Multisensory simultaneity-judgment training and speech comprehension in patients with schizophrenia

Multisensory integration allows the brain to align auditory and visual signals in time, a process critical for accurate perception. This process has been shown to be abnormal in schizophrenia (SZ); patients show a wider temporal binding window (TBW), perceiving asynchronous inputs as simultaneous over longer intervals. Such deficits have been linked to hallucinations, disorganized symptoms, and impaired speech comprehension in SZ. While prior studies suggest that audiovisual simultaneity-judgment training (SJT) can recalibrate temporal perception in healthy adults, its efficacy in SZ has not yet been demonstrated. This study tested a feedback-based audiovisual SJT in 30 clinically stable SZs. Across three sessions, we assessed changes in simultaneity judgment, multisensory illusion susceptibility (sound-induced flash illusion; SIFI), and speech-in-noise comprehension (word recognition task). Mixed-effects models showed that the SJT significantly reduced the range of audiovisual pairs judged synchronous, consistent with a narrower TBW that persisted for two weeks. This change in simultaneity judgments was also associated with better word recognition in noisy conditions, both with audiovisual and auditory-only input. No training effects emerged for SIFI. These findings provide initial evidence that SJT may improve audiovisual temporal processing in SZ and enhance speech comprehension in noisy environment.