Acoustic therapies including hearing aids and tinnitus control instruments are widely
used in Japan but without high levels of evidence. The outpatient hearing aid clinic
at our institution fits patients with hearing aids and instructs patients on how to
use them to control tinnitus if present. In this study, we examined the effects of
this approach on tinnitus.
One hundred and eleven of 138 patients who visited our hearing aid clinic from April
2016 to September 2018 purchased hearing aids after fitting. Sixty-six of these patients
(31 men, 35 women; mean age 78.0 ± 8.0 years) had both hearing loss and tinnitus and
were enrolled. The tinnitus was bilateral in 41 patients and unilateral in 25 (poor
hearing ear, n = 16, good hearing ear, n = 9). Hearing aids were worn bilaterally by 23 patients and unilaterally by 43 (89
devices). Seventeen of the 23 patients wearing bilateral hearing aids had bilateral
tinnitus and 6 had unilateral tinnitus, i.e., in 40 ears, the tinnitus side matched
the hearing aid side (40 devices) and in 6 ears did not (6 devices). Twenty-four of
43 patients wearing unilateral hearing aids had bilateral tinnitus, meaning that in
24 ears the tinnitus side matched the hearing aid side (24 devices). In six of the
remaining 19 cases with unilateral tinnitus, the hearing aid and tinnitus were on
the same side (6 devices) and in 13 were on opposite sides (13 devices). Changes in
the Tinnitus Handicap Inventory (THI), visual analog scale (VAS, for tinnitus discomfort,
severity, and persistence), and Hospital Anxiety and Depression Scale scores were
measured immediately before using a hearing aid and 12 months later.
Significant effects of hearing aids on tinnitus were observed in all subjects (THI,
p = 0.0000030), VAS (severity, p = 0.000000066; discomfort, p = 0.0000013). Significant effects were observed with bilateral hearing aids (THI,
p = 0.0012; VAS for severity, p = 0.00069; VAS for discomfort, p = 0.00052) and with unilateral hearing aids (THI, p = 0.00055; VAS for severity, p = 0.000034; VAS for discomfort, p = 0.00007). Spearman's rank correlation coefficient showed a significant positive
correlation between the THI and VAS scores (p = 0.0033). In cases of bilateral tinnitus, significant differences were observed
with bilateral hearing aids (THI, p = 0.011; VAS for severity, p = 0.0019; VAS for discomfort; p = 0.020) and with unilateral hearing aids (THI, p = 0.00069; VAS for severity, p = 0.00071; VAS for discomfort, p = 0.000093).
Acoustic therapy using hearing aids was effective for tinnitus. Even when bilateral,
a unilateral hearing aid is able to improve tinnitus. When unilateral, the ipsilateral
hearing aid is able to improve tinnitus.