David Freides

Investigating thought disorder in schizophrenia with the lexical decision task

Prior work has found evidence of hyperpriming in schizophrenics, which has been related to a persistence of associational activation in thought disorder. We extended this work by administering a lateralized version of the lexical decision task to 10 thought-disordered schizophrenics (TD), 10 non-thought-disordered schizophrenics (NTD), and 11 control subjects to localize the patterns of priming. All subjects were right-handed males. Associated, unassociated, and neutral prime-target pairs were displayed across seven stimulus location combinations: prime and target both presented to the center, left visual field (LVF), or right visual field (RVF); prime presented to the center with target presented to the LVF or RVF; and prime and target presented contralaterally. TD schizophrenics exhibited priming effects comparable to those of the other subject groups, suggesting intact semantic memory structures and memory processes that may be unimpaired under the conditions studied. It is believed that the associative process mediating priming effects found in schizophrenia are later in the sequence than those examined in this study.

Temporal Lobe Epilepsy and Performance on the Wisconsin Card Sorting Test

The replicability of previous evidence for differential performance between left and right temporal lobe epileptic patients on the Wisconsin Card Sorting Test (WCST) was evaluated in a new sample of candidates for focal resection. Many subjects obtained high scores on indices of perseveration, which are commonly thought to reflect frontal dysfunction, but there were no differences in performance between patients with language-dominant and nondominant temporal foci. The findings confirm existing evidence that performance decrements on the WCST can be associated with epileptic foci and focal lesions in nonfrontal brain lesions.

Do dichotic listening procedures measure lateralization of information processing or retrieval strategy

The data from two dichotic studies, both of which evaluated spontaneously generated response strategies under free recall and one of which also manipulated retrieval strategy by instruction, supported a conception that what dichotic procedures mostly measure are response strategies—mobile and readily deployed without loss of mnemonic capability. Consequently, competitional methods which are heavily influenced by output factors appear to be unreliable as a means of evaluating input processing dominance.

On the independence of physical and nominal codes: a correlational analysis

In studies of college students, normal children at three grades, and learning-disabled children, physical and nominal matching procedures were highly correlated, (range .72-.96). In each instance, expected time differences favoring physical matches were replicated. Comparable results were found with both tachistoscopic and paper-and-pencil methods. In two studies where relevant data were available, correlations were not significantly attenuated when the effects of motor speed were partialled out. The results challenge the premise that nominal and physical matching measures are empirically independent, invalidate their application as measures of independent types of information processing, and help explain inconsistent findings in hemispheric specialization research.

Regarding the database for the Peniston alpha-theta EEG biofeedback protocol.

Five papers by Peniston and colleagues, which constitute the basic literature for alpha-theta EEG biofeedback treatment for alcoholism and posttraumatic stress disorder, are reviewed. As a result, we raise three questions: (a) Are the samples studied independent? (b) What was the clinical status of the participants prior to treatment? (c) What treatment did the participants actually receive? In seeking answers to these questions we aim to strengthen the database for neurofeedback with specific procedural information so that claims of efficacy can be tested and accepted or rejected on an objective basis.

Note on scoring perseveration on the Wisconsin card sorting test

Abstract Considerable confusion exists regarding the scoring rules of the Wisconsin Card Sorting Test. The purpose of this brief communication is to provide a supplement to the rules for scoring perseveration found in the Wisconsin Card Sorting Test manual (Heaton, 1981). These rules are to be used in conjunction with the manual, and are intended to clarify the existing rules, without modifying them or adding new rules.

Proposed standard of professional practice: Neuropsychological reports display all quantitative data

It is proposed that the standard for the profession be that neuropsychological reports include a display of all quantitative findings. Arguments in favor of the proposal are presented.

Narrative and visual spatial recall: Assessment incorporating learning and delayed retention

Abstract We determined whether memory for a complex figure improves (learning occurs) after re-presentation of the stimulus despite a delay, as it does for verbal narrative information in the Babcock-Levy recall procedure. In addition, we compared interdigitated administrations of the verbal and nonverbal tests, which reduce delays to 5 minutes, to separate administrations of each test with delays of 20 minutes. Scoring manuals were written, and interscorer reliabilities in the .90s were obtained. Results indicated that visual-spatial recall improves, that the two delays generated equivalent results and that these measures of visual-spatial and verbal memory are not correlated. The interdigitated sequence may be an efficient battery for measuring deliberate recall and learning of verbal and nonverbal complex information.

On determining footedness.

The limitations of the most commonly used procedure for determining foot dominance are pointed out and alternatives are suggested.

Blind Evaluation of Body Reflexes and Motor Skills in Learning Disability.

Motor dysfunctions have been associated with learning disabilities in casual observation and systematic study. However, most prior work has concentrated solely on high-level skills and has been subject to observer bias. In this study, boys with learning disability were blindly compared with paired controls on measures of postural and equilibrium reflexes as well as skills. Learning-disabled children as a group showed significant deficits on all measures; a few, however, were totally without deficit. The implications of these findings for controversies about the role of motor dysfunction in learning disabilities are examined.