Dalmatians are susceptible to hereditary deafness.
This is not the deafness that can occur from old age, but a deafness that occurs when the puppy is about 15days old. It can not be reversed.
 
In layman's terms the genes that are responsible for the white coat on the Dalmatian are also thought to be responsible for the minute hairs that line the middle ear. These hairs are responsible for carrying the movement of sound waves and sending signals to the brain.
 
This is why many white coated breeds have also been found to have problems with hereditary deafness.
 
Previously, it had been thought that a Dalmatian was either totally deaf  - BILATERALLY DEAF or totally hearing - BILATERALLY HEARING, but the development of an electronic test called the BAER hearing test;

BRAINSTEM AUDITORY EVOKED RESPONSE

………Was able to show that a Dalmatian could also be deaf in one ear - UNILATERAL DEAFNESS. 
Before this, a unilateral deaf dog had been extremely difficult to diagnose.  As dogs already have hearing which is hundreds of times better than human hearing, the dog was able to respond to sounds from just one ear extremely well.
 
Totally deaf dogs had already been removed from any breeding programmes, but now it was realized that a unilateral dog should also be removed from any breeding programmes as it was found they carried the same defective gene as a totally deaf dog.
Breeding from either a Bilateral or Unilateral deaf dog will significantly increase the chances of totally Bilaterally deaf puppies.
 
Most conscientious breeders today are now only using parents with Bilateral hearing, and gradually the hearing test result of litters is starting to improve.
It is believed that we will never eliminate deafness from our breed totally but it is hoped that one day a genetic test will be available to identify carriers.
 
Hearing tests carried out by breeders or vets, by making noises to see if there is any response, is NOT accurate enough, NOR does it identify Unilaterals.
The puppy or indeed parents must be BAER hearing tested.
(A limited number of testing machines are in the country with trained professionals using them)
 
 

It is vital that you check that your new puppy has been BAER hearing tested. Should you be looking to buy a Dalmatian for use in future breeding, it is vital that its parents are Bilaterally hearing (in fact the more generations the better).
 
Unilaterally deaf puppies make excellent pets. They are just as easily trained, and although a slight difficulty on locating the source of a sound may be found, the majority of Unilaterals are unrecognizable as such.
However, as mentioned Unilaterals should not be bred from.
A good breeder will either have a contract with the new owner, that the puppy will be neutered at an appropriate age or have an endorsement on the pedigree - 'not to be bred from'.
 
Totally deaf puppies are an extremely difficult prospect. Particularly as Dalmatians are such a lively breed.
A totally deaf puppy would need to be taught hand signals. It would need to learn to always be looking at the owner when off the lead.  It would have to be very carefully watched that an approaching dog or human did not 'catch it unawares', which could result in a fright and a snap.
Whilst some quieter breeds may be able to cope with a life like this, a Dalmatian can be extremely difficult.
 
I would recommend that the average pet owner should not accept a totally deaf Dalmatian.  They need a very experienced and specialist home.
Many totally deaf Dalmatians end up being re-homed or in rescue.