Longitudinal Multi-Modality Imaging in Progressive Apraxia of Speech

Inclusion Criteria: * We will study subjects that fulfill clinical inclusion criteria for neurodegenerative AOS that have been seen and diagnosed at Mayo Clinic Exclusion Criteria: * Subjects with concurrent illnesses that could account for speech and language deficits, such as traumatic brain injury, strokes or developmental syndromes will be excluded. * Women that are pregnant or post-partum and breast-feeding will be excluded. All women who can become pregnant must have a pregnancy test no more than 48 hours before the PET scan. * Subjects will also be excluded if MRI is contraindicated (metal in head, cardiac pace maker, e.t.c.), if there is severe claustrophobia, if there are conditions that may confound brain imaging studies (e.g. structural abnormalities, including subdural hematoma or intracranial neoplasm), or if they are medically unstable or are on medications that might affect brain structure or metabolism,(e.g. chemotherapy). * Subjects will also be excluded if they do not have an informant, or do not consent to research.