Anatomical predictors of aphasia recovery: A tractography study of bilateral perisylvian language networks
Brain. 2014-06-19; 137(7): 2027-2039
DOI: 10.1093/brain/awu113
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1. Brain. 2014 Jul;137(Pt 7):2027-39. doi: 10.1093/brain/awu113.
Anatomical predictors of aphasia recovery: a tractography study of bilateral
perisylvian language networks.
Forkel SJ(1), Thiebaut de Schotten M(2), Dell’Acqua F(3), Kalra L(4), Murphy
DG(5), Williams SC(3), Catani M(6).
Author information:
(1)1 Research Department of Clinical, Educational, and Health Psychology
(RDCEHP), Division of Psychology and Language Sciences, Faculty of Brain
Sciences, University College London, UK2 Natbrainlab, Department of Neuroimaging,
Institute of Psychiatry, King’s College London, UK
.
(2)3 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences,
Institute of Psychiatry, King’s College London, London, UK4 Inserm U1127;
UPMC-Paris6, UMR_S 1127; CNRS UMR 7225, Centre de Recherche de l’Institut du
Cerveau et de la Moelle épinière, Groupe Hospitalier Pitié-Salpêtrière, 75013
Paris, France.
(3)2 Natbrainlab, Department of Neuroimaging, Institute of Psychiatry, King’s
College London, UK5 NIHR Biomedical Research Centre for Mental Health at South
London and Maudsley NHS Foundation Trust and King’s College London, London, UK.
(4)6 Department of Clinical Neuroscience, Institute of Psychiatry, King’s College
London, London, UK.
(5)7 Sackler Institute for Translational Neurodevelopment and Department of
Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King’s College
London, UK.
(6)3 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences,
Institute of Psychiatry, King’s College London, London, UK
.
Stroke-induced aphasia is associated with adverse effects on quality of life and
the ability to return to work. For patients and clinicians the possibility of
relying on valid predictors of recovery is an important asset in the clinical
management of stroke-related impairment. Age, level of education, type and
severity of initial symptoms are established predictors of recovery. However,
anatomical predictors are still poorly understood. In this prospective
longitudinal study, we intended to assess anatomical predictors of recovery
derived from diffusion tractography of the perisylvian language networks. Our
study focused on the arcuate fasciculus, a language pathway composed of three
segments connecting Wernicke’s to Broca’s region (i.e. long segment), Wernicke’s
to Geschwind’s region (i.e. posterior segment) and Broca’s to Geschwind’s region
(i.e. anterior segment). In our study we were particularly interested in
understanding how lateralization of the arcuate fasciculus impacts on severity of
symptoms and their recovery. Sixteen patients (10 males; mean age 60 ± 17 years,
range 28-87 years) underwent post stroke language assessment with the Revised
Western Aphasia Battery and neuroimaging scanning within a fortnight from
symptoms onset. Language assessment was repeated at 6 months. Backward
elimination analysis identified a subset of predictor variables (age, sex, lesion
size) to be introduced to further regression analyses. A hierarchical regression
was conducted with the longitudinal aphasia severity as the dependent variable.
The first model included the subset of variables as previously defined. The
second model additionally introduced the left and right arcuate fasciculus
(separate analysis for each segment). Lesion size was identified as the only
independent predictor of longitudinal aphasia severity in the left hemisphere
[beta = -0.630, t(-3.129), P = 0.011]. For the right hemisphere, age [beta =
-0.678, t(-3.087), P = 0.010] and volume of the long segment of the arcuate
fasciculus [beta = 0.730, t(2.732), P = 0.020] were predictors of longitudinal
aphasia severity. Adding the volume of the right long segment to the first-level
model increased the overall predictive power of the model from 28% to 57%
[F(1,11) = 7.46, P = 0.02]. These findings suggest that different predictors of
recovery are at play in the left and right hemisphere. The right hemisphere
language network seems to be important in aphasia recovery after left hemispheric
stroke.
© The Author (2014). Published by Oxford University Press on behalf of the
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DOI: 10.1093/brain/awu113
PMID: 24951631 [Indexed for MEDLINE]