Apraxia and dementia severity in Alzheimer's disease: a systematic review.

Introduction: To investigate the role and influence of apraxia regarding dementia severity in Alzheimer's disease (AD). In addition, to examine whether apraxia or its association to dementia severity show distinct characteristics between typical and atypical variants of AD, that commonly include frontal, logopenic, posterior, and Down's syndrome variant.
Method: The search conducted on 4 December 2020 in the Cinahl, Ovid Medline, PsycArticles, PsycInfo, Scopus and Web of Science databases yielded 251 non-duplicate records published since 2000. Ten records examining the association between Clinical Dementia Rating (CDR) scores and apraxia in AD were included in the review.
Results: Dementia severity was related to apraxia in AD, and the prevalence and severity of apraxia increased as dementia progressed. Constructional, ideomotor (imitation of meaningless gestures), orofacial, speech, gait, and total praxis, including constructional, ideomotor, and ideational praxis, tasks differentiated dementia severity in AD. In the atypical variants of AD apraxia occurred frequently but because of the small number of participants, no statistical analyses were available.
Conclusions: The results highlight the need for extensive assessment of AD severity, and praxis assessment throughout the disease course. Apraxia affects the independent functioning and communication of the patient, tool use, and the ability to perform activities of daily living. Apraxia occurs frequently in AD and other neurodegenerative diseases, and apraxia assessment has shown to differentiate AD from other neurodegenerative diseases, particularly frontotemporal dementia. Thus, apraxia assessment serves in recognizing the atypical variants of AD as well.