Reversible dissociation of sensitivity to dynamic stimuli in Parkinson's disease: is magnocellular function essential to reading motion-defined letters?

Vision Research
D GiaschiD Regan

Abstract

A group of 20 control subjects carried out the following visual tests: Snellen acuity; contrast detection threshold for a temporally unmodulated grating and for a temporally modulated grating; speed threshold for recognising motion-defined dotted letters. Normal limits were defined as 2.5 standard deviations from the respective control means. A patient with Parkinson's disease carried out the tests 12 hr after medication was withheld at a time when symptoms were evident ("off" stage), and after administration of medication when it had taken full effect ("on" stage). Confirming previous reports, contrast detection threshold for the temporally modulated grating was much higher during the "off" stage than during the "on" stage, but contrast detection threshold for the temporally unmodulated grating showed little difference. Speed threshold for recognising motion-defined letters did not, however, fall during the "on" stage. We suggest that magnocellular function is not essential for the recognition of motion-defined form.

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Citations

Jan 6, 2000·Journal of the Neurological Sciences·V PieriC G Goetz
May 30, 2001·Survey of Ophthalmology·C A Johnson
Jun 15, 2006·Optometry and Vision Science : Official Publication of the American Academy of Optometry·Amy E ZwickerDeborah E Giaschi
Sep 30, 2008·Neuropsychologia·Miguel Castelo-BrancoAntónio Freire
Mar 23, 2005·Vision Research·Cindy S HoChristopher Lyons
Jan 13, 2005·Vision Research·E E ParrishR Dougherty
Apr 11, 2003·Primates; Journal of Primatology·Shumpei UnnoAkichika Mikami
Jan 19, 2021·Progress in Retinal and Eye Research·Amir H KashaniJohn M Ringman
May 29, 2020·Clinical Parkinsonism & Related Disorders·Mosaad AlhassanQuincy J Almeida

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