[Electrodiagnostic support in an atypical form of amyotrophic lateral sclerosis (Vulpian-Bernhardt syndrome)].

Background: Vulpian-Bernhardt syndrome is an atypical form of the motor neuron disease described since the 19th century. The importance of a timely diagnosis lies in the increased survival present in this variant. Due to the clinical rarity and complex diagnosis we report a clinical case of this disease, which is why we describe the typical clinical presentation, the diagnostic approach, and we make a bibliographic review of this neurodegenerative disorder as well. Clinical case: Latin American man whose clinical case onset was characterized by thoracic asymmetric and increasing limb weakness, showing affection from distal to proximal upper limbs area. Subsequently, symptoms worsened to the point of limiting day-to-day activities and conditioning patient's physical independence. Physical examination was consistent with motor neuron disease. Nerve conduction studies were performed and confirmed findings compatible with motor neuron involvement limited to thoracic limbs. Conclusion: Vulpian-Bernhardt syndrome is an uncommon form of motor neuron disease. Due to the rarity of its presentation, it is frequent to confuse clinical profile even for trained physicians. The importance of electrodiagnosis relies in identifying the neurogenic origin of the disease, as well as the active denervation and reinnervation data. Considering that with this syndrome patients have a longer survival than with the classic form of amyotrophic lateral sclerosis, it is important to have a clear diagnosis approach in order to provide a better quality of life and supportive treatment.