The four otoacoustic emission types are distinguished by whether and how they are evoked

Evidence

There are four kinds of otoacoustic emissions. The spontaneous otoacoustic emissions (SOAEs) are produced, as mentioned above, without any sound stimulus. The simultaneously evoked otoacoustic emissions (SEOAEs) can be measured in the closed ear canal during continuous tonal stimulation of the ear. Delayed evoked otoacoustic emissions (DEOAEs) are responses to short periodic sound impulses: these sounds may be either broad-band clicks or narrow-band tone bursts with Gaussian-shaped envelopes. After a delay which depends on the frequency of the evoking tone burst, otoacoustic emissions are measured as a response to the stimuli. Because the DEOAEs are triggered by the evoking sequence of sound bursts, the technique of timesynchronous averaging can be used to enhance the very small signal-to-noise ratio of these emissions. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 246

Categorization

• DEFINE: Enumerates and defines the four kinds of otoacoustic emissions: SOAEs, SEOAEs, DEOAEs, and DPOAEs.
• corroborated: 3 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 246
• XREF: connects to: Spontaneous and evoked otoacoustic emissions likely share a single source — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 309; Otoacoustic emissions originate peripherally before neural encoding begins

Broader Connections

• Spontaneous and evoked otoacoustic emissions likely share a single source #complicates (0.80) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 309
• Otoacoustic emissions originate peripherally before neural encoding begins #complicates (0.72)