Individuals with schizophrenia often experience visual perception problems, including contour integration impairment, or difficulty visualizing a whole line from its fragmented parts. This is part of a growing body of evidence suggesting schizophrenia may impair gestalt perception, or the ability to recognize that an object is more than the sum of its parts. New research from Albright College in Pennsylvania suggests that such perception problems may exist, to some degree, at the first episode of psychosis, and may worsen the more psychotic episodes a person experiences. Keith Feigenson, Ph.D., assistant professor of psychology, has co-authored a new study in the journal Schizophrenia Research examining whether contour integration impairment is trait or state-related in schizophrenia. A trait characteristic is one that does not vary if a person has the disorder, and may include cognitive difficulties that persist even when a person is not experiencing psychosis. Conversely, state characteristics may vary with psychotic episodes. Hallucinations and delusions, for instance, are often state-related as they can disappear when people are feeling better, are taking medication, or are not experiencing psychosis. Based on their research, Feigenson and his colleagues determined that perceptual deficits seem to be trait markers, or are consistently expressed regardless of whether a person is in hospital or in recovery.
To determine this, researchers administered contour integration tests to three groups: individuals with chronic schizophrenia, individuals hospitalized for a first episode of psychosis, and a healthy control group. Test subjects were shown images comprised of small lines organized in a linear path. The lines formed an egg-shaped object embedded in the image, and were surrounded by other distractor lines. Researchers asked the subjects whether the egg shape pointed to the left or to the right, and increased the difficulty of the task by varying the angle of rotation of the lines. The tests were administered twice over an approximately two-week time frame – once when patients (both first episode and individuals with chronic schizophrenia) were admitted for short-term psychiatric hospitalization, and again at their discharge. The control group scored the best on these tests; the chronic schizophrenia group performed the worst; and the first episode group fell in the middle (although the performance of this last group was not statistically different from either of the others). Researchers found that, between the rounds of tests, contour integration ability actually improved to the same degree for all three groups. This was attributed to the fact that people generally improve with practice, and was not a result of the short-term impatient treatment.
The findings suggest that contour integration impairment is trait-related or a symptom of schizophrenia. However, not all people with schizophrenia experience contour integration impairment. Likewise, not all individuals with contour integration impairment are, or will, develop schizophrenia. In theory, said Feigenson, the appearance of contour integration impairment may be useful in predicting the future development of the disorder in at-risk individuals or helping to characterize people with ambiguous diagnoses. “But it would be important to rule out other causes, including vision problems,” he said. Researchers expect to administer follow-up tests on their subjects in the future.
This article first appeared Newswise, 26 January 2015.