Speech Perception in MRI Scanner Noise by Persons With Aphasia

Abstract

To examine reductions in performance on auditory tasks by aphasic and neurologically intact individuals as a result of concomitant magnetic resonance imaging (MRI) scanner noise. Four tasks together forming a continuum of linguistic complexity were developed. They included complex-tone pitch discrimination, same-different discrimination of minimal pair syllables, lexical decision, and sentence plausibility. Each task was performed by persons with aphasia (PWA) and by controls. The stimuli were presented in silence and also in the noise recorded from within the bore of a 3 Tesla MRI scanner at 3 signal-to-noise (S/N) ratios. Across the 4 tasks, the PWA scored lower than the controls, and performance fell as a function of decreased S/N. However, the rate at which performance fell was not different across the 2 listener groups in any task. Depending on the relative levels of the signals and noise, the intense noise accompanying MRI scanning has the potential to severely disrupt performance. However, PWA are no more susceptible to the disruptive influence of this noise than are unimpaired individuals usually employed as controls. Thus, functional MRI data from aphasic and control individuals may be interpreted without complications associated with large interactions between scanner noise and performance reduction.