Article

The contribution of lesion size and location in poststroke aphasia is
debated, especially the extent to which aphasia severity is affected by damage to
specific white matter areas. OBJECTIVE: To identify specific white matter areas
critical for poststroke aphasia global severity and to determine whether injury
to these areas had more impact on aphasia severity than the infarct volume.
METHODS: Twenty-three chronic poststroke aphasic patients were assessed with the
Aphasia Rapid Test (ART) and the Boston Diagnosis Aphasia Examination (BDAE)
global severity scales and underwent diffusion tensor and structural imaging.
Voxel-based diffusion tensor imaging regression analysis was used to determine in
which areas fractional anisotropy (FA) abnormalities were correlated with ART and
BDAE severity scales.
The relationships between aphasia severity, FA values, and
infarct volumes were investigated using global and partial correlations. RESULTS:
We found a critical area associated with aphasia severity overlapping with the
arcuate and the inferior fronto-occipital fasciculi, resulting in a combined
disconnection of the dorsal and ventral pathways. ART scores were inversely
correlated with FA values in this region, with greater severity present with
lower FA values (correlation coefficient = -0.833, P < .0001). The proportion of
variance explained by the FA value was higher than the proportion of variance
explained by the infarct volume (R (2) = 68% vs 27%, P = .01).
The impact of
infarct volume on aphasia severity disappeared when damage to this critical white
matter area was taken into account (P = .38). CONCLUSION: The assessment of the
integrity of this region may potentially have a clinical impact in neurorehabilitation and acute decision making.
CI - (c) The Author(s) 2014.

Langue : ANGLAIS