In one particularly interesting section, they discuss research on using neuroimaging to replace the Wada test – the procedure where the barbiturate drug sodium amobarbital is injected into the carotid artery to temporarily disable one hemisphere of the brain.
This is used in people about to undergo neurosurgery to remove a brain area that may be causing uncontrollable and dangerous epileptic seizures.
It is particularly important to know which hemisphere of the brain is most involved in language, so the surgeons know where to tread carefully to make sure the patient’s language ability isn’t damaged.
Obviously, injecting strong sedative drugs directly into major brain arteries has its risks; both to the patient (there is a small risk of stroke), and the clinicians – such as the occasional patient going bezerk on the drugs.
This has led researchers to try and replace the Wada test with something less invasive and somewhat safer, namely scanning the brain with fMRI (e.g. see this pdf).
The technology is still being developed, however, as the results of the Wada test and an fMRI scan don’t always match, although new developments are improving the accuracy of these brain scan techniques as time goes on.