title: Overt propositional speech in chronic nonfluent aphasia studied with the dynamic susceptibility contrast fMRI method.
abstract: This study examined activation levels in the left (L) supplementary motor area (SMA) and the right (R) SMA (separately), and activation in nine R perisylvian language homologues during overt, propositional speech in chronic nonfluent aphasia patients. Previous functional imaging studies with a variety of chronic aphasia patients have reported activation in these regions during different language tasks, however, overt propositional speech has not been examined. In the present research, four nonfluent aphasia patients were studied during overt elicited propositional speech at 4-9 years post-single L hemisphere stroke, which spared the SMA. The dynamic susceptibility contrast (DSC) method of functional MRI was used to calculate relative cerebral blood volume (relCBV) for cortical regions of interest (ROIs) during the first-pass bolus of gadolinium during two conditions: (1) pattern (silent viewing of checkerboard patterns) and (2) story (overt, elicited propositional speech describing sequential pictures, which formed a story). During the story condition, controls had significantly higher relCBV in L SMA than in R SMA; aphasics, however, had significantly higher relCBV in R SMA than in L SMA. During the pattern condition, no significant differences were observed between the L SMA and the R SMA for either controls or aphasics. In addition, aphasics had significantly higher relCBV in the R sensorimotor mouth during story than pattern. This R sensorimotor mouth relCBV was also significantly higher in aphasics than controls during story, and the two groups did not differ during pattern. The overall mean relCBV for the nine R perisylvian ROIs was significantly higher for aphasics than controls during both story and pattern. These results suggest that poor modulation, including possible over-activation of R sensorimotor mouth and other R perisylvian language homologues may underlie in part, the hesitant, poorly articulated, agrammatic speech associated with nonfluent aphasia.
authors.affiliation: Harold Goodglass Aphasia Research Center and Department of Neurology, Boston University School of Medicine and VA Boston Healthcare System, Boston, MA 02130, USA. mnaeser@bu.edu
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Naeser
authors.forename: Paula I
authors.initials: PI
authors.lastname: Martin
authors.forename: Errol H
authors.initials: EH
authors.lastname: Baker
authors.forename: Steven M
authors.initials: SM
authors.lastname: Hodge
authors.forename: Susan E
authors.initials: SE
authors.lastname: Sczerzenie
authors.forename: Marjorie
authors.initials: M
authors.lastname: Nicholas
authors.forename: Carole L
authors.initials: CL
authors.lastname: Palumbo
authors.forename: Harold
authors.initials: H
authors.lastname: Goodglass
authors.forename: Arthur
authors.initials: A
authors.lastname: Wingfield
authors.forename: Ranji
authors.initials: R
authors.lastname: Samaraweera
authors.forename: Gordon
authors.initials: G
authors.lastname: Harris
authors.forename: Abigail
authors.initials: A
authors.lastname: Baird
authors.forename: Perry
authors.initials: P
authors.lastname: Renshaw
authors.forename: Deborah
authors.initials: D
authors.lastname: Yurgelun-Todd
mesh_terms: D000328:Adult; D001039:Aphasia, Broca / Q000209:etiology / Q000473:pathology* / Q000523:psychology*; D002908:Chronic Disease; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology; D010100:Oxygen / Q000097:blood; D013003:Somatosensory Cortex / Q000473:pathology; D013060:Speech; D020521:Stroke / Q000150:complications; D014705:Verbal Behavior / Q000502:physiology*
chemical_list: D010100:Oxygen