Study of the levels of processing in language production in bilingual patients with Alzheimer's disease from early to medium stage

The ability to preserve a good command of two languages decreases with old age. This decline can be more observed in bilingual patients with Alzheimer's disease (AD). The linguistic deficit is the most frequent cognitive disturbance after memory disorders in AD semiology. Besides, most of the studies dealing with the linguistic semiology of the AD were essentially interested in describing the linguistic behavior of the monolingual people, and based on modest samples. This study aims to locate the disturbed levels of processing in language production of bilingual Alzheimer's subjects by analyzing the discourses of 120 participants including 60 bilingual patients with Alzheimer's disease and 60 healthy bilinguals. The results focus on the deficit of processing in language production of bilingual patients with Alzheimer's disease at the semantic level of the first language in two aspects, which are the procedure based on the lexical implications of the terms and the continuity. However, the grammatical aspects in the second language (connector and deictic) are dysfunctional, while they are relatively preserved in the first language (L1). It appears that the semantic aspects are affected and the grammatical aspects are relatively spared on the first language, however the grammatical aspect of the second language is affected. The grammatical aspect of L1 resists better because it depends on procedural memory that is relatively resistant to AD; however, the semantic aspect of the L1 and grammatical aspect of L1 are disturbed in the L2 too because they depend on the declarative memory which is early disturbed.