Abstract
Primary objective: This study examined long-term alterations in white matter microstructure following TBI in adolescence using diffusion tensor imaging (DTI). It was hypothesized that white matter integrity would be compromised in adolescents with TBI and would correlate with measures of executive functioning and cognitive abilities.
Research design: This study employed whole-brain, voxel-wise, statistical comparison of DTI indices in youth of 12–17 years old (mean = 15.06) with TBI vs an age- and gender-matched cohort (mean age = 15.37).
Methods and procedures: This study scanned 17 adolescents with complicated-mild-to-severe TBI, 1–3 years after injury, and 13 healthy adolescents. Tract-Based Spatial Statistics (TBSS) was employed for DTI analysis.
Main outcomes and results: Overall diffusivity elevations were found in the TBI group with increases in axial diffusivity in the right hemisphere. White matter integrity was associated with word reading, planning and processing times in the TBI group, but not healthy controls.
Conclusions: The detected abnormalities in axial diffusivity may reflect neuronal regeneration and cerebral reorganization after injury. These findings provide tentative evidence of persistent white matter alteration following TBI in adolescence. Associations of DTI indices with cognitive performance following TBI provide tentative support for links between white matter integrity and performance post-TBI.
Abbreviations: White matter region abbreviations | ||
ACR | = | anterior corona radiate |
ALIC | = | anterior limb of the internal capsule |
CP | = | cerebral peduncle |
Cing | = | Cingulum |
ExCAP | = | external capsule |
gCC | = | bCC, sCC, genu, body, splenium of the corpus callosum |
PCR | = | right posterior corona radiate |
PLIC | = | posterior limb of the internal capsule |
PTR | = | posterior thalamic radiation |
RetroIC | = | retrolenticular part of the internal capsule |
SCR | = | superior corona radiata |
SS | = | sagittal stratum |
TAP | = | tapetum. These regions in the left and right hemispheres were denoted using l or r prefixes, respectively. e.g. lPLIC, left posterior limb of the internal capsule. White matter tract abbreviations: ATR, anterior thalamic radiation |
CST | = | cortico-spinal tract |
Fmin | = | forceps minor |
IFOF | = | inferior fronto-occipital fasciculus |
SLF | = | superior longitudinal fasciculus |
UF | = | uncinate fasciculus. These tracts in the left and right hemispheres were denoted using l or r prefixes, e.g. lSLF, left superior longitudinal fasciculus. Magnetic Resonance Imaging abbreviations: EPI, Echo Planar Imaging |
FSE | = | Fast Spin Echo |
GRE | = | Gradient Echo |
MPRAGE | = | Magnetization Prepared Rapid Gradient Echo |
TE | = | echo time |
TI | = | inversion time |
TR | = | repetition time. Neuropsychological tests: PPVT, Peabody Picture Vocabulary Test Version 4 |
WRAT | = | Wide Range Achievement Test 4th Edition word reading sub-test |
DKEFS | = | Delis-Kaplan Executive Function System |
Tower | = | Tower Total Achievement Score |
ISvCb | = | Interference/Switching minus colour baseline |
WISC | = | Wechsler Intelligence Scale for Children 4th Edition |
PSI | = | Processing Speed Index |
WMI | = | Working Memory Index |
BRIEF | = | Behaviour Rating Inventory of Executive Function |
GEC | = | Global Executive Composite |
SR | = | Self-Report. Other abbreviations: CT, Computed Tomography |
FEW | = | Family-Wise Error |
GCS | = | Glasgow Coma Score |
ICBM | = | International Consortium of Brain Mapping |
JHU | = | John Hopkins University |
MNI | = | Montreal Neurological Institute |
TBSS | = | Tract-Based Spatial Statistics |
TFCE | = | Threshold-Free Cluster Enhancement. |
Abbreviations: White matter region abbreviations | ||
ACR | = | anterior corona radiate |
ALIC | = | anterior limb of the internal capsule |
CP | = | cerebral peduncle |
Cing | = | Cingulum |
ExCAP | = | external capsule |
gCC | = | bCC, sCC, genu, body, splenium of the corpus callosum |
PCR | = | right posterior corona radiate |
PLIC | = | posterior limb of the internal capsule |
PTR | = | posterior thalamic radiation |
RetroIC | = | retrolenticular part of the internal capsule |
SCR | = | superior corona radiata |
SS | = | sagittal stratum |
TAP | = | tapetum. These regions in the left and right hemispheres were denoted using l or r prefixes, respectively. e.g. lPLIC, left posterior limb of the internal capsule. White matter tract abbreviations: ATR, anterior thalamic radiation |
CST | = | cortico-spinal tract |
Fmin | = | forceps minor |
IFOF | = | inferior fronto-occipital fasciculus |
SLF | = | superior longitudinal fasciculus |
UF | = | uncinate fasciculus. These tracts in the left and right hemispheres were denoted using l or r prefixes, e.g. lSLF, left superior longitudinal fasciculus. Magnetic Resonance Imaging abbreviations: EPI, Echo Planar Imaging |
FSE | = | Fast Spin Echo |
GRE | = | Gradient Echo |
MPRAGE | = | Magnetization Prepared Rapid Gradient Echo |
TE | = | echo time |
TI | = | inversion time |
TR | = | repetition time. Neuropsychological tests: PPVT, Peabody Picture Vocabulary Test Version 4 |
WRAT | = | Wide Range Achievement Test 4th Edition word reading sub-test |
DKEFS | = | Delis-Kaplan Executive Function System |
Tower | = | Tower Total Achievement Score |
ISvCb | = | Interference/Switching minus colour baseline |
WISC | = | Wechsler Intelligence Scale for Children 4th Edition |
PSI | = | Processing Speed Index |
WMI | = | Working Memory Index |
BRIEF | = | Behaviour Rating Inventory of Executive Function |
GEC | = | Global Executive Composite |
SR | = | Self-Report. Other abbreviations: CT, Computed Tomography |
FEW | = | Family-Wise Error |
GCS | = | Glasgow Coma Score |
ICBM | = | International Consortium of Brain Mapping |
JHU | = | John Hopkins University |
MNI | = | Montreal Neurological Institute |
TBSS | = | Tract-Based Spatial Statistics |
TFCE | = | Threshold-Free Cluster Enhancement. |