Introduction

• Fear is a normal, adaptive response to threats (real or perceived). Phobia is a pathological response that is maladaptive.
• Cause: the fear response may be learned or predisposed by genetics and the environment.
• Signs: dogs may show autonomic and behavioral signs and the fear responses may vary in intensity and frequency.
• Diagnosis: based on the behavioural history provided by the owner. A baseline level should be defined through an objective measurement of the response where possible. Before treatment is started consider the potential risks and benefits to animal and owner.
• Treatment: environmental management, behavior modification and in some cases medication.
• Prognosis: generally positively correlated with owners' compliance and less influenced by severity of the response, number of signs, early development of the fear, and generalization to similar noises. In animals with a high genetic propensity for fear behavior the long term prognosis is poor without adjunctive therapy.
  Print off the owner factsheet on Noise sensitivities Noise sensitivities to give to your client.

Pathogenesis

Etiology

• Fear is an adaptive response that develops as part of a risk assessment process. It contributes to decisions about whether the best strategy is engagement of avoidance. When avoidance or escape responses are thwarted, or the animal has little perceived control over the problem (entrapment), the response may intensify and persist.
• A number of events or situations (discussed in the pathophysiology section) may favor the development of problematic responses to noises.

Predisposing factors

• There is some association between dogs showing anxiety and attachment-related behavior problems or physical diseases, increasing blood pressure or adrenal activity with the development of noise sensitivities.
• Fearful temperament (dogs more sensitive to negative stimuli) may be more likely to develop noise sensitivities.
• Early non-domestic (ie rearing outside a home environment) maternal environments (eg kennels, garages) are associated with increased likelihood of avoidance behaviors during later life.

Specific

• Lack of experiences of noisy environment during puppyhood.
• In herding breeds and their crosses studies have shown some genetic predisposition in certain families. This may also be present in other breeds.

Pathophysiology

• Associative processes (Pavlovian conditioning) may be involved in the development of some noise sensitivities. Pavlovian (classical) conditioning is involved if dogs develop the fear response after traumatic experiences related to noise (fireworks, storms, gunfire). Despite owners' frequent reports, research has failed to confirm the development of fear through social learning (ie the observation of fearful responses in other dogs or humans).
• Non associative processes (lack of habituation, sensitization, stress-induced dishabituation) may increase risk of development of noise sensitivities. Sensitization is the gradual intensification of the fear response occurring with repeated presentations of the triggering stimulus: the process is more likely to happen for thunderstorm fear and dogs tend to show behavioral signs associated with autonomic arousal, such as panting, pacing, hypervigilance (scanning the environment all the time) and restlessness. Chronic and acute stress may impair the ability to adapt to the environment and decrease the threshold for fear responses, favoring the development of fears and phobias to stimuli to which the dog was previously habituated.
• Behavioral manifestations of fear (which do not correlate with the underlying level of arousal) may also develop: owners may involuntarily reinforce manifestations of fear associated with noises. The fear response becomes an attention seeking behavior that can be associated with the absence of autonomic signs.
• In one study animals with low or borderline thyroid levels had a higher propensity to show fear responses. Although treatment for hypothyroidism Hypothyroidism was associated with improvement of signs of noise fear, the causality correlation between low thyroid levels and noise fear is not clear.

Timecourse

• Unfortunately a lack of complete data and reporting means that there is poor evidence on timecourse for development of signs.
• Dogs may show fear responses of increasing severity with repetition of the triggering stimuli, the problem may gradually develop.
• In the case of non-associative processes, the onset may be sudden and at later ages.

Epidemiology

• Incidence of the problem is not well known. Occurrence of the problem has been observed to be up to 49% of the dog population (Blackwellet al, 2005). However, the problem is referred to specialists much less frequently by owners. Vets should discuss the importance of monitoring dogs' responses to noise. Owners should be advised that if their pet shows any extreme reaction, or fear from which it does not quickly recover or any early or concerning untoward response they should seek an immediate veterinary consultation.

Diagnosis

Treatment

Prevention

Outcomes