Early Emotional Attention is Impacted in Alzheimer’s Disease: An Eye-Tracking Study

Abstract

Emotional deficits have been repetitively reported in Alzheimer's disease (AD) without clearly identifying how emotional processing is impaired in this pathology. This paper describes an investigation of early emotional processing, as measured by the effects of emotional visual stimuli on a saccadic task involving both pro (PS) and anti (AS) saccades. Sixteen patients with AD and 25 age-matched healthy controls were eye-tracked while they had to quickly move their gaze toward a positive, negative, or neutral image presented on a computer screen (in the PS condition) or away from the image (in the AS condition). The age-matched controls made more AS mistakes for negative stimuli than for other stimuli, and triggered PSs toward negative stimuli more quickly than toward other stimuli. In contrast, patients with AD showed no difference with regard to the emotional category in any of the tasks. The present study is the first to highlight a lack of early emotional attention in patients with AD. These results should be taken into account in the care provided to patients with AD, since this early impairment might seriously degrade their overall emotional functioning.

Impact of emotionally negative information on attentional processes in normal aging and Alzheimer’s disease

“…This finding strongly supports the relevance of performing a separate assessment of engagement and disengagement processes to investigate emotional attention in aging and neurodegenerative disorders. In addition, our findings are in agreement with (a) reports in which patients had difficulty in quickly focusing their attention on emotional information (Bourgin et al, 2018;Hot et al, 2013), and with (b) the presence of an early amygdala atrophy in AD, this area being particularly involved in early emotional attention (Pourtois et al, 2013;Schwabe et al, 2011;Vuilleumier, 2005).…”

“…Consistent with the literature (Bourgin et al, 2018;Hahn et al, 2006;Leclerc and Kensinger, 2008a;Mather and Knight, 2006;Rösler et al, 2005b), HOAs engaged their attention more quickly (reflected by earlier fixation) and efficiently (reflected by flatter slope) on negative than on neutral content. This suggests that, in HOAs and in YAs, emotionally negative information is more likely to be perceived by covert attention, which preferentially guides overt attention to it.…”

“…To this end, we used an eye-tracking paradigm and a visual search task that involved emotional and neutral targets. On the basis of studies in AD that suggested (a) impairment of early engagement toward emotional stimuli in AD (Bourgin et al, 2018), (b) preservation of the impact of emotional information on delayed attentional processes in AD (Berger et al, 2015;Doninger and Bylsma, 2007;LaBar et al, 2000;Monti et al, 2010), and (c) early alterations of the amygdala, which seems preferentially involved in engagement processes, we expected to observe selective impairment of engagement mechanisms toward emotional information in patients with AD (relative to HOAs and YAs). Regarding normal aging, some studies suggest that HOAs are more efficient than YAs at inhibiting negative information (Hahn et al, 2006;Mather and Carstensen, 2003).…”

“…Studies that specifically address attentional processing are, however, still scarce and have provided inconsistent findings. Previous works suggest that patients with AD may be impaired in orienting their attention toward emotional information (Asaumi et al, 2014;Bourgin et al, 2018;García-Rodríguez et al, 2012;Hot et al, 2013). Other studies showed that patients with AD present difficulties in inhibiting or disengaging from emotional distractors (Berger et al, 2015;Doninger and Bylsma, 2007;Monti et al, 2010).…”

“…Note that most of the previous studies (a) did not use purely attentional protocols (e.g., working memory tasks that involved emotional distractors) and/or (b) did not allow a clear dissociation between the different attentional processes that were potentially involved, namely, engagement and disengagement mechanisms. To our knowledge, the only study that involved a protocol that directly measured attentional processes used a pro-saccade/anti-saccade paradigm and showed impairment in early engagement processes in patients with AD (Bourgin et al, 2018). Taken as a whole, these data indirectly suggest that patients with AD may present impaired engagement processes toward emotional information, but are unaffected by (or even show an increase in) the influence of emotion on disengagement processes, consistently with a critical involvement of the amygdala in facilitating attentional orienting toward emotional stimuli.…”