Human memory is considered to consist of several separate but interacting systems. The multiple-system views of memory have attempted to organize various dichotomous classifications, such as episodic/semantic, declarative/procedural, and implicit/explicit, into more comprehensive classificatory schemes. Yet the structure of long-term memory remains a matter of controversy. In this paper three issues are discussed. First, it is still open to debate whether episodic and semantic memory represent two separate systems or the same system operating under different circumstances. Second, recent research has revealed the hierarchical structure of autobiographical knowledge base, and at least three layers of knowledge have been identified. Finally, amnesic patients have been found to be capable of learning new semantic information, suggesting that semantic knowledge can be acquired without functioning episodic memory system.

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    Based on the analysis of recovery process in patients with tansient grobal amnesia, there were periods during which patients had anterograde amnesia without retrograde amnesia ( ‘isolated anterograde amnesia’ ). We also presented two cases of isolated retrograde amnesia resulting from probable encephalitis. Taken together, it seems that anterograde amnesia and retrograde amnesia may be exist independently and produced anatomically different structures.
    A case with circumscribed temporal atrophy show impairment of social memory with relatively unaffected autobiographical memory. Patients with Alzheimer's disease show defect of both social memory and autobiographical memory with temporal gradient. Social memory and autobiographical memory may be impaired independently.
    Analysis of cases with isolated retrograde amnesia and neurodegenerative diseases led us to the following speculations that the responsible lesion for retrograde amnesia is within the temporal lobe.

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    In this study, we investigated fifteen patients with a variety of organic brain diseases, exhibiting confabulations. The relation of confabulation measured by structured inquiry battery to error contents of semantically related paired association learning test (PAL) was statistically examined. Results was as follows : the performance of the PAL correlated with incidence of correct answers but not that of confabulations in the inquiry battery ; confabulations elicited by questions concerning remote memory was correlated with extralist perseverations semantically unrelated to the target in the PAL ; factor analysis revealed a postitive relationship between factor 2 (confabulations to the recent memory, heightened suggestibility, and comprehension of one's immediate surroundings) and amnestic syndrome without dementia. This supported the view that there were two types of confabulations. We proposed that the one was a traditional embarrassment confabulation, preferentially elicited by questions concerning recent memory and that the other was closely correlated with a loosening of semantical framework just as observed in SDAT. Not only retrieval of recent memory but also that of remote memory elicited confabulatory response in the latter type.

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    We reviewed the advantages and disadvantages of various techniques devised for investigating remote memory. Several problems are crucial for using and interpreting remote memory tests. For example, when we use tests for public and social memory, the degree of individual interest is fundamental. The veracity of recollections is especially important when we use tests for autobiographical memory tests. Ceiling effect by the control subjects should be considered in case the task is quite easy. On the other hand, floor effect by amnesia patients will give us no information about temporal gradient of their remote memory performances. Take these problems into consideration, we introduced autobiographical fluency task, which is the fluency-based remote memory tests. Subjects are asked to recall the memories about autobiographical aspects as much as possible for 1 minute. Using Fluency-based remote memory tests, we can avoid ceiling effect by control subjects. There were significant correlations between the performances on the autobiographical fluency test and the performances on previously studied autobiographical memory test in ten alcoholic Korsakoff patients. We conclude that the fluency-based remote memory tests are useful to assess remote memory.

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    This study investigated the process of recovery in conduction aphasia and discussed the underlying mechanism of disorders in conduction aphasia from two standpoints. One is change in phonetic speech error ; the other is change in performance on the auditory verbal short-term memory (STM) test in the course of recovery. The subjects were two male conduction aphasia patients, ages 45and 55. Both were diagnosed with conduction aphasia after the onset of a cerebral infarction which manifested a severe phonological disorder in spite of a well-preserved semantic system. We prepared two kinds of test. One consisted of confrontation naming, repetition, reading aloud of kanji words and reading aloud of kana words using the same 20 materials (speech analysis test). The other was an auditory verbal short-term memory span test (STM test) using numbers and words which represented the names of vegetables, in which the subjects were asked to respond by repetition and pointing. We administered the two tests several times, to one subject over 14 months and to the other over eight months after onset of aphasia.
    The results were as follows. (1) In the speech test, with improvement in performance, unsupposed responses, omissions and additions in errors decreased, and partially correct responses, displacements and transpositions increased, in both subjects in all four subtests. (2) In the STM test, performance in repetition, which was worse than performance in pointing at first, improved gradually. These results suggest that phonological disorders in conduction aphasia patients recover in two stages : the first in which they are unable to retrieve even individual phonemes and the second in which they have difficulty in choice and disposition of phonemes. Also, the fact that phonological disorders and declines in performance on STM tests were discovered in parallel suggests that phonological disorders in conduction aphasia cause short-term memory disorders.

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    We reported a case of mumbling jargon. The subject was a 63-year-old right-handed woman. The study investigated the mechanism underlying the subject's mumbling jargon mainly from three viewpoints : auditory comprehension intimately related to monitoring of speech activity, personality effects on communication activity, and intentional phonetic motor control.
    We concluded that it is difficult to explain this case of jargon by the present monitoring deficit theory based on auditory feedback, because auditory comprehension is well preserved. The jargon of this patient is thought to be associated with personality ; she tends to focus tenaciously on things, and demonstrates impatience and restlessness. From the viewpoint of speech function, the jargon is associated with intentional phonetic motor control deficit. In addition to the foregoing two factors, it is speculated to be associated with plural factors of inner language disorder at various levels : syntax, meaning, phonemes and so on.

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    Trough 10years of experience in group therapy at the Chofu City General Welfare Center, we prepared criteria for an original psychosocial assessment form. Here its reliability is examined. The form consists of five categories including attitude in participation, interpersonal consciousness, emotion, self-perception and acceptance of disability, plus 15 subcategories.
    First, 17 chronically aphasic persons participating in our group therapy were evaluated using this assessment form. Second, we analyzed the relation between duration of group therapy experience and degree of success at achieving good levels. Also patterns of assessment profiles were examined carefully. The results were as follows. (1) Psychosocial problems of aphasic persons such as reduction in self-esteem, resistance against self-disclosure, adherence to disability, and stubbornness were clearly observed. (2) These problems were noticeably demonstrated by severe aphasic persons and those attending group therapy less than two years, but the tendency that longer group experience reduced difficulties was also observed. (3) In view of our study, this assessment form is useful for the following : detecting individual psychosocial situations and changes during group therapy ; establishing understanding and consensus on each client's problems among staff ; evaluating the effectiveness of group therapy easily.

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    The auditory resolution performance of 31 aphasic patients was measured using the click fusion test, and compared with severity of verbal comprehension disturbance (auditory retention span : ARS). The controls were 15 cases with right hemisphere lesion (RHL) and 13 normals. The CFT of the aphasic patients was significantly worse than that of the normals (p=0.0018) , but was not different from the RHL cases with no verbal comprehension disturbance (p=0.0779). In the aphasic patients, there was no correlation between severity of verbal comprehension (ARS) and CFT (r=—0.135, p=0.4737). Lesions of the medial geniculate body or of the medial part of the auditory radiations, as well as lesions of the extensive regions of the transverse temporal gyrus or of the superior temporal gyrus of the left hemisphere produced disturbance of CFT in both bilateral simultaneous stimulation and right unilateral stimulation. Lesions of the lateral part of the auditory radiations, as well as partial lesions of the upper part of the transverse temporal gyrus or of the superior temporal gyrus of the left hemisphere seemed to yield disturbance of CFT only in the right ear presentation condition. From these findings, it was concluded that 1) disturbance of auditory resolution of bilateral ears results from extensive unilateral damage to the auditory systems, and that 2) verbal comprehension performance of aphasic patients is dependent upon both auditory resolution capacity and phonemic recognition performance, although the effect of the latter seems to be significantly stronger.
    For another measurement procedure of auditory resolution performance, click counting test (CCT) was used in some reports. However, our data suggested that the score of the test was decreased by the lesion of the frontal lobe.

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    A 55-year-old right-handed male was admitted with mutism and right lower extremity weakness. In the chronic phase, pathologic grasping phenomenon of the right hand, intermanual conflict caused by the right-hand interference and transcortical motor aphasia were observed. MRI demonstrated several tiny, speckled lesions in the deep white matter of the left anterior cingulate gyrus and the corpus callosum. Cerebral angiography revealed occlusion of the left internal carotid artery with collateral circulation from the right internal carotid and basilar arteries. IMP-SPECT showed decreased blood flow in the left internal carotid artery distribution. Four similar cases characterized by intermanual conflict caused by the right-hand interference and transcortical motor aphasia have been reported previously. Our case and these literature cases share some features, i. E., right-handedness, pathologic grasping phenomenon of the right hand, responsible lesions in the left anterior artery territory, initial symptoms and favorable outcome, in addition to intermanual conflict caused by the right-hand interference and transcortical motor aphasia. These findings suggest these cases might be regarded as a unique syndrome characterized by two symptoms : intermanual conflict caused by the right-hand interference and transcortical motor aphasia.

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