title: Anosognosia as motivated unawareness: the 'defence' hypothesis revisited.
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.
authors.affiliation: Centre for Cognitive Neuroscience, School of Psychology, Bangor University, Wales, UK. Electronic address: o.turnbull@bangor.ac.uk.
authors.forename: Oliver H
authors.initials: OH
authors.lastname: Turnbull
authors.affiliation: Clinical, Educational and Health Psychology, Division of Psychology and Language Sciences, University College London, UK.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Fotopoulou
authors.affiliation: Department of Psychology, University of Cape Town, South Africa.
authors.forename: Mark
authors.initials: M
authors.lastname: Solms
mesh_terms: D000377:Agnosia / Q000523:psychology*; D001364:Awareness / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004644:Emotions / Q000502:physiology; D006429:Hemiplegia / Q000523:psychology*; D006801:Humans; D009042:Motivation / Q000502:physiology*
keywords: Anosognosia; Defence; Egocentric spatial cognition; Emotion; Hemiplegia; Motivation