Brain-Computer Interaction is an augmentative technology meaning that it is used to enhance or augment the capabilities of a human being. In the context of health care, it is especially used for those people who are paralyzed and cannot use their motor mechanism or effective organs such as hand and leg movement. Such persons have severe motor disabilities and lose their control of peripheral muscles and nerves. This technology empowers users with communication and control channels that do not depend on the brain’s normal output channels of peripheral nerves and muscles. The working of BCI is governed by capturing the intent of a person, translating intent into actions, and performing the intended action. For this purpose, a BCI system has three main components which are also shown in the figure.
Input: The objective of this function is to capture the intent of performing an action for example moving the right arm in an upward direction, or moving a cursor etc. Such intents are reflected in the brain as neuronal activity. A device called electroencephalography (EEG) mounted on the surface of head captures is used to capture these neuronal activities. These neuronal activities are electric signals are characterized through electric potential and frequency.
Transnational Algorithm The acquired signals are processed by a signal processing algorithm to extract the relevant features such as electric potential associated with a particular electrode of EEG. The transnational algorithm establishes a correlation between extracted features and actions to perform. These translation algorithms may be simple linear or non-linear equation to the complex artificial neural network.
Output: The objective of this function is to initiate the intended action such as moving the left arm. The output issues command to motor devices that are now controlled by the BCI system.
In addition to EEG, other signal acquisition methods such as electromyographic (EMG) and invasive techniques of immersing electrodes inside the body are also used.
The BCI is an evolving technology. To coordinate BCI based technology development, a standard system called BCI2000 has been specified to validate and evaluate the output of a BCI system.