Role of incubitus truncal ataxia, and equivalent standing grade 3 ataxia in the diagnosis of central acute vestibular syndrome

•AVS requires a rapid and accurate evaluation to determine its etiology.•Truncal ataxia is shown as a sign that is easy to evaluate and very useful in the etiological diagnosis of AVS.•For those cases in which the patient cannot stand, assessing the incubitus truncal ataxiais a good substitute for truncal ataxia.