In the current study, temporal resolution, speech reception thresholds (SRT), and spatial masking release (SRM) under reverberation were measured for those with unilateral hearing loss (UHL), monaural normal hearing (MNH), and bilateral normal hearing (BNH). Results of gap detection using broadband noise showed that MNH had about 0.3 s longer response time, which means listening effort. As results of SRT, the group of UHL and MNH had upper SRTs than BNH, which means reverberation is one of the factors that interfere with speech perception for those with UHL. Comparing longstanding UHL (29.06 years; 1SD: 14.19) and MNH, results also suggested that there was a process of adaptation contributing improvement in release from masking of reverberation and SRM.

Cochlear synaptopathy, a synaptic dysfunction between inner hair cells and the auditory nerve, is one of the causes of "hidden hearing loss" which is referred to as difficulty in hearing in noisy environments even for people with normal audiometry. Although it is known that cochlear synaptopathy selectively damages auditory nerve fibers with a low spontaneous firing rate, no method has been established to evaluate the low spontaneous firing rate fibers in living humans. In this study, we measured wave I of the auditory brainstem response (ABR-1), which is known to reflect the activity of the auditory nerve, to establish an objective method for evaluating cochlear synaptopathy in humans. We used a paired-click stimulus to take advantage of the difference in adaptation characteristics between the low and high spontaneous firing rate fibers. The results showed that the intensity of ABR-1 to the second click of paired-click stimulus with a relatively short inter-click interval was greater in young than in middle-aged subjects and correlated with word intelligibility in noisy environments. Computer simulations of auditory nerve activity showed that the contribution of the low spontaneous firing rate fibers was greater for shorter inter-click interval conditions.

Advances in computational power and the software development environment provide interactive visualization and sonification tools applicable to speech science and technology education. This article introduces current representative examples and future trends referring to our tools under development. We also discuss practical scenarios in classes and laboratory lessons.

In this study, a method for visualizing speech sound for the purpose of speech training for deaf and hard-of-hearing students was investigated. The students recorded their own voices in a class on speech and acoustics and visualized their speech sounds. Audacity and Praat, the speech analysis software, were used for visualization. Time waveforms, spectrograms, pitch, and pressure levels were displayed. The students were able to describe the di!erence in pitch when compared to the author's voice but could not analyze the phoneme level. In the future, I will continue to study the acoustic features displayed and investigate a method to visualize them in real time.

Auditory psychology is a required subject in speech therapist training school. However, it seems that the subject is not very memorable for students. We held a seminar for Auditory psychology to solve the problem. This presentation is a seminar report.