Il Braille: aspetti percettivi, linguistici e neurologici della lettura attraverso il tatto

Braille is a writing and reading system used by blind people, which involves the replacement of visual perception of printed characters by tactile interpretation of raised dots. Reading by touch implies the processing of information derived both by movements elicitated by haptic inspection of the stimuli and by propioceptive sources. In this paper, the integration between these perceptive processes and the linguistic ones typical of reading is discussed, with refer to congenitally and late blind people. On one side, particular attention is given to the role of the typology of scanning movements and to the tasks undertaken by the hands (examination of spatial ad linguistic information), on the other to the lexical-semantic processing involved in the decoding phase and to the possible role of previous experiences associated with visual reading. Finally, some data of recent studies examining the relation between Braille reading and neural plasticity are briefly described with particular attention to the involvement and function of the visual cortex in reading by touch.