Stimulating the auditory cortex improves speech perception

Stimulating a specific part of the auditory cortex immediately improved speech perception over background noise in an epilepsy patient, according to new research in JNeurosci.

To treat severe cases of epilepsy, surgeons implant electrodes into the patient's brain to pinpoint the area triggering the seizures. During one of these procedures, surgeons implanted electrodes near part of the auditory cortex called the planum temporale (PT) that seemed to improve speech perception when stimulated.

Researchers at Columbia University and The Feinstein Institutes for Medical Research put together a set of experiments to explore the exact properties of the region, which had been difficult to study non-invasively. They stimulated the patient's PT while playing sound clips of someone talking with extensive background noise—like a noisy party. The patient deciphered the spoken sentence and rated the clarity on a scale from 1 to 5.

Without stimulation, that patient could hear only a few of the words and rated the clips as low as 2. After stimulation, they understood most of the words and rated clips as 4 or 5. The patient described the experience as, "The voices get a lot clearer. I still hear the noise, but the voice gets a lot clearer, as if someone is saying it in my ear." Future research will verify the role of the PT in speech perception in other patients.