Early lexical development in children with focal brain injury

Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.     

Adult age differences in letter-level and word-level processing

Older and young adults' letter detection and lexical decision performance were examined as word frequency varied to determine whether there were age differences in word recognition. Allen and Madden (1989) found that older adults' pattern of reaction time (RT) across word frequency categories was different from young adults' pattern for a letter detection task. In this study, for both letter detection and lexical decision tasks, older adults exhibited a monotonically decreasing RT function as word frequency increased. However, young adults exhibited a nonmonotonic RT function across word frequency for the letter detection task but a monotonically decreasing RT function as word frequency increased for the lexical decision task. An expanded parallel input serial analysis model of word processing was hypothesized.     

RITALIN VS. RESPONSE COST IN THE CONTROL OF HYPERACTIVE CHILDREN: A WITHIN-SUBJECT COMPARISON

A within-subject comparison was made of the effects of methylphenidate (Ritalin) and response cost in reducing the off-task behavior of two boys, 7 and 8 years of age, who had been diagnosed as having an attentional deficit disorder with hyperactivity. Several dosages of Ritalin (5 to 20 mg/day) were evaluated with the results indicating varying effects of the drug for both children. Response cost (with free-time as the reinforcer) was superior to Ritalin in raising levels of on-task behavior and in improving academic performance.     

Strategies in cross-modality matching

Subjects were tested on cross-and within-modality matching conditions with either a 5-sec or a 20-sec delay imposed between standard and comparison stimuli. Half the subjects were informed before the trial of what the comparison modality would be, while the others were not. There was a strong effect of instructions on the cross-modality conditions, but little on the within-modality conditions. The informed subjects showed better performance in the haptic-visual condition, while for the uninformed subjects, visual-haptic performance was better. The results suggest the importance of subjects’ processing strategies in cross-modality performance.     

Counting eliminates the repetition effect in judgments of temporal duration.

College student subjects estimated the duration of time intervals (8–54 sec) by counting or not (N=35 per group). Counting eliminated the repetition effect (a decline in the magnitude of estimations across trials), and resulted in a truncation of the psychophysical function. The former result was interpreted as contrary to Treisman's (1963) model. The latter result was attributed to the effortfulness of counting, which was established in a subsequent experiment.     

A combined therapeutic approach in a family setting

Combined treatment approaches, co-therapy and family work are three concepts which are under much discussion in psychiatry. This paper describes the systematic use of an integrated treatment approach used by co-therapists working with families in which a child was the referred patient. The rationale behind this approach together with its advantages and disadvantages are discussed. The authors conclude that the approach is sufficiently promising to merit formal evaluation.     

Operant conditioning of epileptic neurons in monkeys and its theoretical application to EEG operant conditioning in humans

This paper reviews a series of previous reports which summarize the physiology of chronic experimental epileptic foci in monkeys. It is shown that such monkeys can be trained to bidirectionally control the firing rates of normal and epileptic neurons which comprise the epileptic focus. As a result of this acquired operant performance, the monkeys show both a decrease in clinical seizures as well as a decrease in single unit epileptic activity. The EEC correlate of this change in single unit epileptic actvity is generalized EEG desynchronization. The conclusion from these data would indicate epileptic neurons can be operantly controlled and this control is not correlated with any specific EEG pattern. This brings to question the specificity of the SMR in EEG biofeedback paradigms which treat human epilepsy. This author feels that the result from such biofeedback studies are the result of the patient learning to manipulate electrical events within the CNS pathways through which the seizure propagates and is not contingent upon specific EEG frequencies.