Cognitive dysfunction syndrome (CDS) is a chronic, progressive disease characterized by neuronal loss and neuroaxonal degeneration.1,2 In dogs, CDS has some similarities to human Alzheimer’s disease in neuroanatomic pathology.3 Treatments include environment and behavior modification, comorbidity considerations, and medication for possible anxiety and agitation.
The prevalence of CDS in dogs and cats is fairly high. Reportedly, 28% of dogs 11 to 12 years of age and 68% of dogs 15 to 16 years of age show at least one sign associated with CDS.4 In laboratory settings, dogs begin showing impairment in specific learning and memory tasks as early as 6 to 8 years of age.5 The clinical presentation in cats is more ambiguous, although they may begin to show signs consistent with cognitive dysfunction at approximately 10 to 11 years of age. One study reported that 50% of cats older than 15 years of age had possible CDS.5,6
Related Article: House Soiling & Cognitive Dysfunction Syndrome
Screening patients 10 years of age or older as part of routine examination can allow for treatment to slow CDS progression or address signs that may distress patient and caregiver. Anxiety (eg, restlessness, fear or phobias, separation anxiety) can be a common sign of CDS. The most common signs in dogs are alterations in social interaction and a break in housetraining.7 Altered social interactions may reflect an increase in neediness (ie, a dog seeks the owner more often) or the opposite (ie, a dog appears more aloof and disinterested in engaging the owner). In cats, the most common signs are vocalization (often at night) and housesoiling without medical cause.8 One of the most troubling signs for caregivers is the potential change in sleep–wake cycles: patients may remain awake throughout the night and pace, whine, or vocalize. Patients may also show anxiety or fear (agitation) that may result from disorientation.
Classically, the signs of CDS in dogs have been described with the acronym DISH-A:
- Disorientation (eg, wandering, going to the hinged side of doors, appearing confused)
- Social Interaction changes
- Sleep–wake cycle changes
- Housetraining breaks (when previously housetrained)
- Activity level changes (decreased or increased)