  Brain Computer Interface (BCI) helps in processing and extraction of useful
information from the acquired brain signals having applications in diverse
fields such as military, medicine, neuroscience, and rehabilitation. BCI has
been used to support paralytic patients having speech impediments with severe
disabilities. To help paralytic patients communicate with ease, BCI based
systems convert silent speech (thoughts) to text. However, these systems have
an inconvenient graphical user interface, high latency, limited typing speed,
and low accuracy rate. Apart from these limitations, the existing systems do
not incorporate the inevitable factor of a patient's emotional states and
sentiment analysis. The proposed system EmoWrite implements a dynamic keyboard
with contextualized appearance of characters reducing the traversal time and
improving the utilization of the screen space. The proposed system has been
evaluated and compared with the existing systems for accuracy, convenience,
sentimental analysis, and typing speed. This system results in 6.58 Words Per
Minute (WPM) and 31.92 Characters Per Minute (CPM) with an accuracy of 90.36
percent. EmoWrite also gives remarkable results when it comes to the
integration of emotional states. Its Information Transfer Rate (ITR) is also
high as compared to other systems i.e., 87.55 bits per min with commands and
72.52 bits per min for letters. Furthermore, it provides easy to use interface
with a latency of 2.685 sec.
