Emotions and the brain: linking affective disorders to brain regions.

THE LANCET Neurology Vol 1 June 2002 http://neurology.thelancet.com 80 If you respond to the question “what is apathy?” by saying “I don’t know and I don’t care”, you’ve got the correct answer. But if you didn’t get this joke, you may be suffering from impaired humour appreciation, according to research presented at this year’s Rotman Research Institute Conference (Toronto, ON, Canada; March 25–26). Apathy is sometimes jokingly referred to as “the get-up-and-go that got up and went”, Robert van Reekum (University of Toronto, ON, Canada) told delegates. Nevertheless, apathy is important both clinically and for research purposes, he argued, because it contributes to a number of adverse outcomes across a number of ailments. The prevalence of apathy is around 60% in patients with traumatic brain injury and in outpatients with Alzheimer’s disease—it is even higher among nursing-home residents. However, somewhat surprisingly perhaps, only about 50% of depressed patients suffer from apathy. According to van Reekum, apathy has been associated with neurological dysfunction in limbic and frontal subcortical regions, and reduced activity in the anterior cingulate has been implicated as a causative factor by three separate studies. There is some evidence that people who have a stroke or develop Alzheimer’s disease become more apathetic as they age. “But otherwise there is a weak correlation between age and apathy, so apathy is not an inevitable consequence of ageing”, he noted. While ageing may not necessarily lead to apathy, getting old does seem to result in some impairment of humour appreciation, according to a recent study by Donald Stuss (University of Toronto, ON, Canada) and colleagues. The researchers compared the performance of 20 elderly participants (mean age 73 years) with that of 17 younger individuals (mean age 29 years) on verbal and nonverbal tests of humour. They found that the elderly participants made significantly more errors in the “joke completion test” and in the “cartoon appreciation task”, suggesting that they had some trouble understanding humour. The errors made by the older participants were similar to errors made by patients with right frontal lobe lesions in a previous study. Based on that study, the investigators concluded that “damage to the right frontal lobe impairs the ability to appreciate humour and to demonstrate humorous reactions”.