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Aikaterini Fotopoulou – One of the best experts on this subject based on the ideXlab platform.

  • mentalizing the body spatial and social cognition in Anosognosia for hemiplegia
    Brain, 2016
    Co-Authors: Sahba Besharati, Stephanie J Forkel, Michael D Kopelman, Mark Solms, Paul M Jenkinson, Aikaterini Fotopoulou

    Abstract:

    Following right-hemisphere damage, a specific disorder of motor awareness can occur called Anosognosia for hemiplegia, i.e. the denial of motor deficits contralateral to a brain lesion. The study of Anosognosia can offer unique insights into the neurocognitive basis of awareness. Typically, however, awareness is assessed as a first person judgement and the ability of patients to think about their bodies in more ‘objective’ (third person) terms is not directly assessed. This may be important as right-hemisphere spatial abilities may underlie our ability to take third person perspectives. This possibility was assessed for the first time in the present study. We investigated third person perspective taking using both visuospatial and verbal tasks in right-hemisphere stroke patients with Anosognosia (n = 15) and without Anosognosia (n = 15), as well as neurologically healthy control subjects (n = 15). The anosognosic group performed worse than both control groups when having to perform the tasks from a third versus a first person perspective. Individual analysis further revealed a classical dissociation between most anosognosic patients and control subjects in mental (but not visuospatial) third person perspective taking abilities. Finally, the severity of unawareness in Anosognosia patients was correlated to greater impairments in such third person, mental perspective taking abilities (but not visuospatial perspective taking). In voxel-based lesion mapping we also identified the lesion sites linked with such deficits, including some brain areas previously associated with inhibition, perspective taking and mentalizing, such as the inferior and middle frontal gyri, as well as the supramarginal and superior temporal gyri. These results suggest that neurocognitive deficits in mental perspective taking may contribute to Anosognosia and provide novel insights regarding the relation between self-awareness and social cognition.

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  • error based training and emergent awareness in Anosognosia for hemiplegia
    Neuropsychological Rehabilitation, 2015
    Co-Authors: Valentina Moro, Michele Scandola, Cristina Bulgarelli, Renato Avesani, Aikaterini Fotopoulou

    Abstract:

    Residual forms of awareness have recently been demonstrated in subjects affected by Anosognosia for hemiplegia, but their potential effects in recovery of awareness remain to date unexplored. Emergent awareness refers to a specific facet of motor unawareness in which anosognosic subjects recognise their motor deficits only when they have been requested to perform an action and they realise their errors. Four participants in the chronic phase after a stroke with Anosognosia for hemiplegia were recruited. They took part in an “error-full” or “analysis of error-based” rehabilitative training programme. They were asked to attempt to execute specific actions, analyse their own strategies and errors and discuss the reasons for their failures. Pre- and post-training and follow-up assessments showed that motor unawareness improved in all four patients. These results indicate that unsuccessful action attempts with concomitant error analysis may facilitate the recovery of emergent awareness and, sometimes, of more general aspects of awareness.

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  • Anosognosia as motivated unawareness the defence hypothesis revisited
    Cortex, 2014
    Co-Authors: Oliver H. Turnbull, Aikaterini Fotopoulou, Mark Solms

    Abstract:

    Anosognosia for hemiplegia has seen a century of almost continuous research, yet a definitive understanding of its mechanism remains elusive. Essentially, anosognosic patients hold quasi-delusional beliefs about their paralysed limbs, in spite of all the contrary evidence, repeated questioning, and logical argument. We review a range of findings suggesting that emotion and motivation play an important role in Anosognosia. We conclude that Anosognosia involves (amongst other things) a process of psychological defence. This conclusion stems from a wide variety of clinical and experimental investigations, including data on implicit awareness of deficit, fluctuations in awareness over time, and dramatic effects upon awareness of psychological interventions such as psychotherapy, reframing of the emotional consequences of the paralysis, and first versus third person perspectival manipulations. In addition, we review and refute the (eight) arguments historically raised against the ‘defence’ hypothesis, including the claim that a defence-based account cannot explain the lateralised nature of the disorder. We argue that damage to a well-established right-lateralised emotion regulation system, with links to psychological processes that appear to underpin allocentric spatial cognition, plays a key role in Anosognosia (at least in some patients). We conclude with a discussion of implications for clinical practice.

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Peter P. Deyn – One of the best experts on this subject based on the ideXlab platform.

  • Functional Neural Correlates of Anosognosia in Mild Cognitive Impairment and Alzheimer’s Disease: a Systematic Review
    Neuropsychology Review, 2019
    Co-Authors: Jaime D. Mondragón, Natasha M. Maurits, Peter P. Deyn

    Abstract:

    Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used to assess the neural correlates of Anosognosia in mild cognitive impairment (MCI) and Alzheimer’s disease (AD). A systematic review of this literature was performed, following the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement, on PubMed, EMBASE, and PsycINFO databases. Twenty-five articles met all inclusion criteria. Specifically, four brain connectivity and 21 brain perfusion, metabolism, and activation articles. Anosognosia is associated in MCI with frontal lobe and cortical midline regional dysfunction (reduced perfusion and activation), and with reduced parietotemporal metabolism. Reduced within and between network connectivity is observed in the default mode network regions of AD patients with Anosognosia compared to AD patients without Anosognosia and controls. During initial stages of cognitive decline in Anosognosia, reduced indirect neural activity (i.e. perfusion, metabolism, and activation) is associated with the cortical midline regions, followed by the parietotemporal structures in later stages and culminating in frontotemporal dysfunction. Although the current evidence suggests differences in activation between AD or MCI patients with Anosognosia and healthy controls, more evidence is needed exploring the differences between MCI and AD patients with and without Anosognosia using resting state and task related paradigms.

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  • functional neural correlates of Anosognosia in mild cognitive impairment and alzheimer s disease a systematic review
    Neuropsychology Review, 2019
    Co-Authors: Jaime D. Mondragón, Peter P. Deyn, Natasha M. Maurits

    Abstract:

    Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used to assess the neural correlates of Anosognosia in mild cognitive impairment (MCI) and Alzheimer’s disease (AD). A systematic review of this literature was performed, following the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement, on PubMed, EMBASE, and PsycINFO databases. Twenty-five articles met all inclusion criteria. Specifically, four brain connectivity and 21 brain perfusion, metabolism, and activation articles. Anosognosia is associated in MCI with frontal lobe and cortical midline regional dysfunction (reduced perfusion and activation), and with reduced parietotemporal metabolism. Reduced within and between network connectivity is observed in the default mode network regions of AD patients with Anosognosia compared to AD patients without Anosognosia and controls. During initial stages of cognitive decline in Anosognosia, reduced indirect neural activity (i.e. perfusion, metabolism, and activation) is associated with the cortical midline regions, followed by the parietotemporal structures in later stages and culminating in frontotemporal dysfunction. Although the current evidence suggests differences in activation between AD or MCI patients with Anosognosia and healthy controls, more evidence is needed exploring the differences between MCI and AD patients with and without Anosognosia using resting state and task related paradigms.

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Sahba Besharati – One of the best experts on this subject based on the ideXlab platform.

  • mentalizing the body spatial and social cognition in Anosognosia for hemiplegia
    Brain, 2016
    Co-Authors: Sahba Besharati, Stephanie J Forkel, Michael D Kopelman, Mark Solms, Paul M Jenkinson, Aikaterini Fotopoulou

    Abstract:

    Following right-hemisphere damage, a specific disorder of motor awareness can occur called Anosognosia for hemiplegia, i.e. the denial of motor deficits contralateral to a brain lesion. The study of Anosognosia can offer unique insights into the neurocognitive basis of awareness. Typically, however, awareness is assessed as a first person judgement and the ability of patients to think about their bodies in more ‘objective’ (third person) terms is not directly assessed. This may be important as right-hemisphere spatial abilities may underlie our ability to take third person perspectives. This possibility was assessed for the first time in the present study. We investigated third person perspective taking using both visuospatial and verbal tasks in right-hemisphere stroke patients with Anosognosia (n = 15) and without Anosognosia (n = 15), as well as neurologically healthy control subjects (n = 15). The anosognosic group performed worse than both control groups when having to perform the tasks from a third versus a first person perspective. Individual analysis further revealed a classical dissociation between most anosognosic patients and control subjects in mental (but not visuospatial) third person perspective taking abilities. Finally, the severity of unawareness in Anosognosia patients was correlated to greater impairments in such third person, mental perspective taking abilities (but not visuospatial perspective taking). In voxel-based lesion mapping we also identified the lesion sites linked with such deficits, including some brain areas previously associated with inhibition, perspective taking and mentalizing, such as the inferior and middle frontal gyri, as well as the supramarginal and superior temporal gyri. These results suggest that neurocognitive deficits in mental perspective taking may contribute to Anosognosia and provide novel insights regarding the relation between self-awareness and social cognition.

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  • the affective modulation of motor awareness in Anosognosia for hemiplegia behavioural and lesion evidence
    Cortex, 2014
    Co-Authors: Sahba Besharati, Stephanie J Forkel, Michael D Kopelman, Mark Solms, Paul M Jenkinson, Aikaterini Fotopoulou

    Abstract:

    The possible role of emotion in Anosognosia for hemiplegia (i.e., denial of motor deficits contralateral to a brain lesion), has long been debated between psychodynamic and neurocognitive theories. However, there are only a handful of case studies focussing on this topic, and the precise role of emotion in Anosognosia for hemiplegia requires empirical investigation. In the present study, we aimed to investigate how negative and positive emotions influence motor awareness in Anosognosia. Positive and negative emotions were induced under carefully-controlled experimental conditions in right-hemisphere stroke patients with Anosognosia for hemiplegia (n = 11) and controls with clinically normal awareness (n = 10). Only the negative, emotion induction condition resulted in a significant improvement of motor awareness in anosognosic patients compared to controls; the positive emotion induction did not. Using lesion overlay and voxel-based lesion-symptom mapping approaches, we also investigated the brain lesions associated with the diagnosis of Anosognosia, as well as with performance on the experimental task. Anatomical areas that are commonly damaged in AHP included the right-hemisphere motor and sensory cortices, the inferior frontal cortex, and the insula. Additionally, the insula, putamen and anterior periventricular white matter were associated with less awareness change following the negative emotion induction. This study suggests that motor unawareness and the observed lack of negative emotions about one’s disabilities cannot be adequately explained by either purely motivational or neurocognitive accounts. Instead, we propose an integrative account in which insular and striatal lesions result in weak interoceptive and motivational signals. These deficits lead to faulty inferences about the self, involving a difficulty to personalise new sensorimotor information, and an abnormal adherence to premorbid beliefs about the body.

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