Tinnitus is defined as the perception of an audible sound in the absence of an external stimulus or source. It is the most frequent otological symptom reported in clinical practice. It can manifest itself in the form of ringing, buzzing, hissing, or roaring and can severely affect the quality of life because it causes sleeping disorders, lack of concentration, anxiety, and depression (1). Tinnitus has been broadly categorized into objective and subjective, with the latter being more prevalent. Cochlear origin tinnitus is a common attribute of subjective tinnitus and is believed to be caused by outer or inner hair cells' dysfunction, abnormal spontaneous neural activity, or impaired cochlear neurotransmission (2). The pathophysiology of tinnitus is complex and often multifactorial. Peripheral cochlear injury can result in distortions in afferent stimulation of the central auditory system, causing maladaptive neural plasticity and hyperactivity in the auditory pathways (3). The understanding of the pathophysiology of the condition has led to the exploration of different modalities of treatment, which would modify cochlear or neural activity. Despite several therapeutic approaches such as sound therapy, pharmacotherapy, counseling, and neuromodulation, there is no common and universal effective treatment (4). Intratympanic delivery of drugs has been used as a targeted therapy to manage inner ear diseases, such as tinnitus, acute sensorineural hearing loss, and Menière’s disease. This route enables the high levels of drugs to be delivered to the cochlea by diffusion through the round window membrane with minimal systemic adverse effects (5). The agents that have been studied in terms of their use in the management of tinnitus are dexamethasone and lidocaine when used intratympanically. Dexamethasone is a powerful corticosteroid that is anti-inflammatory, anti-edematous, and immunosuppressive. Glucocorticoid receptors are well distributed throughout the cochlea, and there is some evidence that, in the cochlea, the steroids can help maintain cochlear homeostasis, alleviate inflammation, stabilize cell membranes, and suppress aberrant neural activity (6). A number of clinical trials have shown inconsistent yet encouraging recovery in the level of tinnitus after intratympanic injection of dexamethasone (7). Lignocaine is a local anesthetic and sodium channel blocker. It has been shown to inhibit spontaneous neural activity in auditory nerve fibers. Its action in tinnitus is due to the inhibition of hyperirritable cochlear or auditory nerve activity, leading to a reduction of abnormal auditory perception (8). Despite the fact that systemic lidocaine has been linked to temporary relief of tinnitus, intratympanic delivery has the ability to act locally with a reduced number of systemic side effects. However, short-term vertigo and discomfort have been noted as a result of the action of an anesthetic agent on the vestibular apparatus (9). The recent studies have compared tinnitus treatment by application of intratympanic lidocaine and dexamethasone. It is indicated that, in combination with dexamethasone, it can be more effective than steroid therapy alone in improving the symptoms, potentially because of a complementary effect on cochlear inflammation and neural hyperactivity (10). However, the findings of various studies are inconclusive, and the best agent to treat tinnitus caused by cochlear damage is still controversial. Since tinnitus is a chronic condition it affects the quality of life, and there is no established set of guidelines to follow, a comparative study of intratympanic lidocaine versus dexamethasone should be done. The present study was done to evaluate the efficacy of Lidocaine versus dexamethasone, which are commonly used intratympanic agents for the treatment of tinnitus of cochlear origin.

This was a prospective, comparative, interventional study conducted in the Department of Otorhinolaryngology, Rajiv Gandhi Institute of Medical Science (RIMS), Adilabad, Telangana. Institutional ethics was obtained from the Institutional Ethics Committee. Written informed consent was obtained from all the participants of the study after explaining the nature of the study in the vernacular language. Inclusion Criteria 1. Diagnosed with subjective tinnitus of cochlear origin 2. Duration of tinnitus of more than 3 months 3. Pure tone audiometry suggests cochlear pathology 4. Aged 18 – 60 years 5. Males and females 6. Those willing to participate voluntarily by signing an informed consent form Exclusion Criteria 1. Tinnitus of retrocochlear or central origin 2. Objective tinnitus 3. Prior history of ear surgeries 4. Middle ear infection with tympanic membrane perforation 5. Hypersensitivity to lignocaine or dexamethasone 6. Pregnant and lactating females 7. Not available for follow-up. Based on the inclusion and exclusion criteria during the study period, a total of n=40 patients diagnosed with subjective tinnitus of cochlear origin were included based on the convenience sampling method. The selected patients were randomly allocated to two groups of n=20 each by using computer-generated random numbers. Group A (n = 20): Intratympanic Lidocaine Group. Patients in this group received an intratympanic injection of 2% lidocaine, administered under aseptic precautions. Group B (n = 20): Intratympanic Dexamethasone Group. Patients in this group received intratympanic injection of dexamethasone (4 mg/ml) under similar conditions. After allocation, all patients were subjected to detailed history taking followed by clinical examination, which included otoscopic examination. The baseline pure tone audiometry, tympanometry, and routine laboratory investigations were performed in all cases. The severity of tinnitus was estimated by using the Tinnitus Handicap Inventory (THI) score before treatment. Procedure of drug injection: This procedure was performed with patients in a supine position with the treating ear upwards. Under aseptic precautions, topical anesthesia was applied to the external auditory canal. Using an insulin syringe, 0.3–0.5 ml of the study drug was injected slowly through the posterior inferior quadrant of the tympanic membrane. The patients were left in the same position for approximately 30 minutes to allow diffusion of the drug through the round window membrane. All patients received one intratympanic injection per week for three consecutive weeks. Patients were advised to avoid swallowing and talking during the immediate post-procedure period. Follow-Up and Outcome Assessment: Patients were followed up at 1 week, 4 weeks, and 12 weeks after completion of therapy. The primary outcome measure was improvement in tinnitus severity assessed using the THI score. Secondary outcome measures included patient-reported subjective improvement and occurrence of any adverse effects such as vertigo, ear pain, or transient hearing loss. Statistical Analysis: All the available data were segregated, refined, and uploaded to an MS Excel spreadsheet and analyzed by SPSS version 26 in Windows format. The continuous variables were represented as mean, standard deviation, frequency, and percentages. The categorical variables were compared by application of the t-test for differences in the mean of two groups. Chi-square test was used to determine differences between two groups, and values of p <0.05 were considered statistically significant.

Baseline characteristics of the study cohort are given in Table 1. A critical analysis of the table showed that the mean age of patients in Group A was 48.2 ± 8.5 years, while in Group B it was 49.7 ± 9.1 years, with no statistically significant difference between the two groups (p = 0.624). The distribution of cases by gender between the two groups was comparable, with males distributed 55% in group A and 60% in group B, and no significant differences in distribution. The mean duration of tinnitus in Group A was 11.5 ± 4.8 months, while in Group B it was 12.8 ± 5.2 months, and the difference was not significant (p = 0.418). Based on laterality, unilateral tinnitus was common in both groups, with no significant differences between the groups. The tinnitus handicap inventory (THI) scores at baseline of Group A were (58.4 ± 12.3) compared to Group B (56.9 ± 11.8). Audiological parameters, including mean pure tone average and tympanometry findings, were also comparable, with all patients demonstrating Type A tympanograms. Intra-Group Comparison of THI Scores during follow-up visits is depicted in Table 2. Analysis of the table showed that Group A (lidocaine) cases had baseline values of 58.4 ± 12.3, which were reduced to 52.1 ± 13.5 at 1 week. Similarly, the values reduced to 49.8 ± 14.2 at 4 weeks and 51.4 ± 13.8 at 12 weeks. The mean reduction from the baselines was 6.3 points at 1 week to 8.6 points at 4 weeks. All the values were found to be statistically significant. However, a slight increase in THI score was noted at 12 weeks, suggesting a partial loss of sustained benefit. Group B (dexamethasone) demonstrated a more significant and sustained reduction in THI scores. The mean THI score decreased from 56.9 ± 11.8 at baseline to 45.3 ± 10.7 at 1 week, 38.5 ± 9.4 at 4 weeks, and 37.2 ± 8.9 at 12 weeks. The mean reduction from baseline increased progressively, reaching 19.7 points at 12 weeks. All reductions were highly statistically significant (p < 0.001), indicating superior and sustained intra-group improvement with dexamethasone. Table 1: Baseline Characteristics of the Study Population (N=40) Characteristic Group A: Lidocaine (n=20) Group B: Dexamethasone (n=20) p-value Demographics Age (years), Mean ± SD 48.2 ± 8.5 49.7 ± 9.1 0.624 Gender, n (%) 0.752 Male 11 (55%) 12 (60%) Female 9 (45%) 8 (40%) Tinnitus Profile Duration of Tinnitus (months), Mean ± SD 11.5 ± 4.8 12.8 ± 5.2 0.418 Unilateral / Bilateral, 15 / 5 16 / 4 0.711 Baseline THI Score, Mean Audiological Profile ± SD 58.4 ± 12.3 56.9 ± 11.8 0.705 Mean PTA (dB HL), Mean ± SD* 42.3 ± 10.1 40.8 ± 9.5 0.635 Tympanometry (Type A), n (%) 20 (100%) 20 (100%) 1.000 *PTA: Pure Tone Average (0.5, 1, 2, 4 kHz). Table 2: Intra-Group Comparison of Tinnitus Handicap Inventory (THI) Scores Across Follow-up Visits Group Baseline THI Mean ± SD I-Week Post-Treatment Mean ± SD 4-Week Post-Treatment Mean ± SD 12-Week post-treatment Mean ± SD Group A: Lidocaine 58.4 ± 12.3 52.1 ± 13.5* 49.8 ± 14.2** 51.4 ± 13.8** Mean Reduction from Baseline - -6.3 -8.6 -7.0 Group B: Dexamethasone 56.9 ± 11.8 45.3 ± 10.7*** 38.5 ± 9.4*** 37.2 ± 8.9*** Mean Reduction from Baseline - -11.6 -18.4 -19.7 Intra-group comparison vs. Baseline: *p < 0.05, **p < 0.01, **p < 0.001. Inter-group comparison of treatment efficacy is depicted in Table 3. At different follow-ups, it was found that Group B showed significantly greater reduction in THI scores compared to Group A. At 1 week, the mean THI reduction was 11.6 ± 6.8 in Group B versus 6.3 ± 5.1 in Group A (p = 0.008). This difference became more pronounced at 4 weeks and 12 weeks, with Group B demonstrating nearly double the reduction in THI scores (p < 0.001). Responder analysis at 12 weeks revealed that 75% of patients in the dexamethasone group met the criteria for clinical response compared to only 40% in the lidocaine group (p = 0.025). Additionally, the mean percentage improvement at 12 weeks was significantly greater in Group B (34.6 ± 15.2%) compared to Group A (12.0 ± 11.8%), further supporting the superior efficacy of dexamethasone. Subjective outcomes and adverse effects in the two groups of cases are given in Table 4. Group B showed (60% vs. 25%) a much greater percentage of patients identifying significant subjective improvement (p = 0.022). On the other hand, the lidocaine group showed mild improvements or no improvement at all. In terms of safety, it is reasonable to say that adverse effects were more common in Group A (45%) than in Group B (20%), but this observation was not significant (p = 0.091). Transient vertigo or dizziness was much more frequent in the lidocaine group (30%) than in the dexamethasone group (5%) (p = 0.042). The other adverse effects, like fullness of the ear and temporary hearing loss, were mild and self-limiting, and they did not display any significant inter-group differences. The two groups had no cases of otitis media. Table 3: Inter-Group Comparison of Treatment Efficacy Based on THI Score Reduction Outcome Parameter Group A: Lidocaine (n=20) Group B: Dexamethasone (n=20) p-value (Unpaired t-test) Mean THI Reduction at 1 Week 6.3 ± 5.1 11.6 ± 6.8 0.008 Mean THI Reduction at 4 Weeks 8.6 ± 7.2 18.4 ± 8.3