Matthew A. Lilly

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.

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.

Frontal lobe changes after severe diffuse closed head injury in children: A volumetric study of magnetic resonance imaging

In view of the pathophysiology and biomechanics of severe closed head injury (CHI) in children, we postulated that the frontal lobes sustain diffuse injury, even in the absence of focal brain lesions detected by magnetic resonance imaging (MRI). This study quantitated the morphological effects of CHI on the frontal lobes in children who sustained head trauma of varying severity. The MRI findings of 14 children who had sustained severe CHIs (Glasgow Coma Scale score of < or = 8) were compared with the findings in a matched group of 14 children having sustained mild head injuries (Glasgow Coma Scale score of 13-15). The patients ranged in age from 5 to 15 years at the time of their MRIs, which were acquired at least 3 months postinjury. MRI findings revealed no focal areas of abnormal signal in the frontal lobes. Volumetric analysis disclosed that the total prefrontal cerebrospinal fluid increased and the gray matter volume decreased in the patients with severe CHI, relative to the mildly injured comparison group. Gray matter volume was also reduced in the orbitofrontal and dorsolateral regions of the brains of children with severe CHI, relative to the children who sustained mild head trauma. These volumetric findings indicate that prefrontal tissue loss occurs after severe CHI in children, even in the absence of focal brain lesions in this area. Nearly two-thirds of the children who sustained severe CHIs were moderately disabled after an average postinjury interval of 3 years or more, whereas 12 of the 14 patients with mild CHIs attained a good recovery (2 were moderately disabled) by the time of study.(ABSTRACT TRUNCATED AT 250 WORDS)

Dissociation between delayed alternation and memory after pediatric head injury: Relationship to MRI findings

This study investigated the usefulness of a delayed alternation task in characterizing the cognitive sequelae of closed head injury in children and adolescents. Verbal learning and memory (California Verbal Learning Test) were also studied for comparison. Sixty-two closed head injury patients (mean age, 9.6 years), who were studied after an average postinjury interval of 20 months, were divided according to both their lowest postresuscitation Glasgow Coma Scale score (3 to 8 versus 9 to 15) and age range (5 to 7 years versus 8 to 16 years) at the time of testing. Magnetic resonance imaging was performed to evaluate the relationship of focal brain lesions to cognitive and memory performance. Fifty-six neurologically normal children (mean age, 9.9 years) were tested on the same measures. The results disclosed no relationship between delayed alternation performance and severity of injury. In contrast, verbal memory was impaired in the severely-injured patients, relative to both controls and less severely-injured patients. Frontal lobe (but not extrafrontal) lesion size incremented the Glasgow Coma Scale score in predicting verbal memory, but there was no relationship between focal brain lesions and delayed alternation performance. In contrast to the tendency for more efficient delayed alternation performance in the 5- to 7-year-old subjects than in the 8- to 16-year-old subjects, verbal memory significantly improved with age in the closed head injury and control groups. Notwithstanding our essentially negative findings for delayed alternation, it is possible that this task may be useful for assessing frontal lobe injury in younger children or infants. Our results indicate limitations in extrapolating from nonhuman primate studies of delayed alternation to frontal lobe function in children and adolescents. (J Child Neurol 1994;9:81-89).

Frontal Lobe Changes after Severe Diffuse Closed Head Injury in Children

IN VIEW OF the pathophysiology and biomechanics of severe closed head injury (CHI) in children, we postulated that the frontal lobes sustain diffuse injury, even in the absence of focal brain lesions detected by magnetic resonance imaging (MRI). This study quantitated the morphological effects of CHI on the frontal lobes in children who sustained head trauma of varying severity. The MRI findings of 14 children who had sustained severe CHls (Glasgow Coma Scale score of ≤8) were compared with the findings in a matched group of 14 children having sustained mild head injuries (Glasgow Coma Scale score of 13-15). The patients ranged in age from 5 to 15 years at the time of their MRls, which were acquired at least 3 months postinjury. MRI findings revealed no focal areas of abnormal signal in the frontal lobes. Volumetric analysis disclosed that the total prefrontal cerebrospinal fluid increased and the gray matter volume decreased in the patients with severe CHI, relative to the mildly injured comparison group. Gray matter volume was also reduced in the orbitofrontal and dorsolateral regions of the brains of children with severe CHI, relative to the children who sustained mild head trauma. These volumetric findings indicate that prefrontal tissue loss occurs after severe CHI in children, even in the absence of focal brain lesions in this area. Nearly two-thirds of the children who sustained severe CHls were moderately disabled after an average postinjury interval of 3 years or more, whereas 12 of the 14 patients with mild CHls attained a good recovery (2 were moderately disabled) by the time of study. Although this initial study of brain morphometry after CHI in children was not designed to isolate the contribution of frontal lobe damage to residual disability, further research involving a larger sample is in progress to address this issue.

Effects of transcallosal surgery on interhemispheric transfer of information.

The effects of transcallosal surgery on interhemispheric transfer of information were investigated in five patients who underwent partial section of the corpus callosum for evacuation of a brain tumor. In comparison with normal controls, postoperative findings indicated subtle motor and/or sensory manifestations of hemispheric disconnection which tended to resolve overtime. However, in no case were the disconnection effects disabling in the performance of daily activities.

Classification of brain compartments and head injury lesions by neural networks applied to MRI

An automatic, neural network-based approach was applied to segment normal brain compartments and lesions on MR images. Two supervised networks, backpropagation (BPN) and counterpropagation, and two unsupervised networks, Kohonen learning vector quantizer and analog adaptive resonance theory, were trained on registered T2-weighted and proton density images. The classes of interest were background, gray matter, white matter, cerebrospinal fluid, macrocystic encephalomalacia, gliosis, and “unknown.” A comprehensive feature vector was chosen to discriminate these classes. The BPN combined with feature conditioning, multiple discriminant analysis followed by Hotelling transform, produced the most accurate and consistent classification results. Classifications of normal brain compartments were generally in agreement with expert interpretation of the images. Macrocystic encephalomalacia and gliosis were recognized and, except around the periphery, classified in agreement with the clinicians report used to train the neural network.