Feline Cognitive Dysfunction

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Overview

Feline cognitive dysfunction (FCD) leads to an overall progressive decline in cognitive function and increase in brain pathology[1][2][3][4][5][6][7][8]. This can affect memory, capacity for learning, awareness and visual and audio perception. It can lead to various symptoms including disturbance in sleep patterns, a reduction in activity, confusion. Past learned habits become forgotten, for example the location of food and water and litter boxes and cats suffer from an increased level of anxiety and inclination to behave aggressively. Social relationships with both other animals and humans can also be affected. In general FCD is less frequently reported in cats than dogs. It is thought that FCD affects 50% of cats over fifteen years old and approximately 28% between the ages of eleven and fourteen[9]. Although clinical signs in cats generally seem to become evident at around ten to eleven years old, neurone in the caudate nucleus start to show functional changes by six-seven years of age[10][11][12].

Signs and Diagnosis

A complete medical and behavioural history is essential for the accurate diagnosis of FCD, this is especially important in older animals. This should be accompanied by a laboratory work up, as well as a thorough physical examination with special consideration of neurological conditions. As with all behavioural disorders it is important to ensure that any medical causes for unusual behaviour are ruled out. Medical conditions which could cause behaviour similar to that of FCD include:

  • Arthritis
  • Dental pain
  • Thyroid dysfunction
  • Diabetes mellitus
  • Neoplasms
  • Gastrointestinal conditions
  • Reduced sight and/or hearing
  • Urinary tract disease
  • Hepatic disease
  • Hypertension
  • Neurologic conditions, including neoplasms, motor and sensory deficits
  • Infectious causes, including FIV, FLV
  • Stress

Although all medical causes for FCD must first be excluded and if present treated, their presence does not necessarily eliminate the simultaneous existences of FCD.

Behaviours which may be linked to FCD include:

  • Reduced activity
  • Moves around the home environment less, performs less grooming and eats less
  • Unusual sleeping patterns
  • Sleeping longer during the day, waking up at night, restless when asleep, increased vocalisation at night
  • Disorientation
  • Gets lost, even in familiar places, staring either at specific things or just generally, aimless wandering, inability to find way around or over objects.
  • Memory and learning
  • Inappropriate elimination outside litter tray, including in sleeping area or near food. May be unable to recognise people or pets.
  • Social behaviour
  • Decreased interest in being stroked, or interacting with people or other animals or becomes increasingly dependent and doesn't like being alone.
  • Anxiety
  • Restlessness, increaesed vocalisation and general irritability.

Treatment

Most treatment for FCD is based around providing a stable environment and fixed routine for the cat in question. No drugs are licensed to treat FCD, however selegiline[13] and propentofylline are sometimes used unlicensed. Although these drugs have not managed to gain approval for treatment of cognitive disorders in humans studies have found selegiline improves symptoms related to canine cognitive function[14][15]. Anti-anxiety medications are also sometimes prescribed. There is a shortage of clinical evidence backing the efficacy of dietary and supplement use, however diets high in antioxidants, arginine, B vitamins and fish oils are thought to improve learning and recollection of learned habits in older cats. Other neutraceutical supplements specifically aimed at maintaining and improving cognitive function are also available and these are contain antioxidants, vitamins, carnitine, phosphatidylserine and fatty acids.

Treatment and management approaches to specific behavioural aspects of FCD

  • Inappropriate elimination: This particular sign has various potential medical causes, so these must be ruled out. Increasing the number of litter trays available, either on different floors or in different rooms which are obvious to the cat and easily accessible (without high edges or high up) may help avoid house soiling problems.
  • Disorientation: Ensure that locations of food, water, litter trays are constant and that the cat's daily routine is maintained the same as much as possible. If a cat is extremely disorientated or confused it can help to reduce the area accessible to the cat, so it can find its way around more easily.
  • Unusual sleeping patterns: Loss of eyesight and hearing may affect the cat's depth of sleep. Encourage activity during the day and evening through play so the cat is more likely to sleep at night. Anxiety associated with the dark or separation from owners at night may be improved with anti-anxiety medications.
  • Exaggerated Vocalisation: Vocalisation is usually linked to some form of anxiety, so it is important to try and establish the cause of this anxiety and then address it, by either adjusting the environment, using pheromones to try and help calm and reassure the cat and encouraging activity during the day to the cat is more likely to be tired and sleep at night. In addition, if anxiety is severe, anti-anxiety medications can be used.
  • Reduced activity: The use of a specialised diet for elderly felines may help stimulate activity and mental function[16].
  • Social behaviour: If there are other animals in the household, provide various sleeping areas so the older cat is able to find a safe place to rest if it does not want to interact.

Changes to the cats environment should be kept to an absolute minimum where possible. If changes are necessary they should be made very gradually and carefully, taking special care to reassure the cat so as not to induce stress which can cause the display of further symptoms of FCD[17].

Prognosis

Generally symptoms of FCD progress and are irreversible, however management and treatment measures can help to slow this gradual decline and occasionally allow cats to regain some of their lost mental function. In order to attempt to slow progression prompt intervention early on in the disease process is essential[1].

References

  1. 1.0 1.1 Landsberg GM, Hunthausen W, Ackerman L. The effects of aging on the behavior of senior pets. In: Handbook of behavior problems of the dog and cat. 2nd edn. Oxford; Saunders,2003: 269–304.
  2. Milgram NW, Head E, Weiner E, Thomas E. Cognitive functions and aging in the dog: acquisition of non spatial visual tasks. Behav Neurosci1994; 108:57–68.
  3. Cummings BJ, Satou T, Head E, et al. Diffuse plaques contain C-terminal A beta 42 and not A beta 40: evidence from cats and dogs. Neurobiol Aging1996; 17:653–59
  4. Cummings BJ, Head E, Afagh AJ, Milgram NW, Cotman CW. Beta-amyloid accumulation correlates with cognitive dysfunction in the aged canine. Neurobiol Learn Mem1996; 66:11–23
  5. Tapp PD, Siwak CT, Gao FQ, et al. Frontal lobe volume, function, and beta-amyloid pathology in a canine model of ageing. J Neurosci2004; 24: 8205–13.
  6. Borras D, Ferrer I, Pumarola M. Age related changes in the brain of the dog. Vet Pathol 1999; 36:202–11.
  7. Colle M-A, Hauw J-J, Crespau F, et al. Vascular and parenchymal beta-amyloid deposition in the aging dog: correlation with behavior. Neurobiol Aging 2000; 21:695–704.
  8. Salvin HE, McGreevy PD, Sachev PS, Valenzuela MJ. Underdiagnosis of canine cognitive dysfunction; a cross-sectional survey of older companion dogs. Vet J 2010; 184:277–81.
  9. Landsberg, G.M., Denenberg, S., Araujo, J.A., 2010. Cognitive Dysfunction in Cats: A Syndrome we Used to Dismiss as 'Old Age'. Journal of Feline Medicine and Surgery 12: 837
  10. Levine MS, Lloyd RL, Fisher RS, Hull CD, Buchwald NA. Sensory, motor and cognitive alterations in aged cats. Neurobiol Aging 1987; 8: 253–63
  11. Levine MS, Lloyd RL, Hull CD, Fisher RS, Buchwald NA. Neurophysiological alterations in caudate neurons in aged cats. Brain Res 1987; 401:213–30
  12. Harrison J, Buchwald J. Eyeblink conditioning deficits in the old cat. Neurobiol Aging 1983; 4:45–51
  13. Landsberg G. Therapeutic options for cognitive decline in senior pets. J Am Anim Hosp Assoc 2006; 42:407–13.
  14. Ruehl WW, Bruyette WW, DePaoli DS, et al. Canine cognitive dysfunction as a model for human age-related cognitive decline, dementia, and Alzheimer’s disease: clinical presentation, cognitive testing, pathology and response to l-deprenyltherapy. Prog Brain Res 1995; 106:217–25.
  15. Campbell S, Trettien A, Kozan B. A noncomparative open-label study evaluating the effect of selegiline hydrochloride in a clinical setting. Vet There 2001; 2:24–39.
  16. Cupp, C.J., Jean-Philippe, C., Kerr, W.W., Patil, A.R. & Perez-Camargo, G., 2006. Effect of nutritional interventions on longevity of senior cats. International Journal of Applied Research in Medicine 4, 34-50.
  17. Houpt, K.A. & Beaver, B., 1981. Behavioural problems of geriatric dogs and cats. Veterinary Clinics of North America: Small Animal Practice 11, 643-652.