Post-stroke Chinese pure alexia: linguistic features and neuropsychological profiles.

PURPOSE: Very few cases of Chinese pure alexia have been reported to date. We aim to summarize the linguistic features and neuropsychological profiles of Chinese pure alexia through a case series study. METHODS: 11 consecutive patients with post-stroke Chinese pure alexia and 11 healthy controls were included. The Aphasia Battery of Chinese (ABC) and 68-Chinese character oral reading test (68-character test) were used to evaluate the reading and writing ability. Reading errors were classified based on the performance of 68-character test. Neuropsychological profiles were evaluated with corresponding scales. The possible correlation between the reading ability and the writing ability or neuropsychological performance was analyzed. RESULTS: The patients had a correct rate of 43.7 ± 23.2% in the 68-character test, significantly lower (P < 0.001) than that of controls. Shape-similar error was the most common type of reading error (101/209, 48.3%). The ABC total writing score rate of the patients ranged from 68.9% to 98.7% (median, 90.5%), significantly lower (P < 0.001) than that of the controls. The patients also showed worse performance in MMSE, auditory verbal learning test, Boston naming test, intersecting pentagons copying and clock-drawing test (all P < 0.05). In the patient group, the correct rate of 68-character test was significantly correlated with the ABC total writing score rate (P = 0.008), the score rate of Boston naming test (P = 0.017), and the clock-drawing test score (P = 0.010). CONCLUSION: Shape-similar errors may be a characteristic of Chinese pure alexia. The correlation between visuospatial dysfunction and pure alexia might explain the frequent occurrence of shape-similar errors in Chinese pure alexia.

Pure alexia with intact perception of complex visual stimuli: a case study.

After a stroke involving the left occipitotemporal cortex our patient shows a word-length effect and has problems to identify letters or numbers in strings of symbols. But he is normal in identifying isolated letters and in non-verbally categorizing even complex images such as faces or natural scenes. His cortical lesion is stretching from the visual word form area (VWFA) anteriorly causing additional problems to name visual stimuli and to match acoustic stimuli with images. We conclude that our patient suffers from pure alexia without deficits to identify even complex visual stimuli. Our results directly contradict several explanations for letter-by-letter reading.

Alexia Without Agraphia in a Right-Handed Individual Following Right Occipital Stroke.

Alexia without agraphia is a disconnection syndrome that typically involves damage to the occipital lobe, with splenium involvement, in the dominant left hemisphere. We describe an exceptionally rare case of a right-handed individual displaying this deficit following a right-sided occipital stroke. A report of a single case of a 65-year-old man is presented with data from appointments with the neurology and neuropsychology departments that occurred approximately 10 and 12 months following the patient's stroke. During the evaluation, he exhibited a marked deficit in his ability to read, with vision grossly intact. His ability to write single words and short phrases from dictation was intact, but he was later unable to read them. This case demonstrates the complexity of the organization of language in the human brain. Although a large majority of individuals exhibit language dominance in their left hemispheres, it remains possible that some right-handed individuals may show atypical organization of language. This highlights the need for clinicians to consider atypical cortical organization when observed deficits may not necessarily match expected lesions within the cortex.

Fast word reading in pure alexia: "fast, yet serial".

Pure alexia is a severe impairment of word reading in which individuals process letters serially with a pronounced length effect. Yet, there is considerable variation in the performance of alexic readers with generally very slow, but also occasionally fast responses, an observation addressed rarely in previous reports. It has been suggested that "fast" responses in pure alexia reflect residual parallel letter processing or that they may even be subserved by an independent reading system. Four experiments assessed fast and slow reading in a participant (DN) with pure alexia. Two behavioral experiments investigated frequency, neighborhood, and length effects in forced fast reading. Two further experiments measured eye movements when DN was forced to read quickly, or could respond faster because words were easier to process. Taken together, there was little support for the proposal that "qualitatively different" mechanisms or reading strategies underlie both types of responses in DN. Instead, fast responses are argued to be generated by the same serial-reading strategy.

Is radical-by-radical reading strategy effective for Chinese pure alexia? A case study.

OBJECTIVE: Currently, it is unclear whether a radical-by-radical (RBR) reading strategy exists in Chinese pure alexia, compared to the letter-by-letter (LBL) reading strategy in alphabetic languages. In this study, we focus on exploring the reading features of a Chinese pure alexic patient during the process of language recovery. METHOD: We investigated this issue using a series of neuropsychological tests at 4 days, 11 days, and 8 months after admission of a Chinese pure alexic patient. RESULTS: The results showed that most words could not be read aloud initially by the patient. One week later, 2 clinical features were noted: RBR reading strategy and integration impairment. Finally, there were statistically significant differences in the reaction time between the single characters and compound characters, which indicated that a radical number effect may exist. CONCLUSION: Combined with the results of previous studies, the current case study indicates that there is evidence suggesting that the RBR reading strategy in Chinese pure alexia is of limited benefit, a result that appears fundamentally different from the LBL reading strategy.

Fluorodeoxyglucose F18 positron emission tomography in a case of slowly progressive pure alexia.

We describe a 71-year-old patient with slowly progressive pure alexia in which analysis of her fluorodeoxyglucose FDG-PET scan revealed an area of focal hypometabolism in the visual word form area. She presented with difficulty reading. Examination revealed pure alexia with preservation of other cognitive domains. Brain MRI revealed only slight atrophy. A Fluorodeoxyglucose F18 positron emission tomography scan revealed hypometabolism in the occipital cortex bilaterally, left greater than right, with normal metabolism elsewhere in the brain. This case highlights the utility of FDG-PET scan in evaluating focal neurodegenerative conditions before clear atrophy can be seen on MRI.

[Neurolinguistic features during recovery of a Chinese patient with pure alexia].

OBJECTIVE: To analyze the neurolinguistic features of a Chinese patient with pure alexia in acute and convalescent stages. METHODS: We assessed the reading and writing abilities of the patient with the Aphasia Battery of Chinese (ABC), the reading examination of Chinese characters (1999, Lin) and the Chinese agraphia battery (CAB). RESULTS: In the ABC examination in the acute phase, the patient performed well in oral expression and comprehension, and the prominent linguistic abnormalities were alexia and merging agraphia; in the convalescent phase, the recovery of alexia was better than that of agraphia. In reading examination of Chinese characters, shape errors were the main reading disorders in the acute phase with a few semantic errors, regularization errors and mistakes in pronunciation, but only shape errors reappeared in the recovery period. CAB examination showed impairment of writing for pictures and dictation abilities in the recovery period but recovery of other writing abilities. The writing disorder was manifested as aphasic agraphia, with obvious dysorthography and lexical errors; the patient was capable of spontaneous writing only after spontaneous speech, and was able to read the written words. CONCLUSION: The linguistic components of the Chinese patient with pure alexia showed different patterns of damage and recovery, suggesting the difference in their respective neuropsychological pathways.

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.

Visually- and motor-based knowledge of letters: evidence from a pure alexic patient.

We describe a patient, VSB, whose reading was impaired as a consequence of a left temporal-parietal lesion, whereas writing was relatively preserved. At variance with other pure alexic patients described in the literature, VSB claimed to have become unable to mentally visualise letters and words. Indeed, his performance on a series of tests tapping visual mental imagery for orthographic material was severely impaired. However, performance on the same tests was dramatically ameliorated by allowing VSB to trace each item with his finger. Visual mental imagery for non-orthographic items was comparatively spared. The pattern of dissociation shown by VSB between impaired visual mental imagery and relatively preserved motor-based knowledge for orthographic material lends support to the view that separate codes, respectively based on visual appearance and on motor engrams, may be used to access knowledge of the visual form of letters and words.