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.     

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.     

Attentional-inhibitory control and social-behavioral regulation after childhood closed head injury: do biological, developmental, and recovery variables predict outcome?

Attentional-inhibitory control and social-behavioral regulation are two outcome domains commonly impaired after childhood closed head injury (CHI). We compared neuropsychological tests of attentional-inhibitory control (vigilance, selective attention, response modulation) and social discourse and intentionality (inferencing, figurative language, and speech acts) with parent ratings of attention and behavioral regulation in relation to four injury-related variables: age at CHI, time since CHI, CHI injury severity, and frontal lobe injury moderated by CHI severity. Participants were 105 school-aged children in the chronic stage of CHI, divided into mild, moderate, and severe injury severity groups, and further subdivided according to frontal lobe injury. Outcome indices were imperfectly correlated in the group as a whole, although several relations between neurocognitive tests and parent ratings were observed within CHI subgroups. Different domains of cognitive function had different predictors. For attentional-inhibitory control, age at injury and time since injury were most predictive of outcome; for social discourse, predictors were injury severity and frontal lobe injury moderated by injury severity. Variability in cognitive outcome after childhood CHI is not random, but appears related to age, time, and biological features of the injury.     

Dissociation of frequency and recency processing from list recall after severe closed head injury in children and adolescents

To investigate judgment of the frequency and recency of events relative to word list recall in children following closed head injury (CHI), 124 children and adolescents, including 79 severe CHI patients (mean age at test = 13.2 years), 27 mild CHI cases (mean age at test = 12.1 years), and 18 uninjured comparison subjects (mean age = 12.8 years) were studied. The mean postinjury interval was 63.6 months for the severe and 46.7 months for the mild CHI groups. The experimental tasks included estimation of the frequency of presentation of words and designs and recency judgment to select the most recently presented of two stimuli on verbal (words) and nonverbal (faces) tasks. To compare frequency and recency judgments to performance on a task which has been shown to be sensitive to CHI severity and age at test, verbal recall was tested using the California Verbal Learning Test-Children's Version. Severity of CHI (group) affected verbal recall across trials and after delays, but had no effect on estimating frequency and isolated effects on judgment of recency. Age was also primarily related to verbal recall. A subgroup of severe CHI patients with frontal lesions was impaired on delayed recall. The results are discussed in relation to previous research on the effects of CHI on processing the frequency and recency of events.     

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.     

Depth of lesion model in children and adolescents with moderate to severe traumatic brain injury: use of SPGR MRI to predict severity and outcome

OBJECTIVES: The utility of a depth of lesion classification using an SPGR MRI sequence in children with moderate to severe traumatic brain injury (TBI) was examined. Clinical and depth of lesion classification measures of TBI severity were used to predict neurological and functional outcome after TBI. METHODS: One hundred and six children, aged 4 to 19, with moderate to severe TBI admitted to a rehabilitation unit had an SPGR MRI sequence obtained 3 months afterTBI. Acquired images were analyzed for location, number, and size of lesions. The Glasgow coma scale (GCS) was the clinical indicator of severity. The deepest lesion present was used for depth of lesion classification. Speed of injury was inferred from the type of injury. The disability rating scale at the time of discharge from the rehabilitation unit (DRS1) and at 1 year follow up (DRS2) were functional outcome measures. RESULTS: The depth of lesion classification was significantly correlated with GCS severity, number of lesions, and both functional measures, DRS1 and DRS2. This result was more robust for time 1, probably due to the greater number of psychosocial factors impacting on functioning at time 2. Lesion volume was not correlated with the depth of lesion model. In multivariate models, depth of lesion was most predictive of DRS1, whereas GCS was most predictive of DRS2. CONCLUSIONS: A depth of lesion classification of TBI severity may have clinical utility in predicting functional outcome in children and adolescents with moderate to severe TBI.     

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.     

Functional memory skills following traumatic brain injury in young children

Traumatic brain injury (TBI) may have a profound impact on a child's ongoing development. Various risk factors have been found to predict outcome, but considerable variability remains unexplained. This study used a prospective, longitudinal design to examine recovery of memory function following TBI within the pre-school period. Forty-four children with TBI were divided according to injury severity (mild, moderate, severe), and compared to age and SES matched healthy controls (n = 26). Children were evaluated acutely and at 12 months post-injury using the Rivermead Behavioural Memory Test for Children. Results failed to show a clear dose-response relationship between injury severity and memory function during the acute phase of recovery. However, this relationship developed over time, with greater memory impairments evident for children with more severe TBI by 12 months post-injury. Children with mild TBI exhibited few memory problems.     

The King's Outcome Scale for Childhood Head Injury and injury severity and outcome measures in children with traumatic brain injury

The aim of this study was to relate discharge King's Outcome Scale for Childhood Head Injury (KOSCHI) category to injury severity and detailed outcome measures obtained in the first year post-traumatic brain injury (TBI). We used a prospective cohort study. Eighty-one children with TBI were studied: 29 had severe, 15 moderate, and 37 mild TBI. The male:female ratio was 1.8:1. The mean age was 11 years 10 months (SD 3.6, range 5-16y). Discharge KOSCHI categories were good (n=34), moderate (n=39), severe (n=6), and unclassifiable (n=2). KOSCHI category correlated strongly with admission Glasgow Coma Score, length of hospital stay, and post-traumatic amnesia. It also correlated significantly with Verbal IQ and Performance IQ (Wechsler); measures of attention; health status (Health Utilities Index [HUI]); health-related quality of life (Pediatric Quality of Life Inventory [PedsQL]); depressive symptoms (Birleson Depression Scale) assessed within 3 months postTBI; and with Verbal IQ, selective attention (map mission), and HUI and PedsQL domains assessed at least 6 months post-TBI discharge. KOSCHI did not correlate with behaviour or executive function. We conclude that the KOSCHI scored at hospital discharge correlates with severity of injury and some cognitive, health status, and HRQL outcomes early after TBI. It is not helpful at predicting later difficulties, or behavioural and emotional problems.     

Educational skills: Long-term outcome and predictors following paediatric traumatic brain injury

Given that reading, spelling and arithmetic skills are acquired through childhood, their development may be compromised following a childhood traumatic brain injury (TBI). The present study examined educational skills (reading accuracy, spelling and arithmetic) at a mean follow-up interval of 6.8 years post-injury in children who had sustained a mild, moderate, or severe TBI at two ages: ‘Young’ (age at injury: 3–7 years, n = 48) and ‘Old’: (age at injury: 8–12 years, n = 36). Comparisons between the young and old TBI groups resulted in inconsistent findings. While a dose-response relationship for severity was evident for the young group, this was not always the case for the old group. Significant predictors of outcome included both severity and acute intellectual function.     

Outcomes following childhood head injury: a population study

OBJECTIVES: To identify outcomes following head injury (HI) among a population of children admitted to one hospital centre and to compare outcomes between different severity groups. METHODS: A postal follow up of children admitted with HI to one National Health Service Trust, between 1992 and 1998, was carried out. Children were aged 5-15 years at injury (mean 9.8), followed up at a mean of 2.2 years post-injury. Parents of 526 injured children (419 mild, 58 moderate, 49 severe) and 45 controls completed questionnaires. Outcomes were assessed using the King's Outcome Scale for Childhood Head Injury (KOSCHI). RESULTS: Frequent behavioural, emotional, memory, and attention problems were reported by one third of the severe group, one quarter of the moderate, and 10-18% of the mild. Personality change since HI was reported for 148 children (28%; 21% mild HI, 46% moderate, 69% severe). There was a significant relationship between injury severity and KOSCHI outcomes. Following the HI, 252 (48%) had moderate disability (43% mild HI, 64% moderate, 69% severe), while 270 (51%) made a good recovery (57% mild HI, 36% moderate, 22% severe). There was a significant association between social deprivation and poor outcome (p = 0.002). Only 30% (158) of children received hospital follow up after the HI. All children with severe disability received appropriate follow up, but 64% of children with moderate disability received none. No evidence was found to suggest a threshold of injury severity below which the risk of late sequelae could be safely discounted. CONCLUSIONS: Children admitted with mild HI may be at risk of poor outcomes, but often do not receive routine hospital follow up. A postal questionnaire combined with the KOSCHI to assess outcomes after HI may be used to identify children who would benefit from clinical assessment. Further research is needed to identify factors that place children with mild HI at risk of late morbidity.     

Cognitive reserve moderates the association between heart failure and cognitive impairment

To investigate judgment of the frequency and recency of events relative to word list recall in children following closed head injury (CHI), 124 children and adolescents, including 79 severe CHI patients (mean age at test = 13.2 years), 27 mild CHI cases (mean age at test = 12.1 years), and 18 uninjured comparison subjects (mean age = 12.8 years) were studied. The mean postinjury interval was 63.6 months for the severe and 46.7 months for the mild CHI groups. The experimental tasks included estimation of the frequency of presentation of words and designs and recency judgment to select the most recently presented of two stimuli on verbal (words) and nonverbal (faces) tasks. To compare frequency and recency judgments to performance on a task which has been shown to be sensitive to CHI severity and age at test, verbal recall was tested using the California Verbal Learning Test-Children's Version. Severity of CHI (group) affected verbal recall across trials and after delays, but had no effect on estimating frequency and isolated effects on judgment of recency. Age was also primarily related to verbal recall. A subgroup of severe CHI patients with frontal lesions was impaired on delayed recall. The results are discussed in relation to previous research on the effects of CHI on processing the frequency and recency of events.     

Social communication in young children with traumatic brain injury: Relations with corpus callosum morphometry

The purpose of the present investigation was to characterize the relations of specific social communication behaviors, including joint attention, gestures, and verbalization, with surface area of midsagittal corpus callosum (CC) subregions in children who sustained traumatic brain injury (TBI) before 7 years of age. Participants sustained mild (n = 10) or moderate–severe (n = 26) noninflicted TBI. The mean age at injury was 33.6 months; mean age at MRI was 44.4 months. The CC was divided into seven subregions. Relative to young children with mild TBI, those with moderate–severe TBI had smaller surface area of the isthmus. A semi-structured sequence of social interactions between the child and an examiner was videotaped and coded for specific social initiation and response behaviors. Social responses were similar across severity groups. Even though the complexity of their language was similar, children with moderate–severe TBI used more gestures than those with mild TBI to initiate social overtures; this may indicate a developmental lag or deficit as the use of gestural communication typically diminishes after age 2. After controlling for age at scan and for total brain volume, the correlation of social interaction response and initiation scores with the midsagittal surface area of the CC regions was examined. For the total group, responding to a social overture using joint attention was significantly and positively correlated with surface area of all regions, except the rostrum. Initiating joint attention was specifically and negatively correlated with surface area of the anterior midbody. Use of gestures to initiate a social interaction correlated significantly and positively with surface area of the anterior and posterior midbody. Social response and initiation behaviors were selectively related to regional callosal surface areas in young children with TBI. Specific brainbehavior relations indicate early regional specialization of anterior and posterior CC for social communication.     

Contralateral MRI abnormalities in candidates for hemispherectomy for refractory epilepsy

Purpose: To assess the impact of contralateral magnetic resonance imaging (MRI) findings on seizure outcome after hemispherectomy for refractory epilepsy. Methods: We retrospectively reviewed 110 children, 0.4–18 (median 5.9) years of age, who underwent hemispherectomy for severe refractory epilepsy at Cleveland Clinic Children’s Hospital. In children with contralateral (as well as ipsilateral) MRI findings appreciated preoperatively, the decision to proceed to surgery was based on other features concordant with the side with the most severe MRI abnormality, including ipsilateral epileptiform discharges, lateralizing seizure semiology, and side of hemiparesis. Results: We retrospectively observed contralateral MRI abnormalities (predominantly small hemisphere, white matter loss or abnormal signal, or sulcation abnormalities) in 81 patients (74%), including 31 of 43 (72%) with malformations of cortical development (MCD), 31 of 42 (73%) with perinatal injury from infarction or hypoxia, and 15 of 25 (60%) with Rasmussen’s encephalitis, Sturge‐Weber syndrome, or posttraumatic encephalomalacia. Among 84 children (76%) with lesions that were congenital or acquired pre‐ or perinatally, 67 (83%) had contralateral MRI abnormalities (p = 0.02). Contralateral findings were subjectively judged to be mild or moderate in 70 (86%). At follow‐up 12–84 (median 24) months after surgery, 79% of patients with contralateral MRI abnormalities were seizure‐free compared to 83% of patients without contralateral MRI findings, with no differences based on etiology group or type or severity of contralateral MRI abnormality. Discussion: MRI abnormalities, usually mild to moderate in severity, were seen in the contralateral hemisphere in the majority of children who underwent hemispherectomy for refractory epilepsy due to various etiologies, especially those that were congenital or early acquired. The contralateral MRI findings, always much less prominent than those in the ipsilateral hemisphere, did not correlate with seizure outcome and may not contraindicate hemispherectomy in otherwise favorable candidates.     

Noninvasive magnetic resonance imaging stratifies injury severity in a rodent model of male juvenile traumatic brain injury

Age and severity are significant predictors of traumatic brain injury (TBI) outcomes in the immature brain. TBI studies have segregated TBI injury into three severity groups: mild, moderate, and severe. While mild TBI is most frequent form in children and adults, there is debate over the indicators used to denote mild injury. Clinically, magnetic resonance imaging (MRI) and computed tomography (CT) are used to diagnose the TBI severity when medically warranted. Herein, we induced mild, moderate, and severe TBI in juvenile rats (jTBI) using the controlled cortical impact model. We characterized the temporal and spatial injury after graded jTBI in vivo using high-field MRI at 0.25 (6 hr), 1 and 3 days post-injury (dpi) with comparative histology. Susceptibility-weighted imaging (SWI) for blood and T2-weighted imaging (T2WI) for edema were quantified over the 0.25–3 dpi. Edema volumes increased linearly with severity at 0.25 dpi that slowly continued to decrease over the 3 dpi. In contrast, blood volumes did not decrease over time. Mild TBI had the least amount of blood visible on SWI. Fluoro-jade B (FJB) staining for cell death confirmed increased cellular death with increasing severity and increased FJB + cells in the corpus callosum (CC). Interestingly, the strongest correlation was observed for cell death and the presence of extravascular blood. A clear understanding of acute brain injury (jTBI) and how blood/edema contribute to mild, moderate, and severe jTBI is needed prior to embarking on therapeutic interventions. Noninvasive imaging should be used in mild jTBI to verify lack of overt injury.     

Multimodality comparison of neuroimaging in pediatric traumatic brain injury

Traumatic brain injury is a common cause of death and disability in children; early neuroimaging has assumed an increasingly important role in evaluating the extent and severity of injury. Several imaging methods were assessed in a study of 40 children with traumatic brain injury: computed tomography (CT), T(2)-weighted magnetic resonance imaging (MRI), fluid-attenuated inversion recovery (FLAIR) MRI, and susceptibility-weighted imaging (SWI) MRI to determine which were most valuable in predicting 6-12 month outcomes as classified by the Pediatric Cerebral Performance Category Scale score. Patients were subdivided into three groups: (1) normal, (2) mild disability, and (3) moderate/severe disability/persistent vegetative state. T(2), FLAIR, and SWI showed no significant difference in lesion volume between normal and mild outcome groups, but did indicate significant differences between normal and poor and between mild and poor outcome groups. Computed tomography revealed no significant differences in lesion volume between any groups. The findings suggest that T(2), FLAIR, and SWI MRI sequences provide a more accurate assessment of injury severity and detection of outcome-influencing lesions than does CT in pediatric traumatic brain injury patients. Although CT was inconsistent at lesion detection/outcome prediction, it remains an essential part of the acute traumatic brain injury work-up to assess the need for neurosurgic intervention.     

Spectrum of movement disorders in encephalitis

To study the frequency and type of movement disorders and correlate these with MRI findings and outcome. Consecutive patients having encephalitis with movement disorders were included. The encephalitides were categorized into Japanese encephalitis (JE), herpes simplex, dengue, mumps, measles and nonspecific, depending on respective ELISA or CSF PCR. The movement disorders were recorded and severity was graded into mild, moderate, severe and markedly severe. Cranial MRI was done on a 1.5 T scanner acquiring T1, T2 and FLAIR sequence, and the location of MRI changes was noted. Outcome was defined at 6 months on the basis of functional status into complete, partial or poor. The type and severity of movement disorders and their relation to outcome was evaluated. Seventy-four out of 209 encephalitis patients had movement disorders; 67.6% of the patients had JE, 51.2% nonspecific and 11.3% dengue encephalitis. Their median age was 19 years and 16 were females. Parkinsonian features were present in 36, dystonia in six and both in 32 patients. The severity of movement disorders ranged between 2 and 4 (scale: none = 0, mild = 1, moderate = 2, severe = 3, markedly severe = 4). Movement disorders were common in males (P = 0.0001), and more frequent in JE (P = 0.03) and those having substantia nigra involvement on MRI (P = 0.03). Dystonia was associated with worse outcome than parkinsonian features only (P = 0.01). Movement disorders are common and severe in JE and are related to typical anatomical involvement.     

Neuroanatomic correlates of CVLT-C performance following pediatric traumatic brain injury.

Traumatic brain injury (TBI) frequently results in memory problems, and the degree of memory impairment is related to injury severity and is commonly associated with lesions in frontal and temporal brain areas. This study examined the relationship among injury severity, brain lesions, and memory in children with moderate to severe TBI using Donders' (1999) 5-factor model of performance on the California Verbal Learning Test-Children's Version (CVLT-C). Seventy-six children underwent magnetic resonance imaging (MRI) scans 3 months post-TBI and testing 1 year post-TBI. Results showed injury severity (Glasgow Coma Scale) was not predictive of performance on 4 of the 5 factors. Volume of frontal and/or temporal brain lesions was significantly predictive of performance on 3 of the 5 factors. Unexpectedly, lesion volume outside these areas (extra-frontotemporal) was predictive of performance on all 5 factors. In contrast, Verbal IQ at 1 year was most strongly associated with preinjury factors (socioeconomic status and special education involvement), although extra-frontotemporal lesions also contributed to the variability in this measure. Results suggest that in children with moderate to severe TBI, extra-frontal/temporal lesions are predictive of memory outcome 1 year postinjury above and beyond initial severity or frontal/temporal contusions. This finding may relate to widespread diffuse axonal injury, which potentially disconnects brain circuits mediating memory following moderate to severe TBI.     

Identifying factors contributing to child and family outcome 30 months after traumatic brain injury in children

OBJECTIVE: To examine the contributions of injury severity, physical and cognitive disability, child and family function to outcome 30 months after traumatic brain injury (TBI) in children. DESIGN: A prospective, longitudinal, between group design, comparing function before and after injury across three levels of injury severity. SUBJECTS: One hundred and fifty children, 3.0-12.11 years old, admitted to hospital with a diagnosis of TBI. The sample was divided according to injury severity: mild (n = 42), moderate (n = 70), severe (n = 38). Children with a history of neurological, developmental, and psychiatric disorders were excluded from participation. MAIN OUTCOME MEASURES: Post injury physical function, cognitive ability (incorporating intellect, memory, and attention), behavioural and family functioning, and level of family burden. RESULTS: A dose-response relation was identified for injury severity and physical and cognitive outcome, with significant recovery documented from acute to six months after TBI. Behavioural functioning was not related to injury severity, and where problems were identified, little recovery was noted over time. Family functioning remained unchanged from preinjury to post injury assessments. The level of family burden was high at both six and 30 months after injury, and was predicted by injury severity, functional impairment, and post injury child behavioural disturbance. CONCLUSIONS: These results suggest ongoing problems for the child and significant family burden 30 months after TBI. The nature and severity of the physical and cognitive problems are closely related to injury severity, with child and family function predicted by psychosocial and premorbid factors.     

Cognitive sequelae of diffuse axonal injury

BACKGROUND: The results of recent studies on cognitive disability after traumatic brain injury-associated diffuse axonal injury (DAI) are inconsistent. In these studies, the diagnosis of DAI relied on cranial computed tomography. OBJECTIVE: To further clarify the extent and severity of a possibly DAI-associated cognitive impairment by the use of magnetic resonance imaging (MRI) and detailed neuropsychological testing. DESIGN AND PARTICIPANTS: From a databank of 299 patients with traumatic brain injury, 18 patients (age range, 17-50 years; median initial Glasgow Coma Scale score, 5) who showed an MRI lesion pattern compatible with pure DAI were identified. All of the patients had undergone MRI on a 3-T system. Pure DAI was defined by the findings of traumatic microbleeds on T2*-weighted gradient-echo images in the absence of otherwise traumatic or nontraumatic MRI abnormalities. MAIN OUTCOME MEASURES: Neuropsychological performance in the categories of attention and psychomotor speed, executive functions, spans, learning and memory, and intelligence 4 to 55 months (median, 9 months) after traumatic brain injury. RESULTS: All of the patients showed impairments of 1 or more cognitive subfunctions, and no cognitive domain was fundamentally spared. Memory and executive dysfunctions were most frequent, the former reaching a moderate to severe degree in half of the patients. In comparison, deficits of attention, executive functions, and short-term memory were mostly mild. Correlations between the amount of traumatic microbleeds and specific or global cognitive performance were absent. CONCLUSIONS: An MRI lesion pattern compatible with isolated DAI is associated with persistent cognitive impairment. The traumatic microbleed load is no sufficient parameter for the assessment of DAI severity or functional outcome.