The effect of implantation age on visual attention skills

Abstract

The aim of this study is to evaluate the visual attention skills of deaf children with cochlear implants and to determine whether age at implantation had any impact on visual attention skills. Thirty children with cochlear implants aged 6 and 11 years were evaluated and were compared with age matched 36 normal hearing children. The children with cochlear implants were analyzed in to two groups according to their age at implantation; under and at/over 4 years old. The Gordon Diagnostic System (GDS) was used in order to evaluate visual attention skills of cochlear implanted (Group 1 and Group 2) and children with normal hearing. The number of correct responses, extraneous button presses (commission errors) and the number of omission errors or the failure to respond to target stimuli which were recorded by GDS was used to evaluate the visual attention skills of the subjects. Also six different types of commission errors (19X, XX9, XX1, X1X, X9X, XXX) were analyzed and compared both for normal and cochlear implant user children. Concerning the total number of correct response, omission and commission errors no statistical difference was found between two implanted groups. Besides, both groups with cochlear implantation differed from normal hearing peers on the total number of correct responses, omission errors (p<0.017). According to these findings cochlear implanted children had less correct responses and had more omission errors compared with control group. These findings clearly show that children with cochlear implants performed poorly on visual attention task which requires constant attention together with the ability to exert impulse control despite they hear enhanced sensory information by cochlear implants. Concerning the types of commission errors Group 1 and 2 performed similarly in all types of errors (p>0.017). Besides, Group 1 and 2 made more errors in types 19X, XX9 and XXX, XX9 compared with the control group (p<0.017). Group 2 who had their implants after age of 4 years old had more commission errors than the control group (p<0.017) and positive correlation was found between the total commission errors and XX9 error type with age at implantation. These findings show that children who had their implants at older ages made more commission errors and XX9 type of commission error. The children who were implanted after 4 years old were less mature; unsuccessful in controlling their impulsive behaviors and more careless where they can not get enough benefit from social and environmental motives compared with their normal hearing peers. This present research points out the positive effect of early implantation on visual attention and the possible adversities such as impulsivity, over-impatience and attention deficits which have been previously suggested as preventive or slowing down factors for the pace of auditory-verbal therapy for cochlear implantees. Assuming that the results of this study support the theory of insufficiency which suggested that the deprivation in auditory system would also adversely affect cognitive structures involved in intermodal processing the importance of early implantation is underlined. If early cochlear implantation will be carried out especially at the very critical period of language development (before age of four), this will help the child, in his/her future life, not only with his/her hearing skills and communication but for his/her attention skills and behavior.