To investigate the cognitive and neural correlates of discourse impairment in corticobasal syndrome (CBS).
Difficulty communicating is a frequent clinical manifestation in patients with CBS. However, the mechanisms underlying this disabling problem are not well understood.
Twenty patients with CBS and 8 healthy seniors narrated a picture story. Narratives were analyzed for maintenance of the narrative theme, identification of the overall point of the story (global connectedness), and connectedness between consecutive events (local connectedness). Discourse measures were correlated with performance on cognitive tasks and with cortical atrophy as determined by magnetic resonance imaging voxel-based morphometry.
Patients with CBS referred to the narrative theme significantly less frequently than controls. Global connectedness was intact in only 6 of 20 CBS patients (30%), but preserved in all controls. Local connectedness was significantly diminished in patients relative to controls. Discourse performance in CBS was related to tasks requiring higher-order integration of visual material, but not to basic visuospatial/visuoperceptual, language, or memory function. Discourse impairment was directly related to atrophy in the right parietal lobe and bilateral dorsolateral prefrontal cortex.
Our findings suggest that impaired information integration in CBS, related to parieto-frontal disease, interferes with patients' ability to narrate a coherent story.
*Department of Neurology, University of Pennsylvania School of Medicine
†The Department of Neurology, Drexel University College of Medicine
‡The Department of Neurology, Thomas Jefferson University School of Medicine, Philadelphia, PA
Supported by an American Academy of Neurology Foundation Clinical Research Training Fellowship grant, as well as by NIH grants NS44266, AG17586, AG15116, and NS53488.
Reprints: Rachel G. Gross, MD, Department of Neurology, 3 West Gates Building, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104-4283 (e-mail: firstname.lastname@example.org).
Received for publication September 22, 2009
accepted October 11, 2009