The Neural Basis of Skull Vibration Induced Nystagmus (SVIN)

Round 1

Reviewer 1 Report

In this work the author addresses and clarifies some aspects of the vibratory test. Very interesting is the principle of neural imbalance which is applied in the systematic description of vestibular receptors. The mention of the canal block is also very interesting, which could be a starting point for future research for the diagnostic evaluation of Canal Jam.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

I have read with great interest the manuscript entitled “The Neural Basis of Skull Vibration Induced Nystagmus”

This article provides physiological arguments for a better understanding and interpretation of SVINT, a recent test using bone conducted vibrations ( BCV)  in light of results obtained in afferent neurons of the primary canal and otolith in response to low frequency vibratory stimulation of the skull and what is currently known about unilateral selective stimulation of nerves eliciting eye movements (work of Cohen and colleagues).

The concept of imbalance principle between the two vestibular nuclei (VN) is presented and explained to give practitioners a better understanding of the different findings usually seen in clinical practice. The author details the situation in TUVL, uSCD, Meniere's disease and gives the interpretation of a recent clinical situation in unilateral Horizontal SCC occlusion.

The simplicity and clarity of this physiological update provide great practical value to the clinical user.

Minor remarks

In the legend to Figure 1, it is stated that “the horizontal (and torsional) quick phases are directed away from the lesioned ear”. However, if one considers the common ordinate scale of the figure, the horizontal and torsional quick phases appear to be in opposite directions.

The meaning of the letters RM seen in the figure 1 needs to be clarified.

In the legend to Figure 2, the author Kluwer is not associated with reference no. 2

Lines 154-155: it is written “(represented by 3 lines near left labyrinth in D-H)” whereas the 3 lines are near the right labyrinth in figure 3.

Typing error line 220: ”...SPV pf both components...”  should be “... SPV of both components”

Typing error: Legend figure 4, line 234:”(from Cohen Suzuki, Bender 1964)” the “,” between “Cohen” and Suzuki is missing”. It should read: ”(from Cohen, Suzuki, Bender 1964)”

Remarks

The potential contribution of otolith structures to the constitution of nystagmus after BCV would be interesting to comment further considering the developed links of the Utricle with the oculomotor CN.

In SCD,  do all SCCs become more sensitive to high frequencies or only the dehiscent anterior SCC? How to explain the horizontal component of the SVIN observed at very high frequencies such as 500Hz?

This presentation is useful for a better understanding by practitioners of the test.  The results and their interpretation based on  the “ imbalance principle“ in the Vestibular Nuclei is very interesting especially in the light of the contribution of the SCC. However, this article provides limited insight into the possible role of otolith structures in the constitution of the SVIN.

Author Response

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Author Response File: Author Response.docx