Scientists believe the procedure is largely ineffective on children over the age of two because their brains have already adapted to total deafness.
Thanks to donors - including a £30,000 mystery donation - the couple raised the money in time, giving the go-ahead for surgeons to fit 19-month-old Oliver with a special electronic device to stimulate his brain stem.
Last month they were able to travel to the University of Verona Hospital so Oliver could be operated on by top surgeon Vittorio Colletti, whose research helped develop the groundbreaking procedure.
Oliver's family was thrilled when the device - known as an auditory brainstem implant - was switched on and Oliver instantly reacted to the sound of a banging drum.
Mrs Bosch, 37, from Dundee, said: 'It has been a real race against time to raise this money and we're just so relieved we've managed to do it.
'It was very emotional when the implant was switched on and Oliver reacted to the sound of the drum.
'Both Ben and I promised each other that we would try not to cry and we just about managed to hold it together.
'We've been on quite a journey and we both know that if we'd waited just a few more months it could have been a different story as it might not have worked.
'It is a long road ahead and we still need to raise thousands more for all the speech therapy he'll need.
Read more:
Parents' joy as baby born deaf hears for the first time after pioneering surgery - paid for by £60,000 of donations | Mail Online
