Background Abnormalities in eye movement metrics have been related to cognitive decline in dementia (Garbutt et al., 2008; Crawford et al., 2005), however, little is known about its association with executive dysfunction prior to the onset of Alzheimer’s disease (AD). The objective of this study was to determine whether older adults with mild cognitive impairment (MCI) or incipient dementia due to AD display subtle signs of impairment in executive functioning as compared to healthy controls, through the analysis of eye movement behavior. Method 93 elderly individuals were allocated into three groups according to cognitive status: normal controls (CTRL, n=28), mild cognitive impairment (n=44) and Alzheimer’s disease (n=21). All groups were tested with an eye tracking‐assisted protocol composed of a prosaccade (PS) and an anti‐saccade (AS) task. The PS task required a fast, automatic saccade towards a peripheral target stimulus. In the AS task (measure of executive functioning), subjects had to inhibit an prosaccade towards the target stimulus and initiate a voluntary saccade in the opposite direction. Result The PS task revealed a similar saccadic performance across the three groups. The AS task had a greater impact on the frequency and latency of eye movement metrics in each group, with AD subjects showing a greater executive decline than CTRL and with MCI group performing intermediately. MCI were similarly impaired as AD in their voluntary saccadic reaction times, with a longer time to correct erroneous saccades. Correlations revealed relationships between eye movement metrics in the AS and measures of inhibitory control, attention, working memory and self‐monitoring. Conclusion The three groups showed a similar pattern of eye movements in the PS task, with both patients groups revealing a preserved automatic saccadic control compatible with the pattern observed in healthy ageing. AS task confirmed that cognitive impairment in the MCI‐AD continuum affects eye movement patterns reflecting executive deficits in inhibitory control, working memory and executive‐attention control subjacent to voluntary saccades. MCI revealed an intermediary impairment in these executive domains, as compared to AD (highest impairment) and CTRL. However, they showed significant increased response times similar to AD subjects, in order to overcome these deficits.

The ABCD battery is a useful tool in the evaluation of adults and elderly with DS and the performance of individuals in this battery correlates with indices of functionality. This is a pioneer study in Brazil, and it points to the need for a better characterization of the linguistic abilities of individuals with DS, in order to allow the elaboration of strategies that stimulate their communicative abilities as to promote greater social insertion for this population.

Background: The assessment of language changes associated with visual search impairment can be an important diagnostic tool in the Alzheimer’s disease (AD) continuum. Objective: Investigate the performance of an eye-tracking assisted visual inference language task in differentiating subjects with mild cognitive impairment (MCI) or AD dementia from cognitively unimpaired older adults (controls). Methods: We assessed a group of 95 older adults (49 MCI, 18 mild dementia due to AD, and 28 controls). The subjects performed the same task under multiple experimental conditions which generate correlated responses that need to be taken into account. Thus, we performed a non-parametric repeated measures ANOVA model for verbal answers, and a linear mixed model (LMM) or its generalized version for the analysis of eye tracking variables. Results: Significant differences were found in verbal answers across all diagnostic groups independently of type of inference, i.e., logic or pragmatic. Also, eye-tracking parameters were able to discriminate AD from MCI and controls. AD patients did more visits to challenge stimulus (Control-AD, –0.622, SE = 0.190, p = 0.004; MCI-AD, –0.514, SE = 0.173, p = 0.011), more visits to the correct response stimulus (Control-AD, –1.363, SE = 0.383, p = 0.002; MCI-AD, –0.946, SE = 0.349, p = 0.022), more fixations on distractors (Control-AD, –4.580, SE = 1.172, p = 0.001; MCI-AD, –2.940, SE = 1.070, p = 0.020), and a longer time to first fixation on the correct response stimulus (Control-AD, –0.622, SE = 0.190, p = 0.004; MCI-AD, –0.514, SE = 0.173, p = 0.011). Conclusion: The analysis of oculomotor behavior along with language assessment protocols may increase the sensitivity for detection of subtle deficits in the MCI-AD continuum, representing an important diagnostic tool.

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Language complaints, especially in complex tasks, may occur in mild cognitive impairment (MCI). Various language measures have been studied as cognitive predictors of MCI conversion to Alzheimer's type dementia. Understanding textual inferences is considered a high-demanding task that recruits multiple cognitive functions and, therefore, could be sensitive to detect decline in the early stages of MCI. Thus, we aimed to compare the performance of subjects with MCI to healthy elderly in a textual inference comprehension task and to determine the best predictors of performance in this ability considering one verbal episodic memory and two semantic tasks. We studied 99 individuals divided into three groups: (1) 23 individuals with amnestic mild cognitive impairment (aMCI), (2) 42 individuals with non-amnestic mild cognitive impairment (naMCI), (3), and (4) 34 cognitively healthy individuals for the control group (CG). A reduced version of The Implicit Management Test was used to assess different types of inferential reasoning in text reading. MCI patients performed poorer than healthy elderly, and there were no differences between MCI subgroups (amnestic and non-amnestic). The best predictors for inference-making were verbal memory in the aMCI and semantic tasks in the naMCI group. The results confirmed that the failure to understand textual inferences can be present in MCI and showed that different cognitive skills like semantic knowledge and verbal episodic memory are necessary for inference-making.