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BRIEF COMMUNICATIONS: Michael von Brevern, Andrew H. Clarke, and Thomas Lempert Continuous vertigo and spontaneous nystagmus due to canalolithiasis of the horizontal canal Neurology 2001; 56: 684-686 [Abstract] [Full text] [PDF]

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Reply from the authors

Michael von Brevern, "Andrew H Clarke, Thomas Lempert"   (10 April 2001)

Nystagmus with canalith jam

R John Leigh   (10 April 2001)

Reply from the authors 10 April 2001
Michael von Brevern , "Andrew H Clarke, Thomas Lempert" Send Correspondence to journal: Re: Reply from the authors michael.von_brevern{at}charite.de Michael von Brevern, et al.	We thank Dr. Leigh for his comment on our case report. Dr. Leigh and colleagues have found that vertical eye drift can be a physiological phenomenon that depends on head position and is thus influenced by otolithic input(1). We would like to draw attention to another recent study (2) which demonstrated the occurence of positional vertical nystagmus in a large group of normal subjects with slow phase velocities even exceeding 5°/s in some subjects. However, one has to bear in mind that eye movement recordings in these studies and in our report were performed in darkness which completely inhibits fixation suppression. Therefore, in clinical practice, pure vertical positional nystagmus observed with or without Frenzel glasses should still raise the suspicion of a central vestibular lesion. 1. Kim JI, Somers JT, Stahl JS, Bhidayasiri R, Leigh RJ. Vertical nystagmus: Effects of head position, scopolamine, and nicotine. Neurology 2000; 54 (Suppl3): A169-170 (Abstract). 2. Bisdorff AR, Sancovic S, Debatisse D, Bentley C, Gresty MA, Bronstein MA. Positional nystagmus in the dark in normal subjects. Neuro- ophthalmology 2000; 24, 283-290.
Nystagmus with canalith jam 10 April 2001
R John Leigh, Neurology Case Western Reserve University Send Correspondence to journal: Re: Nystagmus with canalith jam rjl4{at}po.cwru.edu R John Leigh	I congratulate Drs. von Brevern, Clarke and Lempert for an excellent example of interpretation of clinical signs, in this fascinating case, using current knowledge of vestibular physiology and anatomy. The clarity of their account make this a superb teaching case. With respect to the direction of their patient's nystagmus, described in the final paragraph of their report, the vertical component might be because: (1) the lateral canals show substantial variation in their position from subject to subject (see variance of data in the classic study by Blanks and colleagues) so that stimulation of them may be expected to produce vertical eye movements; (2) "physiological vertical eye drift" in darkness in normal subjects may be otolithic in origin. We have recorded drifts of the eyes (search coil) in darkness in four subjects first with their head erect and then head inverted for several minutes. Three subjects showed low-amplitude brow-beating nystagmus with their head erect while all four showed chin-beating nystagmus with their heads inverted (Kim et al, 2000; 2001). These findings suggest a normal, physiological change in otolithic inputs brought about by the static head orientation Blanks RHI, Curthoys IS, Markham CH. Planar relationships of the semicircular canals in man. Acta Otolaryngol 1975;80:185-196. Kim JI, Somers JT, Stahl JS, Bhidayasiri R, Leigh RJ. Vertical Nystagmus: Effects of Head Position, Scopolamine, and Nicotine. Neurology 2000; 54 (Suppl3): A169-70 (Abstract). Kim JI, Somers JT, Stahl JS, Bhidayasiri R, Leigh RJ. Vertical nystagmus in normal subjects: effects of head position, nicotine and scopolamine. J Vestibular Res (2001, in press).