Stridor

Stridor is a Teachable Perk unique to The Nurse . It can be unlocked for all other Characters from Level 30 onwards:

Descriptions may vary from their in-game version for reasons explained here.
Mobile View displays the values in small print after the modifier words.

Icon	Cost
	2,000	5,000	4,000
			5,000
			6,000
Description
You are acutely sensitive to the breathing of your prey. * '''Increases''' the volume of Survivors' ''Grunts of Pain'' by '''<span class="luaClr clr clr2" style="color: #e8c252;">25</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">50</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">50</span> %'''. * '''Increases''' the volume of Survivors' regular breathing by '''<span class="luaClr clr clr2" style="color: #e8c252;">0</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">0</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">25</span> %'''. You are acutely sensitive to the breathing of your prey. Increases the volume of Survivors' Grunts of Pain by 25/50/50 %. Increases the volume of Survivors' regular breathing by 0/0/25 %. "If you do not stop and catch your breath... she will."

Icon	Description
	Unlocking this Perk makes it available in the Bloodweb of all Survivors You are acutely sensitive to the breathing of your prey. * '''Increases''' the volume of Survivors' ''Grunts of Pain'' by <span class="luaClr clr clr13" style="color: #418284;">'''Several Percent'''</span>. * '''Increases''' the volume of Survivors' regular breathing by <span class="luaClr clr clr13" style="color: #418284;">'''Several Percent'''</span>. You are acutely sensitive to the breathing of your prey. Increases the volume of Survivors' Grunts of Pain by Several Percent. Increases the volume of Survivors' regular breathing by Several Percent. "If you do not stop and catch your breath... she will." May be unlocked in the Shrine of Secrets or in Nurse's Bloodweb at Level 30

Change Log

Patch 5.1.0

Nerf: Grunts of Pain and Breathing are now multiplicative values. This makes Stridor useless against Iron Will and Off the Record.

Old Breathing Volumes

Note: the following information no longer applies as of Patch 5.1.0

The percentages on both Stridor and its Survivor-pendant Iron Will were misleading in their interaction with one another, as contrary to the popular perception of percentages, they did not represent actual percentages in the Game code, but rather numeric values that were combined additively.
This was ultimately changed with Patch 5.1.0.

A good analogy was a volume slider ranging from 0 to 100, which could also go above 100 if necessary.

Positive values moved the volume slider upwards, increasing the volume.
Negative values moved the volume slider downwards, lowering the volume.

Grunts of Pain

Volume Levels
	No Stridor	Stridor I (+25)	Stridor II & III (+50)
No Iron Will	100	125	150
Iron Will I (-50)	50	75	100
Iron Will II (-75)	25	50	75
Iron Will III (-100)	0	25	50

Regular Breathing

Volume Levels
Stridor I (+0)	Stridor II (+0)	Stridor III (+25)
100	100	125

Trivia

The term "Stridor" describes a high-pitched wheezing sound caused by disrupted airflow, which is also what The Nurse suffers from.

Gallery

Interaction between Iron Will III and Stridor III up to Patch 5.1.0