Researchers Suggest Which Test is Best to Screen for Cognitive Impairment in SLE Patients
The Montreal Cognitive Assessment (MoCA) may be a useful clinical tool for screening cognitive impairment in patients with systemic lupus erythematosus (SLE), a new study shows.
The study titled, “Performance of Screening Tests for Cognitive Impairment in Systemic Lupus Erythematosus,” was published in the Journal of Rheumatology.
Cognitive impairment is when a person ” has trouble remembering, learning new things, concentrating, or making decisions that affect their everyday life,” according to the Centers for Disease Control and Prevention (CDC). It is a common characteristic of lupus and has been reported as being prevalent in 20-80 percent of the lupus population, according to multiple studies.
Because cognitive impairment has the ability to decrease patients’ quality of life, early diagnosis is essential so patients can take the necessary steps to prevent or decrease cognitive decline.
Currently, a lack of screening tools for cognitive impairment in lupus patients is leading to a delay in diagnosing the condition in patients with the chronic autoimmune disease. Researchers at the University of Toronto set out to explore the best tool to measure cognitive impairment specifically among patients with lupus.
Researchers administered three different cognitive tests to patients diagnosed with lupus: the MoCA, Mini Mental State Examination (MMSE), and Hopkins Verbal Learning Test–Revised (HVLT- R). The sensitivity, specificity, positive predictive value, negative predictive value, and positive likelihood ratio was determined for the MoCA/MMSE and compared to the HVLT-R.
Sensitivity refers to the ability of a test to correctly identify patients with the disease while the specificity is the ability to correctly identify people who do not have the disease. The positive predictive value refers to the probability that patients who test positive for a disease actually have the disease and negative predictive value refers to the probability that people who test negative for a disease actually do not have it. The likelihood ratio is the probability that an individual with the disease tested positive for the disease divided by the probability that a person without the disease tested positive for the disease.
The researchers showed that out of 98 patients, 48 percent had cognitive impairment using the MoCA screening tool, while 31 percent had it using the HVLT-R. The sensitivity of the MoCA was fairly high, at 73 percent, compared to only 27 percent of the MMSE. However, the specificity of MMSE was higher, at 90 percent, than the MoCA, which was only 63 percent.
Furthermore, the positive predictive value was similar between the MoCA and the MMSE, at 47 percent and 53 percent, respectively. The likelihood ratio was also similar between the MoCA and the MMSE at 2 and 2.6, respectively. However, the negative predictive value was higher in patients who took the MoCA, at 84 percent, than the MMSE, at 74 percent.
Researchers also looked at variables that may affect the prevalence of cognitive impairment in lupus patients in an effort to identify risk factors for the condition. They discovered that patients with higher education were less likely to develop cognitive decline. The authors believe that educational exposure may increase cognitive reserve, allowing more educated patients to cope better with the factors that could contribute to cognitive decline.
Researchers also discovered that patients who have had lupus longer were less likely to develop cognitive impairment. However, the limitation to this finding is that patients with more severe cognitive impairment were not able to participate in the study.