Table 2.

Comparison of hearing thresholds (dB HL) between groups.

Frequency (Hz)	Study group (n = 39)	Control group (n = 36)	p-valuea
	Md (P25–P75)	Md (P25–P75)
250	5 (2.5–7.5)	5 (0–5)	0.036
500	5 (2.5–10)	5 (2.5–7.5)	0.055
1000	2.5 (0–5)	2.5 (0–2.5)	0.042
2000	5 (2.5–7.5)	3.8 (0–5)	0.092
3000	5 (2.5–7.5)	5 (2.5–5)	0.444
4000	5 (2.5–7.5)	5 (2.5–6.9)	0.313
6000	7.5 (5–12.5)	7.5 (5–10)	0.533
8000	7.5 (5–15)	5 (2.5–7.5)	0.003
Mean 250–8000 Hz	5.9 (3.4–8.1)	4.4 (2.3–5.9)	0.016
9000	5 (2.5–15)	5 (2.5–7.5)	0.022
10,000	5 (2.5–10)	2.5 (0–5)	0.002
11,200	7.5 (2.5–15)	5 (2.5–7.5)	0.096
12,500	5 (2.5–10)	2.5 (0–5)	0.034
14,000	2.5 (0–12.5)	0 (0–2.5)	0.160
16,000	2.5 (0–22.5)	0 (0–0)	<0.001
Mean 9000–16,000 Hz	4.6 (2.9–11.7)	2.9 (1.8–5.0)	0.005

^aMann–Whitney test.