The FRONTAL-PEG study focuses on taste perception in frontotemporal lobar degeneration (FTLD). This neurodegenerative disease, characterised by progressive loss of nerve cells, is the second leading cause of dementia after Alzheimer's disease. Patients with FTLD often experience olfactory disorders (= sense of smell) and eating disorders: increased appetite, increased food intake and excessive consumption of sugary foods and snacking. This often leads to excessive weight gain. These eating disorders are still poorly understood at present. In this context, we hypothesise that an alteration in the gustatory pathway - i.e. the way in which the brain perceives taste - could contribute to the eating disorders frequently observed in frontotemporal dementia (FTD), particularly in the marked attraction to sweet foods. We therefore wish to objectively evaluate the taste response to a sweet solution (sucrose) in patients with FTLD, using taste evoked potentials (TEPs). Taste evoked potentials are a reliable and reproducible technique for assessing brain activity in response to taste stimulation. One of their advantages is that they are non-invasive. This study will document, for the first time in this disease, the characteristics of cortical (brain) processing of taste information. The FRONTAL-PEG study is an interventional, regional, single-centre study conducted at the Dijon University Hospital, in collaboration with the CMRR (Memory, Resources and Research Centre) and the CSGA (Centre for Taste and Food Sciences). All investigations are carried out at the CSGA (building adjacent to the Dijon University Hospital), with the exception of blood tests, which are carried out at the Dijon University Hospital. The total duration of participation in the study is one morning. No follow-up is planned at the end of the study.