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

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.

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.

One female talker recorded repetitions of the German MST sentences. Twenty-eight young normal-hearing participants completed the evaluation study.

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.

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.