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Retrospective self-report is typically used for diagnosing previous pediatric traumatic brain injury (TBI). A new semi-structured interview instrument (New Mexico Assessment of Pediatric TBI; NewMAP TBI) investigated test–retest reliability for TBI characteristics in both the TBI that qualified for study inclusion and for lifetime history of TBI.
One-hundred and eight-four mTBI (aged 8–18), 156 matched healthy controls (HC), and their parents completed the NewMAP TBI within 11 days (subacute; SA) and 4 months (early chronic; EC) of injury, with a subset returning at 1 year (late chronic; LC).
The test–retest reliability of common TBI characteristics [loss of consciousness (LOC), post-traumatic amnesia (PTA), retrograde amnesia, confusion/disorientation] and post-concussion symptoms (PCS) were examined across study visits. Aside from PTA, binary reporting (present/absent) for all TBI characteristics exhibited acceptable (≥0.60) test–retest reliability for both Qualifying and Remote TBIs across all three visits. In contrast, reliability for continuous data (exact duration) was generally unacceptable, with LOC and PCS meeting acceptable criteria at only half of the assessments. Transforming continuous self-report ratings into discrete categories based on injury severity resulted in acceptable reliability. Reliability was not strongly affected by the parent completing the NewMAP TBI.
Categorical reporting of TBI characteristics in children and adolescents can aid clinicians in retrospectively obtaining reliable estimates of TBI severity up to a year post-injury. However, test–retest reliability is strongly impacted by the initial data distribution, selected statistical methods, and potentially by patient difficulty in distinguishing among conceptually similar medical concepts (i.e., PTA vs. confusion).
This study aimed to examine the predictors of cognitive performance in patients with pediatric mild traumatic brain injury (pmTBI) and to determine whether group differences in cognitive performance on a computerized test battery could be observed between pmTBI patients and healthy controls (HC) in the sub-acute (SA) and the early chronic (EC) phases of injury.
203 pmTBI patients recruited from emergency settings and 159 age- and sex-matched HC aged 8–18 rated their ongoing post-concussive symptoms (PCS) on the Post-Concussion Symptom Inventory and completed the Cogstate brief battery in the SA (1–11 days) phase of injury. A subset (156 pmTBI patients; 144 HC) completed testing in the EC (~4 months) phase.
Within the SA phase, a group difference was only observed for the visual learning task (One-Card Learning), with pmTBI patients being less accurate relative to HC. Follow-up analyses indicated higher ongoing PCS and higher 5P clinical risk scores were significant predictors of lower One-Card Learning accuracy within SA phase, while premorbid variables (estimates of intellectual functioning, parental education, and presence of learning disabilities or attention-deficit/hyperactivity disorder) were not.
The absence of group differences at EC phase is supportive of cognitive recovery by 4 months post-injury. While the severity of ongoing PCS and the 5P score were better overall predictors of cognitive performance on the Cogstate at SA relative to premorbid variables, the full regression model explained only 4.1% of the variance, highlighting the need for future work on predictors of cognitive outcomes.
As the authors of this chapter declare early on, it is hard to overestimate the centrality of functional neuroimaging to the 21st-century success in overthrowing the 20th-century error that concussions are transient. Preliminary evidence demonstrates that so-called "mild" traumatic brain injuries routinely cause brain changes detectible up to 60 months later. The authors are world-renowned authorities on this subject, with access to the most advanced extant technologies and empirical observations. This chapter explains the methodologies, reviews the findings to date, and predicts the forthcoming explosion of data gathering that will surely expand the knowledge base and enhance (or perhaps upend) both the theoretical foundations of concussion research and the prospects for practical human benefits.
Multibeam bathymetry and 3.5-kHz sub-bottom profiler data collected from the US icebreaker Healy in 2003 provide convincing evidence for grounded ice on the Chukchi Borderland off the northern Alaskan margin, Arctic Ocean. The data show parallel, glacially induced seafloor scours, or grooves, and intervening ridges that reach widths of 1000 m (rim to rim) and as much as 40 m relief. Following previous authors, we refer to these features as “megascale glacial lineations (MSGLs).” Additional support for ice grounding is apparent from stratigraphic unconformities, interpreted to have been caused by ice-induced erosion. Most likely, the observed sea-floor features represent evidence for massive ice-shelf grounding. The general ESE/WNW direction of the MSGLs, together with sediment, evidently bulldozed off the Chukchi Plateau, that is mapped on the western (Siberian) side of the plateau, suggests ice flow from the Canada Basin side of Chukchi Borderland. Two separate generations of glacially derived MSGLs are identified on the Chukchi Borderland from the Healy geophysical data. The deepest and oldest extensive MSGLs appear to be draped by sediments less than 5 m thick, whereas no sediment drape can be distinguished within the resolution of the sub-bottom profiles on the younger generation.
Objectives: Blast explosions are the most frequent mechanism of traumatic brain injury (TBI) in recent wars, but little is known about their long-term effects. Methods: Functional connectivity (FC) was measured in 17 veterans an average of 5.46 years after their most serious blast related TBI, and in 15 demographically similar veterans without TBI or blast exposure. Subcortical FC was measured in bilateral caudate, putamen, and globus pallidus. The default mode and fronto-parietal networks were also investigated. Results: In subcortical regions, between-groups t tests revealed altered FC from the right putamen and right globus pallidus. However, following analysis of covariance (ANCOVA) with age, depression (Center for Epidemiologic Studies Depression Scale), and posttraumatic stress disorder symptom (PTSD Checklist – Civilian version) measures, significant findings remained only for the right globus pallidus with anticorrelation in bilateral temporal occipital fusiform cortex, occipital fusiform gyrus, lingual gyrus, and cerebellum, as well as the right occipital pole. No group differences were found for the default mode network. Although reduced FC was found in the fronto-parietal network in the TBI group, between-group differences were nonsignificant after the ANCOVA. Conclusions: FC of the globus pallidus is altered years after exposure to blast related TBI. Future studies are necessary to explore the trajectory of changes in FC in subcortical regions after blast TBI, the effects of isolated versus repetitive blast-related TBI, and the relation to long-term outcomes in veterans. (JINS, 2016, 22, 631–642)
Objectives: One of the most prominent features of schizophrenia is relatively lower general cognitive ability (GCA). An emerging approach to understanding the roots of variation in GCA relies on network properties of the brain. In this multi-center study, we determined global characteristics of brain networks using graph theory and related these to GCA in healthy controls and individuals with schizophrenia. Methods: Participants (N=116 controls, 80 patients with schizophrenia) were recruited from four sites. GCA was represented by the first principal component of a large battery of neurocognitive tests. Graph metrics were derived from diffusion-weighted imaging. Results: The global metrics of longer characteristic path length and reduced overall connectivity predicted lower GCA across groups, and group differences were noted for both variables. Measures of clustering, efficiency, and modularity did not differ across groups or predict GCA. Follow-up analyses investigated three topological types of connectivity—connections among high degree “rich club” nodes, “feeder” connections to these rich club nodes, and “local” connections not involving the rich club. Rich club and local connectivity predicted performance across groups. In a subsample (N=101 controls, 56 patients), a genetic measure reflecting mutation load, based on rare copy number deletions, was associated with longer characteristic path length. Conclusions: Results highlight the importance of characteristic path lengths and rich club connectivity for GCA and provide no evidence for group differences in the relationships between graph metrics and GCA. (JINS, 2016, 22, 240–249)
Studies have produced conflicting evidence regarding whether cognitive
control deficits in patients with schizophrenia result from dysfunction
within the cognitive control network (CCN; top-down) and/or unisensory
To investigate CCN and sensory cortex involvement during multisensory
cognitive control in patients with schizophrenia.
Patients with schizophrenia and healthy controls underwent functional
magnetic resonance imaging while performing a multisensory Stroop task
involving auditory and visual distracters.
Patients with schizophrenia exhibited an overall pattern of response
slowing, and these behavioural deficits were associated with a pattern of
patient hyperactivation within auditory, sensorimotor and posterior
parietal cortex. In contrast, there were no group differences in
functional activation within prefrontal nodes of the CCN, with small
effect sizes observed (incongruent–congruent trials). Patients with
schizophrenia also failed to upregulate auditory cortex with concomitant
increased attentional demands.
Results suggest a prominent role for dysfunction within auditory,
sensorimotor and parietal areas relative to prefrontal CCN nodes during
multisensory cognitive control.
Outcome of moderate to severe traumatic brain injury (TBI) includes impaired emotion regulation. Emotion regulation has been associated with amygdala and rostral anterior cingulate (rACC). However, functional connectivity between the two structures after injury has not been reported. A preliminary examination of functional connectivity of rACC and right amygdala was conducted in adolescents 2 to 3 years after moderate to severe TBI and in typically developing (TD) control adolescents, with the hypothesis that the TBI adolescents would demonstrate altered functional connectivity in the two regions. Functional connectivity was determined by correlating fluctuations in the blood oxygen level dependent (BOLD) signal of the rACC and right amygdala with that of other brain regions. In the TBI adolescents, the rACC was found to be significantly less functionally connected to medial prefrontal cortices and to right temporal regions near the amygdala (height threshold T = 2.5, cluster level p < .05, FDR corrected), while the right amygdala showed a trend in reduced functional connectivity with the rACC (height threshold T = 2.5, cluster level p = .06, FDR corrected). Data suggest disrupted functional connectivity in emotion regulation regions. Limitations include small sample sizes. Studies with larger sample sizes are necessary to characterize the persistent neural damage resulting from moderate to severe TBI during development. (JINS, 2013, 19, 1–14)
Previous studies of schizophrenia have suggested a linkage between neuropsychological (NP) deficits and hippocampus abnormality. The relationship between hippocampus volume and NP functioning was investigated in 24 patients with chronic schizophrenia and 24 matched healthy controls. Overall intracranial, white and gray matter, and anterior (AH) and posterior (PH) hippocampus volumes were assessed from magnetic resonance images (MRI). NP domains of IQ, attention, and executive function were also evaluated with respect to volumetric measures. It was hypothesized that AH and PH volumes and episodic memory scores would be positively associated in controls and that the schizophrenia group would depart from this normative pattern. NP functioning was impaired overall and AH volume was smaller in the schizophrenia group. In the controls, the hippocampus–memory relationships involved AH and PH, and correlations were significant for verbal memory measures. In the schizophrenia group, positive correlations were constrained to PH. Negative correlations emerged between AH and verbal and visual memory measures. For both groups, cortical volume negatively correlated with age, but a negative correlation between age and hippocampus volume was found only in the schizophrenia group. In this sample of adults with schizophrenia, atypical relationships between regional hippocampus volumes and episodic memory ability were found, as was an atypical negative association between hippocampus volume and age. (JINS, 2009, 15, 182–195.)
Differing degrees of head motion have long been recognized as a
potential confound in functional neuroimaging studies comparing
neuropsychiatric populations to healthy normal volunteers, and studies
often cite excessive head motion as a possible reason for the different
patterns of functional activation frequently observed between groups. We
empirically tested the degree of head motion in 16 patients with chronic
schizophrenia and 16, age- and education-matched controls during the
acquisition of functional magnetic resonance imaging data. We examined the
degree of motion across three different indices (total motion, relative
motion, task-correlated motion) during a complex attentional task and the
effect of entering the motion parameters as additional regressors in a
general linear model analysis. Results indicate that individuals with
schizophrenia did not exhibit more task-correlated or total motion
compared with controls. Moreover, the residual error term from the general
linear model analysis was similar for both groups of subjects. In
conclusion, current results suggest that stable patients with
schizophrenia are capable of controlling head motion compared with matched
normal controls. However, a direct comparison of the motion parameters is
an essential step for any quality assurance protocol to determine whether
additional corrective techniques need to be implemented. (JINS,
2007, 13, 839–845.)
Previous neuroimaging studies of the Stroop task have postulated
that the anterior cingulate cortex (ACC) plays a critical role
in resolution of the Stroop interference condition. However,
activation of the ACC is not invariably seen and appears to
depend on a variety of methodological factors, including the
degree of response conflict and response expectancies. The present
functional MRI study was designed to identify those brain areas
critically involved in the interference condition. Healthy subjects
underwent a blocked-trial design fMRI experiment while responding
to 1 of 3 stimulus conditions: (1) incongruent color words,
(2) congruent color words, and (3) color-neutral words. Subjects
responded to the printed color of the word via a manual
response. Compared to the congruent and neutral conditions,
the incongruent condition produced significant activation within
the left inferior precentral sulcus (IpreCS) located on the
border between the inferior frontal gyrus, pars opercularis
(BA 44) and the ventral premotor region (BA 6). Significant
deactivations in the rostral component of the ACC and the posterior
cingulate gyrus were also observed. Selective activation of
the left IpreCS is compatible with findings from previous
neuroimaging, lesion, electrophysiological, and behavioral studies
and is presumably related to the mediation of competing
articulatory demands during the interference condition.
(JINS, 2002, 8, 735–742.)
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