Hands-free devices may lead to spike in driving errors

Talking on a hands-free device while behind the wheel can lead to a sharp increase in errors that could imperil other drivers on the road, according to a new study by Indian-origin researchers.
Researchers from the University of Alberta in Canada found that drivers who talk using a hands-free cellular device made significantly more driving errors such as crossing the centre line, speeding and changing lanes without signalling compared with just driving alone.
The jump in errors also corresponded with a spike in heart rate and brain activity, found the study by Yagesh Bhambhani, a professor in the Faculty of Rehabilitation Medicine, and his graduate student Mayank Rehani.

"It is commonplace knowledge, but for some reason it is not getting into the public conscience that the safest thing to do while driving is to focus on the road," said Rehani, who completed the research for his master's thesis in rehabilitation science at the U of A.
The researchers became interested in the topic in 2009 shortly after Alberta introduced legislation that banned the use of handheld cellphones while driving but not hands-free devices.
In this study, they used near infrared spectroscopy to study the brain activity of 26 participants who completed a driving course using the Virage VS500M driving simulator at the Glenrose Rehabilitation Hospital.

Near infrared spectroscopy is a non-invasive optical technique that allows researchers to examine real-time changes in brain activity in the left prefrontal lobe.

Participants were first tested in a control condition, using the simulator to drive in city street conditions using no telecommunications device.
They were tested again while talking on a hands-free device during two-minute conversations that avoided emotionally charged topics.
The research team found there was a significant increase in brain activity while talking on a hands-free device compared with the control condition.
A majority of participants showed a significant increase in oxyhemoglobin in the brain, with a simultaneous drop in deoxyhemoglobin-a sign of enhanced neuronal activation during hands-free telecommunication.

"The findings also indicated that blood flow to the brain is significantly increased during hands-free telecommunication in order to meet the oxygen demands of the neurons under the 'distracted' condition," said Bhambhani.
He added the results did not reveal a significant relationship between enhanced neuronal activation and the increase in the number of driving errors, most likely because the near infrared spectroscopy measurements were recorded from a single site, the prefrontal lobe.