Limits

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As exciting as this technology seems, there are still quite a few important limits.

Training

The fact that each user has to go through training sessions to record brain waves and match them to particular commands is expected but a barrier to adoption for most people. Unless an application solves a real need and the accuracy of the device is really good, I cannot imagine people spending time training a brain sensor.

Latency

When building my prototype using mental commands, I realised that there was a bit of a delay between the moment I started thinking about a particular thought and the moment I could see the feedback in my program.

I assume this is because the machine learning algorithm used in the background receives data from the device in real time and needs samples for a certain amount of time before being able to classify the current thought based on the thoughts previously trained.

This does impact the type of application you can build with the sensor. For example, building a meditation app would be ok as the latency would not have a major impact on the user experience, however, if you want to build a thought-controlled wheelchair, you can imagine how latency could have a very important impact.

Invasive vs non-invasive

EEG devices are great because you don’t need any surgery; you just put the headset on, add some gel on the sensors and you’re ready to go! However, the fact that it is non-invasive means that sensors have to track electrical signals through the skull, which makes this method less efficient.

The temporal resolution is really good as the sampling rate is pretty fast but the spacial resolution is not great. EEG devices can only track brain activity around the surface of the scalp, so activity happening a bit deeper in the brain is not tracked.

Social acceptance

Wearing a brain sensor is not the most glamorous thing. As long as the devices look the way they do, I don’t think they will be adopted by consumers. As the technology improves, we might be able to build devices that can be hidden in accessories like hats, but there is still another issue, brain sensors can get uncomfortable after a few minutes.

As an EEG device is non-invasive, the sensors have to apply a bit of pressure on the scalp to track electrical signals better. As you can imagine, this slight pressure is ok at first, but slowly becomes uncomfortable over time. Moreover, if a device needs some gel applied on all sensors, this is an additional barrier for people to use it.

Even if the current state of EEG sensors does not make them available or appealing to most people, there are still some interesting possibilities for the future.