Comparing the Effect of Interference on an Emotional Stroop Task in Older Adults with and without Alzheimer’s Disease

The assessment of executive function abilities in healthy and neurodegenerative aging-A selective literature review

Numerous studies have examined executive function (EF) abilities in cognitively healthy older adults and those living with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Currently, there are no standard accepted protocols for testing specific EFs; thus, researchers have used their preferred tool, which leads to variability in assessments of decline in a particular ability across studies. Therefore, there is a need for guidance as to the most sensitive tests for assessing EF decline. A search of the most current literature published between 2000 and 2022 on EF studies assessing cognitively healthy older adults and individuals living with MCI and AD was conducted using PubMed/Medline, PsycINFO, Embase, Web of Science, and Google Scholar. Emphasis was placed on the EF's dual-tasking, inhibition, shifting or switching, and working memory updating. Many tasks and their outcomes were reviewed. Of particular importance was the difference in outcomes for tasks applied to the same group of participants. These various EF assessment tools demonstrate differences in effectively identifying decline in EF ability due to the aging process and neurodegenerative conditions, such as MCI and AD. This review identifies various factors to consider in using particular EF tasks in particular populations, including task demand and stimuli factors, and also when comparing differing results across studies.

Differential effects of faces and words in cognitive control in older adults with and without major depressive disorder: An emotional Stroop task study

Aging and major depressive disorders have been associated with impaired cognitive control. These deficits are also influenced by the affective valence and by the type of stimulus processed. Using an emotional Stroop task, the current study aims to examine cognitive control deficits and their association with emotion regulation in depression and the influence of the type of stimulus (words and faces) in this association. A total of 26 older patients with a major depressive disorder (MDD) (19 women; age range: 65-84 years) and 26 older healthy controls (18 women; age range: 65-80 years) participated in the study. The results showed that MDD individuals presented greater Stroop effects than their healthy controls and an absence of the conflict adaptation effect defined as a reduction of the influence of irrelevant stimulus dimensions after incongruent trials. Additionally, our results also showed that the processing of emotional words in depressed participants is more automatic than the processing of emotional faces. These findings suggest that older depressed individuals have greater difficulty in recognizing affective facial expressions than older healthy controls, while the over-learned behavior of word reading greatly reduces differences in the performance of the emotional Stroop task between groups (MDD and healthy controls).

Comparison of Emotion Recognition in Young People, Healthy Older Adults, and Patients with Mild Cognitive Impairment

BACKGROUND

The basic discrete emotions, namely, happiness, disgust, anger, fear, surprise, and sadness, are present across different cultures and societies. Facial emotion recognition is crucial in social interactions, but normal and pathological aging seem to affect this ability. The present research aims to identify the differences in the capacity for recognition of the six basic discrete emotions between young and older healthy controls (HOC) and mildly cognitively impaired patients (MCI).

METHOD

The sample (N = 107) consisted of 47 young adults, 27 healthy older adults, and 33 MCI patients. Several neuropsychological scales were administered to assess the cognitive state of the participants, followed by the emotional labeling task on the Ekman 60 Faces test.

RESULTS

The MANOVA analysis was significant and revealed the presence of differences in the emotion recognition abilities of the groups. Compared to HOC, the MCI group obtained a significantly lower number of hits on fear, anger, disgust, sadness, and surprise. The happiness emotion recognition rate did not differ significantly among the three groups. Surprisingly, young people and HOC did not show significant differences.

CONCLUSIONS

Our results demonstrated that MCI was associated with facial emotion recognition impairment, whereas normal aging did not seem to affect this ability.

Effect of stimuli type on affective memory of patients with different severities of cognitive impairment

OBJECTIVES

To understand the differences in affective memory performance under different degrees of cognitive impairment, this study recruited older people with different degrees of cognitive impairment, to perform emotion recognition memory tasks.

METHODS

Fifty-four elderly participants aged (65-85 years) were recruited. Of these, 18 had mild cognitive impairment, 18 had a mild form of Alzheimer's disease, and the remaining 18 were healthy. Factors such as the different emotional valences (positive, neutral, or negative) and stimulus types (pictures, words, or sounds) were manipulated to explore their influences on the emotion recognition memory of people with different degrees of cognitive impairment.

RESULTS

The results showed that people's performance to positive stimuli worsened as their degree of cognitive impairment increased. All participants had difficulty processing memory of affective sound stimuli compared to the other two stimulus types.

CONCLUSIONS

The results explain the decline in the cognitive ability process, in affective memory performance, of people with different degrees of cognitive impairment. This abnormal decline on affective memory performance could be an early diagnostic indicator of Alzheimer's disease. The results can hopefully be used as a reference for subsequent research on cognition-related diseases and age-related decline, especially regarding affective memory.

Emotion Processing Dysfunction in Alzheimer's Disease: An Overview of Behavioral Findings, Systems Neural Correlates, and Underlying Neural Biology

We described behavioral studies to highlight emotional processing deficits in Alzheimer's disease (AD). The findings suggest prominent deficit in recognizing negative emotions, pronounced effect of positive emotion on enhancing memory, and a critical role of cognitive deficits in manifesting emotional processing dysfunction in AD. We reviewed imaging studies to highlight morphometric and functional markers of hippocampal circuit dysfunction in emotional processing deficits. Despite amygdala reactivity to emotional stimuli, hippocampal dysfunction conduces to deficits in emotional memory. Finally, the reviewed studies implicating major neurotransmitter systems in anxiety and depression in AD supported altered cholinergic and noradrenergic signaling in AD emotional disorders. Overall, the studies showed altered emotions early in the course of illness and suggest the need of multimodal imaging for further investigations. Particularly, longitudinal studies with multiple behavioral paradigms translatable between preclinical and clinical models would provide data to elucidate the time course and underlying neurobiology of emotion processing dysfunction in AD.

It is not always positive: emotional bias in young and older adults

Healthy ageing has been associated with a bias toward positive information and greater psychological well-being. However, to what extent this positivity bias also applies to prioritizing positive information under emotional competition is unclear. Old and young adults performed a word-face interference task, in which they responded to the valence of positive and negative target-words while ignoring happy or angry distractor-faces that could be affectively congruent or incongruent. A control condition with scrambled neutral distractor-faces was also used. Findings showed small facilitation effects with faster responses when targets and distractors were affectively congruent and large interference effects with slower responses when targets and distractors were affectively incongruent compared to the control condition. Importantly, whereas for younger adults there was a similar pattern of interference from happy and angry distractor-faces, for older adults there was greater interference from angry distractor-faces. The present findings are discussed in the context of emotional bias literature.

Dimensional and Discrete Emotional Reactivity in Alzheimer's Disease: Film Clips as a Research Tool in Dementia

BACKGROUND

No studies have been conducted to date on the dimensional and discrete classification of emotions to study the emotional reactivity of older adults with Alzheimer's disease (AD). Additionally, the presentation of film clips with affective content is currently one of the most effective and widely used Mood Induction Procedures (MIPS). However, it has been scarcely used in AD patients.

OBJECTIVE

Based on the dimensional and discrete models of emotion, this study examines the emotional reactivity of older adults with AD, using a popular set of film clips to induce emotions.

METHODS

We compared the responses of older adults aged over 65-years with mild to moderate AD (n = 15) and a healthy comparison group (n = 17) to six target emotions: disgust, fear, anger, sadness, amusement, and tenderness.

RESULTS

The results showed significant differences in the reactivity of fear, anger, and sadness between AD patients and healthy comparison group. However, the responses of the two groups to positive film clips were similar. Only in the amusement clip did the AD participants show a higher intensity response.

CONCLUSION

These findings suggest that the characteristic loss of cognitive abilities in AD is related to a reduction in the ability to react to emotional stimuli, especially negative ones. However, these abilities seem to be preserved when it comes to positive emotions. Future research is necessary to investigate whether the positivity effect is present in AD patients.