Do dogs with cognitive dysfunction also have neurologic abnormalities?
Cognitive dysfunction syndrome (CDS) in dogs is thought to be similar to Alzheimer’s disease in people. And studies have revealed that people with Alzheimer’s disease not only have cognitive deficits, but neurologic deficits as well, such as impaired gait, restlessness, slowness, and, rarely, tremors. Thus far, studies investigating CDS in dogs have focused on cognitive signs only. So a study in a recent issue of the Journal of Veterinary Behavior examined whether dogs with CDS also exhibit neurologic signs. The owners of 21 dogs who brought their senior dogs (7 years of age or older) in for a routine check-up were asked to fill out a behavior questionnaire that identified whether the dogs were exhibiting signs of cognitive dysfunction. At the same time, the dogs underwent complete physical and neurologic examinations to look for any deficits.
Based on the owners’ responses to the questionnaire, seven of the dogs were considered to be aging normally, while 14 were considered to have CDS. On neurologic examination, nine dogs (six with CDS, three that were aging normally) had neurologic signs such as conscious proprioception deficits, spinal ataxia, and diminished patellar reflex. Four of the dogs with CDS displayed postural repetitive tremors in their hindlimbs. The researchers concluded that dogs with CDS were twice as likely to have neurologic signs as those without CDS. However, they thought the study population size was too small to state a definitive relationship and recommended that a similar study be performed on a larger scale. But these results may point to the notion that dogs suspected of having CDS should undergo neurologic examinations as well.
Golini L, Colangeli R, Tranquillo V, et al. Association between neurologic and cognitive dysfunction signs in a sample of aging dogs. J Vet Behav 2009;4(1):25-30.