title: Partially overlapping sensorimotor networks underlie speech praxis and verbal short-term memory: evidence from apraxia of speech following acute stroke.
abstract: We tested the hypothesis that motor planning and programming of speech articulation and verbal short-term memory (vSTM) depend on partially overlapping networks of neural regions. We evaluated this proposal by testing 76 individuals with acute ischemic stroke for impairment in motor planning of speech articulation (apraxia of speech, AOS) and vSTM in the first day of stroke, before the opportunity for recovery or reorganization of structure-function relationships. We also evaluated areas of both infarct and low blood flow that might have contributed to AOS or impaired vSTM in each person. We found that AOS was associated with tissue dysfunction in motor-related areas (posterior primary motor cortex, pars opercularis; premotor cortex, insula) and sensory-related areas (primary somatosensory cortex, secondary somatosensory cortex, parietal operculum/auditory cortex); while impaired vSTM was associated with primarily motor-related areas (pars opercularis and pars triangularis, premotor cortex, and primary motor cortex). These results are consistent with the hypothesis, also supported by functional imaging data, that both speech praxis and vSTM rely on partially overlapping networks of brain regions.
authors.affiliation: Department of Cognitive Sciences, Center for Language Science, Center for Cognitive Neuroscience and Engineering, University of California Irvine, CA, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Hickok
authors.affiliation: Department of Speech and Hearing Science, Arizona State University Tempe, AZ, USA.
authors.forename: Corianne
authors.initials: C
authors.lastname: Rogalsky
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Baltimore, MD, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Baltimore, MD, USA.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Herskovits
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine Baltimore, MD, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Townsley
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Cognitive Science, Johns Hopkins University Baltimore, MD, USA.
authors.forename: Argye E
authors.initials: AE
authors.lastname: Hillis
keywords: aphasia; apraxia of speech; language; motor control; short term memory; speech production; stroke