- By Thin Hlaing Hmwe (Junior)
Mobile phones have become indispensable as communication tools in the present world. During recent years, worldwide mobile subscriptions has grown more and more for every operators. In Myanmar, there has also been increased numbers of mobile phone users reaching the bottom of the economic pyramid to cater up to the lowest socioeconomic levels.
Widespread mobile phone ownership and usage has aroused public concern over possible harmful biological effects of their use. There are electromagnetic frequencies of mobile phones emitting radiations between the 800 MHz and 2000 MHz. These causes excitation and rotation of water molecules and some other organic molecules. Therefore, they cause thermal and non-thermal effects on human beings. The effects of electromagnetic fields (EMF) transmitted by mobile phones over human health is a matter of public and scientific concern.
Burning sensation and sensation of warmth around the ear, headache, sleep disturbance, changes in the cognitive functions and neural activity as well as changes such as decrease in the cerebral blood flow and alternation in functioning of blood in brain as barrier are the reported effects of mobile phones use. The potential carcinogenic effects of radiations emitted from mobile phones is controversial. Therefore, any biological effect related to mobile phone use should be considered as a high-priority health issue.
Our hearing system is in the close proximity to the mobile phone. So, hearing system is potentially the most affected target for thermal and non-thermal effects. The external ear provides the route by which electromagnetic frequencies from mobile phones reach the peripheral and central auditory system. The system leads to relatively high energy deposition in the ear. The auditory system and particularly the cochlea outer hair cells are known to be highly sensitive to a variety of exogenous and endogenous factors. Externally applied electrical and magnetic fields are known to produce some hearing sensation in the ear. The proximity of ear to electromagnetic source may lead to even larger damage and side effects such as hearing loss. A report released from a research in India revealed that people who talk on a cell phone for more than an hour a day were found to have suffer losses of high frequency hearing.
Little attention has been paid to the effects of electromagnetic field of mobile phones on hearing by many users. Till this date, the interaction between electromagnetic fields emitted by mobile phones and auditory function is not well established . However, every users should be aware of it.
There are two common technologies used by mobile phone networks for transmitting information. They are TDMA i.e. Time Division Multiple Access and CDMA i.e. Code Division Multiple Access.
TDMA also known as GSM i.e. Global System for Mobile communications does it by chopping the signals into sequential time frames. Each user of the channel takes turns to transmit the receive signals. In reality, only one person is using the channel at a given point of time. One of the important features of GSM system is the Subscriber Identity Module (SIM card). The SIM is a small, detachable smart card, which contains the user’s subscription information and phone book. This allows the user to retain his or her information while switching mobile phone handsets. Alternatively, the user can also change service provider while retaining the handset, by changing the SIM card. GSM is currently the market leader in mobile phone industry.
CDMA is based on spread spectrum technology which uses the whole bandwidth available. This allows each user to transmit frequency to the entire spectrum at all the time. CDMA uses a type of digital modulation called spread spectrum. CDMA spreads the voice data over the channel in a random fashion.
The receiver undoes this randomization and collects the bits together to produce the sound. CDMA is an example of multiple accessed, in which several transmitters can send information over a single communication channel at the same time. This allows several users to share a band of frequencies.
It should be noted for every user that GSM phones emit continuous wave pulses, so there is a great need to reduce the exposures of electromagnetic fields emitted from the cell phones with ‘continuous wave pulses’. On the other hand CDMA phones do not produce these pulses. GSM phones emits about 28 times more radiation when compared to the CDMA mobile phones. Therefore, GSM phones are more biologically harmful as compared to CDMA.
The subtle deleterious effects to hearing can be assessed by modalities such as brainstem evoked audiometry response (BEAR), otoacoustic emission (OAE) and pure tone audiometry etc. They measure the cochlea and out hair cochlea cells and middle ear function respectively. But these terminologies are very complex for an ordinary user to understand easily. Therefore, one had better to be aware of that every mobile phone can give the users both advantages and disadvantages. It is essential for every user to use the mobile phones wisely and beneficially with little hazard. It is also necessary to know almost thoroughly about the devices with which you are going to use.