Apraxia of speech in degenerative neurologic disease

Background: Only a limited number of case reports or case series have provided unequivocal evidence that apraxia of speech (AOS) can be the first or predominant sign of neurodegenerative disease. This may reflect a very low frequency of occurrence but may also reflect a failure in many studies to identify AOS or distinguish it from the diagnosis of primary progressive aphasia (PPA). The distinction may be important to clinical neurological localisation and diagnosis, prognosis, management, and histopathology. Aims: To describe the demographic characteristics, presenting complaints, perceptual attributes, associated speech‐language and related clinical findings, neuroimaging findings, and clinical neurological diagnoses for a large group of patients with AOS due to degenerative neurologic disease. Methods an additional 18% received diagnoses related to focal/asymmetric cortical atrophy syndromes that localised to the left hemisphere; 29% received diagnoses of diseases with prominent motor manifestations, most often corticobasal degeneration, progressive supranuclear palsy, or motor neuron disease. Conclusions: AOS can be the first and most prominent manifestation of neurodegenerative disease. It often co‐occurs with aphasia and/or dysarthria, but it can be the only speech‐language disorder. It does not appear to be associated with any single neurologic disease but specific neurologic diagnoses, when they are possible, tend to reflect conditions with prominent motor manifestations. It is important to distinguish primary progressive AOS from PPA.