行動型前頭側頭型認知症の症候学

Symptomatology of Behavioral Variant of Frontotemporal Dementia

前頭側頭葉変性症の中核的な臨床類型である行動型前頭側頭型認知症では，前頭葉の損傷に伴って脱抑制や意欲低下，共感性の欠如，常同行動，食行動の変化といった多彩な社会行動の変容が病初期から出現し，緩徐に進行する。疾患特異的なバイオマーカーは存在せず，画像診断や認知機能検査も補助的な位置付けであり，診断は行動症状の評価が基本となる。診断基準は有用であるが，精神疾患を含む他の病態との鑑別診断が困難な場合があり，過剰診断や過小診断に陥りやすいため，注意が必要である。

Abstract

In patients with the behavioral variant of frontotemporal dementia, the core clinical phenotype of frontotemporal lobar degeneration, various social behaviors such as disinhibition, apathy, lack of empathy, stereotypy, and changes in eating behavior occur from the onset of the disease, and progresses slowly with frontal lobe damage. Because there are no disease-specific biomarkers, the diagnosis of frontotemporal dementia is based on the evaluation of behavioral symptoms, with neuroimaging methods and cognitive tests as assisting methods. Although diagnostic criteria are useful, frontotemporal dementia may be difficult to differentiate from other conditions, including mental illnesses. We need to be careful to avoid overdiagnosis and underdiagnosis.