Neurocase. 2003 Aug;9(4):297-307.
Caccappolo-van Vliet E, Miozzo M, Marder K, Stern Y.
Cognitive Neuroscience Division, Taub Institute for Research in Alzheimer’s Disease and the Aging Brain, New York, NY, USA.
RB, a patient with probable Alzheimer’s disease, makes continuous perseverations of single letters when writing (e.g. fruit–>fruuit), particularly on high frequency letters. An analysis of her errors reveals that her perseverations do not reflect letter substitutions or transpositions, nor do they suggest difficulty with geminates. No continuous perseverations were found in oral production, in graphic and simple motor tasks, and in oral spelling. RB’s data do not support an attention deficit as the basis of her continuous perseverations. It is proposed that a deficit at the level of abstract letter representations is the source of RB’s perseverations. The implications of this conclusion for accounts of perseveration and of spelling models are discussed.
PMID: 12925943 [PubMed – indexed for MEDLINE]