Influence of target size on vertical gaze palsy in a pathologically proven case of progressive supranuclear palsy

Authors

  • Barry M. Seemungal MD,

    1. The Academic Department of Neuro-Otology, Division of Neurosciences and Psychological Medicine, Imperial College Faculty of Medicine, Charing Cross Hospital, London, United Kingdom
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  • Mary Faldon MD,

    1. The Academic Department of Neuro-Otology, Division of Neurosciences and Psychological Medicine, Imperial College Faculty of Medicine, Charing Cross Hospital, London, United Kingdom
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  • Tamas Revesz MD,

    1. Institute of Neurology, London, United Kingdom
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  • Andrew J. Lees MD,

    1. Institute of Neurology, London, United Kingdom
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  • David S. Zee MD,

    1. The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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  • Adolfo M. Bronstein MD

    Corresponding author
    1. The Academic Department of Neuro-Otology, Division of Neurosciences and Psychological Medicine, Imperial College Faculty of Medicine, Charing Cross Hospital, London, United Kingdom
    • The Academic Department of Neuro-Otology, Division of Neurosciences and Psychological Medicine, Imperial College School Of Medicine, Charing Cross Hospital Campus, St. Dunstan's Road, London W6 8RF, United Kindgom
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  • A videotape accompanies this article.

Abstract

We document a new oculomotor phenomenon in a patient with pathologically proven progressive supranuclear gaze palsy (PSP), namely that vertical gaze excursion improves with larger pursuit targets. We used computerised video-oculography during vertical smooth pursuit eye movements (SPEM) of circular targets of diameter 0.16 degrees and 16 degrees, sinusoidally oscillating at 0.08 Hz (peak-to-peak amplitude 49 degrees). Increasing target size improved vertical gaze excursion from 10 degrees to 25 degrees. There was no concomitant increase in slow phase eye velocity. The findings could be explained by a potentiation of the position control mechanism of pursuit by target size due to increased activation of brainstem pursuit-optokinetic pathways and to higher order attentional mechanisms. This observation may be useful in the clinical assessment of PSP patients with severe neck rigidity in whom the doll's head–eye manoeuvre cannot be performed by comparing the degree of vertical gaze palsy during smooth pursuit testing between at least two differently sized targets and observing whether there is a larger excursion in response to a large target such as a newspaper. © 2003 Movement Disorder Society

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