Specific cognitive deficits in mild frontal variant frontotemporal dementia

Eight patients with relatively mild frontal variant frontotemporal dementia (fvFTD) were compared with age- and IQ-matched control volunteers on tests of executive and mnemonic function. Tests of pattern and spatial recogniti on memory, spatial span, spatial working memory, planning, visual discrimin ation learning/attentional set-shifting and decision-making were employed. Patients with fvFTD were found to have deficits in the visual discriminatio n learning paradigm specific to the reversal stages. Furthermore, in the de cision-making paradigm, patients were found to show genuine risk-taking beh aviour with increased deliberation times rather than merely impulsive behav iour. It was especially notable that these patients demonstrated virtually no deficits in other tests that have also been shown to be sensitive to fro ntal lobe dysfunction, such as the spatial working memory and planning task s. These results are discussed in relation to the possible underlying neuro pathology, the anatomical connectivity and the hypothesized heterogeneous f unctions of areas of the prefrontal cortex. In particular, given the nature of the cognitive deficits demonstrated by these patients, we postulate tha t, relatively early in the course of the disease, the ventromedial (or orbi tofrontal) cortex is a major locus of dysfunction and that this may relate to the behavioural presentation of these patients clinically described in t he individual case histories.