Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli
Both auditory and vestibular primary afferent neurons can be activated by sound and vibration. This review relates the differences between them to the different receptor/synaptic mechanisms of the two systems, as shown by indicators of peripheral function—cochlear and vestibular compound action pote...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-11-01
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| Series: | Audiology Research |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2039-4349/13/6/79 |
| _version_ | 1797382028161712128 |
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| author | Christopher J. Pastras Ian S. Curthoys |
| author_facet | Christopher J. Pastras Ian S. Curthoys |
| author_sort | Christopher J. Pastras |
| collection | DOAJ |
| description | Both auditory and vestibular primary afferent neurons can be activated by sound and vibration. This review relates the differences between them to the different receptor/synaptic mechanisms of the two systems, as shown by indicators of peripheral function—cochlear and vestibular compound action potentials (cCAPs and vCAPs)—to click stimulation as recorded in animal studies. Sound- and vibration-sensitive type 1 receptors at the striola of the utricular macula are enveloped by the unique calyx afferent ending, which has three modes of synaptic transmission. Glutamate is the transmitter for both cochlear and vestibular primary afferents; however, blocking glutamate transmission has very little effect on vCAPs but greatly reduces cCAPs. We suggest that the ultrafast non-quantal synaptic mechanism called resistive coupling is the cause of the short latency vestibular afferent responses and related results—failure of transmitter blockade, masking, and temporal precision. This “ultrafast” non-quantal transmission is effectively electrical coupling that is dependent on the membrane potentials of the calyx and the type 1 receptor. The major clinical implication is that decreasing stimulus rise time increases vCAP response, corresponding to the increased VEMP response in human subjects. Short rise times are optimal in human clinical VEMP testing, whereas long rise times are mandatory for audiometric threshold testing. |
| first_indexed | 2024-03-08T21:00:28Z |
| format | Article |
| id | doaj.art-4a875f1bcf5d4803a3887cd1743474d2 |
| institution | Directory Open Access Journal |
| issn | 2039-4349 |
| language | English |
| last_indexed | 2024-03-08T21:00:28Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Audiology Research |
| spelling | doaj.art-4a875f1bcf5d4803a3887cd1743474d22023-12-22T13:53:05ZengMDPI AGAudiology Research2039-43492023-11-0113691092810.3390/audiolres13060079Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP StimuliChristopher J. Pastras0Ian S. Curthoys1Faculty of Science and Engineering, School of Engineering, Macquarie University, Sydney, NSW 2109, AustraliaVestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW 2006, AustraliaBoth auditory and vestibular primary afferent neurons can be activated by sound and vibration. This review relates the differences between them to the different receptor/synaptic mechanisms of the two systems, as shown by indicators of peripheral function—cochlear and vestibular compound action potentials (cCAPs and vCAPs)—to click stimulation as recorded in animal studies. Sound- and vibration-sensitive type 1 receptors at the striola of the utricular macula are enveloped by the unique calyx afferent ending, which has three modes of synaptic transmission. Glutamate is the transmitter for both cochlear and vestibular primary afferents; however, blocking glutamate transmission has very little effect on vCAPs but greatly reduces cCAPs. We suggest that the ultrafast non-quantal synaptic mechanism called resistive coupling is the cause of the short latency vestibular afferent responses and related results—failure of transmitter blockade, masking, and temporal precision. This “ultrafast” non-quantal transmission is effectively electrical coupling that is dependent on the membrane potentials of the calyx and the type 1 receptor. The major clinical implication is that decreasing stimulus rise time increases vCAP response, corresponding to the increased VEMP response in human subjects. Short rise times are optimal in human clinical VEMP testing, whereas long rise times are mandatory for audiometric threshold testing.https://www.mdpi.com/2039-4349/13/6/79VEMPotolithscompound action potentialCNQXnon-quantalresistive coupling |
| spellingShingle | Christopher J. Pastras Ian S. Curthoys Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli Audiology Research VEMP otoliths compound action potential CNQX non-quantal resistive coupling |
| title | Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli |
| title_full | Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli |
| title_fullStr | Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli |
| title_full_unstemmed | Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli |
| title_short | Vestibular Testing—New Physiological Results for the Optimization of Clinical VEMP Stimuli |
| title_sort | vestibular testing new physiological results for the optimization of clinical vemp stimuli |
| topic | VEMP otoliths compound action potential CNQX non-quantal resistive coupling |
| url | https://www.mdpi.com/2039-4349/13/6/79 |
| work_keys_str_mv | AT christopherjpastras vestibulartestingnewphysiologicalresultsfortheoptimizationofclinicalvempstimuli AT ianscurthoys vestibulartestingnewphysiologicalresultsfortheoptimizationofclinicalvempstimuli |