Epilepsy is a neurological condition characterised by repeated seizures. Seizures are caused by electrical activity in the brain, although may appear differently from person to person (not all seizures involve convulsions, despite what you might think).
As with many conditions there is not a single cause that can be identified as a precursor to epilepsy. Genetics (a mutation in the KCNC1 gene has recently been identified as a cause of a progressive inherited form of epilepsy – Muona et al 2015), brain tumours, or head injuries, and the cause of many patients’ epilepsy remains unknown. Several studies have shown that you are more likely to develop epilepsy after a head injury e.g. Christensen et al (2009) found that people were 2% more likely to develop epilepsy after a mild head injury. This rose to 7% more likely following a severe head injury, with risk also increasing slightly with age.
The image below is taken from the EFEPA and shows what to do if someone is having a seizure:
As mentioned earlier there are different types of epileptic seizures which depends on which part of the brain they originate in. Seizures can be classified by how much of the brain is affected: partial/focal seizures (when only a small part of the brain is affected) or generalised (if most of the brain, or all of it, it affected).
Focal seizures can also originate in different parts of the brain, with the temporal lobe being the most comment (epilepsy.com). The temporal lobe is the part of the brain above your ear, and is responsible for processing hearing, and our memories (this is simplified – it does a bit more than this!). Therefore, one of the common features of temporal lobe epilepsy is memory disturbances (Ko et al, 2013). The famous patient H.M.’s amnesia was caused by an operation to remove the source of his severe temporal epilepsy – this was carried out in the 50s before brain functions were accurately known and too much of the medial temporal lobe was taken away. This destroyed part of the hippocampus, the structure in the brain responsible for memory processing. Due to the nature of his amnesia, he was probably one of the most studied individuals ever in psychology. See this post for more on H.M. and memory research. Operations are carried out to remove part of the temporal lobe in patients now with much better outcomes!
The second most common is frontal lobe epilepsy, where seizures originate in the front part of the brain. They often occur during sleep, and can affect the motor areas of the brain, leading to problems with motor skills (e.g. Beleza & Pinho, 2011). If patients are not eligible for surgery to remove the specific part of the brain responsible for the seizures, anti-convulsive medication and electrical brain stimulation can be helpful in reducing symptoms (Kellinghaus & Luders, 2004).
Hi everyone, I hope you liked my last post on how children develop a theory of mind – this post follows on, and talks about children with autism (if you haven’t read that post, find it here https://freudforthought.wordpress.com/2015/08/06/theory-of-mind/).
Autism is a neurodevelopmental disorder, which has a prevalence of 60 per 10,000 children under 8 in the UK (Baird et al, 2000). Characteristics of autism include impairments in social interactions, communication, and imaginative behaviours. Also, individuals with autism tend to like to stick to routine, and can become distressed if their routine changes. However, autism is a spectrum, and sufferers can have a range from very mild, to severe impairments. For example, the disorder formerly known as Asperger’s Syndrome had all the characteristics of autism, but without the language difficulties (however this is now no longer recognised as a separate disorder).
Criteria for social impairments include lack of eye contact during interactions, and the lack of voluntarily sharing interests and enjoyment with others. Communication impairments include a delay of language development, and a lack of varied pretend play. Finally, examples of repetitive behaviour include sticking to rituals, and a preoccupation with the parts of objects. As mentioned in my last post, some of these behaviours can be explained by deficits in a theory of mind, which is a theory proposed by Baron-Cohen et al.
As well as the traditional theory of mind tasks, they also carried out more advanced experiments, called ‘reading the eyes’ tasks. In these, adults with autism were shown pictures of people’s eyes, and had to work out the emotion the eyes were showing. They found that autistic participants made more errors than controls without the disorder. However, it is worth noting that this task is challenging to normally developed adults – see how you get on from the picture below!
One other interesting thing about autism is that it is more common in males than females, with a 3:1 ratio. Baron-Cohen (2003) therefore outlined his theory that autism is an extreme form of the male brain. This theory states that everyone has either a male or female brain, regardless of their actual gender, with the male brain being better at systemising, and the female brain better at empathising. As autistic individuals can struggle showing empathy, and are generally interesting in how things work, he hypothesised that autism reflects the male brain. Despite the terms ‘male’ and ‘female’, he found that about 17% of men had a ‘female’ brain, with the same percentage of women having a ‘male’ brain. Many people also have a balanced brain, showing aspects of both.
I kind of get why he came to this conclusion, but I think that this theory is very oversimplified, and that there is actually no need for the terms ‘male’ or ‘female’ at all – especially as people can have aspects of both, and that the brain type has nothing to do with gender! Might be one theory to take with a pinch of salt…
But what do you think? Let me know in the comments and thanks for reading!
Visual Extinction is a condition caused by damage to the parietal lobe, and is similar, although distinct from Visual Neglect.
It is characterised by the ability to see stimuli in the opposite visual field to the brain damage, but only when there is no competition from other stimuli in the visual field on the same side as the brain damage. If there are stimuli in both visual fields then only the one which is projected to the intact side of the brain will be seen.
It is diagnosed using confrontation testing:
– the experimenter wiggles their left/right fingers or both in the air while sitting opposite the patient
– patient can detect each finger when they are presented separately
– however, if both are presented then they can only detect the finger on the left (assuming the right parietal lobe is damaged)
The video below shows a variation of this technique:
However, there are some circumstances in which extinction can be reduced.
Riddoch (2003) presented patients with pairs of objects, which were correctly or incorrectly presented for action. For example, a corkscrew pointing towards the cork in a wine bottle (correct), or at the bottom of the bottle (incorrect).
The results showed that they were better at reporting both items when they were correctly presented for action. When one item was extinguished, they were more likely to report the active item, even if it is in the impaired visual field.
Therefore, which object they reported was influenced by the interaction between them.
This finding was important as it suggests that extinction occurs quite late, in higher-order visual areas and there is some unconscious processing of extinguished items.
Like Neglect, extinction can also occur in motor actions, not just vision.
For example, several case studies have shown that patients can use both arms equally well separately, but become much worse at using their bad arm when doing so at the same time as the good arm.
Hope you enjoyed this post – don’t forget to check back soon for more!