Dysgraphia in Korean patients with Alzheimer's disease as a manifestation of bilateral hemispheric dysfunction.
BACKGROUND
In writing, linguistic (i.e., spelling) and nonlinguistic (i.e., arranging strokes or letters) functions are processed by the left and right hemispheres, respectively. The configuration of Korean alphabet, 'Hangul' invokes nonlinguistic, visuospatial functions that other writing systems use less extensively. Patients with Alzheimer's disease (AD) have bilateral involvement of temporoparietal-frontal areas that are responsible for processing language and visuospatial functions.


OBJECTIVE
The aim of this study was to examine the nature of Hangul writing dysfunction, which may be associated with bilateral hemispheric impairments in AD.


METHODS
A sample of 75 patients with AD and 20 healthy controls (HC) performed a Hangul writing task. Neuroimaging positron emission tomography (PET) data of 22 patients were utilized to measure the regional brain glucose metabolism associated with Hangul writing.


RESULTS
The writing performance of the AD group was significantly reduced and different types of errors were observed as the disease got worse. Glucose hypometabolism correlated with Hangul writing impairment was located in the right occipitotemporal lobe and left temporoparietal lobe.


CONCLUSIONS
The PET findings demonstrate that impairment in Hangul writing performance in Korean AD patients is closely related to a functional decline in both the right and left hemispheres. The study provides a unique contribution to the knowledge of dysgraphia in a non-alphabetical writing system as well as the underlying neuropathology of dysgraphic features in such languages.
Graduate Program in Speech and Language Pathology, Yonsei University, Seoul, Republic of Korea.
Ji Hye
JH
Yoon
Hyanghee
H
Kim
Sang Won
SW
Seo
Juhee
J
Chin
Jung-Hyun
JH
Kim
Kyung-Han
KH
Lee
Yong Wook
YW
Kim
Eun Sook
ES
Park
Mee Kyung
MK
Suh
Duk L
DL
Na
D000368:Aged; D000369:Aged, 80 and over; D000381:Agraphia / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000544:Alzheimer Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D044466:Asian People / Q000523:psychology; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D059907:Functional Neuroimaging / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D049268:Positron-Emission Tomography / Q000379:methods / Q000706:statistics & numerical data; D011597:Psychomotor Performance / Q000502:physiology; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18