Gogi (Word Meaning) Aphasia and Its Relation with Semantic Dementia

In 1943, Tsuneo Imura, a neuropsychiatrist at Tokyo University, proposed a new aphasic syndrome and designated it as Gogi (word meaning) aphasia. According to Imura, it is characterized by (1) difficulty in comprehending spoken words despite good perception of sound, (2) disorders of expression due to loss of vocabulary and verbal paraphasia, (3) preserved ability of repetition, and (4) selective difficulty in reading and writing kanji (Japanese logographic character) with preserved ability of reading and writing kana (Japanese syllabic character). To be more specific, the difficulty in comprehending spoken words in Gogi aphasia is limited to substantive words as the name of the syndrome indicates, while comprehension of syntax remains unimpaired. Preserved repetition ability cannot be simply regarded as an automatic response, that is, echolalia, because the patient's attitude in repeating was quizzical, picking up the particular word he did not comprehend. Imura vaguely attributed the responsible lesion to the second and third temporal gyri on the left side. Although the general pattern of the syndrome can be placed in the category of transcortical sensory aphasia, its uniqueness as the syndrome still stands out. Another uniqueness of the syndrome is its characteristic pattern of dissociated kanji-kana difficulty in reading and writing. This linguistic symptomatology observed in Gogi aphasia was first introduced to the western academic world on a German neuropsychiatric journal by Panse and Shimoyama in 1955. Ever since, the existence of Gogi aphasia as an independent syndrome among disorders of spoken language has gradually gained international recognition. But whether the pattern of the kanji-kana dissociation described by Imura is an integral part of the syndrome remains unsettled. A recently proposed concept of semantic dementia suggests symptomatic continuation of word meaning loss with non-linguistic semantic memory loss.