Autism and brain damage

If we go back to the general section on the brain and its functions we saw that

• The frontal lobe is associated with reasoning, higher level cognition, and expressive language. It appears that the temporal lobes directly interact with the frontal lobes in memorising and learning. In consequence, if the frontal lobe is injured, and even if the temporal lobes are spared, a child may demonstrate significant inability to learn or reason.  We have already seen that both are true of the autistic child.  About a third to a half of individuals with autism do not develop enough natural speech to meet their daily communication needs.  Differences in communication may be present from the first year of life, and may include delayed onset of babbling, unusual gestures, diminished responsiveness, and vocal patterns that are not synchronized with the caregiver. In the second and third years, autistic children have less frequent and less diverse babbling, consonants, words, and word combinations; their gestures are less often integrated with words.

Because the autistic child has such difficulty in learning new functions – whether behavioural or not, the few they do manage to learn tend to be repeated.  Thus autistic children repeat very simple learnt function such as hand flapping, making sounds, head rolling, or body rocking [although this may provide comfort]. 

Since learning is so very difficult for them, all new situations represent potential danger and they clearly feel enormous fear at not knowing what to do next.  This is when the emotion is expressed – the tantrums are expressing panic.  This also manifests itself as resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted and a longing for an unvarying pattern of daily activities, such as an unchanging diet or set of foods, or a dressing ritual. And they stick to activities they have mastered such as preoccupation with a single television program, toy, or game.

If you can imagine how frightened these children must be at times and how bewildered, presented with constant stimulation but having no armoury of function to deal with it, it is not surprising to find that this fear exhibits itself in self-injury, such as eye poking, skin picking, hand biting, and head banging. All of which tend to indicate a form of self-hatred at not being able to cope. A 2007 study reported that self-injury at some point affected about 30% of children with ASD.

• The back frontal lobe - At the back of the frontal lobe, near the central sulcus, lies the motor cortex. This area of the brain receives information from various lobes of the brain and uses the  information to carry out body movements.  Damage to this area is not likely to have any effect spiritually, but it is clear that there is damage to those with autism.  An estimated 60%–80% of autistic people have motor signs that include poor muscle tone, poor motor planning, and ‘toe walking’; deficits in motor coordination are pervasive across ASD and are greater in autism proper.

• The parietal lobe is located in the middle section of the brain and is associated with processing tactile sensory information such as pressure, touch, and pain. A portion of the brain known as the somatosensory cortex is located in this lobe and is essential to the processing of the body's senses.  Sensory abnormalities are found in over 90% of those with autism, differences are greater for under-responsivity (for example, walking into things) than for over-responsivity (for example, distress from loud noises)

• The temporal lobe is located on the bottom section of the brain. This lobe is also the location of the primary auditory cortex, which is important for interpreting sounds and the language we hear. Autistic children have problems in this area.  This portion of the brain is also heavily associated with the formation of memories.

If we now compare the left and right temporal lobes we can also see that there is the high probability that there is damage to both temporal lobes.

• Left temporal lobe -. damage involving the inferior temporal areas can moderately disrupt immediate and severely impair memory for verbal passages. Overall the findings of researchers have tended to confirm that the left brain not only processes the logical and language based side of input, but also stores it as well in memory.  But, in a pair of studies, high-functioning autistic children aged 8–15 performed equally well as, and adults better than, individually matched controls at basic language tasks involving vocabulary and spelling. Both autistic groups performed worse than controls at complex language tasks such as figurative language, comprehension and inference. As people are often sized up initially from their basic language skills, these studies suggest that people speaking to autistic individuals are more likely to overestimate what their audience comprehends.  So we have an interesting split here.  The memory for the words is in many autistic children undamaged, but the processing of that language – a function of the frontal lobe is deficient.

• Right temporal lobe - In contrast, right temporal damage  significantly impairs recognition memory for tactile and recurring visual stimuli such as faces, picture and designs.  Older children and adults with ASD perform worse on tests of face and emotion recognition.

If we look at the levels on the temporal lobe:

• The superior temporal sulcus is the sulcus separating the superior temporal gyrus from the middle temporal gyru. It is involved in the perception of where others are gazing and is thus important in determining where others' emotions are being directed.  Damage here will have little effect spiritually, but there is some evidence that this is damaged in the  autistic person

• The medial temporal lobe (MTL) becomes activated during memory recognition and recall and it is clear that it is the MTL that is a primary source for memory processing.  The autistic child shows problems in this area indicating that there is damage here.

• The Inferior temporal lobe  is connected with temporal order – the ordering of perceptions in a sequence.  Hence it is likely that the inferior temporal lobe is involved in the laying down of perceptions or even some perception processing.  The autistic child is obsessed with order and sequence, which rather implies that their Inferior temporal lobe remains undamaged.  Autistic adults can often review complex scenes from their past, but often have difficulty describing such scenes because of language difficulties.  We saw that inferior temporal lobe is the seat of perfect recall from perceptions as opposed to from memory.

A little boy with autism and the toys he has arranged methodically in a row

Photo from Wikipedia