Commentary: Metacognition and Perspective-Taking in Alzheimer’s Disease: A Mini-Review

Abstract

The neurocognitive approach points out how reduced self-awareness is related to cerebral disorders, particularly concerning focal lesions, emotional and motivational determinants, and concurrent neuropsychological impairments (Palermo, 2017a). Given its consequences on patients’ quality of life, caregivers’ burn-out, compliance with treatment, and prognosis, reduced self-awareness has received increasing attention on the part of neuroscientists (Fernández-Calvo et al., 2015). Indeed, a reduction in self-awareness has been found to be associated with a decline in help-seeking behaviour and compliance with medical treatment, presumably because of a reduction in motivation (Palermo, 2017a). In their brilliant mini-review, Bertrand and colleagues drew attention to the fact that neurological and neuropsychiatric patients can present severe - and often underestimated - impairments in metacognitive abilities that may result in “a lack of self-awareness of deficits”. Indeed, executive-metacognitive dysfunctions have been formerly associated with loss of self-awareness across major neurocognitive disorders likely due to Alzheimer’s Disease (AD) and frontotemporal dementia (Amanzio et al., 2011, 2013, 2016), Acquired Brain Injury (Palermo et al., 2014), Bipolar Disorder (Palermo et al., 2015) and Parkinson’s Disease (Amanzio et al., 2014; Palermo Palermo et al., 2017b Palermo et al., 2017c). Focusing on AD, Bertrand and colleagues (2016) dwelt on the association between metacognition and perspective-taking as a key aspect for improving quality of life in AD patients. These authors specified that “metacognition refers to the monitoring and regulation of cognitive processes and its impairment can lead to a lack of self-awareness of deficits, or anosognosia” (Bertrand et al., 2016 page 1). Anosognosia and reduced self-awareness are frequently used as synonyms in the literature and an overlap between them has been highlighted. This is a delicate question because according to the interpretation given to those terms, the methods of detection and interpretation of the phenomenon could change. This topic was recently treated by Mograbi and Morris (2018). In their interesting Discussion Forum, the authors not only emphasize how the term anosognosia continues to be the most used in the neurological field, but propose a glossary of labels that enhances the differences in use and interpretation of the epiphenomena to which they refer. In our opinion, the notion of “self-awareness” is not entirely concerned with the concept of “anosognosia”, since the former is a complex neuropsychological notion, defined as “the ability to consciously process information about ourselves in a manner that reflects a relatively objective view while maintaining our unique phenomenological or subjective sense of self” (Prigatano, 1997 page 301). Indeed, awareness of illness is above all a form of self-knowledge and a higher-order cognitive function covering information about the state of the disease, its functional consequences, the way in which it affects the patient and influences his/her interaction with the environment (Palermo, 2017a). In support of this theoretical framework, Stuss, Picton, and Alexander (2001) and Stuss and Anderson (2004) argued that there are several types of self-awareness (the so-called “consciousness” in their theoretical framework), organised hierarchically, which should be differentiated. As we have previously outlined, they proposed different elements in a four-level hierarchical framework of awareness, “where the processing in turn operates in a modular manner at any level of the hierarchy, so that damage in one functional domain may result in a different kind of reduced self-awareness” (Palermo et al., 2014, page 541). These four types of self-awareness have their own neural underpinnings in distinct substrates, with the lower levels related to a selective disturbance of knowledge [anosognosia] and the higher levels related to self-awareness, perspective-taking and Theory of Mind, with an emphasis on the role of the frontal and medial prefrontal brain areas (Palermo et al., 2017a). Indeed, the cognitive processes involved in metacognitive-executive functions and Theory of Mind have been associated with complex ecological contexts that require the recruitment of the anterior cingulate cortex and the ventromedial prefrontal cortex (Morese et al., 2016). Moreover, O’Keeffe et al. (2007) proposed that any disturbance in monitoring, cognitive flexibility and response inhibition has the potential to distort patients’ foresight (and thus self-awareness). Bertrand and colleagues (2016) suggested that the Default Mode Network may be useful to shed light on the role of perspective-taking in awareness of deficits in AD. They presented this relationship by referring to the Cognitive Awareness Model (CAM), which incorporates a comparator system within the central executive to detect mismatches between a personal database and exper