Abstracts

Rationale: Alexia without agraphia (AWA) is an acquired reading disorder in the absence of other new language problems. Historically it is associated with infarcts in the left occipital lobe and splenium of the corpus callosum. The combined lesions prevent incoming visual information from reaching language areas in the left hemisphere, leading to loss of reading skill.   Methods: Only rare cases of AWA have been reported in children, though the disorder is associated with a variety of neurologic disorders in adults.   We present a case of a child who experienced AWA after resection of epileptogenic regions in the left posterior region, a previously unreported complication and association.   Results: J.M was a 13 year-old right-handed female with intractable epilepsy due to hemorrhagic infarction in the left temporo-parieto-occipital region, associated with streptococcal group B infection. She underwent extraoperative subdural EEG monitoring, language mapping, and uncomplicated surgical resection of the inferior occipital, medial-occipito-parietal and posterior temporal regions. Presurgical baseline was significant for normal intellectual ability, adequate reading and spelling and a language disturbance.  Wada and fMRI demonstrated language lateralization on the left.  Visual field testing demonstrated a left visual field defect.  Six months  post-surgery language was unchanged and verbal intellectual function remained stable, however reading was disturbed though spelling remained at baseline.  Nine months post surgery JM continued to have difficulty with fluent reading; she read 3 syllable words fluently 70%,of the time and  5 syllable words fluently 50% of the time.   Post-surgical MRI demonstrated anticipated changes in the left occipital, posterior-temporal and mesial-parietal lobes. Changes in the left corpus callosum splenium and forceps major were also noted, consistent with the presumed anatomic distribution associated with dyslexia without dysgraphia.     Conclusions: AWA occured in the context of surgical resection of epileptogenic regions in the left posterior head region.  Informal assessment demonstrated that AWA, which had been evident immediately post-surgically persisted as long as 9 months post-surgery. This presented a challenge for JM as she returned to school.   1) JM’s visual field defect is not the cause of her reading difficulties; she had a left visual field defect prior to surgery.  On formal assessment reading difficulties were only observed post-surgery. 2) Damage to the splenium can occur after uncomplicated surgery, and in the context of a right visual field, defect leads to AWA. Children with reading established prior to surgical resection experience AWA  in a manner consistent with what is seen in adults. 3)   Children with resections in the left posterior head region who have a right visual field defect, even preceding surgery, should be evaluated for AWA . 5) AWA may persist, and  not  resolve prior to return to school.  5) Patients with left occipital lobe resections should be counseled presurgically regarding the risk of AWA.