Validating a Pragmatic Approach to Cognitive Screening in Stroke Prevention Clinics Using the Montreal Cognitive Assessment

Abstract

Cognitive screening in patients with stroke is endorsed by Best Practice Recommendations, 7 and rapid cognitive assessments are widely used in clinic settings to understand patient function and tailor appropriate therapy. The Montreal CognitiveBackground and Purpose-The Montreal Cognitive Assessment (MoCA) is used commonly to identify cognitive impairment (CI), but there are multiple published cut points for normal and abnormal. We seek to validate a pragmatic approach to screening for moderate-severe CI, by classifying patients into high-, intermediate-, and low-risk categories. Methods-A total of 390 participants attending an academic Stroke Prevention Clinic completed the MoCA and more detailed neuropsychological testing. Between April 23, 2012 and April 30, 2014, all consecutive new referrals to the regional Stroke Prevention Clinic who were English-speaking, not severely aphasic, and could see and write well enough to complete neuropsychological testing were assessed for inclusion, and consenting patients were enrolled. CI was defined as ≥2 SDs below normal for age and education on at least 2 cognitive subtests. A single cut point for CI was compared with 2 cut points (high sensitivity and high specificity) generated using receiver operator characteristic and area under the curve analyses. The intermediate-risk group contained those scoring between the 2 cut points. Results-Thirty-four percent of participants had a symptomatic or silent stroke, 34% were seen for possible or probable transient ischemic attack, and 32% were diagnosed with other vascular or nonvascular conditions. Using a single cut point, sensitivity and specificity were optimal with MoCA ≤22, (sensitivity=60.4%, specificity=89.9%, area under the curve=0.801, positive predictive value=48.5%, negative predictive value=93.5%, positive likelihood ratio=6, and negative likelihood ratio=0.4). Using 2 cut points, sensitivity was optimal with MoCA ≥28 (sensitivity=96.2%, negative predictive value =97.6%, and negative likelihood ratio=1.27), and specificity was optimal with MoCA ≤22 (specificity=89.9%, positive predictive value=48.5%, and positive likelihood ratio=6). 9 There is considerable variability in the diagnostic characteristics of the MoCA within the population with stroke (Table I in the online-only Data Supplement); most commonly, a cut point of ≥26 is considered normal, whereas ≤25 is considered impaired. Conclusions-Stratifying8 This dichotomization stems from the statistical approach to receiver-operating curves, but contradicts clinical thought processes in which screening questions are used throughout a clinical encounter to decide serious concern, no concern, or possible concern and guide further questioning or appropriate actions. The MoCA has been shown to be more sensitive to vascular CI than other quick screens (eg, the Folstein Mini-Mental State Examination), but less specific. [10][11][12] However, this reflects the use of a single cut point. In both clinical practice and research, the MoCA is often used as a surrogate for CI...

The “DOC” screen: Feasible and valid screening for depression, Obstructive Sleep Apnea (OSA) and cognitive impairment in stroke prevention clinics

“…[33] Our results display excellent diagnostic characteristics for the PHQ-2, STOP and MoCA components (Tables 7–9). DOC-Mood displayed excellent sensitivity and specificity for detecting depression using the two cut-point approach (92%, 99%).…”

“…Using the two-cut point approach,[33] AUC for the DOC-Mood is 0.898, sensitivity is optimal with DOC-Mood = 0 (sensitivity = 92%, NPV = 97%, -LR = 3.3), and specificity is optimal with DOC-Mood≥4 (specificity = 99%, PPV = 90%, +LR = 37) (Fig 3A). 10% of participants scored ≥4, and were classified as high-risk for depression.…”

“…This relationship was also observed using the full MoCA. [33] DOC-Cog logistic regression modeling controlling for age, sex and education reduced the number of participants who score intermediate-risk from 66% to 46%, while maintaining excellent sensitivity and specificity. The DOC-Cog is an accurate alternative tool compared to the MoCA for detecting cognitive impairment in busy clinic settings.…”

“…Diagnostic cut-points were determined using a previously validated method. [33] Two diagnostic cut-points were determined using the ROC curve, and a cut-point with high sensitivity and a second cut-point with high specificity were determined. This analysis was run for each sub-score of the DOC screen.…”

Neuromodulation Using Transcranial Magnetic Stimulation (TMS)

“…The MoCA test has shown to be more sensitive in verifying vascular-induced cognitive loss, relative to quick screening tests, such as the Mini-Mental State Exam, but it is less specific; the MMSE is more specific for detecting dementia, but, on the other hand, it is more restricted and does not encompass an assessment of executive functions, as the MoCA does. This aspect is taken into consideration by the latter test, which is currently preferred for detecting cognitive loss after a stroke 6 . The role of the assessment is not restricted to verifying deficits, but also to monitor and provide elements for rehabilitation programs, such as treatment with TMS, which is being considered an efficient tool in neurorehabilitation.…”