The beneficial effects of caffeine in reading and global perception

Object: Reading is a unique human skill. Several brain networks - involved in this complex skill - are mainly linked to the left hemisphere language areas. Nevertheless, also non-linguistic networks included in the right hemisphere seem to be involved in sentence and text reading. These areas, which do not contain phonological information, are involved in the verbal and non-verbal pattern information processing. The right hemisphere is responsible for global processing of a scene, which is connected to reading skills. Caffeine seems to directly affect the global pattern processing, consequently, caffeine could enhance text reading skill. Materials In two mechanistic studies, we tested several reading skills, global and local perception, alerting, spatial attention and executive functions as well as rapid automatized naming and phonological memory. Methods: A double-blind, within-subjects, repeated-measures design was used. Results: A single dose of 200 mg of caffeine improved global processing, without any effect on local information processing, alerting, spatial attention, executive and phonological functions. Together with global processing, caffeine improved adults’ text reading speed of meaningful sentences, whereas single word/pseudoword, or pseudoword text reading abilities were not modified. This effect of caffeine on reading ability resulted boosted by small sleep deprivation. Discussion: As already shown in literature, global visual perception and reading skills appear linked together, and caffeine seems to directly improve mechanisms underlying these functions Conclusions: These findings have important implications in understanding the origin, of neurodevelopmental disorders characterized by a global processing dysfunction like developmental dyslexia, attention deficit hyperactivity disorder and autism spectrum disorder.