The undulating toe flexion sign in brain death.
Brain-dead patients may exhibit gross spontaneous and reflex movements (e.g., Babinski sign, stereotypic flexion of one or more limbs, and Lazarus sign). We report three brain-dead patients who had unusual complex sequential movements of the toes. Undulating toe flexion was elicited by noxious stimuli to the lower extremities, and consisted of initial plantar flexion of the great toe, followed by sequential brief plantar flexion of the second, third, fourth, and fifth toes. The undulating toe flexion sign differs from previously described responses characterized by plantar flexion of the toes (e.g., Rosselimo's sign and the Mendel-Bechterew sign) in that it consists of complex patterned sequential movements of the digits rather than brief simultaneous flexion and/or fanning of the toes. Neurologists should be aware of this unusual finding, which should not preclude the diagnosis of brain death.