alien hand syndrome ( ahs ) is a rare clinical syndrome ; using the mayo clinic medical records linkage system , graff - radford et al ( 1 ) identified 150 patients with alien limbs within the department of neurology between january 1 , 1996 , and july 11 , 2011 . numerous medical and surgical conditions can cause ahs , such as cerebral infarction , cerebral hemorrhage , corticobasal degeneration , epilepsia partialis continua , alzheimer 's disease , progressive supranuclear palsy and creutzfeldt - jakob disease ( 29 ) . however , there are few reports about the pharmacologic or rehabilitation treatment of ahs . experience with pharmacologic treatment of ahs has been limited to platelet aggregation inhibitors ( 10,11 ) . in addition , the rehabilitation treatment of ahs is lacking in the literature ( 1214 ) . pooyania et al ( 14 ) identified that being educated about the diagnosis of ahs and the use of compensatory strategies ( visualization , distraction of affected limb and maintaining a slow / steady pace during activities ) decreased the frequency of patient 's ahs movements ( 14 ) . ahs can be divided into three variants , including the frontal , callosal and posterior ahs subtypes ( 5,15 ) . the callosal subtype is characterized by intermanual conflict ( antagonizing movements of the two hands ) , mostly due to the disconnection between the two cerebral hemispheres ( 16 ) . the blood supply to the corpus callosum is ample ; thus , infraction in this area is rare . the present study reports a case of callosal - subtype ahs presenting following corpus callosum infarction . in addition , the current case was compared with a collection of 31 previously reported cases of ahs that were caused by callosal infarction . a 56-year - old woman presented at the yantai yuhuangding hospital ( yantai , china ) in november 2011 with involuntary and autonomous activity of the right hand that persisted for 1 month , without apparent cause . for instance , the patient 's right hand took off her clothing while she attempted to dress with the left hand . she had a history of hypertension , coronary artery disease and type 2 diabetes mellitus , but no substance abuse history , including smoking and drinking . in addition , an ophthalmic examination failed to reveal any abnormalities , whereas a slightly superficial right nasolabial fold was detected . muscle tension was normal , with level-5 muscle force in the right upper extremity and level-4 in the right lower extremity ( 17 ) . sensory , finger - to - nose and left heel - knee - shin tests were normal . however , the heel - knee - shin test on the right side was unsuccessful . the mini - mental state examination ( mmse ) score was 30 ( 18 ) . doppler color imaging demonstrated atherosclerotic plaques in bilateral carotid arteries and increased resistance in bilateral vertebral arteries . cranial magnetic resonance imaging ( mri ) displayed long t1 and t2 signals , as well as high signals on diffusion weighted imaging ( dwi ) , in the body and splenium of the left corpus callosum ( fig . brain magnetic resonance angiography ( mra ) 3 days following admission revealed extensive atherosclerosis and intermittent visualization of the basilar artery ( fig . cerebral digital subtraction angiography ( dsa ) of the right or left internal carotid artery showed the opening of the corresponding posterior communicating artery . furthermore , bilateral posterior cerebral arteries and basilar artery apex were visualized . the left anterior cerebral artery and left pericallosal arteries appeared faint . the right vertebral artery was narrow , and the distal segment of the intracranial branch was occluded . in addition , the intracranial branch of the left vertebral artery and basilar artery was significantly narrowed ( fig . the characteristic features of callosal ahs reported in the present patient included involuntary autonomous movement , and intermanual conflict . infarction of the corpus callosum was clearly demonstrated in mri scans , while mra and dsa revealed multiple lesions in the feeding arteries . the patient was treated with aspirin enteric coated tablets ( 100 mg , qd ; bayer ag , leverkusen , germany ) atorvastatin calcium ( 20 mg , qn ; pfizer ) , amlodipine besylate tablets ( 5 mg , qd ; pfizer , inc . , new york , ny , usa ) and metformi ( 500 mg , bid ; bristol - myers squibb , new york , ny , usa ) during the 2-week hospital stay , and continued to receive the same treatment until the last visit in march 2015 . frontal ahs is characterized by forced grasping of objects and impulsive reaching and groping movements toward nearby objects within the visual field . this type of ahs is typically caused by lesions located in the anterior corpus callosum , the supplementary motor area , the anterior cingulate gyrus and the medial prefrontal cortex of the dominant hemisphere . by contrast , callosal ahs typically results from a callosal lesion and is characterized primarily by intermanual conflict and apraxia of the non - dominant limb ( 5 ) . posterior ahs is characterized by the feeling of an alien hand and left hemianesthesia , which lesions primarily in the cortex or subcortical structures , such as the thalamus , parietal lobe and medial temporal lobe that are supplied by the posterior cerebral artery ( 10,12,13,15 ) . the current study reported a case with characteristic features of callosal ahs , including involuntary autonomous movement , as well as intermanual conflict . infarction of the corpus callosum was clearly demonstrated according to the imaging results . in the present study , a search of the pubmed database ( www.ncbi.nlm.nih.gov/pubmed ) was performed ( keyword , alien hand syndrome ) in order to identify previous ahs cases presenting after callosal infraction . the search yielded 23 studies reporting 31 cases of ahs following callosal infarction between 1990 and 2014 ( 5,1940 ) . these callosal infarction cases were divided into simple corpus callosum infarction and complex corpus callosum infarction . simple corpus callosum infarction was defined as infarction occurring in the corpus callosum alone ; complex corpus callosum infarction was defined as corpus callosum with involvement of other brain sites . the search yielded a total of 31 previous ahs cases , with 7 cases of simple corpus callosum infarction ( 22.6% ) and 24 cases of complex corpus callosum infarction ( 77.4% ) . as shown in table i , the corpus callosum was affected on the left side in 10 out of the 31 cases ( 5,19,2530 ) and on the right side in 17 cases ( 20,21,2527,3140 ) . both sides of the corpus callosum were affected in 4 cases ( 20,2224 ) , all of which presented simple corpus callosum infarction ( table i ) . in complex corpus callosum infarction cases , the majority of lesion sites included the medial frontal cortex ( 16/24 ; 66.7% ) , the anterior cingulate gyrus ( 7/24 ; 29.2% ) and the supplementary motor cortex ( 3/24 ; 12.5% ) . major ahs symptoms included intermanual conflict ( 19/31 ; 61.3% ) , grasp reflect ( 19/31 ; 61.3% ) and alien hand signs ( 3/24 ; 12.5% ) . among the 7 patients with simple corpus callosum infarction , intermanual conflict occurred in 6 cases ( 85.7% ) , while grasp reflex was seen in 2 cases ( 28.5% ) . among the 24 patients with complex corpus callosum infarction , intermanual conflict was reported in 13/24 ( 54.2% ) patients , while grasp reflex was observed in 17 cases ( 70.8% ) . within the 17 grasp reflex patients , 14 ( 82.3% ) had infarction at the medial frontal cortex , cingulate gyrus or supplementary motor cortex . in addition , 2/24 ( 8.3% ) complex corpus callosum infarction cases were reported to experience involuntary masturbation . as shown in table ii , 16 ( 51.6% ) ( 19,24,25,27,3033 , 3538 ) out of the 31 included cases presented disappearance or significant alleviation of ahs symptoms during the follow - up ( between several days and 15 months ) , while no improvement was observed in 4 cases ( 5,21,27,34 ) for at least 6 months . in the remaining 11 cases ( 20,22,23,25,26,28,29,39,40 ) , in general , the literature search revealed that the lesion was complex in the majority ( 77.4% ) of cases . intermanual conflict was more common in simple corpus callosum infarction patients ( 85.7% ) , and grasp reflex was more frequently reported in complex corpus callosum infarction patients ( 70.8% ) . involuntary masturbation seems to be unique to infarction of the right anterior corpus callosum ( 37,38 ) . table i also suggests that the right hemisphere is more frequently involved , since the right and left sides of the corpus callosum were affected in 17 and 10 patients , respectively . the corpus callosum is a fiber plate that conveys information between the two cerebral hemispheres ( 41 ) . callosal ahs putatively arises from failure in connection between the motor area and the supplementary motor area in the two cerebral hemispheres ( 16,23 ) . mixed ahs has been also reported following corpus callosum infarction ( 24 ) , in which the symptoms include intermanual conflict ( as in callosal ahs ) , feeling of an alien hand and hemianesthesia ( as in posterior ahs that involves the thalamus , parietal lobe or medial temporal lobe ) ( 10,12,13,15 ) . i indicates that infarction of the corpus callosum typically occurs with lesions to other sites , including the medial frontal cortex , anterior cingulate gyrus and supplementary motor cortex . similar to the genu and body of the corpus callosum , these regions all receive blood supply from the anterior cerebral artery . by contrast , the splenium of the corpus callosum receives blood from the posterior cerebral artery ( 42 ) . infarction at the splenium of the corpus callosum is reportedly caused by embolism , whereas atherosclerotic cerebral infarction is the more common form of infarction in the genu and body of the corpus callosum ( 43 ) . the corpus callosum receives blood supply from the anterior and the posterior cerebral arteries with extensive anastomosis , and thus is rarely affected by infarction ( 42 ) . in the present case , mra and cerebral angiography revealed extensive atherosclerosis throughout the intracranial vasculature , notably in the left anterior cerebral and the vertebral basilar arteries . these imaging findings suggested the presence of atherosclerotic lesions in the anterior and posterior circulation . ahs tends to be transient in patients with partial loss of the corpus callosum genu and splenium ; in addition , patients with unilateral callosal lesions may regain connectivity between the two hemispheres if the remaining corpus callosum is functional ( 44 ) . permanent ahs may develop when the infarction involves two thirds of the anterior corpus callosum ( 45 ) . quick recovery was noticed following antiplatelet therapy in the present case , suggesting that the remaining corpus callosum may have compensated for the lesioned site , and that connectivity between the bilateral cerebral hemispheres was re - established . in conclusion , the present study reported a prototypic case of callosal ahs , which was apparently caused by compromised anterior and posterior circulation . a notable issue in this case is insufficient blood supply of the vertebra - basilar arteries and the left anterior cerebral artery . this finding highlights the need for comprehensive investigation of the cerebral vasculature in patients with ahs caused by infarction of the corpus callosum .
alien hand syndrome ( ahs ) is characterized by involuntary and autonomous activity of the affected limbs , and consists of the frontal , callosal and posterior ahs variants . 
 the callosal subtype , resulting from damage to the corpus callosum , frequently features intermanual conflict . however , infarction of the corpus callosum is rare due to abundant blood supply . 
 the present study reported a case of ahs ( callosal subtype , in the right hand ) caused by callosal infarction . 
 infarction of the left corpus callosum was confirmed with magnetic resonance imaging . 
 in addition , magnetic resonance angiography and digital subtraction angiography examinations revealed multiple lesions in the feeding arteries . 
 subsequent to antiplatelet therapy for 2 weeks following admission , the patient gradually recovered . 
 furthermore , the current study reviewed 31 previously reported cases of ahs following callosal infarction in the literature .