10 Behaviour change – an introduction
Consciousness = alertness + awareness.
The goal when investigating a case of abnormal behaviour is to rule out organic neurological causes, e.g. metabolic encephalopathy, brain tumour, pain, before concluding that the behaviour change is psychological in nature.
In veterinary medicine, consciousness is generally regarded as a synonym for an alert mental state without taking into account what the animal may or may not be able to perceive, interpret or distinguish. If describing an altered consciousness (alertness or awareness), describe what is abnormal about the animal.
Normal behaviour is assessed against that occurring in others of the same species, breed and age group (Fig. 10.1). Consulting relevant textbooks is recommended.
Avoid anthropomorphism: withdrawing the upper lips horizontally to show canines and incisors has been given the description of smiling or grinning. It is done, often by Dalmatians, in response to a command or interaction with humans. It is described as a passive defensive behaviour or an anxiety-induced behaviour.
Sleep consists of cycles of rapid eye movement (REM) and non-rapid eye movement (NREM) phases (Table 10.1).
Seizures can be triggered in slow wave sleep.
are defined as intrusions of abnormal movement or behaviour into the sleep pattern. Intermittent paddling of limbs and lifting the head, with or without urination can occur in REM (also known as REM sleep behaviour disorder) and can easily be stopped by waking the animal. It could be mistaken for seizure activity.
A sudden attack provoked by waking or disturbing the dog during sleep is thought to be a manifestation of territorial aggression or vulnerability and has been termed sleep-associated aggression.
Sudden shock-like myoclonic jerks of limbs or body when falling asleep are called hypnic jerks or sleep starts. It occurs to an exaggerated degree in miniature wirehaired dachshunds with Lafora’s disease (familial myoclonic epilepsy).
Compulsive repetitive yawning (chasm)
as a sign of CNS disease, e.g. seizures, encephalitis, tumours of the fourth ventricle and frontal lobes, has not been reported in animals. There is reference to frequent yawning as a sign of otitis-media-interna but other deficits from pathology in this location are far more common. Perhaps head shaking and yawning in otitis media is a method for clearing a blocked eustachian tube.