Neuropsychological Test Performance of Cognitively Healthy Centenarians: Normative data from the Dutch 100-plus Study

ABSTRACT Background The population who reaches the extreme age of 100 years is growing. At this age, dementia incidence is high and cognitive functioning is variable and influenced by sensory impairments. Appropriate cognitive testing requires normative data generated specifically for this group. Currently, these are lacking. We set out to generate norms for neuropsychological tests in cognitively healthy centenarians while taking sensory impairments into account. Methods We included 235 centenarians (71.5% female) from the 100-plus Study, who self-reported to be cognitively healthy, which was confirmed by an informant and a trained researcher. Normative data were generated for 15 tests that evaluate global cognition, pre-morbid intelligence, attention, language, memory, executive and visuo-spatial functions by multiple linear regressions and/or percentiles. Centenarians with vision and/or hearing impairments were excluded for tests that required these faculties. Results Subjects scored on average 25.6±3.1 (range 17-30, interquartile-range 24-28) points on the MMSE. Vision problems and fatigue often complicated the ability to complete tests, and these problems explained 41% and 22% of the missing test scores respectively, whereas hearing problems (4%) and task incomprehension (6%) only rarely did. Sex and age showed a limited association with test performance, whereas educational level was associated with performance on the majority of the tests. Conclusions Normative data for the centenarian population is provided, while taking age-related sensory impairments into consideration. Results indicate that, next to vision impairments, fatigue and education level should be taken into account when assessing cognitive functioning in centenarians.