Researchers have developed a series of new eye tests in order to differentiate between individuals with schizophrenia and those without it, according to a recent study published in Biological Psychiatry.
A 2007 study by a Binghamton University researcher reported similar methods of analyzing eye movement as a way to determine if a person is schizophrenic.
The experts came up with a model, which was 98.3% accurate, to distinguish all cases of schizophrenia from healthy control participants.
Lead authors of the study, Dr. Philip Benson and Dr. David St. Clair said that their discoveries were outstanding. They explained:
“It has been known for over a hundred years that individuals with psychotic illnesses have a variety of eye movement abnormalities, but until our study, using a novel battery of tests, no one thought the abnormalities were sensitive enough to be used as potential clinical diagnostic biomarkers.”
The series of tests included gaze fixation tasks, free-viewing, and smooth pursuit. People with schizophrenia have established deficits in their ability to follow slow-moving objects steadly with their eyes. The eye movement does not match the trajectory of the moving object; it slows down behind it, but then catches-up using a saccade (a rapid eye movement).
During the free-viewing test, a picture was shown to the participants. Those with schizophrenia displayed abnormal viewing patterns compared to those without the condition.
In the fixation test, the individuals were asked to keep a fixed stare on one steady object, something that is often hard for people suffering from schizophrenia.
As the researchers anticipated, when evaluating the eye tests, people with schizophrenia showed abnormal behavior compared with those without schizophrenia.
After determining this, the experts utilized many techniques to model the outcome. Accuracy of the algorithms was determined using data from the eye tests of a different group of individuals. One of the models was 98.3% accurate, when all data was combined.
Dr. John Krystal, Editor of Biological Psychiatry, commented: “It is encouraging to see the high sensitivity of this model for the diagnosis of schizophrenia. It will be interesting to see the extent to which this approach enables clinical investigators to distinguish people with schizophrenia from individuals with other psychiatric disorders.”
Benson and St. Claire concluded:
“We now have exciting unpublished data showing that patterns of eye movement abnormalities are specific to different psychiatric subgroups, another key requirement for diagnostic biomarkers. The next thing we wan to know is when the abnormalities are first detectable and can they be used as disease markers for early intervention studies in major mental illness? We are also keen to explore how best our findings can be developed for use in routine clinical practice.”
Written by Christine Kearney