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Bilateral v Unilateral in young children

Margaret Tait et al:Bilateral versus unilateral implantation in young children

Published in International Journal of Pediatric Otorhinolaryngology 74 (2010) 206–211

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To compare the preverbal communication skills of two groups of young implanted children: those with unilateral implantation and those with bilateral implantation.

Material and methods:

The study looked 69 children: 42 of whom had been unilaterally and 27 bilaterally implanted with age at implantation less than 3 years. The preverbal skills of these children were measured before and 1 year after implantation, using Tait Video Analysis that has been found able to predict later speech outcomes in young implanted children.


Before implantation there was no significant difference between the unilateral group and the bilateral group. Twelve months after implantation there was no difference where vocal autonomy was concerned, but a strongly significant difference between the groups for vocal turn-taking and nonlooking vocal turns, the bilateral group outperforming the unilateral group. With regard to gestural turn-taking and gestural autonomy, there was a strongly significant difference between the two groups at the 12 month interval, and also a difference before implantation for gestural autonomy, the unilateral group having the higher scores. Multiple regression of non-looking vocal turns revealed that 1 year following implantation, bilateral implantation contributed to 51% of the variance (p < 0.0001), after controlling for the influence of age at implantation and length of deafness which did not reach statistical significance.


Profoundly deaf bilaterally implanted children are significantly more likely to use vocalisation to communicate, and to use audition when interacting vocally with an adult, compared with unilaterally implanted children. These results are independent of age at implantation and length of deafness.