title: Structural white matter differences underlying heterogeneous learning abilities after TBI.
abstract: The existence of learning deficits after traumatic brain injury (TBI) is generally accepted; however, our understanding of the structural brain mechanisms underlying learning impairment after TBI is limited. Furthermore, our understanding of learning after TBI is often at risk for overgeneralization, as research often overlooks within sample heterogeneity in learning abilities. The present study examined differences in white matter integrity in a sample of adults with moderate to severe TBI who differed in learning abilities. Adults with moderate to severe TBI were grouped into learners and non-learners based upon achievement of the learning criterion of the open-trial Selective Reminding Test (SRT). Diffusion tensor imaging (DTI) was used to identify white matter differences between the learners and non-learners. Adults with TBI who were able to meet the learning criterion had greater white matter integrity (as indicated by higher fractional anisotropy [FA] values) in the right anterior thalamic radiation, forceps minor, inferior fronto-occipital fasciculus, and forceps minor than non-learners. The results of the study suggest that differences in white matter integrity may explain the observed heterogeneity in learning ability after moderate to severe TBI. This also supports emerging evidence for the involvement of the thalamus in higher order cognition, and the role of thalamo-cortical tracts in connecting functional networks associated with learning.
authors.affiliation: Traumatic Brain Injury Research, Kessler Foundation, West Orange, NJ, USA. kchiou@kesslerfoundation.org.|Department of Physical Medicine & Rehabilitation, Rutgers-New Jersey Medical School, Newark, NJ, USA. kchiou@kesslerfoundation.org.
authors.forename: Kathy S
authors.initials: KS
authors.lastname: Chiou
authors.affiliation: Neuropsychology and Neuroscience Research, Kessler Foundation, West Orange, NJ, USA.|Department of Physical Medicine & Rehabilitation, Rutgers-New Jersey Medical School, Newark, NJ, USA.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Genova
authors.affiliation: Traumatic Brain Injury Research, Kessler Foundation, West Orange, NJ, USA.|Neuropsychology and Neuroscience Research, Kessler Foundation, West Orange, NJ, USA.|Department of Physical Medicine & Rehabilitation, Rutgers-New Jersey Medical School, Newark, NJ, USA.
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Chiaravalloti
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging; D000070642:Brain Injuries, Traumatic / Q000150:complications / Q000000981:diagnostic imaging* / Q000523:psychology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007858:Learning; D007859:Learning Disabilities / Q000000981:diagnostic imaging / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D066127:White Matter / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Diffusion tensor imaging; Memory; Traumatic brain injury; Verbal learning