Sir, I read the letter 'Cochlear Implants' by S. Harrison1 with great interest. The main function of cochlear implants is to convert the mechanical sound energy into electrical signals.

Since the energy is converted into electrical signals there is a good chance that similar energy may interfere with the proper functioning of the cochlear implants. The author has cited the website which states that the speech processors should be kept at least 50 cm away, and preferably out of the room, when radiographic examinations are undertaken. However on searching the PubMed literature we found at least one paper2 suggesting that panoramic radiographs do not have any adverse effect on the functioning of the cochlear implants. The same paper mentions that electrocautery should be performed cautiously especially at level 7 or above as it destroys the cochlear implant circuits making them non-functional. Young3 also suggested to take precautions in using ultrasonic scalers and electrocautery in such patients. The information presented in the letter cannot be completely relied upon as it is not supported by scientific literature. Also it should be noted that the cochlear implants, which are just another type of nerve stimulator, are also affected adversely by locally given microwave diathermy.4