hearing tests for mentally retarded and psychotic people

[Hollytree]

Does anyone on this group know of recommendations for hearing screening in
institutionalized mentally retarded and mentally ill individuals?  I believe
that the incidence of hearing loss is greater in these groups and that their
ability to report it is less.  I also believe that lack of diagnosis is more
serious and may interfere with ability to communicate, resulting in increased
loss of freedom, unnecessary medications etc.  I would be interested in any
hard information to support this belief.  Would appreciate responses in email
if possible.