Anacusis (Congenital Hearing Loss) in Dogs
- Occurrence: rarer
- Location of illness: Head/Neck
CongenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. hearing loss refers to the condition in which dogs are unable to hear from birth. This condition can affect one or both ears and is often associated with genetic factors, especially in dogs with white fur or merle coloring. While unilateral hearing loss can be well compensated by the animal, bilateral anacusis leads to a massive restriction of environmental perception, communication and responsiveness.
In veterinary medicine, it is not only a clinically relevant topic, but also a characteristic of considerable importance from an animal welfare ethics perspective, especially in connection with certain breeding lines.
The most important facts at a glance
Anacusis, the complete Hearing loss, can be congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. or acquired in dogs and represents a significant sensorySensory refers to the senses or perception. Sensory systems in dogs and cats include sight, hearing, smell, taste, and touch, all of which are central to interacting with their environment. impairment, especially when it occurs bilaterally. The most common cause is hereditary, sensorineural inner ear damage in genetically predisposed breeds. The BAER test is essential for diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. The therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. depends on the cause, but is not possible in most congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. or toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. cases. Good quality of life can still be maintained through training, visual communication and a safe environment.
Causes
The causes of hearing loss in dogs can be divided into three main categories:
- CongenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. (inherited) causes:
These are usually genetically determined, irreversible sensorineural hearing loss. Dog breeds with pigment-altering genes such as Dalmatians, Bull Terriers, Australian Cattle Dogs, English Setters and Border Collies are particularly affected. The mechanism is based on a loss of function of the hair cells in the cochlea as a result of disturbed melanocyte development. This form often occurs bilaterally and manifests itself in the first weeks of life. - Acquired causes:
- Infections: ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. otitis media/interna, bacterial or mycotic labyrinthitis
- ToxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes.: OtotoxicOtotoxic refers to substances that are harmful to the ear and can lead to hearing damage or balance disorders. Certain medications and chemicals can have ototoxic effects. drugs such as aminoglycosides (e.g. gentamicin), diureticsDiuretics are medications that increase urine production in the kidneys to rid the body of excess salt and water. They are often used to treat high blood pressure, heart failure, and certain types of edema., cytostaticsCytostatics are drugs that inhibit cell growth or division and are used in the treatment of cancer to slow down or stop the proliferation of cancer cells.
- Traumatic: Traumatic brain injury, barotrauma
- Age-related degeneration: Presbycusis in geriatric animals
- Neoplastic: Tumors in the area of the inner ear or the vestibulocochlear nerve
- Autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus. such as vasculitic labyrinthopathies
- Functional or central causes:
Here, the damage is not in the ear itself, but in the area of the central auditory pathway, e.g. due to encephalitisEncephalitis is an inflammation of the brain, often caused by viral infections, which can lead to symptoms such as Fever, headaches, confusion, and in severe cases, seizures or impaired consciousness., neoplasiaNeoplasia refers to the uncontrolled, abnormal growth of cells or tissues, leading to the formation of a neoplasm or tumor. Neoplasias can be benign or malignant and require accurate diagnostic evaluation and treatment. or hypoxiaHypoxia refers to a condition in which the body or a part of the body is not supplied with enough oxygen. This can lead to various symptoms, including shortness of breath, confusion, and in severe cases, organ failure..
Symptoms
The clinical symptoms of hearing loss are subtle, especially in puppies, and can easily be overlooked. Common signs are:
- Lack of reaction to acoustic stimuli
- Difficult to train, does not respond to name calling
- Overreactions to touch or sudden movements
- Unilateral hearing loss: frequent Head tilted to one side, orientation to one side
- In the case of acquired hearing loss, possibly additionally: Balance disorders, Head tilted to one side, ataxia (with involvement of the vestibular organ)
A sudden Hearing loss in an adultThe term “adult” refers to an individual who has reached full physical development and is considered an adult. In veterinary medicine, this term is used to describe animals that have completed growth and are of reproductive age. dog often manifests itself through insecurity, Vocalizations or increased attention to visual stimuli.
Diagnosis
Diagnostics are carried out in several steps:
- Anamnesis and clinical examination, including otoscopic control to assess the external auditory canal
- Audiometry using BAER test (Brainstem Auditory Evoked Response): Gold standard for objective recording of auditory function. Brainstem audiograms are recorded to determine stimulus conduction from the inner ear to the brain. Particularly important for puppy testing before breeding use.
- Imaging (CT, MRI): Representation of the middle ear, inner ear, brain structures, helpful in suspected tumors, otitis media/interna or central causes
- Laboratory diagnostics in suspected infections or toxins (e.g. gentamicin levels)
- Genetic tests: In development for certain breeds, but so far only available for a few lines
Therapy
CongenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. and irreversible forms: These are not treatable, but adapting the environment and training with non-verbal signals are helpful.
A hearing prosthesis like in humans does not exist in veterinary medicine. Studies on cochlear implants in dogs are in an experimental stage. Training and communication through visual signs or vibration training can help guide and communicate with deaf dogs.
InfectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. otitis: Systemic and topicalTopical refers to the direct application of medications or treatments to the skin or mucous membranes for a local effect, without being absorbed into the body. antibiotics or antifungals, possibly surgical treatment (e.g. bulla osteotomyAn osteotomy is a surgical procedure in which a bone is cut or removed to correct alignment or improve a deformed bone structure.)
OtotoxicOtotoxic refers to substances that are harmful to the ear and can lead to hearing damage or balance disorders. Certain medications and chemicals can have ototoxic effects. drug exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats.: Immediate discontinuation of the triggering agent, symptomatic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions., prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. usually unfavorable in the case of inner ear involvement
Central causes: TherapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. of the underlying disease (e.g. encephalitisEncephalitis is an inflammation of the brain, often caused by viral infections, which can lead to symptoms such as Fever, headaches, confusion, and in severe cases, seizures or impaired consciousness., neoplasiaNeoplasia refers to the uncontrolled, abnormal growth of cells or tissues, leading to the formation of a neoplasm or tumor. Neoplasias can be benign or malignant and require accurate diagnostic evaluation and treatment.), symptomatic support
Prognosis and follow-up care
Dogs with congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. hearing loss can live a completely normal and fulfilling life, provided they receive appropriate training and adaptations to their environment. It is important to avoid stressful situations, sudden approaches without visual contact and potential dangers (e.g. road traffic).
Overall, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends heavily on the cause. With reversible, infectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. or inflammatory causes, a complete restoration of auditory function is possible. CongenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. or toxic inner ear damage is irreversible.
Follow-up examinations are particularly relevant in acquired forms in order to detect the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. or bilateral spread at an early stage.
Prevention
Congenital hearing loss cannot be cured, so prevention lies in responsible breeding. Carriers of affected genes, often with certain coat colors such as merle or extreme white, should be excluded from breeding. Genetic tests and BAER hearing tests in puppies enable early detection. Breeding associations recommend targeted pairings to reduce the risk. Education is important for owners: no mating of deaf animals, even if they otherwise appear healthy. Consistent breeding selectionSelection refers to the process of natural or artificial selection of specific individuals for reproduction, based on desired genetic traits. In breeding, this is applied to promote specific characteristics in dogs and cats. can significantly reduce the frequency of this hereditary disease in the long term.
Outlook on current research
Research focuses on the genetic characterization of deaf dog breeds, the development of predictive genetic tests and the exploration of regenerative inner ear therapies. Cochlear implants are also being tested experimentally, especially in working and assistance dogs. In neurobiology, the plasticity of the brain in congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. anacusis is being investigated in order to optimize therapeutic rehabilitation strategies. Further approaches aim at protective measures against ototoxicity, especially in medically necessary treatments with high-risk drugs.
Frequently asked questions (FAQs)
- Can my deaf dog lead a normal life?
Yes, with adapted education and a safe environment, a normal life is quite possible. - Is deafness hereditary?
Yes, especially in breeds with pigment defects such as Dalmatians – therefore important: BAER test before breeding approval. - How do I recognize deafness in a puppy?
Lack of reaction to noises, no waking up to noise, overreactions to touches. - Is there a therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. for congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. deafness?
No, but a good quality of life can be achieved through behavioral training and environmental adaptation.