Table 2

Results of listening tests

TestLower age limit for test (months)Score expected by chanceScoreMann–Whitney test comparing unilateral with bilateralMann–Whitney test comparing bilateral with normally-hearing
UnilateralBilateralNormally hearingzp Valuezp Value
Left–right discrimination ±60° (percentage correct)185065.0 (45.0 to 80.0) 19/20100.0 (87.5 to 100.0) 30/30100.0 (100.0 to 100.0) 56/56−4.100.00−1.720.08
Left–right discrimination ±30° (percentage correct)185055.0 (39.2 to 70.0) 17/2085.0 (65.0 to 96.3) 30/30100.0 (90.9 to 100.0) 55/56−3.310.00−3.830.00
Localisation (percentage correct)4833.342.5 (33.3 to 56.7) 14/1671.7 (50.4 to 96.6) 20/22Not measured−2.930.00
Movement tracking (percentage correct)182525.0 (0.0 to 25.0) 20/2050.0 (25.0 to 100.0) 30/30100.0 (100.0 to 100.0) 55/56−3.470.00−5.190.00
Spatial release from masking, noise ipsilateral to first implant (dB)36NA−0.48 (−5.19 to +2.31) 16/19+4.75 (+0.37 to +5.26) 25/27+5.19 (+2.69 to +7.19) 40/40*−2.920.00−2.290.02
Spatial release from masking, noise contralateral to first implant (dB)36NA+6.25 (+4.75 to +9.25) 15/19+4.26 (+2.75 to +7.78) 24/27+5.19 (+2.69 to +7.19) 40/40*−1.420.16−0.310.77
  • In the ‘Score’ columns, cells contain median scores, 25th and 75th percentiles (in parentheses), and the number of children contributing data relative to the number of children above the age limit for that test (in italics). Higher scores indicate better performance. The standardised Mann–Whitney statistic, z, is listed alongside the associated p value. Using a Bonferroni correction for multiple comparisons, a difference is statistically signifi cant if p<0.025.

  • * Mean of SRM with noise left (median 6.27 dB) and noise right (median 4.74 dB). These two measures did not differ signifi cantly (Wilcoxon signed-rank test, p>0.05).