Recommended Reading – Volitional opsoclonus

Recommended Reading – Volitional opsoclonus


Volitional opsoclonus
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Patricio S. Espinosa, Joseph R. Berger. Neurology. 2005; 65 (5)

NEUROIMAGES


Opsoclonus (saccadomania) is defined as random, uncalled-for, large-amplitude, back-to-back saccades without intersaccadic intervals. An abnormality of the omnipause neurons in the brainstem nucleus raphe interpositus has been suggested, but not proven, as the etiology of opsoclonus.
1 Opsoclonus occurs with paraneoplastic, infectious, postinfectious, toxic, or metabolic disorders; however, it is often idiopathic. Intentional fixation instability may result in ocular movements closely resembling opsoclonus.2 We describe a patient with the volitional ability to replicate “opsoclonus.”


This 55-year-old man presented with transient left-sided numbness which, after thorough evaluation, was attributed to a transient ischemic episode. His neurologic examination, including ocular motility, was perfectly normal. However, he was voluntarily able to display wildly chaotic eye movements (video clip). He commented that he has been aware of this ability since childhood. No other family members, to the best of his knowledge, are able to replicate these eye movements. Analysis of the eye movements permitted by looping and pausing the video segment reveals that the actual eye movements are either diagonal (horizontal and vertical in phase) or, in some cases, elliptical (horizontal and vertical 90º out of phase), indicating that it is “voluntary opsoclonus,” also referred to as “voluntary multiplanar flutter” (Louis Dell’Osso, Cleveland, OH, personal communication, January 4, 2005).


The identification of volitional eye movements in clinical practice is important because it permits the distinction between neurologic and factitious disorders.

Video https://drive.google.com/open?id=1_mHS61kcc5YPUpPL_VeU5EYTVtaUoYE_

References:


1. Ridley A, Kennard C, Scholtz CL, Buttner-Ennever JA, Summers B, Turnbull A. Omnipause neurons in two cases of opsoclonus associated with oat cell carcinoma of the lung. Brain 1987;110(Pt 6):1699–1709.

2. Yee RD, Spiegel PH, Yamada T, Abel LA, Suzuki DA, Zee DS. Voluntary saccadic oscillations, resembling ocular flutter and opsoclonus. J Neuroophthalmol 1994;14:95–101.