Word-retrieval in two cases of progressive supranuclear palsy

In this paper, we describe the detailed neuropsychological investigation of two cases of progressive supranuclear palsy (PSP) and demonstrate word-finding difficulties associated with pervasive problems in word-retrieval. The pattern of deficits resembles that seen in Parkinson's Disease (PD) but is more severe, even in very mild PSP, and appears less amenable to cue facilitation. Performance on a variety of word-production tasks is compared, and experimental controls for motor effects on performance are included. The role of stimulus cues in speeded word-finding is addressed experimentally, as are central executive influences on task performance. This combines with functional brain-scan data from single photon emission computed tomography (SPECT) which shows reduced frontal perfusion in one of the two cases.