Deep Brain Stimulation and Cluster Headaches

Cluster headaches are one of the most distressing types of headache that anyone can experience. The pain is typically excruciatingly intense and on one side of the head; it can come on without warning and occur daily, lasting between quarter of an hour and three hours. In really bad cases, the person affected by cluster headaches can have repeated attacks – sometimes 5, 6 or more each day.

As you might expect, this condition is extremely disabling. Once a headache is in progress the person simply cannot function; they can no longer work, drive or engage in social situations and must retreat to lie down in a dark room. People who have been asked to describe the pain have said it is the worst pain they have every felt – female sufferers all agree that the pain of a cluster headache attack is more intense and painful that the height of labour contractions.

Current Treatment for Cluster Headaches

There are some treatments for cluster headaches that work for some people but all have their problems. Ordinary pain killers such as paracetamol and aspirin are no use because they often take longer to work than the headache pain lasts. Some of the drugs used to treat severe migraines – such as ergotamine (no longer used so much because of its side effects) and sumatriptan – do work for some people when taken just as an attack starts. Sumatriptan needs to be injected to work quickly enough to provide relief.

Other drugs such as lithium carbonate and the calcium channel blocker verapamil can also be used but the most successful drug therapy specifically for people with cluster headaches is methysergide maleate. This helps around six in ten people with this condition. The drug relieves attacks but can also be taken regularly to minimise the number of attacks that occur. None of these drugs are without side effects and many people with cluster headaches worry about the long term effects of taking them regularly and over a long period.

Surgery for Cluster Headaches

As a last resort, surgery is carried out to disable the fifth cranial nerve, which is thought to be the main nerve involved in cluster headache pain. When the cells in this nerve are destroyed using a heated needle, pain can no longer be transmitted via the trigeminal nerve and headache frequency can reduce. However, the procedure needs a very skilled surgeon to precisely locate the right cells.

Brain Stimulation and Cluster Headaches

A new technique has been developed in the UK at the National Hospital for Neurology and Neurosurgery, which is based in London. Early trials are currently in progress but the results so far look very encouraging.

The idea of brain stimulation is to target the centre in the brain that is the source of the pain signals in cluster headaches, rather than trying to stop them by destroying the nerve. The sensation of pain is generated by electrical disturbances in the hypothalamus, which is deep in the brain. By drilling into the skull and placing an electrode made from titanium right inside the hypothalamus, it is then possible to stimulate the hypothalamus using a simulator that is implanted under the skin of the chest.

When the stimulator is activated, it sends electrical impulses into the electrode and these generate blocking signals directly in the hypothalamus, preventing the disturbances that set off a cluster headache. So far, around 6 in 10 people with cluster headaches seem to benefit but the side effects are not as bad as with drug therapy. The electrical stimulation is highly targeted, so there are no effects on other parts of the body. The brain does not seem to be damaged by the electrode.

More Trials in the Future

The doctors responsible for pioneering this technique are now planning larger trials – only 80 people have received the brain implant so far. These will be required to fully demonstrate the benefits of the treatment so that the National Institute of Clinical Excellence (NICE) can consider if this is a treatment that should be offered within the National Health Service (NHS). The one drawback of the technique is that the skills needed to implant the electrode, and the intricate brain operation necessary, make it an expensive procedure. If the NHS cannot provide it, people with cluster headaches who want the operation done privately could face a bill of £30 000.