Cognitive failures in healthy middle-aged Spanish adults: A cross-sectional study describing magnitude categories of subjective cognitive deficits

© 2019 Background and objectives: Healthy people with intact cognitive functioning may also experience subjective cognitive deficits (SCD). However, no study has thoroughly explored these symptoms in healthy Spaniards. Therefore, we aimed to: (i) describe the pattern of SCD in this population, (ii) report magnitude categories of SCD, and (iii) correlate SCD with age, gender and years of education. Methods: 102 healthy Spaniards (51 men) were recruited. Men and women subgroups were matched by age and years of education. SCD were evaluated using the 20-item Perceived Deficits Questionnaire (PDQ-20). Magnitude categories of SCD were described as distribution-based quartiles of the total PDQ-20 score, with higher scores/quartiles indicating greater SCD. Participants with a total PDQ-20 score greater than 2 standard deviations (SD) above normal variation were considered at risk of clinically significant SCD. Results: Mean total PDQ-20 score was 17.98 (SD = 8.29), with higher scores on “Attention/Concentration” and “Retrospective Memory” subscales than on “Planning/Organization” and “Prospective Memory” subscales. Total PDQ-20 score distribution by quartile was: 0–11 (1st quartile), 12–17 (2nd quartile), 18–23 (3rd quartile) and 24–80 (4th quartile). Only 1.96% of participants were at risk of clinically significant SCD. There was a marginal trend in the association between age and “Retrospective Memory” subscale (rs = 0.256; p = 0.009). Conclusions: Our findings may help health professionals interpret PDQ-20 scores more accurately in clinical settings. A total PDQ-20 score equal or greater to 35 may be a valid threshold for identifying people at risk of clinically significant SCD. Assessment of SCD may improve the ecological validity of research on human cognition.