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 & Procedures: Retrospective review of patients seen between 1985 and 2004, who had AOS that was never less severe than any aphasia that might have been present and whose neurologic evaluation concluded that the cause was degenerative. Outcomes & Results: A total of 80 patients met inclusion criteria. Of these patients, 61% were men. Average age at initial evaluation was 69 years (range = 36–86 years). Speech‐language difficulty was the first symptom to emerge in 80% and the only patient complaint at the time of initial evaluation in 56%. Average duration of symptoms at initial evaluation was 29 months. Aphasia and dysarthria were unequivocally present in 49% and 50% of the sample, respectively. Of the 80 patients with AOS, 11% had neither aphasia nor dysarthria. When abnormal, neuroimaging often identified left or left>right hemisphere abnormalities. Of these patients, 44% received purely descriptive clinical neurologic diagnoses that were largely determined by speech‐language findings; 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.

Background: Primary progressive aphasia (PPA) and conditions that overlap with it can be accompanied by motor speech disorders. Recognition and understanding of motor speech disorders can contribute to a fuller clinical understanding of PPA and its management as well as its localisation and underlying pathology. Aims: To review the types of motor speech disorders that may occur with PPA, its primary variants, and its overlap syndromes (progressive supranuclear palsy syndrome, corticobasal syndrome, motor neuron disease), as well as with primary progressive apraxia of speech. Main Contribution: The review should assist clinicians’ and researchers’ understanding of the relationship between motor speech disorders and PPA and its major variants. It also highlights the importance of recognising neurodegenerative apraxia of speech as a condition that can occur with little or no evidence of aphasia. Conclusion: Motor speech disorders can occur with PPA. Their recognition can contribute to clinical diagnosis and management of PPA and to understanding and predicting the localisation and pathology associated with PPA variants and conditions that can overlap with them.

Apraxia of speech (AOS) can be caused by neurodegenerative disease and sometimes is its presenting sign (i.e., primary progressive apraxia of speech, PPAOS). During the last several decades, our un...

Primary progressive aphasia (PPA) and primary progressive apraxia of speech (PPAOS) are neurodegenerative syndromes characterized by progressive decline in language or speech. There is a growing number of studies investigating speech-language interventions for PPA/PPAOS. An updated systematic evaluation of the treatment evidence is warranted to inform best clinical practice and guide future treatment research. We systematically reviewed the evidence for behavioral treatment for speech and language in this population. Reviewed articles were published in peer-reviewed journals through 31 May 2021. We evaluated level of evidence, reporting quality, and risk of bias using a modified version of the American Speech-Language Hearing Association (ASHA) Levels of Evidence, an appraisal point system, additional reporting quality and internal/external validity items, and, as appropriate, the Single Case Experimental DesignScale or the Physiotherapy Evidence Database – PsycBITERating Scale for Randomized and Non-Randomized Controlled Trials. Results were synthesized using quantitative summaries and narrative review. A total of 103 studies reported treatment outcomes for 626 individuals with PPA; no studies used the diagnostic label PPAOS. Most studies evaluated interventions for word retrieval. The highest-quality evidence was provided by 45 experimental and quasi-experimental studies (16 controlled group studies, 29 single-subject designs). All (k = 45/45) reported improvement on a primary outcome measure; most reported generalization (k = 34/43), maintenance (k = 34/39), or social validity (k = 17/19) of treatment for at least one participant. The available evidence supports speech-language intervention for persons with PPA; however, treatment for PPAOS awaits systematic investigation. Implications and limitations of the evidence and the review are discussed.