A recent study has shown that elderly dogs with dementia experience similar sleep disruptions to humans with dementia. Researchers from North Carolina State University performed electroencephalography, or EEGs, on 28 elderly dogs to investigate whether brain-wave readings during sleep correlated with signs of cognitive decline.
The study revealed that dogs with more advanced dementia experienced more sleep disruptions and slept less overall than dogs with normal cognitive function. The dogs underwent two sleep sessions in the lab to record brain activity during a two-hour sleep period, with non-invasive techniques used to gather data. The researchers used sticky gel to affix electrodes to the dogs’ skulls, and the dogs were not sedated during the process.
The EEG measured four stages of sleep: wakefulness, drowsiness, NREM and REM. In NREM, the brain clears toxins, including the beta-amyloid proteins that are involved in diseases like Alzheimer’s. REM sleep is when dreams occur, and it is an essential stage for memory consolidation.
The researchers correlated the percentage of time spent in each sleep stage with the dogs’ scores on cognitive testing and the Canine Dementia Scale questionnaire, which was completed by the dogs’ owners to determine the severity of their cognitive decline. The study found that the higher the dog’s dementia score, the less time they spent in NREM and REM sleep.
In addition to experiencing shorter sleep times, dogs with advanced dementia exhibited more brain activity during sleep that was similar to wakefulness, meaning that their brains were not truly asleep.
The research forms part of an ongoing clinical trial on canine aging and cognition at NC State, with the researchers hoping to establish baselines for identifying cognitive decline in dogs. The study shows that EEG signatures are useful indicators of canine cognitive dysfunction and further establishes the dog as a model for Alzheimer’s disease.
The researchers hope that the findings of the study can lead to early diagnosis and intervention for elderly dogs with signs of cognitive decline, as well as directing choices for treatment development in humans.