A Critical Appraisal of Neuropsychological Correlates of Japanese Ideogram (Kanji) and Phonogram (Kana) Reading

Abstract

Owing to the Japanese language's unique writing system, which consists of phonograms and ideograms, reading impairments of Japanese brain-damaged patients have attracted the interest of many researchers. Past case reports as well as some widely accepted handbooks and textbooks have concluded that a specific aphasia type or lesion site is associated with a particular impairment pattern of phonograms and ideograms in reading. However, the methodology and analytical procedures in previous studies were inadequate for reliable generalizations to be made. First, the test materials were unspecified or inappropriate, or the number of test items was small. Secondly, the conclusions were presented without providing individual performance data to support them. Thirdly, in associating patterns of reading impairment with lesion sites, only single cases were reported. The present investigation was designed to overcome the omissions of previous studies, and examined the ability to read 46 single phonograms and 46 single ideograms aloud in four groups of sufficiently large numbers of patients; namely, seven pure alexics, 23 Broca aphasics, 13 Wernicke aphasics, and seven patients with alexia and agraphia. Ours are the first data to demonstrate unequivocally no consistent linkage between aphasia type and the patterns of impairment of phonogram and ideogram reading. The impairment patterns were not uniform across patients even in the same aphasia group. A majority of the cases in each group showed that phonograms and ideograms were unselectively impaired. However, ideogram reading was more difficult in three cases in the pure alexia and Broca aphasia groups, respectively, and in one case in the Wernicke aphasia group. Phonogram reading was more severely disturbed in four cases among the Broca aphasics and in one case among the patients with alexia with agraphia. An apparent variability of impairment patterns characterized the Broca aphasic group. These dyslexic patterns did not appear to correlate with the site and extent of lesions identified by computerized tomography scans. Past reports linking a particular impairment pattern of phonogram and ideogram reading and a specific lesion site were studies of single cases, and their conclusions seem oversimplified. While sensory and motor dysfunctions can usually be neuroanatomically localized in individuals, impairments of certain high cortical functions, such as the reading of phonograms and ideograms, may not be correlated with damage to definite neuroanatomical structures.

Double Dissociation of Hangul and Hanja Reading in Korean Patients with Stroke

“…It has been criticized that previous reports correlating particular impairment patterns to the brain lesion of the patient seemed oversimplified [17]. Sugishita et al [17 ]argued that impairment of high cortical functions such as reading phonogram or ideogram might not be directly linked to the damaged structure.…”

“…Sugishita et al [17 ]argued that impairment of high cortical functions such as reading phonogram or ideogram might not be directly linked to the damaged structure. The authors postulated that complex cognitive functions accomplished through many interfaces on various stages of mental process related to the neural network, and that it may be too risky to match the cognitive dysfunction directly with the damaged area of the brain.…”

Subliminal Convergence of Kanji and Kana Words: Further Evidence for Functional Parcellation of the Posterior Temporal Cortex in Visual Word Perception

“…Also, several lines of studies have suggested the contribution of the right hemisphere in the visual recognition of logograms (Yamaguchi, Toyoda, Xu, Kobayashi, & Henik, 2002;Kamada et al, 1998;Nakagawa, 1994;Sugishita, Yoshioka, & Kawamura, 1986;Hatta, 1977;Sasanuma, Itoh, Mori, & Kobayashi, 1977). Nonetheless, the issue seems not fully resolved, as for instance, a more recent multiple case study found no consistent correlation between specific patterns of impairment and lesion sites (Sugishita, Otomo, Kabe, & Yunoki, 1992). In the brain imaging literature, moreover, although a few previous studies have examined brain activity during reading of Japanese (Sakurai, Momose, Iwata, Sudo, et al, 2000;Sakurai, Momose, Iwata, Ishikawa, et al, 1996; Sakurai, Momose, Iwata, ).…”

Hanja Alexia with Agraphia After Left Posterior Inferior Temporal Lobe Infarction: A Case Study

“…Many studies of phonogram and ideogram originated from Japanese in which dual orthographic system is employed; Kana (phonograms) and Kanji (ideograms) (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Japanese authors have found a double dissociation between Kana and Kanji impairments in brain-damaged patients and reported that Kanji is processed mainly in left posterior inferior temporal area (4)(5)(6)(7)(8)(9).…”

“…Japanese authors have found a double dissociation between Kana and Kanji impairments in brain-damaged patients and reported that Kanji is processed mainly in left posterior inferior temporal area (4)(5)(6)(7)(8)(9). On the contrary, there have been few studies on Korean written language (13,14), another orthographic system that also uses both phonogram (Hangul) and Chinese ideogram (Hanja).…”