A comparison of 2 screening questionnaires for clinical assessment of canine cognitive dysfunction

Comparing standard screening questionnaires of canine behavior for assessment of cognitive dysfunction

Background

Canine cognitive dysfunction (CCD) is a common, yet underdiagnosed neurodegenerative disease affecting older dogs. Treatment is most effective when started early, so identifying mild cognitive decline in the earlier stages of the disease is considered important.

Hypothesis/objective

To compare the results of three different standard screening questionnaires [Canine Dementia Scale (CADES), Canine Cognitive Assessment Scale (CCAS), and Canine Cognitive Dysfunction Rating Scale (CCDR)] for CCD diagnosis. Trainability, pain sensitivity, and fear were additionally assessed with the Canine Behavioral Assessment and Research Questionnaire (C-BARQ) in order to evaluate associations between the three dementia scales and behavior.

Methods

An online survey containing all the mentioned questionnaires was designed for and distributed among owners of elderly dogs.

Results

Data from 597 dogs were analyzed. Overall, the scores of the three CCD questionnaires correlated well with each other, especially those of the CADES and CCAS. The CADES was more sensitive in identifying dogs with already mild to moderate cognitive impairment, while the others classified them as still undergoing normal aging. CCD scores increased for all questionnaires with age with spatial orientation being a key feature in CCD development. Trainability assessed with the C-BARQ decreased significantly with severity of CCD signs, while pain sensitivity increased. Fear and anxiety was pronounced in animals with mild but not with severe CCD. These associations based on the C-BARQ were more clearly observable in relation to CADES and CCDR than CCAS.

Conclusion/clinical relevance

The choice of screening questionnaire impacts the evaluation of cognitive status and severity of CCD. Thresholds for severity classification differ significantly and may have an impact on reliable assessment. Further longitudinal studies are required to determine which of the questionnaires investigated in this study is best suited for early detection of CCD.

2023 AAHA Senior Care Guidelines for Dogs and Cats

Veterinary professionals are taught to recognize that "old age is not a disease." However, clients may have the perception that older dogs and cats undergo an unavoidable physical, mental, and behavioral decline attributable simply to old age. The veterinary team's role includes providing medical care and support to senior pets to maintain their quality of life, as well as supporting and educating clients on proper senior animal care and addressing any misconceptions about the aging process. These Guidelines describe a systematic approach to the healthcare of the senior pet that is based on an evidence-guided assessment of both healthy and unhealthy canine and feline patients. By using evidence-guided medicine, which may include conventional and integrative approaches as well as environmental management for the senior pet, the patient's quality of life can be enhanced and potentially extended during this vulnerable life stage. Developing a senior program for the veterinary practice requires appropriate training of the entire healthcare team and includes a robust client education program that focuses on the wellbeing of the senior pet. Palliative and hospice care should be included in the education and information provided for both the veterinary team and the families of senior pets.

Autologous skin-derived neural precursor cell therapy reverses canine Alzheimer dementia-like syndrome in a proof of concept veterinary trial

BACKGROUND

Older companion dogs naturally develop a dementia-like syndrome with biological, clinical and therapeutic similarities to Alzheimer disease (AD). Given there has been no new safe, clinically effective and widely accessible treatment for AD for almost 20 years, an all-new cell therapeutic approach was trialled in canine veterinary patients, and further modelled in aged rats for more detailed neurobiological analysis.

METHODS

A Phase 1/2A veterinary trial was conducted in N = 6 older companion dogs with definitive diagnosis of Canine Cognitive Dysfunction (CCD). Treatment comprised direct microinjection of 250,000 autologous skin-derived neuroprecursors (SKNs) into the bilateral hippocampus using MRI-guided stereotaxis. Safety was assessed clinically and efficacy using the validated Canine Cognitive Dysfunction Rating Scale (CCDR) at baseline and 3-month post treatment. Intention to treat analysis imputed a single patient that had a surgical adverse event requiring euthanasia. Three dog brains were donated following natural death and histology carried out to quantify Alzheimer pathology as well as immature neurons and synapses; these were compared to a brain bank (N = 12) of untreated aged dogs with and without CCD. Further, an age-related memory dysfunction rat model (N = 16) was used to more closely evaluate intrahippocampal engraftment of canine SKN cells, focusing on mnemonic and synaptic effects as well as donor cell survival, neurodifferentation and electrophysiologic circuit integration in a live hippocampal slice preparation.

RESULTS

Four out-of-five dogs improved on the primary clinical CCDR endpoint, three fell below diagnostic threshold, and remarkably, two underwent full syndromal reversal lasting up to 2 years. At post mortem, synaptic density in the hippocampus specifically was nine standard deviations above non-treated dogs, and intensity of new neurons also several fold higher. There was no impact on AD pathology or long-term safety signals. Modelling in aged rats replicated the main canine trial findings: hippocampally-dependent place memory deficits were reversed and synaptic depletion rescued. In addition, this model confirmed donor cell survival and migration throughout the hippocampus, neuronal differentiation in situ, and physiologically-correct integration into pyramidal layer circuits.

CONCLUSIONS

With further development, SKN cell therapy may have potential for treating carefully chosen AD patients based on neurosynaptic restoration in the hippocampus.

Sustained Gaze Is a Reliable In-home Test of Attention for Aging Pet Dogs

Canine Cognitive Dysfunction Syndrome (CCDS) is a syndrome of progressive cognitive decline comparable to Alzheimer's Disease. The sustained gaze test captures attention loss associated with CCDS in laboratory settings, and adapting the sustained gaze test for use by owners at home could greatly increase the data generated on CCDS. We hypothesized that it would be feasible for owners to perform the sustained gaze test at home, and that results would be reliable over repeated trials. Training materials were developed and dog owners underwent training and performed the test in triplicate at weekly intervals for 3 weeks. Gaze videos and a CAnine DEmentia Scale (CADES) questionnaire were submitted each week. Videos were examined for inclusion and duration of gaze was recorded. One observer repeated video assessments twice, 1 week apart; five different observers assessed videos once. Outcome measures included the relationship between CADES and gaze duration, test-retest reliability of owner-performed sustained gaze testing, and intra- and inter-rater reliability. Twenty dogs aged 7–15.5 years completed testing. The majority of videos were acceptable (162/183). Within dog test-retest reliability was excellent (ICC = 0.96). Intra- and interobserver reliability for determining video validity for inclusion were substantial (k = 0.76 and 0.78, respectively); for duration of gaze these were excellent (ICC = 0.99 and 0.96, respectively). Gaze duration was significantly associated with CADES (p = 0.0026). We conclude that owners can perform the sustained gaze test at home and that data generated are reliable and correlate to CADES, a validated measure of dementia.

Neural Derivates of Canine Induced Pluripotent Stem Cells-Like Cells From a Mild Cognitive Impairment Dog

Domestic dogs are superior models for translational medicine due to greater anatomical and physiological similarities with humans than rodents, including hereditary diseases with human equivalents. Particularly with respect to neurodegenerative medicine, dogs can serve as a natural, more relevant model of human disease compared to transgenic rodents. Herein we report attempts to develop a canine-derived in vitro model for neurodegenerative diseases through the generation of induced pluripotent stem cells from a 14-year, 9-month-old female West Highland white terrier with mild cognitive impairment (MCI). Canine induced pluripotent stem cells-like cells (ciPSCLC) were generated using human OSKM and characterized by positive expression of pluripotency markers. Due to inefficient viral vector silencing we refer to them as ciPSCLCs. Subsequently, the ciPSCLC were subjected to neural induction according to two protocols both yielding canine neural progenitor cells (cNPCs), which expressed typical NPC markers. The cNPCs were cultured in neuron differentiation media for 3 weeks, resulting in the derivation of morphologically impaired neurons as compared to iPSC-derived human counterparts generated in parallel. The apparent differences encountered in this study regarding the neural differentiation potential of ciPSCLC reveals challenges and new perspectives to consider before using the canine model in translational neurological studies.

Change in the plasma proteome associated with canine cognitive dysfunction syndrome (CCDS) in Thailand

BACKGROUND

Canine cognitive dysfunction syndrome (CCDS) is a progressive neurodegenerative disorder found in senior dogs. Due to the lack of biological markers, CCDS is commonly underdiagnosed. The aim of this study was to identify potential plasma biomarkers using proteomics techniques and to increase our understanding of the pathogenic mechanism of the disease. Plasma amyloid beta 42 (Aβ₄₂) has been seen to be a controversial biomarker for CCDS. Proteomics analysis was performed for protein identification and quantification.

RESULTS

Within CCDS, ageing, and adult dogs, 87 proteins were identified specific to Canis spp. in the plasma samples. Of 87 proteins, 48 and 41 proteins were changed in the ageing and adult groups, respectively. Several distinctly expressed plasma proteins identified in CCDS were involved in complement and coagulation cascades and the apolipoprotein metabolism pathway. Plasma Aβ₄₂ levels considerably overlapped within the CCDS and ageing groups. In the adult group, the Aβ₄₂ level was low compared with that in the other groups. Nevertheless, plasma Aβ₄₂ did not show a correlation with the Canine Cognitive Dysfunction Rating scale (CCDR) score in the CCDS group (p = 0.131, R² = 0.261).

CONCLUSIONS

Our present findings suggest that plasma Aβ₄₂ does not show potential for use as a diagnostic biomarker in CCDS. The nano-LC-MS/MS data revealed that the predictive underlying mechanism of CCDS was the co-occurrence of inflammation-mediated acute phase response proteins and complement and coagulation cascades that partly functioned by apolipoproteins and lipid metabolism. Some of the differentially expressed proteins may serve as potential predictor biomarkers along with Aβ₄₂ in plasma for improved CCDS diagnosis. Further study in larger population-based cohort study is required in validation to define the correlation between protein expression and the pathogenesis of CCDS.

Novel Diagnostic Tools for Identifying Cognitive Impairment in Dogs: Behavior, Biomarkers, and Pathology

Canine cognitive dysfunction syndrome (CCDS) is a progressive neurodegenerative disorder in senior dogs that is mainly associated with decreased ability to learn and respond to stimuli. It is commonly under-diagnosed because behavioral changes are often attributed to the natural process of aging. In the present study, we used for the first time a comprehensive approach enabling early diagnosis of canine patients with mild cognitive disorders (MiCI). We included CAnine DEmentia Scale (CADES) questionnaires, biochemical parameters, and biomarkers in blood serum, and correlated them with post-mortem histopathological changes. The CADES questionnaires enabled us to identify MiCI dogs developing changes mainly in domains corresponding to social interaction and spatial orientation, which seems to be crucial for delineating early cognitive disorders. Biochemical analyses in these dogs showed slightly elevated liver enzyme parameters (AST and ALT) and significantly decreased sodium and chloride levels in blood serum. Furthermore, we describe for the first time a significant increase of neurofilament light chain (NFL) in blood serum of MiCI dogs, compared to normal aging seniors and young controls, but no changes in TAU protein and amyloid-β (Aβ42) peptide levels. In canine brains with cognitive impairment, amyloid plaques of mainly diffuse and dense types were detected. Furthermore, activated microglia with amoeboid body and dystrophic processes occurred, in some cases with spheroidal and bulbous swellings. On the other hand, no TAU pathology or neurofibrillary tangles were detected. These results suggest that a combination of CADES questionnaire mainly with CNS injury biomarker (NFL) and with biochemical parameters (ALT, AST, Na, and Cl) in blood serum may predict CCDS in senior dogs.

Avaliação diagnóstica na síndrome disfunção cognitiva canina

RESUMO O objetivo do presente estudo foi avaliar o questionário observacional e os testes de reatividade como forma de triagem e diagnóstico da disfunção cognitiva em cães idosos. Foram estudados 10 cães acima de sete anos, que apresentavam queixas comportamentais. Foi utilizado questionário que abordava questões comportamentais, como desorientação, atividade, interação socioambiental, alterações no padrão do sono e casa-sujidade. As respostas foram convertidas em pontuações, cujo somatório classificou o cão com disfunção cognitiva canina (DCC), ou borderline (BL), ou sem alterações comportamentais (SAC). Logo depois, foram realizados, em todos os cães, os seguintes testes cognitivos: open field, curiosidade, interação com humano e com espelho. Pela avaliação do questionário, foi determinado que dois cães tinham DCC, três eram BL, cinco eram SAC. Os cães classificados com DCC tinham idade superior aos demais e apresentaram alterações em todos os testes de reatividade, enquanto os cães BL apresentaram alterações em dois testes de reatividade e os SAC não apresentaram alterações. Conclui-se que, com o aumento da expectativa de vida canina, o questionário observacional foi um instrumento de triagem para a identificação dos cães classificados com DCC, BL e SAC, e os testes de reatividade como um método inovador para identificar o verdadeiro estado cognitivo dos pacientes idosos.