Mind over immobility

A group of scientists from Kandy are working on an affordable device to make the disabled live independent lives

by Pradeep Priyathilaka

Thousands of people in the world are suffering from severe motor impairments due to debilitating diseases, accidents and injuries. They cannot walk, move their hands or speak with others; they just live in a bed or a wheel chair. Can modern science provide relief to them?

For many years, several research laboratories around the world and various research groups in Asia, Europe and USA have been working on systems, which allow a direct dialogue between man and machine. These systems are usually built based on two techniques, which depend on the severity of the impairment.

One is a system, that enables the mind to control outside machines with thoughts known as the 'Brain Computer Interface' or BCI, which is literally a direct technological interface between a brain and a computer that does not require any physical movement from the user. The other method is communication through muscle movements (CMM), which uses electric signals generating from muscles located in any part of the body.

This means people with severe physical disabilities such as extreme motor impairment (late stage Amyotrophic Lateral Sclerosis (ALS), severe cerebral palsy, head trauma and spinal injuries can control equipment such as wheelchairs and TVs, and are able to communicate with computer voice in his or her native language (in Sinhala, Tamil or English) by using their thoughts, muscle movements or eye movements. In these two methods, neural impulses generated in the brain, eye or other muscles in the body are intercepted and utilised to control electronic devices such as a computer, TV, or a Radio.

A group of Sri Lankan scientist led by Professor Asiri Nanayakkara, working at the National Institute of Fundamental studies, Kandy, has developed a local BCI system based on Electroencephalogram (EEG), which detects the brain activities due to changes in thoughts and a CMM system using Electromyography (EMG), which detects the electrical potential generated by muscle.

Low cost software

Imported BCI and CMM systems are quite expensive for most of the people in Sri Lanka and they are needed to be custom - build according to the medical condition of the patient. This means large number of Sri Lankans cannot afford to own a BCI or CMM system equipment. One of the aims of the investigations of Professor Nanayakkara and his research team has been to design and develop a low cost software and hardware needed for BCI and CMM systems. Another aim was to develop a real time BCI system, which could be used by severely physically disabled people in Sri Lanka.

Both BCI and CMM systems consist of two components; hardware and software. With the hardware, EEG/ EMG signals generating from thoughts of the brain or muscle movements of the body are amplified and then digitised. The digitised EEG/ EMG signals are then analysed by a computer, which then takes action according to the outcome of the analysis -move wheel chair, on or off TV, lights and much more- using pre-programmed instructions.

EMG signals are in millivolts, while EEG signal are very weak and measured in microvolts. As a result, EMG signals are less likely to get contaminated by noise generated by outside sources. Therefore, it is always favourable to use CMM system wherever possible.

The degree of disability of the patient determines the method (BCI or CMM), which is most suitable for him/her. If a patient can at least control a single muscle, CMM is the best choice for communication.

One of the most popular mental tasks used for BCI systems is imaginary motor movements (the patient is imagining that he/she is moving part of his/her body). Not every thought of the brain can alter the EEG signal. As a result, the number of thoughts which can make a detectable change in EEG is very limited.

Imaginary arrow movements

Professor Nanayakkara and his research group have been focusing on finding new mental tasks, which can be used with their BCI system effectively. And team has succeeded in finding a new set of mental tasks, names imaginary arrow movements, which can be performed naturally and identified by a BCI system accurately.

The performance of this new set of mental tasks has been tested and found to be quite accurate and can be used to move the cursor on a computer screen effectively.

As the first objective, the low cost 8 channel EEG/EOG (Electrooculogram) amplifier, which had been constructed earlier in NIFS laboratory was modified to be used with a real time BCI system. Amplification Unit Filter Further a complete software package for recording EEG, EMG and EOG (Electrooculography - a technique for measuring signals due to eye movements) signals receiving from this amplifier was developed by his research team. Further, an EEG based BCI software system (named GENIE) was constructed to accept and classify signals from patients in real time.

Since over 90% of the severely paralysed patients could make eye movements, additional facilities have been incorporated into the BCI system to accept commands through EOG due to slight eye movements. A new hardware (remote control) system was developed in order to control televisions, lighting and other equipment from the computer. This system can be used to control televisions, adjust room lighting, and communicate with Sinhala computer speech.

The research team successfully demonstrated the BCI system using Electroencephalogram (EEG), which detects the electrical potential generated by thoughts, in front of a live audience at NIFS premises.

The research team is currently developing a portable, low energy-consuming electronic BCI system, which uses a wireless link between the brain and the computer. It is more comfortable than conventional BCI systems due to the absence of wires, and provides the ability for patient to move freely. They have scheduled to finish it by the end of 2016.

The final aim of Professor Nanayakkara and his research team is to successfully finish the portable BCI and CMM systems, which can be used by patients with many types of physical disabilities to live actively while interacting with outside world without being heavily dependent on their love ones. There will be new hope to people with disabilities to overcome some of the problems that they face in day to day life. BCI and CMM systems which were successfully developed first time in Sri Lanka can also be used in mobile phones, computer games and also in developing new electric equipment in the near future.

(This article was compiled after discussing with the team leader of the Artificial Intelligence and Applied Electronic research unit of National Institute of Fundamental Studies, Professor. Asiri Nanayakkara. . The writer is a Communication & Media Officer, Science Education & Dissemination Unit, National Institute of Fundamental Studies, Kandy)