseline rate of responding. An explanation of opposite results obtained with rats and pigeons as subjects in experiments of this type was suggested in terms of the spatial relation between the signal for free food and the operant target which usually characterizes these experiments. Experiment II assessed the importance of signal location when shock rather than food was the US. Suppression of operant key pecking was unaffected by signal location. Experiment III assessed the relative effectiveness of visual and auditory stimuli (clicks) as signals for food and shock, and found that all combinations of signal and US were equally effective in suppressing operant key responding. The three experiments together suggested that the identification of important effects of species—typical behavior in one experimental situation does not imply that there will be like effects in similar situations.