Brain activation patterns in normal hearing adults: An fNIRS Study using an adapted clinical speech comprehension...

Area of Science:

• Neuroscience
• Auditory and Visual Speech Perception
• Brain Imaging Techniques

Background:

• Understanding speech processing is crucial for hearing impairment interventions.
• Functional near-infrared spectroscopy (fNIRS) is suitable for measuring brain activity during language tasks.
• Validated stimuli and behavioral measures are necessary for accurate fNIRS data interpretation.

Purpose of the Study:

• To investigate brain processing of auditory and visual speech in adults with normal hearing.
• To assess the applicability of a clinically inspired audiovisual speech-comprehension task.
• To establish a baseline for visual cue processing during lipreading.

Main Methods:

• Twenty-six adults with normal hearing underwent fNIRS to measure brain activation.
• Participants listened to sentences in quiet, noise, audiovisual, or visual-only (lipreading) conditions.
• Hearing tests, questionnaires, comprehension questions, and listening effort ratings were collected.

Main Results:

• Auditory speech activated temporal regions; visual speech activated the occipital area.
• Audiovisual speech activated both temporal and occipital regions.
• Increased prefrontal cortex activity was observed in noise conditions, correlating with higher listening effort.

Conclusions:

• The study demonstrated the utility of an audiovisual speech-comprehension task in participants with normal hearing.
• fNIRS effectively measured brain activation patterns during various speech modalities.
• Objective and behavioral data supported and complemented the fNIRS findings.