| Objective: With the acceleration of economic and social transformation and population aging in China,it is increasingly common that patients’ cognitive function declines faster than the speed of physiological aging,which seriously affects economic and social development and family happiness and harmony.China has become the country with the largest number of Alzheimer’s patients in the world.In order to implement the strategic deployment of the Party Central Committee and The State Council to comprehensively promote the construction of Healthy China,it is necessary to vigorously promote the development of screening methods for brain health and related brain diseases.However,the current common scale methods,biomarker methods and imaging methods cannot guarantee the widespread implementation of brain health screening because of the great influence of subjective factors,high invasiveness and high price.The decline of cognitive function is often accompanied by abnormalities of eye movement nerve,and the changes of eye movement characteristics can reflect the state of brain cognitive function such as memory function,executive function and visual search ability.Eye movement data can be used for early screening of cognitive function in a non-invasive manner,which is convenient for early intervention.More importantly,it can avoid the influence of patients’ subjective factors on the test results,and ensure the accuracy and objectivity of the test data.Based on the close relationship between eye movement and cognitive function,this paper designed a cognitive function evaluation method based on visual tracking technology.Five specific experiments were conducted to comprehensively evaluate brain functions such as executive function,visual working memory,short-term memory function,visual search ability,attention,visual search efficiency,selective attention and conflict management ability.From the perspective of high time,space dimension and eye movement,the level of each cognitive function of the subjects can be intuitively and significantly evaluated through specific values,and the decline of cognitive function can be quantified through the numerical differences,so as to achieve the purpose of early screening of patients with cognitive dysfunction.Methods: An eye movement assessment instrument for cognitive function was designed independently in this experiment.The eye movement information was measured by the eye movement instrument,and the cognitive function of the subjects was comprehensively evaluated according to the eye movement state and experimental performance.108 subjects were divided into three groups of different cognitive status according to the age standard.Five tests were designed in the experiment,which were number trail making test,number memory test,different word recognition test,saccade test and Stroop test.Digital wiring is mainly a computerized adaptation of TMT,which requires subjects to click targets on the device screen sequentially in order to test the subjects’ working memory ability.The digit memory test required the subjects to remember the digits on the screen for eight seconds,after which the digits disappeared,the subjects were asked to click out the corresponding digits of each target in order.The digit memory test was mainly used to measure the short-term memory function of the subjects.The alien word recognition experiment was used to measure the visual search ability of subjects by asking subjects to search 5 alien words in 9 rows and 16 columns of background words.The saccade experiment was divided into forward saccade and reverse saccade experiments.In the forward saccade experiment,the subject’s gaze was required to look at the position of the stimulus target presented.In the reverse saccade experiment,the subject’s gaze was required to look at the opposite position of the stimulus target presented.In addition,gaze information can also be used to analyze the subjects’ attention and visual capture ability.In the Stroop test,subjects were asked to click the corresponding Chinese character,color and color word according to the requirements,and the derived indexes were calculated according to the experimental performance to analyze the visual search efficiency,selective attention and conflict management ability of the subjects in complex situations.Results: 1.In the digital trail making test,the initial reaction time,initial path ratio,average reaction time and average path ratio of the elderly group were significantly higher than those of the middle-aged group and the young group,and the corresponding executive function and visual initial working memory levels were lower and declined greatly,and the number and duration of fixation for the region of interest were significantly increased.Visual search memory and executive function were better in the familiar context than in the distractor context.The numerical test has a significant effect on the assessment of executive function differences.2.In the digital memory test,there were significant differences in short-term memory function among subjects with different cognitive states,and the correct rate was divided into <70%,70%-90%and >90%;The average reaction time and average path ratio of subjects with poor shortterm memory function were higher than those of other groups,and the decrease of average reaction time and average path ratio were also different among different groups.The numerical memory test is effective in evaluating the difference of short-term memory function.3.In the different word recognition experiment,subjects with poor cognitive status had longer search time in each stage of visual search,and the corresponding first-round detection number was less.The proportion of disordered search mode in the youth group and the middle-aged group was similar,and the proportion in the elderly group was significantly increased.4.In the saccade test,the elderly group with poor cognitive status took more time in the saccade process than the young group and the middle-aged group,the latency of saccade was longer than the young group,the onset acceleration and termination acceleration were lower,and the corresponding executive function decreased significantly.The group with worse cognitive status also had significantly greater dispersion and deviation of fixation points before and after saccades.5.In the Stroop test,the average reaction time and accuracy of subjects with poor cognitive status were significantly decreased,and with the deterioration of cognitive status,the degree of decline was greater,and the ability to bear cognitive load was significantly decreased.In the derived indicators,the greater the effect of color interference on subjects with poor cognitive status,the lower the scores of brain state and behavioral state.Conclusion: The cognitive function assessment method based on visual tracking designed in this paper has been verified by subjects with significant cognitive differences at different ages.It has shown significant evaluation effects on executive function,visual working memory,short-term memory function,visual search ability,attention,visual search efficiency,selective attention and conflict management ability.It can not only quantitatively distinguish the differences between cognitive functions in different cognitive states,but also quantify the decline of cognitive function through the expression of specific values. |
PDF Full Text Request