Contextual Information Processing In Scene Recognition In Patients With Mild Cognitive Impairment

BackgroundIn the real world,the objects we look at are always present in a specific environment and do not exist in isolation.The specific environment in which the objects exist is called the scene.Understanding object-scene relationships and to making use of contextual information are critical for object and scene recognition.ObjectiveTo investigate whether patients with mild cognitive impairment(Mild cognitive impairment,MCI)exhibited impairment in processing contextual information in scene and object recognition.MethodsThe subjects included in each trial of this study were divided into:the MCI group and the control group,as measured by the Montreal Cognitive Assessment(Montreal Cognitive Assessment,MoCA)scale.According to the optimal cut-off scores proposed by Huang et al,the MoCA cut-off scores for the three groups(low education,≤6 years;medium education,7-12 years;high education,>12 years)were≤19,≤22 and≤24 for MCI and≤13,≤15 and≤16 for mild dementia,respectively.In Experiment 1,subjects viewed images of foreground objects in semantically congruent or incongruent scenes,then they verbally reported the names of foreground objects and background scenes without time pressure.In Experiment 2,by performing a questionnaire,we examined the baseline accuracy of object and scene recognition,the difficulty of recognition,the familiarity with objects and scenes,and the judgment of object-scene consistency.In Experiment 3,subjects viewed individually presented foreground objects and verbally reported the names of the objects with a time limit.In Experiment 4,subjects viewed individually presented background scenes and verbally reported the names of the scene with a time limit.ResultsBoth MCI and control groups without time pressure showed a scene congruency effect in scene recognition,manifesting in more accurate scene recognition in the congruent condition than in the incongruent condition.However,MCI patients were more susceptible to inconsistent foreground objects in scene recognition compared to controls,which may be due to the inhibitory deficits of MCI patients.Furthermore,the questionnaire showed no group differences in consistency judgement,recognition accuracy,recognition difficulty and familiarity rating,indicating no significant impairment in object and scene knowledge in MCI group.Moreover,there was a possible category-specific recognition difficulty for both groups in recognizing scenes rather than objects.In the rapid recognition task,both groups were influenced by contextual information when recognizing objects,with higher recognition accuracy in the scene congruent condition than in the incongruent condition.However,no scene congruency effect was found in MCI patients compared to the control group in scene recognition,probably due to the reduced ability of MCI patients to process scene contextual information in the relatively short recognition time.Meanwhile,compared to the control group,MCI patients showed decreased accuracy in recognizing both objects and scenes.,indicating that the MCI group has an impairment in the ability to process objects and scenes under the conditions of limited recognition time.ConclusionThe study indicates that MCI patients exhibit a relatively intact contextual processing ability to recognize objects and scenes without time pressure,but their inhibitory ability is possibly impaired.However,in a fast object and scene recognition task,MCI patients have a impaired ability to process contextual information when recognizing scenes.Furthermore,there may be a category-specific difficulty in object and scene recognition:scene congruency effects in the recognition task without time pressure were observed only in scene recognition,and both groups in the questionnaire showed more difficulty in recognizing scenes than objects.However,this observation deserves further investigation.In addition,MCI affects fast object and scene recognition in the fast object and scene recognition task,as demonstrated by a significant decrease in object and scene recognition accuracy compared to the control group.In conclusion,the study improves our understanding of cognitive dysfunction in MCI patients,which may help identify better cognitive tests to detect MCI.