A standardised test to evaluate audio-visual speech intelligibility in French.

Objective: Lipreading, which plays a major role in the communication of the hearing impaired, lacked a French standardised tool. Our aim was to create and validate an audio-visual (AV) version of the French Matrix Sentence Test (FrMST). Design: Video recordings were created by dubbing the existing audio files. Sample: Thirty-five young, normal-hearing participants were tested in auditory and visual modalities alone (Ao, Vo) and in AV conditions, in quiet, noise, and open and closed-set response formats. Results: Lipreading ability (Vo) ranged from 1 % to 77%-word comprehension. The absolute AV benefit was 9.25 dB SPL in quiet and 4.6 dB SNR in noise. The response format did not influence the results in the AV noise condition, except during the training phase. Lipreading ability and AV benefit were significantly correlated. Conclusions: The French video material achieved similar AV benefits as those described in the literature for AV MST in other languages. For clinical purposes, we suggest targeting SRT80 to avoid ceiling effects, and performing two training lists in the AV condition in noise, followed by one AV list in noise, one Ao list in noise and one Vo list, in a randomised order, in open or close set-format.

Vehicle noise: comparison of loudness ratings in the field and the laboratory.

Objective: Distorted loudness perception is one of the main complaints of hearing aid users. Measuring loudness perception in the clinic as experienced in everyday listening situations is important for loudness-based hearing aid fitting. Little research has been done comparing loudness perception in the field and in the laboratory.Design: Participants rated the loudness in the field and in the laboratory of 36 driving actions. The field measurements were recorded with a 360° camera and a tetrahedral microphone. The recorded stimuli, which are openly accessible, were presented in three conditions in the laboratory: 360° video recordings with a head-mounted display, video recordings with a desktop monitor and audio-only.Study samples: Thirteen normal-hearing participants and 18 hearing-impaired participants with hearing aids.Results: The driving actions were rated as louder in the laboratory than in the field for the condition with a desktop monitor and for the audio-only condition. The less realistic a laboratory condition was, the more likely it was for a participant to rate a driving action as louder. The field-laboratory loudness differences were bigger for louder sounds.Conclusion: The results of this experiment indicate the importance of increasing realism and immersion when measuring loudness in the clinic.

Development and evaluation of video recordings for the OLSA matrix sentence test.

OBJECTIVE: The aim was to create and validate an audiovisual version of the German matrix sentence test (MST), which uses the existing audio-only speech material. DESIGN: Video recordings were recorded and dubbed with the audio of the existing German MST. The current study evaluates the MST in conditions including audio and visual modalities, speech in quiet and noise, and open and closed-set response formats. SAMPLE: One female talker recorded repetitions of the German MST sentences. Twenty-eight young normal-hearing participants completed the evaluation study. RESULTS: The audiovisual benefit in quiet was 7.0 dB in sound pressure level (SPL). In noise, the audiovisual benefit was 4.9 dB in signal-to-noise ratio (SNR). Speechreading scores ranged from 0% to 84% speech reception in visual-only sentences (mean = 50%). Audiovisual speech reception thresholds (SRTs) had a larger standard deviation than audio-only SRTs. Audiovisual SRTs improved successively with increasing number of lists performed. The final video recordings are openly available. CONCLUSIONS: The video material achieved similar results as the literature in terms of gross speech intelligibility, despite the inherent asynchronies of dubbing. Due to ceiling effects, adaptive procedures targeting 80% intelligibility should be used. At least one or two training lists should be performed.

Movement and Gaze Behavior in Virtual Audiovisual Listening Environments Resembling Everyday Life.

Recent achievements in hearing aid development, such as visually guided hearing aids, make it increasingly important to study movement behavior in everyday situations in order to develop test methods and evaluate hearing aid performance. In this work, audiovisual virtual environments (VEs) were designed for communication conditions in a living room, a lecture hall, a cafeteria, a train station, and a street environment. Movement behavior (head movement, gaze direction, and torso rotation) and electroencephalography signals were measured in these VEs in the laboratory for 22 younger normal-hearing participants and 19 older normal-hearing participants. These data establish a reference for future studies that will investigate the movement behavior of hearing-impaired listeners and hearing aid users for comparison. Questionnaires were used to evaluate the subjective experience in the VEs. A test-retest comparison showed that the measured movement behavior is reproducible and that the measures of movement behavior used in this study are reliable. Moreover, evaluation of the questionnaires indicated that the VEs are sufficiently realistic. The participants rated the experienced acoustic realism of the VEs positively, and although the rating of the experienced visual realism was lower, the participants felt to some extent present and involved in the VEs. Analysis of the movement data showed that movement behavior depends on the VE and the age of the subject and is predictable in multitalker conversations and for moving distractors. The VEs and a database of the collected data are publicly available.