Seizure-precipitating factors in dogs with idiopathic epilepsy

Idiopathic Epilepsy Risk Allele Trends in Belgian Tervuren: A Longitudinal Genetic Analysis

Idiopathic epilepsy (IE) has been known to be inherited in the Belgian Tervuren for many decades. Risk genotypes for IE in this breed have recently been identified on Canis familiaris chromosomes (CFA) 14 and 37. In the current study, the allele frequencies of these loci were analyzed to determine whether dog breeders had employed a purposeful selection against IE, leading to a reduction in risk-associated allele frequency within the breed over time. The allele frequencies of two generational groupings of Belgian Tervuren with and without IE were compared. Allele frequencies for risk-associated alleles on CFA14 were unchanged between 1985 and 2015, whereas those on CFA37 increased during that time in the control population (p < 0.05). In contrast, dogs with IE showed a decrease (p < 0.05) in the IE risk-associated allele frequency at the CFA37 locus. Seizure prevalence in the Belgian Tervuren appears to be increasing. These results suggest that, despite awareness that IE is inherited, selection against IE has not been successful.

Tools and techniques for classifying behaviours in canine epilepsy

Idiopathic epilepsy is the most common neurological disease in dogs. Similar to humans, dogs with epilepsy often experience behavioural comorbidities such as increased fear, anxiety, and aggression, as reported by their caregivers. Investigations of behaviour in canine epilepsy have yet to untangle interictal and pre and postictal behaviours, prodromal changes, and seizure-precipitating factors. Under-recognition of absence and focal seizures further complicates these assessments. These complex behavioural presentations in combination with caring for an epileptic animal have a significant negative impact on the dog's and caregiver's quality of life. Despite the growing recognition of behavioural comorbidities and their impact on quality of life in dogs with epilepsy, few objective research methods for classifying and quantifying canine behaviour exist. This narrative review examines the strengths, limitations, and granularity of three tools used in the investigation of canine behaviour and epilepsy; questionnaires, electroencephalography, and actigraphy. It suggests that a prospective combination of these three tools has the potential to offer improvements to the objective classification and quantification of canine behaviour in epilepsy.

Remarkable anecdotes illustrating the nature and effect of seizure-precipitating factors in Border Collies with idiopathic epilepsy

Epilepsy is one of the most common chronic neurological syndromes in dogs and has serious implications for the quality of life of both the dogs and owners. Seizure-precipitating factors (SPFs) (also termed "triggers" or "provocative factors") have been studied and reported in both humans and dogs with idiopathic epilepsy. In dogs stress, hormones, sleep deprivation, and the weather have been reported as SPFs. The Border Collie (BC) is a breed of dog that is predisposed to idiopathic epilepsy, and the outcome is often poor. BC is described as a very sensitive dog with a strong focus on their owners, and this may have an influence on their and their owners' stress level. In this article, we described six unrelated BCs with idiopathic epilepsy in which several remarkable SPFs were identified, and avoiding them improved the outcome of these dogs. The possible SPFs were different for each dog. The SPFs were, among others, the other dog in the family, the lack of intellectual challenge, the presence of an autistic child, a busy street, the relation with the owner, and throwing a ball at the beach. These cases illustrate that recognizing the SPF(s) and taking measures with regard to management can lead to a reduction in epileptic seizure frequency or even achieving seizure freedom.

Translational veterinary epilepsy: A win-win situation for human and veterinary neurology

Epilepsy is a challenging multifactorial disorder with a complex genetic background. Our current understanding of the pathophysiology and treatment of epilepsy has substantially increased due to animal model studies, including canine studies, but additional basic and clinical research is required. Drug-resistant epilepsy is an important problem in both dogs and humans, since seizure freedom is not achieved with the available antiseizure medications. The evaluation and exploration of pharmacological and particularly non-pharmacological therapeutic options need to remain a priority in epilepsy research. Combined efforts and sharing knowledge and expertise between human medical and veterinary neurologists are important for improving the treatment outcomes or even curing epilepsy in dogs. Such interactions could offer an exciting approach to translate the knowledge gained from people and rodents to dogs and vice versa. In this article, a panel of experts discusses the similarities and knowledge gaps in human and animal epileptology, with the aim of establishing a common framework and the basis for future translational epilepsy research.

Urinary Neurotransmitter Patterns Are Altered in Canine Epilepsy

Epilepsy is the most common chronic neurological disease in humans and dogs. Epilepsy is thought to be caused by an imbalance of excitatory and inhibitory neurotransmission. Intact neurotransmitters are transported from the central nervous system to the periphery, from where they are subsequently excreted through the urine. In human medicine, non-invasive urinary neurotransmitter analysis is used to manage psychological diseases, but not as yet for epilepsy. The current study aimed to investigate if urinary neurotransmitter profiles differ between dogs with epilepsy and healthy controls. A total of 223 urine samples were analysed from 63 dogs diagnosed with idiopathic epilepsy and 127 control dogs without epilepsy. The quantification of nine urinary neurotransmitters was performed utilising mass spectrometry technology. A significant difference between urinary neurotransmitter levels (glycine, serotonin, norepinephrine/epinephrine ratio, ɤ-aminobutyric acid/glutamate ratio) of dogs diagnosed with idiopathic epilepsy and the control group was found, when sex and neutering status were accounted for. Furthermore, an influence of antiseizure drug treatment upon the urinary neurotransmitter profile of serotonin and ɤ-aminobutyric acid concentration was revealed. This study demonstrated that the imbalances in the neurotransmitter system that causes epileptic seizures also leads to altered neurotransmitter elimination in the urine of affected dogs. Urinary neurotransmitters have the potential to serve as valuable biomarkers for diagnostics and treatment monitoring in canine epilepsy. However, more research on this topic needs to be undertaken to understand better the association between neurotransmitter deviations in the brain and urine neurotransmitter concentrations in dogs with idiopathic epilepsy.

Owner reported management of interictal anxiety behaviours in canine epilepsy

BACKGROUND

Idiopathic epilepsy (IE) is the most common chronic neurological condition in dogs, and can be associated with interictal (between seizure) anxiety (IIA). It is unclear how owners manage their pet's IIA, including how much veterinary support they receive for it.

METHODS

An international online questionnaire collected data on IIA prevalence, management of IIA and perceived levels of veterinary support for IIA from owners of dogs diagnosed with IE.

RESULTS

Valid responses were available from n = 220 owners. IIA was reported by 83.6% of owners. Common management strategies were behavioural or training techniques, reported by 90.4% of owners, whilst 34.4% reported use of behavioural products. Only 28.5% of owners felt fully supported by their vet in managing IIA. Owners who felt unsupported were less likely to have received advice on behavioural management or training from their vet (p = 0.003).

CONCLUSION

Access to veterinary support for the management of IIA is needed for owners of dogs with IE.

Research priorities for idiopathic epilepsy in dogs: Viewpoints of owners, general practice veterinarians, and neurology specialists

BACKGROUND

Epilepsy is the most common chronic neurological disease in dogs that adversely affects the quality of life (QoL) of affected dogs and their owners. Research on epilepsy in dogs is expanding internationally, but where best to focus limited research time, funds, and expertise to achieve better outcomes for affected dogs and their owners has not been studied.

OBJECTIVE

To explore idiopathic epilepsy (IE) research priorities of owners of dogs with IE, general practice veterinarians, and veterinary neurologists.

METHODS

An international online survey was conducted in 2016 and repeated in 2020. Participants rated the absolute importance and relative rank of 18 areas of IE research, which were compared between groups and time points.

RESULTS

Valid responses were received from 414 respondents in 2016 and 414 respondents in 2020. The development of new anti-seizure drugs (ASD) and improving the existing ASD management were considered the most important research priorities. Areas of research with increasing priority between 2016 and 2020 included non-ASD management, with the greatest potential seen in behavioral and dietary-based interventions. Disagreements in priorities were identified between groups; owners prioritized issues that impacted their and their dog's QoL, for example, adverse effects and comorbidities, whereas general practitioner vets and neurologists prioritized clinical issues and longer-term strategies to manage or prevent IE, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Ensuring that voices of owners are heard in the planning of future research should be a broader goal of veterinary medicine, to target research efforts toward areas most likely to improve the QoL of the dog-owner dyad.

Imepitoin for treatment of idiopathic head tremor syndrome in dogs: A randomized, blinded, placebo-controlled study

Background

Idiopathic head tremor syndrome is a paroxysmal movement disorder of unknown etiology. Spontaneous remission may occur, but owners may request treatment in severely affected dogs with continued episodes. Controlled studies of the disease are not available.

Hypothesis/Objectives

A drug with gamma amino butyric acid‐ergic and anxiolytic effects will decrease head tremor episodes.

Animals

Twenty‐four dogs with severe nonremitting head tremor and presumptive clinical diagnosis of idiopathic head tremor syndrome.

Methods

Prospective, blinded, placebo‐controlled clinical trial to compare imepitoin with placebo in dogs with frequent episodes of idiopathic head tremor. Evaluation of efficacy used the quotient T2/T1 that represented prolongation of the head tremor‐free period compared to a 3‐month baseline. A dog was considered a responder if tremors subsided or if the head tremor‐free period was 3× longer than the longest period during baseline (T2/T1 ≥ 3). Sample size calculations considered a large effect of imepitoin on T2/T1 (Cohen's d = 0.8).

Results

There were no responders in the placebo group (0/12). In the imepitoin group, the responder rate was 17% (2/12; P = .18) with T2/T1 3.8 and 4.0. Mean T2/T1 was 1.0 ± 1.4 in the imepitoin and 0.4 ± 0.4 in the placebo group (P = .37).

Conclusion and Clinical Importance

Imepitoin did not result in a significant overall benefit. Future studies should focus on treatment of subgroups with a common pathophysiology and similar comorbidities.

Impact of canine epilepsy on judgement and attention biases

Idiopathic epilepsy (IE) is the most common chronic neurological condition in dogs, characterised by recurrent seizure activity and associated with negative behavioural and cognitive changes. We hypothesised that IE would negatively impact putative affective state, with dogs with IE exhibiting a more pessimistic judgement bias and more negative attention bias than controls. Dogs were tested in a previously-validated spatial judgement bias task, and a novel auditory attention bias task testing attention to sounds with different valence or salience (neutral, novel pre-habituated, threatening). Sixty-eight dogs (IE = 33, Control = 35) were tested, of which n = 37 acquired the spatial discrimination and responses to judgement bias probes were tested (IE = 19, Control = 18), and n = 36 were tested for responses to sounds (IE = 20, Control = 16). Study groups did not significantly differ by age, sex, breed or neuter-status (p > 0.05). Main effects of study group were not significant in judgement bias (F_1,102 = 0.20, p = 0.658) or attention bias tasks (F_3,102 = 1.64, p = 0.184). In contrast with our hypotheses, there was no evidence that IE altered cognitive biases in this study population; however, dogs with IE were significantly more likely to be unable to learn the spatial discrimination task (p = 0.019), which may reflect IE-related cognitive deficits. Developing methods to test affective state without excluding cognitively impaired individuals is a future challenge for animal welfare science.

Investigating the potential for seizure prediction in dogs with idiopathic epilepsy: owner-reported prodromal changes and seizure triggers

BACKGROUND

Canine idiopathic epilepsy (IE) is characterised by recurrent seizure activity, which can appear unpredictable and uncontrollable. The purpose of this study was to investigate the potential for seizure prediction in dogs by exploring owner-perceived seizure prediction abilities and identifying owner-reported prodromal changes (long-term changes in disposition that indicate forthcoming seizures) and seizure triggers (stimuli that precipitate seizures) in dogs with IE.

METHODS

This is an online, international, cross-sectional survey of 229 owners of dogs diagnosed with IE, meeting the International Veterinary Epilepsy Task Force tier I diagnostic criteria.

RESULTS

Over half (59.6 per cent) of owners believed they were able to predict an upcoming seizure in their dog, of whom nearly half (45.5 per cent) were able to do so at least 30 minutes before the seizure commenced. The most common 'seizure predictors' were preseizure behavioural changes including increased clinginess (25.4 per cent), restlessness (23.1 per cent) and fearful behaviour (19.4 per cent). Nearly two-thirds of owners reported prodromal changes (64.9 per cent), most commonly restlessness (29.2 per cent), and nearly half (43.1 per cent) reported seizure triggers, most commonly stress (39.1 per cent).

CONCLUSIONS

The relatively high prevalence of owner-reported prodromal changes and seizure triggers shows promise for utilising these methods to aid seizure prediction in dogs, which could open a window of time for pre-emptive, individualised drug interventions to abort impending seizure activity.

Epileptic seizures triggered by eating in dogs

Background

Seizures triggered by eating (STE) behavior are very rare in humans and have not been documented previously in dogs.

Objectives

To document the occurrence of STE in dogs and describe their clinical features.

Animals

Ten client‐owned dogs with STE diagnosed at 5 European referral centers.

Methods

A call for suspected cases of STE was made online. This call was followed by a retrospective review of medical records, combined with a questionnaire to be completed by both the owner and the board‐certified neurologist who made the diagnosis. Cases were included if >50% of the seizures that occurred were related to eating and if a minimum diagnostic evaluation for seizures had been performed.

Results

Four cases only had STE and 6 cases had both STE and spontaneous seizures. Four of the dogs were retrievers. The most common seizure type was focal epileptic seizures evolving to become generalized. Nine dogs were diagnosed with idiopathic epilepsy. One dog had a presumptive diagnosis of glioma involving the margins of the parietal, temporal, and frontal cortex (the perisylvian region), an area known to have a key role in eating‐associated epilepsy in people. Treatment strategies included a combination of pharmacological management and eating habit changes.

Conclusions and Clinical Importance

We have identified a form of reflex epilepsy in dogs, with STE behavior. Further studies are warranted to improve the characterization and management of STE.

Behavioral Interventions as an Adjunctive Treatment for Canine Epilepsy: A Missing Part of the Epilepsy Management Toolkit?

Epilepsy is a common, complex and often challenging neurological disorder to treat in the dog, with 20-30% of dogs resistant to conventional medical therapies, and associated with cognitive and behavioral comorbidities and early death. Behavioral interventions are an emerging area of focus in the adjunctive treatment of drug-resistant human epilepsy patients, with studies indicating positive effects of a variety of interventions including relaxation-based techniques and behavioral therapy interventions. Behavioral interventions have the potential not only to improve seizure control, but also improve behavioral comorbidities and general quality of life in this hard to treat patient group. Despite striking similarities between human and canine epilepsy patients, including the recognition of co-morbid anxiety in epilepsy patients, behavioral interventions have yet to be studied in dogs. This is compounded by several licensed psychopharmaceutical agents for dogs being contra-indicated in epilepsy patients. We present evidence from human studies of the efficacy of behavioral interventions to improve seizure control, psychiatric comorbidities and quality of life, and propose that adapting such interventions for canine patients may be a valuable addition to the epilepsy management toolkit. There is a need for multi-center, double-blinded, placebo-controlled trials to confirm the effects of behavioral interventions on seizure frequency in veterinary medicine. In the absence of such evidence to date, the use of established behavioral medicine techniques to reduce stress and improve the mental health of these often sensitive and challenging patients is advocated, with a greater role for behaviorists in the management of epilepsy patients alongside neurologists and general practitioners.

Seizure-precipitating factors in dogs with idiopathic epilepsy

Background

Stress, sleep deprivation, and infectious diseases are important seizure‐precipitating factors in human epilepsy patients. However, these factors have not been thoroughly studied in epileptic dogs.

Objective

Seizure‐precipitating factors are common in dogs with idiopathic epilepsy and the occurrence of these factors associate with the dogs' signalment, personality, and epilepsy‐related factors.

Animals

Fifty dogs with diagnosed idiopathic epilepsy from the hospital populations of University Veterinary Teaching Hospital of University of Helsinki and Referral Animal Hospital Aisti.

Methods

In a retrospective cross‐sectional observational study, owners were interviewed about their dogs' possible seizure‐precipitating factors according to a predefined questionnaire. The dogs were identified and selected by searching the medical records of the participating animal hospitals.

Results

The prevalence of seizure‐precipitating factors in the study population was 74% (37/50). The most frequently reported factors included stress‐related situations, sleep deprivation, weather, and hormonal factors. In dogs with focal onset seizures, the number of precipitating factors was 1.9 (95% CI 1.1‐3.4) times higher compared to dogs with generalized seizures.

Conclusions and Clinical Importance

Seizure‐precipitating factors are common in dogs with idiopathic epilepsy, and the nature of these factors is consistent with those of human patients. Aside from antiepileptic medication, acknowledging and avoiding seizure‐precipitating factors could help veterinarians achieve better treatment outcomes.