Diagnosis and treatment of sudden sensorineural hearing loss

Table 1 Criteria for the grading of hearing loss in sudden sensorineural hearing loss

Grade 1	PTA < 40 dB
Grade 2	40 dB ≤ PTA < 60 dB
Grade 3	60 dB ≤ PTA < 90 dB
Grade 4	90 dB ≤ PTA

Evaluation of the initial audiogram should be performed within 2 wk of onset. PTA: Arithmetic mean of the five frequencies: 250, 500, 1000, 2000, and 4000 Hz.

Table 2 Final grades of initial grade 4 cases in five nationwide sudden sensorineural hearing loss surveys in Japan n (%)

	1972	1987	1993	2001	2012
Grade 1	26 (14)	49 (18)	70 (18)	25 (15)	5 (21)
Grade 2	31 (16)	44 (17)	62 (16)	36 (22)	1 (4)
Grade 3	87 (46)	119 (45)	173 (43)	68 (41)	11 (46)
Grade 4	45 (24)	53 (20)	95 (24)	38 (23)	7 (29)
Total	189 (100)	265 (100)	400 (100)	167 (100)	24 (100)

The data for 1972, 1987, and 1993[2], 2001[3], and 2012[1] are summarized.

Table 3 Percentages of patients who received steroids, vitamins, stellate ganglion block, hyperbaric oxygen therapy, or prostaglandin E₁ for sudden sensorineural hearing loss

	1972	1987	2001
Steroids	88%	93%	85%
Vitamins	88%	93%	92%
SGB	24%	27%	8%
HBO	3%	12%	11%
PGE1	0%	11%	33%

Data for 1972 and 1987[4], and 2001[3] are summarized. SGB: Stellate ganglion block; HBO: Hyperbaric oxygen therapy; PGE₁: Prostaglandin E₁.