Is Speech Arrest during Wada Testing a Valid Method for Determining Hemispheric Representation of Language?

Background and objective: The intracarotid amobarbital procedure, or Wada test, is the method of choice to determine hemispheric representation of language, and is routinely used in the presurgical evaluation for intractable epilepsy. Some investigators perform comprehensive language assessments, but others base language lateralization solely on speech arrest. This study sought to determine whether speech arrest alone during Wada testing provides valid data regarding language lateralization. Methods: The subjects (previously reported) were 21 patients evaluated for intractable epilepsy, who underwent language lateralization by Wada testing and functional MRI (FMRI). For each patient, language representation was determined by calculating: (1) a Wada laterality index based exclusively on speech arrest; (2) a Wada laterality index based on comprehensive language assessment; and (3) an FMRI laterality quotient. Correlation coefficients and categorical classifications were analyzed. Results: There was no significant correlation between the Wada laterality quotient derived from duration of speech arrest and either the comprehensive Wada language laterality score (r= .35,p= .12) or FMRI language laterality score (r= .32,p= .16). Categorical classification as left, right or bilateral language also showed marked discordance between speech arrest and the other two methods. Conclusion: Duration of speech arrest during Wada testing is not a valid measure of language dominance.     

A critical review of theS/L reliability index

The meaning and properties of a commonly used index of reliability, S/L,were examined critically. It was found that the index does not reflect any conventional concept of reliability. When used for an identical behavioral observation session, it is not statistically correlated with other reliability indices. Within an observation session, the standardizing measure of Lis beyond the control of the investigator. Furthermore, the reason for the choice of Las the standard is unclear. The role of chance agreement in S/Lis not known. The exact interpretation of the index depends on which observer reports L.Overall the conceptual and mathematical meaning of S/Lis dubious. It is suggested that the S/Lindex should not be used until its nature is shown to be a measure of reliability. Other approaches such as the intraclass correlations and generalizability coefficients should be used instead.The authors are indebted to Johnny Matson for his critique of an earlier version of this paper.     

Effects of component length and of the transitions among components in multiple schedules

Pigeons received equal variable-interval reinforcement during presentations of two line-orientation stimuli while five other orientations appeared in extinction. Component duration was 30 seconds for all orientations and the sequence was arranged so that each orientation preceded itself and each other orientation equally often. The duration of one component (0°) was shortened to 10 seconds and the other (90°) was lengthened to 50 seconds. All animals showed large increases in response rate in the shortened component and this increase was recoverable after an interpolated condition in which all components were again 30 seconds in duration. This effect was replicated in a second experiment in which component duration was changed from 150 seconds to 50 seconds and 250 seconds. An examination of local contrast effects during the first experiment showed that the shortened component produced local contrast during subsequent presentations of the lengthened component, just as would a component associated with more frequent reinforcement. When the presentation sequence was changed so that the lengthened component was always followed by the shortened component, response rates generally increased during the lengthened component. When the sequence was arranged so that the shortened component always preceded the longer component, response rate decreased in the former. These effects, as well as the increases in response rate following change in component length, seem not to be the product of local contrast effects among components.     

Children's responses to stories with male and female characters

The sex of the main character was varied in six children's stories which were then read by fourth, sixth and eighth graders. The children answered four questions about the stories. Both boys and girls responded more positively to the questions “Would you like to be (character's name?)” and “Would you like to do the things (character's name) did?” when the main character was a male. Boys preferred stories about males, and this preference increased with grade level. A preference for stories about females was marginally significant only for the older girls. Theoretical and practical implications are discussed.     

Local contrast and maintained generalization.

Pigeons received variable-interval reinforcement for key pecking during presentations of horizontal and vertical line-orientation stimuli, while pecks during five intermediate orientations were extinguished. Lowest peck rates were observed during presentations of negative stimuli adjacent to the positive orientations while peck rate during 45 degrees (the intermediate negative orientation) was relatively high, i.e., there were negative contrast shoulders. When peck rates were manipulated in the positive orientations, peck rate in neithboring orientations changed in the opposite direction. Contrast shoulders faded after prolonged training. A second type of contrast, local contrast, was correlated with similarity of preceding stimulus and different average peck rates during different stages of the discrimination process. The data suggest that sequential local contrast accompanying the formation of a discrimination contributes to the form of generalization gradients. Blough's model of stimulus control predicts the changes in gradient form described here, but may not accurately depict the underlying process responsible for gradient form.     

Extending Holland's theory to the later years

Sixty-five men and women, aged 50 to 88 years, completed Holland's Vocational Preference Inventory (VPI) and a work history questionnaire. Each participant was assigned one-letter Holland personality type codes for his or her first full-time job, longest full-time job, last job (if retired) or present job (if employed), and hobbies. In general, VPI scale scores and high point codes were consistent with the occupational codes but less consistent with the hobby code. The usefulness of Holland's vocational theory to the aged population is discussed.     

A comparison of techniques to affect sociometric status: A small step toward primary prevention in the classroom?

Interdependent tasks and role play were implemented as treatment conditions in three elementary classrooms (n=142) to affect the peer nominations of the subjects. Third to fifth grade subjects, 68 female and 74 male, received $\text{1}\text{2}$ hour per day of treatment or a control condition for two weeks. Sociometric measurements were obtained prior to the treatment, one week after, and six weeks after. Analysis of covariance was used to test the effectiveness of the treatments. One week following treatment, intersependent tasks was effective (p<.05) in causing subjects in all grades to pick formerly low status children. On the six weeks followup only fifth grade subjects showed the effects of interdependent tasks (p<.01). Several post hoc analyses were performed to investigate the mechanisms behind the change. The results suggest that interdependent tasks may be an effective strategy in raising the popularity of low status children if the treatment becomes an ongoing part of classroom routine. The implications for primary prevention are discussed.