General Augusto Pinochet is reported to be suffering from extensive brain damage. BBC News Online examines the medical problems he is said to have suffered following several minor strokes.

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According to the Spanish press, General Pinochet suffered damage to the front and temporal lobes of the brain.

His main medical problems are said to be a peripheral diabetic neuropathology and a recent progressive cerebral-vascular injury.

The brain is made up of four lobes. The frontal and temporal lobes deal with memory, awareness and other sophisticated aspects of general consciousness. Dr Anthony Rudd, a geriatrician at St Thomas's Hospital, London, and spokesman for the Stroke Association, told BBC News Online: "Damage to this area could conceivably lead to changes in personality, loss of memory, lack of insight into one's surroundings.

"A CT scan will show how much structural damage to the brain there was, but it cannot show how much effect that will have on somebody. People with normal-looking scans can be severely demented."

The term progressive cerebral-vascular injury is simply a medical term for the effects of a stroke.

There are two types of stroke.

One is caused by a blockage in the blood supply to part of the brain.

This leads to the brain cells being fatally starved of oxygen and nutrients.

The second is caused by a rupture of a blood vessel in the brain, which leads to a blood clot forming in the tissue.

According to Dr Rudd, General Pinochet appears to have suffered a combination of both types of stroke.

He said: "It sounds as if there have been multiple events.

"If that is the case then over a period of time the chances of recovery are not good.

"Every individual is different, but it would be unusual to see somebody with that sort of damage making a dramatic recovery."

General Pinochet's medical report makes reference to damage to the pyramidal tracts.

These are the fibres that transmit messages from the cortex, or grey matter, of the brain to the spinal cord.

Effect of diabetes

The term diabetic neuropathy suggests that the general's long-standing diabetes has also caused damage to his body, specifically to the nerves that supply sensation to his arms and legs.

This could explain why the general is reported to have difficulty walking and standing up straight.

Another common symptom of long-term diabetes is the clogging up of the arteries, raising the chances of a stroke.

Dr Rudd said: "Clearly extensive bits of the brain have been affected by a poor blood supply, the arteries to the brain have been clogged up and various bits are getting damaged.