Are blueeyed dogs deaf?
Deafness in dogs
Deafness is quite common in dogs, particularly in older dogs and dogs with a white hair coat and blue eyes. Although deafness may cause a dog some problems most deaf dogs can be helped to live a happy life.
Why are some dogs deaf?
Deafness is quite common in dogs. Many breeds of dog, e.g. Dalmatians, Collies, Great Danes, English setters and Pointers, carry a gene that can cause deafness. This is often associated with a white or merle coat colour and blue eyes.
Deafness is also common in older dogs, probably due to age-related degeneration in the inner ear, as seen in older people.
Other reasons for deafness are long-term ear infections, growths in the middle ear or external ear canal and medications given by veterinary surgeons to treat these conditions. Head trauma and brain tumours are also potential causes. However, deafness can result from anything that damages the conduction of sound waves from the ear hole through the ear canal and ear drum to the bones of the middle ear or which affects the conduction of impulses through the nerves to the brain.
How would I know if my dog is deaf?
Deafness in one ear is not usually detected and actually causes few problems. If the affected dog is lying on one side with the good ear buried and the deaf one exposed then hearing would be impaired and an owner may notice a lack of response to noises. However, dogs who are deaf in one ear probably take care to avoid lying in such a position and generally keep their good ear pointing in the right direction, even when relaxed at home.
Being deaf in both ears causes more significant problems and most owners notice that their dog does not respond to noises – the opening of doors, the fridge, food packages, calling their name etc. and fail to respond to noisy people, animals and machinery. As puppies, deaf animals may be hard to train and may indulge in very rough play as they are unable to hear protest yelps.
Deaf dogs tend to “sleep well”. This is something that owners of older animals may notice as their pet’s hearing deteriorates with age. Owners of old dogs may notice that they now tolerate the noise of a vacuum cleaner, or fireworks when previously they did not – this may be the most obvious sign of growing deafness.
How would my vet know if my dog was deaf?
Hearing can be tested by observing the reaction the dog makes to a sudden, unexpected loud noise. A hearing dog is expected to turn its ears towards the noise, and may also move their whole head and possibly move their body into a more alert position.
There are problems with this test. It cannot detect deafness in a single ear, only a totally deaf animal will fail to react. It is also possible to think that a deaf animal can hear if, for example, it reacts to a visual clue if it sees an object being dropped or hands being clapped or it may be able to feel vibrations when something hits the floor.
The opposite might also happen – a well-adjusted, non-fearful and relaxed dog may react to a noise the first time it hears it but will quickly react less and less obviously to subsequent noises. This test will be easier to interpret in a dog well known to the owner in its normal environment.
The only truly reliable test is one similar to that used for the testing of hearing in humans and involves sophisticated equipment available only in a few centres. Your veterinary surgeon would be able to advise you of a centre that offers testing if necessary.
The test is well tolerated by most dogs but involves playing noises into each ear in turn and then detecting the nervous impulses invoked by these noises in the brain. It is called BAER (Brainstem Auditory Evoked Response) testing. This test will not be necessary for the vast majority of dogs with a suspected hearing problem as testing will not usually make any difference to the dog or how they are helped and managed.
What problems can deafness cause for my dog?
Dogs with normal hearing use the sounds detected by both ears to accurately pinpoint sounds. A dog that is deaf in one ear may hear you calling when you are out for a walk but may not be able to locate where you are. They may look around wildly until they see your position before coming back.
The reduced ability to recognize danger is probably the most serious handicap faced by totally deaf dogs. A deaf dog cannot hear its owner when out for exercise and so there is a greater risk it will run across a busy road to see a dog on the other side. Further examples of dangerous noisy items are farm and garden machinery, household appliances and trains. Deaf dogs should not be allowed off the lead except in safe, enclosed spaces.
Can deafness be treated?
It is unlikely that there will be a treatment to help resolve the deafness in your pet. The most common causes – a genetic defect or age-related degeneration – have no appropriate treatment. It is only some of the unusual causes such as disease blocking the passage of sound through the external ear canal from infection, or a mass that can be removed by an operation that can be helped by treatment.
Dogs with these conditions will usually have other obvious signs of disease rather than deafness being the major problem. They will have ears that are dirty, smelly and irritating. They may scratch and shake their heads or might also have a head tilt. Other signs of underlying disease include wobbliness, from damage to the balance organs, which are also found in the inner ear.
How can I help my deaf dog?
Animals that are deaf in just one ear require no special treatment. A totally deaf dog can adapt well to living in a normal household. Since your dog cannot hear you, you may need to adopt a more tactile approach with them. Petting and stroking becomes a much more important form of contact when your dog can’t hear you praising it and deaf dogs might want more physical contact, especially when resting in the home to reassure them that you are near (whereas a hearing dog can lie in another room and still be aware of you moving around the house).
Training a dog that has been deaf from birth can be challenging but it is perfectly possible to do this using hand signals for commands. Choose hand signals that are clear and can be recognised from some distance away. ‘Stop’, ‘sit’ and ‘come’ are probably the most useful to teach initially. Dogs are also very good at reading body language so although they cannot hear your voice a deaf dog will be able to tell if you are angry with it or welcoming just by looking at you and it may base its decision on whether to return to you on this impression. It is important as in any dog training to remain calm and positive during training sessions – patience really is the key!
Can I avoid having a deaf dog?
Some dogs are more likely to be deaf so avoid buying puppies from litters where both parents have a merle or harlequin coat. Some puppies from these matings may be born blind as well as deaf.
Conclusion
Deafness causes significant welfare problems and breeders should aim to avoid producing puppies likely to be deaf. However, individual deaf dogs can be given a reasonable quality of life by thinking about their special needs. Deafness (or reduced hearing ability) is also quite common in older dogs and considering this is one aspect of providing a good home for a geriatric companion.
Hearing Loss in Dogs
Deafness refers to the lack (or loss) of an animal’s ability to hear — this can either be complete or partial loss. If the dog is deaf at birth (congenital), it will be very apparent to you at a young age. More than 30 breeds of dogs have a known susceptibility for deafness, including the Australian shepherd, Boston terrier, cocker spaniel, Dalmatian, German shepherd, Jack Russell terrier, Maltese, toy and miniature poodle, and West Highland white terrier. Typically, it is more common in senior dogs.
The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the petMD health library.
Symptoms
- Unresponsive to everyday sounds
- Unresponsive to its name
- Unresponsive to the sounds of squeaky toys
- Not woken by a loud noise
Causes
- Conduction (sound waves do not reach the nerves in the ear)
- Inflammation of the outer ear and other external ear canal disease (e.g., narrowing of the ear canal, presence of tumors, or ruptured ear drum)
- Inflammation of the middle ear
- Nerve
- Degenerative nerve changes in elderly dogs
- Anatomic disorders — poor development (or lack of development) in the part of the ear that contains the nerve receptors used for hearing; the condition leads to fluid buildup in specific areas of the brain and damages the part of the brain involved with hearing
- Tumors or cancer involving the nerves used for hearing
- Inflammatory and infectious diseases — inflammation of the inner ear; canine distemper virus may cause alterations in hearing, but not complete deafness; inflammatory masses that develop in the middle ear or eustachian tube
- Trauma
- Toxins and Drugs
- Antibiotics
- Antiseptics
- Chemotherapy drugs
- Medications to remove excess fluid from the body
- Heavy metals such as arsenic, lead, or mercury
- Miscellaneous — products used to break down waxy material in the ear canal
- Other risk factors
- Long-term (chronic) inflammation of the outer, middle, or inner ear
- Certain genes or white coat color
Diagnosis
A complete history of the dog, including any drugs that may have damaged the ear or caused a chronic ear disease, is completed by the veterinarian. Early age onset usually suggests birth defects (congenital causes) in predisposed breeds. On the other hand, brain disease is a slow progressive disease of the cerebral cortex, usually caused by senility or cancer — making the brain not able to register what the ear can hear. Bacterial cultures and hearing tests, as well as sensitivity testing of the ear canal, may also used to diagnose the underlying condition.
Treatment
Unfortunately, any deafness present in the dog at birth (congenital) is irreversible. If it is caused by an inflammation of the outer, middle, or inner ear, medical or surgical approaches may be used. These two methods, however, are dependent on extent of disease, bacterial cultures, sensitivity test results and X-ray findings. Conduction problems, in which sound waves do not reach the nerves of hearing, may improve as inflammation of the outer or middle ear are resolved. Hearing aids can also sometimes be used for dogs.
Living and Management
Your dog’s activity should be reduced to avoid any any possible injury (e.g., a deaf dog cannot hear an approaching car). The home environment may also need to be controlled for the dog’s protection.
The veterinarian will need to see your dog weekly and treat it for the ear disease, or until the condition is resolved.
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Congenital sensorineural deafness in cats
Congenital sensorineural deafness occurs commonly in domestic cats with a white coat. It is a congenital deafness caused by a degeneration of the inner ear. [1] Deafness is far more common in white cats than in those with other coat colours. According to the ASPCA Complete Guide to Cats, «17 to 20 percent of white cats with nonblue eyes are deaf; 40 percent of «odd-eyed» white cats with one blue eye are deaf; and 65 to 85 percent of blue-eyed white cats are deaf.» [2]
Charles Darwin mentions this phenomenon in his book, On the Origin of Species, to explain correlated variation. [3]
Domesticated cats with blue eyes and white coats are often completely deaf. [4] Deafness can occur in white cats with yellow, green or blue irises, although it is mostly likely in white cats with blue irises. [5] In white cats with mixed-coloured eyes (odd-eyed cats), it has been found that deafness is more likely to affect the ear on the blue-eyed side. [1] White cats can have blue, gold, green or copper coloured odd eyes.
In one 1997 study of white cats, 72% of the animals were found to be totally deaf. The entire organ of Corti in the cochlea was found to have degenerated in the first few weeks after birth; however, even during these weeks no brain stem responses could be evoked by auditory stimuli, suggesting that these animals had never experienced any auditory sensations. It was found that some months after the organ of Corti had degenerated, the spiral ganglion of the cochlea also began to degenerate. [6]
Genetics [ edit ]
Although few studies have been done to link this to genes known to be involved in human Waardenburg syndrome, a syndrome of hearing loss and depigmentation caused by a genetic disruption to neural crest cell development, such a disruption would lead to this presentation in cats as well. [7] Waardenburg syndrome type 2A (caused by a mutation in MITF) has been found in many other small mammals including dogs, minks and mice, and they all display at least patchy white depigmentation and some degeneration of the cochlea and saccule, as in deaf white cats. [8] [9]
A major gene that causes a cat to have a white coat is a dominant masking gene, an allele of KIT which suppresses pigmentation and hearing. The cat would have an underlying coat colour and pattern, but when the dominant white gene is present, that pattern will not be expressed, and the cat will be deaf. A cat that is homozygous (WW) or heterozygous (Ww) for this gene will have a white coat despite the underlying pattern/colour. A cat that lacks this dominant masking gene (ww) will exhibit a coat colour/pattern. [10] KIT mutations have also led to patchy depigmentation and different coloured irises in humans, [11] and KIT has been found to increase MITF expression, the gene involved in human Waardenburg syndrome type 2A. [12]
A white cat may have blue eyes for reasons other than masking. If the underlying coat pattern is one of a pointed cat (also referred to as a Siamese pattern), the blue eyes may come from the genetics of the pointed gene.
A common misconception is that all white cats with blue eyes are deaf. [13] It is possible to have a cat with a naturally white coat without this gene, as an extreme form of white spotting, although this is rare – some small non-white patch usually remains.
In popular culture [ edit ]
- The character Snowkit in A Dangerous Path has congenital sensorineural deafness. [14] His condition leads to his death as he fails to hear his mother’s warning of the appearance of a predator. [15]
See also [ edit ]
- Cat coat genetics
- Merle (dog coat)
- Pleiotropy
- Van cat
- Waardenburg syndrome
References [ edit ]
- ^ ab Bosher, SK; Hallpike, CS (13 April 1965). «Observations on the histological features, development and pathogenesis of the inner ear degeneration of the deaf white cat». Proceedings of the Royal Society B: Biological Sciences. 162 (987): 147–170. Bibcode:1965RSPSB.162..147B. doi:10.1098/rspb.1965.0030. PMID14285813. S2CID36675534.
- ^
- Richards J (1999). ASPCA Complete Guide to Cats: Everything You Need to Know About Choosing and Caring for Your Pet. Chronicle Books. p. 71. ISBN9780811819299 .
- ^
- Charles Darwin (1909). On The Origins Of Species. p. 13. ISBN9788187572664 .
- ^
- Webb AA, Cullen CL (June 2010). «Coat color and coat color pattern-related neurologic and neuro-ophthalmic diseases». Can. Vet. J. 51 (6): 653–7. PMC2871368 . PMID20808581.
- ^
- «Ask Elizabeth: White Cats and Blindness/Deafness». Cornell University College of Veterinary Medicine. Cornell University College of Veterinary Medicine Ithaca, New York . Retrieved 3 December 2016 .
- ^
- Heid, S; Hartmann, R; Klinke, R (January 1998). «A model for prelingual deafness, the congenitally deaf white cat—population statistics and degenerative changes». Hearing Research. 115 (1–2): 101–12. doi:10.1016/S0378-5955(97)00182-2. PMID9472739. S2CID38262220.
- ^
- Omenn, Gilbert S.; McKusick, Victor A.; Gorlin, Robert J. (1979). «The association of Waardenburg syndrome and Hirschsprung megacolon». American Journal of Medical Genetics. 3 (3): 217–223. doi:10.1002/ajmg.1320030302. ISSN1096-8628. PMID484594.
- ^
- MARKAKIS, MARIOS N.; SOEDRING, VIBEKE E.; DANTZER, VIBEKE; CHRISTENSEN, KNUD; ANISTOROAEI, RAZVAN (2014-08-01). «Association of MITF gene with hearing and pigmentation phenotype in Hedlund white American mink (Neovison vison)». Journal of Genetics. 93 (2): 477–481. doi:10.1007/s12041-014-0370-3. hdl: 10067/1211550151162165141 . ISSN0973-7731. PMID25189243. S2CID16725018.
- ^
- Strain, George M. (2015). «The Genetics of Deafness in Domestic Animals». Frontiers in Veterinary Science. 2: 29. doi: 10.3389/fvets.2015.00029 . ISSN2297-1769. PMC4672198 . PMID26664958.
- ^
- David, Victor A.; Menotti-Raymond, Marilyn; Wallace, Andrea Coots; Roelke, Melody; Kehler, James; Leighty, Robert; Eizirik, Eduardo; Hannah, Steven S.; Nelson, George; Schäffer, Alejandro A.; Connelly, Catherine J. (2014-10-01). «Endogenous Retrovirus Insertion in the KIT Oncogene Determines White and White spotting in Domestic Cats». G3: Genes, Genomes, Genetics. 4 (10): 1881–1891. doi:10.1534/g3.114.013425. ISSN2160-1836. PMC4199695 . PMID25085922.
- ^
- Hamadah, Issam; Chisti, Muzamil; Haider, Mansoor; Al Dosssari, Haya; Alhumaidan, Rawan; Meyer, Brian F.; Wakil, Salma M. (2019-07-13). «A novel KIT mutation in a family with expanded syndrome of piebaldism». JAAD Case Reports. 5 (7): 627–631. doi:10.1016/j.jdcr.2019.01.021. ISSN2352-5126. PMC6630042 . PMID31341943.
- ^
- Lee, Youl-Nam; Brandal, Stephanie; Noel, Pierre; Wentzel, Erik; Mendell, Joshua T.; McDevitt, Michael A.; Kapur, Reuben; Carter, Melody; Metcalfe, Dean D.; Takemoto, Clifford M. (2011-03-31). «KIT signaling regulates MITF expression through miRNAs in normal and malignant mast cell proliferation». Blood. 117 (13): 3629–3640. doi:10.1182/blood-2010-07-293548. ISSN0006-4971. PMC3072881 . PMID21273305.
- ^
- George M. Strain (2011). Deafness in Dogs and Cats. CABI. pp. 68. ISBN978-1-84593-764-5 .
- ^
- Hunter, Erin (17 March 2015). A Dangerous Path. Harper Children’s. p. 79-81. ISBN9780062367006 .
- ^
- Hunter, Erin (17 March 2015). A Dangerous Path. Harper Children’s. p. 94. ISBN9780062367006 .
