Promontorial test

The promontorial test is a method for examining the transmission of stimuli from the inner ear via the auditory nerve to the brain stem .

execution

An electrically conductive needle is pushed through the eardrum and placed on the promontory of the tympani . Measuring electrodes are placed on the mastoid and usually two other points on the head . Voltage pulses of a defined amplitude and shape are then introduced via the needle electrode . These are picked up and passed on by the auditory nerve. The measuring electrodes then record different potentials, which are created with a time delay as a result of the transmission to the pulse.

A subjective description of the simulated sound sensations by the patient is also possible and is very valuable for assessing the transmission of stimuli.

application

The promontorial test allows a statement to be made about the condition of the auditory nerve and the subsequent stimulus transmission, even if the inner ear is irreparably damaged. This may be helpful before a cochlear implant is inserted, as a cochlear implant requires an intact auditory nerve.

Risks

It is an invasive examination method in which the patient's eardrum must be injured. This creates a risk of infection and the possibility that the middle ear may be affected when the needle is inserted . The facial nerve runs in the immediate vicinity of the eardrum ; many patients experience irritation to severe pain, which can cause some to faint .

Alternative methods

Instead of introducing the electrical signals at the promontory tympani, electrical stimulation of the ear canal can be carried out. The wall of the ear canal is contacted with an electrode. This avoids hearing damage.

Individual evidence

↑ Paul R. Kileny, Teresa A. Zwolan, Susan Zimmerman-Phillips, Steven A. Telian: Electrically Evoked Auditory Brain Stem Response in Pediatric Patients With cochlear implants . In: Archives of Otolaryngology - Head & Neck Surgery . tape 120 , 1994, ISSN 0886-4470 , pp. 1083-1090 , doi : 10.1001 / archotol.1994.01880340029006 , PMID 7917191 .
↑ K. Neumann, P. Raab, C. Preibisch, H. Lanfermann, I. Reimold and J. Kiefer: Activation of the auditory cortex by means of electrical stimulation of the ear canal in deaf adults - an fMRI study . 2002 ( PDF ).

[1] Paul R. Kileny, Teresa A. Zwolan, Susan Zimmerman-Phillips, Steven A. Telian: Electrically Evoked Auditory Brain Stem Response in Pediatric Patients With cochlear implants . In: Archives of Otolaryngology - Head & Neck Surgery . tape 120 , 1994, ISSN 0886-4470 , pp. 1083-1090 , doi : 10.1001 / archotol.1994.01880340029006 , PMID 7917191 .

[DGA_2002-2] K. Neumann, P. Raab, C. Preibisch, H. Lanfermann, I. Reimold and J. Kiefer: Activation of the auditory cortex by means of electrical stimulation of the ear canal in deaf adults - an fMRI study . 2002 ( PDF ).