Skip to main content
NCBI home page
Philosophical Transactions of the Royal Society B: Biological Sciences logoLink to Philosophical Transactions of the Royal Society B: Biological Sciences
. 1998 Nov 29;353(1377):1903–1909. doi: 10.1098/rstb.1998.0342

Possible mechanisms of anosognosia: a defect in self-awareness.

K M Heilman 1, A M Barrett 1, J C Adair 1
PMCID: PMC1692420  PMID: 9854262

Abstract

Anosognosia of hemiplegia is of interest for both pragmatic and theoretical reasons. We discuss several neuropsychological theories that have been proposed to explain this deficit. Although for psychological reasons people might deny deficits, the denial hypothesis cannot account for the hemispheric asymmetries associated with this disorder and cannot explain why some patients might deny one deficit and recognize another equally disabling deficit. There is some evidence that faulty feedback from sensory deficits, spatial neglect and asomatognosia might be responsible for anosognosia in some patients. However, these feedback hypotheses cannot account for anosognosia in all patients. Although the hemispheric disconnection hypothesis is appealing, disconnection is probably only a rare cause of this disorder. The feedforward intentional theory of anosognosia suggests that the discovery of weakness is dependent on attempted action and some patients might have anosognosia because they do not attempt to move. We present evidence that supports this theory. The presence of one mechanism of anosognosia, however, does not preclude the possibility that other mechanisms might also be working to produce this disorder. Although a large population study needs to be performed, we suspect that anosognosia might be caused by several of the mechanisms that we have discussed. On the basis of the studies of impaired corporeal self-awareness that we have reviewed, we can infer that normal self-awareness is dependent on several parallel processes. One must have sensory feedback and the ability to attend to both one's body and the space where parts of the body may be positioned or acting. One must develop a representation of the body, and this representation must be continuously modified by expectations (feedforward) and knowledge of results (feedback).

Full Text

The Full Text of this article is available as a PDF (144.8 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adair J. C., Schwartz R. L., Na D. L., Fennell E., Gilmore R. L., Heilman K. M. Anosognosia: examining the disconnection hypothesis. J Neurol Neurosurg Psychiatry. 1997 Dec;63(6):798–800. doi: 10.1136/jnnp.63.6.798. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bisiach E., Vallar G., Perani D., Papagno C., Berti A. Unawareness of disease following lesions of the right hemisphere: anosognosia for hemiplegia and anosognosia for hemianopia. Neuropsychologia. 1986;24(4):471–482. doi: 10.1016/0028-3932(86)90092-8. [DOI] [PubMed] [Google Scholar]
  3. Breier J. I., Adair J. C., Gold M., Fennell E. B., Gilmore R. L., Heilman K. M. Dissociation of anosognosia for hemiplegia and aphasia during left-hemisphere anesthesia. Neurology. 1995 Jan;45(1):65–67. doi: 10.1212/wnl.45.1.65. [DOI] [PubMed] [Google Scholar]
  4. Carpenter K., Berti A., Oxbury S., Molyneux A. J., Bisiach E., Oxbury J. M. Awareness of and memory for arm weakness during intracarotid sodium amytal testing. Brain. 1995 Feb;118(Pt 1):243–251. doi: 10.1093/brain/118.1.243. [DOI] [PubMed] [Google Scholar]
  5. Coslett H. B., Heilman K. M. Hemihypokinesia after right hemisphere stroke. Brain Cogn. 1989 Mar;9(2):267–278. doi: 10.1016/0278-2626(89)90036-5. [DOI] [PubMed] [Google Scholar]
  6. Durkin M. W., Meador K. J., Nichols M. E., Lee G. P., Loring D. W. Anosognosia and the intracarotid amobarbital procedure (Wada test). Neurology. 1994 May;44(5):978–979. doi: 10.1212/wnl.44.5.978. [DOI] [PubMed] [Google Scholar]
  7. Dywan C. A., McGlone J., Fox A. Do intracarotid barbiturate injections offer a way to investigate hemispheric models of anosognosia? J Clin Exp Neuropsychol. 1995 May;17(3):431–438. doi: 10.1080/01688639508405134. [DOI] [PubMed] [Google Scholar]
  8. Feinberg T. E., Roane D. M., Kwan P. C., Schindler R. J., Haber L. D. Anosognosia and visuoverbal confabulation. Arch Neurol. 1994 May;51(5):468–473. doi: 10.1001/archneur.1994.00540170044015. [DOI] [PubMed] [Google Scholar]
  9. Gainotti G. Emotional behavior and hemispheric side of the lesion. Cortex. 1972 Mar;8(1):41–55. doi: 10.1016/s0010-9452(72)80026-1. [DOI] [PubMed] [Google Scholar]
  10. Geschwind N. Disconnexion syndromes in animals and man. II. Brain. 1965 Sep;88(3):585–644. doi: 10.1093/brain/88.3.585. [DOI] [PubMed] [Google Scholar]
  11. Gilmore R. L., Heilman K. M., Schmidt R. P., Fennell E. M., Quisling R. Anosognosia during Wada testing. Neurology. 1992 Apr;42(4):925–927. doi: 10.1212/wnl.42.4.925. [DOI] [PubMed] [Google Scholar]
  12. Gold M., Adair J. C., Jacobs D. H., Heilman K. M. Anosognosia for hemiplegia: an electrophysiologic investigation of the feed-forward hypothesis. Neurology. 1994 Oct;44(10):1804–1808. doi: 10.1212/wnl.44.10.1804. [DOI] [PubMed] [Google Scholar]
  13. Heilman K. M., Van Den Abell T. Right hemispheric dominance for mediating cerebral activation. Neuropsychologia. 1979;17(3-4):315–321. doi: 10.1016/0028-3932(79)90077-0. [DOI] [PubMed] [Google Scholar]
  14. Levine D. N., Calvanio R., Rinn W. E. The pathogenesis of anosognosia for hemiplegia. Neurology. 1991 Nov;41(11):1770–1781. doi: 10.1212/wnl.41.11.1770. [DOI] [PubMed] [Google Scholar]
  15. Lu L. H., Barrett A. M., Schwartz R. L., Cibula J. E., Gilmore R. L., Uthman B. M., Heilman K. M. Anosognosia and confabulation during the Wada test. Neurology. 1997 Nov;49(5):1316–1322. doi: 10.1212/wnl.49.5.1316. [DOI] [PubMed] [Google Scholar]
  16. Mark V. W., Heilman K. M. Bodily neglect and orientational biases in unilateral neglect syndrome and normal subjects. Neurology. 1990 Apr;40(4):640–643. doi: 10.1212/wnl.40.4.640. [DOI] [PubMed] [Google Scholar]
  17. McGlynn S. M., Schacter D. L. Unawareness of deficits in neuropsychological syndromes. J Clin Exp Neuropsychol. 1989 Mar;11(2):143–205. doi: 10.1080/01688638908400882. [DOI] [PubMed] [Google Scholar]
  18. Mesulam M. M., Waxman S. G., Geschwind N., Sabin T. D. Acute confusional states with right middle cerebral artery infarctions. J Neurol Neurosurg Psychiatry. 1976 Jan;39(1):84–89. doi: 10.1136/jnnp.39.1.84. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Ramachandran V. S. Anosognosia in parietal lobe syndrome. Conscious Cogn. 1995 Mar;4(1):22–51. doi: 10.1006/ccog.1995.1002. [DOI] [PubMed] [Google Scholar]
  20. Starkstein S. E., Fedoroff J. P., Price T. R., Leiguarda R., Robinson R. G. Anosognosia in patients with cerebrovascular lesions. A study of causative factors. Stroke. 1992 Oct;23(10):1446–1453. doi: 10.1161/01.str.23.10.1446. [DOI] [PubMed] [Google Scholar]
  21. Stone S. P., Patel P., Greenwood R. J., Halligan P. W. Measuring visual neglect in acute stroke and predicting its recovery: the visual neglect recovery index. J Neurol Neurosurg Psychiatry. 1992 Jun;55(6):431–436. doi: 10.1136/jnnp.55.6.431. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. TERZIAN H. BEHAVIOURAL AND EEG EFFECTS OF INTRACAROTID SODIUM AMYTAL INJECTION. Acta Neurochir (Wien) 1964;12:230–239. doi: 10.1007/BF01402095. [DOI] [PubMed] [Google Scholar]

Articles from Philosophical Transactions of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society

RESOURCES