title: Aphasia severity in chronic stroke patients: a combined disconnection in the dorsal and ventral language pathways.
abstract: BACKGROUND
  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).
  
  
  CONCLUSIONS
  The assessment of the integrity of this region may potentially have a clinical impact in neurorehabilitation and acute decision making.
authors.affiliation: CRICM-Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Paris, France INSERM, U1127; CNRS, UMR 7225, Paris, France COGIMAGE, Paris, France APHP, Service des Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France Univ Paris 11, IFR49, DSV/I2BM/NeuroSpin, Bat 145, Gif-sur-Yvette, France INSERM, AP-HP, Centre d'Investigation Clinique CIC9503, Département des Maladies du Système Nerveux, Hôpital Pitié-Salpêtrière, Paris, France charlotte.rosso@gmail.com.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Rosso
authors.affiliation: CRICM-Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Paris, France INSERM, U1127; CNRS, UMR 7225, Paris, France COGIMAGE, Paris, France.
authors.forename: Patricia
authors.initials: P
authors.lastname: Vargas
authors.affiliation: CRICM-Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Paris, France INSERM, U1127; CNRS, UMR 7225, Paris, France COGIMAGE, Paris, France Institut du Cerveau et de la Moelle épinière, Centre de Neuro-Imagerie de Recherche (CENIR), Paris, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Valabregue
authors.affiliation: APHP, Service des Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France Centre des maladies cognitives et comportementales, IM2A, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Arbizu
authors.affiliation: APHP, Service des Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France Centre des maladies cognitives et comportementales, IM2A, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: François
authors.initials: F
authors.lastname: Henry-Amar
authors.affiliation: APHP, Service des Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Leger
authors.affiliation: CRICM-Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Paris, France INSERM, U1127; CNRS, UMR 7225, Paris, France COGIMAGE, Paris, France APHP, Service des Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France Institut du Cerveau et de la Moelle épinière, Centre de Neuro-Imagerie de Recherche (CENIR), Paris, France APHP, Service de Neuroradiologie, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehéricy
authors.affiliation: CRICM-Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Paris, France INSERM, U1127; CNRS, UMR 7225, Paris, France COGIMAGE, Paris, France APHP, Service des Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Samson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001037:Aphasia / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D002908:Chronic Disease; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D020521:Stroke / Q000150:complications*; D066127:White Matter / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult
keywords: aphasia; diffusion tensor imaging; stroke