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Published on: March 1, 2015
Nucleus prepositus hypoglossi lesions produce a unique ocular motor syndrome
Sung-Hee Kim1, David S Zee1, Sascha du Lac1
1From the Department of Neurology (S.-H.K.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Neurology, Ophthalmology, Otolaryngology-Head and Neck Surgery, and Neuroscience (D.S.Z., S.d.L.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Biomedical Laboratory Science (H.J.K.), Kyungdong University, Goseong-Gun, Gangwon-do; and Department of Neurology (J.-S.K.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, Korea.
Objective:
To describe the ocular motor abnormalities in 9 patients with a lesion involving the nucleus prepositus hypoglossi (NPH), a key constituent of a vestibular-cerebellar-brainstem neural network that ensures that the eyes are held steady in all positions of gaze.
Methods:
We recorded eye movements, including the vestibulo-ocular reflex during head impulses, in patients with vertigo and a lesion involving the NPH.
Results:
Our patients showed an ipsilesional-beating spontaneous nystagmus, horizontal gaze-evoked nystagmus more intense on looking toward the ipsilesional side, impaired pursuit more to the ipsilesional side, central patterns of head-shaking nystagmus, contralateral eye deviation, and decreased vestibulo-ocular reflex gain during contralesionally directed head impulses.
Conclusions:
We attribute these findings to an imbalance in the NPH-inferior olive-flocculus-vestibular nucleus loop, and the ocular motor abnormalities provide a new brainstem localization for patients with acute vertigo.
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