Acquired Numbness in Dogs (Anacusis)
- Synonyms: Deafness, Surditas, Kophosis
- Occurrence: rarer
- Location of disease: Head/Neck
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Anacusis, also known as complete deafness, is a condition in which a dog can no longer perceive sound. It is a complete loss of hearing in one or both ears.
The most important facts at a glance
Anacusis, or deafness in dogs, can be congenital or acquired. Congenital deafness is often genetically determined and occurs more frequently in certain breeds like Dalmatians and Bull Terriers, often associated with coat colors. Problems can arise in various areas of the auditory system, from the outer ear canal to the inner ear, where hair cells convert vibrations into electrical signals. Acquired deafness can be caused by infections, injuries, or age-related hearing loss. Symptoms include a lack of response to sounds and startle response / jumpiness.
Diagnosis begins with a medical history and physical examination by the veterinarian. The BAER test measures electrical activity in the brain in response to acoustic stimuli and helps determine the extent of hearing loss. Imaging techniques such as CT or MRI can reveal structural anomalies. For ear infections, an examination with an otoscope may be useful. Treatment options depend on the cause. Infections can be treated with medication, while genetic or age-related deafness is not curable. Here, the focus is on adapting training and communication through visual signals.
Prevention focuses on avoiding infections through regular veterinary check-ups and good ear hygiene. For susceptible breeds, responsible breeding practices are important to reduce genetic predisposition. Research aims to better understand genetic causes and develop regenerative medicine to restore hearing. The quality of life for deaf dogs can be improved through special training methods and aids.
Causes
The hearing of dogs works similarly to that of humans. Sound waves are transmitted through the external auditory canal to the eardrum, which vibrates. These vibrations are amplified by the ossicles in the middle ear and transmitted to the inner ear, where the hair cells in the cochlea convert the mechanical vibrations into electrical signals. These signals are then sent to the brain via the auditory nerve, where they are interpreted as sounds.
Deafness in dogs can arise due to problems in any of these areas. It can be congenital, meaning present at birth, or acquired. Congenital deafness is often genetically determined, while acquired deafness can be caused by various factors, including infections, injuries, or age-related hearing loss.
A common cause of congenital deafness in dogs is the inheritance of certain genetic traits, often associated with coat colors or patterns. Breeds such as Dalmatians, Bull Terriers, and Australian Shepherds are known to be more susceptible to genetically determined deafness. This form of deafness is usually associated with a defect in the development of the hair cells in the cochlea.
Acquired deafness can be caused by a variety of factors. Ear infections that are not adequately treated can damage the inner ear and lead to hearing loss. Traumas, such as a blow to the head, can also impair hearing. Chronic ear inflammations, which lead to a thickening of the eardrum or the formation of scar tissue, are also possible causes. In addition, the natural aging process can lead to a degeneration of the hair cells in the inner ear, which is common in older dogs.
Symptoms
A dog with deafness often shows Behavioral changes that indicate hearing loss. A common symptom is the inability to respond to noises or commands. The dog may also be difficult to wake from sleep because he does not perceive ambient noises.
Another sign may be that the dog no longer listens to his name or does not respond to sources of noise that used to interest him. Some dogs with hearing loss also tend to Barking louder because they can no longer perceive their own volume.
Behavioral changes such as increased Startle response / jumpiness or Aggressiveness can also occur, as the dog feels insecure due to the lack of acoustic information. In some cases, the dog may also react excessively to visual stimuli because he relies more on his other senses.
Sudden hearing loss can also be the result of a trauma (petrous bone fracture). Bleeding from the ear and very strong pain reactions indicate this. Tumors in the ear area can also lead to deafness. Indications for this can be a persistent, therapy-resistant otitis, visible polyps or masses in the ear canal, as well as paralysis of the facial nerve (facial paresis).
Acute hearing loss, combined with pain, head tilted to one side, or neurological signs, should be clarified immediately.
Therapy
The treatment of deafness in dogs depends on the cause of the hearing loss. If there is a treatable underlying condition such as an ear infection, the veterinarian will prescribe appropriate medications to combat the infection and reduce the inflammatory conditions.
For genetically determined or age-related deafness, there is currently no cure that can restore hearing. In such cases, the focus of treatment is on helping the dog live with the hearing loss. This may include adjusting training and using hand signals or other visual cues to communicate with the dog.
Some dogs benefit from the use of vibration collars, which produce gentle vibrations to get the dog’s attention without startling him. It is important to provide the dog with a safe environment and give him time to adjust to his new situation.
Prognosis and follow-up care
The prognosis for dogs with deafness varies depending on the cause and extent of the hearing loss. For treatable causes like infections, the prognosis can be good if the condition is recognized and treated early. Hearing loss can be partially or fully reversed if the underlying cause is addressed.
In the case of genetically determined or age-related deafness, the hearing loss is usually permanent. Despite the loss of hearing, many dogs can live happy and fulfilling lives if they are properly supported. Adapting to hearing loss requires patience and consistent training for both the dog and the owner.
Dogs that are deaf from birth often adapt better because they have never learned to rely on hearing. They develop stronger visual and olfactory skills to perceive their environment.
Prevention
The prevention of deafness in dogs primarily focuses on avoiding acquired causes. Regular veterinary check-ups and good ear hygiene are crucial to detect and treat ear infections early, before they can lead to permanent damage.
For breeds susceptible to genetically determined deafness, it is important to promote responsible breeding practices. Breeders should use genetic tests and avoid breeding dogs that show known genetic predispositions for deafness. This can help reduce the risk of passing these genes on to future generations.
Dog owners should also regularly check their pets’ ears for signs of infections or inflammatory conditions and have them treated by a veterinarian if necessary. A balanced diet and a healthy lifestyle can also help promote the dog’s overall health and prevent age-related health problems.
Outlook on current research
Research into deafness in dogs has made significant progress in recent decades. Scientists are working to better understand the genetic causes of deafness, as many cases of congenital deafness – meaning deafness present at birth – are due to genetic factors. Certain dog breeds show a higher prevalence of deafness, indicating genetic predispositions. For example, Dalmatians, Australian Shepherds, and some Terrier breeds are more frequently affected. Researchers are identifying specific genes associated with deafness to help breeders make informed decisions and thus reduce the prevalence of this condition.
Another area of research focuses on the development and improvement of diagnostic techniques. Traditionally, deafness in dogs was diagnosed through behavioral observations and simple hearing tests. However, the use of Brainstem Auditory Evoked Response (BAER) tests is currently being promoted, which allow for a more accurate and objective determination of hearing ability. These tests measure electrical activity in the brain in response to acoustic stimuli and are particularly valuable for early diagnosis in puppies.
In addition, regenerative medicine is being explored as a promising area for future treatments. Some studies are investigating the possibility of regenerating damaged hair cells in the inner ear, as the loss of these cells often leads to deafness. Researchers are experimenting with stem cell therapy and genetic engineering approaches to restore or at least improve the function of the inner ear. These innovative approaches could play a revolutionary role in the treatment of deafness in the future.
Prevention measures are also an essential part of current research. Breeders and veterinarians are continuously informed about the latest findings to promote the prevention of deafness through targeted breeding strategies. In addition, environmental factors that can contribute to the development of deafness are being investigated, such as certain medications or infections that occur during pregnancy or in a dog’s early life.
Another goal of the research is to improve the quality of life of deaf dogs. This involves investigating training methods and aids that help deaf dogs interact more effectively with their environment. These include visual signals as a substitute for acoustic commands and the use of vibrating devices that can transmit certain signals to the dog. These measures help ensure that deaf dogs can lead a fulfilling and safe life.
Frequently Asked Questions (FAQs)
1. How can I tell if my dog is deaf?
2. Can all dog breeds be affected by numbness?
3. Is numbness in dogs curable?
4. Can a deaf dog live a normal life?
5. Can numbness in dogs be prevented?
6. How can I train a deaf dog?
7. Are there any special aids for deaf dogs?
8. Is numbness in dogs hereditary?
9. What role do environmental factors play in dogs' numbness?
10. How can I help my deaf dog feel safe?
Literature
- Strain, G. M. (2012). Canine deafness. Veterinary Clinics of North America: Small Animal Practice, 42(6), 1209–1224. https://doi.org/10.1016/j.cvsm.2012.08.010
- Oishi, N., Talaska, A. E., & Schacht, J. (2012). Ototoxicity in dogs and cats. Veterinary Clinics of North America: Small Animal Practice, 42(6), 1259–1271. https://doi.org/10.1016/j.cvsm.2012.08.005
- Fefer, G., Khan, M. Z., Panek, W. K., Case, B., Gruen, M. E., & Olby, N. J. (2022). Relationship between hearing, cognitive function, and quality of life in aging companion dogs. Journal of Veterinary Internal Medicine, 36(5), 1708–1718. https://doi.org/10.1111/jvim.16510
- Yang, C.-C., Yap, P.-T., Wu, Y., Zidan, N., Fefer, G., Nelson, N. C., Gruen, M. E., & Olby, N. J. (2024). Voxelwise analysis of the central hearing pathway in senior dogs reveals changes associated with fractional lifespan. Scientific Reports, 14, Article 18121. https://doi.org/10.1038/s41598-024-68828-3
- Stanger, A., Buhmann, G., Dörfelt, S., Zablotski, Y., & Fischer, A. (2024). Rapid hearing threshold assessment with modified auditory brainstem response protocols in dogs. Frontiers in Veterinary Science, 11, Article 1358410. https://doi.org/10.3389/fvets.2024.1358410
- Mason, C. L., Paterson, S., & Cripps, P. J. (2013). Use of a hearing loss grading system and an owner-based hearing questionnaire to assess hearing loss in pet dogs with chronic otitis externa or otitis media. Veterinary Dermatology, 24(5), 512–e121. https://doi.org/10.1111/vde.12057
- Cole, L. K., Rajala-Schultz, P. J., & Lorch, G. (2018). Conductive hearing loss in four dogs associated with the use of ointment-based otic medications. Veterinary Dermatology, 29(4), 341–e120. https://doi.org/10.1111/vde.12542
- Fisk, A., Londoño, L., Carrera-Justiz, S., & Buckley, G. (2019). Cochleotoxicity and acute kidney injury secondary to parenteral gentamicin administration in a dog. The Canadian Veterinary Journal, 60(9), 976–980.
- ter Haar, G., Mulder, J. J., van Venker-van Haagen, A. J., van Sluijs, F. J., Snik, A. F. M., & Smoorenburg, G. F. (2010). Treatment of age-related hearing loss in dogs with the Vibrant Soundbridge middle ear implant: Short-term results in 3 dogs. Journal of Veterinary Internal Medicine, 24(3), 557–564. https://doi.org/10.1111/j.1939-1676.2010.0486.x
- Bajwa, J. (2019). Canine otitis externa—Treatment and complications. The Canadian Veterinary Journal, 60(1), 97–99.