Journal of the International Neuropsychological Society

Research Articles

Coordinated and circumlocutory semantic naming errors are related to anterolateral temporal lobes in mild AD, amnestic mild cognitive impairment, and normal aging

MARCIO LUIZ FIGUEREDO BALTHAZARa1a2 c1, CLARISSA LIN YASUDAa2, FABRÍCIO RAMOS SILVESTRE PEREIRAa2, FELIPE PAULO GUAZZI BERGOa2, FERNANDO CENDESa2 and BENITO PEREIRA DAMASCENOa1

a1 Neuropsychology and Neurolinguistics Unit, Department of Neurology, Medical School, University of Campinas (UNICAMP), Brazil

a2 Neuroimaging Laboratory, Department of Neurology, Medical School, University of Campinas (UNICAMP), Brazil

Abstract

Naming difficulties are characteristic of Alzheimer’s disease (AD) and, to a lesser extent, of amnestic mild cognitive impairment (aMCI) patients. The association of naming impairment with anterior temporal lobe (ATL) atrophy in Semantic Dementia (SD) could be a tip of the iceberg effect, in which case the atrophy is a marker of more generalized temporal lobe pathology. Alternatively, it could reflect the existence of a functional gradient within the temporal lobes, wherein more anterior regions provide the basis for greater specificity of representation. We tested these two hypotheses in a study of 15 subjects with mild AD, 17 with aMCI, and 16 aged control subjects and showed that coordinate and circumlocutory semantic error production on the Boston Naming Test was weakly correlated with ATL gray matter density, as determined by voxel-based morphometry. Additionally, we investigated whether these errors were benefited by phonemic cues, and similarly to SD, our AD patients had small improvement. Because there is minimal gradient of temporal lobe atrophy in AD or MCI, and, therefore, no basis for a tip of the iceberg effect, these findings support the theory of a modest functional gradient in the temporal lobes, with the ATLs being involved in the naming of more specific objects. (JINS, 2010, 16, 1099–1107.)

(Received October 15 2009)

(Reviewed July 29 2010)

(Accepted July 31 2010)

Correspondence:

c1 Correspondence and reprint requests to: Marcio L.F. Balthazar, Department of Neurology, Medical School, University of Campinas (UNICAMP), Postcode: 13083-970, Campinas-SP, Brazil. Email: mbalth@gmail.com