Somatoparaphrenia is a type of monothematic delusion where one denies ownership of a limb or an entire side of one's body. Even if provided with undeniable proof that the limb belongs to and is attached to their own body, the patient produces elaborate confabulations about whose limb it really is or how the limb ended up on their body.[1][2] In some cases, delusions become so elaborate that a limb may be treated and cared for as if it were a separate being.[1]
| Somatoparaphrenia | |
|---|---|
| Specialty | Psychiatry |
Somatoparaphrenia differs from a similar disorder, asomatognosia, which is characterized as loss of recognition of half of the body or a limb, possibly due to paralysis or unilateral neglect.[3] For example, asomatognosic patients may mistake their arm for the doctor's. However, they can be shown their limb and this error is temporarily corrected.[1]
Somatoparaphrenia has been reported to occur predominantly in the left arm of one's body,[4] and it is often accompanied by left-sided paralysis and anosognosia (denial or lack of awareness) of the paralysis. The link between somatoparaphrenia and paralysis has been documented in many clinical cases,[5] and while the question arises as to whether paralysis is necessary for somatoparaphrenia to occur, it has been confirmed that anosognosia is not necessary, since cases of somatoparaphrenia and paralysis with no anosognosia have been documented.[6]
History
editCases of somatoparaphrenia had been described since the end of the nineteenth century, but it wasn't until 1942 that Gerstman introduced the term somatoparaphrenic symptoms, defined as illusions or distortions concerning the perception of the affected limb or side of the body, which is believed or experienced as absent. The term was coined from the Greek: παρά, para + φρεν, phren, meaning "against the mind" and σώμα, soma (stem somat–) referring to the "body"; therefore, somatoparaphrenia is defined as a bodily delusion.[7]
The main manifestation of somatoparaphrenia is the feeling of disownership of the contralesional body; the belief that contralesional body parts do not belong to them but to another person.[7] Reinstatement of ownership by third-person perspective does not permanently abolish somatoparaphrenia suggesting that the subjective sense of body ownership remains dominated by an impaired first-person representation of the body that cannot be updated.[8]
Causes
editIt has been suggested that damage to the posterior cerebral regions (temporoparietal junction) of the cortex may play a significant role in the development of somatoparaphrenia.[9][10] However, more recent studies have shown that damage to deep cortical regions such as the posterior insula[11] and subcortical structures such as the basal ganglia,[12] the thalamus and the white matter connecting the thalamus to the cortex may also play a significant role in the development of somatoparaphrenia.[13] It has also been suggested that involvement of deep cortical and subcortical grey structures of the temporal lobe may contribute to reduce the sense of familiarity experienced by somatoparaphrenic patients for their paralyzed limb.[13]
Treatment
editOne form of treatment that has produced a more integrated body awareness is mirror therapy, in which the individual who denies that the affected limb belongs to their body looks into a mirror at the limb. Patients looking into the mirror state that the limb does belong to them; however body ownership of the limb does not remain after the mirror is taken away.[14]
See also
editReferences
edit- ^ a b c Feinberg T.; Venneri A.; Simone A.M.; et al. (2010). "The neuroanatomy of asomatognosia and somatoparaphrenia". Journal of Neurology, Neurosurgery & Psychiatry. 81 (3): 276–281. doi:10.1136/jnnp.2009.188946. PMID 19778911. S2CID 4931879.
- ^ Bottini G.; Bisiach E.; Sterzi R.; Vallar G. (2002). "Feeling touches in someone else's hand". NeuroReport. 13 (2): 249–252. doi:10.1097/00001756-200202110-00015. PMID 11893919. S2CID 32287566.
- ^ Vallar G., Ronchi R. (2009). "Somatoparaphrenia: a body delusion. A review of the neuropsychological literature". Experimental Brain Research. 192 (3): 533–551. doi:10.1007/s00221-008-1562-y. PMID 18813916. S2CID 206924931.
- ^ Coltheart M (2005). "Delusional belief". Australian Journal of Psychology. 57 (2): 72. doi:10.1080/00049530500125082.
- ^ Vallar G., Ronchi R. (2009). "Somatoparaphrenia: A body delusion. A review of the neuropsychological literature". Experimental Brain Research. 192 (3): 533–51. doi:10.1007/s00221-008-1562-y. PMID 18813916. S2CID 206924931.
- ^ Invernizzi P, Gandola M, Romano D, Zapparoli L, Bottini G, Paulesu E (2013). "What is mine? Behavioral and anatomical dissociations between somatoparaphrenia and anosognosia for hemiplegia". Behav Neurol. 26 (1–2): 139–50. doi:10.1155/2013/548467. PMC 5213125. PMID 22713395.
- ^ a b Ronchi, Roberta; Park, Hyeong-Dong; Blanke, Olaf (2018-01-01), Vallar, Giuseppe; Coslett, H. Branch (eds.), "Chapter 15 - Bodily self-consciousness and its disorders", Handbook of Clinical Neurology, The Parietal Lobe, 151, Elsevier: 313–330, doi:10.1016/B978-0-444-63622-5.00015-2, ISBN 978-0-444-63622-5, PMID 29519466, retrieved 2024-01-28
- ^ Fotopoulou, Aikaterini; Jenkinson, Paul Mark; Tsakiris, Manos; Haggard, Patrick; Rudd, Antony; Kopelman, Michael D. (December 2011). "Mirror-view reverses somatoparaphrenia: dissociation between first- and third-person perspectives on body ownership". Neuropsychologia. 49 (14): 3946–3955. doi:10.1016/j.neuropsychologia.2011.10.011. ISSN 1873-3514. PMID 22023911.
- ^ Feinberg T. E.; Haber L. D.; Leeds N.E. (1990). "Verbal asomatognosia". Neurology. 40 (9): 1391–1394. doi:10.1212/wnl.40.9.1391. PMID 2392224. S2CID 35409449.
- ^ Feinberg T. E.; Roane D. M.; Ali J. (2000). "Illusory limb movements in anosognosia for hemiplegia". J Neurol Neurosurg Psychiatry. 68 (4): 511–513. doi:10.1136/jnnp.68.4.511. PMC 1736869. PMID 10727491.
- ^ Cereda C.; Ghika J.; Maeder P.; Bogousslavsky J. (2002). "Strokes restricted to the insular cortex". Neurology. 59 (12): 1950–1955. doi:10.1212/01.wnl.0000038905.75660.bd. PMID 12499489. S2CID 22115202.
- ^ Healton E. B.; Navarro C.; Bressman S.; Brust J. C. (1982). "Subcortical neglect". Neurology. 32 (7): 776–778. doi:10.1212/wnl.32.7.776. PMID 7201116. S2CID 219207359.
- ^ a b Gandola M, Invernizzi P, Sedda A, Ferré ER, Sterzi R, Sberna M, Paulesu E, Bottini G (Oct 2012). "An anatomical account of somatoparaphrenia". Cortex. 48 (9): 1165–78. doi:10.1016/j.cortex.2011.06.012. PMID 21774922. S2CID 37732776.
- ^ Fotopoulou A., Jenkinson P.M., Tsakiris M., Haggard P., Rudd A., Kopelman M.D. (2011). "Mirror-view reverses somatopharaphrenia: Dissociation between first- and third-person perspectives on body ownership". Neuropsychologia. 49 (14): 3946–3955. doi:10.1016/j.neuropsychologia.2011.10.011. PMID 22023911. S2CID 25892919.
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