Sound source’s position is shifted towards the left or right, as well as the MAA is measured by asking the participant to answer no matter if the test sound is heard from the left or appropriate in the reference. Already in 1958, Mills [47] described that the MAA for any tone of 1 kHz or higher is about 1 degree at an azimuth of 0 degrees. The discrimination task is also easy for young children to measure the ultimate sensitivity with the localization technique [4]. For instance, Lovett et al. (2012) [48] reported that youngsters showed adult levels of efficiency from age three years for left ight discrimination, and from age 6 years for localization. Asp et al. (2016) [49] developed a corneal reflection eye-tracking strategy to record pupil positions toward spatially distributed continuous auditory and visual stimuli to assess horizontal sound localization accuracy from 6 months of age. They showed that the system gives an objective and quick assessment of horizontal sound localization accuracy. two.two.2. Stimulus Situations Pink noise, white noise, and broadband noise are normally utilized as the stimulus sound, as shown in Tables 1 and two. When used with wideband frequency, it is actually essential to Barnidipine Protocol confirm whether the stimulus sound is sufficiently reproduced within the device’s frequency variety. Yost et al. (2014) [50] described that the accuracy of sound source localization increases because the bandwidth of the stimulus sound increases, and that stimuli using a wide array of 1 octave or extra have the most effective sound source localization accuracy. The onset duration from the stimulus also impacts sound source localization [51]. Stimulus levels are typically employed at a degree of 65 dB SPL or 65 dB A, as shown in Tables 1 and two, which corresponds for the intensityAudiol. Res. 2021,level of conversation. When the stimulus presentation level becomes bigger, it exceeds the earplugged air conduction threshold or the actual patient’s threshold with CHL. In this case, each the bone-conducted sound, by means of bilaterally fitted BCDs, plus the suprathreshold air-conducted sound could be presented simultaneously towards the cochleae and interfere with the sound localization cues (Figure two). two.three. Participants You can find merits and demerits in sound localization experiments for employing, respectively, participants with normal hearing (bilateral simulated CHL) and individuals with bilateral CHL. 2.3.1. Normal-Hearing Participants with Simulated CHL Normal-hearing participants are employed to simulate bilateral CHL by blocking their ears with earplugs (and earmuffs) or earmolds. Normal-hearing participants with simulated CHL possess the positive aspects of normally created hearing, plus the BC thresholds of your left and correct ears under masking could be accurately measured. The participants thus is often assumed to become a homogeneous study group. Having said that, there’s a limit of sound insulation by earplugs and earmuffs, and also the audiogram of simulated CHL depends upon the sound insulation efficiency. For example, in an experiment to investigate the effect of simulated unilateral hearing loss on horizontal sound localization by Asp et al. (2018) [52], the degrees of hearing loss had been mild hearing loss (average threshold of 30 dB HL across 0.5, 1, 2, and four kHz) with an earplug, and moderate hearing loss (typical threshold of 43 dB HL across 0.5, 1, two, and four kHz) with an earplug and earmuff. Moreover, each audiogram configurations showed larger hearing loss inside the high frequencies than within the low frequencies. Compared with actual patients with CHL, these degrees.