阿尔茨海默症患者语言障碍研究现状和进展——基于病理语言学的实验研究综述

Studies on Alzheimer’s Patients’Language Impairments——An Overview of Experimental Studies Within the Framework of Pathological Linguistics

阿尔茨海默症是一种以进行性认知障碍和记忆能力损害为主的中枢神经系统退行性变性疾病。对阿尔茨海默症患者语言障碍的研究涉及语言学、神经心理学和脑认知科学。本文从两方面梳理了有关阿尔茨海默症患者语言障碍的实验研究:一是对音位、找词困难、句法、话语层面语言障碍的实验研究;二是基于眼动、脑电及脑成像等技术对患者语言障碍认知神经机制的实验研究。这些研究表明,目前相关实验研究主要集中在患者话语的词汇、句法及语义等方面,对患者语言使用的复杂性关注不够。亟待从交际语用角度对患者自然话语进行基于多模态语料库的系统研究。期待从事认知科学、言语治疗及相关领域研究的专家学者进一步研究阿尔茨海默症患者交际和认知关系的内在神经机制,以探索患者语言障碍康复治疗的有效途径。

Alzheimer’s disease(AD),which was first described by the German psychiatrist and neurologist Alois Alzheimer(1907),is a condition which results in a gradual and initially subtle deterioration of intellectual and eventually physical abilities,including memory and perceptual deficits,change in personality,loss of reasoning capacity,difficulty in maintaining attention,orientation,learning,and differential language loss.Elderly speakers suffering from Alzheimer’s dementia,the most common form of dementia,experience language impairments which need to be studied as a part of neurolinguistic study,ranging over linguistics,neuropsychology and cognitive science.Studies on Alzheimer’s patients’language impairments and discourse disabilities started in the 1980 s,and unbalanced contribution between researches carried out in the Europe and the Asian-Pacific region highlights the need of studying the discourse data of Alzheimer’s speakers in Asian-Pacific region,especially in China.As a new field of study,the study on discourse of Chinese AD patients from linguistic perspectives began a decade ago,with rather limited literature offering insight into potential disease effects on language and the relationship between language impairments and cognition.Based on previous studies carried out by psycholinguists,neurologists and speech pathologists,with speech samples elicited in clinical settings,this paper presents two main streams of research on the experimental study of Alzheimer’s discourse.One covers the analyses of phonology,wordfinding difficulty,syntax and discourse level,and the other involves researches on Alzheimer’s patients’cognitive neural mechanism of language impairments by means of eyetracking,EEG and brain imaging technology.As to communication abilities AD is characterized by losses in relation to word-finding abilities,ability to produce relatively complex sentences,and ability to self-correct,to control the topic and process language rapidly,and also by the confusion of cohesive devices,the use of"stereotypic language","empty speech",violations of conversational rules and limited use of certain speech acts.Recent literature on AD patients’communication focus on the analyses of lexis,syntax and semantics and do not give sufficient attention to the complexities of language use.AD patients’loss of conversational ability is likely to be an early marker of dementia syndrome.Conversations,as the most naturally occurring linguistic activities for AD patients,should be studied in particular to help researchers find out how patients behave in everyday life.The pragmatic abilities such as situated discourse abilities are seen to be extremely relevant to the nature of interaction of AD patients,in that pragmatic theory focuses on dynamic aspects of interaction,which are seen to be vulnerabilities of AD patients.This paper lays emphasis on the overview of discourse-related studies on AD patients including topic control ability,conversation structure,idea structure,speech act structure,information structure and interlocutor interaction framework.It is incumbent upon linguists to carry out systematic researches on Alzheimer’s patients’natural discourse from an interactional pragmatic perspective with multimodal corpus and together with professionals from speech pathology,cognitive science and other related fields further explore the neural mechanism underlying the interface between communication and cognition to lay the track of effective rehabilitation for Alzheimer’s patients.