Hereditary deafness in Havanese, while only mentioned recently, is not a new problem. Deaf Havanese have been appearing sporadically for years, but breeders… thinking it was an isolated incident, rarely shared the information. This heritable disorder has a complex mode of inheritance . It is not known at this time whether it is colour/ pattern linked as in other breeds with hereditary deafness.
You cannot check hearing yourself. Most people with unilaterally affected Havanese are completely unaware that a problem exists. Hearing status can be positively ascertained by a Brainstem Auditory Evoked Response test (BAER) which detects electrical activity in the ear and auditory pathways in the brain . It is a very simple test and can be done anytime after a puppy is about 6 weeks old. It is a one time test. The ears should be clean and free of infection, wax build-up and hair overgrowth as these may affect test results.
The test takes approximately 10-15 minutes to complete. Each ear is tested individually. Small ear phones deliver the stimulus and response data is collected through tiny electrodes with the results being displayed on a computer screen. A normal response waveform shows a series of peaks and valleys while the response from a deaf ear is essentially a flat line. Dogs show no evidence of discomfort from the electrodes though they may object slightly to the gentle restraint. Sedation is generally unnecessary in Havanese; even young puppies take the test in stride. At the end of the procedure, the recorded waveform is printed out.
BAER testing can be difficult to locate though is available at veterinary colleges. A test for a single dog may be expensive but prices are substantially lower if done with multiple dogs or at a hearing clinic. Some Veterinary colleges have recently acquired portable equipment which may make BAER clinics more easily accessible in upcoming years. At this time, there appears to be a small number of unilaterally and very few bilaterally affected Havanese, but incidence may rapidly rise as untested unilaterals are bred together. Caution should be exercised when considering breeding known unilateral deaf dogs as the likelihood of deafness may be significantly increased in litters with unilaterally deaf parent(s).
Until a test for this gene mutation is developed, BAER testing breeding stock and puppies prior to placement is one way to help minimize the incidence of deafness in our breed. Please see "BAER 2 - more information" for additional details about it.