Previous studies of the neuropsychological consequences of insulin dependent diabetes mellitus (IDDM) have had mixed and often contradictory results, possibly due to the heterogeneity of the samples and neuropsychological measures, and a lack of specific hypotheses. In order to address this problem, we focused on the effect of severe hypoglycemia on memory functioning in a relatively homogeneous sample of childhood-onset IDDM patients. Given the deleterious effects of hypoglycemia on medial temporal lobe structures (e.g., hippocampus) and the relationship between medial temporal damage and declarative memory functioning, we hypothesized that those patients who had experienced severe hypoglycemia would demonstrate impaired declarative memory and spared nondeclarative memory functioning. Results of the study were generally consistent with this hypothesis, although some impact of hypoglycemia was observed on perceptual priming ability. (JINS, 1997, 3, 509–520.)

Associate learning for visual nonverbal and auditory verbal items was examined in 21 children with spastic diplegic cerebral palsy (SDCP) and 28 healthy children using four paired associate tasks. SDCP children showed poorer performance than the comparison group for learning pairs that required visual nonverbal responses, regardless of the stimulus modality. Within the SDCP group, lesion severity was assessed in 17 of the children. Lesion severity was related to the level of performance on paired associate tasks requiring visual nonverbal responses; lesion severity did not reach statistical significance for tasks requiring auditory verbal responses. The study suggests: (1) periventricular white matter regions are important for the development of basic learning processes, such as associative learning, and (2) learning of visual nonverbal material is disproportionately affected following white matter injury early in life. (JINS, 1997, 3, 521–527.)

This study examined the utility of word recognition scores for estimating actual Verbal IQ scores obtained from 1–5 years earlier. Participants were 271 persons remaining normal and 24 initially normal persons who developed cognitive impairment over longitudinal follow-up. A previously published regression equation based on education and the American modification of the National Adult Reading Test (Nelson, 1982) was used to estimate Mayo Verbal IQ. In spite of correlating well with prior obtained scores (r = .7) the predicted score tended to overestimate the obtained Mayo Verbal IQ. A revised equation was developed in the normal sample, which improved accuracy of prediction. Among the 24 persons who developed cognitive impairment over a 5-year span, the revised predicted scores provided reasonable estimates of initial Mayo Verbal IQ. To aid in clinical interpretation, a table of the normal frequencies of predicted Mayo Verbal IQ minus contemporaneously obtained Mayo Verbal IQ is provided. (JINS, 1997, 3, 528–533.)

Current views of long-term memory presume that both the hippocampal complex and the neocortex play interactive, but separate, roles in the storage of memories. While the neocortex is considered the eventual and permanent store for our memories, the encoding of recently experienced events is thought to be initially dependent upon the hippocampus and closely related structures. Neuropsychological studies have demonstrated that damage to the medial temporal lobe results in a retrograde amnesia extending back in time, with better preservation of older memories. The converse pattern has been shown in patients with semantic dementia, who have focal atrophy of the inferolateral temporal neocortex, but relative sparing of the hippocampal complex (Graham & Hodges, 1997). Here we demonstrate that such patients can show relatively preserved new learning on a forced-choice recognition memory test (based on real and chimeric animals), while patients in the early amnestic phase of Alzheimer's disease show severely impaired learning on the same test. This result provides support for the view that new learning is primarily dependent upon the hippocampus and related structures. (JINS, 1997, 3, 534–544.)

We tested the validity of the 48-Pictures Test, a 2-alternative forced-choice recognition test, in detecting exaggerated memory impairments. This test maximizes subjective difficulty, through a large number of stimuli and shows minimal objective difficulty. We compared 17 suspected malingerers to 39 patients with memory impairments (6 amnesic, 15 frontal lobe dysfunctions, 18 other etiologies), and 17 normal adults instructed to simulate malingering on three memory tests: the 48-Pictures Test, the Rey Auditory Verbal Learning Test (RAVLT), and the Rey Complex Figure Test (RCFT). On the 48-Pictures Test, the clinical groups showed good recognition performance (amnesics: 85%; frontal dysfunction: 94%; other memory impairments: 97%), whereas the two simulator groups showed a poor performance (suspected malingerers: 62% correct; volunteer simulators 68% correct). The two other tests did not show a high degree of discrimination between the clinical groups and the simulator groups, except in 2 measures: the 2 simulator groups tended to show a performance decrement from the last recall trial to immediate recognition of the RAVLT and also performed better than the clinical groups on the immediate recall of the RCFT. A discriminant analysis with the latter 2 measures and the 48-Pictures Test correctly classified 96% of the participants. These results suggest that the 48-Pictures Test is a useful tool for the detection of possible simulated memory impairment and that when combined to the RAVLT recall–recognition difference score and to the immediate recall score on the RCFT can provide strong evidence of exaggerated memory impairment. (JINS, 1997, 3, 545–552.)

This is the third symposium to be published in JINS. The idea for the symposium arose following the presentation of a group of papers on pediatric head injury at the February 1996 meeting of the International Neuropsychological Society in Chicago. During that paper session, speakers shared not only their research data, but also the methodological and conceptual dilemmas involved in evaluating the consequences of head injury in children. Several of these dilemmas occur as themes throughout the set of articles presented in the symposium.

Despite considerable sparing of function following some forms of early brain disease, neural plasticity is far from complete. Many children with early brain insults, including those who sustain traumatic brain injury (TBI), are susceptible to both immediate and long-term neurobehavioral impairments. To introduce this symposium, the present article reviews existing research on the effects of 3 age-related factors on outcomes: age at injury, time since injury, and age at testing. Research findings support the hypothesis that development is more adversely affected the younger the child at the time of brain insult. Although we know less about how outcomes are related to the other developmental factors, there is little evidence that sequelae resolve with age. Potential brain mechanisms responsible for age-related differences are explored and methodological problems are considered. Emphasis is placed on the importance of prospective designs, measurement of developmental change, comprehensive assessments of outcome, and evaluation of factors contributing to variability in outcomes, such as premorbid status, type of brain injury, and environmental influences. Papers in this series demonstrate the utility of these methods and shed new light on developmental processes associated with childhood brain insults. (JINS, 1997, 3, 555–567.)

It has been argued that young children's brains are “plastic,” and may sustain substantial brain insult with little loss of function. Recent research suggests that this notion may not apply for generalized cerebral pathology. The present study aimed to evaluate this proposition using a sample of 73 young children, divided into 3 groups: severe head injury (HI; N = 17); mild–moderate HI (N = 32); and noninjured controls (N = 24). Preinjury screening established equivalence across groups for age, sex, preinjury ability, behavioral adjustment, socioeconomic status, and family functioning. Children were evaluated as soon as possible postinjury, and again 12 months postinjury, in three domains: intellectual ability, language, and memory. Results indicated that severe HI was associated with substantial, persisting difficulties in all areas. In contrast, children with mild–moderate HI experienced fewer difficulties, and often performed similarly to controls, both acutely and 12 months postinjury. There was no evidence of differential recovery of function associated with injury severity, with performance increments consistent across groups and probably due to either age-appropriate developmental gains, or test–related practice effects. Poorer outcome at 12 months postinjury was predicted by injury severity primarily, with earlier age at injury, and premorbid ability associated with outcome in specific domains. (JINS, 1997, 3, 568–580.)

Neuropsychological outcome was evaluated in a prospective, longitudinal follow-up study of children age 4 months to 7 years at injury with either mild-to-moderate (N = 35) or severe (N = 44) traumatic brain injury (TBI). Age-appropriate tests were administered at baseline, 6 months, 12 months, and 24 months after the injury. Performance was compared on (1) composite IQ and motor, (2) receptive and expressive language, and (3) Verbal and Perceptual–Performance IQ scores. In comparison to mild-to-moderate TBI, severe TBI in infants and preschoolers produced deficits in all areas. Interactions between task and severity of injury were obtained. Motor scores were lower than IQ scores, particularly after severe TBI. Both receptive and expressive scores were reduced following severe TBI. Expressive language scores were lower than receptive language scores for children sustaining mild-to-moderate TBI. While severe TBI lowered both Verbal and Perceptual– Performance IQ scores, Verbal IQ scores were significantly lower than Perceptual–Performance IQ scores after mild-to-moderate TBI. Mild injuries may produce subtle linguistic changes adversely impacting estimates of Verbal IQ and expressive language. Within the limited age range evaluated within this study, age at injury was unrelated to test scores: The impact of TBI was comparable in children ages 4 to 41 months versus 42 to 72 months at the time of injury. All neuropsychological scores improved significantly from baseline to the 6-month follow-up. However, no further change in scores was observed from 6 to 24 months after the injury. The persistent deficits and lack of catch-up over time suggest a reduction in the rate of acquisition of new skills after severe TBI. Methodological issues in longitudinal studies of young children were discussed. (JINS, 1997, 3, 581–591.)

This article examines the evidence that the effect of head injury on young children may differ from that in adults, in that while in the latter the pattern is of deficits that recover with time since the accident, this is not necessarily the case with very young children. In this group, there may be no evidence of any deficit in the early days or weeks after injury, but the children may fail to develop some skills as quickly as children who have not had a head injury. Results from a series of studies of MHI in preschool children carried out over a more than 10-year period from Auckland Hospital and recently published studies of pediatric MHI from other groups are reviewed. It is concluded from a comparison of these data that there is a need for long-term prospective studies designed within a developmental framework to clarify the issue. (JINS, 1997, 3, 592–597.)

To further investigate the usefulness of 3 purported measures of executive function (EF) in head injured children, we administered the Twenty Questions Test (TQT), Tower of London (TOL), and the Wisconsin Card Sorting Test (WCST) to 151 children who had sustained a closed head injury (CHI) of varying severity about 3 years earlier. In addition, we tested 89 normal controls. Fifty-seven of the patients were included in a longitudinal study that compared performance at 3 months and 36 months. All of the head injured children underwent magnetic resonance imaging for investigational purposes. Severity of CHI, as defined by the lowest Glasgow Coma Scale (GCS) score, affected performance on all 3 EF measures. Focal lesion volume incremented prediction of performance on TOL and WCST, but not TQT. Moderate intercorrelations of the test variables were obtained. Although all three EF measures depicted changes in performance over 3 years, a ceiling effect detracted from the sensitivity of the TOL to the impact of CHI on development. Implications of the findings for clinical applications are discussed. (JINS, 1997, 3, 598–607.)

Within the context of a longitudinal study investigating outcome for children following traumatic brain injury, this paper reports on the utility of neuropsychological testing in predicting academic outcome in children 2 years following traumatic brain injury (TBI). Twenty-nine school-age children who were admitted to hospital after TBI were assessed with a battery of neuropsychological and academic measures at 3 and 24 months postinjury. The neuropsychological battery included measures of memory, learning, and speed of information processing. Academic outcome was assessed in terms of post-TBI change in school placement. According to logistic regression analysis, change in placement from regular to special education at 2 years post-TBI was predicted by injury severity and by neuropsychological performance at 3 months post-TBI. Findings suggest that neuropsychological testing is useful in identifying children with special educational needs subsequent to TBI. (JINS, 1997, 3, 608–616.)

Previous studies of childhood traumatic brain injury (TBI) have emphasized injury-related variables rather than environmental factors as predictors of recovery. We addressed this concern using data collected during a prospective study of children with either TBI or orthopedic injuries (OI) and their families. Participants included 53 children with severe TBI, 56 with moderate TBI, and 80 with OI, all from 6 to 12 years of age at the time of injury. Measures of the preinjury family environment were collected shortly after the injury (baseline). Child cognitive and behavioral outcomes were assessed at baseline and at 6- and 12-month follow-ups. Individual growth curve analyses showed that measures of the preinjury family environment consistently predicted both the level of cognitive and behavioral functioning at 12 months postinjury and the rate of intraindividual change during the 12-month follow-up period, even after taking into account group membership and injury severity. In some cases, the preinjury family environment was a significant moderator of the effect of TBI, buffering its impact in high-functioning families and exacerbating it in low-functioning families. Thus, preinjury environmental factors predict recovery following TBI in children, even after accounting for injury-related variables. (JINS, 1997, 3, 617–630.)

Meta-analysis was used to examine the performance of depressed and Alzheimer-type dementia (DAT) patients on standard and experimental clinical tests of cognitive function. Deficits were found for depression on almost every psychological test. Relative to nondepressed controls, the average deficit was 0.63 of a standard deviation, but the magnitude of the effect varied with the type of test. DAT patients performed worse than depressed patients, with an average effect size of 1.21 standard deviations, but the size of the effect depended on the clinical test. Effect sizes for the comparison between depressives and controls were significantly affected by age, treatment setting, ECT use, severity of depression, and the source of diagnostic criteria, but not by the type of depression. Effect sizes in the comparison of depressives to DAT patients were influenced by age, the severity of depression, and ECT. Depressives performed proportionately worse than controls on tasks with pleasant or neutral, compared with unpleasant content, on speeded compared with nonspeeded tasks, and on vigilance tasks. However, there were no differences in the magnitude of effect size for tests using recall compared with recognition, using categorical compared with noncategorical word lists, on story compared with word comprehension, and using verbal compared with visual material. Relative to DAT patients, depressives performed no better on recall compared to recognition tasks, or verbal compared to visual material. The findings of the review are not consistent with the hypothesis that depression is associated with deficits in effortful processing. A model of psychological deficit in depression as a deficit in speed or attention has more promise. (JINS, 1997, 3, 631–651.)