A - 84 Neuropsychological Phenotypes of FDG-PET Identified Corticobasal Degeneration Pathology

OBJECTIVE: Corticobasal degeneration (CBD), a rare neurodegenerative disorder, can present with diverse clinical phenotypes. This qualitative case series examines clinical progression of neuropsychological findings associated with CBD identified pathology on fluorodeoxyglucose-positron emission tomography (FDG-PET). METHOD: Three clinically referred older adults underwent neuropsychological assessment prior to and after FDG-PET. All patients reported subjective memory complaints. Patient A: 67-year-old female with swallowing difficulty. Patient B: 83-year-old male with decreased balance. Patient C: 77-year-old male with gait disturbance. Neuropsychological re-evaluations occurred at 64, 19, and 17 months, respectively. Radiological interpretations of FDG-PET hypometabolism were reviewed. Clinically significant changes were defined as >1 standard deviation discrepancy from baseline performance. RESULTS: Patients A & C had predominant right hemisphere hypometabolism, and Patient B had predominantly left hemisphere hypometabolism. Patient A: hypometabolism for R > L frontoparietal, right temporal and occipital regions. Neuropsychological declines in left fine motor control/speed, attention, visual memory, and semantic fluency. Patient B: hypometabolism for left temporal, frontal, parietal, and occipital regions. Neuropsychological declines in semantic fluency and set-shifting. Patient C: hypometabolism for diffuse right hemisphere, including thalamus and basal ganglia. Neuropsychological declines in verbal learning and memory. There were no significant neuropsychological improvements for Patients A or C. Significant neuropsychological improvement for Patient B was evident for verbal memory and naming. CONCLUSIONS: The present case series highlights the diverse clinical presentation associated with CBD identified pathology on FDG-PET. Further studies are needed to characterize clinical phenotypes of CBD as they relate to quantitative FDG-PET pathology.