Table 2.

Studies Demonstrating a Statistically Significant Deleterious Effect of ASA on Pure-tone Thresholds or Speech Discrimination in Patients without Inflammatory Conditions.

Author, Year	Study Design (sample size)	Patient Description	ASA Regimen Evaluated	Hearing Evaluation	Follow-up Time	ASA Exposure Results	No ASA Exposure Results	Time from Exposure to Outcome	Additional Comments
Abdala, 200523	Prospective cohort (n = 41, 10 of which were ASA exposed)	Adult ASA recipients: age 22–37 years (n = 10) Children with mild SNHL (n = 8) Healthy term–born neonates (n = 23)	ASA 975 mg (3 tablets of 325 mg) Q6h for 4 d	Air and bone conduction audiogram Immittance testing DP-gram DPOAE	Baseline, then 72 h and 96 h afterward	Mean audiometric threshold increase at 96 h: 12.7 dB at 1500 Hz, 14.3 dB at 6000 Hz. Significant correlation between serum level and audiometry (r = 0.75, P = .19)	Subjects were compared to their own baseline	72,96 h	Audiometric results were not directly correlated with DPOAE results
Day, 198925	Prospective cohort, double-blinded (n = 8)	Age 22–46 years with normal hearing at the outset Male healthy volunteers	ASA in 4 serial scheduled doses: (1) 1.95 g/d (2) 3.25 g/d (3) 4.55 g/d (4) 5.85 g/d for 7 d each	Pure-tone thresholds measured at 250–8000 Hz	On the seventh day of each treatment period	Mean HL per frequency (dB HL) 1.95g/d = 4.38 3.25g/d = 11.56 4.55g/d = 40.56 5.85g/d= 112.5 Mean Tinnitus intensity (dB HL) 1.95g/d = 25.50 3.25 g/d= 36.38 4.55 g/d= 51.00 5.85 g/d= 62.13	Subjects were compared to their own baseline. HL expressed as mean decrease from pretreatment thresholds in both ears	Effect present at 1 week	Hearing and tinnitus had a dose-dependent response to ASA level (P < .05).

Abbreviations: ASA, aspirin (acetylsalicylic acid); DPOAE, distortion product otoacoustic emissions; HL, hearing loss; SNHL, sensorineural hearing loss.