Real‐time noise cancellation for speech acquired in interactive functional magnetic resonance imaging studies

Abstract

Purpose: To present online scanner noise cancellation for speech acquired in functional magnetic resonance imaging (fMRI) studies. Materials and Methods:An online active noise cancellation method for speech acquired in fMRI studies was developed. The approach consists of two automated steps: 1) creation of an MR noise template in a short ''test'' fMRI scan; 2) application of the template for automatic recognition and subtraction of the MR noise from the acquired microphone signal during an fMRI study. The method was applied in an experimental paradigm where a subject and an investigator communicated in an interactive verbal generation task during fMRI.Results: By applying online active noise cancellation, the quality of the subject's speech was substantially improved. The present approach was found to be flexible, reliable, and easy to implement, providing a method for fMRI studies that investigate the neural correlates of interactive speech communication. Conclusion:Using online noise cancellation it is possible to improve the quality of acquired speech in fMRI. This approach may be recommended for interactive fMRI studies.

Morphometric Differences of Vocal Tract Articulators in Different Loudness Conditions in Singing

“…Since noise reduction was performed by means of dedicated software the noise cancellation process may also have changed the voice signal. Furthermore, since there are other approaches for noise cancellation [ 53 , 54 ] it cannot be excluded that other systems would show differences concerning the absolute values of the SPL. However, the same filter conditions were applied to all three of the tasks (pp, mf, and ff, respectively) and the error should only be of a systematic nature.…”

Prosody production networks are modulated by sensory cues and social context

“…The participants’ speech was recorded via an MRI compatible fiber-optic microphone attached to the head coil (prototype from Sennheiser electronic GmbH & Co KG, Wedemark-Wennebostel, Germany). Microphone recordings were filtered online in real time to minimize the scanner noise for the listener, using a template-based subtraction approach ( Zvyagintsev et al , 2010 ). This setup allowed the experimenter to listen to the participant’s speech and prosody in real time.…”

“…However, interactive prosodic communication is a major technical challenge in noisy high-field fMRI environment. An optical microphone and online digital signal processing (DSP) enabled bidirectional communication despite the scanner noise ( Zvyagintsev et al , 2010 ).…”