Rare valiant vertical one-and-a-half syndrome without ipsilateral upward gaze palsy in a patient with thalamomesencephalic stroke.

Bilateral upward and ipsilateral downward gaze palsy due to a unilateral thalamomesencephalic stroke is called vertical one-and-a-half syndrome (VOHS). Here, we report a valiant VOHS case who presented contralateral upward and ipsilateral downward gaze palsy due to a unilateral thalamomesencephalic stroke. The neuronal fiber connections associated with vertical gaze are not completely understood, so the present case provides an important proof to obtain a better understanding of vertical gaze mechanisms.