SBS debunked

Q. Do you have an opinion about whether or not somebody could have
shaken a two-and-a-half year old child that weighed 33 pounds so violently that the child died the next day from shaking?

A. My opinion is that that couldn’t happen. Based on the literature that’s been published, my opinion is that is not how this child died.

– Dr Monson testifying at the PCR hearing (2018)

Alongside the evidence of seizures and explanation of bruises, Dr Riddick’s change of mind on little Bryan’s cause of death was due to developments in the science around Shaken Baby Syndrome that occurred after the trial.


Tasha’s conviction rested on the theory of Shaken Baby Syndrome (“SBS”), a hypothesis that since her trial has been repeatedly disproven and shown to be unsubstantiated.

SBS was first hypothesised by paediatric neurosurgeon Dr Guthkelch in the 1970s.  Guthkelch proposed that a triad of symptoms in a baby might be explained by shaking. 

The three elements of the ‘triad’ are: subdural haematoma, brain swelling, and retinal haemorrhage.

The theory allows no fluid interval between the shaking and the presentation of symptoms/collapse. Therefore, whichever adult last had the injured baby in their care is automatically held as the perpetrator of those injuries.

SBS rapidly became adopted as fact without any scientific proof.

Dr Norman Guthkelch

This unsubstantiated theory has, since its inception, led to the imprisonment of hundreds of innocent carers with some even sentenced to their death (See Sabrina Butler and Robert Roberson).

Guthkelch himself, shortly before his death, expressed horror at his unproven hypothesis being used to imprison innocent people:

“In a case of measles, if you get the diagnosis wrong, in seven days’ time it really doesn’t matter because it’s cleared up anyhow. If you get the diagnosis of fatal shaken baby syndrome wrong, potentially someone’s life will be terminated”

Dr Norman Guthkelch (2011)

Was little Bryan shaken?

Even if Guthkelch’s hypothesis of SBS is true, little Bryan’s death still resists shaking as the cause of death. This is for several reasons.

Firstly, little Bryan was two-and-a-half years old. Dr Riddick stated that the usual age of a child diagnosed with SBS is under one year old.

Q. What was the age of the decedent?

A. Two and a half years.

Q. And is that a usual age for an SBS diagnosis?

A. No.

– Dr Riddick testifying in the PCR hearing (2018)

Little Bryan on the 27th April 1997

Secondly, little Bryan did not have all three injuries included in the triad. Whilst he did have brain swelling, his subdural haematoma was very small (Dr Mack describes it as a trace) and he had no retinal haemorrhaging.

Thirdly, little Bryan was a large two-and-a-half-year-old weighing 33lbs on his hospital admission. Tasha had just given birth less than two weeks before little Bryan’s death when she had a caesarean section and had her tubes tied. This left her with stitches and the explicit instructions from her doctors to not lift anything heavy or else her stitches would open.

If she had lifted little Bryan and shaken him, they would have opened. However, none of Tasha’s stitches were found to have opened.

This information was not shared with the jury.

Additionally, the location of injuries in little Bryan’s brain also rejects a finding of shaking. If the SBS hypothesis were true, one would expect to find injuries across both sides of the brain. However, little Bryan’s brain only suffered injury on the right side, according to Dr Mack, a radiologist who examined little Bryan’s CT scans and testified in the 2018 PCR hearing.  

debunking sbs

Since the trial in 2000, multiple studies have been performed that show shaking an infant cannot cause the injuries in the triad thus debunking the theory.

Many of these studies have been in biomechanical engineering, where models of infants are subjected to various methods of shaking to see what head accelerations can be produced. To cause the injuries associated with SBS, these head accelerations must exceed what is known as the injury threshold.

Dr Monson, a biomechanical engineer, testified in the 2018 PCR hearing that recent studies showed that the head accelerations recorded in models of infants being shaken were well below the estimate injury threshold.

One study involved a team of football players at the University of Pennsylvania shaking models of infants. Their findings showed that they were unable to generate sufficient injury potential that exceeded dropping a baby on a foam rubber pillow.

An example of an infant model often used in studies

Biomechanical studies have also found that as the mass of the infant increases, the head accelerations measured during shaking decrease.

A. […] there was one study where a 10-pound dummy was shaken and a 24-pound dummy was shaken and the head accelerations of the 24-pound dummy were actually ten times lower than the head accelerations of the 10-pound dummy. So, in this case we’ve got a child that’s even larger than that. It’s just going to be very difficult to shake a child that size to produce significant head accelerations.

– Dr Monson testifying in the PCR hearing (2018)

At the time of the original trial in 2000, the above studies had not yet been conducted and scientific opposition to SBS was only just beginning to emerge. However, the developments that have since surfaced since the original trial have caused doctors all around the world to reject the theory.

Each year, new cases are being overturned as more studies come to light debunking SBS. The new developments in SBS science and Dr Riddick’s change of testimony were brought before a judge in 2018 in a post-conviction relief hearing. However, the judge held it did not qualify legally as new evidence and so Tasha was denied a new trial.

She still remains imprisoned today.