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Delay discounting in mild cognitive impairment

Publication . Coelho, Sara; Guerreiro, Manuela; Chester, Catarina Carapeto da Silva; Silva, Dina Lúcia Gomes da; Maroco, João; Paglieri, Fabio; Mendonça, Alexandre de

Introduction : Patients with mild cognitive impairme nt (MCI) may make suboptimal decisions particularly in complex situations, and thi s could be due to temporal discounting, the tendency to prefer immediate rewards over delayed but larger rewards. The present study proposes to evaluate intertemporal prefere nces in MCI patients as compared to healthy controls. Method : Fifty-five patients with MCI and 57 h ealthy controls underwent neuropsy- chological evaluation and a delay discounting questionnaire, which evaluates three para- meters: hyperbolic discounting ( k ), the percentage of choices for delayed and later rewards (%LL), and response consistency (Acc). Results : No significant differences were found in the delay discounting questionnaire between MC I patients and controls for the three reward sizes considered, small, medium, and large, using both k and %LL parameters. There were also no differences in the response consistency, Acc, between the two groups. Conclusions : Patients with MCI perform similarly to healthy controls in a delay discounting task. Memory deficits do not notably affect intertemporal preferences.

2016Journal article

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Time perception in mild cognitive impairment: Interval length and subjective passage of time

Publication . Coelho, Sara; Guerreiro, Manuela; Chester, Catarina Carapeto da Silva; Silva, Dina Lúcia Gomes da; Maroco, João; Coelho, Miguel; Paglieri, Fabio; Mendonça, Alexandre de

Objectives: Patients with mild cognitive impairment (MCI) may have difficulties in time perception, which in turn might contribute to some of their symptoms, especially memory deficits. The aim of this study was to evaluate perception of interval length and subjective passage of time in MCI patients as compared to healthy controls. Methods: Fifty-five MCI patients and 57 healthy controls underwent an experimental protocol for time perception on interval length, a questionnaire for the subjective passage of time and a neuropsychological evaluation. Results: MCI patients presented no changes in the perception of interval length. However, for MCI patients, time seemed to pass more slowly than it did for controls. This experience was significantly correlated with memory deficits but not with performance in executive tests, nor with complaints of depression or anxiety. Conclusions: Memory deficits do not affect the perception of interval length, but are associated with alterations in the subjective passage of time.

2016-08Journal article

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Mental time travel in mild cognitive impairment

Publication . Coelho, Sara; Guerreiro, Manuela; Chester, Catarina; Silva, Dina Lúcia Gomes da; Marôco, J. P.; Paglieri, Fabio; Mendonça, Alexandre de

Introduction: Mental Time Travel (MTT) is the people's ability to remember themselves in the past and to imagine themselves in the future, and influence important life domains such as making decisions and planning future actions. It is widely recognized that patients with aMCI have deficits in episodic memory, but they also show impairments in semantic memory. It has been controversial whether MTT tasks are disturbed in aMCI mainly in relation to internal details related to episodic information, or external details, representing semantic and other extraneous information. The present study assessed whether patients with aMCI are affected in MTT regarding generation of internal details and external details, in past and future dimensions. Furthermore, it analyzed production in individual detail categories (internal: event details, thought/emotion, place, time, perceptual; external: extraneous events, semantic, other, repetitions). Method: Twenty-nine patients with aMCI and 29 healthy controls underwent a MTT task based on an Autobiographical Interview, where they had to generate past and future events in response to cue words. Transcriptions were segmented and classified into internal detail categories and external detail categories, and composite scores were obtained. Results: Patients with aMCI could globally produce significantly less details than controls. Similar to controls, patients with aMCI produced more internal details than external details, had more difficulty in generating details regarding the future as compared to the past, and scored higher in the detail categories event details and thought/emotion which represent internal detail types. Conclusions: Patients with aMCI showed widespread deficits in MTT, presumably reflecting deficiencies in the complex and multiple cognitive abilities required for MTT tasks.

2019Journal article

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