Auditory Working Memory Capacity in Congenitally Blind Children: Comparative Study with Normal

Abstract

to these studies, there have been many studies have found no added advantage for blind individuals [11-16]. It is a well-known fact that the occipital lobe gets activated when processing visual stimuli in normal healthy sighted individuals. In blind individuals it has been found that it is active during verbal processing [17] and performance of memory tasks [7,18]. These results suggest that the advantages found in the be-havioural tests may rely on cross-modal plasticity that enables visual areas to encode stimuli and tasks of other modalities in early blind individuals. Recent studies found that congenitally blind and early blind subjects perform better than late-blind subjects and normal on several auditory perception task [19-21]. These studies point to the plasticity of the sensory systems when an individual is confronted with the loss of a particular modality. However, these studies do not inform us about the use and plasticity of the working memory system, but only about the in-teresting possibility of plasticity of one of the components, i.e., the visuospatial sketch pad that might be replaced by another sensory modality. Congenitally blind individuals have been shown to compensate for their loss of sight by developing extraordinary abilities in their remaining senses. An ongoing debate regarding whether blind individuals can compensate for their sensory handicap by developing exceptional abilities in their remaining senses (com-pensatory hypothesis), or by becoming severely handicapped (the deficit hypothesis) has yielded contrasting positions. Owing to such findings the present study was designed to assess the au ditory memory abilities in congenitally blind children to throw a light on the research concerning the compensation for the loss of sight through other normal modality information and to comment on the plasticity of working memory system in blind.