Saturday, January 30, 2010

Gerstmann's syndrome reader

Kombos T,  Picht t, Suess O.  Electrical Excitability of the Angular Gyrus. Journal of Clinical Neurophysiology 25(6) December 2008 .
Comment.  This is the first report of direct electrical stimulation of AG in humans. Stimulation resulted in responses in contralateral upper extremity in 3/5 patients.  No lower extremity stimulation was found.

Anema HA.a,  Kessels RPCcd, de Haan EHFe,  Kappelle L,  Leijten F, van Zandvoort Martine , Dijkerman,H.  Differences in finger localisation performance of patients with finger agnosia

 19(14) September 2008 . 
Comment : 3 patients with AG lesions were able to point with their finger effectively
to  a tactile stimulus (body schema intact) but unable to do so with a drawing  of hand or to name the finger. 
Other body parts did not have this dissociation between body schema and body image.

Tamura I, Kikuchi S, Otsuki M, Tashiro K. The writing of arabic numerals, kanji, and kana in brain-damaged patients. 14(6), 6 May 2003, pp 861-865.
Comment.  4 patients with Gerstmann's syndrome and 4 with Wernicke's aphasia were compared.  All patients could copy letters, and were righthanded.  Subjects were presented with coins, and then asked to write the respective number value in kana , Kanji and Arabic numerals. For GS patients, kanji writing was better than Arabic, that was better than kana writing.  For WA aphasia patients, Arabic numeral writing was better than kana and kanji. Discussion: "In the case of GS, there was a problem in the concept of number.  In the case of WA, the concept of number was relatively well preserved." GS subjects made substitution errors in Arabic number writing.  Authors postulate a deficiency processing recall of somesthetic graphemes linked to the  concept of number.

Wingard E, Barrett  A, Crucian G, Doty, L, Heilman, KM.  The Gerstmann syndrome in Alzheimer's disease. Journal of Neurology, Neurosurgery & Psychiatry  72(3) March 2002 .
Comment  :  among 38 patients with Alzheimer's disease, the four constituent components of Gerstmann's syndrome did not cluster together, leading the authors to speculate that their association is fortuitous due to contiguous networks, and that the four features of Gerstmann's syndrome do not share a common network.

Baciul M, Koenig O, Vernier M,  Bedoin N, Rubin C, Segebarth C. Categorical and coordinate spatial relations: fMRI evidence for hemispheric specialization. Neuroreport 10(6) April 1999.
Comment: 16 healthy males were examined on a coordinate and a category task using fMRI paradigm.  The category task was whether a dot was above or below a horizontal line. The coordinate task was whether the distance between the dot and the line was within a reference distance.  The coordinate task related to right AG activation which decreased over time.  The category task depended upon Left AG activation which did not decrease over time and in fact increased over time.  Results subserve the hypothesis that the left hemisphere subserves the development of new spatial categorization.

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