Verbal learning and memory following pediatric closed-head injury

Differences in attention, executive functioning, and memory in children with and without ADHD after severe traumatic brain injury

Although the development of Attention Deficit Hyperactivity Disorder (ADHD) after traumatic brain injury (TBI) has been described, it is unknown whether children with TBI and ADHD have greater neuropsychological impairments than children with TBI alone. This study examines attention, executive functioning, and memory in children with TBI-only and TBI + ADHD. Caregivers of 82 children with severe TBI completed structured psychiatric interviews at enrollment to diagnose premorbid ADHD and one-year after injury to diagnose post-injury ADHD. Children underwent neuropsychological testing one year after injury. One memory measure significantly differentiated children with TBI-only from children with newly developed ADHD [secondary ADHD (S-ADHD)] and those with premorbid ADHD that persisted after injury [persisting ADHD (P-ADHD)]. Compared with the TBI-only group, children with TBI + ADHD had worse performance on measures of attention, executive functioning, and memory. Results reveal that in children with severe TBI, the behavioral diagnosis of ADHD is associated with more difficulty in attention, executive functioning, and memory. Additionally, results suggest greater deficits in memory skills in the S-ADHD group compared with the P-ADHD group. Although findings provide preliminary support for distinguishing P-ADHD from S-ADHD, further research is needed to investigate neuropsychological differences between these subgroups of children with severe TBI.

Frontal and temporal morphometric findings on MRI in children after moderate to severe traumatic brain injury

In vivo MRI volumetric analysis enables investigators to evaluate the extent of tissue loss following traumatic brain injury (TBI). However, volumetric studies of pediatric TBI are sparse, and there have been no volumetric studies to date in children examining specific subregions of the prefrontal and temporal lobes. In this study, MRI volumetry was used to evaluate brain volume differences in the whole brain, and prefrontal, temporal, and posterior regions of children following moderate to severe TBI as compared to uninjured children of similar age and demographic characteristics. The TBI group had significantly reduced whole brain, and prefrontal and temporal regional tissue volumes as well as increased cerebrospinal fluid (CSF). Confidence interval testing further revealed group differences on gray matter (GM) and white matter (WM) in the superior medial and ventromedial prefrontal regions, WM in the lateral frontal region, and GM, WM, and CSF in the temporal region. Whole brain volume and total brain GM were reduced, and total ventricular volume, total CSF volume, and ventricle-to-brain ratio (VBR) were increased in the TBI group. Additional analyses comparing volumetric data from typically developing children and subgroups of TBI patients with and without regional focal lesions suggested that GM loss in the frontal areas was primarily attributable to focal injury, while WM loss in the frontal and temporal lobes was related to both diffuse and focal injury. Finally, volumetric measures of preserved frontotemporal tissue were related to functional recovery as measured by the Glasgow Outcome Scale (adapted for children) with greater tissue preservation predicting better recovery.

Hierarchical linear modeling of California Verbal Learning Test--Children's Version learning curve characteristics following childhood traumatic head injury

California Verbal Learning Test-Children's Version (CVLT-C) indices have been shown to be sensitive to the neurocognitive effects of traumatic brain injury (TBI). The effects of TBI on the learning process were examined with a growth curve analysis of CVLT-C raw scores across the 5 learning trials. The sample with history of TBI comprised 86 children, ages 6-16 years, at a mean of 10.0 (SD=19.5) months postinjury; 37.2% had severe injury, 27.9% moderate, and 34.9% mild. The best-fit model for verbal learning was with a quadratic function. Greater TBI severity was associated with lower rate of acquisition and more gradual deceleration in the rate of acquisition. Intelligence test index scores, previously shown to be sensitive to severity of TBI, were positively correlated with rate of acquisition. Results provide evidence that the CVLT-C learning slope is not a simple linear function and further support for specific effects of TBI on verbal learning.

Predictors of neuropsychological test performance after pediatric traumatic brain injury

The influence of neurological and demographic variables on neuropsychological test performance was examined in 100 9-to 16-year-old children with traumatic brain injury (TBI). Regression analyses were conducted to determine the relative contributions of coma, neuroimaging findings, ethnicity, socioeconomic status, and gender to variance in performance on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III), California Verbal Learning Test--Children's Version (CVLT-C), and the Children's Category Test. Both neurological and demographic variables contributed to performance on various WISC-III factor index scores as well as the CVLT-C. No evidence for a moderating effect of demographic variables was found, but speed of information processing mediated the effect of neurological and demographic variables on CLVT-C performance. It is concluded that demographic variables have an incremental effect on the neuropsychological test performance of children with TBI above and beyond the influence of injury severity.

Implicit and Explicit Memory in Children With Congenital and Acquired Brain Disorder

Implicit and explicit memory were examined in 8- to 15-year-old children with myelomeningocele and shunted hydrocephalus, severe traumatic brain injuries, or orthopedic injuries. Each group included between 22 and 29 children. Children completed a fragmented picture identification task to assess perceptual priming and a semantic decision-making task to assess conceptual priming. Each task also assessed procedural learning as well as explicit recall and recognition. All 3 groups showed significant perceptual and semantic priming of similar magnitude. In contrast, both brain-disordered groups displayed poorer explicit memory than did the comparison group. No group showed significant procedural learning on either task. Age and IQ were stronger predictors of explicit recall than of implicit memory. The findings indicate that implicit memory is relatively intact in many children with congenital and acquired brain disorders, despite deficits in explicit memory, and support the existence of separate memory systems in children.

Implicit Strategy Affects Learning in Children With Heavy Prenatal Alcohol Exposure

BACKGROUND

Learning and memory deficits are commonly reported in children with heavy prenatal alcohol exposure. Our recent work suggested that children with heavy prenatal alcohol exposure retained information as well as controls on a verbal learning test but not on a test of nonverbal learning and memory. To better understand the cause of this differential pattern of performance, the current study re-analyzed data from our previous study to determine if the presence of an implicit learning strategy may account, at least in part, for the finding of spared retention.

METHODS

The current study examined verbal learning and memory abilities in 35 children with Fetal Alcohol Spectrum Disorders (FASD) and 34 nonexposed controls (CON) matched for age (9-16 years), sex, ethnicity, handedness, and socioeconomic status. Groups were compared on two measures of verbal learning, one with an implicit strategy (California Verbal Learning Test-Children's Version; CVLT-C) and one without (Verbal Learning subtest of the Wide Range Assessment of Memory and Learning; VL-WRAML).

RESULTS

Children with FASD learned less information overall than children in the CON group. Both groups learned a greater percentage of information and reached a learning plateau earlier on the CVLT-C compared with the VL-WRAML. Groups also showed comparable rates of retention after a delay on the CVLT-C. In contrast, on the VL-WRAML, children with FASD showed poorer retention rates than children in the CON group. Interestingly, children with FASD did not differ from children in the CON group on CVLT-C semantic clustering scores for learning trials 1 through 3, and greater utilization of semantic clustering was correlated with better learning and memory performance in both groups. This overall pattern of results was not related to overall intellectual level.

CONCLUSIONS

The finding of spared retention of verbal information on the CVLT-C in our earlier studies may be related to test characteristics of the CVLT-C rather than a finding of spared verbal retention per se, given that spared retention was not found on a separate test of verbal learning and memory without an implicit learning strategy. These results suggest that the use of an implicit strategy positively affected the ability of alcohol-exposed children to learn and retain new verbal information.

Verbal learning and memory after childhood stroke

Verbal learning and memory (VLM) following pediatric stroke was characterized in a cross-sectional neuropsychological and neuroimaging study of 26 subjects, aged 5 to 17, with a history of pediatric stroke and 26 age, SES, and gender matched orthopedic controls. Further comparisons were made between the VLM profiles of stroke subjects with right versus left hemisphere lesions and early (> 12 months) versus late (12 months) strokes. Overall, stroke subjects scored significantly lower than control subjects on several VLM indices (California Verbal Learning Test-Children; CVLT-C), as well as on measures of intellectual functioning (IQ) and auditory attention/working memory (Digit Span). Subgroup analyses of the stroke population found no significant differences in VLM, Digit Span, Verbal IQ or Performance IQ when left-hemisphere lesion subjects were compared to right-hemisphere lesion subjects. In contrast, early strokes were associated with significantly fewer words recalled after delay, reduced discriminability (fewer correct hits relative to false positive errors on recognition testing), and relatively worse auditory attention/working memory scores (Digit Span). These findings indicate that pediatric stroke subjects demonstrated more VLM impairment than control subjects, and early strokes were associated with greater recall and recognition deficits. In stark contrast with adult-onset stroke, both left- and right-hemisphere lesions during childhood resulted in similar VLM performance.

Performance discrepancies on the California Verbal Learning Test-Children's Version (CVLT-C) in children with traumatic brain injury

One hundred sixty-seven children with traumatic brain injury (TBI), selected from an 8-year series of consecutive referrals to a Midwestern rehabilitation hospital, completed the California Verbal Learning Test-Children's Version (CVLT-C) and the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) within 1 year after injury. A large proactive interference (PI) effect, defined as performance on the second list that was at least 1.5 standard deviations below that on the 1st one, was statistically significantly more common in this clinical sample (21%) than in the CVLT-C standardization sample (11%). Other performance discrepancies, including retroactive interference, rapid forgetting, and retrieval problems, occurred at approximately the same rate in the clinical and standardization samples. Children with anterior cerebral lesions were about 3 times less likely to have a large PI effect than children without such lesions, but the former group performed worse on the first CVLT-C list. The impact of pediatric TBI on a wide range of CVLT-C quantitative variables was mediated by speed of information processing, as assessed by the WISC-III Processing Speed factor index. It is concluded that failure to release from PI is somewhat common, although certainly not universal, in children with TBI. Unlike with adults, anterior cerebral lesions are not associated selectively with an increased risk for PI after pediatric TBI but rather with a reduced efficiency of allocation of cognitive resources. Deficits in speed of information processing appear to be primarily responsible for the learning deficits on the CVLT-C after pediatric TBI.

Psychosocial outcome of TBI in children with unilateral frontal lesions

To evaluate effects of unilateral frontal lesions on psychosocial and global outcome of traumatic brain injury (TBI) in children, Study 1 compared matched groups of 22 school aged children who had sustained TBI either with or without unilateral frontal lesions. Study 2 evaluated effects of unilateral extrafrontal lesions in 18 TBI patients as compared with 18 nonlesional TBI patients. Communication, Daily Living, and Socialization domains and the Maladaptive Behavior Scale of the Vineland Adaptive Behavior Scales (VABS) were used to assess psychosocial outcome, and the Glasgow Outcome Scale (GOS) measured global outcome. All patients underwent magnetic resonance imaging at least 3 months post injury. Children with frontal lesions had worse scores on the Daily Living and Socialization domains and a higher frequency of maladaptive behavior than those without frontal lesions, but there was no difference in cognitive function. Disability was twice as common in the frontal lesion group relative to children without frontal lesions. Volume of frontal lesion was related to the Socialization domain. Side of lesion had no effect, nor did presence of an extrafrontal lesion (Study 2). Unilateral frontal lesions adversely affect late psychosocial outcome of TBI in children.

Memory functioning following traumatic brain injury in children with premorbid learning problems

This study examines the memory functioning of 25 children who sustained a traumatic brain injury (TBI) and who had prior learning problems, 48 children with TBI who did not have prior learning problems, and 23 noninjured controls. The children with TBI and prior learning problems displayed significantly worse memory abilities than both the control participants and the children with TBI and no prior learning problems. They differed significantly from these 2 groups on measures of general memory, verbal memory, sound-symbol learning, and attention. The results suggest that children with premorbid learning problems who sustain TBI have less cognitive reserve and a lower threshold for the expression of cognitive impairments in areas that reflect preexisting learning and language problems, compared to children without premorbid learning problems.

Gender as a moderator of memory after traumatic brain injury in children

OBJECTIVE

To explore the possibility that gender has a moderating effect on memory after pediatric traumatic brain injury (TBI).

DESIGN

Controlled group study. Gender effects between and within groups were evaluated by means of effect size comparisons and hierarchical regression analysis.

SETTING

Regional rehabilitation center.

PARTICIPANTS

Seventy children with TBI, selected from a 4-year series of consecutive referrals, and 70 demographically matched controls.

MAIN OUTCOME MEASURES

Screening version of the Wide Range Assessment of Memory and Learning (WRAML-S) and the Wechsler Intelligence Scale for Children-Third Edition (WISC-III).

RESULTS

Boys with TBI performed worse than girls with TBI, and worse than their counterparts in the control group, on the WRAML-S. There was no gender effect in the control group. Gender explained an additional 9% of the variance in WRAML-S performance over and above injury severity and age variables. However, gender differences were largely attenuated when speed of information processing, as assessed by the WISC-III, was used as a covariate.

CONCLUSION

The effect of TBI on children's memory appears to be moderated by gender and may be mediated by speed of information processing.

Predicting neuropsychologic outcome after traumatic brain injury in children

The ability to predict long-term neurologic and neuropsychologic outcomes in 22 children, ages 1 week to 14 years at the time of traumatic brain injury, was investigated using proton magnetic resonance spectroscopy acquired post injury and compared with standardized neurologic, intellectual, and neuropsychologic testing done 1-7 years later. Clinical indicators of acute injury severity including age at injury, electroencephalography, spectroscopy metabolite ratio variables (N-acetyl aspartate/choline, choline/creatine) and lactate presence accurately classified children as functioning above or below the average range for most intellectual and neuropsychologic outcome measures. Combined clinical and spectroscopy variables accounted for approximately 50% of the variance in cognitive and neuropsychologic outcome confirming the validity of their predictive use. Of the injury severity indictors, presence of lactate is a particularly important prognostic marker of poor long-term intellectual and neuropsychologic functioning. Our findings indicate the potential for providing accurate estimates of long-term intellectual and neuropsychologic function after traumatic brain injury in infants and children using proton magnetic resonance spectroscopy in combination with clinical variables.

Gender differences in learning and memory after pediatric traumatic brain injury

Thirty boys and 30 girls who sustained a traumatic brain injury (TBI) were evaluated within 1 year post injury with the California Verbal Learning Test-children's Version (CVLT-C; D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1994). Boys had statistically significantly lower performance on the CVLT-C than girls in the absence of statistically significant group differences on various demographic and neurological variables. Although the effect size for this difference was modest (eta2 = .09), gender accounted for a statistically significant amount of the variance (5%) in CVLT-C scores in addition to effects of injury severity and age. It is concluded that male gender is associated with an increased risk for retrieval deficits after pediatric TBI, possibly because of reduced speed or efficiency of information processing.

Language development in children with spina bifida

Spina bifida meningomyelocele (SBM) is the most common severely disabling birth defect in North America. It is a disorder of the central nervous system that includes, in addition to the defining spinal dysraphism, congenital malformations of the cerebellum and corpus callosum that, along with hydrocephalus, produces a range of cognitive and motor difficulties, including language. In the language domain, many children with SBM demonstrate adequate development of language at the level of form and content (grammar and lexicon). However, most children with SBM experience significant difficulties in the construction of meaning and in pragmatic communication, both of which require flexible language processing in real time. Assessment and intervention should specifically attend to the development of meaning construction and semantic-pragmatic communication.

Acute effects of irradiation on cognition: changes in attention on a computerized continuous performance test during radiotherapy in pediatric patients with localized primary brain tumors

PURPOSE

To assess sustained attention, impulsivity, and reaction time during radiotherapy (RT) for pediatric patients with localized primary brain tumors.

METHODS AND MATERIALS

Thirty-nine patients (median age 12.3 years, range 5.9-22.9) with primary brain tumors were evaluated prospectively using the computerized Conners' continuous performance test (CPT) before and during conformal RT (CRT). The data were modeled to assess the longitudinal changes in the CPT scores and the effects of clinical variables on these changes during the first 50 days after the initiation of CRT.

RESULTS

The CPT scores exhibited an increasing trend for errors of omission (inattentiveness), decreasing trend for errors of commission (impulsivity), and slower reaction times. However, none of the changes were statistically significant. The overall index, which is an algorithm-based weighted sum of the CPT scores, remained within the range of normal throughout treatment. Older patients (age >12 years) were more attentive (p < 0.0005), less impulsive (p < 0.07), and had faster reaction times (p < 0.001) at baseline than the younger patients. The reaction time was significantly reduced during treatment for the older patients and lengthened significantly for the younger patients (p < 0.04). Patients with a shunted hydrocephalus (p < 0.02), seizure history (p < 0.0006), and residual tumor (p < 0.02) were significantly more impulsive. Nonshunted patients (p < 0.0001), those with more extensive resection (p < 0.0001), and patients with ependymoma (p < 0.006) had slower initial reaction times.

CONCLUSION

Children with brain tumors have problems with sustained attention and reaction time resulting from the tumor and therapeutic interventions before RT. The reaction time slowed during treatment for patients <12 years old. RT, as administered in the trial from which these data were derived, has limited acute effects on changes in the CPT scores measuring attention, impulsiveness, and reaction time.

Child clinical/pediatric neuropsychology: some recent advances

The neuropsychological assets and deficits of several types of pediatric neurological disease, disorder, and dysfunction are described. These are examined from the perspective of the syndrome of nonverbal learning disabilities (NLD) and the "white matter model" designed to explain its complex manifestations. It is concluded that children with some of these diseases exhibit the NLD phenotype, whereas others do not. For the most part, the diseases in which the NLD phenotype is particularly evident are those wherein it has been demonstrated that perturbations of white matter (long myelinated fibers) are particularly prominent.

Porteus Maze performance following traumatic brain injury in children

To investigate planning in traumatically brain injured children, the authors gave the Porteus Maze Test (PMT; S. D. Porteus, 1959) to 276 pediatric patients who had sustained a traumatic brain injury (TBI) at least 3 years previously. Sensitivity of the PMT to TBI severity, age at test, and volume of focal brain lesions detected by magnetic resonance imaging was also studied. The Peabody Picture Vocabulary Test-Revised (L. M. Dunn & L. M. Dunn, 1981) was also administered as a control measure. Results indicated that the PMT was highly sensitive to TBI severity and to volume of circumscribed prefrontal lesions. In contrast to the PMT data, receptive vocabulary was related to injury severity but not to discrete prefrontal lesions. Implications for mechanisms of cognitive deficit after TBI in children are discussed.

Volume of focal brain lesions and hippocampal formation in relation to memory function after closed head injury in children

OBJECTIVES

(1) A study of verbal learning and memory in children who had sustained a closed head injury (CHI) at least 3 months earlier. (2) To relate memory function to focal brain lesion and hippocampal formation volumes using morphometric analysis of MRI.

METHODS

A group of 245 children who had been admitted to hospital for CHI graded by the Glasgow coma scale (GCS), including 161 patients with severe and 84 with mild CHI completed the California verbal learning test (CVLT) and underwent MRI which was analysed for focal brain lesion volume independently of memory test data. Brain MRI with 1.5 mm coronal slices obtained in subsets of 25 patients with severe and 25 patients with mild CHI were analysed for hippocampal formation volume. Interoperator reliability in morphometry was satisfactory.

RESULTS

Severity of CHI and age at study significantly affected memory performance. Regression analysis showed that bifrontal, left frontal, and right frontal lesion volumes incremented prediction of various learning and memory indices after entering the GCS score and age into the model. Extrafrontal lesion volume did not contribute to predicting memory performance.

CONCLUSIONS

Prefrontal lesions contribute to residual impairment of learning and memory after severe CHI in children. Although effects of CHI on hippocampal formation volume might be difficult to demonstrate in non-fatal paediatric CHI, further investigation using functional brain imaging could potentially demonstrate hippocampal dysfunction.

Long-term dysfunction following diffuse traumatic brain injury in the immature rat

Children often suffer sustained cognitive dysfunction after severe diffuse traumatic brain injury (TBI). To study the effects of diffuse injury in the immature brain, we developed a model of severe diffuse impact (DI) acceleration TBI in immature rats and previously described the early motor and cognitive dysfunction posttrauma. In the present study, we investigated the long-term functional ability after DI (150 gm/2 m) compared to sham in the immature (PND 17) rat. Beam balance and inclined plane latencies were measured daily for 10 days after injury to assess gross vestibulomotor function. The Morris water maze (MWM) paradigm was evaluated monthly up to 3 months after DI and sham injuries. Reduced latencies on the balance beam and inclined plane were observed in DI rats (p < 0.05 vs. sham [n = 10 per group]) at 24 h and persisted for 10 days postinjury. DI produced sustained MWM performance deficits (p < 0.05 vs. sham) as indicated by the greater latencies to find the hidden platform remarkably through 90 days after injury. Lastly, the brain and body weights of the injured animals were less than sham (p < 0.05) after 3 months. We conclude that a diffuse TBI in the immature rat: (a) created a consistent, marked, but reversible motor deficit up to 10 days following injury; (b) produced a long-term, sustained performance deficit in the MWM up to 3 months posttrauma; and (c) affected body and brain weight gain in the developing rat through 3 months after injury. This TBI model should be useful for the testing of novel therapies and their effect on long-term outcome and development in the immature rat.

Posttraumatic stress symptoms in children following orthopedic or traumatic brain injury

Examined posttraumatic stress (PTS) symptoms in children following pediatric traumatic brain injury (TBI). Children (ages 6-12) with TBI (n = 81) and orthopedic injury (OI; n = 59) were assessed 6 and 12 months postinjury. Parents of children with severe TBI reported higher levels of child PTS symptoms than did parents of children with moderate TBI or OI at the 6- and 12-month follow-ups. Group differences in child-reported PTS symptoms emerged at the 12-month follow-up with higher symptom levels reported by children with severe TBI than by those with moderate TBI or OI. At both follow-ups, rates of clinically significant symptom levels were higher in the severe TBI group than in the moderate TBI or OI groups. The group differences in parent and child reports were significant even after taking ethnicity, social disadvantage, and age at injury into account. Parent and child reports of child PTS symptoms were related to family socioeconomic status. Implications for clinical intervention with children and families following pediatric TBI are discussed.

Applying Luria's diagnostic principles in the neuropsychological assessment of children

The first part of this article examines the theoretical justification for applying Luria's approach in the assessment of children. It is concluded that Luria's concepts of functional systems and the principle of specifying primary and secondary deficits may be applied to children. However, the selection of functional components to assess should be based on traditions of child neuropsychology rather than on Luria's assessment of adults. In addition, the tendency for comorbid disorders, mechanisms of neural adaptation to damage, and the prevalent types of brain abnormality in children render brain-behavior relationships more complex in children than in adults. The second part of the article describes how Luria's methods were adapted for use with children. An assessment, NEPSY, was developed by integrating Luria's views with contemporary child neuropsychological traditions. The NEPSY includes 27 homogeneous and psychometrically developed subtests, standardized in the United States and Finland for the age range of 3 to 12 years. The rationale of analyzing disorders of cognitive processes through a comprehensive and systematic assessment of their components, characteristic of Luria's approach, was preserved, but more specific principles of diagnosis were modified. Research findings obtained with a previously published, Finnish NEPSY version are presented.

Predicting premorbid neuropsychological functioning following pediatric traumatic brain injury

This study examined the prediction of premorbid neuropsychological functioning using data from an ongoing prospective study of traumatic brain injuries (TBI) in children ages 6 to 12 years. Prediction equations were derived based on 80 children with orthopedic injuries (OI), who served as a comparison group for the children with TBI. Collectively, parent ratings of premorbid school performance, maternal ethnicity, family socioeconomic status, and children's word recognition skill predicted from 13% to 45% of the variance in three measures of neuropsychological functioning. The regression equations were used to compute predicted scores among 109 children with TBI. Actual scores fell significantly below predicted scores among children with TBI, and the magnitude of the deficits was correlated with injury severity. Premorbid neuropsychological functioning can be predicted in children with TBI, but with less precision than would be desirable for clinical purposes.

Motor and cognitive functional deficits following diffuse traumatic brain injury in the immature rat

To determine the motor and cognitive deficits following a diffuse severe traumatic brain injury (TBI) in immature Sprague Dawley rats (17 days), four groups of animals were injured at different severity levels using a new closed head weight drop model: (sham, severe injury [SI: 100 g/2 m], SH [SI + hypoxemia (30 min of an FiO2 of 8% posttrauma)], and ultra severe injury [US: 150 g/2 m]). Latency on beam balance, grip test performance, and maintenance of body position on an inclined board were measured daily after injury to assess vestibulomotor function. Cognitive function was assessed on days 11-22 using the Morris water maze (MWM). Balance beam latency and inclined plane body position were reduced in both SI and SH rats (n = 20) (p < 0.05 vs. sham) (maximally at 24 h), and lasted 3-4 day postinjury; however, SH did not differ from SI. In the US group (n = 10), motor deficits were profound at 24 h (p < 0.05 vs. all other groups) and persisted for 10 days. The groups did not differ on grip test. In cognitive performance, there were no differences between sham, SI, and SH. US, however, produced significant cognitive dysfunction (vs. sham, SI, and SH), specifically, greater latencies to find the hidden platform through 22 days. Swim speeds were not significantly different between any of the injury groups and shams. These data indicate that (1) beam balance, inclined plane and MWM techniques are useful for assessing motor and cognitive function after TBI in immature rats; (2) SI produces motor but not cognitive deficits, which was not augmented by transient hypoxia; and (3) US created a marked but reversible motor deficit up to 10 days, and a sustained cognitive dysfunction for up to 22 days after TBI.