Bonnie L. Brookshire

Verbal and nonverbal skill discrepancies in hydrocephalic children

This study evaluated a large sample (N = 90) of 5- to 7-year-old children with hydrocephalus caused by aqueductal stenosis or prematurity-intraventricular hemorrhage or associated with spina bifida. Comparison groups of normal controls, children with spina bifida and no shunt, and premature children with no hydrocephalus were also evaluated. Comparison of skill discrepancies at two occasions separated by 1 year revealed that hydrocephalic children, as a group, showed poorer nonverbal than verbal skills on measures from the McCarthy Scales of Childrens Abilities, the WISC-R, and composites of neuropsychological skills. No discrepancies in verbal-nonverbal memory were found nor were any discrepancies attributable to etiology or motor demands of the tasks. Consistent with current hypotheses concerning the role of the cerebral white matter in cognitive development, these results show that hydrocephalic children in this age range generally have poorer development of nonverbal cognitive skills relative to their language development.

Attentional skills and executive functions in children with early hydrocephalus

Measures of executive functions (Tower of London, Wisconsin Card Sorting Test), focused attention (cancellation tasks), and selective attention (Stroop test) were administered to 116 school‐age children with shunted hydrocephalus, arrested (un‐shunted) hydrocephalus, and no hydrocephalus. The results revealed that children with shunted hydrocephalus solved fewer problems on the Tower of London task and achieved fewer categories on the Wisconsin Card Sorting Test than children with arrested and no hydrocephalus. However, most indices of executive functions derived from these two measures did not significantly differentiate the three groups. Children with shunted hydrocephalus also performed more poorly on the focused and selective attention tasks. However, their poorer performance was related to brain defects influencing motor speed and the transfer of information across the corpus callosum and not to specific effects of hydrocephalus. Children with hydrocephalus do demonstrate problems with attention and ...

Children's narratives following traumatic brain injury: linguistic structure, cohesion, and thematic recall

Narrative discourse and intellectual functioning were examined 3 years following traumatic brain injury (TBI) in children 1 to 8 years of age at the time of injury. The language-impaired TBI group (n = 9) had language deficits during the subacute stage of recovery; their performance was contrasted with that of a TBI comparison group equated on neurologic and demographic variables that did not show subacute language impairment (n = 8) and a sibling comparison group (n = 9). The language-impaired TBI group had lower Verbal and Full-Scale IQ scores and produced fewer words and utterances than the sibling group on a story retelling task; their stories were characterized by fewer complete referential and lexical ties and more referential errors, indicating difficulty conjoining meaning across sentences. The language-impaired TBI group recalled approximately one-third of the propositions needed to maintain the story theme and made more errors sequencing the propositions than either the TBI or the sibling comparison groups. Group differences were not obtained on the Performance IQ scores or on measures of rate or fluency of speech production, mazes, use of conjunctives, or naming errors. The discourse deficiencies of children with TBI and acute language impairment were most pronounced at the level of cognitive organization of the text reflecting text macrostructure and were least apparent at the level of lexical and sentential organization reflecting text microstructure. Results are discussed in terms of the vulnerability of developing language abilities to disruption by brain injury.

Memory Functions in Children With Early Hydrocephalus

Children with arrested, shunted, and no hydrocephalus were compared on verbal and nonverbal memory tasks assessing multiple components of memory. A gradient of severity was hypothesized, with the shunted hydrocephalus group expected to exhibit the most significant memory impairments and the arrested group expected to perform more poorly than children with no hydrocephalus. Etiologies of prematurity, spina bifida, and aqueductal stenosis were represented by 157 participants. Results supported the hypothesis; the shunted hydrocephalus group performed poorer on all memory measures. Differences for the arrested group were less frequently statistically significant relative to children with no hydrocephalus. Irrespective of etiology, the shunted hydrocephalus group exhibited a pattern of performance suggestive of encoding and retrieval deficits on both verbal and nonverbal tasks, showing a pervasive disturbance of memory processes.

Components of Executive Function in Typically Developing and Head-Injured Children

To identify the key components of executive functions (EFs) in children following traumatic brain injury (TBI), data from a series of EF tests administered to 286 pediatric TBI patients at least 3 years postinjury were subjected to an exploratory factor analysis. A 5-factor model included discourse, EFs (e.g., problem solving, planning), processing speed (e.g., coding), declarative memory, and motor speed. Confirmatory factor analysis based on data obtained from 265 pediatric TBI patients at 3 months postinjury disclosed that the 5-factor model provided a good fit to the data. A second exploratory analysis of the 3-month postinjury data disclosed a 4-factor model in which processing speed and motor speed measures loaded on a common factor. Severity of TBI and age at test had significant effects on all factors in both the 5- and 4-factor models. Adaptive functioning, as measured by the Vineland Adaptive Behavioral Scale-Revised, was moderately related to factor scores at 3 years or longer postinjury, but weakly related to factor scores obtained at 3 months postinjury. The factor scores could be used in clinical trials to facilitate data reduction and appear to have validity as indicators of TBI outcome.

Morphometric evaluation of the hydrocephalic brain: relationships with cognitive development

The effects of early hydrocephalus and related brain anomalies on cognitive skills are not well understood. In this study, magnetic resonance scans were obtained from 99 children aged from 6 to 13 years with either shunted hydrocephalus (n=42) or arrested (unshunted) hydrocephalus (n=19), from patient controls with no hydrocephalus (n=23), and from normal, nonpatient controls (n=15). Lateral ventricle volumes and area measurements of the internal capsules and centra semiovale in both hemispheres were obtained from these scans, along with area measurements of the corpus callosum. Results revealed reductions in the size of the corpus callosum in the shunted hydrocephalus group. In addition, lateral ventricle volumes were larger and internal capsule areas were smaller in both hemispheres in children with shunted and arrested hydrocephalus. The centra semiovale measurements did not differentiate the groups. Correlating these measurements with concurrent assessments of verbal and nonverbal cognitive skills, motor abilities, and executive functions revealed robust relationships only between the area of the corpus callosum and nonverbal cognitive skills and motor abilities. These results support the theory of a prominent role for the corpus callosum defects characteristic of many children with shunted hydrocephalus in the spatial cognition deficits commonly observed in these children.

Corpus Callosotomy for Medically Intractable Seizures

To identify factors influencing outcome and morbidity in patients selected for corpus callosotomy, we retrospectively reviewed 23 patients with intractable generalized seizures who underwent corpus callosotomy between 1991 and 1994. Three patients had a complete corpus callosotomy, while 20 had an anterior callosotomy. Three of those patients subsequently had completion of the anterior callosotomy. Overall, 41% of patients were nearly or completely free of the seizure types targeted for surgical treatment, while another 45% had seizures less than half as frequently. Four patients developed simple partial motor seizures after callosotomy. A transient disconnection syndrome was observed in 57% of patients. The best predictor of good outcome was a normal preoperative MRI. Mentally retarded patients had poorer outcomes. Outcome was not predicted by extent of callosal section or lateralization on neurological examination, EEG, MRI, and SPECT. Completion of anterior callosotomy resulted in significant reductions in seizure frequency. Though most patients do not become seizure-free after corpus callosotomy, worthwhile palliation of an otherwise intractable illness can be achieved. An analysis of prognostic factors should lead to better selection of patients for surgery.

Memory Tests Distinguish Between Patients with Focal Temporal and Extratemporal Lobe Epilepsy

We examined the ability of preoperative memory performance to distinguish between patients who had been diagnosed as having left (LTLE, n = 31), right (RTLE, n = 37), and extra‐(ETLE, n = 17) temporal lobe focal epilepsy. All patients eventually underwent surgical resections. Analyses indicated that the ETLE group performed better than the RTLE group on nonverbal memory measures and better than the LTLE group on verbal memory measures. Discriminant function analyses indicated that use of a combination of measures that assess different aspects of memory were of significant value in distinguishing between patients with focal TLE and ETLE. This approach, as compared the use of single measures, improved classification rates of all three groups. The best single predictor of group membership, an index of verbal learning, yielded a 47% overall correct classification rate, with sensitivities ranging from 25 to 59%, and performed at worse than chance levels in classifying RTLE patients. A multivariate approach, which included an index of verbal and nonverbal learning, incidental nonverbal memory, and consolidation of organized and rote verbal material, yielded a 65% correct classification rate, with sensitivities ranging from 57 to 75%. This compares favorably with other noninvasive techniques for lateralizing epileptogenic lesions.

Effects of temporal lobe epilepsy on spatial and figural aspects of memory for a complex geometric figure

The preoperative delayed memory performance on the Rey-Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial seizures of temporal lobe origin was analyzed using 3 different indices. One index (composite) was derived using a common scoring method that included both spatial and figural aspects of memory in its score. The other two indices were derived emphasizing either spatial or figural aspects of memory for the elements of the figure separately. All 3 indices distinguished between individuals with right-sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was significantly lower than figural memory in individuals with RTLE as compared to those with LTLE. Both the spatial and figural memory indices were significantly lower in the presence of magnetic resonance imaging (MRI) evidence for hippocampal sclerosis in individuals with RTLE. Results suggest that while both the spatial and figural aspects of nonverbal memory are sensitive to right hippocampal dysfunction, figural memory may be less vulnerable to the effects of RTLE.

Specific language deficiencies in children with early onset hydrocephalus

Abstract Specific language abilities of children with early onset hydrocephalus were compared to nonhydrocephalic comparison groups. Ninety children, aged 5 to 7 years, composed six subject groups: three groups having a history of hydrocephalus due to spina bifida, prematurity-intraventricular hemorrhage, or aqueductal stenosis. and three comparison groups of children with spina bifida who had never been shunted, premature children with no hydrocephalus, and normal controls. Group performance scores were compared on measures of phonological awareness, semantics, fluency, and word retrieval. Children with hydrocephalus performed below their peers on all measures. These results indicate that early onset hydrocephalus has a substantial adverse impact on the development of a wide range of specific language abilities.