Sensorimotor impairment of speech auditory feedback processing in aphasia

Abstract

We investigated the brain network involved in speech sensorimotor processing by studying patients with post-stroke aphasia using an altered auditory feedback (AAF) paradigm. We combined lesion-symptom-mapping analysis and behavioral testing to examine the pervasiveness of speech sensorimotor deficits and their relationship with cortical damage. Sixteen participants with aphasia and sixteen neurologically intact individuals completed a speech task under AAF. The task involved producing speech vowel sounds under the real-time pitch-shifted auditory feedback alteration. This task provided an objective measure for each individual's ability to compensate for mismatch (error) in speech auditory feedback. Results indicated that compensatory speech responses to AAF were significantly diminished in participants with aphasia compared with control. We observed that within the aphasic group, subjects with lower scores on the speech repetition task exhibited greater degree of diminished responses. Lesion-symptom-mapping analysis revealed that the onset phase (50-150 ms) of diminished AAF responses were predicted by damage to auditory cortical regions within the superior and middle temporal gyrus, whereas the rising phase (150-250 ms) and the peak (250-350 ms) of diminished AAF responses were predicted with damage to the inferior frontal gyrus and supramarginal gyrus areas, respectively. These findings suggest that damage to the auditory, motor, and auditory-motor integration networks are associated with impaired sensorimotor function for speech error processing. We suggest that a sensorimotor integration network, as revealed by brain regions related to temporal specific components of AAF responses, is related to speech processing and specific aspects of speech impairment, notably repetition deficits, in individuals with aphasia.

Mental operations in rhythm: motor-to-sensory transformation mediates imagined singing

“…The responses in these frontal cortices were also consistent with findings in speech imagery, reflecting the function of motor simulation [25]. In the parietal region, the observation of IPS and TPJ, an area closed to SMG, PO and Angular Gyrus (AG), has also been suggested for sensorimotor integration and goal-directed prediction-based speech feedback control [55][56][57][58]. The activation of similar parietal areas of TPJ, SMG, PO, and adjacent IPS was also observed during speech imagery, suggesting the possible functions for estimating somatosensory consequences of actions [22,25].…”

Mental operations in rhythm: Motor-to-sensory transformation mediates imagined singing

“…parietal region, the observation of the IPS and TPJ-an area closed to the supramarginal gyrus (SMG), parietal operculum (PO), and angular gyrus (AG)-has also been suggested for sensorimotor integration and goal-directed prediction-based speech feedback control [55][56][57][58]. The activation of similar parietal areas of the TPJ, SMG, PO, and adjacent IPS was also observed during speech imagery, suggesting the possible functions for estimating somatosensory consequences of actions [22,25].…”

Noninvasive neurostimulation of left ventral motor cortex enhances sensorimotor adaptation in speech production

“…The results of this study further our knowledge of the cortical mechanisms supporting the speech motor system's ability to adapt in response to altered sensory feedback. Additionally, these findings have implications for understanding how to effectively deploy tDCS as both a research instrument and a therapeutic technique in treatment of speech motor control issues involving abnormal feedback-based adaptation, such as stuttering (Cai et al, 2012;Daliri et al, 2017;Chesters et al, 2018), aphasia (Behroozmand et al, 2018), and Parkinson's disease (Abur et al 2018). Participants' F1 productions were averaged within blocks of three trials for display; all statistical tests were performed on single trial data.…”