Authors:

ADLAM, A.L.R., ROGERS, T., GRAHAM, K., PATTERSON, K. & HODGES, J.R.

Reference:

Year of publication:

2005

CBU number:

6064

Abstract:

We previously reported that patients with semantic dementia (SD) have deficits in both verbal and non-verbal semantic memory (Bozeat et al., 2000; 2002; Hodges et al., 2000). Some authors suggest that this profile is different to that seen in primary progressive aphasia (PPA) and that the pathology in SD encompasses both left-hemisphere language and bilateral inferotemporal-fusiform networks for faces and objects (e.g., Mesulam et al., 2003). We present data on 7 patients who presented with a clinical profile consistent with PPA. All patients showed bilateral pathology in the anterior temporal lobe: 3 had predominantly right hemisphere involvement, while the others had predominantly left hemisphere disease, as revealed on MRI. They were tested on a variety of verbal and non-verbal semantic memory measures, including colour selection, object use and action knowledge, and matching environmental sounds to pictures. All 7 patients showed both verbal and non-verbal deficits relative to matched controls and the magnitude of these impairments increased with severity of the disease as judged by degree of anomia and extent of brain atrophy. Together these findings support our view that PPA and SD are synonymous, and that these patients exhibit deficits on both verbal and visual-based tasks with a predictable pattern which reflects progressive breakdown of an amodal integrative semantic memory system.