This study examines the asynchrony detection ability between auditory and vibrotactile stimuli to improve the "VIBES" singing timing support system for Deaf and Hard-of-Hearing (DHH) individuals. We conducted synchrony judgment tasks with 20 DHH participants using a single device to present auditory and vibrotactile stimuli. We tested two conditions: a regular rhythm (RR) condition with contextual beats (120 beats per minute) surrounding the target stimulus and a no-rhythm (NR) condition where we presented only the target stimulus. Our results showed a significant negative shift in the point of subjective simultaneity (PSS: the timing at which two different sensory stimuli are perceived as co-occurring) under the NR condition (-15 [ms]), indicating that presenting vibrotactile stimuli before auditory stimuli facilitates simultaneity perception. We observed more expansive temporal binding windows (TBW: the period during which stimuli from different senses are integrated and perceived as a single event) when auditory stimuli preceded vibrotactile stimuli. This suggests that unintended vibrotactile interference from auditory stimuli occurs when using a single device. We also noted individual differences in asymmetry between the TBW of RR and the NR conditions. These findings suggest DHH participants may detect asynchrony based on comparison with surrounding stimuli rather than direct comparison of stimulus pairs, highlighting the importance of accurate timing estimation for adequate singing support.

With the advancement of hearing aids and cochlear implants, auditory perception among the Deaf and Hard-of-Hearing (D/HoH) people has improved, including the recognition of environmental and instrumental sounds. However, even with these improvements, it remains difficult for many deaf individuals to perceive emergency vehicle sirens. This study proposes more perceivable siren patterns by modifying pitch and tempo. Through awareness surveys and listening experiments with D/HoH individuals, we examined the perceived urgency and audibility of modified sirens. The results suggest that increasing the tempo improves both recognizability and perceived urgency, while higher octave shifts tend to be rated as noisy or annoying.

Abstract Access to music for people who are Deaf/Hard of Hearing (D/HoH) includes the instrumental portion and the lyrics. While closed captioning can provide the lyrics in text format, it does not necessarily provide accurate timing of the lyrics with the instrumental portion. This study aims to clarify how vibrotactile stimuli affect understanding the onset timing of song lyrics for D/HoH people. To achieve this goal, we developed a system called VIBES: VIBrotactile Engagement for Songs that simultaneously provides music and vibration playback as an iPhone app. Unlike other vibrotactile systems for music, which focus primarily on the percussion/beat or frequencies of the instrumental portions, VIBES presents vibrations for the timing of vocal utterances, syllable by syllable. We conducted a study with 10 participants to determine the system’s effectiveness by comparing the understanding of lyric timing with vibration and sound only. Statistically, one of the four songs in the experiment showed significant differences, where understanding lyric timing with vibration is better than in sound-only conditions. Two songs revealed the opposite results, and the other showed no differences between the two conditions. Although these results were unexpected, we obtained several findings to make the next version of VIBES, such as the frequency of vibrations.

Some deaf and hard-of-hearing (DHH) individuals like to “listen to” music. For them to access a wider range of music, both the preference for and the audibility of music are important. As a starting point for understanding music accessibility, we investigated the audibility and preference for 19 musical instruments using five pitches totaling 95 timbres. To examine how people listen to music daily, owing to the difficulty of having participants come to the laboratory due to the spread of COVID-19, we conducted the experiment online. Participants listened to short clips of 95 sounds and subjectively answered questions on their audibility and preferences. An analysis of their subjective answers revealed the audibility and preference differences among instruments, specifically that the recorder lacks the same audibility and preference as some of the other instruments at certain pitches. However, there was little correlation between audibility and timbre preferences. The study findings will be used in music classes in which DHH students participate and indicate that timbre audibility is necessary for building music recommendation systems for DHH individuals. We also discuss the limitations and possibilities of online experiments using sound. Music, timbre, deaf and hard of hearing, audibility, preference, accessibility

In previous studies, we conducted several experiments, including identification tests for young and elderly listeners using /shi/–/chi/ (CV) and /ishi/–/ichi/ (VCV) continua. For the CV stimuli, confusion of /shi/ as /chi/ increased when the frication had a long rise time, and /chi/ was confused with /shi/ when the frication had a short rise time. This was true for the group with the following auditory property degradation: 1) elevation of absolute threshold, 2) presence of loudness recruitment, and 3) deficit of auditory temporal resolution. When auditory property degradation was observed, the weighting of acoustic cues shifted to frication duration rather than the gradient of the amplitude of frication. The latter was calculated by dividing frication amplitude by rise time. In the VCV stimuli, confusion of /ichi/ as /ishi/ occurred for a long silent interval between the first V and C with auditory property degradation, and the weighting of acoustic cues shifted from the silent interval to frication duration. In the present study, we unified these findings into a single framework and found that degradation of auditory properties causes listeners to prefer duration of frication as a cue for identifying fricatives and affricates. Index Terms: elderly listeners, hearing impairments, aging, weighting shift of acoustic cues, trading relations, speech perception, fricatives/affricates

In the above titled paper (ibid., vol. 18, no. 7, pp. 1775-1780, Sep. 2010), several IPA fonts were displayed incorrectly. The correct fonts are presented here.

Reverberation is a large problem for speech communication and it is known that strong reverberation affects speech intelligibility. This is especially true for people with hearing impairments and/or elderly people. Several approaches have been proposed and discussed to improve speech intelligibility degraded by reverberation. Steady-state suppression is one such approach, in which speech signals are processed before being radiated through the loudspeakers of a public address system to reduce overlap masking, which is one of the major causes of degradation in speech intelligibility. We investigated whether the steady-state suppression technique improves the intelligibility of speech in reverberant environments for elderly listeners. In both simulated and actual reverberant environments, elderly listeners performed worse than younger listeners. The performance in an actual hall was better than with simulated reverberation, and this was consistent with the results for younger listeners. Although the normal hearing group performed better than the presbycusis group, the steady-state suppression technique improved the intelligibility of speech for elderly listeners as was observed for younger listeners in both simulated and actual reverberant environments.

In a large auditorium, perceiving speech may become difficult. One reason that reverberation degrades speech intelligibility is the effect of overlap-masking (Bolt and MacDonald, 1949; Nabelek and Robinette, 1978). Reverberation is a more critical issue for elderly people to perceive speech than it is for young people (Fitzgibbons and Gordon-Salant, 1999). Arai et al. suppressed steady-state portions of speech which have more energy but are less crucial for speech perception, and confirmed promising results for improving speech intelligibility (Arai et al., 2001, 2002). Hodoshima et al. conducted perceptual tests to confirm the effectiveness of steady-state suppression with several reverberation conditions, and obtained significant improvements with reverberation times of 0.7-1.3 s. In this study, we conducted an experiment for evaluating steady-state suppression with fifty elderly people and found that there were significant improvements. Also, steady-state suppression yielded better improvements in speech intelligibility for elderly people than it did for young people.