Functional Deficits Among Patients with Mild Cognitive Impairment

Background: Diagnostic criteria for mild cognitive impairment (MCI) include no significant functional decline, but recent studies have suggested that subtle deficits often exist. It is not known whether these differ by MCI type. We investigated the level and type of functional impairment among patients with MCI.

Methods: We studied 498 patients, evaluated at the Alzheimer's Disease Research Centers of California between 2006 and 2009, who had multidisciplinary evaluations by experts, including neurologic examination and neuropsychological testing. Patients were diagnosed with MCI and subtype was determined using cognitive domain scores. In a cross-sectional descriptive study, we examined whether functional impairment differed by MCI subtype, using the Blessed Roth Dementia Rating Scale (range: 0-17, higher scores indicating more impairment).

Results: Among the participants, the mean age was 75.4 years, 50.7% were women, and 81.7% were white. Patients with amnestic- (n = 392, 78.7%) and nonamnestic-type (n = 106, 21.3%) MCI had similar total Blessed Roth Dementia Rating Scale (1.6 and 1.5, respectively; P = .84) and Mini-Mental State Examination (26.5 and 26.7, respectively; P = .60) scores. Patients with amnestic MCI were more likely to have difficulty in remembering lists and recalling recent events (P < .05 for both) and less likely to have difficulty in eating and with continence (P = .01 for both), as compared with those with nonamnestic MCI.

Conclusions: Despite the MCI diagnostic criteria suggesting no functional impairment, our results indicate that patients with MCI experience mild functional deficits that vary according to the type of MCI.