Validity of Montreal Cognitive Assessment to Detect Cognitive Impairment in Individuals with Type 2 Diabetes

Type 2 diabetes (T2D) is a risk factor for cognitive dysfunction which potentially impacts diabetes self-management skills. Guidelines recommend screening older adults with diabetes for early detection of cognitive impairment. For screening cognitive impairment in busy endocrine clinics, we need a test that is easy and rapid to administer, sensitive enough to pick the cognitive deficits of T2D and at the same time gives less false-positive outcomes. The Montreal Cognitive Assessment (MoCA) scale is a widely available cognitive screening tool, but there are no studies evaluating its discriminant properties in people with diabetes. We evaluated the performance metrics of MoCA in this population. We found mild cognitive impairment in four out of ten participants with T2D at or above 60 years of age. At the recommended cut-off on MoCA (< 26), the sensitivity was high, but the specificity quite low. We found better diagnostic accuracy at lower cut-offs (20/21), with high specificity but a lower sensitivity. At this cut-off, approximately one out of five people screened using MoCA would require detailed neuropsychological testing, and four out of five who undergo detailed evaluation would have true cognitive impairment.