Overview. Alien hand syndrome is a rare neurological condition that causes one hand to act on its own free will. Sometimes one leg is affected, though this isn't as ...WhatIsAlienHandSyndrome?MedicallyreviewedbyWilliamMorrison,M.D.—WrittenbyEmilyCronkleton—UpdatedonSeptember18,2018CausesSymptomsDiagnosisTreatmentFastfactsOutlookOverviewAlienhandsyndromeisarareneurologicalconditionthatcausesonehandtoactonitsownfreewill.Sometimesonelegisaffected,thoughthisisn’tascommon.Withalienhandsyndrome,thehandisn’tunderthecontrolofthemindandmovesasthoughithasitsownmind.Theaffectedhandfeelsforeigntoitsownerduringtheseepisodesandseemstomovedeliberatelytocarryouttasksthatareunintentional.Whileitcanaffectchildren,usuallyalienhandoccursinadults.It’ssometimesreferredtoasDr.Strangelovesyndrome,Strangelovianhand,oranarchichand.Whatcausesthis?Alienhandsyndromecanbecausedbyseveralfactors.Somepeopledevelopalienhandsyndromeafterastroke,trauma,ortumor.It’ssometimesassociatedwithcancer,neurodegenerativediseases,andbrainaneurysms.Alienhandsyndromeislinkedtobrainsurgeriesthatseparatethetwohemispheresofthebrain.Thismayinvolveanincisionalongthecorpuscallosum.Thecorpuscallosumdividesthebrainhemispheresandallowsforcommunicationbetweenthetwosides.Surgeriestotreatepilepsysometimesaffectthebraininthisway.Lesionshavealsobeenfoundintheanteriorcingulatecortex,posteriorparietalcortex,andsupplementarymotorcortexareasofthebraininthosewiththecondition.Brainscansshowthatpeoplewithalienhandsyndromehaveisolatedactivitiesinthecontralateralprimarymotorarea.Thisisthoughttobeduetolesionsordamageintheparietalcortex.Thisaffectsintentionalplanningsystemsandcancausespontaneousmovements.Whatarethesymptoms?Themostprominentsymptomofalienhandsyndromeistheinabilitytocontrolthehandasitactsindependently.Theaffectedhandmaymoveinvoluntarilyandperformgoal-directedtasksandactions.Thehandissaidtomovewithoutcognitivecontrolorawareness.It’sasthoughit’sbeingcontrolledbysomeoneelseorhasamindofitsown.Thehandmaytouchyourface,buttonashirt