Tinnitus: Characterization of associated hearing loss and modalities of treatment

Natashya H Rent; Kiran M Bhojwani; Jayashree S Bhat; B Unnikrishnan

doi:10.4103/0971-7749.124513

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ORIGINAL ARTICLE

Year : 2013 | Volume : 19 | Issue : 4 | Page : 182-185

Tinnitus: Characterization of associated hearing loss and modalities of treatment

Natashya H Rent¹, Kiran M Bhojwani², Jayashree S Bhat³, B Unnikrishnan⁴
¹ Department of Otorhinolaryngology, Head and Neck Surgery, K.S. Hegde Medical Academy, Nitte University, Mangalore, India
² Department of Otorhinolaryngology, Head and Neck Surgery, Manipal University, Manipal, Karnataka, India
³ Department of Audiology, Speech and Language Pathology, Manipal University, Manipal, Karnataka, India
⁴ Department of Community Medicine, Kasturba Medical College, Manipal University, Manipal, Karnataka, India

Date of Web Publication

7-Jan-2014

Correspondence Address:
Natashya H Rent
Department of Otorhinolaryngology, Head and Neck Surgery, K.S. Hegde Medical Academy, Deralakatte, Mangalore - 575 018, Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/0971-7749.124513

Abstract

Purpose: To assess the characteristics of hearing loss with respect to tinnitus and to study the efficacy of various modalities of treatment of tinnitus. Design: Prospective study. Materials and Methods: Patients were assigned into three groups. All patients underwent a complete ENT examination, followed by pure tone audiometry, tinnitus matching, and tinnitus handicap inventory (THI) score. Patients were treated with gingko biloba, gabapentin, or tinnitus-retraining therapy (TRT) for a period of 6 weeks following which above investigations were repeated. Results: The study showed a positive correlation between tinnitus loudness matches and frequency of maximum hearing threshold (r = 0.687, P = 0.001) and a significant relation between tinnitus loudness matching and THI score (r = 0.383, P = 0.001). However, no correlations were observed between pitch match frequency and THI scores. Gingko biloba and TRT were found to be effective in the management of tinnitus (P < 0.01), but no improvement was observed with gabapentin therapy (P = 0.051). Conclusion: Tinnitus loudness matches near the threshold of frequency of maximum hearing loss, thus indicating that as threshold of hearing increases, the perception of tinnitus loudness increases. However, pitch match frequency does not affect severity of tinnitus. Gingko biloba and TRT are useful in the treatment of tinnitus.

Keywords: Gabapentin, Gingkobiloba, Tinnitus, Tinnitus handicap score, Tinnitus retraining therapy

How to cite this article:
Rent NH, Bhojwani KM, Bhat JS, Unnikrishnan B. Tinnitus: Characterization of associated hearing loss and modalities of treatment. Indian J Otol 2013;19:182-5

How to cite this URL:
Rent NH, Bhojwani KM, Bhat JS, Unnikrishnan B. Tinnitus: Characterization of associated hearing loss and modalities of treatment. Indian J Otol [serial online] 2013 [cited 2021 Apr 16];19:182-5. Available from: https://www.indianjotol.org/text.asp?2013/19/4/182/124513

Introduction

"Tinnitus" stems from the Latin term "tinnire" which means "to ring" and may be defined as "a sound perceived for more than five minutes at a time, in the absence of any external acoustical or electrical stimulation of the ear and not occurring immediately after exposure to loud noise." The incidence of tinnitus is found to be around 15% and is usually associated with hearing loss. Although various pathologies have been explained, it is thought to be an auditory perception due to spontaneous activity, arising from an altered state of excitation or inhibition within the auditory system. ^[1] The first account of treatment of tinnitus goes all the way back to the Egyptians and continued throughout the middle ages and with the dawn of the Renaissance surgery is introduced into treatment of tinnitus. However to this day, no precise treatment has been identified. The present study was planned to have an insight into the characteristics of hearing loss with respect to tinnitus and the efficacy of various modalities of treatment of tinnitus.

Materials and Methods

A prospective study was carried over a period of 2 years from November 2009-October 2011 in the department of otolaryngology, head and neck surgery, in our institution, after obtaining ethical clearance from the institutional ethical committee. Convenient sampling was adopted for recruiting the participants. Informed consent was obtained from all participants prior to conduction of the study. The participants included 78 individuals based on the inclusion criteria such as age above 18 years; subjective tinnitus associated with sensorineural hearing loss and presence of tinnitus for more than 3 months. Patients with objective tinnitus, patients with tinnitus due to causes other than inner ear pathology and acoustic neuroma were excluded from the study. Each participant underwent a detailed history and clinical examination followed by a pure tone audiogram, obtained using calibrated Grason Stadler Inc 61 (GSI 61) clinical audiometer in a sound-treated room. Tinnitus handicap inventory (THI) score was administered on all participants, followed by an objective evaluation of tinnitus pitch and loudness matching using the ascending descending combined procedure. Following the assessment, participants were divided into three groups for management. The first group received gingko biloba 40 mg thrice daily, the second group received gabapentin 100 mg thrice daily and the third group underwent tinnitus retraining therapy (TRT). The goal of training was to habituate the participant to tinnitus. Initially, the participant was allowed to select the noise, music, or environmental sound of their choice. The participant was then asked to adjust the volume of sound to a comfortable level with intervals of tinnitus in the stimulus. Treatment protocol was administered for a period of 6 weeks. Following management, tinnitus handicap inventory was read ministered. The scores of pre- and post treatment were compared and evaluated for both groups. The collected data were entered in Microsoft excel and statistical analysis was done using SPSS version 11.5. Paired t-test was done and P < 0.05 was taken as statistically significant.

Results

A total of 78 individuals (39 males and 39 females) participated in the study within the age range of 18-82 years. Most participants were between 25 and 44 years, with least participation below 25 years [Table 1].

Table 1: Pitch matches across different age groups of individuals with tinnitus

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A descriptive analysis of pitch match data revealed that in majority 20.51% (16) of patients, tinnitus frequency had matches at 250 Hz, followed by 14.1% (11) at 4000 Hz. Tinnitus match was minimal at midoctaves 750 Hz, 1500 Hz, and 3000 Hz, and least at 12000 Hz [Table 1].

Among the study population, 35.9% (28) had a THI score ranging from 38 to 56 (moderate tinnitus), 32.1% (25) with a score ranging from 18 to 36 (mild tinnitus) with only a small number of participants (5.2%; 4 cases) having scores ranging between 78 and 100 (catastrophic tinnitus) [Table 2].

Table 2: Distribution of the tinnitus handicap inventory scores across the total number of patients

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A comparison between tinnitus pitch matching frequency and THI scores for the participants in both the ears failed to demonstrate significant correlation (r = −0.019, P = 0.87). However, a significant correlation (r = 0.383, P = 0.001) was observed between tinnitus loudness matching intensity and THI scores in both the ears as seen in [Figure 1].

Figure1: Scatter plot for tinnitus handicap score against tinnitus loudness match intensity

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The study also attempted to find a relationship between the pure tone thresholds and tinnitus loudness matching intensity. In participants with unilateral tinnitus, the tinnitus ear was considered the test ear, and in participants with bilateral tinnitus, the ear with louder tinnitus was considered as the test ear. On analyzing the data, it was found that 75.4% of participants showed loudness matches near the threshold of frequency at which they had maximum hearing loss. On statistical analysis, a positive correlation was observed at the tinnitus loudness matches obtained at the frequency of maximum hearing threshold (r = 0.687, P = 0.001). This indicates that as threshold of hearing increased, the perception of tinnitus loudness also increased [Figure 2].

Comparing THI scores before and after 6 weeks of management using gingko biloba, gabapentin, and TRT using paired t-test revealed a significant difference (P < 0.001) between pre- and post management scores after treatment with gingko biloba and TRT but not with gabapentin (P = 0.051) [Table 3].

Figure 2: Scatter plot for tinnitus loudness match against threshold at pitch match frequency

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Table 3: Comparison between pre- and posttreatment tinnitus handicap inventory score in the three treatment groups

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Discussion

Tinnitus, which is thought to be a phantom auditory perception, is a phenomenon that has been described centuries ago. In ancient China, it had been regarded as sensitivity to the divine; however, ancient Egyptians and Mesopotamians believed that tinnitus occurred in a bewitched ear. It was also reported that Charles Darwin who suffered from tinnitus kept records of its daily amplitude and frequency. However, to this day the pathophysiology has not been explained and no precise treatment has been found.

The current study attempted to explore relationship between the pure tone thresholds and tinnitus loudness matching intensity and found a positive correlation between tinnitus loudness matches obtained at the frequency of maximum hearing threshold indicating that as threshold of hearing increases, the perception of tinnitus loudness increases.

Tinnitus pitch matches obtained did not follow any specific pattern of matches. However, it was found that 71.8% of the participants had tinnitus matches at or below 2000 Hz. Results of this study are in consonance with that of Pan et al., ^[2] who found that patients with a tone like tinnitus reported a higher pitch compared to those with a noise like tinnitus, who have a pitch less than 2000 Hz. They also concluded from their study that there was no relationship between tinnitus pitch match either across individuals or with audiogram variables.

In the current study, there was no correlation between pitch match frequency and THI scores, but a significant correlation was observed between tinnitus loudness matching and the THI scores. Searchfield et al., ^[3] studied the impact of hearing loss on tinnitus severity index, and although the study did not report statistically significant correlation with any of the variables of the audiogram for the tinnitus severity index, some aspects of the pure tone audiometry, especially the elevated low frequency thresholds correlated with greater tinnitus handicap. Steinmetz et al., ^[4] studied the interference of tinnitus on the quality of life of individuals in a noise exposed working condition using a Brazilian version of the THI and found that there was a relationship between the total score of THI and the functional, emotional, and catastrophic tinnitus.

Gingko biloba extracts which have been used for centuries in traditional Chinese medicine, have been proposed as cognitive enhancers and for treatment of a large number of pathologies of the central nervous system for their biological effects such as neuroprotection. ^[5] While comparing the pre- and post treatment THI scores after 6 weeks of management using gingko biloba, current study revealed a significant difference between pre- and post management scores (P < 0.001). Results of former studies with one exception have collectively suggested that extracts of ginkgo biloba were effective in treating tinnitus. ^[6] Only the results of a double blind, placebo-controlled trial involving 1121 healthy people aged between 18 and 70 years with tinnitus who were treated with 50 mg of gingko biloba thrice daily for a period of 12 weeks had showed no significant difference between the study and placebo groups. ^[7]

Zapp ^[8] has reported the effectiveness of gabapentin in a patient who was tinnitus-free for 23 days in a month and experienced a 75% decrease in symptoms during the remaining days. On follow-up after 2 years, he remained free of symptoms on 500 mg/day of gabapentin. Shulman ^[9] used gabapentin in combination with klonopin for its purported GABAergic inhibitory effect and showed similar results. Piccirillo et al., ^[10] in a double-blinded, randomized control trial compared the effectiveness of gabapentin in the treatment of tinnitus for a period of 8 weeks in comparison to placebo and found that gabapentin was no more effective than placebo. Paired t-test analysis of results of this study also revealed no significant difference between pre- and post management scores.

Henry et al., ^[11] have stated that the goal of TRT is to induce habituation to the tinnitus, using two strategies which include removal of any negative thoughts or fears that may be associated with the tinnitus perception through counselling and removal of tinnitus from conscious perception by means of sound therapy. Another study has compared the effectiveness of various environmental sounds of nature, water, and air and found that all of the sounds provided a significant reduction in tinnitus annoyance. ^[12] However, the sounds of nature and water were judged significantly more effective than the other sounds. Jastreboff and Jastreboff ^[13] have shown that tinnitus improvement is usually observed by the third month following initiation of treatment, with majority of patients achieving a high level of tinnitus control after 12 months of treatment. Berry et al., ^[14] in their study showed a significant improvement in self-perceived disability following TRT as measured by the THI. Baseline analysis revealed significant correlation between subjective presence of hyperacusis and higher total, emotional, and catastrophic THI scores.

Following 6 months of TRT, the total, emotional, functional, and catastrophic THI scores showed significant improvement. Loudness discomfort levels also significantly improved (P = 0.02). These results are similar to our study which showed a significant improvement in tinnitus as measure by THI (P = 0.01) although our study was carried out for a period of 6 weeks.

The limitation of our study was the duration of treatment, as treatment was carried out for a period of 6 weeks and long-term follow-up was not achieved.

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