Progressive apraxia of speech: A retrospective study

By J.R. Duffy

Primary progressive aphasia (PPA) is the most commonly cited example of cortical degenerative diseases that can have focal or asymmetric manifestations. In contrast, only infrequently has apraxia of speech (AOS) been reported as a prominent manifestation of degenerative neurologic disease. The few reported cases of progressive AOS have not consistently described its characteristics or adequately documented possible accompanying deficits such as nonverbal oral apraxia, dysarthria, or aphasia. This retrospective study documents and describes progressive AOS in 69 patients with degenerative neurologic disease. The average duration of the speech disorder at the time of initial evaluation was about 2.5 years. AOS was the predominant or only communication deficit in 47 patients (68%); 43 patients were aphasic and 35 were dysarthric. In 57 patients (83%), the speech disorder (AOS +/- aphasia or dysarthria) was the first symptom of neurologic disease. Demographic characteristics, co-occurrence of dysphagia, nonverbal oral apraxia and nonaphasic cognitive deficits, neuroimaging findings, and neurologic diagnoses are described. The results support a conclusion that AOS can be the only manifestation of a degenerative neurologic disease early in its evolution, or that it can be the predominant problem among a constellation of difficulties that frequently includes dysarthria, aphasia, and nonverbal oral apraxia.