The history of scientific and clinical analysis of brain from the perspective of language functions goes back to a very long time ago. Neurolinguistics is a branch of cognitive neuroscience, which forms a branch of a wider domain called nerves (
Dementia is one of the most common syndromes affecting the ages (
2). Suffering from dementia puts much burden on the patients, families and society because it declines the patients daily functioning and leads to loss of independence and more dependence on the others. In fact, “dementia is an acquired, degenerative and usually progressive disorder in cognitive functioning that affects the consciousness content and is a result of a disorder in cortesus, under cortesus relations or both” ( 3). Furthermore, dementia is a progressive deterioration that despite the normal state of consciousness, the consciousness itself has a failure ( 4). AD (Alzheimer’s disease) is probably the most significant degenerative neurological disease due to its high prevalence and its being devastating ( 3).
“This disease, similar to another types of dementia begins slowly and within 1 to 3 years leads to brain dysfunction, inability to control the motor impairment and in the end to devastation and death” (
Deficit in short-term memory is usually the first symptom of AD (
6). With the development of deficit in memory, the patient first loses his awareness of time and then his awareness of place ( 7). Paraphasia, logocolonia may also happen ( 8).
In addition, AD is a type of progressive dementia of which all the reasons that are reversible to health are totally rejected. Besides, AD is a slowly progressive disease that often appears after years of aphasia and Octozi and finally leads to problems in walking and pardysis (
From the epidemiological perspective, AD accounts for 50 to 60 percent of dementia cases. Also, AD is more common among women. 5 percent of the people above 65 years old between 10 to 20 percent of those above 80 suffer from AD (
3, 10, 11). However, the reason of AD is still unknown, but “the existence of viruses, genetic factors and intolerable levels of Aluminium and immunity system deficiency are influential” ( 5).
Moreover, Harrison considers the death of nerve cells in the cortex of brain as the main pathological feature of AD and this leads to atrophy in brain. In this phenomenon the cerebral ventriculitis is also evident in AD patients, but it isn’t much severe (
One of the tests for diagnosing and confirming AD is MMSE (mini mental state examination) (
12). This test was designed by Marchal Folestine in 1970 for screening brain dysfunction ( 13).
On the other hand, cohesion is one of the most significant concepts in discourse analysis. Discourse analysts believe that there are external elements between a text’s sentences and the context called cohesion devices. They create cohesion and semantic relation among the sentences and contribute to a better comprehension and interpretation of sentences as well as a proper perception of the speaker’s meaning (
As said by Dooley and Levinsohn, “cohesion can be defined briefly as the use of linguistic means to signal coherence”. Correspondingly, cohesive signals or ties “indicate how the part of the text with which they occur links up conceptually with some other part” (
15). In this regard, morpho-syntactic patterns are grouped as one of the cohesion devices that encompasses consistency of inflectional categories, echoic utterances and discourse-pragmatic structuring. According to Dooley and Levinson, a sequence of clauses and sentences can indicate the consistency of inflectional categories such as tense markers in verbs of sentences ( 15). Also, Alborzi emphasizes on the mandatory of this device in sentences which is more tangible in narrative texts since the tense refers to the sequence of events in these texts ( 16). In sentences 1 and 2 (see all examples in supplementary file Appendix 1), the verbs, for example, ʃekӕst ‘broke’, gozɑʃtand, ‘(they) put’, ʃod ‘became’, kӕrdӕnd ‘(they) did’ show a consistency with the verb form in the past tense. This phenomenon demonstrates that they are the events within the main narrative order. While the verbs Ɂɑmӕdim ‘(we) came’ and mir im ‘(we) go, as well as the verbs mikonim ‘(we) do’ and poxtim ‘(we) cooked’ in sentences 3 and 4 display a miscellaneous sequence of simple present tense and simple past tense, actually inconsistency in verb inflection.
In addition, as far as echoic utterances are concerned, there is a kind of, the whole or in part, morpho-syntactic repetition. “An echoic utterance is one which copies all or part of an earlier utterance, and it is obvious that the speaker intends it to do so. The echoic utterance calls attention back to the earlier utterance in order to imply a comment about it” (
15). In sentences 5 to 8, words like Ɂesme maen “my name, ba maʃin ‘by car’, Ɂesm-e ʃoma ‘your name’ and morde ‘dead’ refer to some examples of echoic utterances where some words are repeated; however, such repetitions are not fully carried out by the elderly with Alzheimer’s disease, as given in examples 7 and 9. Moreover, as to discourse-pragmatic structuring, only one pattern of this type, point of departure plus predication, has been investigated in this study. Points of departure are used “to link the following predication to something that the hearer is assumed to have already in his or her mental representation” ( 15). Similarly, the points of departure provide temporal or spatial situations for the expressions which follow them ( 15). In the examples 10 to 13, words like hӕfteje piʃ ‘last week’, salha bӕɁd ‘years later’ and Ɂӕlan ‘now’ show a discourse-pragmatic structuring in which the sentences are conjoined by temporal signals or markers. But the sentence 14 lacks such signals.
As for language disorders of patients with AD, some studies in English and a few in Persian have been carried out among which the following are reported.
Bates, Harris, Marchman, Wulfek and Kritchevsky have investigated making complex syntactic categories in AD patients and elderly control group’s speech. The results indicated grammatical problems in AD patients in a film description task. The problems did not occur clearly, the patients had problems in finding the best fit between grammatical forms and meaning (
Kempler, Curtissan and Jackso using conversational speech samples of AD subjects at the mild to severe stage, compared morpho-syntactical and lexical errors in patients and normed speakers. The results showed people with AD made more lexical than morphosyntactical errors. Also, they demonstrated that people with AD in comparison to normal speakers had similar functioning in using particular syntactical structures. Furthermore, the number of syntactic errors remained low despite the increases in dementia severity (
Furthermore, Ripich and Terrell analyzed cohesion devices in the speech of men and women suffering from AD in their longitudinal study. The results displayed people with AD had weak functioning, got worse with passage of time and the number of times using of cohesion devices decreased (
Ripich, Carpenter and Ziol analyzed a longitude study in conversational cohesion pattern in men and women with early to mid-stage AD and non-demented elderly. The results revealed significant ellipsis and conjunctions at 18 month post-entry. Likewise, as people with AD produced fewer and shorter utterance across time, their use of all cohesion devices decline (
Smith and Knight studied 25 patients with AD in De Flinders clinic in the University of Otego. The objective of this study was to analyze the automatic and controlled effects on memory processing in AD patients using process dissociation procedure. The patient group had fundamental deficits in controlling and remembering their memories as well as a decrease in their ability for automatic memory processing (
Khoddam also examined language properties of naming, comprehension, lexical extent and speech speed in elderly with Alzheimer. The result showed the patients had major problems in correctly naming and comprehending complex materials. They also spoke very slowly (
Malekzadeh et al. analyzed a 40 minute speech sample of six elderly people with AD and 6 elderly with ordinary speech in Persian language who had the same age, gender and education to carry out a comparative study. The results indicated the elderly with AD were different from the normal people in using grammatical and lexical cohesion devices. This group made more reference errors especially out of context than the normal group, also they used more repetition in using lexical cohesion devices (
St.-Pierre, Ska and Beland did a case study of cohesion deficiency in the speech of people with AD. The subjects were 29 people with AD and 29 normal people. The results displayed normal people produced more relevant utterances than irrelevant to the speech topic, while people with AD used relevant and irrelevant utterances equally (
Ahangar et al. investigated lexical relations device in speech of elderly Alzheimer patients and non-patients. They found that Alzheimer had a significant effect on the speech of the group with AD. In other words, there was a significant difference between the application of lexical relations device in the speech of the non-patients and elderly Alzheimer patients (
Since cohesion devices contribute to the semantic relationship between sentences and a better comprehension of the text, and considering the fact that one of the speech symptoms of the elderly with AD is giving reference to as a result of which the pronouns have no antecedent and the phrases are repetitive (
26), it is significant to recognize the differences they have in perceiving and applying cohesion devices to get a better understanding and interpretation of their speech. Further, a small number of studies on the language problems of elderly patients with AD has been done. Therefore, such issues suffice to provide the reason and the necessity of launching the present research.