大脳皮質機能マッピング法による脳腫瘍患者の神経心理学的検討

Neuropsychological Findings of Functional Cortical Mapping in Patients with Brain Tumors

　切除の対象となる部位が言語領野ないしその近傍と考えられた脳腫瘍3例について術前に硬膜下電極の電気刺激による大脳皮質機能のマッピングを行い，神経心理学的検査を通して言語機能局在について以下の知見が得られた。1）ブローカ領野のみの電気刺激では語健忘や呼称の誤りが生じるのみで，いわゆるアナルトリーは生じなかった，2）アナルトリーは運動野の下部の皮質の刺激によってのみ生じた，3）口部顔面失行は運動野下部のみの電気刺激では出現しなかった，4）アナルトリーが認められた部位の刺激で仮名，漢字の字形想起障害，仮名の錯書が認められたが，恒常的ではなかった，5）第二前頭回脚部（Exnerの書字中枢）の刺激では書字障害は認められず語想起困難が認められた。

In 3 patients with brain tumors involving lan-guage areas, we investigated functional cortical regions and epileptogenic foci using subdural elec-trode stimulation befor operation. These stimula-tion studies were useful in preserving postope-ratively their language function. The following neu-ropsychological findings were obtained ; (1) Sti-mulation of Broca area (Brodmann 44 and 45) did not produce anarthria (phonetic disintegration), but semantic and phonemic parahasias and word finding difficulties. (2) Stimulation of lower motor cortex elicited anarthria. (3) Buccofacial apraxia was not produced only by stimulation of frontal operculum. (4) When anarthria was elicited by stimulation, difficulty in retrieving both Kana and Kanji letter-forms and paragraphia in Kana letters were sometimes observed. (5) Stimulation at Exner's writing centre did not produce writing deficits, but elicited word finding difficulties and paraphasias.