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Caveat against brain injury

Helmets may not be fool proof but can minimise risks of injury

With the proposed new law of compulsory helmet wearing coming into force from next month, the raging debate these days is on the safety of this head gear.

Globally it is accepted that wearing helmet saves the brain tissue. It is estimated that nearly 63 per cent of all two wheeler accidents result in head injury. Helmet is a good weapon to prevent skull fracture and brain injury.

No significant progress has so far been made in the management of brain injury. A brain cell once damaged due to any cause is permanently damaged. A study by NIMHANS, Bangalore and WHO, revealed that 40,000 people died in road accidents in 1986 which doubled in 2001. About 66 per cent of these deaths were in the age group 16-44 years.

Tamil Nadu was among top 10 States for deaths caused in road accidents. A whopping 93,000 people died and 4,65,000 people got injured in road accidents in 2004.

The Asian Development Bank states road accidents cost developing countries one to three per cent of GNP annually. Chennai Traffic Police recorded 1,136 fatal accidents in 2006 of which 50 per cent were two-wheeler accidents. And importantly, only two people died with helmet on which underlines the necessity of wearing it.

But it does not mean helmet is accident and injury proof. The nature and quantum of injury to the brain is decided by the velocity and impact at that moment. Basic idea of wearing helmet is to prevent traumatic skull and brain injury.

The common type of injury in road accidents is a closed head injury meaning where the skull is intact. It results in violent acceleration of head, which causes the brain to move around inside the skull. There is the risk of tissues and blood vessels tearing and causing internal bleeding.

Modern helmets are constructed from plastics often

reinforced with Kevlar or Carbon fiber. They generally have fabric and foam interiors for both comfort and protection.

Helmets have two principle protective components - A thin hard outer shell, typically made from ABS plastics, fiber glass or Kevlar which absorbs energy in an impact. It distributes local forces from an impact and allows sliding on road surfaces. It protects the face and temporal bone and prevents penetration by any pointed objects

A soft thick inner liner is usually made of expanded polystyrene or polypropylene foam. Provision of this material in the inner liner prevents disintegration upon abrasive contact with pavements. It is important that the liner is soft, stiff and thick so that the head decelerates at a gentle rate as it sinks into it.

Helmets themselves can be rarely dangerous. A cheap helmet without ISI standard, its base reaching the nape of the neck, can cause acute flexion cervical injury.

Pillion riders too should wear helmet as they are at a higher risk than the driver with nothing to hold on to.

Standard helmets are manufactured according to certain norms. It has a mild gauge steel globe or high quality rigid plastic, which does not buckle under trivial pressures or impact. There should at least be a two inch thick thermocol lining between the two shells of a helmet which absorbs and protects from heat. The helmet should have a proper double buckled clip to strap it. Helmets with straps which don’t have a proper locking system, can easily fly off heads during force of an accident. Hence, they should be avoided.

It should have ISI: No. 4151, and certification without any forged seal on it. Always buy from a standard dealer, who stands responsible for that product

The helmet should fit like a cap on the head. One should be able to remove it easily without any pressure on the head. After wearing the helmet for a few minutes, remove it and look for pressure points on your forehead, temples, chin and back of the head. Never buy a helmet with compression as it irritates the skin, causes redness and ulceration. Go for bright colours to improve visibility during night. Preferably have a sticker for front glow.

Do look for the polystyrene foam in the deep surface of the helmet as it absorbs sweat from the head. Buy one which has a chin guard too.

Visor should not be refractile. Wear the helmet and see if the light is clear without any blurring. There should not be any distortions as a wrong visor can result in double vision.

Even if you have to travel a short distance, wear the helmet. Wearing helmet may be cumbersome initially but you will get used to it soon.

DR. NAGARAJAN VENKATARAMAN,

(Senior Neuro Physician , Madurai)

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