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Groton Maze Learning Test Found To Be Accurate Indicator For Executive Function In Schizophrenia Patients

February 24, 2014

Judith Jaeger

Judith Jaeger

One of the brain’s most important roles is coordinating our daily life through an ongoing series of activities including decision making, planning, reasoning and problem solving. This collection of tasks, known as executive function, is called on when a new situation requires a novel response. It is often this set of cognitive abilities that breaks down for schizophrenia patients, resulting in disorganized thinking and disruption to their daily lives. For physicians and medical researchers, being able to test and assess this impairment in patients is difficult as there is no single task to isolate.

Last week, at the 10th Annual Scientific Meeting of the ISCTM in Washington D.C., Cogstate scientists presented the results of a new study showing that a computerized test, called the Groton Maze Learning Test, is able to capture subtle changes to cognitive executive function that match a patient’s performance on an established test for everyday living.

As an example of executive function, consider your brain’s role when driving a car. When you’re out on an open highway, most of your cognitive actions come from automatic, learned schemas which don’t require much conscious thought. But once you drive into the city and have a specific destination in mind, juggling the multiple tasks of navigating traffic, planning your route and reacting to unexpected events requires your brain’s “executive system” to focus your attention, follow rules and make decisions.

Executive dysfunction is a common challenge faced by schizophrenia patients. Understanding the cause and possible treatments for these symptoms requires a way to standardize and measure changes in their condition. Unlike a specific disability where we can easily measure improvement, like being able to read, executive function requires a unique test that calls on working memory and planning in a goal-directed environment.

“Impairments in executive function are a hallmark of schizophrenia and at least in part underlie the disability that is so common in this disorder,” said Judith Jaeger Ph.D., VP of clinical trials at Cogstate and professor of psychiatry and behavioral sciences at Albert Einstein College of Medicine. “But executive dysfunction can be difficult to measure, and most executive function tests aren’t accurate if you give them repeatedly because they typically require you to figure out the rules of how a test works. Once you’ve figured out the rules, the test is “spoiled”. That makes it difficult to test improvement in executive function from a cognitively enhancing drug, where repeated testing before and after taking the drug is a requirement.”

The Groton Maze Learning Test (GMLT), developed several years ago in a collaboration between Cogstate and Pfizer scientists, is a unique executive function test that asks users to discover a hidden maze in a matrix of boxes. The advantage of the GMLT is that it can be repeated often because instead of having to figure out the rules, it requires the subject to apply a set of rules that they are given. This prevents the user from eventually outsmarting the test through repeated attempts, known as “practice effects.”

To be sure that the GMLT measurement relates to the real world living problems of patients, Dr. Jaeger, along with Dr. Paul Maruff and Joel Fichera, tested 64 schizophrenia patients and 38 healthy volunteers. The GMLT was administered to both groups, along with a test for functional activities of daily living as measured by the UCSD Performance Based Skills Assessment (UPSA-2).

Developed at the University of California – San Diego in 2001, the UPSA-2 measures basic everyday living skills in older people with schizophrenia. The UPSA-2 consists of five subtests assessing the individual’s ability in the following domains: Planning/Organization (i.e. planning a grocery shopping trip), Finances (i.e. counting money or writing a check), Communication (i.e., calling a doctor for an appointment), Travel (i.e. following directions to the store), and Household (i.e. making a meal).

The Cogstate scientists found a direct correlation between performance on the GMLT and on the UPSA-2. Those patients that scored poorly on the Groton Maze also underperformed on the daily living tests.

“These findings show that the GMLT correlates with functional activities of daily living to a degree that is similar to other cognitive tests,” said Jaeger. “These findings confirm that in patients with schizophrenia, the GMLT captures the critical executive dysfunction that is also associated with their disability. It performed about as well as other executive functioning tests, but has the advantage that it can be used for clinical trials that require frequent re-testing of subjects to see whether a new treatment is working.”

Questions or comments? Please contact Dan Peterson