Differential reorganization of fusiform gyrus in two types of alexia after stroke.
Lesions affecting the left fusiform gyrus (FG) commonly result in dyslexia and recovery largely depends on efficient reorganization of the reading network. We performed a follow-up fMRI study to elucidate the reorganization patterns of the FG according to the recovery of reading ability in two patients (MH with pure alexia and KM with alexia with agraphia) after stroke involving the left FG. Initially, MH was an effortful letter-by-letter (LBL) reader, and she improved to become a proficient LBL reader. The initial fMRI results showed scattered activation on occipital and ventral temporal cortex during reading, which was localized to right FG in the follow-up study. KM's severe alexia with agraphia did not improve, even after 6 months had passed since the onset of the alexia. The initial and follow-up fMRI results showed no significant activation in the bilateral FG or central higher language areas during word reading. Our results suggest that the reorganization of the FG is different according to the type of alexia and the amount of clinical recovery in each patient. Also, the successful reorganization of the visual component of reading in the right FG is responsible for the recovery of LBL reading in pure alexia.
Pyun
Sung-Bom
SB
Korea University Medical Center, Korea University College of Medicine, Physical Medicine and Rehabilitation, Seoul, Republic of Korea. rmpyun@korea.ac.kr
Sohn
Hyo-Jeong
HJ
Jung
Jae-Bum
JB
Nam
Kichun
K
D000222:Adaptation, Physiological; D000381:Agraphia / Q000209:etiology / Q000473:pathology*; D020237:Alexia, Pure / Q000209:etiology / Q000473:pathology*; D004411:Dyslexia, Acquired / Q000209:etiology / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008609:Mental Status Schedule; D008875:Middle Aged; D009473:Neuronal Plasticity; D020127:Recovery of Function; D020521:Stroke / Q000150:complications / Q000473:pathology; D013702:Temporal Lobe / Q000473:pathology*