Focal motor seizure Focal bilateral motor seizure 2020-03-15T07:21:57Z A type of focal motor seizure (it commences in one hemisphere) involving bilateral muscle groups rapidly at seizure onset. Not to be confused with a focal to bilateral tonic-clonic seizure (to which it may progress). Certain frontal lobe seizure sub-types have bilateral motor features at onset, often with asymmetric posturing. Typically, there is extension of the upper limb (at the elbow) contralateral to the hemisphere of seizure onset (often with a clenched fist and flexion at the wrist) and flexion of the ipsilateral upper limb at the elbow. This type of seizure is also described as a 'fencer's posture' or a 'figure of 4'.