A – 112 Comorbid Multiple Sclerosis and Posterior Cortical Atrophy in a Young Woman

Abstract Objective Multiple sclerosis (MS) is associated with slowed processing speed and executive dysfunction with some variability on visuoconstruction measures. We present a case wherein the nature and extent of cognitive impairments exceeded typical findings for MS, suggesting a second, comorbid neurodegenerative process in a younger individual. Method A 43-year-old, right-handed, Latine woman with a GED diagnosed with MS (relapsing-remitting course) was evaluated for progressive cognitive concerns over seven years. Neurological exam revealed a right visual-field deficit. Brain MRI was consistent with MS but also showed disproportionate posterior regional atrophy that was atypical based on location of lesions and disease duration. She reported marked difficulty with visuospatially mediated tasks, not limited to those given her visual field deficit. Results Using a cut-off of < 1.5 SD, she demonstrated impairments in learning and memory, visuospatial reasoning, and visual attention, not attributable to her known visual field deficit. Performance on all measures of visually-mediated speed and attention was below the 2nd percentile and contrasted with preserved auditory attention. Learning was discrepant across measures with greater encoding of verbal information than non-verbal. Performance on tasks of auditory attention, working memory, and executive functioning were within expectations. Conclusion Given striking impairments on tasks requiring attention to or processing of visual information, we believe the patient demonstrated cognitive performance consistent with posterior cortical atrophy in addition to MS. This case study highlights the importance of consideration of low base rate, comorbid conditions with an appreciation for the cumulative burden of neurodegenerative processes that may alter age of onset and clinical course.