Anosognosia

This book proposes a novel and rigorous explanation of consciousness. It argues that the study of an aspect of our self-consciousness known as the ‘feeling of embodiment’ teaches us that there are two distinct phenomena to be targeted by an explanation of consciousness. First is an explanation of the phenomenal qualities – 'what it is like' – of the experience; and second is the subject's awareness of those qualities. Glenn Carruthers explores the phenomenal qualities of the feeling of embodiment using (...) the tools of quality spaces, as well as the subject's awareness of those qualities as a functionally emergent property of various kinds of processing of these spaces. Where much recent work on consciousness focuses on visual experience, this book rather draws evidence from the study of self-consciousness. Carruthers argues that in light of recent methodological discoveries, awareness must be explained in terms of the organization of multiple cognitive processes. The book offers an explanation of anomalous body representations and, from that, poses a more general theory of consciousness. Ultimately this book creates a hybrid account of consciousness that explains phenomenology and awareness using different tools. It will be of great interest to all scholars of psychology and philosophy as well as anyone interested in exploring the intricacies of how we experience our bodies, what we are and how we fit into the world. -/- . (shrink)

Currently, the number of patients diagnosed with impaired self-awareness of their own deficits after brain injury—anosognosia— is increasing. One reason is a growing understanding of this multifaceted phenomenon. Another is the development and accessibility of alternative measurements that allow more detailed diagnoses. Anosognosia can adversely affect successful rehabilitation, as often patients lack confidence in the need for treatment. Planning such treatment can become a complex process full of ethical dilemmas.To date, there is no systematic way to deal with different aspects (...) of anosognosia rehabilitation planning. This is the first article to present a framework for ethical decision making in establishing rehabilitation plans that are focused on increasing patients’ self-awareness of their own deficits after brain injury. It concentrates especially on addressing the ethical dilemmas that may arise, and describes stepwise procedures that can be applied to distinct theoretical approaches, as well as diagnostic and rehabilitation methods. To show the flexibility of the use of this framework, alternative approaches are discussed. (shrink)

Somatoparaphrenia is a pathology of self characterized by the sense of alienaton from parts of one’s body. It is usually construed as a kind of delusional disorder caused by extensive right hemisphere lesions. Lesions in the temporoparietal junction are common in somatoparaphrenia but deep cortical regions (for example, the posterior insula) and subcortical regions (for example, the basal ganglia) are also sometimes implicated (Valler and Ronschi 2009). Patients are often described as feeling that a limb belongs to another person and (...) thus attribute ownership of the limb and bodily sensation to someone else. There is also some question as to whether or not the higher-order thought (HOT) theory of consciousness can plausibly account for the depersonalization psychopathology of somatoparaphrenia (Liang and Lane 2009, Rosenthal 2010, Lane and Liang 2010). Liang and Lane argue that it cannot. The HOT theory of consciousness says that what makes a mental state a conscious mental state is that it is the target of a HOT to the effect that “I am in mental state M” (Rosenthal 2005, Gennaro 2012). When the HOT is itself is unconscious, the conscious state is still outer-directed. When the HOT is conscious, we have introspection and so the conscious thought is directed at the mental state. In section I, I briefly review the previous exchange between Lane and Liang and David Rosenthal. In section II, I further explore somatoparaphrenia and the nature of delusion while offering a number of additional replies to Lane and Liang. In section III, I examine the central notions of “mental state ownership” and “self-concepts” in an effort to account especially for the depersonalization aspect of somatoparaphrenia against the background of HOT theory. In section IV, I argue that to the extent that somatoparaphrenia casts doubt on the notion that some thoughts are “immune to error through misidentification” (IEM), the most fundamental aspect of IEM is still consistent with HOT theory. Overall, I argue that HOT theory is left unscathed by the pheneomenon of somatoparaphrenia and can even help to explain what happens in these cases. (shrink)

The traditional conception of self-deception takes it for an intrapersonal form of interpersonal deception. However, since the same subject is at the same time deceiver and deceived, this means attributing the agent a pair of contradictory beliefs. In the course of defending a deflationary conception of self-deception, Mele [1997] has challenged traditionalists to present convincing evidence that there are cases of self-deception in which what he calls the dual belief-requirement is satisfied. Levy [2009] has responded to this challenge affirming that (...) there is at least one real cases of self-deception that meets this requirement, namely, that of anosognosia. In this family of conditions, the patient apparently believes that there is nothing wrong with her while, at the same time, providing behavioral cues that indicate that the patient is somehow aware of his disease. If Levy is right, then traditionalism about self-deception could be vindicated, after having been widely abandoned due to its need to postulate exotic mental processes in order to make sense of the attribution of contradictory beliefs. In this paper, I assess whether Levy’s response to Mele’s challenge is successful by analyzing his interpretation of the empirical evidence to which he appeals. Finally, I attack the cogency of the underlying commitments about the nature of folk psychology to which one is required to defer in order to draw from conflicting evidence the attribution of contradictory beliefs. (shrink)

The study of anosognosia has witnessed an unprecedented increase in interest over the last 20 years. This has resulted in numerous empirical investigations as well as theoretical writings on the nature of human consciousness and how disorders of the brain may influence the person's subjective awareness of a disturbed neurological or neuropsychological function. This edited text summarizes many of the advances that have taken place in the field of anosognosia. It reviews research findings on anosognosia for hemiplegia following stroke, Anton's (...) syndrome, and a variety of disorders in which impaired self-awareness is common. It also provides suggestive guidelines for the management and rehabilitation of persons who have anosognosia or impaired self-awareness. (shrink)

Anosognosia for hemiplegia is a lack of awareness about paralysis following stroke. Recent explanations use a ‘forward model’ of movement to suggest that AHP patients fail to register discrepancies between internally- and externally-generated sensory information. We predicted that this failure would impair the ability to recall from memory whether information is internally- or externally-generated . Two experiments examined this prediction. Experiment 1 demonstrated that AHP patients exhibit a reality monitoring deficit for non-motor information , whilst hemiplegic controls without anosognosia perform (...) like age-matched healthy volunteers . Experiment 2 explored if this deficit occurs when AHP patients discriminate performed, imagined, or observed movement. Results showed impaired reality monitoring for movements in AHP and nonAHP patients relative to HVs. Findings suggest that reality monitoring processes not directly related to movement, together with a failure to reality monitor movements, contribute to the pathogenesis of AHP. (shrink)

This paper reviews the literature concerning the neural correlates of the self, the relationship between self and memory and the profile of memory impairments in Alzheimer’s disease and explores the relationship between the preservation of the self and anosognosia in this condition. It concludes that a potential explanation for anosognosia in AD is a lack of updating of personal information due to the memory impairments characteristic of this disease. We put forward the hypothesis that anosognosia is due in part to (...) the “petrified self.”. (shrink)

The sense of embodiment is vital for self recognition. An examination of anosognosia for hemiplegia—the inability to recognise that one is paralysed down one side of one’s body—suggests the existence of ‘online’ and ‘offline’ representations of the body. Online representations of the body are representations of the body as it is currently, are newly constructed moment by moment and are directly “plugged into” current perception of the body. In contrast, offline representations of the body are representations of what the body (...) is usually like, are relatively stable and are constructed from online representations. This distinction is supported by an analysis of phantom limb—the feeling that an amputated limb is still present—phenomena. Initially it seems that the sense of embodiment may arise from either of these types of representation; however, an integrated representation of the body seems to be required. It is suggested information from vision and emotions is involved in generating these representations. A lack of access to online representations of the body does not necessarily lead to a loss in the sense of embodiment. An integrated offline representation of the body could account for the sense of embodiment and perform the functions attributed to this sense. (shrink)

Currently, one of the most influential theories of consciousness is Rosenthal's version of higher-order-thought (HOT). We argue that the HOT theory allows for two distinct interpretations: a one-component and a two-component view. We further argue that the two-component view is more consistent with his effort to promote HOT as an explanatory theory suitable for application to the empirical sciences. Unfortunately, the two-component view seems incapable of handling a group of counterexamples that we refer to as cases of radical confabulation. We (...) begin by introducing the HOT theory and by indicating why we believe it is open to distinct interpretations. We then proceed to show that it is incapable of handling cases of radical confabulation. Finally, in the course of considering various possible responses to our position, we show that adoption of a disjunctive strategy, one that would countenance both one-component and two-component versions, would fail to provide any empirical or explanatory advantage. (shrink)

Anosognosia is literally ‘unawareness of or failure to acknowledge one’s hemi- plegia or other disability’ (OED). Etymology would suggest the meaning ‘lack of knowledge of disease’ so that anosognosia would include any denial of impairment, such as denial of blindness (Anton’s syndrome). But Babinski, who introduced the term in 1914, applied it only to patients with hemiplegia who fail to acknowledge their paralysis. Most commonly, this is failure to acknowledge paralysis of the left side of the body following damage to (...) the right hemisphere of the brain. In this paper, we shall mainly be concerned with anosognosia for hemiplegia. But we shall also use the term ‘anosognosia’ in an inclusive way to encompass lack of knowledge or acknowledgement of any impairment. Indeed, in the construction ‘anosognosia for X’, X might even be anosognosia for some Y. (shrink)

There are researchers in cognitive science who use clinical and experimental evidence to draw some rather skeptical conclusions about a central feature of our conscious experience, its unity. They maintain that the examination of clinical phenomena reveals that human consciousness has a much more fragmentary character than the one we normally attribute to it. In the article, these claims are questioned by examining some of the clinical studies on the deficit of anosognosia. I try to show that these studies support (...) a moderate sense of the unity of reflexive consciousness. (shrink)

Patients with right parietal lesions often deny their paralysis , but do they have "tacit" knowledge of their paralysis? I devised three novel tests to explore this. First, the patients were given a choice between a bimanual task vs a unimanual one . They chose the former on 17 of 18 trials and, surprisingly, showed no frustration or learning despite repeated failed attempts. I conclude that they have no tacit knowledge of paralysis . Second, I used a "virtual reality box" (...) to convey the optical illusion to the patient that she was moving her paralyzed left hand up and down to the rhythm of a metronome, and yet she showed no sign of surprise. Third, I irrigated patient BM′s left ear canal with cold water, a procedure that is known to shift that patient′s spatial frame of reference by stimulating the vestibular system. Surprisingly, this allowed her "repressed" memory of paralysis to come to the surface; she said she had been paralyzed continuously for several days. I suggest that the vestibular stimulation produces these remarkable effects by mimicking REM sleep. These patients also emply a whole arsenal of grossly exaggerated Freudian "defense mechanisms" to account for their paralysis. To explain this, I propose that in normal individuals the left hemisphere ordinarily deals with small, local anomalies by trying to impose consistency but, when the anomaly exceeds threshold, an interaction with the right hemisphere forces a "paradigm shift". A failure of this process, in patients with right hemisphere damage, might partially account for anosognosia. Finally, I present a new conceptual framework that may help link several psychological and neurological phenomena such as Freudian defense mechanisms, vestibular stimulation, anosognosia, memory repression, visual illusions, anterograde amnesia, REM sleep, dreaming, and humor. (shrink)

Block's P-/A-consciousness distinction rules out P's involving a specific kind of cognitive access and commits him to a “strong” Pconsciousness. This not only confounds plausible research in the area but betrays an anosognosia about Wittgenstein's diagnosis about our philosophical “introspection” of mysterious inner processes.

This volume provides, for the first time, multidisciplinary perspectives on the problem of awareness of deficits following brain injury.