與認、讀、寫分離的比手勢缺損：一位失語症個案的數字表現

Deficit in Gesturing of Numbers Dissociated from Recognizing, Reading and Writing: An Aphasia Case Study

說、讀、寫分離的現象早獲證實，近代研究也顯示讀和比手勢有分離的現象，亦有少數文獻發現數字的讀與寫也可互為獨立，但數字的手勢與讀寫的關係則有待探究。此篇個案研究目的為探討手勢和閱讀以及書寫之間的關係。研究對象為一位左腦傷男性大學生，被診斷為左額葉動靜脈畸形，接受栓塞治療，之後於原處出血並伴隨腦室內出血與水腦，又因腦腫脹而於左腦額葉－顳葉－頂葉－枕葉位置進行減壓的顱骨切除手術與硬膜強化。個案於語言理解和表達皆有困難，患側手雖有輕微震顫，但可獨立運筆且手部動作沒有受限；空間知覺良好，身體基模（body schema）有輕微缺損，手指基模（finger schema）正常，但手指命名有困難。我們採取類似單一受試研究法中的輪替設計，設計出與數字有關且難易度合乎個案能力的實驗，內容包含讓個案執行「看數字唸出」、「聽數字寫出」和「聽數字用手勢比出」等三種任務，並記錄其正確率及反應時間。實驗採用隨機分配、重複施測和對抗平衡的設計。根據實驗結果，個案看到數字時幾乎每次皆可唸出正確讀音，聽寫數字的平均表現則稍差一些，反應時間也較長，而表現最差的部分是比出數字，正確率高低落差大、較不穩定。此結果證實，個案於數字與手勢的理解只有輕微問題，但在數字的閱讀、書寫和比手勢輸出卻有分離的情形，對於一樣的刺激輸入，即聽到相同的數字，個案在口語輸出、用筆寫出和用手勢比出的表現不一致，顯示三部份各有其獨特性，也證實了數字的手勢與認讀寫可互為獨立。

The dissociations between speech, reading and writing have been proposed, and recent studies also showed the differences between the neural mechanisms of reading and gesturing. The purpose of this study was to justify whether the mechanism of gesturing numbers is dissociated from that of recognizing, reading or writing numbers by conducting experiments on an aphasic patient who suffered from left frontal arterio-venous malformation and received embolization treatment. However, bleeding and IVH came after the embolization treatment. Therefore, the craniotomy was done again and the left F-T-P-O decompressive craniotomy and dural augmentation were performed due to brain swelling. Although the brain damage is severe, this did not bother him to meet the cognitive and motor demands on all the tasks in this present study. A single subject alternating treatments design was employed to compare the differences of number performance among reading, writing and gesturing. Totally, the participant conducted 12 runs of these three tasks in counterbalanced and randomized order to avoid practice effects and serial position effects. The results presented that the participant could recognize and read almost every number correctly and quickly. While writing and gesturing numbers, the accuracy became lower, and the reaction times were taken longer. Besides, his performance in twelve trials of gesturing numbers was inconsistent. The findings of this study implied that the participant’s abilities of number reading and gesture comprehension are almost intact but the ability of number gesturing seems severely impaired. Therefore the dissociation of gesturing numbers from reading and writing numbers can be inferred.