[Symptoms of frontotemporal dementia].

Frontotemporal dementia (FTD)-a common clinical manifestation of frontotemporal lobar degeneration (FTLD)--is characterized by alterations in personality and social conduct. Its symptoms include inertia, loss of volition, social disinhibition, and distractibility, with relative preservation of memory and visuospatial function. We present the typical case of patient with typical clinical symptoms including "going my way" behavior, inactivity, lack of awareness of illness, stereotypic behavior, perseveration, and environmental dependency syndrome. These clinical symptoms can be interpreted on the basis of extent of damage to the frontal lobes and the interaction between the frontal lobes and other neural systems such as the posterior association cortices, basal ganglia or limbic systems. We also address several complex clinical issues, including the relationship between clinical manifestations and pathological findings, underestimation of FTD in patients with amyotrophic lateral sclerosis (ALS) and/or motor neuron disease (MND), and impairment in a single cognitive domain such as isolated agraphia in ALS/MND and FTD. To address these problems, it is essential to observe the clinical symptoms in patients with FTD and ALS/MND in detail and to compare clinical characteristics with pathological findings. It is also critical to develop clinical tests that minimize the impact of speech and motor dysfunction on performance, particularly on the basis of a longitudinal analysis.