Cognitive Effects of Late Life Depression: Review of Neuropsychological Findings

Abstract

Normal aging and depression both slow information processing speed which leads to poorer attentional control, shallower inhibition monitoring, poorer encoding, poorer updating of short term memory, and subsequent poorer learning, set-shifting, error monitoring, inhibition control, and cognitive planning. A combination of aging and depression amplifies these cognitive effects. Deterioration in frontal brain functioning in normal aging is irreversible, but altering of frontal brain function due to depression may be reversible. Since the symptoms are indistinguishable, it is difficult to separate effects of depression and aging with use of neuropsychological tests, even when premorbid history is known. Statistical group effects show more severe cognitive effects in late life depression than in normal aging or depression in younger persons, but no particular cognitive markers of depression in older subjects have been identified. Attention and inhibition are closely related, but their relationship needs to be studied further. It is not clear, whether a problem with inhibition of irrelevant stimuli occurs because of attentional deficits due to late life depression, or if it is a primary consequence of the depression. Further studies on the relationship between inhibition, attention and processing speed involving homogeneous depressed and nondepressed groups of different age may help disentangle this relationship.

Cognitive reserve-mediated neural modulation of emotional control and regulation in people with late-life depression

“…An initial direct comparison of the emotional words vs neutral words condition (collapsed across group) yielded significant activations in several frontal and parietal regions, including bilateral MFG, right AI, left posterior insula, right ACC, right IFG, left DLPFC, bilateral fusiform gyrus, bilateral lingual gyrus, right supramarginal gyrus, left angular gyrus, left postcentral gyrus and left middle temporal gyrus. All of these regions have previously been reported in several studies using similar interference paradigms (Ochsner & Gross, 2005; Blasi et al ., 2007; Korsnes & Ulstein, 2014). The direct comparison of emotional vs neural words contrast between the two groups clearly demonstrates that healthy controls (HEC) showed greater activation in bilateral MFG, left DLPFC and left angular gyrus relative to LLD.…”

“…Moreover, a recent meta-analysis study indicated that elderly patients with AD and higher CR exhibited greater activation in the anterior cingulate cortex (ACC) during cognitive tasks relative to those with lower CR (Colangeli et al ., 2016). These findings suggest that elderly individuals with higher levels of CR are more capable of recruiting alternative and/or additional brain networks to respond to cognitive changes due to pathological aging, especially within the prefrontal regions (Korsnes & Ulstein, 2014; Scarmeas & Stern, 2004; Stern et al, 2018b).…”

“…The concept of neural compensation is often invoked in fMRI studies in regard to neural mechanisms involved in the response to age- and disease-related brain pathology (Barulli & Stern, 2013; Stern et al ., 2018b). Neural compensation refers to an inter-individual variability in the capacity to compensate for brain pathology by making more efficient use of neural networks and recruiting alternative brain circuits (Park & Reuter-Lorenz, 2009; Grady, 2012; Huang et al ., 2012; Stern, 2012; Korsnes & Ulstein, 2014; Cabeza et al ., 2018). Evidence from recent functional neuroimaging studies reveals that higher CR was associated with greater activation in task-related brain regions in elderly patients with AD (Scarmeas et al ., 2004; Sheline et al ., 2006).…”

A Short Review of Factors and Interventions for Reducing Depression

“…Improving cognitive functioning (information processing speed, attention control, short term memory, learning and cognitive planning, sensory discrimination) is important for diminishing the negative effects from depression [21,22]. Self-expression by means of overt and assertive behaviour, as well as self-realization give the possibilities for students' improved cognitive functioning in the academic environment [23], and aesthetic experiences in the learning process also contribute to positive emotions and further development of cognitive functioning by means of complex processing of information [24].…”

The Effect of Cognitive Speed of Processing Training on the Development of Additional IADL Difficulties and the Reduction of Depressive Symptoms

“…Support for the expectation that cognitive SOPT would have a beneficial downstream effect by reducing depressive symptoms is more exploratory and stems from two sets of empirical evidence. The first is the well-established association between processing speed and depression (Dybedal, Ranum, Sundet, Gaarden, & Bjolseth, 2013; Korsnes & Ulstein, 2014; McClintock, Husain, Greer, & Cullum, 2010; Thomas & O’Brien, 2008; van den Kommer et al, 2013). Because the etiology underlying that association remains contested, all of the authors cited above have concluded that additional study is needed.…”