The Value Of Auditory Comprehension Disorder In The Early Diagnosis Of Alzheimer’s Disease

objective: Alzheimber’s s disease(AD)is a progressive neurodegenerative disorder with cognitive,behavioral and functional disorders.It’s one of the most common diseases in the elderly and the most common type of dementia.Mild cognitive impairment(MCI)is a transitional state between normal aging and dementia,and its main manifestation is the impairment of memory or other cognitive functions,but not reaches the diagnostic criteria of dementia,and its daily living ability has not been significantly affected.Amnestic mild cognitive impairment(aMCI)is a subtype of MCI and high risk population of AD.The onset of Alzheimer’s disease whose short memory is mainly decline in the early stage is obscure.It is so easy to be confused with normal aging that patients are often in the middle or late stage when they go to see the docter.At present,the drug research of AD has been repeatedly frustrated,The drugs currently used are better effect for early AD patients,but only delay the symptoms.Therefore,the early diagnosis of AD is particularly important.The reasons why the current examinations which are used for the early diagnosis of AD are limited in clinical application are their invasive and relatively expensive price.So we need to find a simple,low risk and high diagnostic test to identify AD early.Auditory comprehension impairment is one of language comprehension impairments.Its pathogenesis may be related to the impairment of the brain regions and their connections related to auditory comprehension,which lead patients not to understand the meaning of the voice that they can hear.The early affected brain regions of AD are gray matter and white matter of temporal lobe and cingulate gyrus,and the early affected brain regions of MCI are frontal lobe,temporal lobe and posterior cingulate gray matter.Pathological and physiological changes of AD are the formation of senile plaques,neurofibrillary tangles and neurotransmitteracetylcholine reduction.The temporal lobe and frontal lobe are related to auditory comprehension,and the decline of acetylcholine is related to the changes in the regulatory function of the auditory cortex.In addition,it has been found that the central auditory pathway and auditory cortex of AD patients have also appeared the senile plaques,neurofibrillary tangles and neuron loss.Therefore,AD and MCI patients have a basis of auditory comprehension impairment.Whether auditory comprehension is a clinical indicator of AD’s early diagnosis that is a question which is worthy to be discussed.Therefore,our study analyzes the characteristics of mild Alzheimer’s disease(mild AD)and aMCI in auditory comprehension,and explores the value of auditory comprehension impairment in identifying mild AD and aMCI,so as to provide a new method for early diagnosis of AD.Methods : 1 、 According to the inclusion criteria and exclusion criteria,selected 49 aMCI patients(aMCI group)and 40 mild AD patients(mild AD group)in the Department of Neurology of Sichuan Provincial People’s Hospital from June 2016 to April2017,and selectde 40 normal controls from healthy family members 、caregivers and healthy volunteers in the Department of Neurology and medical examination center of our hospital during the same period.2、Use auditory comprehension test which is the auditory comprehension section of Aphasia Battery of Chinese to test subjects of three groups,and the auditory comprehension test include three subtests: Yes / no questions 、 Hearing and identifying、Oral instruction.3、Record the general data of each group and the results of each test.4、The datas were analyzed by SPSS17.0 software.Using Kruskal-Wallis rank sum test to compare the scores of cognitive function test and auditory comprehension test among three groups.Use Spearman or Pearson correlation analysis to analysis the correlation of auditory comprehension and cognitive function.The receiver operating characteristic curve(ROC)and the area under curve were used to evaluate the value of auditory comprehensiontest in identifying mild AD and aMCI.Results: 1、There were no significant differences in gender 、 age and education level among the three groups(all p>0.05).There were statistically significant differences in the cognitive functions(MMSE and MoCA)among the three groups(all p<0.05).2、There were significant differences in the scores of auditory comprehension total test and its sub tests among the three groups at p<0.05 level.Compared with the normal control group,all auditory comprehension test’s scores of aMCI group and mild AD group were reduced,the differences were statistically significant(p<0.017);Compared with aMCI group,only the Oral instruction’s score of mild AD group was reduced,the difference was statistically significant(p<0.017).3、In addition to auditory comprehension total test of aMCI group with MMSE(r=0.323,p=0.024)、 MoCA(r=0.340,p=0.017)and the Yes/no questions with MoCA(r=0.312,p=0.029)were positively correlated,most of auditory comprehension tests of aMCI group and mild AD group were not correlated with MMSE and MoCA(p>0.05).4、ROC curve analysis found that the area under curve(AUC)of auditory comprehension total test 、Yes / no questions 、 Hearing and identifying 、 Oral instruction distinguishing normal control group and aMCI group were 0.986、0.917、0.881、 0.903,suggesting that in addition to Hearing and identifying,the diagnostic accuracy of other auditory comprehension tests distinguishing the normal control group and aMCI group were all high,and auditory comprehension total test’s diagnostic accuracy was the highest(p<0.05);AUC of auditory comprehension total test 、Yes / no questions、Hearing and identifying、Oral instruction distinguishing normal control group and mild AD group were 0.987、 0.954、0.907、0.962,suggesting that the diagnostic accuracy of auditory comprehension tests distinguishing the normal control group and mild AD group were all high,and auditory comprehension total test’s diagnostic accuracy was the highest(all p<0.05);The AUC of Oral instruction distinguishing aMCI group and mild ADgroup was 0.657,suggesting that the diagnosis accuracy of Oral instruction distinguishing aMCI group and mild AD group was low(p<0.05).Conclusion:1 、 aMCI patients and mild AD patients have auditory comprehension impairment.2 、 The overall efficiency of auditory comprehension total test distinguishing a MCI and mild AD is high,which is beneficial to the early diagnosis of AD.3、Oral instruction in auditory comprehension tests is helpful to distinguish aMCI and mild AD.4、Auditory comprehension tests which are easy to be operated and take less time can partly eliminate the influence of educational level,and have a good clinical value.