Month: December 2008

I’ve just found this fascinating article on how legendary neurologist Gordon Holmes discovered how the visual cortex represents visual space after studying World War One soldiers who had experienced bullet or shrapnel wounds to the brain.

World War One taught us a great deal about neuropsychology largely due to developments in weapons technology. The German Mauser was an accurate rifle that used small bore ammunition where previous conflicts had largely used single shot rifles mostly designed so a group of soldiers could create a ‘wall of lead’, rather than a carefully aimed shot.

Developments in shell technology also meant that high explosives could be launched with reasonable accuracy into groups of soldiers causing significant shrapnel injuries.

However, both the rifles and shells were at a stage where the velocity of either a bullet or a piece of shrapnel was relatively slow by today’s standards, meaning that the brain was not additionally damaged by shock waves, like with modern munitions.

In other words, they could create small discrete areas of brain damage that left the rest of the brain largely unaffected.

The British Brodie helmet, which sat like a tin bowl on the top of the head, left the lower parts of the head, and hence the brain, exposed. This meant a significant number of injuries were to the visual cortex, at the rear of the brain.

Neurologist Gordon Holmes studied the link between small lesions to this area and which areas of vision had been lost in soldiers coming back from the front.

The diagram on the right is one of his drawings where he demonstrated the link between a very specific shrapnel wound and a crescent-like area of blindness in the visual field. The full diagram is in the article where he also shows how it affected the right eye.

These studies taught us that the visual cortex is ‘retinoptically mapped’, meaning that each part of the cortex corresponds to a specific area of vision. It also taught us that some brain areas can be very specifically localised to certain functions, whereas previously we’d only known of very general connections between function and brain area.

The article, published in opthamology journal Documenta Ophthalmologica, describes Holmes’ wartime experiences, his discoveries and something of his character.

It also contains this curious episode, related by one of his junior doctors, largely notable for the fact that they hid a blonde beauty queen in a bathroom on the hospital ward to boost morale of the medical house officers.

Holmes had no time for neurotics and hysterics, and less … for psychoanalysis … [Once] In the ward there was a blonde bombshell of twenty-one with mild tension headaches. She was as pretty as a picture, plump as a partridge, who the previous year had been the Daily Mirror Bathing Beauty Queen. The first time I took Holmes around, he stopped at the foot of the bed and said ‘Who is this woman?’ I explained, whereupon he jerked his thumb towards the door and said ‘Get rid of her’.

Of course, I did nothing of the sort, for she was useful in keeping up the morale of us house officers. A week later he came around and said ‘I thought I told you to get that woman out of here?’ Yet another week passed. On this occasion I got the Sister of the ward to hide the patient in the bathroom during the ward round. Standing at the foot of the empty bed, Holmes paused, then said to me ‘Look here, my boy, either she leaves the hospital or you do – and I don’t care which.

Link to ‘Gordon Holmes, the cortical retina, and the wounds of war’.
Link to DOI for same.

Discover magazine has a thought-provoking article on the question of whether ‘shaken baby syndrome’, claimed to be a specific type of brain damage that occurs to young children if shaken, actually exists as a useful syndrome. If it doesn’t, it might not only be a medical miscategorisation but also a legal disaster that may have falsely convicted innocent families of child abuse.

Critics argue it’s a bit like calling a broken nose ‘punched in the face syndrome’. The label is for a non-specific injury but which automatically leads us to assume that an aggressor must exist.

Once a doctor says that an infant must have been shaken, it triggers a hunt for the shaker. In one diagnostic step, the legal system is brought to bear on the baby’s family and anyone else near the infant at the time of the supposed shaking.

The symptomatic triad of bleeding between the brain and skull (known as subdural or subarachnoid hematomas), bleeding behind the retinas, and brain swelling is both the core of an SBS diagnosis and the point of departure for the syndrome’s skeptics. The medical proof that shaking alone can cause these internal head injuries is questionable, the skeptics say, when many other things, from infections to malnutrition to falls onto a hard surface, are known to be causes of similar symptoms in infants.

In contrast, supporters of the condition, which came to world-wide attention in the case of British nanny Louise Woodward, argue that shaking causes babies specific injuries that are unlikely to be triggered by anything else. The article quotes Eli Newberger, an assistant professor of pediatrics at Harvard Medical School:

‚ÄúBy the time I was asked to testify in the Louise Woodward case…there was a great deal of clinical understanding about [SBS-related] trauma,‚Äù Newberger says. ‚ÄúThe infant‚Äôs head is disproportionately larger in relation to the rest of its body than our heads are. A child can‚Äôt stop the to-and-fro excursions of the head with its neck. The brain bobbles about. The infant‚Äôs brain is softer than the adult‚Äôs.‚Äù…

Money, Newberger suspects, has brought otherwise good people over to what he and his colleagues call the “dark side,” doubting SBS. “I have never ceased to be amazed about what highly regarded, well published, scientifically informed doctors will do when they’re offered large amounts of money,” he says.

And indeed, experts on both sides seem to charge a great deal for their time.

The article walks us through some of the studies that have attempted to look at how many children with these symptoms show other signs of abuse, or have tried to simulate the damage with computer or physical models.

It’s a fascinating look at a syndrome I just took for granted as being widely validated and looks at the implications of the scientific work for the legal system, where incorrect diagnosis can lead to abusers going free or loving parents being jailed.

Link to ‘Does Shaken Baby Syndrome Really Exist?’.