Evaluation of Two Practical Tools to Assess Cognitive Impairment in Aged Dogs

Cognitive dysfunction syndrome is the most common cause of cognitive decline in aged dogs. Early diagnosis is crucial because the sooner treatment is implemented, the greater the chance of slowing the progression of the disease. Assessment tools to assess cognitive decline may differ depending on the environment in which the dogs live. The aims of this study were threefold, first, to describe two feasible methods to evaluate cognitive impairment in aged dogs living in different environments: (i) a Canine Cognitive Assessment Scale (CCAS) for dogs living in a home environment and (ii) a practical cognitive test (PCT) potentially useful for dogs not living in a home environment (NHE); second, to assess the effect of age on the outcome of both tools and, finally, to compare the results of the CCAS with those of the PCT. Both methods were found to be practical to perform. Age was found to significantly predict the score obtained by the CCAS (p = 0.0011) and the outcome of the PCT (p = 0.009). However, the reversal phase from the PCT did not significantly predict the outcomes of the CCAS (p = 0.97). Taken together, these findings suggest that the CCAS is a practical method to evaluate age related cognitive changes in owned dogs. The fact that the PCT has not been proven to be related with the CCAS calls into question the use of the PCT as a sensitive tool to assess cognitive impairment. Further studies in this field are suggested.

S100B protein and neuron-specific enolase as predictors of postoperative cognitive dysfunction in aged dogs: a case-control study

OBJECTIVE

Postoperative cognitive dysfunction (POCD) may be related to brain injury. S100B protein and neuron-specific enolase (NSE) have been investigated as potential biochemical markers of neural cell injury in animals and humans. This study aimed to investigate the association between POCD, brain injury and serum concentrations of S100B and NSE after periodontal surgery in aged dogs.

STUDY DESIGN

Prospective observational animal study.

ANIMALS

A total of 24 male and female dogs undergoing periodontal surgery.

METHODS

Dogs were separated into two groups based on age: control group, 10 dogs ≤ 8 years and aged group, 14 dogs > 8 years. Cognitive function was measured preoperatively and on the seventh postoperative day using the Canine Cognitive Dysfunction Rating scale and the Age-Related Cognitive and Affective Disorders scale. S100B protein and NSE serum concentrations were measured before and immediately after the surgery.

RESULTS

POCD was not observed after surgery in the present study. Serum concentrations of S100B and NSE were increased postoperatively in the control group but not in the aged group (p = 0.04 and 0.03, respectively). Preoperative S100B serum concentrations were significantly higher in the aged group (p = 0.01).

CONCLUSIONS

There was no association between POCD and high concentrations of S100B and NSE in dogs. However, increased postoperative serum concentrations of S100B and NSE were found in the control group after surgery, an effect that may indicate neural damage.

CLINICAL RELEVANCE

The results suggest that anesthesia and oral surgery are associated with higher postoperative serum concentrations of S100B and NSE in dogs ≤ 8 years old, which may indicate neural damage. Serum concentrations of S100B were elevated in aged dogs before anesthesia, a finding that might be related to chronic preoperative brain damage.