Reader response: Teaching Video NeuroImages: Palsy of conjugate horizontal gaze and face due to isolated abducens nuclear infarction

I read and viewed with interest the Teaching Video NeuroImage by Kim et al.1 Clearly, the reported patient did not have an “isolated” abducens nuclear infarction, as that would have caused a truly isolated ipsilateral horizontal gaze palsy. The ipsilateral facial palsy was caused by damage to the facial nerve fascicles adjacent to the abducens nucleus. Although the authors indicate this in the body of the text,1 the title of the article suggests that both the horizontal gaze palsy and the facial palsy were caused by the abducens nuclear infarction. I would hate for those who simply read the title of the otherwise excellent vignette to think that facial nerve fibers are somehow located within the abducens nerve nucleus. It is confusing enough for physicians to remember that the nucleus contains both axons destined for the ipsilateral lateral rectus and axons of the medial longitudinal fasciculus destined for the contralateral medial rectus so that abducens nuclear lesions cause an ipsilateral horizontal gaze palsy rather than a sixth nerve palsy.