Acoustic Reflex Decay

The Acoustic Reflex Decay element simulates reflex decay testing. For each tested ear the learner presents a continuous tone at the reflex threshold + 10 dB, at 500 Hz and 1 kHz, watches whether the reflex holds for the whole tone or fades away, and calls the ear positive or negative for decay. In the designer it sits under More elements, in the Acoustic Reflexes group beside Acoustic Reflexes, listed as:

A sustained tone above the reflex threshold at 500 Hz and 1 kHz — call each ear positive or negative for decay

Like every Theta element, it follows the lifecycle Design → Settings → Testing → Scoring → Report.

The rule

The reflex rises to its first deflection and holds (2 s by default); decay is positive when it then falls by more than 50% of that first deflection before the tone ends (10 s as standard). Exactly 50% is negative — the criterion is greater than. One frequency is enough: an ear that holds at 500 Hz but decays at 1 kHz is positive.

Positive decay points to a retrocochlear (VIIIth nerve) problem, which is why the test is run. Only 500 Hz and 1 kHz are offered — even normal ears can show decay above 1 kHz, so a positive result there would mean nothing.

Design

Behind the scenes each ear's answer is stored against the stimulated ear — the ear whose nerve is being tested. What the cards, the console and the results call "Right" and "Left" follows the What Right / Left means setting (below): with the default probe-ear naming and a contralateral probe, the card named Right is the probe-right ear, so its tone is in the left ear. Each card's grey line spells out the route ("Stimulus left · probe right"). Remove an ear you don't want tested; at least one must stay (the lesson won't save with none).

Where the reflex thresholds come from

Reflex thresholds from picks the source:

An Acoustic Reflexes element in the lesson — the default when the lesson already has one when you add decay. Every attempt uses that element's thresholds for the same attempt, so if it is a template the two tests still agree. Contralateral decay stimulating the right ear reads the reflex recorded with the probe in the left ear, exactly as the reflex test stores it — under probe-ear naming, that's the card named Left. Where that element records no reflex, the frequency shows Absent: there is nothing to watch decay, so it is ignored, and an ear with no reflex at any tested frequency is not graded (the results screen's View data tab and the PDF say Could not test). Where it doesn't test that condition or frequency at all, the threshold entered here is used.
Enter the thresholds here — type each ear's thresholds into the table. They stay the same on every attempt.

Deleting the linked element switches the decay element back to its own thresholds.

Per ear

Result — Positive or Negative.
Per frequency, the reflex threshold (ART) and decay % — how much of the first deflection is lost by the time the tone stops. The table also shows the level the test should be run at (ART + the sensation level) and whether that frequency decays, is sustained, or has no reflex.

A preview under each ear draws the trace at the correct test level, with a dashed line where the trace would have to fall for a positive result.

Template vs fixed

Template — the Result is the category. Every attempt redraws the decay so it lands in it, kept well clear of the criterion so no case is a coin-flip. A positive ear decays at one or both frequencies (only ones with a reflex), so learners meet cases where only one frequency gives it away. The thresholds stay as entered — or vary with a linked template reflex element. Shuffle (under the Template badge) draws a new preview decay for each ear, keeping its result.
Fixed — the numbers are the case. Editing a threshold or decay % re-derives the Result, so the answer key always agrees with the trace the learner sees.

Quick-fill seeds both ears from a pattern: negative both ears (normal), right retrocochlear, left retrocochlear, or bilateral retrocochlear. The patterns are named by the pathology side — the ear being stimulated — so they read correctly under either naming: under probe-ear naming a right retrocochlear case shows its decay on the ear named Left.

Settings

Setting	Default	What it does
Probe placement	Contralateral	Where the probe records relative to the stimulated ear. Changes the labels and where the probe tone plays, not the result. Contralateral is the classic (Jerger) set-up; ipsilateral decay is also measured on modern equipment.
What Right / Left means	Linked reflex element's choice, else probe ear	Labels only, the same choice as Acoustic Reflexes: probe ear (the ear named is where the probe records) or stimulus ear (the ear named is the one tested). Linked to an Acoustic Reflexes element, decay follows that element's naming until you pick one here — Follow the linked Acoustic Reflexes element instead goes back. Not an Element Preset setting, so every new element starts by following. Each attempt keeps the naming it started with; attempts made before this setting existed keep their stimulus-ear names.
Tested frequencies	500 Hz, 1 kHz	Either or both — at least one.
Positive when decay exceeds	50%	The criterion. Changing it re-aligns the design (a fixed case's result follows its numbers; a template redraws inside its category).
Tone duration	10 s	How long the continuous tone plays.
Reflex holds for	2 s	How long the reflex stays at its first deflection before any decay starts — "got there, but couldn't sustain it". At least a second of decay is always left before the tone ends.
Test level above ART	10 dB	The sensation level the test should be run at.
Show the learner each ear's reflex threshold	On	Shows the learner each ear's ART in the console. Turn it off when the lesson has its own Acoustic Reflexes element and the learner should carry their thresholds across.
Lowest level / Highest level / Console opens at	60 / 115 / 80 dB HL	The level dial.

Everything here except the tested frequencies and the Right / Left naming is also an Element Preset setting, so an organization can set its own defaults for new decay elements.

Testing

The console has the Ear (named per the lesson's Right / Left setting), the frequency, the level dial and one Present button. Presenting plays a softer 226 Hz probe tone in the probe ear and the continuous stimulus in the stimulated ear, and draws the trace in real time over the tone; Stop tone ends it early. Ten dB or more below the reflex threshold there is nothing to watch; just below it the reflex is partial, at threshold it is small, and at ART + 10 dB it is clear. The reflex threshold (when the lesson shows it) sits at the right of the header above the plot, and reads absent where a linked reflex element records none. Pointing at (or dragging a finger across) the trace reads the deflection at that moment.

The call — Positive or Negative — is made per ear.

In practice mode a 50% decay line can be drawn on the trace and an answer key revealed; neither is offered in exam mode. The gear menu also switches off sound and the real-time sweep, turns on the results summary (off to start), and lists the keyboard shortcuts (↑/↓ level, ←/→ frequency, Space present or stop, E switch ear). These view choices are remembered in that browser across elements and sittings — except the answer key, which starts off on every element so a peek while practicing can never carry into an exam.

Every run is recorded with its ear, frequency and level — and the values that drew the trace, so Attempt Replay redraws exactly what the learner saw — along with every early stop and every call.

Scoring

Tri-state per field, per ear — Scored, Report-only, or Off, with Sync Ears.

Field	Default	What's compared
Decay result	Scored	The learner's positive / negative call vs the call derived from the design's numbers.
Stimulus level (per frequency)	Off	The level of the learner's last run at that frequency vs ART + the sensation level, within a tolerance of exact, ±5 or ±10 dB. A frequency never run is wrong.

An unanswered call counts as wrong.

Report

The results screen carries a breakdown (every scored and report-only field, expected vs submitted) and a View data tab. The PDF gives each ear a block: the decay at the correct level (dashed grey) beside the learner's last run level (ear colour) at each frequency, a table of ART, test level, the level the learner ran and the decay %, and the expected call against theirs — followed by the scoring table. An ear switched off on the Scoring & Report tab is left out of both.

Explore

Acoustic Reflex Decay has its own card in the Element Explorer: the designer and the test settings on one page, to try patterns, thresholds and how long the reflex holds, then run it in the simulator or save it as a lesson (Pro to save, like the other reflex and OAE explorers).

Advanced Analytics

Metric	What it measures
Reflex decay call	Whether each tested ear was called correctly. The ear filter uses the lesson's own Right / Left naming, as the results screen does.
Decay test level (ART + sensation level)	How many frequencies were last run at the right level, within the tolerance — a report can widen the tolerance. Needs the level field scored or report-only.
Ran the decay test before calling it	Whether each call came after a run on that ear, from the action trail.