Speech and orofacial apraxias in Alzheimer's disease

Alzheimer's disease (AD) affects not only memory but also other cognitive functions, such as orientation, language, praxis, attention, visual perception, or executive function. Most studies on oral communication in AD focus on aphasia; however, speech and orofacial apraxias are also present in these patients. The aim of this study was to investigate the presence of speech and orofacial apraxias in patients with AD with the hypothesis that apraxia severity is strongly correlated with disease severity. Ninety participants in different stages of AD (mild, moderate, and severe) underwent the following assessments: Clinical Dementia Rating, Mini-Mental State Examination, Lawton Instrumental Activities of Daily Living, a specific speech and orofacial praxis assessment, and the oral agility subtest of the Boston diagnostic aphasia examination. The mean age was 80.2 ± 7.2 years and 73% were women. Patients with AD had significantly lower scores than normal controls for speech praxis (mean difference=-2.9, 95% confidence interval (CI)=-3.3 to -2.4) and orofacial praxis (mean difference=-4.9, 95% CI=-5.4 to -4.3). Dementia severity was significantly associated with orofacial apraxia severity (moderate AD: β =-19.63, p= 0.011; and severe AD: β =-51.68, p < 0.001) and speech apraxia severity (moderate AD: β = 7.07, p = 0.001; and severe AD: β =8.16, p < 0.001). Speech and orofacial apraxias were evident in patients with AD and became more pronounced with disease progression.