Dianne B. Mendelsohn

Narrative Discourse after Closed Head Injury in Children and Adolescents

This study examined narrative discourse in 20 children and adolescents at least 1 year after sustaining a head injury. Narratives were analyzed along the dimensions of language structure, information structure, and flow of information. Severity of impaired consciousness was associated with a significant reduction in the amount of language and information. The most important finding which emerged was the disruption in information structure. This pattern confirms the impression of disorganized discourse in severely injured children. Explanations for the disruption in information structure are explored in terms of the role of vocabulary, memory, and localization of lesion according to magnetic resonance imaging. In view of recent evidence that frontal lobe damage is associated with discourse formulation deficits in adults and is the most common site of focal lesion in closed head injury, we examined discourse patterns in individual patients with frontal lobe lesions. Preliminary data from our single-case studies suggest discourse patterns similar to those reported for adults with frontal lobe injuries.

Dimensions of cognition measured by the tower of London and other cognitive tasks in head‐injured children and adolescents

To determine the factor structure of executive functioning in head‐injured (n = 81) and normal children (n = 102), we administered tests of concept formation and problem solving, plus planning, verbal fluency, design fluency, memory (to evaluate semantic organization), and response modulation using a Go/No‐Go task. The children who sustained closed head injury (CHI) were divided into subgroups who sustained severe (n = 39) and mild/moderate (n = 42) injury. The CHI groups and normal controls were also grouped according to age at the time of testing (6–8, 9–12, and 13–16). The principal components analysis disclosed a five‐factor solution that accounted for 79% of the variance: Conceptual‐Productivity (Factor 1), Planning (Factor 2), Schema (Factor 3), Cluster (Factor 4), and Inhibition (Factor 5). Age had a significant effect on Factors 1, 2, and 5, whereas severity of CHI affected Factors 1,2,4, and 5. Using hierarchial regression in which the Glasgow Coma Scale score, age, and their interaction were ent...

Magnetic resonance imaging in relation to functional outcome of pediatric closed head injury: A test of the Ommaya-Gennarelli model

OBJECTIVE To characterize late neuropathological findings of pediatric closed head injury (CHI), to assess depth of brain lesion in relation to acute severity, and to assess long-term outcome to test the Ommaya-Gennarelli model. METHODS Magnetic resonance imaging (MRI) at least 3 months postinjury in a prospective sample (n 5 169) and at least 3 years after CHI in a retrospective sample (n 5 82) was studied. Lesion volume was measured by planimetry. Acute CHI severity was measured by the Glasgow Coma Scale. Patients were classified according to the depth of the deepest parenchymal lesion into no lesion, subcortical, and deep central gray/brain stem groups. The outcomes were assessed by the Glasgow Outcome Scale and the Vineland Adaptive Behavior Scale, which were performed at the time of the MRI in the retrospective sample and up to 3 years postinjury in the prospective sample. RESULTS Focal brain lesions were present in 55.4% of the total sample. Depth of brain lesion was directly related to severity of acute impairment of consciousness and inversely related to outcome, as measured by both the Glasgow Outcome Scale and the Vineland Adaptive Behavior Scale. A rostrocaudal gradient of hemispheric lesion frequency was observed, whereas the posterior lesions of the corpus callosum were particularly common. Total lesion volume could not explain the depth of lesion effect. CONCLUSION Our findings extend support for the Ommaya-Gennarelli model to pediatric CHI, indicating that depth of brain lesion is related to functional outcome. The relative frequency of focal brain lesions revealed by late MRI is higher than that of previous findings using acute computed tomography. Future investigations could explore whether depth of lesion observed using late MRI is sensitive to neuroprotective interventions.

Word fluency in relation to severity of closed head injury, associated frontal brain lesions, and age at injury in children

Effects of closed head injury (CHI) severity, focal brain lesions, and age at injury on word fluency (WF) were studied longitudinally in 122 children (78 severe, 44 mild); 112 CHI patients (68 severe, 44 mild CHI) and 104 uninjured normal controls participated in a cross-sectional study. WF was measured by asking the child to generate as many words as possible beginning with a designated letter within 60 s, repeated for three letters. Intellectual ability, receptive vocabulary, narrative discourse, and word list recall were also measured. Results of the cross-sectional study showed a significant group effect with poorer WF in severe CHI than mild CHI and control groups. Growth curve analysis of longitudinal data revealed an interaction of age, follow-up interval, and CHI severity as WF recovery was slower after severe CHI in younger children as compared to severe CHI in older children or mild CHI in younger children. An interaction of left frontal lesion with age and interval indicated a more adverse effect on WF in older children. Right frontal lesion effect was nonsignificant and did not interact with age. Correlations of WF with receptive vocabulary, word list recall, and narrative discourse were moderate and weak with estimated intellectual ability. Differences in focal lesion effects after traumatic versus nontraumatic brain injury in children, the contribution of diffuse white matter injury, reduced opportunity for language development, and functional commitment of left frontal region at time of CHI were discussed.

Reduction of corpus callosum growth after severe traumatic brain injury in children

Objective: To study effects of closed head injury (CHI) severity on development of corpus callosum (CC) in children, using MRI. Background: Vulnerability of CC to diffuse axonal injury has been shown in adults and children by neuropathologic and MRI studies. Given continued development of CC through the second decade, serial MRI could characterize effects of CHI on CC growth in children. Methods: MRI performed at 3 and 36 months after severe (mean age = 10.3 years, n = 25) and mild to moderate (mean age = 9.7 years, n = 28) CHI. Mild to moderate and severe CHI groups did not differ in demographic features. Morphometry of T1-weighted midsagittal CC by two operators with satisfactory interrater reliability yielded uncorrected and corrected CC volume. Results: An interaction of occasion with CHI severity was present as CC area decreased from 3 to 36 months in severely injured children and increased in the mild to moderate CHI group. Uncorrected CC area was correlated with acute CHI severity and functional outcome at 36 months postinjury. Conclusions: Morphometric measurement of CC area provides a useful index of diffuse injury, which is related to functional outcome of CHI in children.

Behavioral Outcomes After Pediatric Closed Head Injury: Relationships With Age, Severity, and Lesion Size

This study investigated the behavioral outcomes and adaptive functioning of 138 children with mild to severe closed head injury in the 6- to 16-year age range. Each child was evaluated with the Personality Inventory for Children-Revised. A subset of this sample (n = 77) received the Vineland Adaptive Behavior Scales. Results revealed little evidence for group differences based on severity of closed head injury on scales associated with psychopathology on the Personality Inventory for Children-Revised. However, children with severe closed head injury were viewed as experiencing more difficulties than children with mild-moderate closed head injury on those components of the Personality Inventory for Children-Revised most closely associated with cognitive functions. In addition, on the Vineland Adaptive Behavior Scales, severely injured children had lower scores on the Communication and Socialization scales than children with mild-moderate injury. Relationships between the size of frontal and extrafrontal lesions from concurrent magnetic resonance imaging and behavioral outcomes were not apparent. This study suggests that outcome measures assessing adaptive behavior and cognitive functions are more sensitive to severity of closed head injury than parent-based scales of internalizing and externalizing psychopathology. (J Child Neurol 1996; 11: 283-290).

Late MRI after head injury in children: relationship to clinical features and outcome

To characterize the brain pathology in relation to long-term outcome after pediatric head injury, 55 children were studied by magnetic resonance imaging (MRI) at least 3 months after sustaining moderate to severe closed head injury (CHI). Thirty-nine of the patients had abnormal signal intensity consistent with residual brain lesions, including 28 children with lesions involving the frontal lobes. The clinical features of children with frontal lesions, extrafrontal lesions, and diffuse injury were compared. The analysis disclosed that children with frontal lobe lesions were more frequently disabled than children who sustained diffuse injury. Our MRI findings indicate that residual brain lesions are more common after moderate to severe CHI in children than previously thought and that the frontal lobes are most frequently involved. Further investigation is indicated to elucidate whether distinctive cognitive and behavioral sequelae are associated with frontal lobe lesions in children.

Corpus callosum damage and interhemispheric transfer of information following closed head injury in children.

We evaluated the relationship of corpus callosum atrophy and/or lesions on magnetic resonance imaging (MRI) to functional hemispheric disconnection following closed head injury (CHI) in 51 pediatric patients, including mild CHI, moderate to severe CHI with extracallosal lesions, and moderate to severe CHI with callosal atrophy and/or lesions. Interhemispheric transfer of information was assessed using auditory, motor, tactile, and visual tests in patients and in 16 uninjured children. Total and regional callosal areas were measured from the midsagittal MRI slice by morphometry. The corpus callosum lesion group demonstrated a greater right ear advantage on verbal dichotic listening than all other groups. Areas of the posterior corpus callosum were negatively correlated with laterality indices of verbal dichotic listening performance and tachistoscopic identification of verbal material. The relationship of corpus callosum atrophy and/or lesions to asymmetry in dichotic listening is consistent with previous investigation of posttraumatic hemispheric disconnection effects in adults.

Corpus callosum lesions after closed head injury in children: MRI, clinical features and outcome

SummaryThirty-four children who sustained moderate to severe closed head injury underwent magnetic resonance imaging (MRI). Eight (24%) had MRI evidence of corpus callosum injury, most commonly within the posterior body and splenium. In contradistinction to reports in adults, there was no definite relationship between callosal injury and lower initial Glasgow Coma Scale scores, nor was there a significantly higher incidence of primary brain-stem lesions, diffuse axonal shear injury or intraventricular hemorrhage. In none of these 8 children did the initial admission computed tomography show evidence of callosal injury. Callosal injuries on MRI are not necessarily a poor prognostic finding, the majority of the 8 children showing good functional recovery.

Hypoxia imaging in brain tumors

Assessment of the oxygenation status of brain tumors has been studied increasingly with imaging techniques in light of recent advances in oncology. Tumor oxygen tension is a critical factor influencing the effectiveness of radiation and chemotherapy and malignant progression. Hypoxic tumors are resistant to treatment, and prognostic value of tumor oxygen status is shown in head and neck tumors. Strategies increasing the tumor oxygenation are being investigated to overcome the compromising [figure: see text] effect of hypoxia on tumor treatment. Administration of nicotinamide and inhalation of various high oxygen concentrations have been implemented. Existing methods for assessment of tissue oxygen level are either invasive or insufficient. Accurate and noninvasive means to measure tumor oxygenation are needed for treatment planning, identification of patients who might benefit from oxygenation strategies, and assessing the efficacy of interventions aimed to increase the radiosensitivity of tumors. Of the various imaging techniques used to assess tissue oxygenation, MR spectroscopy and MR imaging are widely available, noninvasive, and clinically applicable techniques. Tumor hypoxia is related closely to insufficient blood flow through chaotic and partially nonfunctional tumor vasculature and the distance between the capillaries and the tumor cells. Information on characteristics of tumor vasculature such as blood volume, perfusion, and increased capillary permeability can be provided with MR imaging. MR imaging techniques can provide a measure of capillary permeability based on contrast enhancement and relative cerebral blood volume estimates using dynamic susceptibility MR imaging. Blood oxygen level dependent contrast MR imaging using gradient echo sequence is intrinsically sensitive to changes in blood oxygen level. Animal models using blood oxygen level-dependent contrast imaging reveal the different responses of normal and tumor vasculature under hyperoxia. Normobaric hyperoxia is used in MR studies as a method to produce MR contrast in tissues. Increased T2* signal intensity of brain tissue has been observed using blood oxygen level-dependent contrast MR imaging. Dynamic blood oxygen level-dependent contrast MR imaging during hyperoxia is suggested to image tumor oxygenation. Quantification of cerebral oxygen saturation using blood oxygen level-dependent MR imaging also has been reported. Quantification of cerebral blood oxygen saturation using MR imaging has promising clinical applications; however, technical difficulties have to be resolved. Blood oxygen level dependent MR imaging is an emerging technique to evaluate the cerebral blood oxygen saturation, and it has the potential and versatility to assess oxygenation status of brain tumors. Upon improvement and validation of current MR techniques, better diagnostic, prognostic, and treatment monitoring capabilities can be provided for patients with brain tumors.