The effect of loudness balancing method in cochlear implant users

Cochlear implant (CI) users may experience impaired auditory performance if sounds are perceived as irregular, gravelly, or excessively echoed due to imbalances in volume at higher stimulation levels. Loudness balancing should be performed after fitting to overcome these problems. It was hypothesized that programming based on behavioral loudness balancing would lead to improved music perception, speech comprehension, and spectral-temporal resolution; furthermore, we postulated that these scores would exhibit a correlation. The study included 26 unilateral Med-EL CI users. Each participant was assessed using two different CI programs, which were determined using behavioral loudness balancing (P2) and electrically evoked stapedial reflex threshold (P1). The outcomes of the following assessments were compared: speech perception was evaluated using the Turkish Matrix Sentence Test (TURMatrix); spectral temporal resolution abilities were assessed using the Random Gap Detection Test (RGDT) and Spectrally Modulated Ripple Test (SMRT); and music perception was evaluated using the Mini Profile of Music Perception Skills (mini-PROMS) and Melodic Contour Identification (MCI) tests. A significant difference was obtained with better scores in TURMatrix tests performed in noise and quiet with the P2. SMRT scores was significantly correlated with TURMatrix in quiet and noise, and miniPROMS sound perception results. While better scores were obtained with P2 in miniPROMS total score and MCI, a significant difference was found only for MCI. Equalization of loudness across CI electrodes improves perceptual acuity, according to the findings of the present study. Additionally, the correlation between music perception, speech perception, and spectral-temporal resolution was unveiled.