Syntactic determinants of stuttering in the spontaneous speech of normally fluent and stuttering children

Conflicting findings have been reported concerning whether fluent children use more complex syntactic structures than stutterers and whether or not stutterers experience specific difficulty with complex syntactic structures. On critical examination, the first of these apparent discrepancies appears to be due to (a) differences in the methods employed for syntactic analysis in different studies, and (b) misleading impressions gained by looking at speakers within a single age range. Data were reanalyzed where one method of analysis had shown that fluent speakers and stutterers did not differ with regard to syntactic structures used but where they did show a propensity for stuttering to occur on complex syntactic structures. These data cover a range of age groups. When the second method of syntactic analysis was applied, a difference was found between fluent speakers and stutterers, with the stutterers initially using more simple structures and fewer complex ones. This difference decreased over age groups. However, a difference still remained with respect to which syntactic structures stutterers experience difficulty. An additional analysis, not formerly conducted on these data, showed that, as reported elsewhere, there was a higher probability of stuttering on clause-initial and. It was also shown that this tendency decreased with age group of the stutterers.     

Communicative behavior of mothers of stuttering and nonstuttering high-risk children prior to the onset of stuttering

This portion of a multiyear prospective study was designed to investigate the communicative style, speaking rate, and language complexity of 93 mothers of preschool children with a parental history of stuttering. At the initial session none of the children sampled was regarded as being a stutterer. One year later, 26 of the children were classified as stutterers. Statistical analyses revealed that prior to the onset of stuttering the mothers of these children did not differ from the mothers of the children who continued to be seen as nonstutterers with respect to either communicative style or speaking rate. The only significant difference between the two groups of mothers was the complexity of their language. The pre-onset mean lengths of utterance (MLUs) of the mothers of children who later came to be regarded as stutterers were significantly shorter than those of the mothers whose children continued to be viewed as being fluent. These findings suggest that the communicative behavior of mothers of normally fluent children do not contribute to the development of stuttering.     

The temporal selectivity of additive factor effects on the reaction process revealed in ERP component latencies

An experiment was conducted to relate individual components of the event-related brain potential to specific stages of information processing in a two-choice reaction time (RT) task in a group of undergraduate students. Specifically, the latency of the P300 component and the lateralized readiness potential (LRP) were studied as a function of variations in stimulus degradation and response complexity. It was hypothesized that degrading the stimulus would delay the P300 and LRP to the same extent as RT, and that increasing response complexity would affect RT but not P300 latency. The extant literature did not permit any hypothesis regarding the effect of response complexity on LRP latency. The two task variables were found to have additive effects on RT. As predicted, variations in stimulus degradation influenced the latencies of both components, whereas alterations in response complexity had no effect on P300 latency. A significant new finding was that the onset latency of the LRP remained unchanged across levels of response complexity. The overall pattern of results supports the notion of temporal selectivity of stage manipulations that is derived from discrete stage models of human information processing. Furthermore, these results refine the functional interpretation of the LRP by indicating that within the conceptual framework of a stage model the processes this component indexes succeed the start of response choice but precede the start of motor programming.     

The WISC-III: A reality check

Although the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) is arguably the best instrument currently available for assessing students' intelligence, its use will present practitioners, especially school psychologists, with some unique challenges. Recent research suggests that significant reductions in special education students' WISC-III Verbal, Performance, and Full Scale IQ scores will be found, compared with their previous WISC-R results. This finding will have a profound impact on special education placement decisions. Specifically, students who were previously found eligible for learning disability programs may now no longer evidence the significant discrepancies necessary in order to receive continued services. Conversely, students earlier identified as “slow learners” may now be eligible to receive services for those classified under the category of educably mentally handicapped. In addition, the notion that the WISC-III may underestimate the ability of certain populations of students requires further exploration. This article will address these issues as well as implications for practitioners presently administering the WISC-III.     

Sparing and recovery of function in spinal larval frogs (Rana catesbeiana): effect of level of transection.

Bullfrog tadpoles with cervical or midthoracic transection of the spinal cord were allowed to recover for 5 weeks, at which time axonal growth across the transection site was assessed by transport of horseradish peroxidase. Weekly behavioral tests included those for posture, spontaneous locomotion, cutaneously elicited swimming, and intersegmental coordination. Behavioral and electrophysiological assessments suggest that behavioral recovery depends, at least in part, on the growth of fibers across the transection site. Anatomical and behavioral recovery does not appear to differ with the level of spinal transection, but there was greater sparing of posture, spontaneous locomotion, and stimulus-induced locomotion in tadpoles with thoracic transection of the spinal cords.