Scale and pattern of atrophy in the chronic stages of moderate-severe TBI

Background. Moderate-severe traumatic brain injury (TBI) is increasingly being understood as a progressive disorder, with growing evidence of reduced brain volume and white matter integrity as well as lesion expansion in the chronic phases of injury. The scale of these losses has yet to be investiga...

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Main Authors: Robin E.A. Green, Brenda eColella, Jerome Joseph Maller, Mark eBayley, Joanna eGlazer, David R Mikulis
Format: Article
Language:English
Published: Frontiers Media S.A. 2014-03-01
Series:Frontiers in Human Neuroscience
Subjects:
MRI
Online Access:http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00067/full
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spelling doaj-36d037fecfa6445fa24d17d42a1d39512020-11-25T03:29:11ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612014-03-01810.3389/fnhum.2014.0006743268Scale and pattern of atrophy in the chronic stages of moderate-severe TBIRobin E.A. Green0Brenda eColella1Jerome Joseph Maller2Mark eBayley3Joanna eGlazer4David R Mikulis5Toronto Rehabilitation Institute / University of TorontoToronto Rehabilitation Institute / University of TorontoMonash Alfred Psychiatry Research Centre, Alfred HospitalToronto Rehabilitation InsituteToronto Rehabilitation Institute / University of TorontoUniversity of TorontoBackground. Moderate-severe traumatic brain injury (TBI) is increasingly being understood as a progressive disorder, with growing evidence of reduced brain volume and white matter integrity as well as lesion expansion in the chronic phases of injury. The scale of these losses has yet to be investigated, and pattern of change across structures has received limited attention. Objectives. To measure (1) proportion of moderate-severe TBI patients with atrophy from 5 to 20 mos post-injury, and (2) relative vulnerability to and consistency of volume loss in structures with vulnerability to acute TBI. Methods. 56 patients (mean GCS = 6.1) underwent MRI 5 and 20 mos post-injury; 12 healthy controls underwent MRI twice. Mean monthly percent change was computed for whole brain (ventricle-to-brain ratio; VBR), corpus callosum (CC), and right and left hippocampi (HPC). Results. (1) Using a threshold of 2 z-scores below controls, 96% of patients declined on at least one region; 75% declined in at least 3/4. (2) There were no significant differences in proportion of patients showing decline across structures. For those showing decline in VBR, there was a significant association with both the CC and the right HPC (P < .05 for both comparisons). There were significant associations between those showing decline in (i) right and left HPC (P < .05); (ii) genu, body and splenium of the CC, and (iii) head and tail of the right HPC (P< .05 all sub-structure comparisons). Conclusions. Atrophy in chronic moderate-severe TBI is robust, and the CC, right HPC and left HPC appear equally vulnerable. Significant associations between the right and left HPC, and within substructures of the CC and right HPC raise the possibility of common mechanisms affecting associated regions, or spread of degeneration across structures (e.g., transneuronal degeneration). As atrophy has been associated with poorer functional outcomes, offsetting atrophy should be a target of rehabilitation interventions.http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00067/fullAtrophyMRITraumatic Brain Injurydegenerationprogressionchronic
collection DOAJ
language English
format Article
sources DOAJ
author Robin E.A. Green
Brenda eColella
Jerome Joseph Maller
Mark eBayley
Joanna eGlazer
David R Mikulis
spellingShingle Robin E.A. Green
Brenda eColella
Jerome Joseph Maller
Mark eBayley
Joanna eGlazer
David R Mikulis
Scale and pattern of atrophy in the chronic stages of moderate-severe TBI
Frontiers in Human Neuroscience
Atrophy
MRI
Traumatic Brain Injury
degeneration
progression
chronic
author_facet Robin E.A. Green
Brenda eColella
Jerome Joseph Maller
Mark eBayley
Joanna eGlazer
David R Mikulis
author_sort Robin E.A. Green
title Scale and pattern of atrophy in the chronic stages of moderate-severe TBI
title_short Scale and pattern of atrophy in the chronic stages of moderate-severe TBI
title_full Scale and pattern of atrophy in the chronic stages of moderate-severe TBI
title_fullStr Scale and pattern of atrophy in the chronic stages of moderate-severe TBI
title_full_unstemmed Scale and pattern of atrophy in the chronic stages of moderate-severe TBI
title_sort scale and pattern of atrophy in the chronic stages of moderate-severe tbi
publisher Frontiers Media S.A.
series Frontiers in Human Neuroscience
issn 1662-5161
publishDate 2014-03-01
description Background. Moderate-severe traumatic brain injury (TBI) is increasingly being understood as a progressive disorder, with growing evidence of reduced brain volume and white matter integrity as well as lesion expansion in the chronic phases of injury. The scale of these losses has yet to be investigated, and pattern of change across structures has received limited attention. Objectives. To measure (1) proportion of moderate-severe TBI patients with atrophy from 5 to 20 mos post-injury, and (2) relative vulnerability to and consistency of volume loss in structures with vulnerability to acute TBI. Methods. 56 patients (mean GCS = 6.1) underwent MRI 5 and 20 mos post-injury; 12 healthy controls underwent MRI twice. Mean monthly percent change was computed for whole brain (ventricle-to-brain ratio; VBR), corpus callosum (CC), and right and left hippocampi (HPC). Results. (1) Using a threshold of 2 z-scores below controls, 96% of patients declined on at least one region; 75% declined in at least 3/4. (2) There were no significant differences in proportion of patients showing decline across structures. For those showing decline in VBR, there was a significant association with both the CC and the right HPC (P < .05 for both comparisons). There were significant associations between those showing decline in (i) right and left HPC (P < .05); (ii) genu, body and splenium of the CC, and (iii) head and tail of the right HPC (P< .05 all sub-structure comparisons). Conclusions. Atrophy in chronic moderate-severe TBI is robust, and the CC, right HPC and left HPC appear equally vulnerable. Significant associations between the right and left HPC, and within substructures of the CC and right HPC raise the possibility of common mechanisms affecting associated regions, or spread of degeneration across structures (e.g., transneuronal degeneration). As atrophy has been associated with poorer functional outcomes, offsetting atrophy should be a target of rehabilitation interventions.
topic Atrophy
MRI
Traumatic Brain Injury
degeneration
progression
chronic
url http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00067/full
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