Study claims dyslexia slows drivers' reactions

Dyslexia could affect a driver's reaction as much as a moderate drinking session, a Norwegian scientist has claimed.

Hermundur Sigmundsson, from the University of Science and Technology in Norway, conducted a study comparing how quickly dyslexic and non-dyslexic drivers reacted to traffic signs.

The results, published in New Scientist, found that those with dyslexia took, on average, 30% longer to react.

Seventeen volunteers were used in the tests, six of whom were dyslexic. The volunteers had to drive along a simulated country road at between 50-80km per hour and then drive through a city at lower speeds for ten minutes. The reaction times to various traffic signs that were flashed up by the simulator were recorded and it was found that dyslexic drivers were 0.13 seconds slower to react during the rural drive and 0.19 seconds slower than the non-dyslexics in the city drive.

The results concur with other studies, which have suggested that dyslexia, which is characterised by reading and writing difficulties, may also affect the way the brain processes sensory information. Studies have shown that children suffering from dyslexia are often clumsy and take longer to learn to crawl, walk and ride a bicycle.

Dyslexia charities have criticised the study. Dr John Rack, from the Dyslexia Institute told the BBC that it was "an overgeneralisation and oversimplification of what dyslexia is".

However, Mr Sigmundsson admitted that his results needed to be confirmed by larger studies.

Drivers who are just over the UK's alcohol limit (which can be exceeded by drinking just two pints of beer) are normally 10% slower to react than they would if they had not been drinking. Oliver Carsten, an expert on driving impairment at the University of Leeds, said that dyslexic sufferers should not be banned from driving. He told New Scientist: "Rather than banning them, it would be better to warn them". He also said that drunk drivers also tended to be more likely to miss objects in their peripheral vision and may also drive more aggressively.

A spokeswoman for the Department of Transport also told New Scientist that having quick reactions did not necessarily make you a good driver. She said: "Reaction time is only one of the cognitive functions needed for driving, and it has not been consistently shown to be a good predictor of driving performance."

Mr Carsten agreed, adding: "Young drivers have shorter reaction times but they have more accidents because they are overconfident."

(KMcA/SP)