General Principles Part 1 Historical And Classifications
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This document provides an overview of auditory evoked responses and their classification. It discusses the historical development of different auditory evoked potentials and how they can be classified based on whether they are evoked or non-evoked, the time period following stimulation, the location of recording electrodes, and the structures in the auditory system that generate them. Key auditory evoked responses discussed include the cochlear microphonic, summating potential, auditory brainstem response, middle latency response, and P300.
![Electrical potentials in the human nervous system can be recorded both in response to specific external stimuli (event-related potentials [ERP] ) and in an ongoing manner without the presence of external stimuli (non-evoked or non-event related). Evoked Versus Non-Evoked Responses Henry P. Trahan, Au.D.](https://image.slidesharecdn.com/General_Principles_Part_1_Historical_and_Classifications-090220095551-phpapp01/85/General-Principles-Part-1-Historical-And-Classifications-6-320.jpg)
General Principles Part 1 Historical And Classifications
- 1. AUD 744 Overview of Auditory Evoked Responses Transitional Audiology Program AUD 616 Auditory Evoked Responses Residential Audiology Program Henry P. Trahan, Au.D.
- 2. Part 1 Auditory Evoked Responses Historical Overview And General Principles
- 3. 1929 – Human EEG -- Berger 1930 – First paper on AEPs in general -- Weaver and Bray 1930 – Earliest of AEPs discovered – Cochlear Microphonic – Weaver and Bray 1939 – First recorded alteration in EEG with auditory stim. in humans – P. Davis 1941 – CM recorded from round window in human through TM perforation – Pearlman and Case Historical Time Line Henry P. Trahan, Au.D.
- 4. 1950 – Summating Potential in animal recorded – Davis 1958 – Description of average response computer (ARC) – Clark 1967 – AP with earlobe electrodes. ABR response first shown but reported as ECochG – Sohmer and Feinmesser 1971 – AP recorded in human w/external ear canal electrode – Saloman & Elberling Historical Time Line Henry P. Trahan, Au.D.
- 5. 1971 – ABR first described in animals - Jewett 1971 – ABR response first described in humans – Jewett, Romano, Williston 1974 – CM, SP, and AP record in human w/ ear canal electrode -- Coats 1974 – Relationship between ECochG abnormalities and Meniere’s disease – Eggermont 1974 – Description of ABR in infants & young children – Hecox and Galambos Historical Time Line Henry P. Trahan, Au.D.
- 6. Electrical potentials in the human nervous system can be recorded both in response to specific external stimuli (event-related potentials [ERP] ) and in an ongoing manner without the presence of external stimuli (non-evoked or non-event related). Evoked Versus Non-Evoked Responses Henry P. Trahan, Au.D.
- 7. Non-Event Related Event Related EEG ECochG ABR Evoked Versus Non-Evoked Responses Henry P. Trahan, Au.D.
- 8. Auditory Evoked Responses (AERs) represent electrical responses of the Auditory nervous system to externally presented acoustic stimuli. Auditory Evoked Responses Henry P. Trahan, Au.D.
- 9. AEPs can be classified according to whether their characteristics are determined by external or internal processes ( exogenous vs. endogenous ) AEPs can be classified according to the time epoch following the stimulus in which they occur. ( latency ) AEPs can be classified according to the relation of the recording electrodes to the actual generator sites. ( Near Field vs. Far Field ) AEPs can be classified according to what structures in the auditory system generates them . Classification of Auditory Evoked Responses Henry P. Trahan, Au.D.
- 10. Classification of Auditory Evoked Responses Henry P. Trahan, Au.D. AEPs can be classified according to whether their characteristics are determined by external or internal processes. Exogenous Endogenous
- 11. Classification of AEPs AEPs can be classified according to the time epoch following the stimulus in which they occur. Very Early (0 – 1.5 msec) (First) (CM, SP, N1) (ECochG) Early (1.5 -12 msec) (Fast) Nerve and brainstem) (ABR) Middle (12 - 50 msec) (thalamus and aud. cortex) (MLR) Slow (50 – 300 msec) (1 o and 2 o areas of cortex) (ALR) P300 (300+ msec) ( 1 o and association areas) (P300)
- 12. The Family of AEPs
- 13. The Family of AEPs vertex positive I II III IV V VI N o P o N a P a N b P1 N 1 P2 N2 P300
- 15. Classification of AEPs AEPs can be classified according to the relation of the recording electrodes to the actual generator sites. Far-Field Response (Electrodes some distance away) Near-Field Response (Electrodes in close proximity)
- 16. Clinically, AEPs are almost always recorded at far-field., with electrodes located outside of the skull (extracranially), usually at the scalp. Two exceptions are: During intraoperative monitoring (when recording electrodes mat be placed directly on the VIIIth Nerve) and During transtympanic membrane ECochG, (when a recording electrode may be placed on the promontory).
- 17. AEPs can be classified according to what structures in the auditory system generates them. Receptor Potentials (cochlear hair cells) Neurogenic Potentials (VIIIth N &/or brain stem) Classification of AEPs