音読課題において異なる誤反応パターンを示した純粋発語失行例の検討

A Study of Pronunciation Errors in the Reading of Kanji Words in Cases with Pure Apraxia of Speech

音読に際して異なる誤りを呈した2例の純粋発語失行例を報告した。症例Aは多彩な音の誤り（置換・歪み・省略）を生じ，症例Bは主に長母音の省略とピッチの誤りを認めた。2例の病巣部位は，左中心前回の中で異なっており，症例Aは左中心前回の前壁を除く後部からやや深部に，症例Bは左中前頭回および中心前回前部を含む深部白質であった。誤りのパターンを中心前回での病巣の違いから検討した。

Abstract

In this study we investigated the pronunciation error patterns in Kanji words of two patients with pure apraxia of speech. We asked the patients to read aloud 80 visually presented Kanji words, half of which were homonymous and the rest non-homonymous. The words were presented at three different intervals (2, 1.5 and 1 sec.). Case A, a 68-year-old right-handed woman, produced a variety of sound errors - substitution, distortion and omission - and some errors of pitch position. Case B, a 73-year-old right-handed woman, omitted the prolonged vowels of each word, and produced many pitch errors, including pitch position errors and flattening of pitch. Each patient had different lesions in the left precentral gyrus - Case A from the posterior bank to the middle part of the left precentral gyrus, and Case B in the anterior bank and deep white matter of the left precentral gyrus. We speculated that Case A has difficulty mainly in the articulation process and vocalization, whereas Case B's deficit lies mainly in the phonation process, which relates to control of pitch and expiration.