It takes extreme force to inflict shaken baby syndrome on a infant, an American expert on the condition said this week in an effort to dispel myths that it can occur from short falls or bouncing a baby.

Dr. Randell Alexander, the shaken baby syndrome (SBS) expert who testified at the trial of Karim Salahuddin ? convicted of murder on Wednesday for inflicting SBS on his baby daughter ? has been studying SBS for over two decades.

He told The Royal Gazette he has testified in cases related to SBS roughly twice a month since he began specialising in this area of medicine some 20 years ago.

Also a professor of paediatrics at the University of Florida, Dr. Alexander said there are between 1,200 and 1,600 cases of SBS every year in the United States.

SBS occurs when a baby is shaken back and forth in a violent motion, he said and you can not give a child SBS by simply bouncing it around.

On the ZBM news on Wednesday night, Dr. Alexander demonstrated how SBS occurs using a doll ? he gripped the doll around the shoulders and shook the baby back and forth violently.

The neck of the doll snapped back and forth very rapidly.

?What happens is that there is significant bleeding and brain injury around the brain with bleeding in the eyeballs or what we refer to as retinal haemorrhages,? said Dr. Alexander.

?The brain is yanked back and forth which stretches the brain cells. There are hundreds and billions of cells which pull on each other inside the brain, doing damage to the inside of the cell. The cell ends up broken and non-functional.?

Out of all children who are shaken, 25 percent die but a significant portion, 75 percent survive, although these children struggle with speech and mental impairment and sometimes blindness and low IQ.

SBS was first diagnosed back in the 1860s by British neurosurgeons, he said.

It is also studied in the UK by a number of experts, most notably Robert Mimms, a Paediatric Neurologist in Scotland.

Dr. Alexander has also studied the reasons behind SBS-inducing behaviour.

The main reason he has identified for people taking this highly destruction action against children is frustration.

Parents, an others, become extremely frustrated when their child just won?t stop crying.

?This often happens when children keep on crying at a time when parents are not capable of dealing with the crying,? he said. ?We would find such a situation annoying, but they are determined to get the child to stop crying. It puts them in a rage. Later, they usually say ?this is a bad idea?.?

He said a common line of defence in such cases is that a parent or care giver will claim either they don?t know how the injuries happened or the child fell off a sofa or bed.

But the time frame also helps physicians to diagnose SBS as the brain injuries usually have immediate symptoms.

Dr Alexander said humans, particularly children, often fall and have small accidents throughout their childhood but our bodies are built, through evolution, to handle minor injuries.

?Parents have considerable experience with short falls,? he said. ?Often the child suffers minor injuries. These are falls children can take.?

SBS is becoming better understood, he said, and being spotted more often.

Dr. Alexander said in the US medical students are taught to understand and diagnose the symptoms of SBS and child abuse paediatricians specialise in its symptoms.

In order to avoid becoming frustrated if your child is crying, Dr. Alexander recommends going to another room and taking a short break or calling a family member or friend for help. Crying is not necessarily a signal of distress in children, he said.

?The good thing is that after four months crying doesn?t usually last too long,? Dr. Alexander said.

Information about SBS can be found on the website www.dontshake.com.