KUALA TERENGGANU: Somnolence, or drowziness which causes someone to unknowingly slip in and out of sleep, could be the culprit behind scores of horrific highway accidents.
But fatigue, insufficient rest, or lack of sleep, may not be its root cause.
Rather, certain disorders related to excessive daytime sleepiness and shift-work could be the reason for somnolence during long-distance driving, points out leading medical practioner, Lt Col (Rtd) Dr Meer Ahmad Mydin Meera.
A specialist in aerospace medicine, occupational safety and health, Dr Meer – a senior public health consultant with Meer Ahmad Healthcare Consultancy in Shah Alam, Selangor – is convinced that somnolence is responsible for numerous traffic mishaps, especially on the lengthy North-South Expressway and East Coast Highway.
He does not discount human carelessness and poorly-maintained vehicles as factors in many crashes – such as the recent Tanjung Malim tragedy which saw a trailer lorry’s inferior-quality, retreaded tyre burst at high speed.
Dr Meer cited a Malaysian Institute of Road Safety Research (Miros) survey which revealed that 114,151 people were killed in traffic accidents from 1997 to 2014, which averages out to 6,341 fatalities annually, over the 18-year period.
The Transport Ministry, meanwhile, said Malaysia records 2.55 deaths for every 10,000 registered vehicles in 2015 – a figure higher than in developed countries like the United Kingdom, Sweden and Australia, which had less than two deaths in the same period.
“Somnolence as the cause of road traffic accidents needs to be revisited, mainly because fatigue is not the sole cause of somnolence.
“And it may not even be the most important cause. Somnolence on the road may be due to circadian-rhythm (biological clock) disorders and diseases such as diabetes, sleep apnea, insomnia and narcolepsy (a nerve system disorder-related uncontrollable sleep condition).
“Even drivers who are well-rested and had a good night's sleep can experience uncontrollable somnolence, leading to lethargy, weakness and lack of mental agility, resulting in dozing while driving,” he said.
Dr Meer said other factors that contribute to somnolence include one’s physical health, infection, illness, injury, mood disorder (depression, anxiety or stress) and medication.
“There are several diagnostic tests available, including the Epworth Sleepiness Scale, which can be used to ascertain the seriousness and likely causes of somnolence.
“As somnolence is a symptom, the treatment will depend on its cause, and steps taken to avoid it,” he said.
Recently, Dr Meer conducted a survey in the ‘Doctors Only Bulletin Board System’ Facebook group, which comprises 12,000 members.
“I asked members whether they experienced somnolence while driving, especially in the early mornings, after meals and during long-distance driving, even after having rested adequately, or a good night's sleep.
“Thirty members responded, out of which 13 replied that they experience it ‘at least once a week’! Only six replied that they never experienced it.
“Those who experienced it are aged 30 to 60, with an equal balance in males and females,” he said.
To avoid somnolence while driving, Dr Meer suggests that anyone applying for a driving licence undergo a thorough medical test, with periodical tests undergone for licence renewals.