This unexpected consequence was first reported to the American drugs regulator, the Food and Drug Administration (FDA), last year by one manufacturer of the implants.
The link has now been established in a new study carried out by the National Center on Birth Defects and Developmental Disabilities, which has investigated the records of 4,264 children who were given implants between 1997 and 2002. Of these, 26 had developed bacterial meningitis, something like 30 times the rate that would be expected in a healthy population.
The culprit appears to be the positioner, part of the implant that helps the electrical signal. Children who had an implant with a positioner were four times as likely to develop meningitis as those with an implant without one.
(Source: New England Journal of Medicine, 2003; 349: 535-45).