Changes in late-latency auditory evoked potentials after tinnitus suppression using auditory stimulation

Abstract Objective: Tinnitus can result from auditory system reorganization due to neural activity dysfunctions. Auditory stimulation can cause temporary or persistent tinnitus alleviation by altering the neural generators. The present study investigated the changes in Late-Latency Auditory Evoked Potentials (LLAEPs) after tinnitus suppression using auditory stimulation with short-term Residual Inhibition (RI) and long-term Tinnitus Masker (TM). Methods: The study included 40 participates with equal numbers in the Tinnitus Group (TG), including the chronic tinnitus subjects, and the Control Group (CG), including matched volunteers. The participants had normal hearing in conventional audiometry. All the participants underwent LLAEP recording pre-intervention and after a one-minute auditory stimulation (RI), as well as a pre-intervention Dichotic Digit Test (DDT) as a behavioral assessment of the selective attention. Moreover, TG underwent a 3-month course of TM, a third LLAEP recording post-TM, a second DDT post-TM, and the Tinnitus Handicap Inventory (THI) before and after the TM. Results: In the baseline LLAEP recording, the TG had significantly later N1, P3a, and P3b latencies, as well as significantly lower P3a and P3b amplitudes. The second LLAEP recording showed a significant intragroup increase in P3a amplitude and a significant decrease in P3a latency in the TG, while no significant intragroup difference was observed in the CG. In the third LLAEP recording performed on TG, the P3a amplitude and latency had significant changes compared to the second recording, while the N1 latency was significantly decreased. Moreover, the DDT and THI scores had significant improvement after the TM in TG. Conclusions: The present study showed the neurophysiological changes after short-term (RI) and long-term (TM) auditory stimulations in tinnitus subjects. The LLAEP changes suggest that these interventions lead to tinnitus suppression through common mechanisms. The electrophysiological observation was also confirmed using behavioral assessments. Level of evidence: This study type is a "comparative study" with the level of evidence "3".

Cortical Reorganization Following Psychoeducational Counselling and Residual Inhibition Therapy (RIT) in Individuals with Tinnitus

Abstract Introduction Psychoeducational counselling and residual inhibition therapy (RIT) are traditional approaches used in many clinics to manage tinnitus. However, neurophysiological studies to evaluate posttreatment perceptual and functional cortical changes in humans are scarce. Objectives The present study aims to explore whether cortical auditory-evoked potentials (CAEPs; N1 and P3) reflect the effect of modified RIT and psychoeducational counselling, and whether there is a correlation between the behavioral and electrophysiological measures. Methods Ten participants with continuous and bothersome tinnitus underwent a session of psychoeducational counselling and modified RIT. Perceptual measures and CAEPs were recorded pre- and posttreatment. Further, the posttreatment measures were compared with age and gender-matched historical control groups. Results Subjectively, 80% of the participants reported a reduction in the loudness of their tinnitus. Objectively, there wasasignificant reductioninthe posttreatment amplitude of N1 and P3, with no alterations in latency. There was no correlation between the perceived difference in tinnitus loudness and the difference in P3 amplitude (at Pz). Conclusion The perceptual and functional (as evidenced by sensory, N1, and cognitive, P3 reduction) changes after a single session of RIT and psychoeducational counselling are suggestive of plastic changes at the cortical level. The current study serves as preliminary evidence that event-related potentials (ERPs) can be used to quantify the physiological changes that occur after the intervention for tinnitus.

An Analysis of the Masking Curves and Residual Inhibition Effects of Tinnitus Patients at Different Age with Less Severe Hearing Loss / 听力学及言语疾病杂志

Objective To investigate the relationships between tinnitus masking curve types and tinnitus re-sidual inhibition in the patients at different ages with normal hearing ,mild ,moderate severe hearing loss .Methods The minimum masking levels and residual inhibition of 335 patients with normal hearing ,mild to medium ,and mod-erate to severe hearing loss were tested and analyzed using the method of psychological acoustics .Results Ages and the duration of residual inhibition had a corresponding relationship :the 19～30 years old group had corresponding relations with 0～40 seconds of residual inhibition ,while the 31～50 years old group with 81～100 seconds of resid-ual inhibition ,and the 50～63 years old group with 101～200 seconds of residual inhibition ,respectively .The 31～50 years old group and 51％ ～80％ residual inhibition had a corresponding relationship ;0％ ～30％ residual inhibi-tion group and parallel type of tinnitus masking curves had a corresponding relationship ,31％ ～50％ residual inhibi-tion group and separation type of the tinnitus masking curves had a corresponding relationship ,the groups of 51％ ～80％ and 81％ ～100％ residual inhibition with the types of convergent and overlapping tinnitus masking curves had corresponding relationship ,respectively .Conclusion There were different characteristics of tinnitus masking patients at different ages with different levels of hearing loss .The older people are ,the better effects and longer time of residual inhibition are .Those tinnitus patients with the tinnitus masking curve of convergent type and overlapping type showed a better tinnitus masking effect than the others .

Tailor-made Complex Sound Alleviates both Residual-Inhibition Positive and Negative Tinnitus Patients with Normal Hearing Audiogram / 中山大学学报(医学科学版)

[Objective] To evaluate the efficacy of sound therapy and provide a kind of treatment for tinnitus patients with normal audiogram.[Methods] From the database of the Audiometric Center of the First Affiliated Hospital,Sun Yat-sen University,we identified 46 outpatients with normal hearing thresholds in the conventional pure-tone audiometry suffering subjective tinnitus over 3 months.The clinical information were collected with respect of age,gender,tinnitus severity,pitch,laterality and duration,comorbid symptoms.All the patients received the tinnitus test,including loudness and frequency of the tinnitus and residual inhibition,Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) scores pre-and post-complex sound therapy.The complex sound were remixed with natural sounds and music materials,while the masking frequency of natural sounds is consistent with the tinnitus frequency of patients and the main frequency of music materials covers the tinnitus frequency.[Results] 32 of the 46 patients showed residual inhibition (RI) positive.The average THI score before treatment was 33.38±16.23 and the VAS score was 4.38±1.62.The THI score decreased to 21.75±11.67 and the VAS score was 2.97±1.06 after sound therapy.The rest 14 patients were residual inhibition (RI) negative.The THI score were 29.86±20.15 and 23.43±16.29 pre-and post-complex sound therapy,while the VAS score were 3.93±1.69 and 3.36±1.2.The THI and VAS scores were significantly decreased after the treatment in both RI positive and negative patients.The RI positive group showed better results than RI negative group.[Conclusions] Both RI positive and negative tinnitus with normal audiometry shown adaptation with complex sound therapy,RI positive patients acquired more benefits from tailor-made complex sound therapy.