Age-Related Differences in Speech and Gray Matter Volume: The Modulating Role of Multilingualism

Area of Science:

• Neuroscience
• Linguistics
• Gerontology

Background:

• Speech abilities naturally decline with age, affecting fluency and complexity.
• Older adults exhibit reduced gray matter volume, but its link to speech changes is unclear.
• Multilingualism may influence age-related speech patterns differently based on language background.

Purpose of the Study:

• To investigate the relationship between age-related brain structure differences and multilingual speech.
• To examine how multilingual experience affects speech quality across different languages in aging adults.
• To identify specific brain regions involved in multilingual speech in older adults.

Main Methods:

• Calculated an integrated measure of speech quality.
• Compared speech performance in native (Cantonese) and non-native (Mandarin) languages.
• Correlated speech quality and brain gray matter volume with age and multilingual experience.

Main Results:

• Overall speech quality was lower in older adults compared to younger adults.
• Native language speech was superior to non-native, particularly in older individuals.
• Extensive multilingual use correlated with better speech quality in both native and non-native languages.
• Older adults had lower whole brain gray matter volume.
• The right middle temporal gyrus was critical for speech in both languages in older adults.
• Bilateral putamen sensitivity to multilingual experience was observed in older adults' speech.

Conclusions:

• Age significantly impacts speech and gray matter volume.
• Multilingualism can enhance speech performance in older adults.
• Specific brain regions, including the right middle temporal gyrus and bilateral putamen, are key to understanding age, multilingualism, and speech.