CONCEPTUAL PROBLEMS: NEGLECT VERSUS MISREPRESENTATION AND IRRATIONAL BELIEFS
A satisfactory definition of anosognosia per se is perhaps impossible, attributable to the fact that the term anosognosia, rather than referring to a truly distinct symptom, may be (and has indeed been) used to denote aspects of patients' behavior in relation to their illness that are heterogeneous in appearance and unlikely to depend on a specific set of causes exclusively related to them.
Recall Seneca's observation that Harpastes "nescit esse se caecum" (she does not know she is blind). Even assuming that she had never denied blindness verbally, the truth of Seneca's statement seems to be irrefutable given the behavior she displayed after the onset of her illness. However, patients who verbally deny their hemiplegia usually do not object to being confined to bed. In contrast,patients who verbally admit of paralysis on one side may attempt to stand andwalk or ask for tools they are patently unable to handle as they did prior to theirillness. Anton (1899) used the term "dunkle Kenntnis" (dim knowledge) withreference to such instances; it seems, however, more appropriate to talk of dissociationof knowledge (see Chapters 11 and 14).In other cases-indeed, in most cases-unawareness of hemiplegia or hemianopia,whatever the basis on which it is inferred, is clearly secondary to the fact that patients ignore one side of their body and environment. Other cases exist in which deficient knowledge of illness is inferred from the apparent lack of adequate emotional reactions, the condition Babinski (1914) named "anosodiaphoria."
These definitional issues cease to be a problem if anosognosia related to hemiplegia and hemianopia-rather than being treated as a separate subject-viewed as one of the peculiar symptoms of a circumscribed brain lesion disrupting a single substrate of cognitive activities. Such concepts as attention, representation, beliefs, and consciousness are related, within a circumscribed domain of spatial reference, to this area. This view is defended in a later section of this chapter.
Recall Seneca's observation that Harpastes "nescit esse se caecum" (she does not know she is blind). Even assuming that she had never denied blindness verbally, the truth of Seneca's statement seems to be irrefutable given the behavior she displayed after the onset of her illness. However, patients who verbally deny their hemiplegia usually do not object to being confined to bed. In contrast,patients who verbally admit of paralysis on one side may attempt to stand andwalk or ask for tools they are patently unable to handle as they did prior to theirillness. Anton (1899) used the term "dunkle Kenntnis" (dim knowledge) withreference to such instances; it seems, however, more appropriate to talk of dissociationof knowledge (see Chapters 11 and 14).In other cases-indeed, in most cases-unawareness of hemiplegia or hemianopia,whatever the basis on which it is inferred, is clearly secondary to the fact that patients ignore one side of their body and environment. Other cases exist in which deficient knowledge of illness is inferred from the apparent lack of adequate emotional reactions, the condition Babinski (1914) named "anosodiaphoria."
These definitional issues cease to be a problem if anosognosia related to hemiplegia and hemianopia-rather than being treated as a separate subject-viewed as one of the peculiar symptoms of a circumscribed brain lesion disrupting a single substrate of cognitive activities. Such concepts as attention, representation, beliefs, and consciousness are related, within a circumscribed domain of spatial reference, to this area. This view is defended in a later section of this chapter.
