Broca失語とBroca領域失語：異なる失語症タイプを呈した左前頭葉出血の2症例

Different Types of Aphasia Caused by Cerebral Hemorrhage in the Left Frontal Lobe: Broca's Aphasia and Broca Area's Aphasia

Ⅰ．はじめに

　一般に左前頭葉損傷では，運動性失語に代表される非流暢型の失語が出現するとされてきた^2,17,20)．すなわち，アナルトリー（失構音）と喚語困難を要件とするBroca失語や，自発言語の障害に比して復唱の保たれる超皮質性運動失語などがその代表的なタイプである．これに対して，近年，左前頭葉損傷で流暢型の失語症が出現することが知られるようになった^{3,6,7,11,14,19)}．しかし，そのほとんどは脳梗塞の症例^3,7,11,14)であり，出血例の報告⁶⁾はほとんどない．

　今回われわれは，前頭葉弁蓋部を中心に，ほぼ同量の出血性病変を認めたにもかかわらず，異なる言語症状と臨床経過を示した2症例を経験したので，その症状の差異と血腫の進展方向について検討し報告する．

　We reported two cases of aphasia that exhibited different characteristics of aphasia following cerebral hemorrhage in the left frontal lobe involving the Broca's area.

　Case 1 is a 74-year-old right-handed woman. She was hospitalized with speech disturbance. Spontanoues speech was fluent and articulation was normal, but she showed verbal paraphasia and speech perseveration. She demonstrated a preserved ability to repeat short sentences and was able to read words aloud. This type of aphasia is called “Broca area's aphasia”. MRI and CT showed hematoma involving the left inferior frontal lobe, operculum and insula cortex. Single-photon emission computed tomography (SPECT) showed low perfusion in the frontal lobe without involvement of the postcentral gyrus.

　Case 2 is a 76-year-old right-handed man. He was also hospitalized with speech disturbance. Spontanoues speech was non-fluent and articulation was poor. He sometimes showed phonemic paraphasia with anarthria, but he demonstrated a preserved ability to repeat short sentences. He was able to read words aloud in a manner comparatively similar to. This type of aphasia is called “Broca's aphasia”. MRI and CT showed hematoma involving the left inferior frontal lobe, operculum and precentral cortex. SPECT revealed low perfusion in the frontal lobe extending to the postcentral gyrus. We supposed that the different characteristics of aphasia in those cases were due to extended lesion in the frontal lobe.