Specific temporoparietal gyral atrophy reflects the pattern of language dissolution in Alzheimer's disease

The aim of this study was to determine the topography and degree of atrophy in speech and language-associated cortical gyri in Alzheimer's disease. Th e post-mortem brains of 10 patients with pathologically confirmed Alzheimer 's disease and 21 neurological and neuropathological controls were sectione d in serial 3 mm coronal slices and grey and white matter volumes were dete rmined for specific cortical gyri, All Alzheimer's disease patients had pro spectively documented impairments in verbal and semantic memory with concom itant global decline, The cortical regions of interest included the planum temporale, Heschl's gyri, the anterior superior temporal gyri, the middle a nd inferior temporal gyri, area 37 at the inferior temporoparietal junction , areas 40 and 39 (supramarginal and angular gyri) and Broca's frontal regi ons. Although most patients had end-stage disease, the language-associated cortical regions were affected to different degrees, with some regions free of atrophy, These included Broca's regions in the frontal lobe and Heschl' s gyri on the superior surface of the temporal lobe, In contrast, the infer ior temporal and temporoparietal gyri (area 37) were severely reduced in vo lume. The phonological processing regions in the superior temporal gyri (th e planum temporale) were also atrophic in all Alzheimer's disease patients while the anterior superior temporal gyri were only atrophic in female pati ents. Such atrophy may underlie the more severe language impairments previo usly described in females with Alzheimer's disease. The present study is th e first to analyse the volumes of language-associated gyri in post-mortem p atients with confirmed Alzheimer's disease, The results show that atrophy i s not global but site-specific. Atrophied gyri appear to reflect a specific network of language and semantic memory dissolution seen in the clinical f eatures of patients with Alzheimer's disease. Females showed greater atroph y than males in the anterior superior temporal gyri.