That is the report from Nature News. They note that:
The electrode is different to others used for brain–computer interfaces, most of which are fixed to the skull rather than within a specific part of the brain. This means that the electrodes can move around, making it difficult to record from the same neurons every time or to leave the electrode in place in for more than a few months at a time.
The electrode used by Guenther’s team is impregnated with neurotrophic factors, which encourage neurons to grow into and around the electrode, anchoring it in place and allowing it to be recorded from for a much longer time.
As more public goodwill is seen from the results of this research, more money will probably be poured into it. The use of neurotrophic factors is interesting, and success in this area would raise serious questions about whether it could be used on healthy people as well to augment their senses or even to provide additional ones.