MAPT and Aphasia: The other 6 cases with a clinical CBS phenotype exhibited 18F-AV-1451 retention in the motor cortex and subcortical white matter contralateral to the side of symptoms, where tau deposition is to be expected.22, –, 24 Further, the patient with CBS with a nonfluent aphasia (CBD-PNFA; case 6) had a predominantly left sided frontotemporal uptake of the tracer, corresponding to the clinical symptoms.