Eye movement behaviour during reading in patients with probable Alzheimer disease

FERNANDEZ GERARDO; SCHUMACHER MARCELA; MANDOLESI PABLO; COLOMBO OSCAR; CASTRO LILIANA; AGAMENNONI OSVALDO

Lund

Congreso; 17th European Conference on Eye Movements; 2013

Lund University

Reading is an everyday activity requiring the integration of several central cognitive subsystems ranging from attention and oculomotor control to word identification and language comprehension. Several of the associated cognitive processes such as working memory and retrieval memory are known to be impaired in Alzheimer´s disease (AD). This study analyzes eye movement behavior of 18 patients with probable AD and 40 age-matched Controls during Spanish sentence reading. Controls were found to focus on word properties and consider syntactic and semantic structures; effects of word frequency, length, and cloze predictability on reading times indicate local processing of fixated words. Besides, Control?s knowledge about sentence meaning and grammatical structure is quite evident when we consider visual exploration. In the AD group, visual exploration was less focused; fixations were much longer and saccade amplitudes were smaller than in Controls. In addition, the upcoming word predictability effect was absent in the AD group. The altered visual exploration might be related to impairments in working memory and long term memory retrieval functions. These eye movement measures demonstrate considerable sensitivity with respect to evaluating cognitive processes in Alzheimer. They could provide a user-friendly marker of very early disease symptoms and of its posterior progression.