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South Med J. Author manuscript; available in PMC 2017 September 01. Published in final edited form as: South Med J. 2016 September ; 109(9): 560–565. doi:10.14423/SMJ.0000000000000511.
Utility of the Montreal Cognitive Assessment as a Screening Test for Neurocognitive Dysfunction in Adults with Sickle Cell Disease
Cody Cichowitz, BS, Patrick C. Carroll, MD, John J. Strouse, MD, PhD, Carlton Haywood Jr, PhD, MA, and Sophie Lanzkron, MD, MHS Departments of Psychiatry and Behavioral Medicine, Pediatrics, and Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
Abstract Objectives—Neurocognitive dysfunction is an important complication of sickle cell disease(SCD), but little is published on the utility of screening tests for cognitive impairment in people with the disease. The purpose of this study was to evaluate the Montreal Cognitive Assessment (MoCA) as a screening tool and identify predictors of MoCA performance in adults with sickle cell disease.
Methods—We conducted a retrospective, cross-sectional study of the first 100 adult patients with SCD who completed the MoCA as part of routine clinical care at the Johns Hopkins Sickle Cell Center for Adults. We abstracted demographic, laboratory, and clinical data from each participant’s electronic medical record up to the date that the MoCA was administered. The factorial validity of each MoCA domain was analyzed using standard psychometric statistics. We evaluated the abstracted data for associations with the composite MoCA score and looked for independent predictors of performance using multivariable regressions.
Results—Components of the MoCA performed well in psychometric analyses and identified deficits in executive function that were described in other studies. Forty-six percent of participants fell below the cutoff for mild cognitive impairment. Increased education was an independent predictor of increased MoCA score (3.1, 95% confidence interval [CI] 1.5–4.7), whereas cerebrovascular accidents and chronic kidney disease were independent predictors of decreased score (−3.3, 95% CI −5.7 to −0.97 and −3.2, 95% CI −6.2 to −0.11, respectively). When analysis was restricted to patients with SCD, increased education (3.7, 95% CI −2.2–5.2) and a history of hydroxyurea therapy (2.0, 95% CI 0.022 to 4.0) were independent predictors of a higher score, whereas chronic kidney disease ( −3.3, 95% CI −6.4 to −0.24) and increased aspartate transaminase ( −0.045, 95% CI −0.089 to −0.0010) were independent predictors of a decreased score.
Correspondence to Mr Cody Cichowitz, A NEED ADDRESS. [email protected]
APls provide departmental address at Hopkins to which correspondence should be sent. To purchase a single copy of this article, visit sma.org/smj-home. To purchase larger reprint quantities, please contact [email protected]
The remaining authors have no financial relationships to disclose and no conflicts of interest to report.
Cichowitz et al.
Conclusions—The MoCA showed promise by identifying important cognitive deficits and associations with chronic complications and therapy. Keywords sickle cell disease; cognitive impairment; Montreal Cognitive Assessment; screening The Cooperative Study of Sickle Cell Disease was a longitudinal, observational study that identified stroke, silent cerebral infarct, and neurological deficits as important complications of sickle cell disease (SCD) in children.1–3 Several studies have estimated that approximately one-third of children with sickle cell anemia (SCA) experience silent cerebral infarcts and associated cognitive impairment.1,4–8 Research also has identified neuropsychological dysfunction in adults as an important, understudied complication associated with SCD.9–14
In the past few years, investigators have compared neurologically asymptomatic adults with SCA to African American controls and found that those with SCA had lower mean performance IQ scores as measured by the Wechsler Adult Intelligence Scale.9,14 Moreover, those with SCA were more likely than those without SCA to have decreased measures of processing speed, working memory, global cognitive function (full-scale IQ), executive function, and selective attention.9 As a part of those research studies, magnetic resonance imaging was performed on adults with SCA and revealed an increased risk for neuroanatomical abnormalities when compared with controls. These abnormalities included a thinner frontal lobe cortex and reduced volume in the thalamus and basal ganglia.14
Despite the significant amount of research describing neurocognitive impairment in children with SCD, there have been no studies highlighting the utility or results of commonly used screening tests for cognitive impairment such as the Mini-Mental State Examination in adults with SCD. A reliable and easy-to-administer screening test for cognitive impairment in SCD would allow clinicians to quickly and accurately identify those patients who need more definitive neurocognitive evaluation. The need for a screening test is accentuated further by the prevalence, the implicit chronicity, and the devastating impact of cognitive dysfunction.
At the Johns Hopkins Sickle Cell Center for Adults, we administer the Montreal Cognitive Assessment (MoCA) at regularly scheduled outpatient appointments as part of routine clinical care. The MoCA was designed to screen for mild cognitive impairment and has greater sensitivity and specificity than the Mini-Mental State Examination to identify mild cognitive impairment and mild Alzheimer disease.15 In addition, the MoCA contains timed elements and executive tasks that probe for specific cognitive deficits identified in previous studies.9,14 The MoCA consists of 22 questions that assess cognitive function across 7 domains: visuospatial and executive function, naming, attention, language, abstraction, delayed recall, and orientation. It takes approximately 10 minutes to complete the assessment, making the MoCA relatively easy to implement in daily clinical care.16 The MoCA was published in 2005 and has been incorporated in more than 200 studies involving more than 20 different specific clinical diseases.16 It is scored out of 30 points,
South Med J. Author manuscript; available in PMC 2017 September 01.
Cichowitz et al.
and a score of 12th grade Sex, male Age, decades
Aspartate aminotransferase, U/L
thalassemia (n = 64)
CI, confidence interval; CKD, chronic kidney disease; CVA, cerebrovascular accident; MoCA, Montreal Cognitive Assessment.
Author Manuscript South Med J. Author manuscript; available in PMC 2017 September 01.