Brazilians create speech analysis method that identifies schizophrenia

10/04/2012 - 10h00

The way someone tells a story can reveal many things, including psychiatric disorders. Brazilian researchers have created a method that can identify patients with schizophrenia and mania using only speech.

The work was began to be developed in 2006 and, over time, involved a team of scientists from various specialties, led by a team from the Brain Institute of UFRN (Federal University of Rio Grande do Norte in Natal).

The researchers created a model that turns the speech of patients into graphics (graphs). And from this pattern, it is possible to identify patterns and correlations that are quite specific to these two psychoses.

In the experiment, the researchers studied 24 people, eight of them with a previous diagnosis of schizophrenia, eight of mania and eight without any diagnosed psychosis.

THE METHOD

The first step is an interview in which patients are asked to recount a dream. This account is recorded and transcribed. Then one applies software used in the study of area graphs that is already enshrined in psychiatry, which highlights the relevant points in the speech of the patients.

The program, besides indicating the connection points of the conversation, shows the main differences in the discourse of the volunteers.

The results are easy to interpret visually. The graphs of patients with mania are more dense, with many comings and goings in relation to the theme of the story. In general, the person "gets lost" more in the conversation, a hallmark of people with this disorder.

But the graphs of patients with schizophrenia are more rectilinear and follow a less chaotic sequential. The patients tend to talk less, to be more contained in the reporting of their experiences.

"A trained psychiatrist is able, in a long conversation in the office, to reach the same conclusions. These speech patterns have already been noticed. What we are creating now is a faster and more quantitative way to address the issue," explains Natalia Mota, of the Brain Institute, one of the authors of the study, published in "PLoS ONE".

Although the scientists have achieved a diagnostic success rate of about 93%, much higher than the roughly 67% of the scales commonly used by psychiatrists, Mota emphasizes that the method should complement the assessments currently used. "It does not replace the office experience."

The neuroscientist Siddhartha Reddy, who also participated in the study, sees great potential in the method.

"For now, we analyzed only the way things were said.
The semantic issue is not yet in this study. But we've already begun next step, which will put it all together. We are working to improve this tool," says the scientist.

Translated by DAVE WOLIN