Dose-Dependent Pattern of Cochlear Synaptic Degeneration in C57BL/6J Mice Induced by Repeated Noise Exposure

Table 1

ABR threshold shifts at 1 day and 14 days after repeated noise exposure at various intensities.

Intensity (dB SPL)	ABR threshold shifts (dB HL)
	4 kHz		8 kHz		11.3 kHz		16 kHz		22.6 kHz		32 kHz
	Mean (SD)	value	Mean (SD)	value	Mean (SD)	value	Mean (SD)	value	Mean (SD)	value	Mean (SD)	value
At 1 day after NE
88 ()	4.00 (5.68)	0.3699	3.00 (8.56)	>0.9999	4.00 (4.59)	0.7544	4.50 (4.97)	0.131	5.50 (6.85)	0.2018	6.00 (13.08)	—
91 ()	2.73 (6.07)	>0.9999	6.00 (8.43)	0.357	5.00 (5.00)	0.5525	4.50 (9.26)	>0.9999	5.00 (8.50)	0.6249	8.50 (11.32)	—
94 ()	4.55 (6.88)	0.474	8.50 (10.55)	0.2195	5.91 (6.25)	0.0883	8.50 (7.84)	0.0525	9.00 (9.37)	0.0877	14.55 (7.23)	—
97 ()	7.50 (7.54)	0.0664	10.00 (8.79)	0.0468	15.83 (7.64)	0.0381	21.82 (8.15)	<0.0001	24.58 (7.82)	<0.0001	—	—
100 ()	5.50 (5.99)	0.1221	10.50 (5.99)	0.0025	24.50 (7.62)	0.0006	30.50 (7.25)	<0.0001	33.00 (9.19)	<0.0001	—	—
103 ()	6.25 (7.72)	0.1999	24.17 (9.49)	0.0002	34.17 (11.04)	0.0013	42.08 (9.16)	<0.0001	42.92 (7.82)	<0.0001	—	—
106 ()	13.75 (5.18)	0.0007	32.14 (4.88)	<0.0001	37.50 (5.35)	0.0006	47.86 (6.36)	<0.0001	50.00 (7.50)	<0.0001	—	—
At 14 days after NE
88 ()	-1.00 (5.16)	>0.9999	-1.50 (6.26)	>0.9999	0.50 (5.50)	>0.9999	-1.50 (5.80)	>0.9999	0.00 (8.16)	>0.9999	8.50 (10.55)	—
91 ()	-0.50 (7.62)	>0.9999	2.00 (7.53)	>0.9999	1.50 (6.26)	>0.9999	1.00 (3.94)	>0.9999	0.45 (8.79)	>0.9999	10.91 (8.61)	—
94 ()	1.00 (8.43)	>0.9999	2.00 (8.56)	>0.9999	-1.00 (7.38)	>0.9999	-1.00 (6.58)	>0.9999	1.50 (10.55)	>0.9999	12.73 (7.54)	—
97 ()	0.42 (5.42)	>0.9999	1.67 (6.85)	>0.9999	1.25 (6.78)	>0.9999	-0.42 (4.98)	>0.9999	6.25 (8.56)	0.321	—	—
100 ()	4.00 (6.99)	0.7272	2.50 (6.35)	>0.9999	1.50 (5.30)	>0.9999	4.00 (6.58)	0.6079	11.5 (9.44)	0.0273	—	—
103 ()	6.25 (8.56)	0.3317	2.92 (8.65)	>0.9999	6.25 (8.01)	0.2999	20.42 (8.38)	0.0003	40.00 (9.29)	<0.0001	—	—
106 ()	7.14 (6.36)	0.1267	15.71 (4.50)	0.0004	21.43 (5.56)	0.0002	41.43 (5.56)	<0.0001	46.67 (6.06)	<0.0001	—	—

Two-way ANOVA with Bonferroni post hoc tests were used to compare the difference between ABR thresholds at 1 day or 14 days after NE with the baseline in each group of intensity. Bold type: .