Cognitive performance of community-dwelling oldest-old individuals with major depression: the Pietà study

Individuals with late-life depression (LLD) may present cognitive symptoms. We sought to determine whether a brief cognitive battery (BCB) could identify cognitive and functional deficits in oldest-old individuals with LLD and a low level of education.

We evaluated 639 community-dwelling individuals aged 75+ years in Caeté (MG), Brazil. We used the MINI and GDS-15 to diagnose major depression and evaluate its severity, respectively. The cognitive evaluation comprised the Mini-Mental State Examination (MMSE), BCB, clock-drawing test, category fluency test (animals) and Pfeffer's Functional Activities Questionnaire (FAQ).

Fifty-four (11.6%) of the included individuals were diagnosed with LLD; on average, these participants were aged 81.0 ± 4.8 years and had 3.9 ± 3.4 years of schooling, and 77.8% of the subjects with LLD were female. Depressed individuals scored lower than subjects without dementia/depression on the MMSE overall (p < 0.001) and on several of the MMSE subscales, namely, time (p < 0.001) and spatial orientation (p = 0.021), attention/calculation (p = 0.019), and language (p = 0.004). Individuals with LLD performed worse on the incidental and (p = 0.011) immediate memory (p = 0.046) and learning tasks (p = 0.039) of the BCB. Individuals with LLD also performed worse on the category fluency test (p = 0.006), clock-drawing test (p = 0.011) and FAQ (p < 0.001). Depression severity was negatively correlated with incidental memory (ρ = -0.412; p = 0.003) and positively correlated with FAQ score (ρ = 0.308; p = 0.035). In the multiple regression analysis, only temporal orientation and FAQ score remained independently associated with LLD.

Individuals with depression and a low level of education presented several cognitive and functional deficits. Depression severity was negatively correlated with incidental memory and functionality. Our findings serve as a description of the presence of cognitive dysfunction in individuals with LLD and suggest that these deficits may be identified based on the results of a BCB.