Toru Mannen

Fusiform type alexia: pure alexia for words in contrast to posterior occipital type pure alexia for letters.

OBJECTIVE To clarify the behavioral differences between patients with pure alexia from different lesions. METHODS Two patients with pure alexia caused by damage to the fusiform or posterior occipital gyri were given reading and writing tests including kanji (Japanese morphograms) and kana (Japanese phonetic writing). RESULTS Patient 1 (pure alexia from a fusiform gyrus lesion) had difficulty reading both kanji and kana, with kanji reading more impaired, and imageability and visual complexity effects (imageable or less complex words/characters were read better than nonimageable or more complex words/characters), whereas patient 2 (pure alexia from a posterior occipital gyri lesion) showed selective impairment of kana reading. CONCLUSION Pure alexia for kanji (and kana; fusiform type) is characterized by impairments of both whole-word reading, as represented in kanji reading, and letter identification, and is different from pure alexia for kana (posterior occipital type) in which letter identification is primarily impaired. Thus, fusiform type pure alexia should be designated pure alexia for words, whereas posterior occipital type pure alexia should be designated pure alexia for letters.

Neuropathological findings of Onuf's nucleus and its significance

Onufs nucleus is a small group of cells which are located mainly in the anterior horn of the second sacral segment of the spinal cord. This paper describes the history of studies relating to this nucleus including a discussion of its relation with the various pathological studies which have been made.

Pure alexia for kana. Characterization of alexia with lesions of the inferior occipital cortex

OBJECTIVE To characterize reading impairments caused by lesions in the posterior occipital cortices. METHODS We gave six patients with these lesions reading and writing tests and located a critical site for alexia using MRI and SPECT. RESULTS The patients read three-character kana (Japanese syllabograms) nonwords, and five-character kana nonwords significantly or at a near significant level more poorly and slowly than normal subjects, whereas they read kanji (Japanese morphograms) almost correctly but more slowly. Letter-by-letter reading with a single-kana character identification impairment (in five patients), a word-length effect, kinesthetic facilitation, a lexicality effect, and minor to mild agraphia for kanji (in three patients) were observed. These deficits were characteristic of pure alexia. Alexia disappeared within a few months except in one patient who had extensive hypoperfusion in the left occipital lobe. A shared lesion was located in the left posterior fusiform/inferior occipital gyri (Area 18/19) on MRI, and there was blood flow reduction around this area on SPECT. This area coincided with the activation site for kana word covert reading in our previous study. CONCLUSIONS These results suggest that pure alexia particularly for kana, or more generally pure alexia for letters, is caused by a lesion in the posterior inferior occipital cortex, characterized primarily by impaired kana character or letter identification, with relatively preserved kanji or word recognition.

Isolated thalamic agraphia with impaired grapheme formation and micrographia.

Two patients with isolated thalamic agraphia are described. Both showed kanji (Japanese morphograms) agraphia due to impaired character recall, grapheme deformity and micrographia (progressive reduction in character size during writing) after a lesion that involved the ventral lateral and ventroposterolateral nuclei. Single photon emission computed tomography with a 99mTc-ethylcysteinate dimer revealed hypoperfusion in the left precentral gyrus (Brodmann Area 6) and anterior supramarginal gyrus in both. Six months later, the extent of blood flow reduction decreased in the supramarginal gyrus in both patients and the precentral gyrus in patient 1. By this time, the writing impairment improved to nearly the normal range. Our study suggests that kanji agraphia (corresponding to lexical agraphia in Western countries) with poor grapheme formation and micrographia arises from a lesion in the ventral lateral and ventroposterolateral nuclei in the left thalamus. The accompaniment of poor grapheme formation and micrographia may reflect disruption of the cortico-subcortical motor circuit involving the putamen, thalamus, premotor cortex and sensorimotor cortex. It is also suggested that multiple cortical sites can be a target for secondary dysfunction that yields agraphia in a thalamic lesion, and that the recovery of reduced cortical blood flow does not always proceed in parallel with that of agraphia.

Ubiquitin-positive frontotemporal lobar degeneration presenting with progressive Gogi (word-meaning) aphasia. A neuropsychological, radiological and pathological evaluation of a Japanese semantic dementia patient

A patient with progressive anomia and alexia with agraphia for kanji (Japanese morphograms) is described. The patient showed a deficit in single-word comprehension and on-reading (a type of reading that conveys phonetic value) dominance in kanji reading, i.e. on-preceding (pronouncing first with on-reading, irrespective of its preferred reading) and kun-deletion (inability to recall and recognize kun-reading [another type of reading that conveys meaning]) when reading a single-character kanji. These features were due to loss of lexico-semantic information and thus the patient was regarded as having progressive Gogi (word-meaning) aphasia by Imura, a Japanese manifestation of semantic dementia. Macroscopically, neuropathological examination disclosed atrophy of the left frontotemporal lobe with accentuation in the anterior portion of the temporal lobe. Histologically, there was neuronal loss in the cerebral cortex, hippocampus, parahippocampal gyrus, amygdala, caudate nucleus, and putamen. Ubiquitin-immunoreactive neuronal inclusions were present in the hippocampal dentate granular cells. This case demonstrates that progressive Gogi aphasia is semiologically identical to semantic dementia, and our patient clinicopathologically resembled those of Rossor et al. [Rossor, M.N., Revesz, T., Lantos, P.L., Warrington, E.K. Semantic dementia with ubiquitin-positive tau-negative inclusion bodies. Brain 2000; 123: 267-76.] and Hodges et al. [Hodges, J.R., Davies, R.R., Xuereb, J.H., Casey, B., Broe, M., Bak, T.H., et al. Clinicopathological correlates in frontotemporal dementia. Ann Neurol 2004; 56: 399-406.].

Impaired laryngeal voice production in a patient with foreign accent syndrome

We report a Japanese-speaking monolingual woman who developed foreign accent syndrome (FAS) following an infarction in the precentral and premotor cortices (Brodmann Area 6) at and around the inferior frontal sulcus. Her speech sounded Chinese or Korean to our bilingual coauthor who speaks Chinese and Japanese. Quantitative acoustic analyses of words and sentences showed that pitch (fundamental frequency variation) and intensity variances appeared lowered and fully voiced glottal pulses were reduced. These findings suggest laryngeal dysfunction that contributes to the unusual speech production in a case of FAS. This may be caused by damage to a restricted area of the motor and premotor cortices that controls laryngeal function.

Progressive apraxic agraphia with micrographia presenting as corticobasal syndrome showing extensive Pittsburgh compound B uptake.

A 65-year-old woman developed progressive apraxic agraphia, characterized by poorly formed graphemes, a kanji (Japanese morphograms) recall impairment, relatively preserved oral spelling of kanji characters, and incorrect stroke sequences on writing accompanied by micrographia over a 3-year period. She also showed minor degrees of rigidity, limb-kinetic apraxia, and ideomotor apraxia of the left hand. Although asymmetric rigidity and limb-kinetic apraxia strongly suggested corticobasal degeneration, 11C-Pittsburgh compound B positron emission tomography (PiB-PET) showed the predominantly right-sided accumulation of amyloid β in the cortices and striatum. 18F-fluoro-deoxy-glucose PET and single photon emission computed tomography with a 99mTc-ethylcysteinate dimer (ECD-SPECT) also revealed predominantly right-sided hypometabolism and hypoperfusion in the primary sensorimotor cortex, posterior cingulate gyrus, temporoparietal cortices, frontal cortices, thalamus, and basal ganglia, a pattern characteristic of both corticobasal degeneration and Alzheimer’s disease. The findings suggest that progressive apraxic agraphia with micrographia presenting as corticobasal syndrome can show an Alzheimer’s disease pathology. It is also suggested that ideomotor apraxia of the left hand can occur without a callosal lesion, and is caused by hypometabolism or hypoperfusion in the right frontal and parietal cortices, as revealed by PET and SPECT.