Incompleteness features in the descriptive discourse of Chinese elders with and without Alzheimer 's disease.

Alzheimer's disease (AD) can manifest itself with prominent language dysfunction. Incompleteness in discourse refers to the lack of indispensable sentence-constructing elements that hinder communication fluency and accuracy. The current study investigates how the pattern of incompleteness is associated with the descriptive discourse produced by elders without AD and those with different stages of AD. The Chinese discourse samples were collected from the picture description of 40 elders with mild probable AD (Mini-Mental State Examination (MMSE) 21-26, Montreal Cognitive Assessment Scale-Basic (MoCA-B) 15-19), 40 elders with moderate probable AD (MMSE 11-20, MoCA-B 10-14), and 40 controls (MMSE 26-29, MoCA-B 24-29). The total production of incomplete sentences and six incompleteness features were examined. The Mild AD, Moderate AD, and Control groups differed in the total output of the incomplete sentence. Group differences also emerged in four incompleteness features: missing subject, missing predicate, missing object, and missing functional word. The Moderate AD group differed from the Mild AD group with respect to most significant features, while Mild AD and Control groups were very similar. The results suggested that AD impairs the sentence construction ability of Chinese elders, especially at the later stage. These statistically significant differences between the groups might provide some references when diagnosing the risk and possibility of cognitive impairment of Chinese elders, facilitating the design of clinical evaluation or screening for probable AD.