chloelogoa

          DEAFNESS IN DOGS          

talalogoa

What is Deafness
What is Congenital Deafness and Vestibular Disease
About Deaf Dogs
Hand Signals for Dogs
Congenital Deafness and its Recognition
Training your Deaf Dog
Why Should Deaf Dogs be Victimised?
Pet Pager

ciddlogo  

What is deafness?










Inherited deafness in one or both ears occurs due to the degeneration of sensory inner ear structures (sensorineural deafness) within a few weeks of birth. This occurs in many breeds and is especially common in the dalmatian.

The trait for deafness is tied to the genetics of coat colour, particularly in breeds with the merle or piebald gene. There is an increased risk of deafness with increasing amounts of white in the coat.

How is deafness inherited?
The mode of inheritance in dalmatians is thought to be autosomal recessive involving more than 1 gene (or incomplete penetrance may be involved), since dogs with normal hearing in both ears can produce bilaterally deaf puppies, and vice versa. Dogs with deafness in 1 ear can have pups that are deaf in both or neither. Statistically however, deaf parents are more likely to produce deaf pups.

Dogs with an increased amount of white in their coats and blue eyes (discussed further below) are predisposed to congenital deafness. In breeds in which deafness is associated with merle colour, the trait appears to be autosomal dominant.

In the bull terrier, Doberman pinscher, pointer and rottweiler, congenital deafness is thought to be an autosomal recessive trait.

What breeds are affected by deafness?
Deafness occurs in many breeds. The highest incidence is in the dalmatian, with studies from the US and the UK showing that 18 to 30% are unilaterally deaf, and 5 to 10% are bilaterally deaf. The condition is slightly more common in female dalmatians. Other breeds with a relatively high incidence of deafness are the English setter, Australian shepherd, border collie and Shetland sheepdog.

There is a strong association of deafness with increased amounts of white colour in the coat and blue eyes (heterochromia iridis) in breeds with merle and piebald coat colouring. Merled breeds include the merled collie and Shetland sheepdog, Australian heeler, dapple dachshund (18% bilaterally deaf, 36% unilaterally deaf), harlequin great Dane, Norwegian dunkerhound, and old English sheepdog. Breeds with the piebald gene (which affects the amount and distribution of white areas) include the beagle, bull terrier, samoyed, great Pyrenees, Sealyham terrier, greyhound, English bulldog, English setter, and of course dalmatian.

Congenital deafness is reported less commonly in many other breeds including the akita, cocker spaniel, Staffordshire terrier, Boston terrier, boxer, Catahoula leopard dog, Doberman pinscher, dogo Argentina, English springer spaniel, foxhound, German shepherd, greyhound, Jack Russell terrier, Kuvasz, Maltese terrier, miniature pinscher, miniature and toy poodle, papillon, Rhodesian ridgeback, rottweiler, St. Bernard, Scottish terrier, Shropshire terrier, Siberian husky, Walker American foxhound, West Highland white terrier, whippet.

For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

What does deafness mean to your dog & you?
Pups lose their hearing a few to several weeks after birth. Signs of bilateral deafness may include aggressive play because the deaf pup does not hear cries of pain from littermates, and having to be jostled to waken. Unilateral deafness is much harder to spot.

If your dog is deaf in only 1 ear, you will likely not even be aware of it. In training sessions, you may notice that your dog responds better to hand signals than verbal cues.

One-sided deafness is generally not a problem, except in some working dogs for whom localization of sound is important. However it is much more difficult for bilaterally deaf dogs to lead a normal life, and breeders will generally opt for euthanasia of these pups.

How is deafness diagnosed?
If you suspect your dog is deaf, your veterinarian will recommend the BAER (Brainstem Auditory-Evoked Response) test since hearing loss can be very difficult to evaluate by clinical examination (ie. behavioural response to sounds). The BAER test is a painless and reliable means of detecting hearing loss in one or both ears, that is available at veterinary schools and referral centres. It can be used in puppies of 5 weeks of age on. Older pups and adult dogs may need to be sedated for the test.

Dogs in breeds with a high incidence of deafness should be tested by the BAER test before being used for breeding, and pups should be tested before being sold. Hearing loss, if present, is complete - that is the dog either has normal hearing, or is totally deaf in 1 or both ears.

How is deafness treated?
Deafness can not be cured or treated, but dogs can generally accommodate very well, particularly if only deaf in 1 ear. They should not be bred.

Because dogs that are deaf in both ears startle easily, are difficult to train, and are prone to accidents, they are usually euthanized as pups. As an alternative, an owner may train the dog to respond to hand signals or other visual cues, always restrain him/her on a leash or in a fenced yard, and be alert to the possibility of the dog biting someone if startled.

Breeding advice
Controlled breeding can reduce deafness. Any dalmatian to be used for breeding should be checked by the BAER test. Pre-breeding BAER screening should also be used in other breeds where congenital deafness is a problem. Bear in mind that dogs who are deaf in 1 ear appear to function normally, but they should not be used for breeding as this contributes to the perpetuation of this disease.

There is a lower incidence of deafness in dalmatians in Norway and the UK, likely due to selection by breeders against blue eyes, which are considered a desireable feature in the US.

Well-defined and publicized screening programmes and registries of dogs used for breeding will help to reduce the incidence of deafness. The Institute for Genetic Disease Control in Animals maintains an open registry for deafness, for all breeds. http://www.vetmed.ucdavis.edu/gdc/gdc.html

It is laudable that dalmatian breed clubs, particularly in the UK, have supported research aimed at reducing deafness through assistance with funding and data collection.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources
Ackerman, L. 1999. The Genetic Condition: A Guide to Health Problems in Purebred Dogs. pp 132-133. AAHA Press. Lakewood, Colorado. This reference has a good explanation of the heredity of the deafness trait and the association with merle and piebald coat colours.
Wood, J.L.N., Delauche, A.J., Lakhani, L.H. 1996. The problem of inherited disease 6: deafness in Dalmatians. J. of Small Animal Practice. 37(11) : 559-561.
Copyright © 1998 Canine Inherited Disorders Database. All rights reserved. Revised: October 30, 2001.
This database is funded jointly by the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary College, University of Prince Edward Island, and the Canadian Veterinary Medical Association.

reprinted with kind permission from:- Alice Crook, DVM,Coordinator, Sir James Dunn Animal Welfare Centre, Atlantic Veterinary College,University of Prince Edward Island, 550 University Ave.Charlottetown, PEI C1A 4P3
http://www.upei.ca/cidd


back to top

****************************



ciddlogo  

What is congenital deafness and vestibular disease?

http://www.upei.ca/cidd

related terms: congenital peripheral vestibular disease
The vestibule is an oval cavity in the inner ear containing tiny bones (bony labyrinth) and sensory cells that affect locomotion and are part of the hearing system. In dogs with this condition, some of these structures begin to degenerate shortly after birth. Affected dogs show early signs of a vestibular deficit (eg. a head tilt, lack of coordination, and circling) and become completely deaf by about 3 weeks of age, although this is often not noticed until later.

How is congenital deafness and vestibular disease inherited?
This disorder has been most studied in the Doberman pinscher, in which it is believed to be an autosomal recessive trait.

What breeds are affected by congenital deafness and vestibular disease?
Doberman pinscher. Deafness with vestibular signs is also reported in the beagle, Akita, English cocker spaniel, German shepherd dog, Shetland sheepdog, and Tibetan terrier.

For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

What does congenital deafness and vestibular disease mean to your dog & you?
Although affected puppies are lively and alert, owners or breeders will usually see signs such as a head tilt, circling behaviour, or a tendency to roll over or fall by 10 to 16 weeks of age. Pups lose their hearing a few to several weeks after birth. Signs of bilateral deafness may include aggressive play because the deaf pup does not hear cries of pain from littermates, and having to be jostled to waken. 

The clinical signs such as circling, head tilt, and lack of coordination usually improve with age. This is a result of compensation by other parts of the brain. However specific tests show that the underlying vestibular deficit remains the same.

Deafness is permanent. Although dogs can accommodate remarkably well in familiar surroundings, dogs that are deaf in both ears startle easily, are difficult to train, and are prone to accidents. For these reasons, they are usually euthanized as pups if the condition is recognized early. As an alternative, an owner may train the dog to respond to hand signals or other visual cues, always restrain him/her on a leash or in a fenced yard, and be alert to the possibility of the dog biting someone if startled.

How is congenital deafness and vestibular disease diagnosed?
The clinical signs (head tilt, circling, etc.) point to a vestibular deficit. Your veterinarian will do blood tests to rule out various possible causes, since this particular disorder is fairly rare. A BAER (Brainstem Auditory-Evoked Response) test is required to evaluate hearing, as hearing loss can be very difficult to assess by clinical examination (ie. behavioural response to sounds). The BAER test is a painless and reliable means of detecting hearing loss in one or both ears, that is available at veterinary schools and referral centres. It can be used in puppies of 5 weeks of age on. Older pups and adult dogs may need to be sedated for the test.

How is congenital deafness and vestibular disease treated?
There is no treatment or cure. The clinical signs of a vestibular deficit are likely to improve with age; deafness is permanent.

Breeding advice
Although little is known of the inheritance of this condition in breeds other than the doberman, affected dogs should definitely not be bred. It is preferable not to breed their close relatives (parents or siblings) either.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources
Wilkes, M.K., Palmer, A.C. 1992. Congenital deafness and vestibular deficit in the doberman. J. of Small Animal Practice. 33: 218-224. This reference has detailed information on the pathological changes seen with this disorder.
Copyright © 1998 Canine Inherited Disorders Database. All rights reserved.Revised: October 30, 2001.
This database is a joint initiative of the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary College, University of Prince Edward Island, and the Canadian Veterinary Medical Association.
reprinted with kind permission from:- Alice Crook, DVM,Coordinator, Sir James Dunn Animal Welfare Centre, Atlantic Veterinary College,University of Prince Edward Island, 550 University Ave.Charlottetown, PEI C1A 4P3
http://www.upei.ca/cidd

back to top

*******************

About Deaf Dogs

http://www.dfordog.com

Dogs that cannot hear are quite often written off as too difficult to train, unable to recall or be let off lead and generally unable to live a ‘normal’ life. But a deaf dog only has one of the five senses missing and can accommodate for this loss much better than you might imagine. With their heightened sense of smell and eager eyes, a deaf dog can understand, interact and learn just as well as their hearing companions. With a little time and imagination from their owners, a deaf dog can learn all the behaviours that a hearing dog can, including recall.

Deaf Dog Hand Signals
The key to a ‘normal’ relationship with your deaf dog is to substitute the spoken word for some hand signals. Some people learn commands from UK or USA sign language standards. Alternatively, you can make up your own signs to suit you and your dog. Have some fun and be inventive but bear in mind that all signs should be clear, easily distinguishable from other signs and preferably even performed away from your body so that your sign is clearly visible to your dog. For this reason, by all means look up some official signs but do adapt them to your own needs, or change them completely into something that you can easily remember. We made up many signs for our deaf dog, Berkeley. Only a few of them are large and away from the body such as the recall sign. Most are more discrete as Berkeley is very observant and also rather frightened of large sweeping hand movements. See how you get on and don’t be afraid to adapt your signs to your own dog’s needs.

Using Sign Language with a Deaf Dog
Whatever signs you choose, be consistent. Make a note of the signs you intend to use and maybe draw them out. Put them on the fridge door or somewhere easy to view and stick to those signs.

Start to use your signs exactly as you would normally speak to a hearing dog. Start with some everyday pleasant events such as a sign for ‘dinner time’ and a sign for ‘walkies’. These are two activities that most dogs love. So, for example, get your dog’s attention with a gentle tap near the shoulder blades and sign for ‘dinner’ and then put the food bowl down or sign for ‘walkies’ and immediately get the dog lead off it’s hook. You will be amazed at how quickly your deaf dog will come to associate the sign with the event that follows. Keep using your chosen sign and watch your dog’s reaction. If they respond with excitement and prepare for walkies or dinner then you have successfully communicated to your deaf dog. Congratulations.

You will be surprised how the rest of the signs will follow easily. Your deaf dog soon learns that your hands and movements are telling them interesting things.

Speak as you Sign
It is always a good idea, when signing, to also speak to your dog. If you are signing something happy such as ‘walkies’, it helps if you are smiling as you sign. As you sign ‘walkies’ also say ‘walkies’ and this will show in your face. Dogs are experts at reading body language, including facial expressions. The sign will be learnt quicker and have more meaning to your dog. Of course, the same goes for naughty signs such as ‘no’. Perform your sign for ‘no’ but also say ‘no’ at the same time, which will help you to convey your meaning.

Training a Deaf Dog with Hand Signals
Now you are in the swing of using your hand signals consistently and for everyday activities, you can begin some basic training. Remember, we are training a dog, it just happens to be a deaf dog. The basic rule is to train the same way you would train a hearing dog but add hand signals to your verbal commands. It is important to remember this. All the usual rules of good basic dog training apply*.

Training a deaf dog is not really that different to training a hearing dog. At most it will involve a little more time and patience, but it is possible and deafness is not ever an excuse for a poorly behaved, under trained pooch.

Good Basic Dog Training:
Train your dog using whatever motivates them, be it a food treat or a favourite toy. Keep training sessions short (5-10 mins per session) and always end training sessions on a positive note such as an easy trick that you know your dog can perform. Never shout or loose your temper and never train if you or your dog is tired or getting bored. Always use positive training methods as you will get much better results and your pooch will thank you for it.

This article is strictly copyright to D for Dog © www.dfordog.com
Any part of this article can only be replicated or used with our express permission or by clearly crediting D for Dog and linking to us.
 
********************************
back to top

Hand Signals For Deaf

© www.dfordog.com
http://www.dfordog.com

handsignals1
handsignals2
handsignals3
To get their attention
Lie down
Come here
handsignals4
handsignals5
handsignals6
Stay
Go in the garden / do a wee

Walkies
handsignals7
handsignals8
handsignals9
I'm going out
(without you)
Lets play / Get your toy
Drop
handsignals10
handsignals11
handsignals12
Get down
Bring it to me
Eat / Dinner time
handsignals13
handsignals14
handsignals15
No / Naughty / Stop it
Someone is at the door
Sit
handsignals16
handsignals17

Quiet / Calm down
All done / Finished


**************************

Veterinary Clinics of North America: Small Animal Practice - Special Issue: Pediatrics - July, 1999


Congenital Deafness and Its Recognition

George M. Strain, PhD
Professor of Neuroscience, Veterinary Physiology, Pharmacology and Toxicology, School of Veterinary Medicine; and Associate Vice Chancellor, Office of Research and Graduate Studies, Louisiana State University, Baton Rouge, Louisiana, 70803

This work was supported by Grant No. 1R15DC01128-01 from the National Institutes of Health and by a grant from the American Kennel Club.

Synopsis
Congenital deafness in dogs and cats is primarily of the hereditary sensorineural form associated with white pigmentation genes, although acquired forms of deafness are possible. Highest prevalence is seen in white cats, especially those with blue eyes, and the Dalmatian, with many other dog breeds affected to some extent. This deafness results from degeneration of the cochlear blood supply at age 3 to 4 weeks, presumably resulting from suppression of melanocytes by the white (cat) or merle or piebald (dog) genes. Mechanism of inheritance is not understood for most breeds. Such animals should not be bred and may present liabilities for their owners. Objective diagnosis of deafness, especially when unilateral, relies on the brain stem auditory evoked response, an electrodiagnostic test where electrical activity in response to a click stimulus is recorded from the scalp using needle electrodes and a special purpose computer. Client counseling guidelines are presented.

Sensory function in neonatal dogs and cats is primarily tactile, olfactory and gustatory. The visual and auditory senses, although partially functional at birth, exhibit significant postnatal development: in the dog, the eyes do not open until a puppy is 8 to 10 days of age, the ear canals do not open until it is 12 to 13 days of age, and mature system function up through the cortex is not present until it is 3 months of age or older.(18,22) Similar delays are seen in the cat. As a result, disorders of these systems frequently escape early detection.

Deafness can be described as (1) congenital or late onset, (2) hereditary or acquired, and (3) conductive or sensorineural.(14,15) The most commonly occurring deafness forms in dogs and cats are congenital hereditary sensorineural deafness, late onset acquired sensorineural deafness, and late onset acquired conductive deafness. Distinguishing between hereditary and acquired deafness is generally not possible without breeding trials, although an assumption of hereditary deafness can be made in breeds with a high prevalence of deafness. The most common form of deafness in young dogs and cats is congenital hereditary sensorineural deafness, with acquired conductive and acquired sensorineural appearing on rare occasions.

PATHOPHYSIOLOGY OF DEAFNESS
Perception of sound first requires transmission through the outer and middle ears to the cochlea for transduction by neural hair cells. Perception results from (1) transmission of transduced auditory information from the cochlea by the eighth cranial nerve to the dorsal and ventral cochlear nuclei, the inferior colliculus, the medial geniculate nucleus of the thalamus, and the primary and secondary cortical auditory areas on the temporal lobe; and (2) attention to the arriving information. Commingling of ipsilateral and contralateral auditory information occurs at multiple steps in the ascent up the auditory pathway. As a result, unilateral hearing loss rarely results from lesions or disease affecting auditory structures above the eighth nerve. Central deafness (unilateral or bilateral) in the absence of severe neurologic disease is clinically unknown in veterinary medicine and is not considered further here.

Conduction Deafness
Conduction deafness results from blockage of sound transmission to the cochlea as a consequence of occlusion of the ear canal or middle ear cavity, or from developmental defects. Occlusion may result from excess cerumen production, from otitis externa or media, or from foreign objects. Developmental defects, which are uncommon, may include atresia of the tympanum or ossicles, fusion of the ossicles, or collapse of the ear canal from cartilaginous weakness or incomplete development. Conduction deafness may be partial or complete and may be reduced by intervention in some cases. Clearance by the body of the mucopurulent discharge and detritus from otitis media may require weeks to months after termination of the infection; hence, recovery of auditory function is delayed. Hereditary forms of conduction deafness have not been identified in domestic species, but the appearance of such a disorder from a spontaneous genetic defect is possible.

Congenital Acquired Sensorineural Deafness
Congenital acquired sensorineural deafness, which is uncommon, can result from in utero or perinatal exposure to ototoxic compounds such as maternal treatment with aminoglycoside antibiotics,21 in utero or perinatal otitis or meningitis, anoxia, or even trauma. Breeders with animals belonging to breeds with a high prevalence of hereditary sensorineural deafness may suggest acquired causes of deafness rather than confront the breeding and other implications of the presence of a hereditary disorder. Sensorineural deafness, whether hereditary or acquired, is the consequence of cochlear hair cell loss through primary or secondary mechanisms (see below).

Congenital Hereditary Sensorineural Deafness

deafness1
Figure 1. Cross-section of the cochlea. The organ of Corti rests on the basilar membrane, with its hair cell cilia embedded in the tectorial membrane. The stria vascularis on the outer margin of the scala media secretes the endocochlear fluid of the scala media and maintains a high K+ concentration essential to sound transduction by the hair cells. Sensorineural deafness can result from primary or secondary loss of cochlear hair cells. (From Bloom W, Fawcett DW: A Textbook of Histology, ed 10. Philadelphia: WB Saunders, 1975; with permission.)



Congenital hereditary sensorineural deafness is usually seen in dog and cat breeds with white pigmentation. In the small number of canine breeds where it is not associated with white pigmentation (Doberman and other dog breeds not carrying piebald or merle genes),23 deafness results from the type of hair cell loss that is a primary event with unknown cause. In breeds of dogs carrying the piebald or merle genes and breeds of cats carrying the white gene, the hair cell loss is secondary to degeneration of the cochlear blood supply. Figure 1 shows a cross section of one turn of the cochlea, demonstrating the separation of the cochlea into three parallel ducts: the scala vestibuli, the scala media (or cochlear duct), and the scala tympani which joins at the apex of the cochlea with the scala vestibuli. The outer margin of the scala media is covered by a vascular bed, the stria vascularis. The stria is responsible for secretion of endocochlear fluid and maintenance of its high K+ concentration which is essential to sound transduction by the sensory hair cells. In pigment-associated hereditary deafness, this vascular bed degenerates, resulting in secondary loss of hair cells and deafness. The cause for the strial degeneration is unknown, but histologic studies have demonstrated an absence of strial melanocytes, whose presence or postnatal development is suppressed by the piebald or merle genes. The function of melanocytes in the stria is unknown, but they appear to be critical to maintenance of elevated K+ levels in the scala media and survival of the stria. Whether hair cell death is from primary or secondary mechanisms, the loss is permanent, as mammals are unable to regenerate cochlear neuronal tissue.

In the Dalmatian, postnatal auditory function development has been shown to proceed normally up until 3 weeks of age, at which point the strial degeneration produces rapid loss of hair cell function.6 A similar time course is likely in other breeds of dogs and cats with pigment-associated deafness, but it has not been studied. Likewise, the time course of congenital deafness in canine breeds not associated with white pigmentation has not been documented, but it is likely that deafness is present at birth or shortly thereafter. As a consequence of the documented 3 to 4 weeks of age at which time deafness appears, hearing testing, as described below, is typically not performed until an animal reaches at least 5 weeks of age.

Table 1. Breeds With Reported Congenital Deafness
Akita
Doberman Pinscher
Papillon
American-Canadian Shepherd
Dalmatian
Puli
American Eskimo
Dappled Dachshund
Rottweiler
American Staffordshire Terrier
Dogo Argentino
 Rhodesian Ridgeback
 

Australian Cattle Dog
English Bulldog
Saint Bernard
Australian Shepherd
English Bulldog
Schnauzer
Beagle Fox Terrier
English Cocker Spaniel
Scottish Terrier
Bichon Frise
English Setter
Sealyham Terrier
Border Collie
French Bulldog
 Shetland Sheepdog
Borzoi
 Foxhound
Shropshire Terrier
Boston Terrier
German Shepherd
 
Sussex Spaniel

Boxer Ibizan Hound
Great Dane
Maltese Tibetan Spaniel
Bulldog
Great Pyrenees
Siberian Husky
Bull Terrier
Jack Russell
Soft Coated Wheaten Terrier

Cardigan Welsh Corgi
Kuvasz Springer Spaniel
Tibetan Terrier
Catahoula Leopard Dog
 Labrador Retriever
Toy Poodle
Cavalier King Charles
Miniature Poodle
Walker American Foxhound
Chihuahua Miniature Pinscher
mongrel
 West Highland White Terrier
Chow Chow
Nova Scotia Duck Tolling Retriever
 Whippet
Cocker Spaniel
Pit Bull Terrier
Old English Sheepdog
Collie Norwegian Dunkerhound
Pointer
Italian Greyhound

A wide variety of breeds of dogs have been reported to have congenital deafness (see Table 1); not all of these cases of deafness have been shown to result from hereditary causes. The breeds for which the prevalence is known to be high are highlighted in bold, although similar high rates may occur in other breeds that do not yet routinely receive testing. Prevalence rates measured by the author are shown in Table 2 for the canine breeds most often presented for hearing testing services. The highest rates are seen in Dalmatians, of which 30% are deaf in one or both ears; rates in other strongly affected breeds range from 8% to 20%. Typically, there are two to three unilaterally deaf animals for every bilaterally deaf animal. In breeds with white versus non-white phenotypes (Bull Terrier, English Cocker Spaniel), there is a clear increased prevalence in the white phenotype. Prevalence rates for pure feline breeds have not been measured, but are highest for the breeds carrying the white gene (Table 3), especially in cats with blue eyes. Deafness in 256 mixed breed white cats was reported as 12% unilateral and 38% bilateral, for a total of 50% of cats being affected (reviewed in Delack3). The prevalence of deafness increases as the number of blue eyes increases from zero to two, but not all blue-eyed white cats are deaf. Deafness prevalence (unilateral and bilateral) in mixed breed white cats was 17%, 40%, and 85% for zero, one, or two blue eyes, respectively.(9)


Table 2. Dog Breed-Specific Deafness Prevalence (percent)

Breed
 Dogs
 Bilaterally Hearing
Unilaterally
Bilaterally

 Total

Tested

Deaf
Deaf
Deaf
Dalmatian
5009
70.2% (3510)
22.0% (1100)
8.0% (399)
30.0% (1499)
Bull Terrier
573
89.0% (510)
 9.9% (57)
1.0% (6)
11.0% (63)
 white
299
80.9% (242)
17.1% (51)
2.0% (6)
19.1% (57)
colored
272
97.8% (266)
2.2% (6)
0.0% (0)
2.2% (6)
English Setter
530
85.7% (454)
12.1% (64)
2.3% (12)
14.3% (76)
English Cocker Spaniel
828
92.8% (768)
6.2% (51)
1.1% (9)
7.2% (60)
 parti color
794
92.6% (735)
6.3% (50)
1.1% (9)
7.4% (59)
solid color
34
97.1% (33)
2.9% (1)
0.0% (0)
2.9% (1)
Australian Cattle Dog
238
87.4% (208)
10.5% (25)
2.1% (5)
12.6% (30)
Catahoula Leopard Dog
48
31.3% (15)
27.1% (13)
41.7% (20)
68.8% (33)
Jack Russell Terrier
47
80.9% (38)
8.5% (4)
10.6% (5)
19.1% (9)
      
GENETICS OF DEAFNESS
Pigment-associated deafness has been reported since the last century,(1,5,8-10,12) but the hereditary mechanisms are not yet fully understood. The merle gene, which is responsible for the pattern of dark and light hair in breeds such as the Collie and Shetland Sheepdog, is a simple autosomal dominant gene.(7) Dogs that are homozygous for the merle gene are usually deaf and frequently solid white, blind, and sterile. Heterozygotes have an increasing tendency to be deaf as the percent of white in the coat increases. Although the merle geneis a dominant gene, the deafness associated with it is not inherited as a simple dominant (or recessive) disorder.

The piebald and extreme piebald genes, which are responsible for white hair in nonmerle breeds of dogs, are simple autosomal recessive genes.(7) As a result, in breeds with major white areas on the body, the animals are homozygous. An example is the Dalmatian, all of which are breed are homozygous for the extreme piebald gene. The underlying coat color of black (dominant) or liver (recessive) is covered with white by the extreme piebald gene, and spots are produced through the white by the dominant ticking gene. The lightness or heaviness of the spotting is thus controlled by the ticking gene and not the extreme piebald gene, and it is not a factor in the prevalence of deafness.(19) Based on studies of the Dalmatian, deafness in breeds carrying the piebald genes is neither simple recessive nor dominant. Breeding of bilaterally hearing parents routinely produces deaf offspring; thus, the mechanism is not simple dominant. Breeding of two bilaterally deaf parents produces both deaf and hearing offspring; the latter would not occur if the defect were simple recessive and both parents were homozygous. There is no evidence for X-linked or mitochondrial hereditary mechanisms. As a consequence, inheritance of deafness associated with the piebald genes must be polygenic or must involve incomplete expression or penetrance, or some combination. Molecular genetic studies of deafness disorders in humans and mice suggest that this deafness may result from a defect in a gene responsible for regulation of the piebald genes such as one of the homeobox class of genes. Evidence for this comes from further findings in Dalmatians. A patch in Dalmatians is a large black or liver area present at birth when the puppy is otherwise solid white; patches are disallowed in the Dalmatian breed standard. The patch appears to result from weak expression of the extreme piebald gene, resulting in a failure to cover the underlying coat color; patched Dalmatians are statistically less likely to be deaf than unpatched animals.(19) When the extreme pieblad gene is strongly expressed, brown pigment is suppressed in the iris, resulting in blue eyes (and frequently an absence of pigment in the tapetum lucidum), and melanocytes are suppressed in the cochlear stria vascularis, resulting in deafness. Blue-eyed Dalmatians are statistically more likely to be deaf than brown-eyed animals.(19) The blue eye is permitted in the breed standard in the United States but not in Canada, Mexico, or Europe. The prevalence of deafness is lower in Europe (combined unilateral and bilateral deafness is 21% in the United Kingdom and 18% in Holland compared to 30% in the United States), and breeding away from blue eyes was shown to reduce deafness in Norway.(4) It is not known if differences exist for deafness associated with the two different piebald genes.

Table 3. Cat Breeds Carrying the White (W) Coat Pigment Gene
White
White Scottish Fold
European White
White Turkish Angora
Foreign White
White American Wirehair
White Cornish Rex
White American Shorthair
White Devon Rex
White British Shorthair
White Manx
White Exotic Shorthair
White Persian
White Oriental Shorthair


Deafness in the Doberman Pinscher, which is accompanied by transient vestibular dysfunction, is transmitted by a simple recessive mechanism.(23)

Pigment-associated congenital hereditary sensorineural deafness in the cat is linked to the white gene, which is dominant over color and is unrelated to albinism.(13) On occasion these cats will have a head spot and usually have one or two blue eyes. Although the white gene is dominant, not all carriers are deaf; thus, deafness is not simply inherited.

BEHAVIORAL INDICATORS OF DEAFNESS
Newborn puppies and kittens with undeveloped auditory and visual function use other sensory cues for their feeding, elimination, and locomotion behaviors. As auditory development proceeds, they can detect loud noises, despite the unopened ear canal. Breeders relying on this for home testing may find themselves to have been in error at a later date. Behavioral testing of hearing after opening of the canal relies on detection of a response to sound stimuli in the absence of other detectable sensory signals. These noises should be produced outside of the visual fields, avoiding visual cues, vibratory cues, touch, and air movements. Behavioral testing has limited value; animal responses rapidly adapt even when hearing is present, stressed animals with intact hearing may fail to respond, and unilateral deafness cannot be detected. In unilaterally deaf animals, the only behavioral sign of deafness is a difficulty in localizing the source of a sound, and many animals adapt to that also. Behavioral deafness detection with young animals in the home is difficult, as the deaf young cue off the behavior of their littermates. A puppy or kitten that does not awaken in response to a loud noise is almost certainly bilaterally deaf, but the unilaterally deaf cannot be detected with any reliability. As a consequence, behavioral hearing assessment of animals in the clinic or home is of limited reliability, and electrodiagnostic tests are used for objective assessment.

ELECTRODIAGNOSIS OF DEAFNESS
The most widely used electrodiagnostic test of hearing is the brain stem auditory evoked response (BAER), also known as the brain stem auditory evoked potential (BAEP) or the auditory brain stem response (ABR). This test was first used in veterinary research applications in the 1970s, and in clinical veterinary applications in the early 1980s. The BAER detects electrical activity in the cochlea and auditory pathways in the brain in much the same way that an electrocardiogram detects electrical activity in the heart.(17) The response waveform consists of a series of peaks labeled with Roman numerals: peak I is produced by the cochlea and auditory nerve, and later peaks are produced within the brain. The response from an ear that is deaf is an essentially flat line. In the sample recordings in Figure 2, the Dalmatian puppy in tracing A could hear in the tested ear, although the Dalmatian puppy in tracing B was deaf in the tested ear, with an essentially flat response. Because the response amplitude is quite small, it is necessary to average the responses to multiple stimuli (clicks) to unmask them from the other unrelated electrical activity that is also present on the scalp (e.g., electroencephalographic activity, muscle activity).

deafness2
Figure 2. Brain stem auditory evoked responses (BAER) recorded from puppies; cat BAER appear similar. A. A BAER from a normal dog in response to an air-conducted click stimulus. Peak I in the response is generated by the cochlea and VIIIth cranial nerve, while later peaks are generated in brain stem structures. B. A BAER from a dea0f Dalmatian. C. A BAER from a normal dog in response to a bone-conducted click stimulus.

The response is collected with a special computer through small subdermal needle electrodes: one is placed in front of each ear, one is placed at the top of the head, and a ground electrode is placed either between and behind the eyes or on the neck. It is rare for a dog to show any evidence of pain from the placement of the electrodes - if anything the dog objects to the gentle restraint and the presence of wires hanging in front of its face. A stimulus click (air-conducted) produced by the computer is directed into the ear with a foam insert earphone. Each ear is tested individually, and the test usually is complete in 10 to15 minutes. Sedation or anesthesia is unnecessary unless the dog becomes extremely agitated, which can usually be avoided with patient and gentle handling. Sedation or anesthesia does not materially affect the BAER.

The click stimulus used contains most of the audible frequencies of the dog and cat, with the exception of the very highest perceived frequencies. Accordingly, the BAER is a frequency nonspecific test that is more useful for detecting the presence or total absence of auditory function without quantifying hearing loss in decibels. Assessment of the normalcy of a response is based on identification of the presence of Peak I within a narrow expected time frame (which varies based on the equipment used) and the presence of the expected pattern of peaks. With progressive hearing loss, there is a reduction in the amplitude of the BAER peaks and an increase in peak latencies; thus, a subjective assessment of partial hearing loss can be made but not quantified, and differing degrees of loss in different frequency ranges cannot be determined. Diagnosis of partial hearing loss based on the BAER is done only with great caution, as a number of technical factors can affect peak amplitude and latency in subjects with normal hearing.(17) Fortunately, partial hearing loss is rare in puppies or kittens.

The BAER demonstrates maturational changes.(22) Because the greater portion of the BAER originates in the brain stem, there is less postnatal development than is seen in tests of other sensory modalities; however, postnatal development is greater in altricial species like the dog and cat than in precocial species like the horse and cow. Full maturation of the BAER occurs by 40 days in the dog and the cat. The BAER can be recorded in response to loud stimuli prior to the opening of the ear canal, but this is not of use as it predates the age at which deafness is manifested.

In some circumstances, it is useful to be able to differentiate between sensorineural and conductive deafness, as this can affect breeding decisions and whether a young animal is placed in a show home or a pet home. When a BAER indicates deafness in an animal in which conduction deafness might be suspected (i.e., long-eared breed, recent ear infection), the test is repeated with a mechanical transducer that transmits the stimulus click as a vibration through bone rather than through air conduction.20 Because the cochlea is imbedded in bone, the bone-conducted BAER bypasses the outer and middle ears, the sites of conduction blockade, and directly activates the cochlea. The response appearance is the same as an air-conducted BAER, but the peaks occur at a shorter latency due to the shorter path traversed by the stimulus (Figure 2).

A limited availability of BAER testing sites blocks some potential users from access, but the number of test locations is increasing beyond the original veterinary school sites. The equipment cost of approximately $20,000 and an absence of formal veterinary training programs outside of neurology residencies have impeded ready access. A listing of available national and international sites is maintained at the author's Web site,(16) which is also a resource of additional information on deafness.

CLIENT COUNSELING ISSUES
Advice to clients faced with a deaf puppy or kitten varries based on breed, animal age, home environment, unilateral versus bilateral deafness, and other factors. Bilaterally deaf animals present a variety of liabilities and emotional land mines, more so for dogs than for cats. Deaf animals are at risk of injury or death from undetected dangers such as motor vehicles. When startled, they may reflexly bite, which is a special concern around infants and toddlers. Anxious or aggressive personalities may develop in deaf dogs from constantly being subjected to startle, and familiar family members and friends may be attacked without warning or cause. Not all deaf dogs develop these problems, and no data exist on prevalence rates for such events, but there is no way to predict which animals may or may not have these experiences. Based on inherent temperament differences, there may also be variation between breeds in the likelihood of such problems. Bilaterally deaf dogs are very difficult to raise and train; as a result, they often end up in animal control shelters. From there, they may be reclaimed by breed rescue groups, after which the cycle may begin again. House cats present fewer problems, but outdoor cats may fall victim to motor vehicles. An emotional cost is invariably paid by the owners of those animals that cannot cope or adjust to their disability, both from the perspective of management and that of facing the decision as to whether to euthanize an animal with which an emotional attachment has formed. Unilateral deafness does not pose such problems.

Because of the many problems associated with bilaterally deaf dogs and the surplus of available puppies, the Dalmatian Club of America has an official position calling for the euthanasia of deaf puppies, with the emphasis on breeders rather than new owners. Similar sentiment is held by the official organizations of other breeds with high deafness prevalence rates, but these groups have not adopted such an official policy. This position has generated considerable controversy within the purebred dog community, the general dog-owning community, the veterinary community, and the human deaf community, but it is probably appropriate when divorced from emotional considerations.

Resources exist for those owners opting to keep a deaf dog. Books have been written on living with a deaf dog,(2) including directions for training deaf dogs to respond to American Sign Language signs, and web pages have been posted with information and support content. Deaf dogs and cats learn to respond to flashing porch lights and vibrating collars,(16) and can cue off the behavior of other animals in the household. In such circumstances, the owner should be instructed in protecting the animal from the inherent dangers associated with deafness: both dangers to the deaf animal and dangers to people around the deaf animal.

Genetic counseling for owners of deaf dogs and cats cannot be presented with total assurance because of the incomplete knowledge of mechanisms of deafness inheritance. It can be stated that deaf animals in breeds with a high known prevalence of either unilateral or bilateral deafness should not be bred; unilaterally deaf animals have the genetic defect but have one ear spared. Over the long run, such breedings have the probability of producing more deaf animals. In addition, it may not be advisable to breed to animals from litters which had a high percentage of deaf animals or from lines with a history of producing high percentages of deaf animals. The most conservative approach avoids any possible introduction of defective genes, but may be difficult in certain breeds. A deaf animal from one of these breeds must be assumed to have hereditary deafness instead of acquired deafness unless the clinical history convincingly indicates otherwise. Because of the association between deafness and blue eyes in the Dalmatian, it is also advisable to not breed blue-eyed dogs from those breeds in which the blue eye is not a standard part of the breed phenotype.

If a deaf animal is presented from a breed with no history of notable numbers of deaf animals, the guidelines for advice are murkier. The most conservative approach is not to breed any affected animal, especially if the breed is one carrying piebald or merle genes, unless the clinical history suggests a likely acquired cause such as otitis or drug ototoxicity. Even these latter cases are not without risk unless precedent documentation of normal hearing exists.

In an effort to promote research to reduce deafness and provide data for potential breeders, several national breed organizations in this country have set up hearing registries either managed by the breed organization (e.g., English Setter Association of America) or by a contracted second party (e.g., Dalmatian Club of America managed by the Institute for Genetic Disease Control in Animals, Bull Terrier Club of America managed by the Orthopedic Foundation of America). The first registry is closed, although the second is open and the third offers the option of being either closed or open to qualified members of the public. Current canine deafness research focuses on determining mechanisms of inheritance from extended pedigrees and on identifying the responsible defective genes using molecular biological techniques.

References
1. Anderson H, Henricson B, Lundquist P-G, et al: Genetic hearing impairment in the Dalmatian dog. Acta Oto-Laryngol Suppl 23:1, 1968
2. Becker, SC: Living With a Deaf Dog. Cincinnati, Susan Cope Becker, 1998
3. Delack JB: Hereditary deafness in the white cat. Compend Cont Ed Pract Vet 6:609, 1984
4. Greibrokk T: Hereditary deafness in the Dalmatian: Relationship to eye and coat color. J Amer Anim Hosp Assn 30:170, 1994
5. Hudson WR, Ruben RJ: Hereditary deafness in the Dalmatian dog. Arch Otolaryngol 75:213, 1962
6. Johnsson LG, Hawkins JE Jr, Muraski AA, et al: Vascular anatomy and pathology of the cochlea in Dalmatian dogs. In: de Lorenzo, AJD (ed): Vascular Disorders and Hearing Defects. Baltimore: University Park Press, 1973, p 249
7. Little CC: The Inheritance of Coat Color In Dogs. New York: Howell, 1957
8. Lurie MH: The membranous labyrinth in the congenitally deaf collie and Dalmatian dog. Laryngoscope 58:279, 1948
9. Mair IWS: Hereditary deafness in the white cat. Acta Otolaryngol Suppl 314:1, 1973
10. Mair IWS: Hereditary deafness in the Dalmatian dog. Arch Otorhinolaryngol 212:1, 1976
11. Pujol R, Hilding D: Anatomy and physiology of the onset of auditory function. Acta Otolaryngol 76:1, 1973
12. Rawitz B: Gehörorgan und Gehirn eines Weissen Hundes mit blauen Augen. Morphol Arbeiten 6:545, 1896
13. Searle AG: Comparative Genetics of Coat Color in Mammals. London: Logos Press, 1968
14. Strain GM: Congenital deafness in dogs and cats. Compend Cont Ed Pract Vet 13:245, 1991
15. Strain GM: Aetiology, prevalence, and diagnosis of deafness in dogs and cats. Brit Vet J 152:17, 1996
16. Strain GM: Deafness in dogs and cats. Located at: http://www.lsu.edu/deafness/deaf.htm
17. Strain GM: Electrophysiological assessment of auditory function. Proc. 15th ACVIM Forum 15:617.1997.
18. Strain GM, Jackson RM, Tedford BL: Postnatal development of the visual-evoked potential in dogs. Am J Vet Res 52:231, 1991
19. Strain GM, Kearney MT, Gignac IJ, et al: Brainstem auditory evoked potential assessment of congenital deafness in Dalmatians: associations with phenotypic markers. J Vet Internal Med 6:175, 1992
20. Strain GM, Green KD, Twedt AC, et al: Brain stem auditory evoked potentials from bone stimulation in dogs. Am J Vet Res 54:1817, 1993
21. Strain GM, Tedford L, Jackson RM: Postnatal development of the brainstem auditory-evoked potential in dogs. Am J Vet Res 52:410, 1994
22. Strain GM, Merchant SR, Neer TM, et al: Ototoxicity assessment of a gentamicin sulfate otic preparation in dogs. Am J Vet Res 56:532, 1995
23. Wilkes MK, Palmer AC: Congenital deafness and vestibular deficit in the doberman. J Small Anim Pract 33:218, 1992

George M. Strain, PhD Comparative Biomedical Sciences
School of Veterinary Medicine Louisiana State University
Baton Rouge, LA 70803 (225) 578-9758 (225) 578-9895 (fax)
strain@lsu.edu

*******************


back to top

deaf5

TRAINING YOUR DEAF DOG


 SOME TIPS & TRICKS FROM THE EVERYDAY PEOPLE WHO HAVE DISCOVERED THAT IT REALLY ISN’’T AS HARD AS YOU MIGHT THINK!!

deaf1

Many people have said that deaf dogs are impossible to train, that only the best trainers are up to the task, and that those few who do succeed are just lucky exceptions to the rules.

The members of DDEAF (Deaf Dog Education Action Fund), a 501(c)(3) nonprofit organization formed to “speak on behalf of and to assist in the betterment of life for deaf dogs everywhere,” and the thousands of people who have taken advantage of our email list would take exception to that. We are, for the most part, just regular people with regular dogs that really don’t listen to us.

deaf2 Getting started…
First of all, let’s talk about the things that you don’t need when you start training a deaf dog. You don’t need a vibrating collar or any other special tools. You don’t need to go looking for a special trainer. You don’t need a lot of extra time or patience and you don’t even need to worry about learning a new language. We use hand signs, facial expressions and other body cues to communicate with each other without ever thinking about it.

Unless your dog has recently and suddenly lost its hearing, or if it is a new rescue that has just found its way into your life, you should not have to worry about surprising or startling it. A healthy, well-loved, confident dog generally does not have any adverse reaction to life’s little unknowns. If startling is a concern for you, do it often and make it fun to be surprised!

deaf3

From Susan Cope Becker’s “Living With A Deaf Dog”

You do need a way to get and hold your deaf dog’s attention. Use a food treat or a favorite toy. Remember to keep your training sessions shorter for the younger dogs. Frequency, not duration, will be the key to your successful training times. Make sure that you and the dog are both having a great time and you can’t go wrong.

To get your dog’s attention you might have to be a little more creative. By stomping the floor or banging a wall to create a vibration, or by flashing lights on and off, you can often get the desired effect. When you’re outside, a big wave, throwing a ball or another toy in the air or toward the dog, or walking around are all good ways to attract attention. Movements big enough for the dog to see will be the key.

1 There are no right signs and no wrong signs. Basic obedience signals give you a place to start but regional sign languages allow you to keep expanding your vocabulary.

2 Try to keep to one-handed signs so you have a free hand for the leash or treats or anything else.

3 Make them simple motions that are easy for you to remember. You need to be consistent if you expect the dog to be.

4 Make sure that the signs are different enough from each other to avoid confusion. While a dog can know several different signs for a single behavior, each sign should only get one proper response.

5 Teach a new sign slowly and exaggerate the movement until the dog understands. Remember, too, that the greater the distance between you and the dog, the bigger the signing motion needs to be.

And there you have it. So let’s all get out there and start training!
deaf4

The mission of the Deaf Dog Education Action Fund is to provide education and funding for the purpose of improving and/or saving the lives of deaf dogs around the world.

To accomplish this, we are committed to do the following:
• To provide educational and training materials to combat the myths and misinformation that surround deaf dogs.
• To provide a central organization where the owners and supporters of deaf dogs can create a unified voice to increase people's understanding about deaf dogs.
• To gather and share facts and figures about canine deafness and deaf dog behaviors. By collecting data from those with firsthand experience, we hope to document the realities of living with deaf dogs.
• To lobby kennel clubs and other sanctioning bodies to accept deaf dogs into obedience, agility, and other skill competitions under the same conditions as other competitors.
• To provide a network between those seeking to place a deaf dog into a good home and those interested in bringing a deaf dog into their lives.
• To establish and maintain a travel fund to assist in the transportation of deaf dogs to their new homes and owners.
• To work toward ending the euthanization practices of the many breed clubs and breeders who treat deafness as a death sentence for the dogs.
• To promote spaying and neutering of all pets and encourage responsible breeding practices to reduce the pet overpopulation problem.


For More information on Training a deaf dog

EVERY YEAR THOUSANDS OF DOGS ARE KILLED SIMPLY BECAUSE THEY ARE DEAF!
DDEAF is working with deaf dog owners around the world to stop this injustice.
Contact us about becoming a member or to get other information and help save a life!
To join the Deaf Dogs Mailing List: http://groups.yahoo.com/group/deafdogs
Or visit the DDEAF Web Site at: www.deafdogs.org
Our e-mail address is: ddeaf@deafdogs.org
Regular mail can be sent to: Deaf Dog Education Action Fund
PO Box 2840, Oneco, FL 34264-2840 U.S.A.
reprinted with kind permission from Jack www.deafdogs.org


********************

back to top

Why should deaf dogs be victimised?   

 
Is it due to lack of understanding on our part, or perhaps we don’t have the imagination or patience to train them? 
barryeatonbook
Hear, Hear! - A Guide to Training the Deaf Dog
Hear Hear! goes through training a deaf dog step-by-step. It covers basic training that most pet dog owners require, including teaching the dog to sit, lay down, stand, walk nicely on a lead, stay, and to come back when ‘called’. It also covers important subjects like socialisation and suggests ways of overcoming some of the most common unwanted behaviour, like jumping up, barking and preventing your dog becoming destructive when left on its own. The moral issues of finding a home for a deaf dog are also discussed.
The book costs £7.75 including UK post and packing and is available by sending a cheque made payable to Barry Eaton - (and please remember to include your own name and address)


United Kingdom
United States of America
Other Countries
Barry Eaton,
Pine Cottage
Station Road
Chilbolton
Hampshire
SO20 6AL
United Kingdom

For customers in the USA, the book can be obtained from Dogwise. Please visit their web site on www.dogwise.com

Germany www.animal-learn.de



*************************

petpager

Pet Pager

petpagerbox
This was designed to help pet owners to silently call their dogs from a distance. It can be also used to dissuade or interrupt negative behaviour. It works in the same way as a personal pager. The pet owner sends a signal to their pet, which activates a receiver collar that vibrates when receiving a signal.  The pager is essential for owners of deaf or partial hearing dogs.

Purchase Here www.drivall.com


********************

Useful Websites

Hearing in Working Dogs
The Deaf Dog Education Action Fund
Raising a Deaf Dog
How to Determine if Your Dog is Deaf
Books
Deafness in Dogs and Cats
Deaf Dog Atlas
Deaf Dog Training
Resources for Deaf Dog Owners
Humphry
A Deaf Dalmation

Deaf Dog Info Site
Crickets Training
Deaf Dogs
Constructing a Vibrating Collar
Teaching Basic Commands
Training a Deaf Dog
Felix the Deaf Dalmation
Teaching Hand Signals




chloebutton  talabutton  

The above information is simply informational. It's intent is not to replace the advice of a veterinarian nor to assist you in making a diagnosis of your pet. Please consult with your own veterinarian for confirmation of any diagnosis. Your pets life may depend on it.