The voice of the old cat


  • Age-related behavioural changes may occur in the cat
  • Different aspects of behaviour may be indicative of CDS
  • Symptoms of CKD and CDS may be closely related.

Age-related feline cognitive dysfunction syndrome (CDS) leads to behavioural changes in the affected cat. This includes inappropriate vocalisations, especially during the night. In a new study, the reasons for these unusual vocalisations were sought. Cat owners of affected cats were asked what they thought was the cause of these increased vocalisations. The cat owners questioned suspected disorientation of the cat as the main cause, but also attention seeking, food seeking or even pain.

Caregiver Burden

The researchers felt it was important to understand these behavioural changes in cats, especially from the owner’s point of view: CDS develops with age and can stress the cat owner and possibly also negatively affect the relationship with their cat. The relationship between cat and owner changes not only in interaction, but also because the cat owner perceives the cat’s unusual vocalisations as “crying” and accordingly worries about his cat when it “cries” more. Cat owners also regard the vocalisations as a restriction of their cat’s quality of life. This not only affects them emotionally, but they are also stressed and frustrated by their cat’s vocalisations. Stress and frustration of the cat owner are also reflected in the care of the CKD and can be a significant burden for the cat owner.


The behavioural changes in cats with CDS are grouped under the acronym VISHDAAL and include, but are not limited to,

  • increased vocalisation, especially at night,
  • altered interaction with the family (especially attention seeking), but also with other pets,
  • a change in the sleep/wake pattern,
  • loss of house-training,
  • spatial and temporal disorientation, e.g. forgetting the location of their litter box or that they have been fed,
  • Changes in activity, e.g. wandering aimlessly,
  • anxiety,
  • as well as learning and memory deficits.

These are changes that have been compared to Alzheimer’s disease in humans and can also affect old dogs. In cats, they usually appear from the age of 11 years.

Behavioural changes occur in cats from the age of 11 years.
Behavioural changes occur in cats from the age of 11 years.

The brain lacks oxygen

As far as is known at all, CDS is due to reduced cerebral blood flow (e.g. arteriosclerosis, and minor cerebral haemorrhages) and the accumulation of certain proteins in the cerebral cortex resulting in the loss of brain matter. High blood pressure and heart disease can further support these adverse brain changes and promote the loss of brain matter.


Due to good medical care, domestic cats also live significantly longer, so that already in 2011 about 1/5 of the US cat population was over 11 years old. From this age onwards, the behavioural changes associated with CDS increase. And the older the cat, the more behavioural changes it shows when it has CDS. Many older cats develop behavioural problems, but these are not associated with CDS. Instead, clinical signs are blamed or the behavioural changes are simply attributed to normal age-related behaviour.


Many other diseases can cause behavioural changes very similar to those of CDS. In particular, high blood pressure (= hypertension) or hyperthyroidism. Both are also related to chronic kidney disease in cats. So it is not surprising that the researchers also had cats with CKD in their study groups.


Increased vocalisation has been reported in Alzheimer’s disease, consisting of excessively loud and/or repetitive verbal utterances and constant requests for attention. In people suffering from Alzheimer’s disease or dementia, vocalisation can be triggered by a variety of stimuli, including the physical environment, stress, anxiety or social factors such as caregiver behaviour.

This bears similarities to the cats in the current study, where owner observations indicated that vocalisation appeared to be triggered by a need for attention, food, confusion or pain. Unusual vocalisation in a CKD cat may therefore be indicative of an additional condition such as CDS and should be monitored and assessed appropriately by professionals, particularly in the context of the other behavioural changes.


  • Cerna, P. / Gardiner, H. / Sordo, L. / Tornquist-Johnsen, C. & Gunn-Moore, D. A. (2020): “Potential Causes of Increased Vocalisation in Elderly Cats with Cognitive Dysfunction Syndrome as Assessed by Their Owners”; In: Animals,Vol. 10, 1092.