Almost 60 families in the West of Ireland have received apologies in recent weeks for failings in audiology services provided to their children.
It is the second time in less than a year that the HSE has had to apologise for audiology failings.
Last year, an RTÉ Investigates programme revealed serious failings in paediatric audiology services provided to another 49 children in counties Mayo and Roscommon, some of whom were left with lifelong impairments.
The findings were contained in a look-back review of care provided by one audiologist from 2011 to 2015, who no longer works in the Republic of Ireland.
However, it's now emerged that, in recent months, the HSE has written to an additional 57 families to inform them they have also been affected. As before, all these children had attended the same audiologist.
It is understood that the additional 57 cases will now form part of a second look-back review – however, families have not been given any indication as to how long that process will take.
The HSE has explained that the original look-back review related to children aged under four, and it was as part of that process some children aged over four years were also found to have been "discharged from the service without a follow up appointment."
But it says to date "no moderate or major incidents" have been identified.