PMC4776332_01
T1-weighted image sections from a 14.05 year old male with evidence of BPS. Left: Note the atypical formation of the Sylvian fissure (arrows) that merges with the intraparietal sulcus and surrounding polymicrogyria. Right: Standardized scores for cognitive assessments that were available for the BPS case. Performance in the normal range was observed for Wechsler Matrix Reasoning, Peabody Picture Vocabulary Test Receptive Vocabulary knowledge, and Rapid Automatic Naming for letters, numbers, and colors. Below average performance was observed for Woodcock-Johnson measures of pseudo-word and real word decoding, reading comprehension, spelling, writing fluency, and Comprehensive Test of Phonological Processing memory for digits. Particularly low Gray Oral Reading Tests and Test of Word Reading Efficiency fluency summary scores indicated a significant deficit in rapid access to lexical information compared to sub-lexical information given his relatively normal RAN Letter scores. Comprehensive Test of Phonological Processing (CTOPP); Gray Oral Reading Tests (GORT); Peabody Picture Vocabulary Test (PPVT3); Rapid Automatized Naming (RAN); Test of Word Reading Efficiency (TOWRE); Woodcock-Johnson (WJ)
nihms761604f1.jpg
PMC4776332_01_nihms761604f1.jpg
F1
BPS (Figure 1). BPS cases exhibit bilateral dysgenesis of the Sylvian fissure and surrounding gyri, which appears to occur because of a limited or absent arcuate fasciculus. He demonstrated relatively average general cognitive function compared to below average phonological processing skills (Figure 1).
Left: The BPS case had a white matter image similarity estimate (scaled score that was adjusted for potential effects of scanner differences across the 7 sites) that was more than 2 standard deviations below the mean of 10 male control cases and 19 male reading disability cases who were selected to be aged matched to the BPS case. Gray matter image similarity did not characterize the BPS case as an outlier despite the atypical Sylvian fissure patterning and cortical dysplasia that is consistent with polymicrogyria. Right: The BPS case was not an outlier when examining total white matter volume that was estimated from the summed voxel probabilities from native space white matter images that were segmented with default segmentation parameters using SPM8.
nihms761604f2.jpg
PMC4776332_01_nihms761604f2.jpg
F2
The BPS case had a white matter similarity estimate that was more than 2 standard deviations below the mean of the control and reading disability groups, but exhibited a total white matter volume estimate that was within the normal range of control and reading disability cases (Figure 2). Relatively mild BPS symptoms are consistent with the absence of epilepsy and perhaps relatively normal total white matter volume (Figure 2) despite likely dysgenesis of the arcuate fasciculus.