Atrophy progression in semantic dementia with asymmetric temporal involvement: A tensor-based morphometry study

Abstract

We performed a longitudinal anatomical study to map the progression of gray matter atrophy in anatomically defined predominantly left (LTLV) and right (RTLV) temporal lobe variants of semantic dementia (SD). T1-weighted MRI scans were obtained at presentation and one-year followup from 13 LTLV, 6 RTLV, and 25 control subjects. Tensor-based morphometry (TBM) in SPM2 was applied to derive a voxel-wise estimation of regional tissue loss over time from the deformation field required to warp the follow-up scan to the presentation scan in each subject. When compared to controls, both LTLV and RTLV showed significant progression of gray matter atrophy not only within the temporal lobe most affected at presentation, but also in the controlateral temporal regions (p < 0.05 FWE corrected). In LTLV, significant progression of volume loss also involved the ventromedial frontal and the left anterior insular regions. These results identified the anatomic substrates of the previously reported clinical evolution of LTLV and RTLV into a unique 'merged' clinical syndrome characterized by semantic and behavioral deficits and bilateral temporal atrophy.

Progression of language decline and cortical atrophy in subtypes of primary progressive aphasia

“…17,18 Though the methodology was different, the results from the semantic subtype study, which showed a posterior spread of temporal atrophy and decline in word comprehension, were consistent with our findings. Other studies have examined neuropsychological decline in PPA but have not quantified changes in atrophy.…”

P2‐241: Focal Temporal Pole Atrophy and Network Degeneration in Semantic Variant Primary Progressive Aphasia

“…We further investigated the reliability of focal atrophy across individual patients and found that 100% of individuals in both svPPA samples had one of their maximally atrophic points in the same temporopolar region. Beyond the anterior temporal cortex, patients with svPPA exhibit less prominent neurodegeneration in distributed cortical and subcortical regions (Mummery et al, 2000;Rosen et al, 2002;Gorno-Tempini et al, 2004;Brambati et al, 2009;Rohrer et al, 2009). As predicted, the focal atrophy point identified in our cortical thickness analysis was interconnected with a network of brain regions in healthy adults that closely resembled the distributed cortical atrophy pattern of svPPA patients, replicating previous findings .…”

The anatomic correlate of prosopagnosia in semantic dementia

“…It is very likely, however, that atrophy in these subjects will eventually spread to involve the right temporal lobe, as has been suggested by a couple of longitudinal studies in semantic dementia. 39,40 An unexpected finding was the fact that the prosopagnosia subjects had a higher female to male ratio than the subjects without prosopagnosia. Given that we have a relatively small sample size this could have occurred by chance.…”