READING MINDS.(brain-computer interface research)

One Friday morning last July, Niels Birbaumer, a neuroscientist from the University of Tubingen, in southern Germany, was driven from his hotel in the center of Lima, Peru, to a house protected by a half-dozen armed guards in a gated suburban enclave. He was accompanied by two colleagues--Herta Flor, a professor of neuropsychology, who is his girlfriend, and Thilo Hinterberger, a physicist and computer programmer--and by Jose Luis Palomino, who runs a company in Lima that distributes communication devices for disabled people. With the assurance of a regular visitor to the house, Palomino led the group through a split-level main room, filled with zebra-skin cushions and potted orchids, to a den decorated with sporting trophies, a stuffed deer's head, and a two-foot bottle of Teacher's whiskey. Sliding smoked-glass doors opened onto an L-shaped swimming pool in a bright, spongy lawn. A game of tennis could be heard from the other side of a tall hedge.

Palomino had set up a makeshift laboratory in one corner of the room. Two desks were placed at right angles: a large television monitor was set up on one, and on the other a computer was connected to a small amplifier. The three visitors from Germany plugged in their own laptop computer, and ran tests on the equipment, while politely accepting snacks brought by shy, silent maids. Esteban Ripamonti Aguad, nicknamed Polo, a jumpy, slightly unkempt man of twenty-five, who is the nephew of the owner of the house, came into the room. "We're very happy to have you here," he told Birbaumer, in Spanish. "We've been counting the days." He spoke quickly, underlining his words with whistles and darting hand movements.

Sometime after midday, there was a whisper--"Mr. Elias is coming!"--and through the glass doors one could see a wheelchair being guided very slowly down a ramp by three nurses and a doctor. Polo's uncle, Elias Musiris Chahin--the wealthy owner of a casino and two fabric factories--sat motionless in the chair. He had a scarf over his mouth, another over his head, and blankets covering his body. He was wearing wraparound dark glasses. On his feet were oversized slippers designed to look like leopard's paws, finished with cloth claws.

Once Musiris's procession reached the room, a nurse took off his glasses and scarves, and the extent of his paralysis became apparent. He was breathing with a respirator. His left eye was open only because the eyelid was held in place artificially, and the eyeball was stationary. His mouth, which he cannot move, was open very wide, as if at the midpoint of a yawn. Now and then, a nurse delicately used a damp cotton pad to push her patient's lower eyelid upward, to approximate a blink, and cleared saliva from his mouth with a small suction tube.

To use the blunt medical term, Musiris is "locked in": he is unable to communicate with the world, although it is assumed that his senses and his intellect are intact. In 1996, when he was fifty-three years old, Musiris received a diagnosis of a form of amyotrophic lateral sclerosis (A.L.S., or Lou Gehrig's disease), which is incurable. Last winter, he completely lost deliberate movement in his eyes, and, with it, the ability to indicate "yes" and "no." His thoughts became unknowable. Nobody fully locked in has ever answered a question.

Musiris's wife, Estrella, joined her husband. She is a tall, broad-shouldered woman in her mid-fifties, with a face dominated by dark-red lips. She made sweeping gestures of welcome, and gave everyone kisses, but she appeared weary in the role of expansive glamour. As Birbaumer later learned, she has been at odds with Musiris's two adult sons from his first marriage, largely over management of his businesses. It was also reported in the Peruvian press that she had argued with her sister-in-law over the origins of Musiris's condition--Estrella charged the sister-in-law with witchcraft, and was in turn accused of poisoning her husband with chemicals used to cultivate orchids. Meanwhile, Ripamonti, who is her nephew, has embraced the role of dutiful son. A few years ago, he moved in and took charge of Musiris's care. Depending on whom you ask, he either filled a vacuum that the dispute with Musiris's sons had created or executed a coup d'etat. Last year, he started saying that he could communicate with his uncle by reading how his pulse rate changed. He took questions from Musiris's family and business associates, and returned with answers after some hours in private with his uncle. (In the opinion of Birbaumer, who was never allowed to witness the process, the technique was "impossible"--Musiris was on artificial respiration, so he would not have sufficient control of his heart rate--and Ripamonti was guilty of wishful thinking, at best.)

Birbaumer knows that good science can happen in makeshift settings--it can flex in response to place or the impact of a new experimental thought--but for a moment he looked bemused by his surroundings, and by the size of the crowd now growing in the poolside room. He went over to Musiris, and, in a gentle alternative to a handshake, touched the back of his pale hand with three fingers, and spoke to him quietly in English and in broken Spanish. Musiris was then placed at a point about six feet in front of the TV screen. Birbaumer measured his head, and marked positions on his scalp with a red felt-tip pen. He glued electrodes to the spots, and connected them to the amplifier. "Don't try too hard," he said encouragingly to Musiris, who had been introduced to the equipment in the weeks before Birbaumer's arrival. He added, "Vamos."