Module 5

Tools

Interactive simulators and figures for exploring how an ASSR recording behaves.

ASSR simulator

This simulator generates a four-carrier ASSR recording (500, 1000, 2000, 4000 Hz). Set each carrier's true behavioural threshold with the sliders, and watch how the recorded response and the estimated ASSR threshold respond.

Two views share the same underlying model. The amplitude-vs-intensity view shows how response amplitude grows once the stimulus rises above threshold — a filled marker means the response was statistically detected, a hollow one means it was not. The polar / vector view shows the same responses as vectors: length is amplitude, angle is phase, and any vector inside the shaded ring is buried in noise.

01020304050Response amplitude (nV)01020304050607080Stimulus intensity (dB HL)
500 Hz est. threshold: 30 dB HL1000 Hz est. threshold: 20 dB HL2000 Hz est. threshold: 30 dB HL4000 Hz est. threshold: 40 dB HL
Teaching model — illustrative values, not calibrated clinical data. Drag a slider to set an ear's true behavioural threshold; the recording and estimated threshold update live.

Audiogram & the ASSR correction

The audiogram below plots hearing level against frequency in the standard way — O for the right ear, X for the left, dB HL increasing downward. Here it is used to show the conversion from Module 4: the X trace is the recorded ASSR threshold, and the O trace is the estimated behavioural audiogram after a per-carrier correction is applied. Notice the recorded ASSR trace always sits below (poorer than) the corrected estimate.

-10020406080100120500 Hz1k Hz2k Hz4k HzHearing level (dB HL)
O Right earX Left ear
O = estimated behavioural audiogram (after correction). X = recorded ASSR thresholds, before correction — consistently poorer than the corrected estimate.
Corrected pure-tone average: 32.5 dB HL — Mild range. Per-carrier corrected estimate: 500 Hz 30 dB, 1k Hz 30 dB, 2k Hz 35 dB, 4k Hz 35 dB.

Correction values here are illustrative teaching figures in the range reported for infants; real correction is device- and population-specific.

Threshold search animation

This animation steps a single carrier's stimulus intensity downward, the way an instrument seeks a threshold. Watch the response shrink toward the noise floor until it can no longer be detected — the lowest intensity with a present response is the ASSR threshold. Use play, or step through it manually.

80 dB HL2000 Hz carrierResponse 36.9 nV · SNR 10.5 dB✓ Response present
Step 1 / 9
Stepping intensity downward: the response shrinks until it can no longer be told from noise. The lowest intensity with a present response is the ASSR threshold. Motion is reduced — use Step to advance manually.