VA researchers are developing a new tool to assess symptoms of posttraumatic stress disorder. Known as a computerized-adaptive test (CAT), the new system uses a computer algorithm to adapt questions in real time based on the patient's answers to the previous items. This allows the test to determine symptom levels faster and more accurately than many pen-and-paper assessments. The tool needs further validation, but the researchers hope it will become a new option for clinicians.
The researchers reported on the test in the journal Psychiatric Services.
An estimated 14 percent of Iraq and Afghanistan Veterans have PTSD, while about 10 to 12 percent of Gulf War Veterans and 30 percent of Vietnam Veterans are affected. Accurate assessment is crucial for prescribing treatment, and monitoring progress. Yet the Institute of Medicine recently reported that a lack of routine outcome measures for PTSD makes it challenging to tell if treatments are effective.
Adaptive computer tests offer more individualized assessment
Test-takers get a more individualized assessment because they are not answering questions that may not apply to them.
The researchers explain that the new testing approach offers increased precision. Test-takers get a more individualized assessment because they are not answering questions that may not apply to them. By asking patients questions based on their actual symptoms, the CAT can more accurately assess each individual.
A quick, computer-based PTSD assessment would be valuable in fast-paced clinical settings, according to the study authors. Pen-and-paper tests such as the PTSD Checklist can take as long as 10 minutes to complete. Clinicians must also take time to score and process the tests. In contrast, 89 percent of participants in the study completed the PTSD CAT in less than three minutes.
According to VA's National Center for PTSD, clinicians should consider many factors when choosing a PTSD assessment tool, such as how long it takes to administer and whether it assesses the areas the clinician wants to examine. The CAT could be a valuable addition to the PTSD screens already available, say the researchers.
The new test showed strong validity and required only eight items to accurately and reliably identify low PTSD symptom severity. To identify high symptom severity, it needed only six items. Pen-and-paper PTSD screens often require as many as 35 items.
Clinicians already use CATs for conditions such as anxiety, depression, and community integration. The authors hope the new CAT can lead to accurate and fast clinical screening for PTSD as well.
Software adjusts to the patient
The adaptive algorithms at the root of CATs allow them to accurately assess health status with high sensitivity and accuracy, according to the study authors. CATs work by first asking a base question selected for its high information value. The PTSD CAT begins by asking patients how strongly they agree with the statement "I felt upset when I was reminded of the trauma." The software then uses the patient's response to choose the next question so as to elicit the most discriminating information. The progression of questions is different for each patient. They are designed to assess the four key domains of PTSD symptoms as defined in the Diagnostic and Statistical Manual for Mental Health (DSM), 5th Edition: reliving the traumatic event; avoiding situations that trigger memories of the event; negative changes in beliefs and feelings; and hyperarousal.
The researchers developed the new CAT by first asking 1,085 Veterans to respond to 89 questions extracted or adapted from other PTSD tests. They then used this item bank to build a computer test that would cover the diagnostic criteria of PTSD as defined by the DSM.
Once the CAT prototype was ready, the researchers administered it to 203 other Veterans. By comparing these results to those from other PTSD screening tools, the researchers verified that the CAT was accurate and reliable, although they emphasize that it still requires further testing.
The researchers believe that, in addition to being used to evaluate PTSD symptom severity, the CAT could potentially be used to evaluate the outcomes of PTSD treatment and to screen for possible PTSD.
Patients in the study took the PTSD CAT on a tablet computer. The researchers say it can also be installed on smartphones and other devices. They add that the CAT could even be administered over a secure Internet portal such as VA's MyhealtheVet.
The VA-funded study included researchers with the Center for Healthcare Organization and Implementation Research at the Edith Nourse Rogers Memorial Veterans Hospital, in Bedford, Mass; the Massachusetts Veterans Epidemiology Research and Information Center, based at the VA Boston Health Care System; and the Center for Chronic Disease Outcomes Research, at the Minneapolis VA Health Care System. The team also included authors with Boston University and the University of Massachusetts.