. 2022 Feb 22;43(2):255–267. doi: 10.1097/AUD.0000000000001204

TABLE 2.

Calculating Spatial Speech Recognition Scores using SNR-50 outcomes (paraphrased from Gartrell et al. 2014)

Spatial Measure	Calculation Listing Modality (Target/Masker)
Binaural summation	NH (S₀N₀) – CI/HA + NH (S₀N₀)
Head shadow	NH (S₀N_Contra) – CI/HA + NH (S₀N_Contra)
Binaural squelch	NH (S₀N_Ci) – CI/HA + NH (S₀N_Ci)
SRM (N_Ci)	CI/HA + NH (S₀N₀) – CI/HA + NH (S₀N_Ci)
SRM (N_Contra)	CI/HA + NH (S₀N₀) – CI/HA + NH (S₀N_Contra)

NH = listening with normal-hearing ear alone (device removed).

CI/HA + NH = listening with CI/HA or HA and normal-hearing ear together (device on).

S₀ = speech signal located at 0° azimuth.

N₀ = Noise/masking signal located at 0° azimuth.

N_Contra = Noise/masking signal directed toward the normal-hearing ear.

N_Ci = Noise/masking signal directed toward the deaf ear; SRM = spatial release from masking.