Dear Editor, We would like to report a well-documented case of diagnostic dyspraxia as a consequence of a ruptured distal anterior cerebral artery (DACA) aneurysm. Radiological findings on tractography permit a better understanding of the physiopathology and anatomo-clinical correlations between diagnostic dyspraxia and intracranial hemorrhage secondary to a DACA aneurysm rupture. A right-handed patient presented with brutal onset of left temporal headache. Clinical examination revealed a Glasgow Coma Scale of 14 with a right crural hemiparesis. The cerebral CT scan showed a subarachnoid hemorrhage Fisher grade IV (Fig. 1a), with the majority of the blood in the pericallosal cistern. The angio-CT demonstrated a right A2 aneurysm at the pericallosal—callosomarginal junction; this was treated immediately by urgent endovascular coiling with no periprocedural complications. On day 1, the patient complained about the feeling of oppositional behavior from his non-dominant hand against his dominant hand. The left hand-dissociative movements were triggered by voluntary activities of his right hand: when we asked the patient to take an object with his right hand, his left hand seized the object before the right hand had time to reach it. The patient never doubted that the left hand was part of his own body, and he had no left/right hand confusion, but he felt that his left hand had its own will. No frontal release signs such as grasping or perseverance were observed. Neuropsychological testing showed language difficulties and clinical signs of callosal disconnection (bilateral taping disturbance, interdigital transfer difficulties, left tactile extinction) associated with executive dysfunction. In the subacute phase, T2and DWI-weightedMRI images showed involvement of the body and splenium of the corpus callosum with residual blood in the pericallosal cistern (Fig. 1b). The tractographic analysis confirmed the interhemispheric disconnection at the posterior third of the corpus callosum with a complete interruption of the commissural fibers (Fig. 1c, d). The patient underwent a specialized rehabilitation and had a good recovery with a complete return to autonomous daily life activities. DACA aneurysms account for about 3 to 7 % of intracranial aneurysms, most of which commonly arise at the bifurcation of the pericallosal and calloso-marginal arteries [3]. Ruptured DACA aneurysms are smaller than in other sites and are associated with more frequent intracerebral hematomas [4]. The Alien Hand Syndrome (AHS) was first described by Goldstein as a variety of clinical conditions whose common characteristic is the uncontrolled behavior or the feeling of strangeness of one extremity, most frequently involving the left hand [1, 2]. The common classification distinguishes between the posterior, or sensory form, of AHS and the anterior, or motor form, of this condition. To explain inconsistencies such as the phenomenon of diagonistic dyspraxia, Aboitiz (2003) proposed the distinction of five classes of AHS with peculiar clinical manifestations and specific anatomical substrates [1]. G. Cossu (*) :M. Messerer : R. T. Daniel Departement des Neurosciences Cliniques, Service de Neurochirurgie, Centre Hospitalier Universitaire Vaudois, Universite de Medecine et Biologie de Lausanne, Rue du Bugnon 44, 1011 Lausanne, Switzerland e-mail: giulia.cossu@chuv.ch