The “neuroprosthetic” technology involved installing a credit-card-sized electrode panel on the surface of a volunteer’s brain, then collecting electrical signals as the person — a man completely paralyzed by a brain-stem stroke 15 years ago — tried to form words.

Over a period of several months, scientists worked with the man to develop a catalog of 50 words that could be translated from his thoughts into hundreds of phrases and sentences, such as “I am thirsty” and “I need my glasses.” The translation produced up to 18 words a minute with 93% accuracy.

Results of the trial were published Wednesday in the New England Journal of Medicine.