Disentangling the relationship between cognitive estimation abilities and executive functions: a study on patients with Parkinson’s disease

Abstract

The cognitive estimation test (CET) measures cognitive estimation abilities: it assesses the ability to apply reasoning strategies to answer questions that usually cannot lead to a clear and exact reply. Since it requires the activation of an intricate ensemble of cognitive functions, there is an ongoing debate in the literature regarding whether the CET represents a measurement of global cognitive abilities or a pure measure of executive functions. In the present study, CET together with a neuropsychological assessment focused on executive functions was administered in thirty patients with Parkinson's disease without signs of dementia. The CET correlated with measures of verbal working memory and semantic knowledge, but not with other dimensions of executive domains, such as verbal phonemic fluency, ability to manage real-world interferences, or visuospatial reasoning. According to our results, cognitive estimation abilities appeared to trigger a defined cognitive path that includes executive functions, namely, working memory and semantic knowledge.

Cognitive Estimation in Non-demented Parkinson's Disease

“…Despite some PD individuals being impaired on the CET according to the cut-offs for the standardized versions, significant differences between the PD and healthy control groups were not found on either version of the CET (Scarpina et al, 2015). This supports previous results about which only small numbers of non-demented PD patients perform below the cut-off on other CET versions (Appollonio et al, 2003;D'Aniello et al, 2015a). In addition, our results showed that the PD and healthy control groups did not significantly differ in their initial and final responses provided or the number of response changes, which suggests that PD patients do not improve their CET performance if given the opportunity to revise their initial responses.…”

“…However, in non-demented PD individuals, Appollonio and colleagues (2003) did not find deficits in CET, with only 6% of the studied participants performing below the impaired cut-off. More recently, our own work has reported cognitive estimation deficits in non-demented medicated PD patients, but again in only a small number of individuals (approximately 16% of the studied participants were pathological -below the 5 th percentile; 27% of the studied participants were borderline -between the 5 th and 10 th percentile) when compared against normative data cut-offs (D'Aniello et al, 2015a). Overall, these findings suggest that cognitive estimation impairments in PD are mild, if reported at all.…”

“…The CET is widely used as a test of executive dysfunction with the generation of bizarre estimates thought to be associated with damage to processes associated with the frontal lobes of the brain (Shallice, & Evans, 1978;Smith, & Milner, 1984, 1988MacPherson, Wagner, Murphy, Bozzali, Cipolotti, & Shallice, 2014;D'Aniello, Scarpina, Albani, Castelnuovo, & Mauro, 2015a;D'Aniello, Castelnuovo, & Scarpina, 2015b).…”

Could cognitive estimation ability be a measure of cognitive reserve?

“…The first attempt to measure cognitive estimation abilities was made by Shallice and Evans ( 1978 ), who developed the Cognitive Estimation Test, consisting of a set of questions which requires appropriate reasoning abilities. The authors stressed the link between executive functions and estimation skills, finding out that patients with frontal lobe damages performed poorly on the proposed task; although the relation between cognitive estimation ability and executive functions is been a matter of discussion (Spreen and Strauss, 1998 ; Appollonio et al, 2003 ; Barabassy et al, 2010 ; D'Aniello et al, 2015 ), it has been recently supported by MacPherson et al ( 2014 ), who developed a new version of the cognitive estimation test, proving its suitability for assessing executive dysfunction; in a nutshell, it seems that the process of estimation requires a complex pattern of abilities, including executive functions.…”

“…Given these findings, we hypothesize that assessing cognitive estimation abilities might be considered a reliable strategy for measuring important aspects of cognitive reserve: in fact, it could be used as a measure of the person's body of knowledge and experiences (Della Sala et al, 2004 ), independently from aging (Della Sala et al, 2004 ; MacPherson et al, 2014 ), and—at the same time—as a sensitive instrument for assessing certain cognitive domains such as working memory and semantic knowledge (D'Aniello et al, 2015 ). The hypothesis that semantic knowledge is part of the cognitive estimation ability would be confirmed by studies relative to patients with Alzheimer's Disease (Della Sala et al, 2004 ; Levinoff et al, 2006 ; Barabassy et al, 2007 ; Khodarahimi and Rasti, 2011 ), Mild Cognitive Impairment (Levinoff et al, 2006 ), and Korsakoff's syndrome (Taylor and O'Carroll, 1995 ; Brand et al, 2003 ), in which higher amount of errors in the estimation process comparing to healthy groups were reported.…”