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P1‐188: Limitation of vertical reading in a patient with progressive supranuclear palsy (PSP)
Author(s) -
Chung Eun Joo,
Kang Heeyoung
Publication year - 2012
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2012.05.466
Subject(s) - horizontal and vertical , fixation (population genetics) , saccade , reading (process) , gaze , psychology , eye movement , fluency , audiology , cognitive psychology , computer science , medicine , artificial intelligence , neuroscience , population , linguistics , mathematics , philosophy , geometry , environmental health , mathematics education
Background: Many studies show slow saccades in PSP, especially in the vertical direction, even in early stages of the disease, a finding attributed to pathologic involvement of brainstem burst neurons. Reading involves a succession of saccades and fixations. Korean (Hangul) is able to read to vertical and horizontal script contrary to alphabetic script. Thus, lack of binocular coordination of saccades in patients with PSP would cause fixation disparity and could interfere with visual processing of the letters. We hypothesized that vertical reading may have more delayed reading time and much more reading errors than horizontal reading in PSP. Methods: A 68-year-old man visited had been diagnosed as PSP from 2 years ago. On neurologic examination, he showed vertical saccade limitation, especially down gaze. MMSE score was 24 and neuropsychological test showed predominantly visuospatial and frontal executive dysfunction. However, he did not show language deficits. Eye examination Experiment I (Visual scanning: voice analysis): Firstly, we prepared twelve different horizontally aligned and corresponding vertically aligned a word for test (Total 24 words). Each paragraph randomly presented on a computer with full-screen full-luminance white background. And then, patient read aloud watching a word on the monitor. We checked a reading time and reading errors. In the same manner as above, we studies vertical and horizontal paragraph reading. Experiment II (Visual scanning: visual analysis): We recorded saccades in patient using by eye tracker. For analysis of the horizontal and vertical saccade, patient had read paragraphs according to sequence of horizontal, vertical, vertical and horizontal. Results: In voice analysis, there was significantly different reading time (second) between horizontal reading and vertical reading of words (60.17 6 6.25 vs. 66.75 6 7.47, respectively, p 1⁄4 0.029) and paragraphs (52.17 6 3.46 vs. 128.336 3.49, respectively, p<0.0001), each other. Patient showed a decreased vertical saccade velocity and reduction of amplitude of the eye movement. Conclusions: One interesting thing was that vertical reading time of words was more delayed than horizontal reading time. These results mean that vertical reading of PSP patient may be depended more on vertical gaze palsy according to the visual structure of Korean characters.