Brain Advance Access published online on March 24, 2008
Brain, doi:10.1093/brain/awn047
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Oculomotor function in frontotemporal lobar degeneration, related disorders and Alzheimer's disease
1Memory and Aging Center, Department of Neurology, 2Keck Center for Integrative Neuroscience, Department of Physiology, 3Department of Epidemiology and Biostatistics and 4Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
Correspondence to:
Adam L. Boxer, MD, PhD, Memory and Aging Center, Department of Neurology, University of California, San Francisco, Box 1207, San Francisco, CA 94143-1207, USA E-mail: aboxer{at}memory.ucsf.edu
Frontotemporal lobar degeneration (FTLD) often overlaps clinically with corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP), both of which have prominent eye movement abnormalities. To investigate the ability of oculomotor performance to differentiate between FTLD, Alzheimer's disease, CBS and PSP, saccades and smooth pursuit were measured in three FTLD subtypes, including 24 individuals with frontotemporal dementia (FTD), 19 with semantic dementia (SD) and six with progressive non-fluent aphasia (PA), as compared to 28 individuals with Alzheimer's disease, 15 with CBS, 10 with PSP and 27 control subjects. Different combinations of oculomotor abnormalities were identified in all clinical syndromes except for SD, which had oculomotor performance that was indistinguishable from age-matched controls. Only PSP patients displayed abnormalities in saccade velocity, whereas abnormalities in saccade gain were observed in PSP > CBS > Alzheimer's disease subjects. All patient groups except those with SD were impaired on the anti-saccade task, however only the FTLD subjects and not Alzheimer's disease, CBS or PSP groups, were able to spontaneously self-correct anti-saccade errors as well as controls. Receiver operating characteristic statistics demonstrated that oculomotor findings were superior to neuropsychological tests in differentiating PSP from other disorders, and comparable to neuropsychological tests in differentiating the other patient groups. These data suggest that oculomotor assessment may aid in the diagnosis of FTLD and related disorders.
Key Words: oculomotor; frontotemporal lobar degeneration; corticobasal syndrome; progressive supranuclear palsy; Alzheimer's disease
Abbreviations: CBD, corticobasal degeneration; CBS, corticobasal syndrome; CDR, clinical dementia rating; FTLD, frontotemporal lobar degeneration; FTD, frontotemporal dementia; PA, progressive non-fluent apahasia; PSP, progressive supranuclear palsy; ROC, receiver operating characteristic; SD, semantic dementia; TIV, total intra-cranial volume; UPDRS, Unified Parkinson's Disease Rating Scale
Received October 4, 2007. Revised February 6, 2008. Accepted February 22, 2008.