Evaluation of Tinnitus and Hearing Loss
Evaluation of tinnitus severity: Tinnitus in the patients was classified into seven grades according to the Feldmann standard (6): 1) 0: No tinnitus, 2) 1: Occasional tinnitus that does not affect the patient’s daily life, 3) 2: Persistent tinnitus that is more prominent in quiet surroundings, 4) 3: Persistent tinnitus even in a noisy environment, 5) 4: Persistent tinnitus combined with attention and sleep disorders, 6) 5: Persistent severe tinnitus affecting the patient’s ability to work, and 7) 6: Severe tinnitus provoking suicidal tendencies.
Efficacy evaluation of tinnitus: The evaluation was based on the Chinese classification of tinnitus severity(6),: 1) Cured: Tinnitus had disappeared or improved to grade 1, 2) Markedly effective: Tinnitus was alleviated by 1-3 grades but had not yet reached grade 1, 3) Effective: Tinnitus was alleviated to some extent but remained in the same grade, 4) Ineffective: Tinnitus was unchanged or even worsened. In this study, level 1 intermittent tinnitus was also counted as cured in this article.
Grades of hearing loss severity: The hearing thresholds at 0.50, 1.00, 2.00, and 4.00 kHz were measured. When the hearing thresholds at some frequencies could not be detected, the frequency threshold was considered the maximum audiometric intensity. The degrees of hearing loss were categorized as mild (26–40 dB HL), moderate (41–60 dB HL), severe (61–80 dB HL), and profound hearing loss (> 80 dB HL) (17).
Classification of hearing loss: Four audiogram shapes were defined in relation to the pattern of hearing loss (17): ascending, flat, profound, and descending. “Ascending” referred to cases in which the average threshold of 0.25 to 0.5 kHz was 20 dB higher than normal. When the difference in the hearing threshold did not exceed 20 dB at any frequency, the audiogram shape was classified as “flat.” For patients with a flat audiogram and a hearing threshold greater than 81 dB, the audiogram shape was classified as “profound.” The audiogram shape was described as “descending” when the average threshold of 4 to 8 kHz was 20 dB higher than normal.
Hearing recovery evaluation: Based the results of pure-tone audiometry (17) patients were divided into four groups: 1) Cured: A final hearing level less than 25 dB regardless of the size of the gain, 2) Markedly effective: Greater than 30 dB of gain for the average hearing threshold, 3) Effective: Gains greater than 15 dB and less than 30 dB, and 4) Ineffective: less than 15 dB of gain.