Inferior Vestibular Nerve

Tom Boismier, MPH teb at mailgw-vtc.oto.med.umich.edu
Thu Apr 13 13:32:48 EST 1995


In article <199504121533.LAA02686 at orichalc.acsu.buffalo.edu> xyz at ACSU.BUFFALO.EDU (Xiangyang Zheng) writes:

>Could anybody in this group know that if the Vestibular Nystagmus necessarily 
>develops when one of  the vestibular nerves---the Inferior Vestibular Nerve 
>is sectioned? Please drop me a message in detail if possible.

Any event that causes a change in the tonic firing rate (either increase 
or decrease from one end organ) entering the vestibular nuclei can produce 
nystagmus and vertigo. The central nervous system will quickly act to suppress 
the nystagmus by"clamping" the output of the vestibular nuclei, usually within 
hours, then over time will recalibrate the nuclei in order to compensate for 
the change. 

Central compensation typically occurs within 2 to 3 days in the cat, and 
can take 1 to 6 weeks in an otherwise healthy human. existsing CNS disease, 
CNS suppressant medications, and inactivity can delay or stop compensation.
Head movements excercises (as are done in Vestibular Rehabilitation physical 
therapy programs) can speed up the process. 

The surgical procedure "vestibular nerve section" is performed frequently in 
intractable Meniere's disease. The theory is that the CNS cannot compensate 
for a damaged ear who's tonic firing rate is constantly changing. The nerve 
section gives the CNS a stable lesion from which compensation can proceed.



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