Delayed auditory feedback simulates features of nonfluent primary progressive aphasia

Area of Science:

• Neurology
• Speech-Language Pathology
• Cognitive Neuroscience

Background:

• The underlying causes of nonfluent primary progressive aphasia (nfvPPA) are not fully understood.
• Altered auditory feedback (DAF) is known to affect speech production in healthy individuals.

Purpose of the Study:

• To investigate the effects of DAF on speech parameters in patients with nfvPPA and healthy controls.
• To explore DAF as a potential model for understanding nfvPPA pathophysiology.

Main Methods:

• Quantitative analysis of speech parameters in 15 nfvPPA patients and 17 healthy older adults.
• Speech recording under varying DAF latencies (0, 50, 200 ms) and pitch shifts.
• Comparison of speech rate and sound error frequency between groups and conditions.

Main Results:

• DAF significantly reduced speech rate and increased speech sound errors in healthy individuals, especially at 200 ms latency.
• A subset of healthy individuals under DAF exhibited speech slowing and errors comparable to the nfvPPA cohort.
• Findings indicate that distorted auditory feedback may contribute to nfvPPA symptoms.

Conclusions:

• nfvPPA's speech characteristics may stem from impaired auditory signal processing, simulated by DAF.
• DAF offers a potential pathophysiological model for posterior dorsal cortical language pathway dysfunction in nfvPPA.
• This research provides new insights into the neural mechanisms of speech production deficits in nfvPPA.