Klüver-Bucy Syndrome
Klüver-Bucy syndrome is a neuro-behavioural syndrome associated with bilateral lesions in the anterior temporal horn or amygdala. Heinrich Klüver and Paul Bucy first described the syndrome in 1937 after experimental work where they removed rhesus monkeys' temporal lobes.1They found that the monkeys developed:
Visual agnosia - they could see, but were unable to recognise familiar objects or their use.
Oral tendencies - they would examine their surroundings with their mouths instead of their eyes.
Hypermetamorphosis - a desire to explore everything.
Emotional changes - emotion was dulled and facial movements and vocalisations were far less expressive. They lost fear where it would normally occur. Even after being attacked by a snake, they would casually approach it again. This was called "placidity".
Hypersexuality - a dramatic increase in overt sexual behaviour, including masturbation, and homosexual and heterosexual acts. They may even attempt copulation with inanimate objects.
The syndrome in humans is due to bilateral destruction of the amygdaloid body and inferior temporal cortex, most commonly due to herpes simplex encephalitis (HSE). It shares visual agnosia and loss of normal fear and anger responses in common with the monkey model but one also sees loss of memory with dementia, distractibility and seizures. The hypersexuality tends to be less overt than in the monkeys but may be public and unacceptable.
Clinical features
Note: we rarely, if ever, see the full syndrome in humans.
In adults:
Emotional blunting: there is a flat affect and poor response to emotional stimuli (placidity).
Hyperphagia: there is a strong compulsion to place objects in the mouth, probably to gain oral stimulation and to explore the object to counteract the visual agnosia, rather than due to hunger. Nevertheless, there is bulimia and there will be marked weight gain unless diet is restricted. Actions may include socially inappropriate licking or touching.
Visual agnosia: there is an inability to recognise objects or faces visually. This is also called "psychic blindness" ands may account for the oral compulsion.
Increased sexual behaviour: individuals with Klüver-Bucy syndrome lack social sexual restraint with profuse and inappropriate sexual activity.
In children:6
It usually follows herpes simplex encephalitis (HSE) and develops on regaining consciousness and activity.
Altered emotional behaviour, changes in dietary habits, hyperorality and hypersexuality have been reported as present in all, while psychic blindness and hypermetamorphosis occurred in only a few.
Marked indifference and lack of emotional attachment towards their family.
Apathy and easy distractibility are rare.
Bulimia and a strong urge to put items other than food into the mouth are common.
Hypersexuality presents as frequent holding of genitals, intermittent pelvic thrusting movements and rubbing of genitals to the bed on lying prone. Usually sexually inappropriate behaviour in children is taken as indicative of sexual abuse. There was no suggestion reported that they had been abused and it is thought that their ignorance of sex led to a different pattern from adults